xref: /openbsd-src/gnu/usr.bin/perl/regexec.c (revision 42c0683c5609fe346691c97e80c553467d6eec66)
1 /*    regexec.c
2  */
3 
4 /*
5  *	One Ring to rule them all, One Ring to find them
6  *
7  *     [p.v of _The Lord of the Rings_, opening poem]
8  *     [p.50 of _The Lord of the Rings_, I/iii: "The Shadow of the Past"]
9  *     [p.254 of _The Lord of the Rings_, II/ii: "The Council of Elrond"]
10  */
11 
12 /* This file contains functions for executing a regular expression.  See
13  * also regcomp.c which funnily enough, contains functions for compiling
14  * a regular expression.
15  *
16  * This file is also copied at build time to ext/re/re_exec.c, where
17  * it's built with -DPERL_EXT_RE_BUILD -DPERL_EXT_RE_DEBUG -DPERL_EXT.
18  * This causes the main functions to be compiled under new names and with
19  * debugging support added, which makes "use re 'debug'" work.
20  */
21 
22 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
23  * confused with the original package (see point 3 below).  Thanks, Henry!
24  */
25 
26 /* Additional note: this code is very heavily munged from Henry's version
27  * in places.  In some spots I've traded clarity for efficiency, so don't
28  * blame Henry for some of the lack of readability.
29  */
30 
31 /* The names of the functions have been changed from regcomp and
32  * regexec to  pregcomp and pregexec in order to avoid conflicts
33  * with the POSIX routines of the same names.
34 */
35 
36 #ifdef PERL_EXT_RE_BUILD
37 #include "re_top.h"
38 #endif
39 
40 /*
41  * pregcomp and pregexec -- regsub and regerror are not used in perl
42  *
43  *	Copyright (c) 1986 by University of Toronto.
44  *	Written by Henry Spencer.  Not derived from licensed software.
45  *
46  *	Permission is granted to anyone to use this software for any
47  *	purpose on any computer system, and to redistribute it freely,
48  *	subject to the following restrictions:
49  *
50  *	1. The author is not responsible for the consequences of use of
51  *		this software, no matter how awful, even if they arise
52  *		from defects in it.
53  *
54  *	2. The origin of this software must not be misrepresented, either
55  *		by explicit claim or by omission.
56  *
57  *	3. Altered versions must be plainly marked as such, and must not
58  *		be misrepresented as being the original software.
59  *
60  ****    Alterations to Henry's code are...
61  ****
62  ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
63  ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
64  ****    by Larry Wall and others
65  ****
66  ****    You may distribute under the terms of either the GNU General Public
67  ****    License or the Artistic License, as specified in the README file.
68  *
69  * Beware that some of this code is subtly aware of the way operator
70  * precedence is structured in regular expressions.  Serious changes in
71  * regular-expression syntax might require a total rethink.
72  */
73 #include "EXTERN.h"
74 #define PERL_IN_REGEXEC_C
75 #include "perl.h"
76 
77 #ifdef PERL_IN_XSUB_RE
78 #  include "re_comp.h"
79 #else
80 #  include "regcomp.h"
81 #endif
82 
83 #include "invlist_inline.h"
84 #include "unicode_constants.h"
85 
86 #define B_ON_NON_UTF8_LOCALE_IS_WRONG            \
87  "Use of \\b{} or \\B{} for non-UTF-8 locale is wrong.  Assuming a UTF-8 locale"
88 
89 static const char utf8_locale_required[] =
90       "Use of (?[ ]) for non-UTF-8 locale is wrong.  Assuming a UTF-8 locale";
91 
92 #ifdef DEBUGGING
93 /* At least one required character in the target string is expressible only in
94  * UTF-8. */
95 static const char* const non_utf8_target_but_utf8_required
96                 = "Can't match, because target string needs to be in UTF-8\n";
97 #endif
98 
99 #define NON_UTF8_TARGET_BUT_UTF8_REQUIRED(target) STMT_START {           \
100     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "%s", non_utf8_target_but_utf8_required));\
101     goto target;                                                         \
102 } STMT_END
103 
104 #define HAS_NONLATIN1_FOLD_CLOSURE(i) _HAS_NONLATIN1_FOLD_CLOSURE_ONLY_FOR_USE_BY_REGCOMP_DOT_C_AND_REGEXEC_DOT_C(i)
105 
106 #ifndef STATIC
107 #define	STATIC	static
108 #endif
109 
110 /* Valid only if 'c', the character being looke-up, is an invariant under
111  * UTF-8: it avoids the reginclass call if there are no complications: i.e., if
112  * everything matchable is straight forward in the bitmap */
113 #define REGINCLASS(prog,p,c,u)  (ANYOF_FLAGS(p)                             \
114                                 ? reginclass(prog,p,c,c+1,u)                \
115                                 : ANYOF_BITMAP_TEST(p,*(c)))
116 
117 /*
118  * Forwards.
119  */
120 
121 #define CHR_SVLEN(sv) (utf8_target ? sv_len_utf8(sv) : SvCUR(sv))
122 #define CHR_DIST(a,b) (reginfo->is_utf8_target ? utf8_distance(a,b) : a - b)
123 
124 #define HOPc(pos,off) \
125 	(char *)(reginfo->is_utf8_target \
126 	    ? reghop3((U8*)pos, off, \
127                     (U8*)(off >= 0 ? reginfo->strend : reginfo->strbeg)) \
128 	    : (U8*)(pos + off))
129 
130 #define HOPBACKc(pos, off) \
131 	(char*)(reginfo->is_utf8_target \
132 	    ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(reginfo->strbeg)) \
133 	    : (pos - off >= reginfo->strbeg)	\
134 		? (U8*)pos - off		\
135 		: NULL)
136 
137 #define HOP3(pos,off,lim) (reginfo->is_utf8_target  ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
138 #define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
139 
140 /* lim must be +ve. Returns NULL on overshoot */
141 #define HOPMAYBE3(pos,off,lim) \
142 	(reginfo->is_utf8_target                        \
143 	    ? reghopmaybe3((U8*)pos, off, (U8*)(lim))   \
144 	    : ((U8*)pos + off <= lim)                   \
145 		? (U8*)pos + off                        \
146 		: NULL)
147 
148 /* like HOP3, but limits the result to <= lim even for the non-utf8 case.
149  * off must be >=0; args should be vars rather than expressions */
150 #define HOP3lim(pos,off,lim) (reginfo->is_utf8_target \
151     ? reghop3((U8*)(pos), off, (U8*)(lim)) \
152     : (U8*)((pos + off) > lim ? lim : (pos + off)))
153 
154 #define HOP4(pos,off,llim, rlim) (reginfo->is_utf8_target \
155     ? reghop4((U8*)(pos), off, (U8*)(llim), (U8*)(rlim)) \
156     : (U8*)(pos + off))
157 #define HOP4c(pos,off,llim, rlim) ((char*)HOP4(pos,off,llim, rlim))
158 
159 #define NEXTCHR_EOS -10 /* nextchr has fallen off the end */
160 #define NEXTCHR_IS_EOS (nextchr < 0)
161 
162 #define SET_nextchr \
163     nextchr = ((locinput < reginfo->strend) ? UCHARAT(locinput) : NEXTCHR_EOS)
164 
165 #define SET_locinput(p) \
166     locinput = (p);  \
167     SET_nextchr
168 
169 
170 #define LOAD_UTF8_CHARCLASS(swash_ptr, property_name, invlist) STMT_START {   \
171         if (!swash_ptr) {                                                     \
172             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;                       \
173             swash_ptr = _core_swash_init("utf8", property_name, &PL_sv_undef, \
174                                          1, 0, invlist, &flags);              \
175             assert(swash_ptr);                                                \
176         }                                                                     \
177     } STMT_END
178 
179 /* If in debug mode, we test that a known character properly matches */
180 #ifdef DEBUGGING
181 #   define LOAD_UTF8_CHARCLASS_DEBUG_TEST(swash_ptr,                          \
182                                           property_name,                      \
183                                           invlist,                            \
184                                           utf8_char_in_property)              \
185         LOAD_UTF8_CHARCLASS(swash_ptr, property_name, invlist);               \
186         assert(swash_fetch(swash_ptr, (U8 *) utf8_char_in_property, TRUE));
187 #else
188 #   define LOAD_UTF8_CHARCLASS_DEBUG_TEST(swash_ptr,                          \
189                                           property_name,                      \
190                                           invlist,                            \
191                                           utf8_char_in_property)              \
192         LOAD_UTF8_CHARCLASS(swash_ptr, property_name, invlist)
193 #endif
194 
195 #define LOAD_UTF8_CHARCLASS_ALNUM() LOAD_UTF8_CHARCLASS_DEBUG_TEST(           \
196                                         PL_utf8_swash_ptrs[_CC_WORDCHAR],     \
197                                         "",                                   \
198                                         PL_XPosix_ptrs[_CC_WORDCHAR],         \
199                                         LATIN_SMALL_LIGATURE_LONG_S_T_UTF8);
200 
201 #define PLACEHOLDER	/* Something for the preprocessor to grab onto */
202 /* TODO: Combine JUMPABLE and HAS_TEXT to cache OP(rn) */
203 
204 /* for use after a quantifier and before an EXACT-like node -- japhy */
205 /* it would be nice to rework regcomp.sym to generate this stuff. sigh
206  *
207  * NOTE that *nothing* that affects backtracking should be in here, specifically
208  * VERBS must NOT be included. JUMPABLE is used to determine  if we can ignore a
209  * node that is in between two EXACT like nodes when ascertaining what the required
210  * "follow" character is. This should probably be moved to regex compile time
211  * although it may be done at run time beause of the REF possibility - more
212  * investigation required. -- demerphq
213 */
214 #define JUMPABLE(rn) (                                                             \
215     OP(rn) == OPEN ||                                                              \
216     (OP(rn) == CLOSE &&                                                            \
217      !EVAL_CLOSE_PAREN_IS(cur_eval,ARG(rn)) ) ||                                   \
218     OP(rn) == EVAL ||                                                              \
219     OP(rn) == SUSPEND || OP(rn) == IFMATCH ||                                      \
220     OP(rn) == PLUS || OP(rn) == MINMOD ||                                          \
221     OP(rn) == KEEPS ||                                                             \
222     (PL_regkind[OP(rn)] == CURLY && ARG1(rn) > 0)                                  \
223 )
224 #define IS_EXACT(rn) (PL_regkind[OP(rn)] == EXACT)
225 
226 #define HAS_TEXT(rn) ( IS_EXACT(rn) || PL_regkind[OP(rn)] == REF )
227 
228 #if 0
229 /* Currently these are only used when PL_regkind[OP(rn)] == EXACT so
230    we don't need this definition.  XXX These are now out-of-sync*/
231 #define IS_TEXT(rn)   ( OP(rn)==EXACT   || OP(rn)==REF   || OP(rn)==NREF   )
232 #define IS_TEXTF(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFU_SS || OP(rn)==EXACTFA || OP(rn)==EXACTFA_NO_TRIE || OP(rn)==EXACTF || OP(rn)==REFF  || OP(rn)==NREFF )
233 #define IS_TEXTFL(rn) ( OP(rn)==EXACTFL || OP(rn)==REFFL || OP(rn)==NREFFL )
234 
235 #else
236 /* ... so we use this as its faster. */
237 #define IS_TEXT(rn)   ( OP(rn)==EXACT || OP(rn)==EXACTL )
238 #define IS_TEXTFU(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFLU8 || OP(rn)==EXACTFU_SS || OP(rn) == EXACTFA || OP(rn) == EXACTFA_NO_TRIE)
239 #define IS_TEXTF(rn)  ( OP(rn)==EXACTF  )
240 #define IS_TEXTFL(rn) ( OP(rn)==EXACTFL )
241 
242 #endif
243 
244 /*
245   Search for mandatory following text node; for lookahead, the text must
246   follow but for lookbehind (rn->flags != 0) we skip to the next step.
247 */
248 #define FIND_NEXT_IMPT(rn) STMT_START {                                   \
249     while (JUMPABLE(rn)) { \
250 	const OPCODE type = OP(rn); \
251 	if (type == SUSPEND || PL_regkind[type] == CURLY) \
252 	    rn = NEXTOPER(NEXTOPER(rn)); \
253 	else if (type == PLUS) \
254 	    rn = NEXTOPER(rn); \
255 	else if (type == IFMATCH) \
256 	    rn = (rn->flags == 0) ? NEXTOPER(NEXTOPER(rn)) : rn + ARG(rn); \
257 	else rn += NEXT_OFF(rn); \
258     } \
259 } STMT_END
260 
261 #define SLAB_FIRST(s) (&(s)->states[0])
262 #define SLAB_LAST(s)  (&(s)->states[PERL_REGMATCH_SLAB_SLOTS-1])
263 
264 static void S_setup_eval_state(pTHX_ regmatch_info *const reginfo);
265 static void S_cleanup_regmatch_info_aux(pTHX_ void *arg);
266 static regmatch_state * S_push_slab(pTHX);
267 
268 #define REGCP_PAREN_ELEMS 3
269 #define REGCP_OTHER_ELEMS 3
270 #define REGCP_FRAME_ELEMS 1
271 /* REGCP_FRAME_ELEMS are not part of the REGCP_OTHER_ELEMS and
272  * are needed for the regexp context stack bookkeeping. */
273 
274 STATIC CHECKPOINT
275 S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
276 {
277     const int retval = PL_savestack_ix;
278     const int paren_elems_to_push =
279                 (maxopenparen - parenfloor) * REGCP_PAREN_ELEMS;
280     const UV total_elems = paren_elems_to_push + REGCP_OTHER_ELEMS;
281     const UV elems_shifted = total_elems << SAVE_TIGHT_SHIFT;
282     I32 p;
283     GET_RE_DEBUG_FLAGS_DECL;
284 
285     PERL_ARGS_ASSERT_REGCPPUSH;
286 
287     if (paren_elems_to_push < 0)
288         Perl_croak(aTHX_ "panic: paren_elems_to_push, %i < 0, maxopenparen: %i parenfloor: %i REGCP_PAREN_ELEMS: %u",
289                    (int)paren_elems_to_push, (int)maxopenparen,
290                    (int)parenfloor, (unsigned)REGCP_PAREN_ELEMS);
291 
292     if ((elems_shifted >> SAVE_TIGHT_SHIFT) != total_elems)
293 	Perl_croak(aTHX_ "panic: paren_elems_to_push offset %"UVuf
294 		   " out of range (%lu-%ld)",
295 		   total_elems,
296                    (unsigned long)maxopenparen,
297                    (long)parenfloor);
298 
299     SSGROW(total_elems + REGCP_FRAME_ELEMS);
300 
301     DEBUG_BUFFERS_r(
302 	if ((int)maxopenparen > (int)parenfloor)
303             Perl_re_printf( aTHX_
304 		"rex=0x%"UVxf" offs=0x%"UVxf": saving capture indices:\n",
305 		PTR2UV(rex),
306 		PTR2UV(rex->offs)
307 	    );
308     );
309     for (p = parenfloor+1; p <= (I32)maxopenparen;  p++) {
310 /* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
311 	SSPUSHIV(rex->offs[p].end);
312 	SSPUSHIV(rex->offs[p].start);
313 	SSPUSHINT(rex->offs[p].start_tmp);
314         DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
315 	    "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"\n",
316 	    (UV)p,
317 	    (IV)rex->offs[p].start,
318 	    (IV)rex->offs[p].start_tmp,
319 	    (IV)rex->offs[p].end
320 	));
321     }
322 /* REGCP_OTHER_ELEMS are pushed in any case, parentheses or no. */
323     SSPUSHINT(maxopenparen);
324     SSPUSHINT(rex->lastparen);
325     SSPUSHINT(rex->lastcloseparen);
326     SSPUSHUV(SAVEt_REGCONTEXT | elems_shifted); /* Magic cookie. */
327 
328     return retval;
329 }
330 
331 /* These are needed since we do not localize EVAL nodes: */
332 #define REGCP_SET(cp)                                           \
333     DEBUG_STATE_r(                                              \
334         Perl_re_exec_indentf( aTHX_                                         \
335             "Setting an EVAL scope, savestack=%"IVdf",\n",      \
336             depth, (IV)PL_savestack_ix                          \
337         )                                                       \
338     );                                                          \
339     cp = PL_savestack_ix
340 
341 #define REGCP_UNWIND(cp)                                        \
342     DEBUG_STATE_r(                                              \
343         if (cp != PL_savestack_ix)                              \
344             Perl_re_exec_indentf( aTHX_                                     \
345                 "Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n",\
346                 depth, (IV)(cp), (IV)PL_savestack_ix            \
347             )                                                   \
348     );                                                          \
349     regcpblow(cp)
350 
351 #define UNWIND_PAREN(lp, lcp)               \
352     for (n = rex->lastparen; n > lp; n--)   \
353         rex->offs[n].end = -1;              \
354     rex->lastparen = n;                     \
355     rex->lastcloseparen = lcp;
356 
357 
358 STATIC void
359 S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
360 {
361     UV i;
362     U32 paren;
363     GET_RE_DEBUG_FLAGS_DECL;
364 
365     PERL_ARGS_ASSERT_REGCPPOP;
366 
367     /* Pop REGCP_OTHER_ELEMS before the parentheses loop starts. */
368     i = SSPOPUV;
369     assert((i & SAVE_MASK) == SAVEt_REGCONTEXT); /* Check that the magic cookie is there. */
370     i >>= SAVE_TIGHT_SHIFT; /* Parentheses elements to pop. */
371     rex->lastcloseparen = SSPOPINT;
372     rex->lastparen = SSPOPINT;
373     *maxopenparen_p = SSPOPINT;
374 
375     i -= REGCP_OTHER_ELEMS;
376     /* Now restore the parentheses context. */
377     DEBUG_BUFFERS_r(
378 	if (i || rex->lastparen + 1 <= rex->nparens)
379             Perl_re_printf( aTHX_
380 		"rex=0x%"UVxf" offs=0x%"UVxf": restoring capture indices to:\n",
381 		PTR2UV(rex),
382 		PTR2UV(rex->offs)
383 	    );
384     );
385     paren = *maxopenparen_p;
386     for ( ; i > 0; i -= REGCP_PAREN_ELEMS) {
387 	SSize_t tmps;
388 	rex->offs[paren].start_tmp = SSPOPINT;
389 	rex->offs[paren].start = SSPOPIV;
390 	tmps = SSPOPIV;
391 	if (paren <= rex->lastparen)
392 	    rex->offs[paren].end = tmps;
393         DEBUG_BUFFERS_r( Perl_re_printf( aTHX_
394 	    "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"%s\n",
395 	    (UV)paren,
396 	    (IV)rex->offs[paren].start,
397 	    (IV)rex->offs[paren].start_tmp,
398 	    (IV)rex->offs[paren].end,
399 	    (paren > rex->lastparen ? "(skipped)" : ""));
400 	);
401 	paren--;
402     }
403 #if 1
404     /* It would seem that the similar code in regtry()
405      * already takes care of this, and in fact it is in
406      * a better location to since this code can #if 0-ed out
407      * but the code in regtry() is needed or otherwise tests
408      * requiring null fields (pat.t#187 and split.t#{13,14}
409      * (as of patchlevel 7877)  will fail.  Then again,
410      * this code seems to be necessary or otherwise
411      * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
412      * --jhi updated by dapm */
413     for (i = rex->lastparen + 1; i <= rex->nparens; i++) {
414 	if (i > *maxopenparen_p)
415 	    rex->offs[i].start = -1;
416 	rex->offs[i].end = -1;
417         DEBUG_BUFFERS_r( Perl_re_printf( aTHX_
418 	    "    \\%"UVuf": %s   ..-1 undeffing\n",
419 	    (UV)i,
420 	    (i > *maxopenparen_p) ? "-1" : "  "
421 	));
422     }
423 #endif
424 }
425 
426 /* restore the parens and associated vars at savestack position ix,
427  * but without popping the stack */
428 
429 STATIC void
430 S_regcp_restore(pTHX_ regexp *rex, I32 ix, U32 *maxopenparen_p)
431 {
432     I32 tmpix = PL_savestack_ix;
433     PL_savestack_ix = ix;
434     regcppop(rex, maxopenparen_p);
435     PL_savestack_ix = tmpix;
436 }
437 
438 #define regcpblow(cp) LEAVE_SCOPE(cp)	/* Ignores regcppush()ed data. */
439 
440 STATIC bool
441 S_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
442 {
443     /* Returns a boolean as to whether or not 'character' is a member of the
444      * Posix character class given by 'classnum' that should be equivalent to a
445      * value in the typedef '_char_class_number'.
446      *
447      * Ideally this could be replaced by a just an array of function pointers
448      * to the C library functions that implement the macros this calls.
449      * However, to compile, the precise function signatures are required, and
450      * these may vary from platform to to platform.  To avoid having to figure
451      * out what those all are on each platform, I (khw) am using this method,
452      * which adds an extra layer of function call overhead (unless the C
453      * optimizer strips it away).  But we don't particularly care about
454      * performance with locales anyway. */
455 
456     switch ((_char_class_number) classnum) {
457         case _CC_ENUM_ALPHANUMERIC: return isALPHANUMERIC_LC(character);
458         case _CC_ENUM_ALPHA:     return isALPHA_LC(character);
459         case _CC_ENUM_ASCII:     return isASCII_LC(character);
460         case _CC_ENUM_BLANK:     return isBLANK_LC(character);
461         case _CC_ENUM_CASED:     return isLOWER_LC(character)
462                                         || isUPPER_LC(character);
463         case _CC_ENUM_CNTRL:     return isCNTRL_LC(character);
464         case _CC_ENUM_DIGIT:     return isDIGIT_LC(character);
465         case _CC_ENUM_GRAPH:     return isGRAPH_LC(character);
466         case _CC_ENUM_LOWER:     return isLOWER_LC(character);
467         case _CC_ENUM_PRINT:     return isPRINT_LC(character);
468         case _CC_ENUM_PUNCT:     return isPUNCT_LC(character);
469         case _CC_ENUM_SPACE:     return isSPACE_LC(character);
470         case _CC_ENUM_UPPER:     return isUPPER_LC(character);
471         case _CC_ENUM_WORDCHAR:  return isWORDCHAR_LC(character);
472         case _CC_ENUM_XDIGIT:    return isXDIGIT_LC(character);
473         default:    /* VERTSPACE should never occur in locales */
474             Perl_croak(aTHX_ "panic: isFOO_lc() has an unexpected character class '%d'", classnum);
475     }
476 
477     NOT_REACHED; /* NOTREACHED */
478     return FALSE;
479 }
480 
481 STATIC bool
482 S_isFOO_utf8_lc(pTHX_ const U8 classnum, const U8* character)
483 {
484     /* Returns a boolean as to whether or not the (well-formed) UTF-8-encoded
485      * 'character' is a member of the Posix character class given by 'classnum'
486      * that should be equivalent to a value in the typedef
487      * '_char_class_number'.
488      *
489      * This just calls isFOO_lc on the code point for the character if it is in
490      * the range 0-255.  Outside that range, all characters use Unicode
491      * rules, ignoring any locale.  So use the Unicode function if this class
492      * requires a swash, and use the Unicode macro otherwise. */
493 
494     PERL_ARGS_ASSERT_ISFOO_UTF8_LC;
495 
496     if (UTF8_IS_INVARIANT(*character)) {
497         return isFOO_lc(classnum, *character);
498     }
499     else if (UTF8_IS_DOWNGRADEABLE_START(*character)) {
500         return isFOO_lc(classnum,
501                         EIGHT_BIT_UTF8_TO_NATIVE(*character, *(character + 1)));
502     }
503 
504     _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(character, character + UTF8SKIP(character));
505 
506     if (classnum < _FIRST_NON_SWASH_CC) {
507 
508         /* Initialize the swash unless done already */
509         if (! PL_utf8_swash_ptrs[classnum]) {
510             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
511             PL_utf8_swash_ptrs[classnum] =
512                     _core_swash_init("utf8",
513                                      "",
514                                      &PL_sv_undef, 1, 0,
515                                      PL_XPosix_ptrs[classnum], &flags);
516         }
517 
518         return cBOOL(swash_fetch(PL_utf8_swash_ptrs[classnum], (U8 *)
519                                  character,
520                                  TRUE /* is UTF */ ));
521     }
522 
523     switch ((_char_class_number) classnum) {
524         case _CC_ENUM_SPACE:     return is_XPERLSPACE_high(character);
525         case _CC_ENUM_BLANK:     return is_HORIZWS_high(character);
526         case _CC_ENUM_XDIGIT:    return is_XDIGIT_high(character);
527         case _CC_ENUM_VERTSPACE: return is_VERTWS_high(character);
528         default:                 break;
529     }
530 
531     return FALSE; /* Things like CNTRL are always below 256 */
532 }
533 
534 /*
535  * pregexec and friends
536  */
537 
538 #ifndef PERL_IN_XSUB_RE
539 /*
540  - pregexec - match a regexp against a string
541  */
542 I32
543 Perl_pregexec(pTHX_ REGEXP * const prog, char* stringarg, char *strend,
544 	 char *strbeg, SSize_t minend, SV *screamer, U32 nosave)
545 /* stringarg: the point in the string at which to begin matching */
546 /* strend:    pointer to null at end of string */
547 /* strbeg:    real beginning of string */
548 /* minend:    end of match must be >= minend bytes after stringarg. */
549 /* screamer:  SV being matched: only used for utf8 flag, pos() etc; string
550  *            itself is accessed via the pointers above */
551 /* nosave:    For optimizations. */
552 {
553     PERL_ARGS_ASSERT_PREGEXEC;
554 
555     return
556 	regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL,
557 		      nosave ? 0 : REXEC_COPY_STR);
558 }
559 #endif
560 
561 
562 
563 /* re_intuit_start():
564  *
565  * Based on some optimiser hints, try to find the earliest position in the
566  * string where the regex could match.
567  *
568  *   rx:     the regex to match against
569  *   sv:     the SV being matched: only used for utf8 flag; the string
570  *           itself is accessed via the pointers below. Note that on
571  *           something like an overloaded SV, SvPOK(sv) may be false
572  *           and the string pointers may point to something unrelated to
573  *           the SV itself.
574  *   strbeg: real beginning of string
575  *   strpos: the point in the string at which to begin matching
576  *   strend: pointer to the byte following the last char of the string
577  *   flags   currently unused; set to 0
578  *   data:   currently unused; set to NULL
579  *
580  * The basic idea of re_intuit_start() is to use some known information
581  * about the pattern, namely:
582  *
583  *   a) the longest known anchored substring (i.e. one that's at a
584  *      constant offset from the beginning of the pattern; but not
585  *      necessarily at a fixed offset from the beginning of the
586  *      string);
587  *   b) the longest floating substring (i.e. one that's not at a constant
588  *      offset from the beginning of the pattern);
589  *   c) Whether the pattern is anchored to the string; either
590  *      an absolute anchor: /^../, or anchored to \n: /^.../m,
591  *      or anchored to pos(): /\G/;
592  *   d) A start class: a real or synthetic character class which
593  *      represents which characters are legal at the start of the pattern;
594  *
595  * to either quickly reject the match, or to find the earliest position
596  * within the string at which the pattern might match, thus avoiding
597  * running the full NFA engine at those earlier locations, only to
598  * eventually fail and retry further along.
599  *
600  * Returns NULL if the pattern can't match, or returns the address within
601  * the string which is the earliest place the match could occur.
602  *
603  * The longest of the anchored and floating substrings is called 'check'
604  * and is checked first. The other is called 'other' and is checked
605  * second. The 'other' substring may not be present.  For example,
606  *
607  *    /(abc|xyz)ABC\d{0,3}DEFG/
608  *
609  * will have
610  *
611  *   check substr (float)    = "DEFG", offset 6..9 chars
612  *   other substr (anchored) = "ABC",  offset 3..3 chars
613  *   stclass = [ax]
614  *
615  * Be aware that during the course of this function, sometimes 'anchored'
616  * refers to a substring being anchored relative to the start of the
617  * pattern, and sometimes to the pattern itself being anchored relative to
618  * the string. For example:
619  *
620  *   /\dabc/:   "abc" is anchored to the pattern;
621  *   /^\dabc/:  "abc" is anchored to the pattern and the string;
622  *   /\d+abc/:  "abc" is anchored to neither the pattern nor the string;
623  *   /^\d+abc/: "abc" is anchored to neither the pattern nor the string,
624  *                    but the pattern is anchored to the string.
625  */
626 
627 char *
628 Perl_re_intuit_start(pTHX_
629                     REGEXP * const rx,
630                     SV *sv,
631                     const char * const strbeg,
632                     char *strpos,
633                     char *strend,
634                     const U32 flags,
635                     re_scream_pos_data *data)
636 {
637     struct regexp *const prog = ReANY(rx);
638     SSize_t start_shift = prog->check_offset_min;
639     /* Should be nonnegative! */
640     SSize_t end_shift   = 0;
641     /* current lowest pos in string where the regex can start matching */
642     char *rx_origin = strpos;
643     SV *check;
644     const bool utf8_target = (sv && SvUTF8(sv)) ? 1 : 0; /* if no sv we have to assume bytes */
645     U8   other_ix = 1 - prog->substrs->check_ix;
646     bool ml_anch = 0;
647     char *other_last = strpos;/* latest pos 'other' substr already checked to */
648     char *check_at = NULL;		/* check substr found at this pos */
649     const I32 multiline = prog->extflags & RXf_PMf_MULTILINE;
650     RXi_GET_DECL(prog,progi);
651     regmatch_info reginfo_buf;  /* create some info to pass to find_byclass */
652     regmatch_info *const reginfo = &reginfo_buf;
653     GET_RE_DEBUG_FLAGS_DECL;
654 
655     PERL_ARGS_ASSERT_RE_INTUIT_START;
656     PERL_UNUSED_ARG(flags);
657     PERL_UNUSED_ARG(data);
658 
659     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
660                 "Intuit: trying to determine minimum start position...\n"));
661 
662     /* for now, assume that all substr offsets are positive. If at some point
663      * in the future someone wants to do clever things with lookbehind and
664      * -ve offsets, they'll need to fix up any code in this function
665      * which uses these offsets. See the thread beginning
666      * <20140113145929.GF27210@iabyn.com>
667      */
668     assert(prog->substrs->data[0].min_offset >= 0);
669     assert(prog->substrs->data[0].max_offset >= 0);
670     assert(prog->substrs->data[1].min_offset >= 0);
671     assert(prog->substrs->data[1].max_offset >= 0);
672     assert(prog->substrs->data[2].min_offset >= 0);
673     assert(prog->substrs->data[2].max_offset >= 0);
674 
675     /* for now, assume that if both present, that the floating substring
676      * doesn't start before the anchored substring.
677      * If you break this assumption (e.g. doing better optimisations
678      * with lookahead/behind), then you'll need to audit the code in this
679      * function carefully first
680      */
681     assert(
682             ! (  (prog->anchored_utf8 || prog->anchored_substr)
683               && (prog->float_utf8    || prog->float_substr))
684            || (prog->float_min_offset >= prog->anchored_offset));
685 
686     /* byte rather than char calculation for efficiency. It fails
687      * to quickly reject some cases that can't match, but will reject
688      * them later after doing full char arithmetic */
689     if (prog->minlen > strend - strpos) {
690         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
691 			      "  String too short...\n"));
692 	goto fail;
693     }
694 
695     RX_MATCH_UTF8_set(rx,utf8_target);
696     reginfo->is_utf8_target = cBOOL(utf8_target);
697     reginfo->info_aux = NULL;
698     reginfo->strbeg = strbeg;
699     reginfo->strend = strend;
700     reginfo->is_utf8_pat = cBOOL(RX_UTF8(rx));
701     reginfo->intuit = 1;
702     /* not actually used within intuit, but zero for safety anyway */
703     reginfo->poscache_maxiter = 0;
704 
705     if (utf8_target) {
706 	if (!prog->check_utf8 && prog->check_substr)
707 	    to_utf8_substr(prog);
708 	check = prog->check_utf8;
709     } else {
710 	if (!prog->check_substr && prog->check_utf8) {
711 	    if (! to_byte_substr(prog)) {
712                 NON_UTF8_TARGET_BUT_UTF8_REQUIRED(fail);
713             }
714         }
715 	check = prog->check_substr;
716     }
717 
718     /* dump the various substring data */
719     DEBUG_OPTIMISE_MORE_r({
720         int i;
721         for (i=0; i<=2; i++) {
722             SV *sv = (utf8_target ? prog->substrs->data[i].utf8_substr
723                                   : prog->substrs->data[i].substr);
724             if (!sv)
725                 continue;
726 
727             Perl_re_printf( aTHX_
728                 "  substrs[%d]: min=%"IVdf" max=%"IVdf" end shift=%"IVdf
729                 " useful=%"IVdf" utf8=%d [%s]\n",
730                 i,
731                 (IV)prog->substrs->data[i].min_offset,
732                 (IV)prog->substrs->data[i].max_offset,
733                 (IV)prog->substrs->data[i].end_shift,
734                 BmUSEFUL(sv),
735                 utf8_target ? 1 : 0,
736                 SvPEEK(sv));
737         }
738     });
739 
740     if (prog->intflags & PREGf_ANCH) { /* Match at \G, beg-of-str or after \n */
741 
742         /* ml_anch: check after \n?
743          *
744          * A note about PREGf_IMPLICIT: on an un-anchored pattern beginning
745          * with /.*.../, these flags will have been added by the
746          * compiler:
747          *   /.*abc/, /.*abc/m:  PREGf_IMPLICIT | PREGf_ANCH_MBOL
748          *   /.*abc/s:           PREGf_IMPLICIT | PREGf_ANCH_SBOL
749          */
750 	ml_anch =      (prog->intflags & PREGf_ANCH_MBOL)
751                    && !(prog->intflags & PREGf_IMPLICIT);
752 
753 	if (!ml_anch && !(prog->intflags & PREGf_IMPLICIT)) {
754             /* we are only allowed to match at BOS or \G */
755 
756             /* trivially reject if there's a BOS anchor and we're not at BOS.
757              *
758              * Note that we don't try to do a similar quick reject for
759              * \G, since generally the caller will have calculated strpos
760              * based on pos() and gofs, so the string is already correctly
761              * anchored by definition; and handling the exceptions would
762              * be too fiddly (e.g. REXEC_IGNOREPOS).
763              */
764             if (   strpos != strbeg
765                 && (prog->intflags & PREGf_ANCH_SBOL))
766             {
767                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
768                                 "  Not at start...\n"));
769 	        goto fail;
770 	    }
771 
772             /* in the presence of an anchor, the anchored (relative to the
773              * start of the regex) substr must also be anchored relative
774              * to strpos. So quickly reject if substr isn't found there.
775              * This works for \G too, because the caller will already have
776              * subtracted gofs from pos, and gofs is the offset from the
777              * \G to the start of the regex. For example, in /.abc\Gdef/,
778              * where substr="abcdef", pos()=3, gofs=4, offset_min=1:
779              * caller will have set strpos=pos()-4; we look for the substr
780              * at position pos()-4+1, which lines up with the "a" */
781 
782 	    if (prog->check_offset_min == prog->check_offset_max) {
783 	        /* Substring at constant offset from beg-of-str... */
784 	        SSize_t slen = SvCUR(check);
785                 char *s = HOP3c(strpos, prog->check_offset_min, strend);
786 
787                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
788                     "  Looking for check substr at fixed offset %"IVdf"...\n",
789                     (IV)prog->check_offset_min));
790 
791 	        if (SvTAIL(check)) {
792                     /* In this case, the regex is anchored at the end too.
793                      * Unless it's a multiline match, the lengths must match
794                      * exactly, give or take a \n.  NB: slen >= 1 since
795                      * the last char of check is \n */
796 		    if (!multiline
797                         && (   strend - s > slen
798                             || strend - s < slen - 1
799                             || (strend - s == slen && strend[-1] != '\n')))
800                     {
801                         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
802                                             "  String too long...\n"));
803                         goto fail_finish;
804                     }
805                     /* Now should match s[0..slen-2] */
806                     slen--;
807                 }
808                 if (slen && (*SvPVX_const(check) != *s
809                     || (slen > 1 && memNE(SvPVX_const(check), s, slen))))
810                 {
811                     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
812                                     "  String not equal...\n"));
813                     goto fail_finish;
814                 }
815 
816                 check_at = s;
817                 goto success_at_start;
818 	    }
819 	}
820     }
821 
822     end_shift = prog->check_end_shift;
823 
824 #ifdef DEBUGGING	/* 7/99: reports of failure (with the older version) */
825     if (end_shift < 0)
826 	Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
827 		   (IV)end_shift, RX_PRECOMP(prog));
828 #endif
829 
830   restart:
831 
832     /* This is the (re)entry point of the main loop in this function.
833      * The goal of this loop is to:
834      * 1) find the "check" substring in the region rx_origin..strend
835      *    (adjusted by start_shift / end_shift). If not found, reject
836      *    immediately.
837      * 2) If it exists, look for the "other" substr too if defined; for
838      *    example, if the check substr maps to the anchored substr, then
839      *    check the floating substr, and vice-versa. If not found, go
840      *    back to (1) with rx_origin suitably incremented.
841      * 3) If we find an rx_origin position that doesn't contradict
842      *    either of the substrings, then check the possible additional
843      *    constraints on rx_origin of /^.../m or a known start class.
844      *    If these fail, then depending on which constraints fail, jump
845      *    back to here, or to various other re-entry points further along
846      *    that skip some of the first steps.
847      * 4) If we pass all those tests, update the BmUSEFUL() count on the
848      *    substring. If the start position was determined to be at the
849      *    beginning of the string  - so, not rejected, but not optimised,
850      *    since we have to run regmatch from position 0 - decrement the
851      *    BmUSEFUL() count. Otherwise increment it.
852      */
853 
854 
855     /* first, look for the 'check' substring */
856 
857     {
858         U8* start_point;
859         U8* end_point;
860 
861         DEBUG_OPTIMISE_MORE_r({
862             Perl_re_printf( aTHX_
863                 "  At restart: rx_origin=%"IVdf" Check offset min: %"IVdf
864                 " Start shift: %"IVdf" End shift %"IVdf
865                 " Real end Shift: %"IVdf"\n",
866                 (IV)(rx_origin - strbeg),
867                 (IV)prog->check_offset_min,
868                 (IV)start_shift,
869                 (IV)end_shift,
870                 (IV)prog->check_end_shift);
871         });
872 
873         end_point = HOP3(strend, -end_shift, strbeg);
874         start_point = HOPMAYBE3(rx_origin, start_shift, end_point);
875         if (!start_point)
876             goto fail_finish;
877 
878 
879         /* If the regex is absolutely anchored to either the start of the
880          * string (SBOL) or to pos() (ANCH_GPOS), then
881          * check_offset_max represents an upper bound on the string where
882          * the substr could start. For the ANCH_GPOS case, we assume that
883          * the caller of intuit will have already set strpos to
884          * pos()-gofs, so in this case strpos + offset_max will still be
885          * an upper bound on the substr.
886          */
887         if (!ml_anch
888             && prog->intflags & PREGf_ANCH
889             && prog->check_offset_max != SSize_t_MAX)
890         {
891             SSize_t len = SvCUR(check) - !!SvTAIL(check);
892             const char * const anchor =
893                         (prog->intflags & PREGf_ANCH_GPOS ? strpos : strbeg);
894 
895             /* do a bytes rather than chars comparison. It's conservative;
896              * so it skips doing the HOP if the result can't possibly end
897              * up earlier than the old value of end_point.
898              */
899             if ((char*)end_point - anchor > prog->check_offset_max) {
900                 end_point = HOP3lim((U8*)anchor,
901                                 prog->check_offset_max,
902                                 end_point -len)
903                             + len;
904             }
905         }
906 
907 	check_at = fbm_instr( start_point, end_point,
908 		      check, multiline ? FBMrf_MULTILINE : 0);
909 
910         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
911             "  doing 'check' fbm scan, [%"IVdf"..%"IVdf"] gave %"IVdf"\n",
912             (IV)((char*)start_point - strbeg),
913             (IV)((char*)end_point   - strbeg),
914             (IV)(check_at ? check_at - strbeg : -1)
915         ));
916 
917         /* Update the count-of-usability, remove useless subpatterns,
918             unshift s.  */
919 
920         DEBUG_EXECUTE_r({
921             RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
922                 SvPVX_const(check), RE_SV_DUMPLEN(check), 30);
923             Perl_re_printf( aTHX_  "  %s %s substr %s%s%s",
924                               (check_at ? "Found" : "Did not find"),
925                 (check == (utf8_target ? prog->anchored_utf8 : prog->anchored_substr)
926                     ? "anchored" : "floating"),
927                 quoted,
928                 RE_SV_TAIL(check),
929                 (check_at ? " at offset " : "...\n") );
930         });
931 
932         if (!check_at)
933             goto fail_finish;
934         /* set rx_origin to the minimum position where the regex could start
935          * matching, given the constraint of the just-matched check substring.
936          * But don't set it lower than previously.
937          */
938 
939         if (check_at - rx_origin > prog->check_offset_max)
940             rx_origin = HOP3c(check_at, -prog->check_offset_max, rx_origin);
941         /* Finish the diagnostic message */
942         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
943             "%ld (rx_origin now %"IVdf")...\n",
944             (long)(check_at - strbeg),
945             (IV)(rx_origin - strbeg)
946         ));
947     }
948 
949 
950     /* now look for the 'other' substring if defined */
951 
952     if (utf8_target ? prog->substrs->data[other_ix].utf8_substr
953                     : prog->substrs->data[other_ix].substr)
954     {
955 	/* Take into account the "other" substring. */
956         char *last, *last1;
957         char *s;
958         SV* must;
959         struct reg_substr_datum *other;
960 
961       do_other_substr:
962         other = &prog->substrs->data[other_ix];
963 
964         /* if "other" is anchored:
965          * we've previously found a floating substr starting at check_at.
966          * This means that the regex origin must lie somewhere
967          * between min (rx_origin): HOP3(check_at, -check_offset_max)
968          * and max:                 HOP3(check_at, -check_offset_min)
969          * (except that min will be >= strpos)
970          * So the fixed  substr must lie somewhere between
971          *  HOP3(min, anchored_offset)
972          *  HOP3(max, anchored_offset) + SvCUR(substr)
973          */
974 
975         /* if "other" is floating
976          * Calculate last1, the absolute latest point where the
977          * floating substr could start in the string, ignoring any
978          * constraints from the earlier fixed match. It is calculated
979          * as follows:
980          *
981          * strend - prog->minlen (in chars) is the absolute latest
982          * position within the string where the origin of the regex
983          * could appear. The latest start point for the floating
984          * substr is float_min_offset(*) on from the start of the
985          * regex.  last1 simply combines thee two offsets.
986          *
987          * (*) You might think the latest start point should be
988          * float_max_offset from the regex origin, and technically
989          * you'd be correct. However, consider
990          *    /a\d{2,4}bcd\w/
991          * Here, float min, max are 3,5 and minlen is 7.
992          * This can match either
993          *    /a\d\dbcd\w/
994          *    /a\d\d\dbcd\w/
995          *    /a\d\d\d\dbcd\w/
996          * In the first case, the regex matches minlen chars; in the
997          * second, minlen+1, in the third, minlen+2.
998          * In the first case, the floating offset is 3 (which equals
999          * float_min), in the second, 4, and in the third, 5 (which
1000          * equals float_max). In all cases, the floating string bcd
1001          * can never start more than 4 chars from the end of the
1002          * string, which equals minlen - float_min. As the substring
1003          * starts to match more than float_min from the start of the
1004          * regex, it makes the regex match more than minlen chars,
1005          * and the two cancel each other out. So we can always use
1006          * float_min - minlen, rather than float_max - minlen for the
1007          * latest position in the string.
1008          *
1009          * Note that -minlen + float_min_offset is equivalent (AFAIKT)
1010          * to CHR_SVLEN(must) - !!SvTAIL(must) + prog->float_end_shift
1011          */
1012 
1013         assert(prog->minlen >= other->min_offset);
1014         last1 = HOP3c(strend,
1015                         other->min_offset - prog->minlen, strbeg);
1016 
1017         if (other_ix) {/* i.e. if (other-is-float) */
1018             /* last is the latest point where the floating substr could
1019              * start, *given* any constraints from the earlier fixed
1020              * match. This constraint is that the floating string starts
1021              * <= float_max_offset chars from the regex origin (rx_origin).
1022              * If this value is less than last1, use it instead.
1023              */
1024             assert(rx_origin <= last1);
1025             last =
1026                 /* this condition handles the offset==infinity case, and
1027                  * is a short-cut otherwise. Although it's comparing a
1028                  * byte offset to a char length, it does so in a safe way,
1029                  * since 1 char always occupies 1 or more bytes,
1030                  * so if a string range is  (last1 - rx_origin) bytes,
1031                  * it will be less than or equal to  (last1 - rx_origin)
1032                  * chars; meaning it errs towards doing the accurate HOP3
1033                  * rather than just using last1 as a short-cut */
1034                 (last1 - rx_origin) < other->max_offset
1035                     ? last1
1036                     : (char*)HOP3lim(rx_origin, other->max_offset, last1);
1037         }
1038         else {
1039             assert(strpos + start_shift <= check_at);
1040             last = HOP4c(check_at, other->min_offset - start_shift,
1041                         strbeg, strend);
1042         }
1043 
1044         s = HOP3c(rx_origin, other->min_offset, strend);
1045         if (s < other_last)	/* These positions already checked */
1046             s = other_last;
1047 
1048         must = utf8_target ? other->utf8_substr : other->substr;
1049         assert(SvPOK(must));
1050         {
1051             char *from = s;
1052             char *to   = last + SvCUR(must) - (SvTAIL(must)!=0);
1053 
1054             if (from > to) {
1055                 s = NULL;
1056                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1057                     "  skipping 'other' fbm scan: %"IVdf" > %"IVdf"\n",
1058                     (IV)(from - strbeg),
1059                     (IV)(to   - strbeg)
1060                 ));
1061             }
1062             else {
1063                 s = fbm_instr(
1064                     (unsigned char*)from,
1065                     (unsigned char*)to,
1066                     must,
1067                     multiline ? FBMrf_MULTILINE : 0
1068                 );
1069                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1070                     "  doing 'other' fbm scan, [%"IVdf"..%"IVdf"] gave %"IVdf"\n",
1071                     (IV)(from - strbeg),
1072                     (IV)(to   - strbeg),
1073                     (IV)(s ? s - strbeg : -1)
1074                 ));
1075             }
1076         }
1077 
1078         DEBUG_EXECUTE_r({
1079             RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
1080                 SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
1081             Perl_re_printf( aTHX_  "  %s %s substr %s%s",
1082                 s ? "Found" : "Contradicts",
1083                 other_ix ? "floating" : "anchored",
1084                 quoted, RE_SV_TAIL(must));
1085         });
1086 
1087 
1088         if (!s) {
1089             /* last1 is latest possible substr location. If we didn't
1090              * find it before there, we never will */
1091             if (last >= last1) {
1092                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1093                                         "; giving up...\n"));
1094                 goto fail_finish;
1095             }
1096 
1097             /* try to find the check substr again at a later
1098              * position. Maybe next time we'll find the "other" substr
1099              * in range too */
1100             other_last = HOP3c(last, 1, strend) /* highest failure */;
1101             rx_origin =
1102                 other_ix /* i.e. if other-is-float */
1103                     ? HOP3c(rx_origin, 1, strend)
1104                     : HOP4c(last, 1 - other->min_offset, strbeg, strend);
1105             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1106                 "; about to retry %s at offset %ld (rx_origin now %"IVdf")...\n",
1107                 (other_ix ? "floating" : "anchored"),
1108                 (long)(HOP3c(check_at, 1, strend) - strbeg),
1109                 (IV)(rx_origin - strbeg)
1110             ));
1111             goto restart;
1112         }
1113         else {
1114             if (other_ix) { /* if (other-is-float) */
1115                 /* other_last is set to s, not s+1, since its possible for
1116                  * a floating substr to fail first time, then succeed
1117                  * second time at the same floating position; e.g.:
1118                  *     "-AB--AABZ" =~ /\wAB\d*Z/
1119                  * The first time round, anchored and float match at
1120                  * "-(AB)--AAB(Z)" then fail on the initial \w character
1121                  * class. Second time round, they match at "-AB--A(AB)(Z)".
1122                  */
1123                 other_last = s;
1124             }
1125             else {
1126                 rx_origin = HOP3c(s, -other->min_offset, strbeg);
1127                 other_last = HOP3c(s, 1, strend);
1128             }
1129             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1130                 " at offset %ld (rx_origin now %"IVdf")...\n",
1131                   (long)(s - strbeg),
1132                 (IV)(rx_origin - strbeg)
1133               ));
1134 
1135         }
1136     }
1137     else {
1138         DEBUG_OPTIMISE_MORE_r(
1139             Perl_re_printf( aTHX_
1140                 "  Check-only match: offset min:%"IVdf" max:%"IVdf
1141                 " check_at:%"IVdf" rx_origin:%"IVdf" rx_origin-check_at:%"IVdf
1142                 " strend:%"IVdf"\n",
1143                 (IV)prog->check_offset_min,
1144                 (IV)prog->check_offset_max,
1145                 (IV)(check_at-strbeg),
1146                 (IV)(rx_origin-strbeg),
1147                 (IV)(rx_origin-check_at),
1148                 (IV)(strend-strbeg)
1149             )
1150         );
1151     }
1152 
1153   postprocess_substr_matches:
1154 
1155     /* handle the extra constraint of /^.../m if present */
1156 
1157     if (ml_anch && rx_origin != strbeg && rx_origin[-1] != '\n') {
1158         char *s;
1159 
1160         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1161                         "  looking for /^/m anchor"));
1162 
1163         /* we have failed the constraint of a \n before rx_origin.
1164          * Find the next \n, if any, even if it's beyond the current
1165          * anchored and/or floating substrings. Whether we should be
1166          * scanning ahead for the next \n or the next substr is debatable.
1167          * On the one hand you'd expect rare substrings to appear less
1168          * often than \n's. On the other hand, searching for \n means
1169          * we're effectively flipping between check_substr and "\n" on each
1170          * iteration as the current "rarest" string candidate, which
1171          * means for example that we'll quickly reject the whole string if
1172          * hasn't got a \n, rather than trying every substr position
1173          * first
1174          */
1175 
1176         s = HOP3c(strend, - prog->minlen, strpos);
1177         if (s <= rx_origin ||
1178             ! ( rx_origin = (char *)memchr(rx_origin, '\n', s - rx_origin)))
1179         {
1180             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1181                             "  Did not find /%s^%s/m...\n",
1182                             PL_colors[0], PL_colors[1]));
1183             goto fail_finish;
1184         }
1185 
1186         /* earliest possible origin is 1 char after the \n.
1187          * (since *rx_origin == '\n', it's safe to ++ here rather than
1188          * HOP(rx_origin, 1)) */
1189         rx_origin++;
1190 
1191         if (prog->substrs->check_ix == 0  /* check is anchored */
1192             || rx_origin >= HOP3c(check_at,  - prog->check_offset_min, strpos))
1193         {
1194             /* Position contradicts check-string; either because
1195              * check was anchored (and thus has no wiggle room),
1196              * or check was float and rx_origin is above the float range */
1197             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1198                 "  Found /%s^%s/m, about to restart lookup for check-string with rx_origin %ld...\n",
1199                 PL_colors[0], PL_colors[1], (long)(rx_origin - strbeg)));
1200             goto restart;
1201         }
1202 
1203         /* if we get here, the check substr must have been float,
1204          * is in range, and we may or may not have had an anchored
1205          * "other" substr which still contradicts */
1206         assert(prog->substrs->check_ix); /* check is float */
1207 
1208         if (utf8_target ? prog->anchored_utf8 : prog->anchored_substr) {
1209             /* whoops, the anchored "other" substr exists, so we still
1210              * contradict. On the other hand, the float "check" substr
1211              * didn't contradict, so just retry the anchored "other"
1212              * substr */
1213             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1214                 "  Found /%s^%s/m, rescanning for anchored from offset %"IVdf" (rx_origin now %"IVdf")...\n",
1215                 PL_colors[0], PL_colors[1],
1216                 (IV)(rx_origin - strbeg + prog->anchored_offset),
1217                 (IV)(rx_origin - strbeg)
1218             ));
1219             goto do_other_substr;
1220         }
1221 
1222         /* success: we don't contradict the found floating substring
1223          * (and there's no anchored substr). */
1224         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1225             "  Found /%s^%s/m with rx_origin %ld...\n",
1226             PL_colors[0], PL_colors[1], (long)(rx_origin - strbeg)));
1227     }
1228     else {
1229         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1230             "  (multiline anchor test skipped)\n"));
1231     }
1232 
1233   success_at_start:
1234 
1235 
1236     /* if we have a starting character class, then test that extra constraint.
1237      * (trie stclasses are too expensive to use here, we are better off to
1238      * leave it to regmatch itself) */
1239 
1240     if (progi->regstclass && PL_regkind[OP(progi->regstclass)]!=TRIE) {
1241         const U8* const str = (U8*)STRING(progi->regstclass);
1242 
1243         /* XXX this value could be pre-computed */
1244         const int cl_l = (PL_regkind[OP(progi->regstclass)] == EXACT
1245 		    ?  (reginfo->is_utf8_pat
1246                         ? utf8_distance(str + STR_LEN(progi->regstclass), str)
1247                         : STR_LEN(progi->regstclass))
1248 		    : 1);
1249 	char * endpos;
1250         char *s;
1251         /* latest pos that a matching float substr constrains rx start to */
1252         char *rx_max_float = NULL;
1253 
1254         /* if the current rx_origin is anchored, either by satisfying an
1255          * anchored substring constraint, or a /^.../m constraint, then we
1256          * can reject the current origin if the start class isn't found
1257          * at the current position. If we have a float-only match, then
1258          * rx_origin is constrained to a range; so look for the start class
1259          * in that range. if neither, then look for the start class in the
1260          * whole rest of the string */
1261 
1262         /* XXX DAPM it's not clear what the minlen test is for, and why
1263          * it's not used in the floating case. Nothing in the test suite
1264          * causes minlen == 0 here. See <20140313134639.GS12844@iabyn.com>.
1265          * Here are some old comments, which may or may not be correct:
1266          *
1267 	 *   minlen == 0 is possible if regstclass is \b or \B,
1268 	 *   and the fixed substr is ''$.
1269          *   Since minlen is already taken into account, rx_origin+1 is
1270          *   before strend; accidentally, minlen >= 1 guaranties no false
1271          *   positives at rx_origin + 1 even for \b or \B.  But (minlen? 1 :
1272          *   0) below assumes that regstclass does not come from lookahead...
1273 	 *   If regstclass takes bytelength more than 1: If charlength==1, OK.
1274          *   This leaves EXACTF-ish only, which are dealt with in
1275          *   find_byclass().
1276          */
1277 
1278 	if (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
1279             endpos= HOP3c(rx_origin, (prog->minlen ? cl_l : 0), strend);
1280         else if (prog->float_substr || prog->float_utf8) {
1281 	    rx_max_float = HOP3c(check_at, -start_shift, strbeg);
1282 	    endpos= HOP3c(rx_max_float, cl_l, strend);
1283         }
1284         else
1285             endpos= strend;
1286 
1287         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1288             "  looking for class: start_shift: %"IVdf" check_at: %"IVdf
1289             " rx_origin: %"IVdf" endpos: %"IVdf"\n",
1290               (IV)start_shift, (IV)(check_at - strbeg),
1291               (IV)(rx_origin - strbeg), (IV)(endpos - strbeg)));
1292 
1293         s = find_byclass(prog, progi->regstclass, rx_origin, endpos,
1294                             reginfo);
1295 	if (!s) {
1296 	    if (endpos == strend) {
1297                 DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1298 				"  Could not match STCLASS...\n") );
1299 		goto fail;
1300 	    }
1301             DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1302                                "  This position contradicts STCLASS...\n") );
1303             if ((prog->intflags & PREGf_ANCH) && !ml_anch
1304                         && !(prog->intflags & PREGf_IMPLICIT))
1305 		goto fail;
1306 
1307 	    /* Contradict one of substrings */
1308 	    if (prog->anchored_substr || prog->anchored_utf8) {
1309                 if (prog->substrs->check_ix == 1) { /* check is float */
1310                     /* Have both, check_string is floating */
1311                     assert(rx_origin + start_shift <= check_at);
1312                     if (rx_origin + start_shift != check_at) {
1313                         /* not at latest position float substr could match:
1314                          * Recheck anchored substring, but not floating.
1315                          * The condition above is in bytes rather than
1316                          * chars for efficiency. It's conservative, in
1317                          * that it errs on the side of doing 'goto
1318                          * do_other_substr'. In this case, at worst,
1319                          * an extra anchored search may get done, but in
1320                          * practice the extra fbm_instr() is likely to
1321                          * get skipped anyway. */
1322                         DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1323                             "  about to retry anchored at offset %ld (rx_origin now %"IVdf")...\n",
1324                             (long)(other_last - strbeg),
1325                             (IV)(rx_origin - strbeg)
1326                         ));
1327                         goto do_other_substr;
1328                     }
1329                 }
1330             }
1331 	    else {
1332                 /* float-only */
1333 
1334                 if (ml_anch) {
1335                     /* In the presence of ml_anch, we might be able to
1336                      * find another \n without breaking the current float
1337                      * constraint. */
1338 
1339                     /* strictly speaking this should be HOP3c(..., 1, ...),
1340                      * but since we goto a block of code that's going to
1341                      * search for the next \n if any, its safe here */
1342                     rx_origin++;
1343                     DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1344                               "  about to look for /%s^%s/m starting at rx_origin %ld...\n",
1345                               PL_colors[0], PL_colors[1],
1346                               (long)(rx_origin - strbeg)) );
1347                     goto postprocess_substr_matches;
1348                 }
1349 
1350                 /* strictly speaking this can never be true; but might
1351                  * be if we ever allow intuit without substrings */
1352                 if (!(utf8_target ? prog->float_utf8 : prog->float_substr))
1353                     goto fail;
1354 
1355                 rx_origin = rx_max_float;
1356             }
1357 
1358             /* at this point, any matching substrings have been
1359              * contradicted. Start again... */
1360 
1361             rx_origin = HOP3c(rx_origin, 1, strend);
1362 
1363             /* uses bytes rather than char calculations for efficiency.
1364              * It's conservative: it errs on the side of doing 'goto restart',
1365              * where there is code that does a proper char-based test */
1366             if (rx_origin + start_shift + end_shift > strend) {
1367                 DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1368                                        "  Could not match STCLASS...\n") );
1369                 goto fail;
1370             }
1371             DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
1372                 "  about to look for %s substr starting at offset %ld (rx_origin now %"IVdf")...\n",
1373                 (prog->substrs->check_ix ? "floating" : "anchored"),
1374                 (long)(rx_origin + start_shift - strbeg),
1375                 (IV)(rx_origin - strbeg)
1376             ));
1377             goto restart;
1378 	}
1379 
1380         /* Success !!! */
1381 
1382 	if (rx_origin != s) {
1383             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1384 			"  By STCLASS: moving %ld --> %ld\n",
1385                                   (long)(rx_origin - strbeg), (long)(s - strbeg))
1386                    );
1387         }
1388         else {
1389             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1390                                   "  Does not contradict STCLASS...\n");
1391                    );
1392         }
1393     }
1394 
1395     /* Decide whether using the substrings helped */
1396 
1397     if (rx_origin != strpos) {
1398 	/* Fixed substring is found far enough so that the match
1399 	   cannot start at strpos. */
1400 
1401         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "  try at offset...\n"));
1402 	++BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr);	/* hooray/5 */
1403     }
1404     else {
1405         /* The found rx_origin position does not prohibit matching at
1406          * strpos, so calling intuit didn't gain us anything. Decrement
1407          * the BmUSEFUL() count on the check substring, and if we reach
1408          * zero, free it.  */
1409 	if (!(prog->intflags & PREGf_NAUGHTY)
1410 	    && (utf8_target ? (
1411 		prog->check_utf8		/* Could be deleted already */
1412 		&& --BmUSEFUL(prog->check_utf8) < 0
1413 		&& (prog->check_utf8 == prog->float_utf8)
1414 	    ) : (
1415 		prog->check_substr		/* Could be deleted already */
1416 		&& --BmUSEFUL(prog->check_substr) < 0
1417 		&& (prog->check_substr == prog->float_substr)
1418 	    )))
1419 	{
1420 	    /* If flags & SOMETHING - do not do it many times on the same match */
1421             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "  ... Disabling check substring...\n"));
1422 	    /* XXX Does the destruction order has to change with utf8_target? */
1423 	    SvREFCNT_dec(utf8_target ? prog->check_utf8 : prog->check_substr);
1424 	    SvREFCNT_dec(utf8_target ? prog->check_substr : prog->check_utf8);
1425 	    prog->check_substr = prog->check_utf8 = NULL;	/* disable */
1426 	    prog->float_substr = prog->float_utf8 = NULL;	/* clear */
1427 	    check = NULL;			/* abort */
1428 	    /* XXXX This is a remnant of the old implementation.  It
1429 	            looks wasteful, since now INTUIT can use many
1430 	            other heuristics. */
1431 	    prog->extflags &= ~RXf_USE_INTUIT;
1432 	}
1433     }
1434 
1435     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
1436             "Intuit: %sSuccessfully guessed:%s match at offset %ld\n",
1437              PL_colors[4], PL_colors[5], (long)(rx_origin - strbeg)) );
1438 
1439     return rx_origin;
1440 
1441   fail_finish:				/* Substring not found */
1442     if (prog->check_substr || prog->check_utf8)		/* could be removed already */
1443 	BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr) += 5; /* hooray */
1444   fail:
1445     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "%sMatch rejected by optimizer%s\n",
1446 			  PL_colors[4], PL_colors[5]));
1447     return NULL;
1448 }
1449 
1450 
1451 #define DECL_TRIE_TYPE(scan) \
1452     const enum { trie_plain, trie_utf8, trie_utf8_fold, trie_latin_utf8_fold,       \
1453                  trie_utf8_exactfa_fold, trie_latin_utf8_exactfa_fold,              \
1454                  trie_utf8l, trie_flu8 }                                            \
1455                     trie_type = ((scan->flags == EXACT)                             \
1456                                  ? (utf8_target ? trie_utf8 : trie_plain)           \
1457                                  : (scan->flags == EXACTL)                          \
1458                                     ? (utf8_target ? trie_utf8l : trie_plain)       \
1459                                     : (scan->flags == EXACTFA)                      \
1460                                       ? (utf8_target                                \
1461                                          ? trie_utf8_exactfa_fold                   \
1462                                          : trie_latin_utf8_exactfa_fold)            \
1463                                       : (scan->flags == EXACTFLU8                   \
1464                                          ? trie_flu8                                \
1465                                          : (utf8_target                             \
1466                                            ? trie_utf8_fold                         \
1467                                            :   trie_latin_utf8_fold)))
1468 
1469 #define REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, uscan, len, uvc, charid, foldlen, foldbuf, uniflags) \
1470 STMT_START {                                                                        \
1471     STRLEN skiplen;                                                                 \
1472     U8 flags = FOLD_FLAGS_FULL;                                                     \
1473     switch (trie_type) {                                                            \
1474     case trie_flu8:                                                                 \
1475         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;                                         \
1476         if (utf8_target && UTF8_IS_ABOVE_LATIN1(*uc)) {                             \
1477             _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(uc, uc + UTF8SKIP(uc));          \
1478         }                                                                           \
1479         goto do_trie_utf8_fold;                                                     \
1480     case trie_utf8_exactfa_fold:                                                    \
1481         flags |= FOLD_FLAGS_NOMIX_ASCII;                                            \
1482         /* FALLTHROUGH */                                                           \
1483     case trie_utf8_fold:                                                            \
1484       do_trie_utf8_fold:                                                            \
1485         if ( foldlen>0 ) {                                                          \
1486             uvc = utf8n_to_uvchr( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
1487             foldlen -= len;                                                         \
1488             uscan += len;                                                           \
1489             len=0;                                                                  \
1490         } else {                                                                    \
1491             uvc = _to_utf8_fold_flags( (const U8*) uc, foldbuf, &foldlen, flags);   \
1492             len = UTF8SKIP(uc);                                                     \
1493             skiplen = UVCHR_SKIP( uvc );                                            \
1494             foldlen -= skiplen;                                                     \
1495             uscan = foldbuf + skiplen;                                              \
1496         }                                                                           \
1497         break;                                                                      \
1498     case trie_latin_utf8_exactfa_fold:                                              \
1499         flags |= FOLD_FLAGS_NOMIX_ASCII;                                            \
1500         /* FALLTHROUGH */                                                           \
1501     case trie_latin_utf8_fold:                                                      \
1502         if ( foldlen>0 ) {                                                          \
1503             uvc = utf8n_to_uvchr( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
1504             foldlen -= len;                                                         \
1505             uscan += len;                                                           \
1506             len=0;                                                                  \
1507         } else {                                                                    \
1508             len = 1;                                                                \
1509             uvc = _to_fold_latin1( (U8) *uc, foldbuf, &foldlen, flags);             \
1510             skiplen = UVCHR_SKIP( uvc );                                            \
1511             foldlen -= skiplen;                                                     \
1512             uscan = foldbuf + skiplen;                                              \
1513         }                                                                           \
1514         break;                                                                      \
1515     case trie_utf8l:                                                                \
1516         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;                                         \
1517         if (utf8_target && UTF8_IS_ABOVE_LATIN1(*uc)) {                             \
1518             _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(uc, uc + UTF8SKIP(uc));          \
1519         }                                                                           \
1520         /* FALLTHROUGH */                                                           \
1521     case trie_utf8:                                                                 \
1522         uvc = utf8n_to_uvchr( (const U8*) uc, UTF8_MAXLEN, &len, uniflags );        \
1523         break;                                                                      \
1524     case trie_plain:                                                                \
1525         uvc = (UV)*uc;                                                              \
1526         len = 1;                                                                    \
1527     }                                                                               \
1528     if (uvc < 256) {                                                                \
1529         charid = trie->charmap[ uvc ];                                              \
1530     }                                                                               \
1531     else {                                                                          \
1532         charid = 0;                                                                 \
1533         if (widecharmap) {                                                          \
1534             SV** const svpp = hv_fetch(widecharmap,                                 \
1535                         (char*)&uvc, sizeof(UV), 0);                                \
1536             if (svpp)                                                               \
1537                 charid = (U16)SvIV(*svpp);                                          \
1538         }                                                                           \
1539     }                                                                               \
1540 } STMT_END
1541 
1542 #define DUMP_EXEC_POS(li,s,doutf8,depth)                    \
1543     dump_exec_pos(li,s,(reginfo->strend),(reginfo->strbeg), \
1544                 startpos, doutf8, depth)
1545 
1546 #define REXEC_FBC_EXACTISH_SCAN(COND)                     \
1547 STMT_START {                                              \
1548     while (s <= e) {                                      \
1549 	if ( (COND)                                       \
1550 	     && (ln == 1 || folder(s, pat_string, ln))    \
1551 	     && (reginfo->intuit || regtry(reginfo, &s)) )\
1552 	    goto got_it;                                  \
1553 	s++;                                              \
1554     }                                                     \
1555 } STMT_END
1556 
1557 #define REXEC_FBC_UTF8_SCAN(CODE)                     \
1558 STMT_START {                                          \
1559     while (s < strend) {                              \
1560 	CODE                                          \
1561 	s += UTF8SKIP(s);                             \
1562     }                                                 \
1563 } STMT_END
1564 
1565 #define REXEC_FBC_SCAN(CODE)                          \
1566 STMT_START {                                          \
1567     while (s < strend) {                              \
1568 	CODE                                          \
1569 	s++;                                          \
1570     }                                                 \
1571 } STMT_END
1572 
1573 #define REXEC_FBC_UTF8_CLASS_SCAN(COND)                        \
1574 REXEC_FBC_UTF8_SCAN( /* Loops while (s < strend) */            \
1575     if (COND) {                                                \
1576 	if (tmp && (reginfo->intuit || regtry(reginfo, &s)))   \
1577 	    goto got_it;                                       \
1578 	else                                                   \
1579 	    tmp = doevery;                                     \
1580     }                                                          \
1581     else                                                       \
1582 	tmp = 1;                                               \
1583 )
1584 
1585 #define REXEC_FBC_CLASS_SCAN(COND)                             \
1586 REXEC_FBC_SCAN( /* Loops while (s < strend) */                 \
1587     if (COND) {                                                \
1588 	if (tmp && (reginfo->intuit || regtry(reginfo, &s)))   \
1589 	    goto got_it;                                       \
1590 	else                                                   \
1591 	    tmp = doevery;                                     \
1592     }                                                          \
1593     else                                                       \
1594 	tmp = 1;                                               \
1595 )
1596 
1597 #define REXEC_FBC_CSCAN(CONDUTF8,COND)                         \
1598     if (utf8_target) {                                         \
1599 	REXEC_FBC_UTF8_CLASS_SCAN(CONDUTF8);                   \
1600     }                                                          \
1601     else {                                                     \
1602 	REXEC_FBC_CLASS_SCAN(COND);                            \
1603     }
1604 
1605 /* The three macros below are slightly different versions of the same logic.
1606  *
1607  * The first is for /a and /aa when the target string is UTF-8.  This can only
1608  * match ascii, but it must advance based on UTF-8.   The other two handle the
1609  * non-UTF-8 and the more generic UTF-8 cases.   In all three, we are looking
1610  * for the boundary (or non-boundary) between a word and non-word character.
1611  * The utf8 and non-utf8 cases have the same logic, but the details must be
1612  * different.  Find the "wordness" of the character just prior to this one, and
1613  * compare it with the wordness of this one.  If they differ, we have a
1614  * boundary.  At the beginning of the string, pretend that the previous
1615  * character was a new-line.
1616  *
1617  * All these macros uncleanly have side-effects with each other and outside
1618  * variables.  So far it's been too much trouble to clean-up
1619  *
1620  * TEST_NON_UTF8 is the macro or function to call to test if its byte input is
1621  *               a word character or not.
1622  * IF_SUCCESS    is code to do if it finds that we are at a boundary between
1623  *               word/non-word
1624  * IF_FAIL       is code to do if we aren't at a boundary between word/non-word
1625  *
1626  * Exactly one of the two IF_FOO parameters is a no-op, depending on whether we
1627  * are looking for a boundary or for a non-boundary.  If we are looking for a
1628  * boundary, we want IF_FAIL to be the no-op, and for IF_SUCCESS to go out and
1629  * see if this tentative match actually works, and if so, to quit the loop
1630  * here.  And vice-versa if we are looking for a non-boundary.
1631  *
1632  * 'tmp' below in the next three macros in the REXEC_FBC_SCAN and
1633  * REXEC_FBC_UTF8_SCAN loops is a loop invariant, a bool giving the return of
1634  * TEST_NON_UTF8(s-1).  To see this, note that that's what it is defined to be
1635  * at entry to the loop, and to get to the IF_FAIL branch, tmp must equal
1636  * TEST_NON_UTF8(s), and in the opposite branch, IF_SUCCESS, tmp is that
1637  * complement.  But in that branch we complement tmp, meaning that at the
1638  * bottom of the loop tmp is always going to be equal to TEST_NON_UTF8(s),
1639  * which means at the top of the loop in the next iteration, it is
1640  * TEST_NON_UTF8(s-1) */
1641 #define FBC_UTF8_A(TEST_NON_UTF8, IF_SUCCESS, IF_FAIL)                         \
1642     tmp = (s != reginfo->strbeg) ? UCHARAT(s - 1) : '\n';                      \
1643     tmp = TEST_NON_UTF8(tmp);                                                  \
1644     REXEC_FBC_UTF8_SCAN( /* advances s while s < strend */                     \
1645         if (tmp == ! TEST_NON_UTF8((U8) *s)) {                                 \
1646             tmp = !tmp;                                                        \
1647             IF_SUCCESS; /* Is a boundary if values for s-1 and s differ */     \
1648         }                                                                      \
1649         else {                                                                 \
1650             IF_FAIL;                                                           \
1651         }                                                                      \
1652     );                                                                         \
1653 
1654 /* Like FBC_UTF8_A, but TEST_UV is a macro which takes a UV as its input, and
1655  * TEST_UTF8 is a macro that for the same input code points returns identically
1656  * to TEST_UV, but takes a pointer to a UTF-8 encoded string instead */
1657 #define FBC_UTF8(TEST_UV, TEST_UTF8, IF_SUCCESS, IF_FAIL)                      \
1658     if (s == reginfo->strbeg) {                                                \
1659         tmp = '\n';                                                            \
1660     }                                                                          \
1661     else { /* Back-up to the start of the previous character */                \
1662         U8 * const r = reghop3((U8*)s, -1, (U8*)reginfo->strbeg);              \
1663         tmp = utf8n_to_uvchr(r, (U8*) reginfo->strend - r,                     \
1664                                                        0, UTF8_ALLOW_DEFAULT); \
1665     }                                                                          \
1666     tmp = TEST_UV(tmp);                                                        \
1667     LOAD_UTF8_CHARCLASS_ALNUM();                                               \
1668     REXEC_FBC_UTF8_SCAN( /* advances s while s < strend */                     \
1669         if (tmp == ! (TEST_UTF8((U8 *) s))) {                                  \
1670             tmp = !tmp;                                                        \
1671             IF_SUCCESS;                                                        \
1672         }                                                                      \
1673         else {                                                                 \
1674             IF_FAIL;                                                           \
1675         }                                                                      \
1676     );
1677 
1678 /* Like the above two macros.  UTF8_CODE is the complete code for handling
1679  * UTF-8.  Common to the BOUND and NBOUND cases, set-up by the FBC_BOUND, etc
1680  * macros below */
1681 #define FBC_BOUND_COMMON(UTF8_CODE, TEST_NON_UTF8, IF_SUCCESS, IF_FAIL)        \
1682     if (utf8_target) {                                                         \
1683         UTF8_CODE                                                              \
1684     }                                                                          \
1685     else {  /* Not utf8 */                                                     \
1686 	tmp = (s != reginfo->strbeg) ? UCHARAT(s - 1) : '\n';                  \
1687 	tmp = TEST_NON_UTF8(tmp);                                              \
1688 	REXEC_FBC_SCAN( /* advances s while s < strend */                      \
1689 	    if (tmp == ! TEST_NON_UTF8((U8) *s)) {                             \
1690 		IF_SUCCESS;                                                    \
1691 		tmp = !tmp;                                                    \
1692 	    }                                                                  \
1693 	    else {                                                             \
1694 		IF_FAIL;                                                       \
1695 	    }                                                                  \
1696 	);                                                                     \
1697     }                                                                          \
1698     /* Here, things have been set up by the previous code so that tmp is the   \
1699      * return of TEST_NON_UTF(s-1) or TEST_UTF8(s-1) (depending on the         \
1700      * utf8ness of the target).  We also have to check if this matches against \
1701      * the EOS, which we treat as a \n (which is the same value in both UTF-8  \
1702      * or non-UTF8, so can use the non-utf8 test condition even for a UTF-8    \
1703      * string */                                                               \
1704     if (tmp == ! TEST_NON_UTF8('\n')) {                                        \
1705         IF_SUCCESS;                                                            \
1706     }                                                                          \
1707     else {                                                                     \
1708         IF_FAIL;                                                               \
1709     }
1710 
1711 /* This is the macro to use when we want to see if something that looks like it
1712  * could match, actually does, and if so exits the loop */
1713 #define REXEC_FBC_TRYIT                            \
1714     if ((reginfo->intuit || regtry(reginfo, &s)))  \
1715         goto got_it
1716 
1717 /* The only difference between the BOUND and NBOUND cases is that
1718  * REXEC_FBC_TRYIT is called when matched in BOUND, and when non-matched in
1719  * NBOUND.  This is accomplished by passing it as either the if or else clause,
1720  * with the other one being empty (PLACEHOLDER is defined as empty).
1721  *
1722  * The TEST_FOO parameters are for operating on different forms of input, but
1723  * all should be ones that return identically for the same underlying code
1724  * points */
1725 #define FBC_BOUND(TEST_NON_UTF8, TEST_UV, TEST_UTF8)                           \
1726     FBC_BOUND_COMMON(                                                          \
1727           FBC_UTF8(TEST_UV, TEST_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER),          \
1728           TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
1729 
1730 #define FBC_BOUND_A(TEST_NON_UTF8)                                             \
1731     FBC_BOUND_COMMON(                                                          \
1732             FBC_UTF8_A(TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER),           \
1733             TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
1734 
1735 #define FBC_NBOUND(TEST_NON_UTF8, TEST_UV, TEST_UTF8)                          \
1736     FBC_BOUND_COMMON(                                                          \
1737           FBC_UTF8(TEST_UV, TEST_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT),          \
1738           TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
1739 
1740 #define FBC_NBOUND_A(TEST_NON_UTF8)                                            \
1741     FBC_BOUND_COMMON(                                                          \
1742             FBC_UTF8_A(TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT),           \
1743             TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
1744 
1745 #ifdef DEBUGGING
1746 static IV
1747 S_get_break_val_cp_checked(SV* const invlist, const UV cp_in) {
1748   IV cp_out = Perl__invlist_search(invlist, cp_in);
1749   assert(cp_out >= 0);
1750   return cp_out;
1751 }
1752 #  define _generic_GET_BREAK_VAL_CP_CHECKED(invlist, invmap, cp) \
1753 	invmap[S_get_break_val_cp_checked(invlist, cp)]
1754 #else
1755 #  define _generic_GET_BREAK_VAL_CP_CHECKED(invlist, invmap, cp) \
1756 	invmap[_invlist_search(invlist, cp)]
1757 #endif
1758 
1759 /* Takes a pointer to an inversion list, a pointer to its corresponding
1760  * inversion map, and a code point, and returns the code point's value
1761  * according to the two arrays.  It assumes that all code points have a value.
1762  * This is used as the base macro for macros for particular properties */
1763 #define _generic_GET_BREAK_VAL_CP(invlist, invmap, cp)              \
1764 	_generic_GET_BREAK_VAL_CP_CHECKED(invlist, invmap, cp)
1765 
1766 /* Same as above, but takes begin, end ptrs to a UTF-8 encoded string instead
1767  * of a code point, returning the value for the first code point in the string.
1768  * And it takes the particular macro name that finds the desired value given a
1769  * code point.  Merely convert the UTF-8 to code point and call the cp macro */
1770 #define _generic_GET_BREAK_VAL_UTF8(cp_macro, pos, strend)                     \
1771              (__ASSERT_(pos < strend)                                          \
1772                  /* Note assumes is valid UTF-8 */                             \
1773              (cp_macro(utf8_to_uvchr_buf((pos), (strend), NULL))))
1774 
1775 /* Returns the GCB value for the input code point */
1776 #define getGCB_VAL_CP(cp)                                                      \
1777           _generic_GET_BREAK_VAL_CP(                                           \
1778                                     PL_GCB_invlist,                            \
1779                                     _Perl_GCB_invmap,                          \
1780                                     (cp))
1781 
1782 /* Returns the GCB value for the first code point in the UTF-8 encoded string
1783  * bounded by pos and strend */
1784 #define getGCB_VAL_UTF8(pos, strend)                                           \
1785     _generic_GET_BREAK_VAL_UTF8(getGCB_VAL_CP, pos, strend)
1786 
1787 /* Returns the LB value for the input code point */
1788 #define getLB_VAL_CP(cp)                                                       \
1789           _generic_GET_BREAK_VAL_CP(                                           \
1790                                     PL_LB_invlist,                             \
1791                                     _Perl_LB_invmap,                           \
1792                                     (cp))
1793 
1794 /* Returns the LB value for the first code point in the UTF-8 encoded string
1795  * bounded by pos and strend */
1796 #define getLB_VAL_UTF8(pos, strend)                                            \
1797     _generic_GET_BREAK_VAL_UTF8(getLB_VAL_CP, pos, strend)
1798 
1799 
1800 /* Returns the SB value for the input code point */
1801 #define getSB_VAL_CP(cp)                                                       \
1802           _generic_GET_BREAK_VAL_CP(                                           \
1803                                     PL_SB_invlist,                             \
1804                                     _Perl_SB_invmap,                     \
1805                                     (cp))
1806 
1807 /* Returns the SB value for the first code point in the UTF-8 encoded string
1808  * bounded by pos and strend */
1809 #define getSB_VAL_UTF8(pos, strend)                                            \
1810     _generic_GET_BREAK_VAL_UTF8(getSB_VAL_CP, pos, strend)
1811 
1812 /* Returns the WB value for the input code point */
1813 #define getWB_VAL_CP(cp)                                                       \
1814           _generic_GET_BREAK_VAL_CP(                                           \
1815                                     PL_WB_invlist,                             \
1816                                     _Perl_WB_invmap,                         \
1817                                     (cp))
1818 
1819 /* Returns the WB value for the first code point in the UTF-8 encoded string
1820  * bounded by pos and strend */
1821 #define getWB_VAL_UTF8(pos, strend)                                            \
1822     _generic_GET_BREAK_VAL_UTF8(getWB_VAL_CP, pos, strend)
1823 
1824 /* We know what class REx starts with.  Try to find this position... */
1825 /* if reginfo->intuit, its a dryrun */
1826 /* annoyingly all the vars in this routine have different names from their counterparts
1827    in regmatch. /grrr */
1828 STATIC char *
1829 S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
1830     const char *strend, regmatch_info *reginfo)
1831 {
1832     dVAR;
1833     const I32 doevery = (prog->intflags & PREGf_SKIP) == 0;
1834     char *pat_string;   /* The pattern's exactish string */
1835     char *pat_end;	    /* ptr to end char of pat_string */
1836     re_fold_t folder;	/* Function for computing non-utf8 folds */
1837     const U8 *fold_array;   /* array for folding ords < 256 */
1838     STRLEN ln;
1839     STRLEN lnc;
1840     U8 c1;
1841     U8 c2;
1842     char *e;
1843     I32 tmp = 1;	/* Scratch variable? */
1844     const bool utf8_target = reginfo->is_utf8_target;
1845     UV utf8_fold_flags = 0;
1846     const bool is_utf8_pat = reginfo->is_utf8_pat;
1847     bool to_complement = FALSE; /* Invert the result?  Taking the xor of this
1848                                    with a result inverts that result, as 0^1 =
1849                                    1 and 1^1 = 0 */
1850     _char_class_number classnum;
1851 
1852     RXi_GET_DECL(prog,progi);
1853 
1854     PERL_ARGS_ASSERT_FIND_BYCLASS;
1855 
1856     /* We know what class it must start with. */
1857     switch (OP(c)) {
1858     case ANYOFL:
1859         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
1860 
1861         if (ANYOFL_UTF8_LOCALE_REQD(FLAGS(c)) && ! IN_UTF8_CTYPE_LOCALE) {
1862             Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE), utf8_locale_required);
1863         }
1864 
1865         /* FALLTHROUGH */
1866     case ANYOFD:
1867     case ANYOF:
1868         if (utf8_target) {
1869             REXEC_FBC_UTF8_CLASS_SCAN(
1870                       reginclass(prog, c, (U8*)s, (U8*) strend, utf8_target));
1871         }
1872         else {
1873             REXEC_FBC_CLASS_SCAN(REGINCLASS(prog, c, (U8*)s, 0));
1874         }
1875         break;
1876 
1877     case EXACTFA_NO_TRIE:   /* This node only generated for non-utf8 patterns */
1878         assert(! is_utf8_pat);
1879 	/* FALLTHROUGH */
1880     case EXACTFA:
1881         if (is_utf8_pat || utf8_target) {
1882             utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
1883             goto do_exactf_utf8;
1884         }
1885         fold_array = PL_fold_latin1;    /* Latin1 folds are not affected by */
1886         folder = foldEQ_latin1;	        /* /a, except the sharp s one which */
1887         goto do_exactf_non_utf8;	/* isn't dealt with by these */
1888 
1889     case EXACTF:   /* This node only generated for non-utf8 patterns */
1890         assert(! is_utf8_pat);
1891         if (utf8_target) {
1892             utf8_fold_flags = 0;
1893             goto do_exactf_utf8;
1894         }
1895         fold_array = PL_fold;
1896         folder = foldEQ;
1897         goto do_exactf_non_utf8;
1898 
1899     case EXACTFL:
1900         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
1901         if (is_utf8_pat || utf8_target || IN_UTF8_CTYPE_LOCALE) {
1902             utf8_fold_flags = FOLDEQ_LOCALE;
1903             goto do_exactf_utf8;
1904         }
1905         fold_array = PL_fold_locale;
1906         folder = foldEQ_locale;
1907         goto do_exactf_non_utf8;
1908 
1909     case EXACTFU_SS:
1910         if (is_utf8_pat) {
1911             utf8_fold_flags = FOLDEQ_S2_ALREADY_FOLDED;
1912         }
1913         goto do_exactf_utf8;
1914 
1915     case EXACTFLU8:
1916             if (! utf8_target) {    /* All code points in this node require
1917                                        UTF-8 to express.  */
1918                 break;
1919             }
1920             utf8_fold_flags =  FOLDEQ_LOCALE | FOLDEQ_S2_ALREADY_FOLDED
1921                                              | FOLDEQ_S2_FOLDS_SANE;
1922             goto do_exactf_utf8;
1923 
1924     case EXACTFU:
1925         if (is_utf8_pat || utf8_target) {
1926             utf8_fold_flags = is_utf8_pat ? FOLDEQ_S2_ALREADY_FOLDED : 0;
1927             goto do_exactf_utf8;
1928         }
1929 
1930         /* Any 'ss' in the pattern should have been replaced by regcomp,
1931          * so we don't have to worry here about this single special case
1932          * in the Latin1 range */
1933         fold_array = PL_fold_latin1;
1934         folder = foldEQ_latin1;
1935 
1936         /* FALLTHROUGH */
1937 
1938       do_exactf_non_utf8: /* Neither pattern nor string are UTF8, and there
1939                            are no glitches with fold-length differences
1940                            between the target string and pattern */
1941 
1942         /* The idea in the non-utf8 EXACTF* cases is to first find the
1943          * first character of the EXACTF* node and then, if necessary,
1944          * case-insensitively compare the full text of the node.  c1 is the
1945          * first character.  c2 is its fold.  This logic will not work for
1946          * Unicode semantics and the german sharp ss, which hence should
1947          * not be compiled into a node that gets here. */
1948         pat_string = STRING(c);
1949         ln  = STR_LEN(c);	/* length to match in octets/bytes */
1950 
1951         /* We know that we have to match at least 'ln' bytes (which is the
1952          * same as characters, since not utf8).  If we have to match 3
1953          * characters, and there are only 2 availabe, we know without
1954          * trying that it will fail; so don't start a match past the
1955          * required minimum number from the far end */
1956         e = HOP3c(strend, -((SSize_t)ln), s);
1957 
1958         if (reginfo->intuit && e < s) {
1959             e = s;			/* Due to minlen logic of intuit() */
1960         }
1961 
1962         c1 = *pat_string;
1963         c2 = fold_array[c1];
1964         if (c1 == c2) { /* If char and fold are the same */
1965             REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1);
1966         }
1967         else {
1968             REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1 || *(U8*)s == c2);
1969         }
1970         break;
1971 
1972       do_exactf_utf8:
1973       {
1974         unsigned expansion;
1975 
1976         /* If one of the operands is in utf8, we can't use the simpler folding
1977          * above, due to the fact that many different characters can have the
1978          * same fold, or portion of a fold, or different- length fold */
1979         pat_string = STRING(c);
1980         ln  = STR_LEN(c);	/* length to match in octets/bytes */
1981         pat_end = pat_string + ln;
1982         lnc = is_utf8_pat       /* length to match in characters */
1983                 ? utf8_length((U8 *) pat_string, (U8 *) pat_end)
1984                 : ln;
1985 
1986         /* We have 'lnc' characters to match in the pattern, but because of
1987          * multi-character folding, each character in the target can match
1988          * up to 3 characters (Unicode guarantees it will never exceed
1989          * this) if it is utf8-encoded; and up to 2 if not (based on the
1990          * fact that the Latin 1 folds are already determined, and the
1991          * only multi-char fold in that range is the sharp-s folding to
1992          * 'ss'.  Thus, a pattern character can match as little as 1/3 of a
1993          * string character.  Adjust lnc accordingly, rounding up, so that
1994          * if we need to match at least 4+1/3 chars, that really is 5. */
1995         expansion = (utf8_target) ? UTF8_MAX_FOLD_CHAR_EXPAND : 2;
1996         lnc = (lnc + expansion - 1) / expansion;
1997 
1998         /* As in the non-UTF8 case, if we have to match 3 characters, and
1999          * only 2 are left, it's guaranteed to fail, so don't start a
2000          * match that would require us to go beyond the end of the string
2001          */
2002         e = HOP3c(strend, -((SSize_t)lnc), s);
2003 
2004         if (reginfo->intuit && e < s) {
2005             e = s;			/* Due to minlen logic of intuit() */
2006         }
2007 
2008         /* XXX Note that we could recalculate e to stop the loop earlier,
2009          * as the worst case expansion above will rarely be met, and as we
2010          * go along we would usually find that e moves further to the left.
2011          * This would happen only after we reached the point in the loop
2012          * where if there were no expansion we should fail.  Unclear if
2013          * worth the expense */
2014 
2015         while (s <= e) {
2016             char *my_strend= (char *)strend;
2017             if (foldEQ_utf8_flags(s, &my_strend, 0,  utf8_target,
2018                   pat_string, NULL, ln, is_utf8_pat, utf8_fold_flags)
2019                 && (reginfo->intuit || regtry(reginfo, &s)) )
2020             {
2021                 goto got_it;
2022             }
2023             s += (utf8_target) ? UTF8SKIP(s) : 1;
2024         }
2025         break;
2026     }
2027 
2028     case BOUNDL:
2029         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2030         if (FLAGS(c) != TRADITIONAL_BOUND) {
2031             if (! IN_UTF8_CTYPE_LOCALE) {
2032                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2033                                                 B_ON_NON_UTF8_LOCALE_IS_WRONG);
2034             }
2035             goto do_boundu;
2036         }
2037 
2038         FBC_BOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8);
2039         break;
2040 
2041     case NBOUNDL:
2042         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2043         if (FLAGS(c) != TRADITIONAL_BOUND) {
2044             if (! IN_UTF8_CTYPE_LOCALE) {
2045                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2046                                                 B_ON_NON_UTF8_LOCALE_IS_WRONG);
2047             }
2048             goto do_nboundu;
2049         }
2050 
2051         FBC_NBOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8);
2052         break;
2053 
2054     case BOUND: /* regcomp.c makes sure that this only has the traditional \b
2055                    meaning */
2056         assert(FLAGS(c) == TRADITIONAL_BOUND);
2057 
2058         FBC_BOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8);
2059         break;
2060 
2061     case BOUNDA: /* regcomp.c makes sure that this only has the traditional \b
2062                    meaning */
2063         assert(FLAGS(c) == TRADITIONAL_BOUND);
2064 
2065         FBC_BOUND_A(isWORDCHAR_A);
2066         break;
2067 
2068     case NBOUND: /* regcomp.c makes sure that this only has the traditional \b
2069                    meaning */
2070         assert(FLAGS(c) == TRADITIONAL_BOUND);
2071 
2072         FBC_NBOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8);
2073         break;
2074 
2075     case NBOUNDA: /* regcomp.c makes sure that this only has the traditional \b
2076                    meaning */
2077         assert(FLAGS(c) == TRADITIONAL_BOUND);
2078 
2079         FBC_NBOUND_A(isWORDCHAR_A);
2080         break;
2081 
2082     case NBOUNDU:
2083         if ((bound_type) FLAGS(c) == TRADITIONAL_BOUND) {
2084             FBC_NBOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8);
2085             break;
2086         }
2087 
2088       do_nboundu:
2089 
2090         to_complement = 1;
2091         /* FALLTHROUGH */
2092 
2093     case BOUNDU:
2094       do_boundu:
2095         switch((bound_type) FLAGS(c)) {
2096             case TRADITIONAL_BOUND:
2097                 FBC_BOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8);
2098                 break;
2099             case GCB_BOUND:
2100                 if (s == reginfo->strbeg) {
2101                     if (reginfo->intuit || regtry(reginfo, &s))
2102                     {
2103                         goto got_it;
2104                     }
2105 
2106                     /* Didn't match.  Try at the next position (if there is one) */
2107                     s += (utf8_target) ? UTF8SKIP(s) : 1;
2108                     if (UNLIKELY(s >= reginfo->strend)) {
2109                         break;
2110                     }
2111                 }
2112 
2113                 if (utf8_target) {
2114                     GCB_enum before = getGCB_VAL_UTF8(
2115                                                reghop3((U8*)s, -1,
2116                                                        (U8*)(reginfo->strbeg)),
2117                                                (U8*) reginfo->strend);
2118                     while (s < strend) {
2119                         GCB_enum after = getGCB_VAL_UTF8((U8*) s,
2120                                                         (U8*) reginfo->strend);
2121                         if (   (to_complement ^ isGCB(before, after))
2122                             && (reginfo->intuit || regtry(reginfo, &s)))
2123                         {
2124                             goto got_it;
2125                         }
2126                         before = after;
2127                         s += UTF8SKIP(s);
2128                     }
2129                 }
2130                 else {  /* Not utf8.  Everything is a GCB except between CR and
2131                            LF */
2132                     while (s < strend) {
2133                         if ((to_complement ^ (   UCHARAT(s - 1) != '\r'
2134                                               || UCHARAT(s) != '\n'))
2135                             && (reginfo->intuit || regtry(reginfo, &s)))
2136                         {
2137                             goto got_it;
2138                         }
2139                         s++;
2140                     }
2141                 }
2142 
2143                 /* And, since this is a bound, it can match after the final
2144                  * character in the string */
2145                 if ((reginfo->intuit || regtry(reginfo, &s))) {
2146                     goto got_it;
2147                 }
2148                 break;
2149 
2150             case LB_BOUND:
2151                 if (s == reginfo->strbeg) {
2152                     if (reginfo->intuit || regtry(reginfo, &s)) {
2153                         goto got_it;
2154                     }
2155                     s += (utf8_target) ? UTF8SKIP(s) : 1;
2156                     if (UNLIKELY(s >= reginfo->strend)) {
2157                         break;
2158                     }
2159                 }
2160 
2161                 if (utf8_target) {
2162                     LB_enum before = getLB_VAL_UTF8(reghop3((U8*)s,
2163                                                                -1,
2164                                                                (U8*)(reginfo->strbeg)),
2165                                                        (U8*) reginfo->strend);
2166                     while (s < strend) {
2167                         LB_enum after = getLB_VAL_UTF8((U8*) s, (U8*) reginfo->strend);
2168                         if (to_complement ^ isLB(before,
2169                                                  after,
2170                                                  (U8*) reginfo->strbeg,
2171                                                  (U8*) s,
2172                                                  (U8*) reginfo->strend,
2173                                                  utf8_target)
2174                             && (reginfo->intuit || regtry(reginfo, &s)))
2175                         {
2176                             goto got_it;
2177                         }
2178                         before = after;
2179                         s += UTF8SKIP(s);
2180                     }
2181                 }
2182                 else {  /* Not utf8. */
2183                     LB_enum before = getLB_VAL_CP((U8) *(s -1));
2184                     while (s < strend) {
2185                         LB_enum after = getLB_VAL_CP((U8) *s);
2186                         if (to_complement ^ isLB(before,
2187                                                  after,
2188                                                  (U8*) reginfo->strbeg,
2189                                                  (U8*) s,
2190                                                  (U8*) reginfo->strend,
2191                                                  utf8_target)
2192                             && (reginfo->intuit || regtry(reginfo, &s)))
2193                         {
2194                             goto got_it;
2195                         }
2196                         before = after;
2197                         s++;
2198                     }
2199                 }
2200 
2201                 if (reginfo->intuit || regtry(reginfo, &s)) {
2202                     goto got_it;
2203                 }
2204 
2205                 break;
2206 
2207             case SB_BOUND:
2208                 if (s == reginfo->strbeg) {
2209                     if (reginfo->intuit || regtry(reginfo, &s)) {
2210                         goto got_it;
2211                     }
2212                     s += (utf8_target) ? UTF8SKIP(s) : 1;
2213                     if (UNLIKELY(s >= reginfo->strend)) {
2214                         break;
2215                     }
2216                 }
2217 
2218                 if (utf8_target) {
2219                     SB_enum before = getSB_VAL_UTF8(reghop3((U8*)s,
2220                                                         -1,
2221                                                         (U8*)(reginfo->strbeg)),
2222                                                       (U8*) reginfo->strend);
2223                     while (s < strend) {
2224                         SB_enum after = getSB_VAL_UTF8((U8*) s,
2225                                                          (U8*) reginfo->strend);
2226                         if ((to_complement ^ isSB(before,
2227                                                   after,
2228                                                   (U8*) reginfo->strbeg,
2229                                                   (U8*) s,
2230                                                   (U8*) reginfo->strend,
2231                                                   utf8_target))
2232                             && (reginfo->intuit || regtry(reginfo, &s)))
2233                         {
2234                             goto got_it;
2235                         }
2236                         before = after;
2237                         s += UTF8SKIP(s);
2238                     }
2239                 }
2240                 else {  /* Not utf8. */
2241                     SB_enum before = getSB_VAL_CP((U8) *(s -1));
2242                     while (s < strend) {
2243                         SB_enum after = getSB_VAL_CP((U8) *s);
2244                         if ((to_complement ^ isSB(before,
2245                                                   after,
2246                                                   (U8*) reginfo->strbeg,
2247                                                   (U8*) s,
2248                                                   (U8*) reginfo->strend,
2249                                                   utf8_target))
2250                             && (reginfo->intuit || regtry(reginfo, &s)))
2251                         {
2252                             goto got_it;
2253                         }
2254                         before = after;
2255                         s++;
2256                     }
2257                 }
2258 
2259                 /* Here are at the final position in the target string.  The SB
2260                  * value is always true here, so matches, depending on other
2261                  * constraints */
2262                 if (reginfo->intuit || regtry(reginfo, &s)) {
2263                     goto got_it;
2264                 }
2265 
2266                 break;
2267 
2268             case WB_BOUND:
2269                 if (s == reginfo->strbeg) {
2270                     if (reginfo->intuit || regtry(reginfo, &s)) {
2271                         goto got_it;
2272                     }
2273                     s += (utf8_target) ? UTF8SKIP(s) : 1;
2274                     if (UNLIKELY(s >= reginfo->strend)) {
2275                         break;
2276                     }
2277                 }
2278 
2279                 if (utf8_target) {
2280                     /* We are at a boundary between char_sub_0 and char_sub_1.
2281                      * We also keep track of the value for char_sub_-1 as we
2282                      * loop through the line.   Context may be needed to make a
2283                      * determination, and if so, this can save having to
2284                      * recalculate it */
2285                     WB_enum previous = WB_UNKNOWN;
2286                     WB_enum before = getWB_VAL_UTF8(
2287                                               reghop3((U8*)s,
2288                                                       -1,
2289                                                       (U8*)(reginfo->strbeg)),
2290                                               (U8*) reginfo->strend);
2291                     while (s < strend) {
2292                         WB_enum after = getWB_VAL_UTF8((U8*) s,
2293                                                         (U8*) reginfo->strend);
2294                         if ((to_complement ^ isWB(previous,
2295                                                   before,
2296                                                   after,
2297                                                   (U8*) reginfo->strbeg,
2298                                                   (U8*) s,
2299                                                   (U8*) reginfo->strend,
2300                                                   utf8_target))
2301                             && (reginfo->intuit || regtry(reginfo, &s)))
2302                         {
2303                             goto got_it;
2304                         }
2305                         previous = before;
2306                         before = after;
2307                         s += UTF8SKIP(s);
2308                     }
2309                 }
2310                 else {  /* Not utf8. */
2311                     WB_enum previous = WB_UNKNOWN;
2312                     WB_enum before = getWB_VAL_CP((U8) *(s -1));
2313                     while (s < strend) {
2314                         WB_enum after = getWB_VAL_CP((U8) *s);
2315                         if ((to_complement ^ isWB(previous,
2316                                                   before,
2317                                                   after,
2318                                                   (U8*) reginfo->strbeg,
2319                                                   (U8*) s,
2320                                                   (U8*) reginfo->strend,
2321                                                   utf8_target))
2322                             && (reginfo->intuit || regtry(reginfo, &s)))
2323                         {
2324                             goto got_it;
2325                         }
2326                         previous = before;
2327                         before = after;
2328                         s++;
2329                     }
2330                 }
2331 
2332                 if (reginfo->intuit || regtry(reginfo, &s)) {
2333                     goto got_it;
2334                 }
2335         }
2336         break;
2337 
2338     case LNBREAK:
2339         REXEC_FBC_CSCAN(is_LNBREAK_utf8_safe(s, strend),
2340                         is_LNBREAK_latin1_safe(s, strend)
2341         );
2342         break;
2343 
2344     /* The argument to all the POSIX node types is the class number to pass to
2345      * _generic_isCC() to build a mask for searching in PL_charclass[] */
2346 
2347     case NPOSIXL:
2348         to_complement = 1;
2349         /* FALLTHROUGH */
2350 
2351     case POSIXL:
2352         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2353         REXEC_FBC_CSCAN(to_complement ^ cBOOL(isFOO_utf8_lc(FLAGS(c), (U8 *) s)),
2354                         to_complement ^ cBOOL(isFOO_lc(FLAGS(c), *s)));
2355         break;
2356 
2357     case NPOSIXD:
2358         to_complement = 1;
2359         /* FALLTHROUGH */
2360 
2361     case POSIXD:
2362         if (utf8_target) {
2363             goto posix_utf8;
2364         }
2365         goto posixa;
2366 
2367     case NPOSIXA:
2368         if (utf8_target) {
2369             /* The complement of something that matches only ASCII matches all
2370              * non-ASCII, plus everything in ASCII that isn't in the class. */
2371             REXEC_FBC_UTF8_CLASS_SCAN(! isASCII_utf8(s)
2372                                       || ! _generic_isCC_A(*s, FLAGS(c)));
2373             break;
2374         }
2375 
2376         to_complement = 1;
2377         /* FALLTHROUGH */
2378 
2379     case POSIXA:
2380       posixa:
2381         /* Don't need to worry about utf8, as it can match only a single
2382          * byte invariant character. */
2383         REXEC_FBC_CLASS_SCAN(
2384                         to_complement ^ cBOOL(_generic_isCC_A(*s, FLAGS(c))));
2385         break;
2386 
2387     case NPOSIXU:
2388         to_complement = 1;
2389         /* FALLTHROUGH */
2390 
2391     case POSIXU:
2392         if (! utf8_target) {
2393             REXEC_FBC_CLASS_SCAN(to_complement ^ cBOOL(_generic_isCC(*s,
2394                                                                     FLAGS(c))));
2395         }
2396         else {
2397 
2398           posix_utf8:
2399             classnum = (_char_class_number) FLAGS(c);
2400             if (classnum < _FIRST_NON_SWASH_CC) {
2401                 while (s < strend) {
2402 
2403                     /* We avoid loading in the swash as long as possible, but
2404                      * should we have to, we jump to a separate loop.  This
2405                      * extra 'if' statement is what keeps this code from being
2406                      * just a call to REXEC_FBC_UTF8_CLASS_SCAN() */
2407                     if (UTF8_IS_ABOVE_LATIN1(*s)) {
2408                         goto found_above_latin1;
2409                     }
2410                     if ((UTF8_IS_INVARIANT(*s)
2411                          && to_complement ^ cBOOL(_generic_isCC((U8) *s,
2412                                                                 classnum)))
2413                         || (UTF8_IS_DOWNGRADEABLE_START(*s)
2414                             && to_complement ^ cBOOL(
2415                                 _generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(*s,
2416                                                                       *(s + 1)),
2417                                               classnum))))
2418                     {
2419                         if (tmp && (reginfo->intuit || regtry(reginfo, &s)))
2420                             goto got_it;
2421                         else {
2422                             tmp = doevery;
2423                         }
2424                     }
2425                     else {
2426                         tmp = 1;
2427                     }
2428                     s += UTF8SKIP(s);
2429                 }
2430             }
2431             else switch (classnum) {    /* These classes are implemented as
2432                                            macros */
2433                 case _CC_ENUM_SPACE:
2434                     REXEC_FBC_UTF8_CLASS_SCAN(
2435                                         to_complement ^ cBOOL(isSPACE_utf8(s)));
2436                     break;
2437 
2438                 case _CC_ENUM_BLANK:
2439                     REXEC_FBC_UTF8_CLASS_SCAN(
2440                                         to_complement ^ cBOOL(isBLANK_utf8(s)));
2441                     break;
2442 
2443                 case _CC_ENUM_XDIGIT:
2444                     REXEC_FBC_UTF8_CLASS_SCAN(
2445                                        to_complement ^ cBOOL(isXDIGIT_utf8(s)));
2446                     break;
2447 
2448                 case _CC_ENUM_VERTSPACE:
2449                     REXEC_FBC_UTF8_CLASS_SCAN(
2450                                        to_complement ^ cBOOL(isVERTWS_utf8(s)));
2451                     break;
2452 
2453                 case _CC_ENUM_CNTRL:
2454                     REXEC_FBC_UTF8_CLASS_SCAN(
2455                                         to_complement ^ cBOOL(isCNTRL_utf8(s)));
2456                     break;
2457 
2458                 default:
2459                     Perl_croak(aTHX_ "panic: find_byclass() node %d='%s' has an unexpected character class '%d'", OP(c), PL_reg_name[OP(c)], classnum);
2460                     NOT_REACHED; /* NOTREACHED */
2461             }
2462         }
2463         break;
2464 
2465       found_above_latin1:   /* Here we have to load a swash to get the result
2466                                for the current code point */
2467         if (! PL_utf8_swash_ptrs[classnum]) {
2468             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
2469             PL_utf8_swash_ptrs[classnum] =
2470                     _core_swash_init("utf8",
2471                                      "",
2472                                      &PL_sv_undef, 1, 0,
2473                                      PL_XPosix_ptrs[classnum], &flags);
2474         }
2475 
2476         /* This is a copy of the loop above for swash classes, though using the
2477          * FBC macro instead of being expanded out.  Since we've loaded the
2478          * swash, we don't have to check for that each time through the loop */
2479         REXEC_FBC_UTF8_CLASS_SCAN(
2480                 to_complement ^ cBOOL(_generic_utf8(
2481                                       classnum,
2482                                       s,
2483                                       swash_fetch(PL_utf8_swash_ptrs[classnum],
2484                                                   (U8 *) s, TRUE))));
2485         break;
2486 
2487     case AHOCORASICKC:
2488     case AHOCORASICK:
2489         {
2490             DECL_TRIE_TYPE(c);
2491             /* what trie are we using right now */
2492             reg_ac_data *aho = (reg_ac_data*)progi->data->data[ ARG( c ) ];
2493             reg_trie_data *trie = (reg_trie_data*)progi->data->data[ aho->trie ];
2494             HV *widecharmap = MUTABLE_HV(progi->data->data[ aho->trie + 1 ]);
2495 
2496             const char *last_start = strend - trie->minlen;
2497 #ifdef DEBUGGING
2498             const char *real_start = s;
2499 #endif
2500             STRLEN maxlen = trie->maxlen;
2501             SV *sv_points;
2502             U8 **points; /* map of where we were in the input string
2503                             when reading a given char. For ASCII this
2504                             is unnecessary overhead as the relationship
2505                             is always 1:1, but for Unicode, especially
2506                             case folded Unicode this is not true. */
2507             U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
2508             U8 *bitmap=NULL;
2509 
2510 
2511             GET_RE_DEBUG_FLAGS_DECL;
2512 
2513             /* We can't just allocate points here. We need to wrap it in
2514              * an SV so it gets freed properly if there is a croak while
2515              * running the match */
2516             ENTER;
2517             SAVETMPS;
2518             sv_points=newSV(maxlen * sizeof(U8 *));
2519             SvCUR_set(sv_points,
2520                 maxlen * sizeof(U8 *));
2521             SvPOK_on(sv_points);
2522             sv_2mortal(sv_points);
2523             points=(U8**)SvPV_nolen(sv_points );
2524             if ( trie_type != trie_utf8_fold
2525                  && (trie->bitmap || OP(c)==AHOCORASICKC) )
2526             {
2527                 if (trie->bitmap)
2528                     bitmap=(U8*)trie->bitmap;
2529                 else
2530                     bitmap=(U8*)ANYOF_BITMAP(c);
2531             }
2532             /* this is the Aho-Corasick algorithm modified a touch
2533                to include special handling for long "unknown char" sequences.
2534                The basic idea being that we use AC as long as we are dealing
2535                with a possible matching char, when we encounter an unknown char
2536                (and we have not encountered an accepting state) we scan forward
2537                until we find a legal starting char.
2538                AC matching is basically that of trie matching, except that when
2539                we encounter a failing transition, we fall back to the current
2540                states "fail state", and try the current char again, a process
2541                we repeat until we reach the root state, state 1, or a legal
2542                transition. If we fail on the root state then we can either
2543                terminate if we have reached an accepting state previously, or
2544                restart the entire process from the beginning if we have not.
2545 
2546              */
2547             while (s <= last_start) {
2548                 const U32 uniflags = UTF8_ALLOW_DEFAULT;
2549                 U8 *uc = (U8*)s;
2550                 U16 charid = 0;
2551                 U32 base = 1;
2552                 U32 state = 1;
2553                 UV uvc = 0;
2554                 STRLEN len = 0;
2555                 STRLEN foldlen = 0;
2556                 U8 *uscan = (U8*)NULL;
2557                 U8 *leftmost = NULL;
2558 #ifdef DEBUGGING
2559                 U32 accepted_word= 0;
2560 #endif
2561                 U32 pointpos = 0;
2562 
2563                 while ( state && uc <= (U8*)strend ) {
2564                     int failed=0;
2565                     U32 word = aho->states[ state ].wordnum;
2566 
2567                     if( state==1 ) {
2568                         if ( bitmap ) {
2569                             DEBUG_TRIE_EXECUTE_r(
2570                                 if ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
2571                                     dump_exec_pos( (char *)uc, c, strend, real_start,
2572                                         (char *)uc, utf8_target, 0 );
2573                                     Perl_re_printf( aTHX_
2574                                         " Scanning for legal start char...\n");
2575                                 }
2576                             );
2577                             if (utf8_target) {
2578                                 while ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
2579                                     uc += UTF8SKIP(uc);
2580                                 }
2581                             } else {
2582                                 while ( uc <= (U8*)last_start  && !BITMAP_TEST(bitmap,*uc) ) {
2583                                     uc++;
2584                                 }
2585                             }
2586                             s= (char *)uc;
2587                         }
2588                         if (uc >(U8*)last_start) break;
2589                     }
2590 
2591                     if ( word ) {
2592                         U8 *lpos= points[ (pointpos - trie->wordinfo[word].len) % maxlen ];
2593                         if (!leftmost || lpos < leftmost) {
2594                             DEBUG_r(accepted_word=word);
2595                             leftmost= lpos;
2596                         }
2597                         if (base==0) break;
2598 
2599                     }
2600                     points[pointpos++ % maxlen]= uc;
2601                     if (foldlen || uc < (U8*)strend) {
2602                         REXEC_TRIE_READ_CHAR(trie_type, trie,
2603                                          widecharmap, uc,
2604                                          uscan, len, uvc, charid, foldlen,
2605                                          foldbuf, uniflags);
2606                         DEBUG_TRIE_EXECUTE_r({
2607                             dump_exec_pos( (char *)uc, c, strend,
2608                                         real_start, s, utf8_target, 0);
2609                             Perl_re_printf( aTHX_
2610                                 " Charid:%3u CP:%4"UVxf" ",
2611                                  charid, uvc);
2612                         });
2613                     }
2614                     else {
2615                         len = 0;
2616                         charid = 0;
2617                     }
2618 
2619 
2620                     do {
2621 #ifdef DEBUGGING
2622                         word = aho->states[ state ].wordnum;
2623 #endif
2624                         base = aho->states[ state ].trans.base;
2625 
2626                         DEBUG_TRIE_EXECUTE_r({
2627                             if (failed)
2628                                 dump_exec_pos( (char *)uc, c, strend, real_start,
2629                                     s,   utf8_target, 0 );
2630                             Perl_re_printf( aTHX_
2631                                 "%sState: %4"UVxf", word=%"UVxf,
2632                                 failed ? " Fail transition to " : "",
2633                                 (UV)state, (UV)word);
2634                         });
2635                         if ( base ) {
2636                             U32 tmp;
2637                             I32 offset;
2638                             if (charid &&
2639                                  ( ((offset = base + charid
2640                                     - 1 - trie->uniquecharcount)) >= 0)
2641                                  && ((U32)offset < trie->lasttrans)
2642                                  && trie->trans[offset].check == state
2643                                  && (tmp=trie->trans[offset].next))
2644                             {
2645                                 DEBUG_TRIE_EXECUTE_r(
2646                                     Perl_re_printf( aTHX_ " - legal\n"));
2647                                 state = tmp;
2648                                 break;
2649                             }
2650                             else {
2651                                 DEBUG_TRIE_EXECUTE_r(
2652                                     Perl_re_printf( aTHX_ " - fail\n"));
2653                                 failed = 1;
2654                                 state = aho->fail[state];
2655                             }
2656                         }
2657                         else {
2658                             /* we must be accepting here */
2659                             DEBUG_TRIE_EXECUTE_r(
2660                                     Perl_re_printf( aTHX_ " - accepting\n"));
2661                             failed = 1;
2662                             break;
2663                         }
2664                     } while(state);
2665                     uc += len;
2666                     if (failed) {
2667                         if (leftmost)
2668                             break;
2669                         if (!state) state = 1;
2670                     }
2671                 }
2672                 if ( aho->states[ state ].wordnum ) {
2673                     U8 *lpos = points[ (pointpos - trie->wordinfo[aho->states[ state ].wordnum].len) % maxlen ];
2674                     if (!leftmost || lpos < leftmost) {
2675                         DEBUG_r(accepted_word=aho->states[ state ].wordnum);
2676                         leftmost = lpos;
2677                     }
2678                 }
2679                 if (leftmost) {
2680                     s = (char*)leftmost;
2681                     DEBUG_TRIE_EXECUTE_r({
2682                         Perl_re_printf( aTHX_  "Matches word #%"UVxf" at position %"IVdf". Trying full pattern...\n",
2683                             (UV)accepted_word, (IV)(s - real_start)
2684                         );
2685                     });
2686                     if (reginfo->intuit || regtry(reginfo, &s)) {
2687                         FREETMPS;
2688                         LEAVE;
2689                         goto got_it;
2690                     }
2691                     s = HOPc(s,1);
2692                     DEBUG_TRIE_EXECUTE_r({
2693                         Perl_re_printf( aTHX_ "Pattern failed. Looking for new start point...\n");
2694                     });
2695                 } else {
2696                     DEBUG_TRIE_EXECUTE_r(
2697                         Perl_re_printf( aTHX_ "No match.\n"));
2698                     break;
2699                 }
2700             }
2701             FREETMPS;
2702             LEAVE;
2703         }
2704         break;
2705     default:
2706         Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
2707     }
2708     return 0;
2709   got_it:
2710     return s;
2711 }
2712 
2713 /* set RX_SAVED_COPY, RX_SUBBEG etc.
2714  * flags have same meanings as with regexec_flags() */
2715 
2716 static void
2717 S_reg_set_capture_string(pTHX_ REGEXP * const rx,
2718                             char *strbeg,
2719                             char *strend,
2720                             SV *sv,
2721                             U32 flags,
2722                             bool utf8_target)
2723 {
2724     struct regexp *const prog = ReANY(rx);
2725 
2726     if (flags & REXEC_COPY_STR) {
2727 #ifdef PERL_ANY_COW
2728         if (SvCANCOW(sv)) {
2729             DEBUG_C(Perl_re_printf( aTHX_
2730                               "Copy on write: regexp capture, type %d\n",
2731                                     (int) SvTYPE(sv)));
2732             /* Create a new COW SV to share the match string and store
2733              * in saved_copy, unless the current COW SV in saved_copy
2734              * is valid and suitable for our purpose */
2735             if ((   prog->saved_copy
2736                  && SvIsCOW(prog->saved_copy)
2737                  && SvPOKp(prog->saved_copy)
2738                  && SvIsCOW(sv)
2739                  && SvPOKp(sv)
2740                  && SvPVX(sv) == SvPVX(prog->saved_copy)))
2741             {
2742                 /* just reuse saved_copy SV */
2743                 if (RXp_MATCH_COPIED(prog)) {
2744                     Safefree(prog->subbeg);
2745                     RXp_MATCH_COPIED_off(prog);
2746                 }
2747             }
2748             else {
2749                 /* create new COW SV to share string */
2750                 RX_MATCH_COPY_FREE(rx);
2751                 prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
2752             }
2753             prog->subbeg = (char *)SvPVX_const(prog->saved_copy);
2754             assert (SvPOKp(prog->saved_copy));
2755             prog->sublen  = strend - strbeg;
2756             prog->suboffset = 0;
2757             prog->subcoffset = 0;
2758         } else
2759 #endif
2760         {
2761             SSize_t min = 0;
2762             SSize_t max = strend - strbeg;
2763             SSize_t sublen;
2764 
2765             if (    (flags & REXEC_COPY_SKIP_POST)
2766                 && !(prog->extflags & RXf_PMf_KEEPCOPY) /* //p */
2767                 && !(PL_sawampersand & SAWAMPERSAND_RIGHT)
2768             ) { /* don't copy $' part of string */
2769                 U32 n = 0;
2770                 max = -1;
2771                 /* calculate the right-most part of the string covered
2772                  * by a capture. Due to lookahead, this may be to
2773                  * the right of $&, so we have to scan all captures */
2774                 while (n <= prog->lastparen) {
2775                     if (prog->offs[n].end > max)
2776                         max = prog->offs[n].end;
2777                     n++;
2778                 }
2779                 if (max == -1)
2780                     max = (PL_sawampersand & SAWAMPERSAND_LEFT)
2781                             ? prog->offs[0].start
2782                             : 0;
2783                 assert(max >= 0 && max <= strend - strbeg);
2784             }
2785 
2786             if (    (flags & REXEC_COPY_SKIP_PRE)
2787                 && !(prog->extflags & RXf_PMf_KEEPCOPY) /* //p */
2788                 && !(PL_sawampersand & SAWAMPERSAND_LEFT)
2789             ) { /* don't copy $` part of string */
2790                 U32 n = 0;
2791                 min = max;
2792                 /* calculate the left-most part of the string covered
2793                  * by a capture. Due to lookbehind, this may be to
2794                  * the left of $&, so we have to scan all captures */
2795                 while (min && n <= prog->lastparen) {
2796                     if (   prog->offs[n].start != -1
2797                         && prog->offs[n].start < min)
2798                     {
2799                         min = prog->offs[n].start;
2800                     }
2801                     n++;
2802                 }
2803                 if ((PL_sawampersand & SAWAMPERSAND_RIGHT)
2804                     && min >  prog->offs[0].end
2805                 )
2806                     min = prog->offs[0].end;
2807 
2808             }
2809 
2810             assert(min >= 0 && min <= max && min <= strend - strbeg);
2811             sublen = max - min;
2812 
2813             if (RX_MATCH_COPIED(rx)) {
2814                 if (sublen > prog->sublen)
2815                     prog->subbeg =
2816                             (char*)saferealloc(prog->subbeg, sublen+1);
2817             }
2818             else
2819                 prog->subbeg = (char*)safemalloc(sublen+1);
2820             Copy(strbeg + min, prog->subbeg, sublen, char);
2821             prog->subbeg[sublen] = '\0';
2822             prog->suboffset = min;
2823             prog->sublen = sublen;
2824             RX_MATCH_COPIED_on(rx);
2825         }
2826         prog->subcoffset = prog->suboffset;
2827         if (prog->suboffset && utf8_target) {
2828             /* Convert byte offset to chars.
2829              * XXX ideally should only compute this if @-/@+
2830              * has been seen, a la PL_sawampersand ??? */
2831 
2832             /* If there's a direct correspondence between the
2833              * string which we're matching and the original SV,
2834              * then we can use the utf8 len cache associated with
2835              * the SV. In particular, it means that under //g,
2836              * sv_pos_b2u() will use the previously cached
2837              * position to speed up working out the new length of
2838              * subcoffset, rather than counting from the start of
2839              * the string each time. This stops
2840              *   $x = "\x{100}" x 1E6; 1 while $x =~ /(.)/g;
2841              * from going quadratic */
2842             if (SvPOKp(sv) && SvPVX(sv) == strbeg)
2843                 prog->subcoffset = sv_pos_b2u_flags(sv, prog->subcoffset,
2844                                                 SV_GMAGIC|SV_CONST_RETURN);
2845             else
2846                 prog->subcoffset = utf8_length((U8*)strbeg,
2847                                     (U8*)(strbeg+prog->suboffset));
2848         }
2849     }
2850     else {
2851         RX_MATCH_COPY_FREE(rx);
2852         prog->subbeg = strbeg;
2853         prog->suboffset = 0;
2854         prog->subcoffset = 0;
2855         prog->sublen = strend - strbeg;
2856     }
2857 }
2858 
2859 
2860 
2861 
2862 /*
2863  - regexec_flags - match a regexp against a string
2864  */
2865 I32
2866 Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
2867 	      char *strbeg, SSize_t minend, SV *sv, void *data, U32 flags)
2868 /* stringarg: the point in the string at which to begin matching */
2869 /* strend:    pointer to null at end of string */
2870 /* strbeg:    real beginning of string */
2871 /* minend:    end of match must be >= minend bytes after stringarg. */
2872 /* sv:        SV being matched: only used for utf8 flag, pos() etc; string
2873  *            itself is accessed via the pointers above */
2874 /* data:      May be used for some additional optimizations.
2875               Currently unused. */
2876 /* flags:     For optimizations. See REXEC_* in regexp.h */
2877 
2878 {
2879     struct regexp *const prog = ReANY(rx);
2880     char *s;
2881     regnode *c;
2882     char *startpos;
2883     SSize_t minlen;		/* must match at least this many chars */
2884     SSize_t dontbother = 0;	/* how many characters not to try at end */
2885     const bool utf8_target = cBOOL(DO_UTF8(sv));
2886     I32 multiline;
2887     RXi_GET_DECL(prog,progi);
2888     regmatch_info reginfo_buf;  /* create some info to pass to regtry etc */
2889     regmatch_info *const reginfo = &reginfo_buf;
2890     regexp_paren_pair *swap = NULL;
2891     I32 oldsave;
2892     GET_RE_DEBUG_FLAGS_DECL;
2893 
2894     PERL_ARGS_ASSERT_REGEXEC_FLAGS;
2895     PERL_UNUSED_ARG(data);
2896 
2897     /* Be paranoid... */
2898     if (prog == NULL) {
2899 	Perl_croak(aTHX_ "NULL regexp parameter");
2900     }
2901 
2902     DEBUG_EXECUTE_r(
2903         debug_start_match(rx, utf8_target, stringarg, strend,
2904         "Matching");
2905     );
2906 
2907     startpos = stringarg;
2908 
2909     /* set these early as they may be used by the HOP macros below */
2910     reginfo->strbeg = strbeg;
2911     reginfo->strend = strend;
2912     reginfo->is_utf8_target = cBOOL(utf8_target);
2913 
2914     if (prog->intflags & PREGf_GPOS_SEEN) {
2915         MAGIC *mg;
2916 
2917         /* set reginfo->ganch, the position where \G can match */
2918 
2919         reginfo->ganch =
2920             (flags & REXEC_IGNOREPOS)
2921             ? stringarg /* use start pos rather than pos() */
2922             : ((mg = mg_find_mglob(sv)) && mg->mg_len >= 0)
2923               /* Defined pos(): */
2924             ? strbeg + MgBYTEPOS(mg, sv, strbeg, strend-strbeg)
2925             : strbeg; /* pos() not defined; use start of string */
2926 
2927         DEBUG_GPOS_r(Perl_re_printf( aTHX_
2928             "GPOS ganch set to strbeg[%"IVdf"]\n", (IV)(reginfo->ganch - strbeg)));
2929 
2930         /* in the presence of \G, we may need to start looking earlier in
2931          * the string than the suggested start point of stringarg:
2932          * if prog->gofs is set, then that's a known, fixed minimum
2933          * offset, such as
2934          * /..\G/:   gofs = 2
2935          * /ab|c\G/: gofs = 1
2936          * or if the minimum offset isn't known, then we have to go back
2937          * to the start of the string, e.g. /w+\G/
2938          */
2939 
2940         if (prog->intflags & PREGf_ANCH_GPOS) {
2941             if (prog->gofs) {
2942                 startpos = HOPBACKc(reginfo->ganch, prog->gofs);
2943                 if (!startpos ||
2944                     ((flags & REXEC_FAIL_ON_UNDERFLOW) && startpos < stringarg))
2945                 {
2946                     DEBUG_r(Perl_re_printf( aTHX_
2947                             "fail: ganch-gofs before earliest possible start\n"));
2948                     return 0;
2949                 }
2950             }
2951             else
2952                 startpos = reginfo->ganch;
2953         }
2954         else if (prog->gofs) {
2955             startpos = HOPBACKc(startpos, prog->gofs);
2956             if (!startpos)
2957                 startpos = strbeg;
2958         }
2959         else if (prog->intflags & PREGf_GPOS_FLOAT)
2960             startpos = strbeg;
2961     }
2962 
2963     minlen = prog->minlen;
2964     if ((startpos + minlen) > strend || startpos < strbeg) {
2965         DEBUG_r(Perl_re_printf( aTHX_
2966                     "Regex match can't succeed, so not even tried\n"));
2967         return 0;
2968     }
2969 
2970     /* at the end of this function, we'll do a LEAVE_SCOPE(oldsave),
2971      * which will call destuctors to reset PL_regmatch_state, free higher
2972      * PL_regmatch_slabs, and clean up regmatch_info_aux and
2973      * regmatch_info_aux_eval */
2974 
2975     oldsave = PL_savestack_ix;
2976 
2977     s = startpos;
2978 
2979     if ((prog->extflags & RXf_USE_INTUIT)
2980         && !(flags & REXEC_CHECKED))
2981     {
2982 	s = re_intuit_start(rx, sv, strbeg, startpos, strend,
2983                                     flags, NULL);
2984 	if (!s)
2985 	    return 0;
2986 
2987 	if (prog->extflags & RXf_CHECK_ALL) {
2988             /* we can match based purely on the result of INTUIT.
2989              * Set up captures etc just for $& and $-[0]
2990              * (an intuit-only match wont have $1,$2,..) */
2991             assert(!prog->nparens);
2992 
2993             /* s/// doesn't like it if $& is earlier than where we asked it to
2994              * start searching (which can happen on something like /.\G/) */
2995             if (       (flags & REXEC_FAIL_ON_UNDERFLOW)
2996                     && (s < stringarg))
2997             {
2998                 /* this should only be possible under \G */
2999                 assert(prog->intflags & PREGf_GPOS_SEEN);
3000                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
3001                     "matched, but failing for REXEC_FAIL_ON_UNDERFLOW\n"));
3002                 goto phooey;
3003             }
3004 
3005             /* match via INTUIT shouldn't have any captures.
3006              * Let @-, @+, $^N know */
3007             prog->lastparen = prog->lastcloseparen = 0;
3008             RX_MATCH_UTF8_set(rx, utf8_target);
3009             prog->offs[0].start = s - strbeg;
3010             prog->offs[0].end = utf8_target
3011                 ? (char*)utf8_hop((U8*)s, prog->minlenret) - strbeg
3012                 : s - strbeg + prog->minlenret;
3013             if ( !(flags & REXEC_NOT_FIRST) )
3014                 S_reg_set_capture_string(aTHX_ rx,
3015                                         strbeg, strend,
3016                                         sv, flags, utf8_target);
3017 
3018 	    return 1;
3019         }
3020     }
3021 
3022     multiline = prog->extflags & RXf_PMf_MULTILINE;
3023 
3024     if (strend - s < (minlen+(prog->check_offset_min<0?prog->check_offset_min:0))) {
3025         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
3026 			      "String too short [regexec_flags]...\n"));
3027 	goto phooey;
3028     }
3029 
3030     /* Check validity of program. */
3031     if (UCHARAT(progi->program) != REG_MAGIC) {
3032 	Perl_croak(aTHX_ "corrupted regexp program");
3033     }
3034 
3035     RX_MATCH_TAINTED_off(rx);
3036     RX_MATCH_UTF8_set(rx, utf8_target);
3037 
3038     reginfo->prog = rx;	 /* Yes, sorry that this is confusing.  */
3039     reginfo->intuit = 0;
3040     reginfo->is_utf8_pat = cBOOL(RX_UTF8(rx));
3041     reginfo->warned = FALSE;
3042     reginfo->sv = sv;
3043     reginfo->poscache_maxiter = 0; /* not yet started a countdown */
3044     /* see how far we have to get to not match where we matched before */
3045     reginfo->till = stringarg + minend;
3046 
3047     if (prog->extflags & RXf_EVAL_SEEN && SvPADTMP(sv)) {
3048         /* SAVEFREESV, not sv_mortalcopy, as this SV must last until after
3049            S_cleanup_regmatch_info_aux has executed (registered by
3050            SAVEDESTRUCTOR_X below).  S_cleanup_regmatch_info_aux modifies
3051            magic belonging to this SV.
3052            Not newSVsv, either, as it does not COW.
3053         */
3054         reginfo->sv = newSV(0);
3055         SvSetSV_nosteal(reginfo->sv, sv);
3056         SAVEFREESV(reginfo->sv);
3057     }
3058 
3059     /* reserve next 2 or 3 slots in PL_regmatch_state:
3060      * slot N+0: may currently be in use: skip it
3061      * slot N+1: use for regmatch_info_aux struct
3062      * slot N+2: use for regmatch_info_aux_eval struct if we have (?{})'s
3063      * slot N+3: ready for use by regmatch()
3064      */
3065 
3066     {
3067         regmatch_state *old_regmatch_state;
3068         regmatch_slab  *old_regmatch_slab;
3069         int i, max = (prog->extflags & RXf_EVAL_SEEN) ? 2 : 1;
3070 
3071         /* on first ever match, allocate first slab */
3072         if (!PL_regmatch_slab) {
3073             Newx(PL_regmatch_slab, 1, regmatch_slab);
3074             PL_regmatch_slab->prev = NULL;
3075             PL_regmatch_slab->next = NULL;
3076             PL_regmatch_state = SLAB_FIRST(PL_regmatch_slab);
3077         }
3078 
3079         old_regmatch_state = PL_regmatch_state;
3080         old_regmatch_slab  = PL_regmatch_slab;
3081 
3082         for (i=0; i <= max; i++) {
3083             if (i == 1)
3084                 reginfo->info_aux = &(PL_regmatch_state->u.info_aux);
3085             else if (i ==2)
3086                 reginfo->info_aux_eval =
3087                 reginfo->info_aux->info_aux_eval =
3088                             &(PL_regmatch_state->u.info_aux_eval);
3089 
3090             if (++PL_regmatch_state >  SLAB_LAST(PL_regmatch_slab))
3091                 PL_regmatch_state = S_push_slab(aTHX);
3092         }
3093 
3094         /* note initial PL_regmatch_state position; at end of match we'll
3095          * pop back to there and free any higher slabs */
3096 
3097         reginfo->info_aux->old_regmatch_state = old_regmatch_state;
3098         reginfo->info_aux->old_regmatch_slab  = old_regmatch_slab;
3099         reginfo->info_aux->poscache = NULL;
3100 
3101         SAVEDESTRUCTOR_X(S_cleanup_regmatch_info_aux, reginfo->info_aux);
3102 
3103         if ((prog->extflags & RXf_EVAL_SEEN))
3104             S_setup_eval_state(aTHX_ reginfo);
3105         else
3106             reginfo->info_aux_eval = reginfo->info_aux->info_aux_eval = NULL;
3107     }
3108 
3109     /* If there is a "must appear" string, look for it. */
3110 
3111     if (PL_curpm && (PM_GETRE(PL_curpm) == rx)) {
3112         /* We have to be careful. If the previous successful match
3113            was from this regex we don't want a subsequent partially
3114            successful match to clobber the old results.
3115            So when we detect this possibility we add a swap buffer
3116            to the re, and switch the buffer each match. If we fail,
3117            we switch it back; otherwise we leave it swapped.
3118         */
3119         swap = prog->offs;
3120         /* do we need a save destructor here for eval dies? */
3121         Newxz(prog->offs, (prog->nparens + 1), regexp_paren_pair);
3122         DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
3123 	    "rex=0x%"UVxf" saving  offs: orig=0x%"UVxf" new=0x%"UVxf"\n",
3124 	    PTR2UV(prog),
3125 	    PTR2UV(swap),
3126 	    PTR2UV(prog->offs)
3127 	));
3128     }
3129 
3130     if (prog->recurse_locinput)
3131         Zero(prog->recurse_locinput,prog->nparens + 1, char *);
3132 
3133     /* Simplest case: anchored match need be tried only once, or with
3134      * MBOL, only at the beginning of each line.
3135      *
3136      * Note that /.*.../ sets PREGf_IMPLICIT|MBOL, while /.*.../s sets
3137      * PREGf_IMPLICIT|SBOL. The idea is that with /.*.../s, if it doesn't
3138      * match at the start of the string then it won't match anywhere else
3139      * either; while with /.*.../, if it doesn't match at the beginning,
3140      * the earliest it could match is at the start of the next line */
3141 
3142     if (prog->intflags & (PREGf_ANCH & ~PREGf_ANCH_GPOS)) {
3143         char *end;
3144 
3145 	if (regtry(reginfo, &s))
3146 	    goto got_it;
3147 
3148         if (!(prog->intflags & PREGf_ANCH_MBOL))
3149             goto phooey;
3150 
3151         /* didn't match at start, try at other newline positions */
3152 
3153         if (minlen)
3154             dontbother = minlen - 1;
3155         end = HOP3c(strend, -dontbother, strbeg) - 1;
3156 
3157         /* skip to next newline */
3158 
3159         while (s <= end) { /* note it could be possible to match at the end of the string */
3160             /* NB: newlines are the same in unicode as they are in latin */
3161             if (*s++ != '\n')
3162                 continue;
3163             if (prog->check_substr || prog->check_utf8) {
3164             /* note that with PREGf_IMPLICIT, intuit can only fail
3165              * or return the start position, so it's of limited utility.
3166              * Nevertheless, I made the decision that the potential for
3167              * quick fail was still worth it - DAPM */
3168                 s = re_intuit_start(rx, sv, strbeg, s, strend, flags, NULL);
3169                 if (!s)
3170                     goto phooey;
3171             }
3172             if (regtry(reginfo, &s))
3173                 goto got_it;
3174         }
3175         goto phooey;
3176     } /* end anchored search */
3177 
3178     if (prog->intflags & PREGf_ANCH_GPOS)
3179     {
3180         /* PREGf_ANCH_GPOS should never be true if PREGf_GPOS_SEEN is not true */
3181         assert(prog->intflags & PREGf_GPOS_SEEN);
3182         /* For anchored \G, the only position it can match from is
3183          * (ganch-gofs); we already set startpos to this above; if intuit
3184          * moved us on from there, we can't possibly succeed */
3185         assert(startpos == HOPBACKc(reginfo->ganch, prog->gofs));
3186 	if (s == startpos && regtry(reginfo, &s))
3187 	    goto got_it;
3188 	goto phooey;
3189     }
3190 
3191     /* Messy cases:  unanchored match. */
3192     if ((prog->anchored_substr || prog->anchored_utf8) && prog->intflags & PREGf_SKIP) {
3193 	/* we have /x+whatever/ */
3194 	/* it must be a one character string (XXXX Except is_utf8_pat?) */
3195 	char ch;
3196 #ifdef DEBUGGING
3197 	int did_match = 0;
3198 #endif
3199 	if (utf8_target) {
3200             if (! prog->anchored_utf8) {
3201                 to_utf8_substr(prog);
3202             }
3203             ch = SvPVX_const(prog->anchored_utf8)[0];
3204 	    REXEC_FBC_SCAN(
3205 		if (*s == ch) {
3206 		    DEBUG_EXECUTE_r( did_match = 1 );
3207 		    if (regtry(reginfo, &s)) goto got_it;
3208 		    s += UTF8SKIP(s);
3209 		    while (s < strend && *s == ch)
3210 			s += UTF8SKIP(s);
3211 		}
3212 	    );
3213 
3214 	}
3215 	else {
3216             if (! prog->anchored_substr) {
3217                 if (! to_byte_substr(prog)) {
3218                     NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
3219                 }
3220             }
3221             ch = SvPVX_const(prog->anchored_substr)[0];
3222 	    REXEC_FBC_SCAN(
3223 		if (*s == ch) {
3224 		    DEBUG_EXECUTE_r( did_match = 1 );
3225 		    if (regtry(reginfo, &s)) goto got_it;
3226 		    s++;
3227 		    while (s < strend && *s == ch)
3228 			s++;
3229 		}
3230 	    );
3231 	}
3232 	DEBUG_EXECUTE_r(if (!did_match)
3233                 Perl_re_printf( aTHX_
3234                                   "Did not find anchored character...\n")
3235                );
3236     }
3237     else if (prog->anchored_substr != NULL
3238 	      || prog->anchored_utf8 != NULL
3239 	      || ((prog->float_substr != NULL || prog->float_utf8 != NULL)
3240 		  && prog->float_max_offset < strend - s)) {
3241 	SV *must;
3242 	SSize_t back_max;
3243 	SSize_t back_min;
3244 	char *last;
3245 	char *last1;		/* Last position checked before */
3246 #ifdef DEBUGGING
3247 	int did_match = 0;
3248 #endif
3249 	if (prog->anchored_substr || prog->anchored_utf8) {
3250 	    if (utf8_target) {
3251                 if (! prog->anchored_utf8) {
3252                     to_utf8_substr(prog);
3253                 }
3254                 must = prog->anchored_utf8;
3255             }
3256             else {
3257                 if (! prog->anchored_substr) {
3258                     if (! to_byte_substr(prog)) {
3259                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
3260                     }
3261                 }
3262                 must = prog->anchored_substr;
3263             }
3264 	    back_max = back_min = prog->anchored_offset;
3265 	} else {
3266 	    if (utf8_target) {
3267                 if (! prog->float_utf8) {
3268                     to_utf8_substr(prog);
3269                 }
3270                 must = prog->float_utf8;
3271             }
3272             else {
3273                 if (! prog->float_substr) {
3274                     if (! to_byte_substr(prog)) {
3275                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
3276                     }
3277                 }
3278                 must = prog->float_substr;
3279             }
3280 	    back_max = prog->float_max_offset;
3281 	    back_min = prog->float_min_offset;
3282 	}
3283 
3284         if (back_min<0) {
3285 	    last = strend;
3286 	} else {
3287             last = HOP3c(strend,	/* Cannot start after this */
3288         	  -(SSize_t)(CHR_SVLEN(must)
3289         		 - (SvTAIL(must) != 0) + back_min), strbeg);
3290         }
3291 	if (s > reginfo->strbeg)
3292 	    last1 = HOPc(s, -1);
3293 	else
3294 	    last1 = s - 1;	/* bogus */
3295 
3296 	/* XXXX check_substr already used to find "s", can optimize if
3297 	   check_substr==must. */
3298 	dontbother = 0;
3299 	strend = HOPc(strend, -dontbother);
3300 	while ( (s <= last) &&
3301 		(s = fbm_instr((unsigned char*)HOP4c(s, back_min, strbeg,  strend),
3302 				  (unsigned char*)strend, must,
3303 				  multiline ? FBMrf_MULTILINE : 0)) ) {
3304 	    DEBUG_EXECUTE_r( did_match = 1 );
3305 	    if (HOPc(s, -back_max) > last1) {
3306 		last1 = HOPc(s, -back_min);
3307 		s = HOPc(s, -back_max);
3308 	    }
3309 	    else {
3310 		char * const t = (last1 >= reginfo->strbeg)
3311                                     ? HOPc(last1, 1) : last1 + 1;
3312 
3313 		last1 = HOPc(s, -back_min);
3314 		s = t;
3315 	    }
3316 	    if (utf8_target) {
3317 		while (s <= last1) {
3318 		    if (regtry(reginfo, &s))
3319 			goto got_it;
3320                     if (s >= last1) {
3321                         s++; /* to break out of outer loop */
3322                         break;
3323                     }
3324                     s += UTF8SKIP(s);
3325 		}
3326 	    }
3327 	    else {
3328 		while (s <= last1) {
3329 		    if (regtry(reginfo, &s))
3330 			goto got_it;
3331 		    s++;
3332 		}
3333 	    }
3334 	}
3335 	DEBUG_EXECUTE_r(if (!did_match) {
3336             RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
3337                 SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
3338             Perl_re_printf( aTHX_  "Did not find %s substr %s%s...\n",
3339 			      ((must == prog->anchored_substr || must == prog->anchored_utf8)
3340 			       ? "anchored" : "floating"),
3341                 quoted, RE_SV_TAIL(must));
3342         });
3343 	goto phooey;
3344     }
3345     else if ( (c = progi->regstclass) ) {
3346 	if (minlen) {
3347 	    const OPCODE op = OP(progi->regstclass);
3348 	    /* don't bother with what can't match */
3349 	    if (PL_regkind[op] != EXACT && PL_regkind[op] != TRIE)
3350 	        strend = HOPc(strend, -(minlen - 1));
3351 	}
3352 	DEBUG_EXECUTE_r({
3353 	    SV * const prop = sv_newmortal();
3354             regprop(prog, prop, c, reginfo, NULL);
3355 	    {
3356 		RE_PV_QUOTED_DECL(quoted,utf8_target,PERL_DEBUG_PAD_ZERO(1),
3357 		    s,strend-s,60);
3358                 Perl_re_printf( aTHX_
3359 		    "Matching stclass %.*s against %s (%d bytes)\n",
3360 		    (int)SvCUR(prop), SvPVX_const(prop),
3361 		     quoted, (int)(strend - s));
3362 	    }
3363 	});
3364         if (find_byclass(prog, c, s, strend, reginfo))
3365 	    goto got_it;
3366         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "Contradicts stclass... [regexec_flags]\n"));
3367     }
3368     else {
3369 	dontbother = 0;
3370 	if (prog->float_substr != NULL || prog->float_utf8 != NULL) {
3371 	    /* Trim the end. */
3372 	    char *last= NULL;
3373 	    SV* float_real;
3374 	    STRLEN len;
3375 	    const char *little;
3376 
3377 	    if (utf8_target) {
3378                 if (! prog->float_utf8) {
3379                     to_utf8_substr(prog);
3380                 }
3381                 float_real = prog->float_utf8;
3382             }
3383             else {
3384                 if (! prog->float_substr) {
3385                     if (! to_byte_substr(prog)) {
3386                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
3387                     }
3388                 }
3389                 float_real = prog->float_substr;
3390             }
3391 
3392             little = SvPV_const(float_real, len);
3393 	    if (SvTAIL(float_real)) {
3394                     /* This means that float_real contains an artificial \n on
3395                      * the end due to the presence of something like this:
3396                      * /foo$/ where we can match both "foo" and "foo\n" at the
3397                      * end of the string.  So we have to compare the end of the
3398                      * string first against the float_real without the \n and
3399                      * then against the full float_real with the string.  We
3400                      * have to watch out for cases where the string might be
3401                      * smaller than the float_real or the float_real without
3402                      * the \n. */
3403 		    char *checkpos= strend - len;
3404 		    DEBUG_OPTIMISE_r(
3405                         Perl_re_printf( aTHX_
3406 			    "%sChecking for float_real.%s\n",
3407 			    PL_colors[4], PL_colors[5]));
3408 		    if (checkpos + 1 < strbeg) {
3409                         /* can't match, even if we remove the trailing \n
3410                          * string is too short to match */
3411 			DEBUG_EXECUTE_r(
3412                             Perl_re_printf( aTHX_
3413 				"%sString shorter than required trailing substring, cannot match.%s\n",
3414 				PL_colors[4], PL_colors[5]));
3415 			goto phooey;
3416 		    } else if (memEQ(checkpos + 1, little, len - 1)) {
3417                         /* can match, the end of the string matches without the
3418                          * "\n" */
3419 			last = checkpos + 1;
3420 		    } else if (checkpos < strbeg) {
3421                         /* cant match, string is too short when the "\n" is
3422                          * included */
3423 			DEBUG_EXECUTE_r(
3424                             Perl_re_printf( aTHX_
3425 				"%sString does not contain required trailing substring, cannot match.%s\n",
3426 				PL_colors[4], PL_colors[5]));
3427 			goto phooey;
3428 		    } else if (!multiline) {
3429                         /* non multiline match, so compare with the "\n" at the
3430                          * end of the string */
3431 			if (memEQ(checkpos, little, len)) {
3432 			    last= checkpos;
3433 			} else {
3434 			    DEBUG_EXECUTE_r(
3435                                 Perl_re_printf( aTHX_
3436 				    "%sString does not contain required trailing substring, cannot match.%s\n",
3437 				    PL_colors[4], PL_colors[5]));
3438 			    goto phooey;
3439 			}
3440 		    } else {
3441                         /* multiline match, so we have to search for a place
3442                          * where the full string is located */
3443 			goto find_last;
3444 		    }
3445 	    } else {
3446 		  find_last:
3447 		    if (len)
3448 			last = rninstr(s, strend, little, little + len);
3449 		    else
3450 			last = strend;	/* matching "$" */
3451 	    }
3452 	    if (!last) {
3453                 /* at one point this block contained a comment which was
3454                  * probably incorrect, which said that this was a "should not
3455                  * happen" case.  Even if it was true when it was written I am
3456                  * pretty sure it is not anymore, so I have removed the comment
3457                  * and replaced it with this one. Yves */
3458 		DEBUG_EXECUTE_r(
3459                     Perl_re_printf( aTHX_
3460 			"%sString does not contain required substring, cannot match.%s\n",
3461                         PL_colors[4], PL_colors[5]
3462 	            ));
3463 		goto phooey;
3464 	    }
3465 	    dontbother = strend - last + prog->float_min_offset;
3466 	}
3467 	if (minlen && (dontbother < minlen))
3468 	    dontbother = minlen - 1;
3469 	strend -= dontbother; 		   /* this one's always in bytes! */
3470 	/* We don't know much -- general case. */
3471 	if (utf8_target) {
3472 	    for (;;) {
3473 		if (regtry(reginfo, &s))
3474 		    goto got_it;
3475 		if (s >= strend)
3476 		    break;
3477 		s += UTF8SKIP(s);
3478 	    };
3479 	}
3480 	else {
3481 	    do {
3482 		if (regtry(reginfo, &s))
3483 		    goto got_it;
3484 	    } while (s++ < strend);
3485 	}
3486     }
3487 
3488     /* Failure. */
3489     goto phooey;
3490 
3491   got_it:
3492     /* s/// doesn't like it if $& is earlier than where we asked it to
3493      * start searching (which can happen on something like /.\G/) */
3494     if (       (flags & REXEC_FAIL_ON_UNDERFLOW)
3495             && (prog->offs[0].start < stringarg - strbeg))
3496     {
3497         /* this should only be possible under \G */
3498         assert(prog->intflags & PREGf_GPOS_SEEN);
3499         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
3500             "matched, but failing for REXEC_FAIL_ON_UNDERFLOW\n"));
3501         goto phooey;
3502     }
3503 
3504     DEBUG_BUFFERS_r(
3505 	if (swap)
3506             Perl_re_printf( aTHX_
3507 		"rex=0x%"UVxf" freeing offs: 0x%"UVxf"\n",
3508 		PTR2UV(prog),
3509 		PTR2UV(swap)
3510 	    );
3511     );
3512     Safefree(swap);
3513 
3514     /* clean up; this will trigger destructors that will free all slabs
3515      * above the current one, and cleanup the regmatch_info_aux
3516      * and regmatch_info_aux_eval sructs */
3517 
3518     LEAVE_SCOPE(oldsave);
3519 
3520     if (RXp_PAREN_NAMES(prog))
3521         (void)hv_iterinit(RXp_PAREN_NAMES(prog));
3522 
3523     /* make sure $`, $&, $', and $digit will work later */
3524     if ( !(flags & REXEC_NOT_FIRST) )
3525         S_reg_set_capture_string(aTHX_ rx,
3526                                     strbeg, reginfo->strend,
3527                                     sv, flags, utf8_target);
3528 
3529     return 1;
3530 
3531   phooey:
3532     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "%sMatch failed%s\n",
3533 			  PL_colors[4], PL_colors[5]));
3534 
3535     /* clean up; this will trigger destructors that will free all slabs
3536      * above the current one, and cleanup the regmatch_info_aux
3537      * and regmatch_info_aux_eval sructs */
3538 
3539     LEAVE_SCOPE(oldsave);
3540 
3541     if (swap) {
3542         /* we failed :-( roll it back */
3543         DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
3544 	    "rex=0x%"UVxf" rolling back offs: freeing=0x%"UVxf" restoring=0x%"UVxf"\n",
3545 	    PTR2UV(prog),
3546 	    PTR2UV(prog->offs),
3547 	    PTR2UV(swap)
3548 	));
3549         Safefree(prog->offs);
3550         prog->offs = swap;
3551     }
3552     return 0;
3553 }
3554 
3555 
3556 /* Set which rex is pointed to by PL_reg_curpm, handling ref counting.
3557  * Do inc before dec, in case old and new rex are the same */
3558 #define SET_reg_curpm(Re2)                          \
3559     if (reginfo->info_aux_eval) {                   \
3560 	(void)ReREFCNT_inc(Re2);		    \
3561 	ReREFCNT_dec(PM_GETRE(PL_reg_curpm));	    \
3562 	PM_SETRE((PL_reg_curpm), (Re2));	    \
3563     }
3564 
3565 
3566 /*
3567  - regtry - try match at specific point
3568  */
3569 STATIC bool			/* 0 failure, 1 success */
3570 S_regtry(pTHX_ regmatch_info *reginfo, char **startposp)
3571 {
3572     CHECKPOINT lastcp;
3573     REGEXP *const rx = reginfo->prog;
3574     regexp *const prog = ReANY(rx);
3575     SSize_t result;
3576 #ifdef DEBUGGING
3577     U32 depth = 0; /* used by REGCP_SET */
3578 #endif
3579     RXi_GET_DECL(prog,progi);
3580     GET_RE_DEBUG_FLAGS_DECL;
3581 
3582     PERL_ARGS_ASSERT_REGTRY;
3583 
3584     reginfo->cutpoint=NULL;
3585 
3586     prog->offs[0].start = *startposp - reginfo->strbeg;
3587     prog->lastparen = 0;
3588     prog->lastcloseparen = 0;
3589 
3590     /* XXXX What this code is doing here?!!!  There should be no need
3591        to do this again and again, prog->lastparen should take care of
3592        this!  --ilya*/
3593 
3594     /* Tests pat.t#187 and split.t#{13,14} seem to depend on this code.
3595      * Actually, the code in regcppop() (which Ilya may be meaning by
3596      * prog->lastparen), is not needed at all by the test suite
3597      * (op/regexp, op/pat, op/split), but that code is needed otherwise
3598      * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
3599      * Meanwhile, this code *is* needed for the
3600      * above-mentioned test suite tests to succeed.  The common theme
3601      * on those tests seems to be returning null fields from matches.
3602      * --jhi updated by dapm */
3603 #if 1
3604     if (prog->nparens) {
3605 	regexp_paren_pair *pp = prog->offs;
3606 	I32 i;
3607 	for (i = prog->nparens; i > (I32)prog->lastparen; i--) {
3608 	    ++pp;
3609 	    pp->start = -1;
3610 	    pp->end = -1;
3611 	}
3612     }
3613 #endif
3614     REGCP_SET(lastcp);
3615     result = regmatch(reginfo, *startposp, progi->program + 1);
3616     if (result != -1) {
3617 	prog->offs[0].end = result;
3618 	return 1;
3619     }
3620     if (reginfo->cutpoint)
3621         *startposp= reginfo->cutpoint;
3622     REGCP_UNWIND(lastcp);
3623     return 0;
3624 }
3625 
3626 
3627 #define sayYES goto yes
3628 #define sayNO goto no
3629 #define sayNO_SILENT goto no_silent
3630 
3631 /* we dont use STMT_START/END here because it leads to
3632    "unreachable code" warnings, which are bogus, but distracting. */
3633 #define CACHEsayNO \
3634     if (ST.cache_mask) \
3635        reginfo->info_aux->poscache[ST.cache_offset] |= ST.cache_mask; \
3636     sayNO
3637 
3638 /* this is used to determine how far from the left messages like
3639    'failed...' are printed in regexec.c. It should be set such that
3640    messages are inline with the regop output that created them.
3641 */
3642 #define REPORT_CODE_OFF 29
3643 #define INDENT_CHARS(depth) ((int)(depth) % 20)
3644 #ifdef DEBUGGING
3645 int
3646 Perl_re_exec_indentf(pTHX_ const char *fmt, U32 depth, ...)
3647 {
3648     va_list ap;
3649     int result;
3650     PerlIO *f= Perl_debug_log;
3651     PERL_ARGS_ASSERT_RE_EXEC_INDENTF;
3652     va_start(ap, depth);
3653     PerlIO_printf(f, "%*s|%4"UVuf"| %*s", REPORT_CODE_OFF, "", (UV)depth, INDENT_CHARS(depth), "" );
3654     result = PerlIO_vprintf(f, fmt, ap);
3655     va_end(ap);
3656     return result;
3657 }
3658 #endif /* DEBUGGING */
3659 
3660 
3661 #define CHRTEST_UNINIT -1001 /* c1/c2 haven't been calculated yet */
3662 #define CHRTEST_VOID   -1000 /* the c1/c2 "next char" test should be skipped */
3663 #define CHRTEST_NOT_A_CP_1 -999
3664 #define CHRTEST_NOT_A_CP_2 -998
3665 
3666 /* grab a new slab and return the first slot in it */
3667 
3668 STATIC regmatch_state *
3669 S_push_slab(pTHX)
3670 {
3671 #if PERL_VERSION < 9 && !defined(PERL_CORE)
3672     dMY_CXT;
3673 #endif
3674     regmatch_slab *s = PL_regmatch_slab->next;
3675     if (!s) {
3676 	Newx(s, 1, regmatch_slab);
3677 	s->prev = PL_regmatch_slab;
3678 	s->next = NULL;
3679 	PL_regmatch_slab->next = s;
3680     }
3681     PL_regmatch_slab = s;
3682     return SLAB_FIRST(s);
3683 }
3684 
3685 
3686 /* push a new state then goto it */
3687 
3688 #define PUSH_STATE_GOTO(state, node, input) \
3689     pushinput = input; \
3690     scan = node; \
3691     st->resume_state = state; \
3692     goto push_state;
3693 
3694 /* push a new state with success backtracking, then goto it */
3695 
3696 #define PUSH_YES_STATE_GOTO(state, node, input) \
3697     pushinput = input; \
3698     scan = node; \
3699     st->resume_state = state; \
3700     goto push_yes_state;
3701 
3702 
3703 
3704 
3705 /*
3706 
3707 regmatch() - main matching routine
3708 
3709 This is basically one big switch statement in a loop. We execute an op,
3710 set 'next' to point the next op, and continue. If we come to a point which
3711 we may need to backtrack to on failure such as (A|B|C), we push a
3712 backtrack state onto the backtrack stack. On failure, we pop the top
3713 state, and re-enter the loop at the state indicated. If there are no more
3714 states to pop, we return failure.
3715 
3716 Sometimes we also need to backtrack on success; for example /A+/, where
3717 after successfully matching one A, we need to go back and try to
3718 match another one; similarly for lookahead assertions: if the assertion
3719 completes successfully, we backtrack to the state just before the assertion
3720 and then carry on.  In these cases, the pushed state is marked as
3721 'backtrack on success too'. This marking is in fact done by a chain of
3722 pointers, each pointing to the previous 'yes' state. On success, we pop to
3723 the nearest yes state, discarding any intermediate failure-only states.
3724 Sometimes a yes state is pushed just to force some cleanup code to be
3725 called at the end of a successful match or submatch; e.g. (??{$re}) uses
3726 it to free the inner regex.
3727 
3728 Note that failure backtracking rewinds the cursor position, while
3729 success backtracking leaves it alone.
3730 
3731 A pattern is complete when the END op is executed, while a subpattern
3732 such as (?=foo) is complete when the SUCCESS op is executed. Both of these
3733 ops trigger the "pop to last yes state if any, otherwise return true"
3734 behaviour.
3735 
3736 A common convention in this function is to use A and B to refer to the two
3737 subpatterns (or to the first nodes thereof) in patterns like /A*B/: so A is
3738 the subpattern to be matched possibly multiple times, while B is the entire
3739 rest of the pattern. Variable and state names reflect this convention.
3740 
3741 The states in the main switch are the union of ops and failure/success of
3742 substates associated with with that op.  For example, IFMATCH is the op
3743 that does lookahead assertions /(?=A)B/ and so the IFMATCH state means
3744 'execute IFMATCH'; while IFMATCH_A is a state saying that we have just
3745 successfully matched A and IFMATCH_A_fail is a state saying that we have
3746 just failed to match A. Resume states always come in pairs. The backtrack
3747 state we push is marked as 'IFMATCH_A', but when that is popped, we resume
3748 at IFMATCH_A or IFMATCH_A_fail, depending on whether we are backtracking
3749 on success or failure.
3750 
3751 The struct that holds a backtracking state is actually a big union, with
3752 one variant for each major type of op. The variable st points to the
3753 top-most backtrack struct. To make the code clearer, within each
3754 block of code we #define ST to alias the relevant union.
3755 
3756 Here's a concrete example of a (vastly oversimplified) IFMATCH
3757 implementation:
3758 
3759     switch (state) {
3760     ....
3761 
3762 #define ST st->u.ifmatch
3763 
3764     case IFMATCH: // we are executing the IFMATCH op, (?=A)B
3765 	ST.foo = ...; // some state we wish to save
3766 	...
3767 	// push a yes backtrack state with a resume value of
3768 	// IFMATCH_A/IFMATCH_A_fail, then continue execution at the
3769 	// first node of A:
3770 	PUSH_YES_STATE_GOTO(IFMATCH_A, A, newinput);
3771 	// NOTREACHED
3772 
3773     case IFMATCH_A: // we have successfully executed A; now continue with B
3774 	next = B;
3775 	bar = ST.foo; // do something with the preserved value
3776 	break;
3777 
3778     case IFMATCH_A_fail: // A failed, so the assertion failed
3779 	...;   // do some housekeeping, then ...
3780 	sayNO; // propagate the failure
3781 
3782 #undef ST
3783 
3784     ...
3785     }
3786 
3787 For any old-timers reading this who are familiar with the old recursive
3788 approach, the code above is equivalent to:
3789 
3790     case IFMATCH: // we are executing the IFMATCH op, (?=A)B
3791     {
3792 	int foo = ...
3793 	...
3794 	if (regmatch(A)) {
3795 	    next = B;
3796 	    bar = foo;
3797 	    break;
3798 	}
3799 	...;   // do some housekeeping, then ...
3800 	sayNO; // propagate the failure
3801     }
3802 
3803 The topmost backtrack state, pointed to by st, is usually free. If you
3804 want to claim it, populate any ST.foo fields in it with values you wish to
3805 save, then do one of
3806 
3807 	PUSH_STATE_GOTO(resume_state, node, newinput);
3808 	PUSH_YES_STATE_GOTO(resume_state, node, newinput);
3809 
3810 which sets that backtrack state's resume value to 'resume_state', pushes a
3811 new free entry to the top of the backtrack stack, then goes to 'node'.
3812 On backtracking, the free slot is popped, and the saved state becomes the
3813 new free state. An ST.foo field in this new top state can be temporarily
3814 accessed to retrieve values, but once the main loop is re-entered, it
3815 becomes available for reuse.
3816 
3817 Note that the depth of the backtrack stack constantly increases during the
3818 left-to-right execution of the pattern, rather than going up and down with
3819 the pattern nesting. For example the stack is at its maximum at Z at the
3820 end of the pattern, rather than at X in the following:
3821 
3822     /(((X)+)+)+....(Y)+....Z/
3823 
3824 The only exceptions to this are lookahead/behind assertions and the cut,
3825 (?>A), which pop all the backtrack states associated with A before
3826 continuing.
3827 
3828 Backtrack state structs are allocated in slabs of about 4K in size.
3829 PL_regmatch_state and st always point to the currently active state,
3830 and PL_regmatch_slab points to the slab currently containing
3831 PL_regmatch_state.  The first time regmatch() is called, the first slab is
3832 allocated, and is never freed until interpreter destruction. When the slab
3833 is full, a new one is allocated and chained to the end. At exit from
3834 regmatch(), slabs allocated since entry are freed.
3835 
3836 */
3837 
3838 
3839 #define DEBUG_STATE_pp(pp)                                  \
3840     DEBUG_STATE_r({                                         \
3841         DUMP_EXEC_POS(locinput, scan, utf8_target,depth);   \
3842         Perl_re_printf( aTHX_                                           \
3843             "%*s" pp " %s%s%s%s%s\n",                       \
3844             INDENT_CHARS(depth), "",                        \
3845             PL_reg_name[st->resume_state],                  \
3846             ((st==yes_state||st==mark_state) ? "[" : ""),   \
3847             ((st==yes_state) ? "Y" : ""),                   \
3848             ((st==mark_state) ? "M" : ""),                  \
3849             ((st==yes_state||st==mark_state) ? "]" : "")    \
3850         );                                                  \
3851     });
3852 
3853 
3854 #define REG_NODE_NUM(x) ((x) ? (int)((x)-prog) : -1)
3855 
3856 #ifdef DEBUGGING
3857 
3858 STATIC void
3859 S_debug_start_match(pTHX_ const REGEXP *prog, const bool utf8_target,
3860     const char *start, const char *end, const char *blurb)
3861 {
3862     const bool utf8_pat = RX_UTF8(prog) ? 1 : 0;
3863 
3864     PERL_ARGS_ASSERT_DEBUG_START_MATCH;
3865 
3866     if (!PL_colorset)
3867             reginitcolors();
3868     {
3869         RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0),
3870             RX_PRECOMP_const(prog), RX_PRELEN(prog), 60);
3871 
3872         RE_PV_QUOTED_DECL(s1, utf8_target, PERL_DEBUG_PAD_ZERO(1),
3873             start, end - start, 60);
3874 
3875         Perl_re_printf( aTHX_
3876             "%s%s REx%s %s against %s\n",
3877 		       PL_colors[4], blurb, PL_colors[5], s0, s1);
3878 
3879         if (utf8_target||utf8_pat)
3880             Perl_re_printf( aTHX_  "UTF-8 %s%s%s...\n",
3881                 utf8_pat ? "pattern" : "",
3882                 utf8_pat && utf8_target ? " and " : "",
3883                 utf8_target ? "string" : ""
3884             );
3885     }
3886 }
3887 
3888 STATIC void
3889 S_dump_exec_pos(pTHX_ const char *locinput,
3890                       const regnode *scan,
3891                       const char *loc_regeol,
3892                       const char *loc_bostr,
3893                       const char *loc_reg_starttry,
3894                       const bool utf8_target,
3895                       const U32 depth
3896                 )
3897 {
3898     const int docolor = *PL_colors[0] || *PL_colors[2] || *PL_colors[4];
3899     const int taill = (docolor ? 10 : 7); /* 3 chars for "> <" */
3900     int l = (loc_regeol - locinput) > taill ? taill : (loc_regeol - locinput);
3901     /* The part of the string before starttry has one color
3902        (pref0_len chars), between starttry and current
3903        position another one (pref_len - pref0_len chars),
3904        after the current position the third one.
3905        We assume that pref0_len <= pref_len, otherwise we
3906        decrease pref0_len.  */
3907     int pref_len = (locinput - loc_bostr) > (5 + taill) - l
3908 	? (5 + taill) - l : locinput - loc_bostr;
3909     int pref0_len;
3910 
3911     PERL_ARGS_ASSERT_DUMP_EXEC_POS;
3912 
3913     while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput - pref_len)))
3914 	pref_len++;
3915     pref0_len = pref_len  - (locinput - loc_reg_starttry);
3916     if (l + pref_len < (5 + taill) && l < loc_regeol - locinput)
3917 	l = ( loc_regeol - locinput > (5 + taill) - pref_len
3918 	      ? (5 + taill) - pref_len : loc_regeol - locinput);
3919     while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput + l)))
3920 	l--;
3921     if (pref0_len < 0)
3922 	pref0_len = 0;
3923     if (pref0_len > pref_len)
3924 	pref0_len = pref_len;
3925     {
3926 	const int is_uni = utf8_target ? 1 : 0;
3927 
3928 	RE_PV_COLOR_DECL(s0,len0,is_uni,PERL_DEBUG_PAD(0),
3929 	    (locinput - pref_len),pref0_len, 60, 4, 5);
3930 
3931 	RE_PV_COLOR_DECL(s1,len1,is_uni,PERL_DEBUG_PAD(1),
3932 		    (locinput - pref_len + pref0_len),
3933 		    pref_len - pref0_len, 60, 2, 3);
3934 
3935 	RE_PV_COLOR_DECL(s2,len2,is_uni,PERL_DEBUG_PAD(2),
3936 		    locinput, loc_regeol - locinput, 10, 0, 1);
3937 
3938 	const STRLEN tlen=len0+len1+len2;
3939         Perl_re_printf( aTHX_
3940                     "%4"IVdf" <%.*s%.*s%s%.*s>%*s|%4u| ",
3941 		    (IV)(locinput - loc_bostr),
3942 		    len0, s0,
3943 		    len1, s1,
3944 		    (docolor ? "" : "> <"),
3945 		    len2, s2,
3946 		    (int)(tlen > 19 ? 0 :  19 - tlen),
3947                     "",
3948                     depth);
3949     }
3950 }
3951 
3952 #endif
3953 
3954 /* reg_check_named_buff_matched()
3955  * Checks to see if a named buffer has matched. The data array of
3956  * buffer numbers corresponding to the buffer is expected to reside
3957  * in the regexp->data->data array in the slot stored in the ARG() of
3958  * node involved. Note that this routine doesn't actually care about the
3959  * name, that information is not preserved from compilation to execution.
3960  * Returns the index of the leftmost defined buffer with the given name
3961  * or 0 if non of the buffers matched.
3962  */
3963 STATIC I32
3964 S_reg_check_named_buff_matched(const regexp *rex, const regnode *scan)
3965 {
3966     I32 n;
3967     RXi_GET_DECL(rex,rexi);
3968     SV *sv_dat= MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
3969     I32 *nums=(I32*)SvPVX(sv_dat);
3970 
3971     PERL_ARGS_ASSERT_REG_CHECK_NAMED_BUFF_MATCHED;
3972 
3973     for ( n=0; n<SvIVX(sv_dat); n++ ) {
3974         if ((I32)rex->lastparen >= nums[n] &&
3975             rex->offs[nums[n]].end != -1)
3976         {
3977             return nums[n];
3978         }
3979     }
3980     return 0;
3981 }
3982 
3983 
3984 static bool
3985 S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p,
3986         U8* c1_utf8, int *c2p, U8* c2_utf8, regmatch_info *reginfo)
3987 {
3988     /* This function determines if there are one or two characters that match
3989      * the first character of the passed-in EXACTish node <text_node>, and if
3990      * so, returns them in the passed-in pointers.
3991      *
3992      * If it determines that no possible character in the target string can
3993      * match, it returns FALSE; otherwise TRUE.  (The FALSE situation occurs if
3994      * the first character in <text_node> requires UTF-8 to represent, and the
3995      * target string isn't in UTF-8.)
3996      *
3997      * If there are more than two characters that could match the beginning of
3998      * <text_node>, or if more context is required to determine a match or not,
3999      * it sets both *<c1p> and *<c2p> to CHRTEST_VOID.
4000      *
4001      * The motiviation behind this function is to allow the caller to set up
4002      * tight loops for matching.  If <text_node> is of type EXACT, there is
4003      * only one possible character that can match its first character, and so
4004      * the situation is quite simple.  But things get much more complicated if
4005      * folding is involved.  It may be that the first character of an EXACTFish
4006      * node doesn't participate in any possible fold, e.g., punctuation, so it
4007      * can be matched only by itself.  The vast majority of characters that are
4008      * in folds match just two things, their lower and upper-case equivalents.
4009      * But not all are like that; some have multiple possible matches, or match
4010      * sequences of more than one character.  This function sorts all that out.
4011      *
4012      * Consider the patterns A*B or A*?B where A and B are arbitrary.  In a
4013      * loop of trying to match A*, we know we can't exit where the thing
4014      * following it isn't a B.  And something can't be a B unless it is the
4015      * beginning of B.  By putting a quick test for that beginning in a tight
4016      * loop, we can rule out things that can't possibly be B without having to
4017      * break out of the loop, thus avoiding work.  Similarly, if A is a single
4018      * character, we can make a tight loop matching A*, using the outputs of
4019      * this function.
4020      *
4021      * If the target string to match isn't in UTF-8, and there aren't
4022      * complications which require CHRTEST_VOID, *<c1p> and *<c2p> are set to
4023      * the one or two possible octets (which are characters in this situation)
4024      * that can match.  In all cases, if there is only one character that can
4025      * match, *<c1p> and *<c2p> will be identical.
4026      *
4027      * If the target string is in UTF-8, the buffers pointed to by <c1_utf8>
4028      * and <c2_utf8> will contain the one or two UTF-8 sequences of bytes that
4029      * can match the beginning of <text_node>.  They should be declared with at
4030      * least length UTF8_MAXBYTES+1.  (If the target string isn't in UTF-8, it is
4031      * undefined what these contain.)  If one or both of the buffers are
4032      * invariant under UTF-8, *<c1p>, and *<c2p> will also be set to the
4033      * corresponding invariant.  If variant, the corresponding *<c1p> and/or
4034      * *<c2p> will be set to a negative number(s) that shouldn't match any code
4035      * point (unless inappropriately coerced to unsigned).   *<c1p> will equal
4036      * *<c2p> if and only if <c1_utf8> and <c2_utf8> are the same. */
4037 
4038     const bool utf8_target = reginfo->is_utf8_target;
4039 
4040     UV c1 = (UV)CHRTEST_NOT_A_CP_1;
4041     UV c2 = (UV)CHRTEST_NOT_A_CP_2;
4042     bool use_chrtest_void = FALSE;
4043     const bool is_utf8_pat = reginfo->is_utf8_pat;
4044 
4045     /* Used when we have both utf8 input and utf8 output, to avoid converting
4046      * to/from code points */
4047     bool utf8_has_been_setup = FALSE;
4048 
4049     dVAR;
4050 
4051     U8 *pat = (U8*)STRING(text_node);
4052     U8 folded[UTF8_MAX_FOLD_CHAR_EXPAND * UTF8_MAXBYTES_CASE + 1] = { '\0' };
4053 
4054     if (OP(text_node) == EXACT || OP(text_node) == EXACTL) {
4055 
4056         /* In an exact node, only one thing can be matched, that first
4057          * character.  If both the pat and the target are UTF-8, we can just
4058          * copy the input to the output, avoiding finding the code point of
4059          * that character */
4060         if (!is_utf8_pat) {
4061             c2 = c1 = *pat;
4062         }
4063         else if (utf8_target) {
4064             Copy(pat, c1_utf8, UTF8SKIP(pat), U8);
4065             Copy(pat, c2_utf8, UTF8SKIP(pat), U8);
4066             utf8_has_been_setup = TRUE;
4067         }
4068         else {
4069             c2 = c1 = valid_utf8_to_uvchr(pat, NULL);
4070         }
4071     }
4072     else { /* an EXACTFish node */
4073         U8 *pat_end = pat + STR_LEN(text_node);
4074 
4075         /* An EXACTFL node has at least some characters unfolded, because what
4076          * they match is not known until now.  So, now is the time to fold
4077          * the first few of them, as many as are needed to determine 'c1' and
4078          * 'c2' later in the routine.  If the pattern isn't UTF-8, we only need
4079          * to fold if in a UTF-8 locale, and then only the Sharp S; everything
4080          * else is 1-1 and isn't assumed to be folded.  In a UTF-8 pattern, we
4081          * need to fold as many characters as a single character can fold to,
4082          * so that later we can check if the first ones are such a multi-char
4083          * fold.  But, in such a pattern only locale-problematic characters
4084          * aren't folded, so we can skip this completely if the first character
4085          * in the node isn't one of the tricky ones */
4086         if (OP(text_node) == EXACTFL) {
4087 
4088             if (! is_utf8_pat) {
4089                 if (IN_UTF8_CTYPE_LOCALE && *pat == LATIN_SMALL_LETTER_SHARP_S)
4090                 {
4091                     folded[0] = folded[1] = 's';
4092                     pat = folded;
4093                     pat_end = folded + 2;
4094                 }
4095             }
4096             else if (is_PROBLEMATIC_LOCALE_FOLDEDS_START_utf8(pat)) {
4097                 U8 *s = pat;
4098                 U8 *d = folded;
4099                 int i;
4100 
4101                 for (i = 0; i < UTF8_MAX_FOLD_CHAR_EXPAND && s < pat_end; i++) {
4102                     if (isASCII(*s)) {
4103                         *(d++) = (U8) toFOLD_LC(*s);
4104                         s++;
4105                     }
4106                     else {
4107                         STRLEN len;
4108                         _to_utf8_fold_flags(s,
4109                                             d,
4110                                             &len,
4111                                             FOLD_FLAGS_FULL | FOLD_FLAGS_LOCALE);
4112                         d += len;
4113                         s += UTF8SKIP(s);
4114                     }
4115                 }
4116 
4117                 pat = folded;
4118                 pat_end = d;
4119             }
4120         }
4121 
4122         if ((is_utf8_pat && is_MULTI_CHAR_FOLD_utf8_safe(pat, pat_end))
4123              || (!is_utf8_pat && is_MULTI_CHAR_FOLD_latin1_safe(pat, pat_end)))
4124         {
4125             /* Multi-character folds require more context to sort out.  Also
4126              * PL_utf8_foldclosures used below doesn't handle them, so have to
4127              * be handled outside this routine */
4128             use_chrtest_void = TRUE;
4129         }
4130         else { /* an EXACTFish node which doesn't begin with a multi-char fold */
4131             c1 = is_utf8_pat ? valid_utf8_to_uvchr(pat, NULL) : *pat;
4132             if (c1 > 255) {
4133                 /* Load the folds hash, if not already done */
4134                 SV** listp;
4135                 if (! PL_utf8_foldclosures) {
4136                     _load_PL_utf8_foldclosures();
4137                 }
4138 
4139                 /* The fold closures data structure is a hash with the keys
4140                  * being the UTF-8 of every character that is folded to, like
4141                  * 'k', and the values each an array of all code points that
4142                  * fold to its key.  e.g. [ 'k', 'K', KELVIN_SIGN ].
4143                  * Multi-character folds are not included */
4144                 if ((! (listp = hv_fetch(PL_utf8_foldclosures,
4145                                         (char *) pat,
4146                                         UTF8SKIP(pat),
4147                                         FALSE))))
4148                 {
4149                     /* Not found in the hash, therefore there are no folds
4150                     * containing it, so there is only a single character that
4151                     * could match */
4152                     c2 = c1;
4153                 }
4154                 else {  /* Does participate in folds */
4155                     AV* list = (AV*) *listp;
4156                     if (av_tindex_nomg(list) != 1) {
4157 
4158                         /* If there aren't exactly two folds to this, it is
4159                          * outside the scope of this function */
4160                         use_chrtest_void = TRUE;
4161                     }
4162                     else {  /* There are two.  Get them */
4163                         SV** c_p = av_fetch(list, 0, FALSE);
4164                         if (c_p == NULL) {
4165                             Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
4166                         }
4167                         c1 = SvUV(*c_p);
4168 
4169                         c_p = av_fetch(list, 1, FALSE);
4170                         if (c_p == NULL) {
4171                             Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
4172                         }
4173                         c2 = SvUV(*c_p);
4174 
4175                         /* Folds that cross the 255/256 boundary are forbidden
4176                          * if EXACTFL (and isnt a UTF8 locale), or EXACTFA and
4177                          * one is ASCIII.  Since the pattern character is above
4178                          * 255, and its only other match is below 256, the only
4179                          * legal match will be to itself.  We have thrown away
4180                          * the original, so have to compute which is the one
4181                          * above 255. */
4182                         if ((c1 < 256) != (c2 < 256)) {
4183                             if ((OP(text_node) == EXACTFL
4184                                  && ! IN_UTF8_CTYPE_LOCALE)
4185                                 || ((OP(text_node) == EXACTFA
4186                                     || OP(text_node) == EXACTFA_NO_TRIE)
4187                                     && (isASCII(c1) || isASCII(c2))))
4188                             {
4189                                 if (c1 < 256) {
4190                                     c1 = c2;
4191                                 }
4192                                 else {
4193                                     c2 = c1;
4194                                 }
4195                             }
4196                         }
4197                     }
4198                 }
4199             }
4200             else /* Here, c1 is <= 255 */
4201                 if (utf8_target
4202                     && HAS_NONLATIN1_FOLD_CLOSURE(c1)
4203                     && ( ! (OP(text_node) == EXACTFL && ! IN_UTF8_CTYPE_LOCALE))
4204                     && ((OP(text_node) != EXACTFA
4205                         && OP(text_node) != EXACTFA_NO_TRIE)
4206                         || ! isASCII(c1)))
4207             {
4208                 /* Here, there could be something above Latin1 in the target
4209                  * which folds to this character in the pattern.  All such
4210                  * cases except LATIN SMALL LETTER Y WITH DIAERESIS have more
4211                  * than two characters involved in their folds, so are outside
4212                  * the scope of this function */
4213                 if (UNLIKELY(c1 == LATIN_SMALL_LETTER_Y_WITH_DIAERESIS)) {
4214                     c2 = LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS;
4215                 }
4216                 else {
4217                     use_chrtest_void = TRUE;
4218                 }
4219             }
4220             else { /* Here nothing above Latin1 can fold to the pattern
4221                       character */
4222                 switch (OP(text_node)) {
4223 
4224                     case EXACTFL:   /* /l rules */
4225                         c2 = PL_fold_locale[c1];
4226                         break;
4227 
4228                     case EXACTF:   /* This node only generated for non-utf8
4229                                     patterns */
4230                         assert(! is_utf8_pat);
4231                         if (! utf8_target) {    /* /d rules */
4232                             c2 = PL_fold[c1];
4233                             break;
4234                         }
4235                         /* FALLTHROUGH */
4236                         /* /u rules for all these.  This happens to work for
4237                         * EXACTFA as nothing in Latin1 folds to ASCII */
4238                     case EXACTFA_NO_TRIE:   /* This node only generated for
4239                                             non-utf8 patterns */
4240                         assert(! is_utf8_pat);
4241                         /* FALLTHROUGH */
4242                     case EXACTFA:
4243                     case EXACTFU_SS:
4244                     case EXACTFU:
4245                         c2 = PL_fold_latin1[c1];
4246                         break;
4247 
4248                     default:
4249                         Perl_croak(aTHX_ "panic: Unexpected op %u", OP(text_node));
4250                         NOT_REACHED; /* NOTREACHED */
4251                 }
4252             }
4253         }
4254     }
4255 
4256     /* Here have figured things out.  Set up the returns */
4257     if (use_chrtest_void) {
4258         *c2p = *c1p = CHRTEST_VOID;
4259     }
4260     else if (utf8_target) {
4261         if (! utf8_has_been_setup) {    /* Don't have the utf8; must get it */
4262             uvchr_to_utf8(c1_utf8, c1);
4263             uvchr_to_utf8(c2_utf8, c2);
4264         }
4265 
4266         /* Invariants are stored in both the utf8 and byte outputs; Use
4267          * negative numbers otherwise for the byte ones.  Make sure that the
4268          * byte ones are the same iff the utf8 ones are the same */
4269         *c1p = (UTF8_IS_INVARIANT(*c1_utf8)) ? *c1_utf8 : CHRTEST_NOT_A_CP_1;
4270         *c2p = (UTF8_IS_INVARIANT(*c2_utf8))
4271                 ? *c2_utf8
4272                 : (c1 == c2)
4273                   ? CHRTEST_NOT_A_CP_1
4274                   : CHRTEST_NOT_A_CP_2;
4275     }
4276     else if (c1 > 255) {
4277        if (c2 > 255) {  /* both possibilities are above what a non-utf8 string
4278                            can represent */
4279            return FALSE;
4280        }
4281 
4282        *c1p = *c2p = c2;    /* c2 is the only representable value */
4283     }
4284     else {  /* c1 is representable; see about c2 */
4285        *c1p = c1;
4286        *c2p = (c2 < 256) ? c2 : c1;
4287     }
4288 
4289     return TRUE;
4290 }
4291 
4292 PERL_STATIC_INLINE bool
4293 S_isGCB(const GCB_enum before, const GCB_enum after)
4294 {
4295     /* returns a boolean indicating if there is a Grapheme Cluster Boundary
4296      * between the inputs.  See http://www.unicode.org/reports/tr29/ */
4297 
4298     return GCB_table[before][after];
4299 }
4300 
4301 /* Combining marks attach to most classes that precede them, but this defines
4302  * the exceptions (from TR14) */
4303 #define LB_CM_ATTACHES_TO(prev) ( ! (   prev == LB_EDGE                 \
4304                                      || prev == LB_Mandatory_Break      \
4305                                      || prev == LB_Carriage_Return      \
4306                                      || prev == LB_Line_Feed            \
4307                                      || prev == LB_Next_Line            \
4308                                      || prev == LB_Space                \
4309                                      || prev == LB_ZWSpace))
4310 
4311 STATIC bool
4312 S_isLB(pTHX_ LB_enum before,
4313              LB_enum after,
4314              const U8 * const strbeg,
4315              const U8 * const curpos,
4316              const U8 * const strend,
4317              const bool utf8_target)
4318 {
4319     U8 * temp_pos = (U8 *) curpos;
4320     LB_enum prev = before;
4321 
4322     /* Is the boundary between 'before' and 'after' line-breakable?
4323      * Most of this is just a table lookup of a generated table from Unicode
4324      * rules.  But some rules require context to decide, and so have to be
4325      * implemented in code */
4326 
4327     PERL_ARGS_ASSERT_ISLB;
4328 
4329     /* Rule numbers in the comments below are as of Unicode 8.0 */
4330 
4331   redo:
4332     before = prev;
4333     switch (LB_table[before][after]) {
4334         case LB_BREAKABLE:
4335             return TRUE;
4336 
4337         case LB_NOBREAK:
4338         case LB_NOBREAK_EVEN_WITH_SP_BETWEEN:
4339             return FALSE;
4340 
4341         case LB_SP_foo + LB_BREAKABLE:
4342         case LB_SP_foo + LB_NOBREAK:
4343         case LB_SP_foo + LB_NOBREAK_EVEN_WITH_SP_BETWEEN:
4344 
4345             /* When we have something following a SP, we have to look at the
4346              * context in order to know what to do.
4347              *
4348              * SP SP should not reach here because LB7: Do not break before
4349              * spaces.  (For two spaces in a row there is nothing that
4350              * overrides that) */
4351             assert(after != LB_Space);
4352 
4353             /* Here we have a space followed by a non-space.  Mostly this is a
4354              * case of LB18: "Break after spaces".  But there are complications
4355              * as the handling of spaces is somewhat tricky.  They are in a
4356              * number of rules, which have to be applied in priority order, but
4357              * something earlier in the string can cause a rule to be skipped
4358              * and a lower priority rule invoked.  A prime example is LB7 which
4359              * says don't break before a space.  But rule LB8 (lower priority)
4360              * says that the first break opportunity after a ZW is after any
4361              * span of spaces immediately after it.  If a ZW comes before a SP
4362              * in the input, rule LB8 applies, and not LB7.  Other such rules
4363              * involve combining marks which are rules 9 and 10, but they may
4364              * override higher priority rules if they come earlier in the
4365              * string.  Since we're doing random access into the middle of the
4366              * string, we have to look for rules that should get applied based
4367              * on both string position and priority.  Combining marks do not
4368              * attach to either ZW nor SP, so we don't have to consider them
4369              * until later.
4370              *
4371              * To check for LB8, we have to find the first non-space character
4372              * before this span of spaces */
4373             do {
4374                 prev = backup_one_LB(strbeg, &temp_pos, utf8_target);
4375             }
4376             while (prev == LB_Space);
4377 
4378             /* LB8 Break before any character following a zero-width space,
4379              * even if one or more spaces intervene.
4380              *      ZW SP* ÷
4381              * So if we have a ZW just before this span, and to get here this
4382              * is the final space in the span. */
4383             if (prev == LB_ZWSpace) {
4384                 return TRUE;
4385             }
4386 
4387             /* Here, not ZW SP+.  There are several rules that have higher
4388              * priority than LB18 and can be resolved now, as they don't depend
4389              * on anything earlier in the string (except ZW, which we have
4390              * already handled).  One of these rules is LB11 Do not break
4391              * before Word joiner, but we have specially encoded that in the
4392              * lookup table so it is caught by the single test below which
4393              * catches the other ones. */
4394             if (LB_table[LB_Space][after] - LB_SP_foo
4395                                             == LB_NOBREAK_EVEN_WITH_SP_BETWEEN)
4396             {
4397                 return FALSE;
4398             }
4399 
4400             /* If we get here, we have to XXX consider combining marks. */
4401             if (prev == LB_Combining_Mark) {
4402 
4403                 /* What happens with these depends on the character they
4404                  * follow.  */
4405                 do {
4406                     prev = backup_one_LB(strbeg, &temp_pos, utf8_target);
4407                 }
4408                 while (prev == LB_Combining_Mark);
4409 
4410                 /* Most times these attach to and inherit the characteristics
4411                  * of that character, but not always, and when not, they are to
4412                  * be treated as AL by rule LB10. */
4413                 if (! LB_CM_ATTACHES_TO(prev)) {
4414                     prev = LB_Alphabetic;
4415                 }
4416             }
4417 
4418             /* Here, we have the character preceding the span of spaces all set
4419              * up.  We follow LB18: "Break after spaces" unless the table shows
4420              * that is overriden */
4421             return LB_table[prev][after] != LB_NOBREAK_EVEN_WITH_SP_BETWEEN;
4422 
4423         case LB_CM_foo:
4424 
4425             /* We don't know how to treat the CM except by looking at the first
4426              * non-CM character preceding it */
4427             do {
4428                 prev = backup_one_LB(strbeg, &temp_pos, utf8_target);
4429             }
4430             while (prev == LB_Combining_Mark);
4431 
4432             /* Here, 'prev' is that first earlier non-CM character.  If the CM
4433              * attatches to it, then it inherits the behavior of 'prev'.  If it
4434              * doesn't attach, it is to be treated as an AL */
4435             if (! LB_CM_ATTACHES_TO(prev)) {
4436                 prev = LB_Alphabetic;
4437             }
4438 
4439             goto redo;
4440 
4441         case LB_HY_or_BA_then_foo + LB_BREAKABLE:
4442         case LB_HY_or_BA_then_foo + LB_NOBREAK:
4443 
4444             /* LB21a Don't break after Hebrew + Hyphen.
4445              * HL (HY | BA) × */
4446 
4447             if (backup_one_LB(strbeg, &temp_pos, utf8_target)
4448                                                           == LB_Hebrew_Letter)
4449             {
4450                 return FALSE;
4451             }
4452 
4453             return LB_table[prev][after] - LB_HY_or_BA_then_foo == LB_BREAKABLE;
4454 
4455         case LB_PR_or_PO_then_OP_or_HY + LB_BREAKABLE:
4456         case LB_PR_or_PO_then_OP_or_HY + LB_NOBREAK:
4457 
4458             /* LB25a (PR | PO) × ( OP | HY )? NU */
4459             if (advance_one_LB(&temp_pos, strend, utf8_target) == LB_Numeric) {
4460                 return FALSE;
4461             }
4462 
4463             return LB_table[prev][after] - LB_PR_or_PO_then_OP_or_HY
4464                                                                 == LB_BREAKABLE;
4465 
4466         case LB_SY_or_IS_then_various + LB_BREAKABLE:
4467         case LB_SY_or_IS_then_various + LB_NOBREAK:
4468         {
4469             /* LB25d NU (SY | IS)* × (NU | SY | IS | CL | CP ) */
4470 
4471             LB_enum temp = prev;
4472             do {
4473                 temp = backup_one_LB(strbeg, &temp_pos, utf8_target);
4474             }
4475             while (temp == LB_Break_Symbols || temp == LB_Infix_Numeric);
4476             if (temp == LB_Numeric) {
4477                 return FALSE;
4478             }
4479 
4480             return LB_table[prev][after] - LB_SY_or_IS_then_various
4481                                                                == LB_BREAKABLE;
4482         }
4483 
4484         case LB_various_then_PO_or_PR + LB_BREAKABLE:
4485         case LB_various_then_PO_or_PR + LB_NOBREAK:
4486         {
4487             /* LB25e NU (SY | IS)* (CL | CP)? × (PO | PR) */
4488 
4489             LB_enum temp = prev;
4490             if (temp == LB_Close_Punctuation || temp == LB_Close_Parenthesis)
4491             {
4492                 temp = backup_one_LB(strbeg, &temp_pos, utf8_target);
4493             }
4494             while (temp == LB_Break_Symbols || temp == LB_Infix_Numeric) {
4495                 temp = backup_one_LB(strbeg, &temp_pos, utf8_target);
4496             }
4497             if (temp == LB_Numeric) {
4498                 return FALSE;
4499             }
4500             return LB_various_then_PO_or_PR;
4501         }
4502 
4503         default:
4504             break;
4505     }
4506 
4507 #ifdef DEBUGGING
4508     Perl_re_printf( aTHX_  "Unhandled LB pair: LB_table[%d, %d] = %d\n",
4509                                   before, after, LB_table[before][after]);
4510     assert(0);
4511 #endif
4512     return TRUE;
4513 }
4514 
4515 STATIC LB_enum
4516 S_advance_one_LB(pTHX_ U8 ** curpos, const U8 * const strend, const bool utf8_target)
4517 {
4518     LB_enum lb;
4519 
4520     PERL_ARGS_ASSERT_ADVANCE_ONE_LB;
4521 
4522     if (*curpos >= strend) {
4523         return LB_EDGE;
4524     }
4525 
4526     if (utf8_target) {
4527         *curpos += UTF8SKIP(*curpos);
4528         if (*curpos >= strend) {
4529             return LB_EDGE;
4530         }
4531         lb = getLB_VAL_UTF8(*curpos, strend);
4532     }
4533     else {
4534         (*curpos)++;
4535         if (*curpos >= strend) {
4536             return LB_EDGE;
4537         }
4538         lb = getLB_VAL_CP(**curpos);
4539     }
4540 
4541     return lb;
4542 }
4543 
4544 STATIC LB_enum
4545 S_backup_one_LB(pTHX_ const U8 * const strbeg, U8 ** curpos, const bool utf8_target)
4546 {
4547     LB_enum lb;
4548 
4549     PERL_ARGS_ASSERT_BACKUP_ONE_LB;
4550 
4551     if (*curpos < strbeg) {
4552         return LB_EDGE;
4553     }
4554 
4555     if (utf8_target) {
4556         U8 * prev_char_pos = reghopmaybe3(*curpos, -1, strbeg);
4557         U8 * prev_prev_char_pos;
4558 
4559         if (! prev_char_pos) {
4560             return LB_EDGE;
4561         }
4562 
4563         if ((prev_prev_char_pos = reghopmaybe3((U8 *) prev_char_pos, -1, strbeg))) {
4564             lb = getLB_VAL_UTF8(prev_prev_char_pos, prev_char_pos);
4565             *curpos = prev_char_pos;
4566             prev_char_pos = prev_prev_char_pos;
4567         }
4568         else {
4569             *curpos = (U8 *) strbeg;
4570             return LB_EDGE;
4571         }
4572     }
4573     else {
4574         if (*curpos - 2 < strbeg) {
4575             *curpos = (U8 *) strbeg;
4576             return LB_EDGE;
4577         }
4578         (*curpos)--;
4579         lb = getLB_VAL_CP(*(*curpos - 1));
4580     }
4581 
4582     return lb;
4583 }
4584 
4585 STATIC bool
4586 S_isSB(pTHX_ SB_enum before,
4587              SB_enum after,
4588              const U8 * const strbeg,
4589              const U8 * const curpos,
4590              const U8 * const strend,
4591              const bool utf8_target)
4592 {
4593     /* returns a boolean indicating if there is a Sentence Boundary Break
4594      * between the inputs.  See http://www.unicode.org/reports/tr29/ */
4595 
4596     U8 * lpos = (U8 *) curpos;
4597     bool has_para_sep = FALSE;
4598     bool has_sp = FALSE;
4599 
4600     PERL_ARGS_ASSERT_ISSB;
4601 
4602     /* Break at the start and end of text.
4603         SB1.  sot  ÷
4604         SB2.  ÷  eot
4605       But unstated in Unicode is don't break if the text is empty */
4606     if (before == SB_EDGE || after == SB_EDGE) {
4607         return before != after;
4608     }
4609 
4610     /* SB 3: Do not break within CRLF. */
4611     if (before == SB_CR && after == SB_LF) {
4612         return FALSE;
4613     }
4614 
4615     /* Break after paragraph separators.  CR and LF are considered
4616      * so because Unicode views text as like word processing text where there
4617      * are no newlines except between paragraphs, and the word processor takes
4618      * care of wrapping without there being hard line-breaks in the text *./
4619        SB4.  Sep | CR | LF  ÷ */
4620     if (before == SB_Sep || before == SB_CR || before == SB_LF) {
4621         return TRUE;
4622     }
4623 
4624     /* Ignore Format and Extend characters, except after sot, Sep, CR, or LF.
4625      * (See Section 6.2, Replacing Ignore Rules.)
4626         SB5.  X (Extend | Format)*  →  X */
4627     if (after == SB_Extend || after == SB_Format) {
4628 
4629         /* Implied is that the these characters attach to everything
4630          * immediately prior to them except for those separator-type
4631          * characters.  And the rules earlier have already handled the case
4632          * when one of those immediately precedes the extend char */
4633         return FALSE;
4634     }
4635 
4636     if (before == SB_Extend || before == SB_Format) {
4637         U8 * temp_pos = lpos;
4638         const SB_enum backup = backup_one_SB(strbeg, &temp_pos, utf8_target);
4639         if (   backup != SB_EDGE
4640             && backup != SB_Sep
4641             && backup != SB_CR
4642             && backup != SB_LF)
4643         {
4644             before = backup;
4645             lpos = temp_pos;
4646         }
4647 
4648         /* Here, both 'before' and 'backup' are these types; implied is that we
4649          * don't break between them */
4650         if (backup == SB_Extend || backup == SB_Format) {
4651             return FALSE;
4652         }
4653     }
4654 
4655     /* Do not break after ambiguous terminators like period, if they are
4656      * immediately followed by a number or lowercase letter, if they are
4657      * between uppercase letters, if the first following letter (optionally
4658      * after certain punctuation) is lowercase, or if they are followed by
4659      * "continuation" punctuation such as comma, colon, or semicolon. For
4660      * example, a period may be an abbreviation or numeric period, and thus may
4661      * not mark the end of a sentence.
4662 
4663      * SB6. ATerm  ×  Numeric */
4664     if (before == SB_ATerm && after == SB_Numeric) {
4665         return FALSE;
4666     }
4667 
4668     /* SB7.  (Upper | Lower) ATerm  ×  Upper */
4669     if (before == SB_ATerm && after == SB_Upper) {
4670         U8 * temp_pos = lpos;
4671         SB_enum backup = backup_one_SB(strbeg, &temp_pos, utf8_target);
4672         if (backup == SB_Upper || backup == SB_Lower) {
4673             return FALSE;
4674         }
4675     }
4676 
4677     /* The remaining rules that aren't the final one, all require an STerm or
4678      * an ATerm after having backed up over some Close* Sp*, and in one case an
4679      * optional Paragraph separator, although one rule doesn't have any Sp's in it.
4680      * So do that backup now, setting flags if either Sp or a paragraph
4681      * separator are found */
4682 
4683     if (before == SB_Sep || before == SB_CR || before == SB_LF) {
4684         has_para_sep = TRUE;
4685         before = backup_one_SB(strbeg, &lpos, utf8_target);
4686     }
4687 
4688     if (before == SB_Sp) {
4689         has_sp = TRUE;
4690         do {
4691             before = backup_one_SB(strbeg, &lpos, utf8_target);
4692         }
4693         while (before == SB_Sp);
4694     }
4695 
4696     while (before == SB_Close) {
4697         before = backup_one_SB(strbeg, &lpos, utf8_target);
4698     }
4699 
4700     /* The next few rules apply only when the backed-up-to is an ATerm, and in
4701      * most cases an STerm */
4702     if (before == SB_STerm || before == SB_ATerm) {
4703 
4704         /* So, here the lhs matches
4705          *      (STerm | ATerm) Close* Sp* (Sep | CR | LF)?
4706          * and we have set flags if we found an Sp, or the optional Sep,CR,LF.
4707          * The rules that apply here are:
4708          *
4709          * SB8    ATerm Close* Sp*  ×  ( ¬(OLetter | Upper | Lower | Sep | CR
4710                                            | LF | STerm | ATerm) )* Lower
4711            SB8a  (STerm | ATerm) Close* Sp*  ×  (SContinue | STerm | ATerm)
4712            SB9   (STerm | ATerm) Close*  ×  (Close | Sp | Sep | CR | LF)
4713            SB10  (STerm | ATerm) Close* Sp*  ×  (Sp | Sep | CR | LF)
4714            SB11  (STerm | ATerm) Close* Sp* (Sep | CR | LF)?  ÷
4715          */
4716 
4717         /* And all but SB11 forbid having seen a paragraph separator */
4718         if (! has_para_sep) {
4719             if (before == SB_ATerm) {          /* SB8 */
4720                 U8 * rpos = (U8 *) curpos;
4721                 SB_enum later = after;
4722 
4723                 while (    later != SB_OLetter
4724                         && later != SB_Upper
4725                         && later != SB_Lower
4726                         && later != SB_Sep
4727                         && later != SB_CR
4728                         && later != SB_LF
4729                         && later != SB_STerm
4730                         && later != SB_ATerm
4731                         && later != SB_EDGE)
4732                 {
4733                     later = advance_one_SB(&rpos, strend, utf8_target);
4734                 }
4735                 if (later == SB_Lower) {
4736                     return FALSE;
4737                 }
4738             }
4739 
4740             if (   after == SB_SContinue    /* SB8a */
4741                 || after == SB_STerm
4742                 || after == SB_ATerm)
4743             {
4744                 return FALSE;
4745             }
4746 
4747             if (! has_sp) {     /* SB9 applies only if there was no Sp* */
4748                 if (   after == SB_Close
4749                     || after == SB_Sp
4750                     || after == SB_Sep
4751                     || after == SB_CR
4752                     || after == SB_LF)
4753                 {
4754                     return FALSE;
4755                 }
4756             }
4757 
4758             /* SB10.  This and SB9 could probably be combined some way, but khw
4759              * has decided to follow the Unicode rule book precisely for
4760              * simplified maintenance */
4761             if (   after == SB_Sp
4762                 || after == SB_Sep
4763                 || after == SB_CR
4764                 || after == SB_LF)
4765             {
4766                 return FALSE;
4767             }
4768         }
4769 
4770         /* SB11.  */
4771         return TRUE;
4772     }
4773 
4774     /* Otherwise, do not break.
4775     SB12.  Any  ×  Any */
4776 
4777     return FALSE;
4778 }
4779 
4780 STATIC SB_enum
4781 S_advance_one_SB(pTHX_ U8 ** curpos, const U8 * const strend, const bool utf8_target)
4782 {
4783     SB_enum sb;
4784 
4785     PERL_ARGS_ASSERT_ADVANCE_ONE_SB;
4786 
4787     if (*curpos >= strend) {
4788         return SB_EDGE;
4789     }
4790 
4791     if (utf8_target) {
4792         do {
4793             *curpos += UTF8SKIP(*curpos);
4794             if (*curpos >= strend) {
4795                 return SB_EDGE;
4796             }
4797             sb = getSB_VAL_UTF8(*curpos, strend);
4798         } while (sb == SB_Extend || sb == SB_Format);
4799     }
4800     else {
4801         do {
4802             (*curpos)++;
4803             if (*curpos >= strend) {
4804                 return SB_EDGE;
4805             }
4806             sb = getSB_VAL_CP(**curpos);
4807         } while (sb == SB_Extend || sb == SB_Format);
4808     }
4809 
4810     return sb;
4811 }
4812 
4813 STATIC SB_enum
4814 S_backup_one_SB(pTHX_ const U8 * const strbeg, U8 ** curpos, const bool utf8_target)
4815 {
4816     SB_enum sb;
4817 
4818     PERL_ARGS_ASSERT_BACKUP_ONE_SB;
4819 
4820     if (*curpos < strbeg) {
4821         return SB_EDGE;
4822     }
4823 
4824     if (utf8_target) {
4825         U8 * prev_char_pos = reghopmaybe3(*curpos, -1, strbeg);
4826         if (! prev_char_pos) {
4827             return SB_EDGE;
4828         }
4829 
4830         /* Back up over Extend and Format.  curpos is always just to the right
4831          * of the characater whose value we are getting */
4832         do {
4833             U8 * prev_prev_char_pos;
4834             if ((prev_prev_char_pos = reghopmaybe3((U8 *) prev_char_pos, -1,
4835                                                                       strbeg)))
4836             {
4837                 sb = getSB_VAL_UTF8(prev_prev_char_pos, prev_char_pos);
4838                 *curpos = prev_char_pos;
4839                 prev_char_pos = prev_prev_char_pos;
4840             }
4841             else {
4842                 *curpos = (U8 *) strbeg;
4843                 return SB_EDGE;
4844             }
4845         } while (sb == SB_Extend || sb == SB_Format);
4846     }
4847     else {
4848         do {
4849             if (*curpos - 2 < strbeg) {
4850                 *curpos = (U8 *) strbeg;
4851                 return SB_EDGE;
4852             }
4853             (*curpos)--;
4854             sb = getSB_VAL_CP(*(*curpos - 1));
4855         } while (sb == SB_Extend || sb == SB_Format);
4856     }
4857 
4858     return sb;
4859 }
4860 
4861 STATIC bool
4862 S_isWB(pTHX_ WB_enum previous,
4863              WB_enum before,
4864              WB_enum after,
4865              const U8 * const strbeg,
4866              const U8 * const curpos,
4867              const U8 * const strend,
4868              const bool utf8_target)
4869 {
4870     /*  Return a boolean as to if the boundary between 'before' and 'after' is
4871      *  a Unicode word break, using their published algorithm, but tailored for
4872      *  Perl by treating spans of white space as one unit.  Context may be
4873      *  needed to make this determination.  If the value for the character
4874      *  before 'before' is known, it is passed as 'previous'; otherwise that
4875      *  should be set to WB_UNKNOWN.  The other input parameters give the
4876      *  boundaries and current position in the matching of the string.  That
4877      *  is, 'curpos' marks the position where the character whose wb value is
4878      *  'after' begins.  See http://www.unicode.org/reports/tr29/ */
4879 
4880     U8 * before_pos = (U8 *) curpos;
4881     U8 * after_pos = (U8 *) curpos;
4882     WB_enum prev = before;
4883     WB_enum next;
4884 
4885     PERL_ARGS_ASSERT_ISWB;
4886 
4887     /* Rule numbers in the comments below are as of Unicode 8.0 */
4888 
4889   redo:
4890     before = prev;
4891     switch (WB_table[before][after]) {
4892         case WB_BREAKABLE:
4893             return TRUE;
4894 
4895         case WB_NOBREAK:
4896             return FALSE;
4897 
4898         case WB_hs_then_hs:     /* 2 horizontal spaces in a row */
4899             next = advance_one_WB(&after_pos, strend, utf8_target,
4900                                  FALSE /* Don't skip Extend nor Format */ );
4901             /* A space immediately preceeding an Extend or Format is attached
4902              * to by them, and hence gets separated from previous spaces.
4903              * Otherwise don't break between horizontal white space */
4904             return next == WB_Extend || next == WB_Format;
4905 
4906         /* WB4 Ignore Format and Extend characters, except when they appear at
4907          * the beginning of a region of text.  This code currently isn't
4908          * general purpose, but it works as the rules are currently and likely
4909          * to be laid out.  The reason it works is that when 'they appear at
4910          * the beginning of a region of text', the rule is to break before
4911          * them, just like any other character.  Therefore, the default rule
4912          * applies and we don't have to look in more depth.  Should this ever
4913          * change, we would have to have 2 'case' statements, like in the
4914          * rules below, and backup a single character (not spacing over the
4915          * extend ones) and then see if that is one of the region-end
4916          * characters and go from there */
4917         case WB_Ex_or_FO_then_foo:
4918             prev = backup_one_WB(&previous, strbeg, &before_pos, utf8_target);
4919             goto redo;
4920 
4921         case WB_DQ_then_HL + WB_BREAKABLE:
4922         case WB_DQ_then_HL + WB_NOBREAK:
4923 
4924             /* WB7c  Hebrew_Letter Double_Quote  ×  Hebrew_Letter */
4925 
4926             if (backup_one_WB(&previous, strbeg, &before_pos, utf8_target)
4927                                                             == WB_Hebrew_Letter)
4928             {
4929                 return FALSE;
4930             }
4931 
4932              return WB_table[before][after] - WB_DQ_then_HL == WB_BREAKABLE;
4933 
4934         case WB_HL_then_DQ + WB_BREAKABLE:
4935         case WB_HL_then_DQ + WB_NOBREAK:
4936 
4937             /* WB7b  Hebrew_Letter  ×  Double_Quote Hebrew_Letter */
4938 
4939             if (advance_one_WB(&after_pos, strend, utf8_target,
4940                                        TRUE /* Do skip Extend and Format */ )
4941                                                             == WB_Hebrew_Letter)
4942             {
4943                 return FALSE;
4944             }
4945 
4946             return WB_table[before][after] - WB_HL_then_DQ == WB_BREAKABLE;
4947 
4948         case WB_LE_or_HL_then_MB_or_ML_or_SQ + WB_NOBREAK:
4949         case WB_LE_or_HL_then_MB_or_ML_or_SQ + WB_BREAKABLE:
4950 
4951             /* WB6  (ALetter | Hebrew_Letter)  ×  (MidLetter | MidNumLet
4952              *       | Single_Quote) (ALetter | Hebrew_Letter) */
4953 
4954             next = advance_one_WB(&after_pos, strend, utf8_target,
4955                                        TRUE /* Do skip Extend and Format */ );
4956 
4957             if (next == WB_ALetter || next == WB_Hebrew_Letter)
4958             {
4959                 return FALSE;
4960             }
4961 
4962             return WB_table[before][after]
4963                             - WB_LE_or_HL_then_MB_or_ML_or_SQ == WB_BREAKABLE;
4964 
4965         case WB_MB_or_ML_or_SQ_then_LE_or_HL + WB_NOBREAK:
4966         case WB_MB_or_ML_or_SQ_then_LE_or_HL + WB_BREAKABLE:
4967 
4968             /* WB7  (ALetter | Hebrew_Letter) (MidLetter | MidNumLet
4969              *       | Single_Quote)  ×  (ALetter | Hebrew_Letter) */
4970 
4971             prev = backup_one_WB(&previous, strbeg, &before_pos, utf8_target);
4972             if (prev == WB_ALetter || prev == WB_Hebrew_Letter)
4973             {
4974                 return FALSE;
4975             }
4976 
4977             return WB_table[before][after]
4978                             - WB_MB_or_ML_or_SQ_then_LE_or_HL == WB_BREAKABLE;
4979 
4980         case WB_MB_or_MN_or_SQ_then_NU + WB_NOBREAK:
4981         case WB_MB_or_MN_or_SQ_then_NU + WB_BREAKABLE:
4982 
4983             /* WB11  Numeric (MidNum | (MidNumLet | Single_Quote))  ×  Numeric
4984              * */
4985 
4986             if (backup_one_WB(&previous, strbeg, &before_pos, utf8_target)
4987                                                             == WB_Numeric)
4988             {
4989                 return FALSE;
4990             }
4991 
4992             return WB_table[before][after]
4993                                 - WB_MB_or_MN_or_SQ_then_NU == WB_BREAKABLE;
4994 
4995         case WB_NU_then_MB_or_MN_or_SQ + WB_NOBREAK:
4996         case WB_NU_then_MB_or_MN_or_SQ + WB_BREAKABLE:
4997 
4998             /* WB12  Numeric  ×  (MidNum | MidNumLet | Single_Quote) Numeric */
4999 
5000             if (advance_one_WB(&after_pos, strend, utf8_target,
5001                                        TRUE /* Do skip Extend and Format */ )
5002                                                             == WB_Numeric)
5003             {
5004                 return FALSE;
5005             }
5006 
5007             return WB_table[before][after]
5008                                 - WB_NU_then_MB_or_MN_or_SQ == WB_BREAKABLE;
5009 
5010         default:
5011             break;
5012     }
5013 
5014 #ifdef DEBUGGING
5015     Perl_re_printf( aTHX_  "Unhandled WB pair: WB_table[%d, %d] = %d\n",
5016                                   before, after, WB_table[before][after]);
5017     assert(0);
5018 #endif
5019     return TRUE;
5020 }
5021 
5022 STATIC WB_enum
5023 S_advance_one_WB(pTHX_ U8 ** curpos,
5024                        const U8 * const strend,
5025                        const bool utf8_target,
5026                        const bool skip_Extend_Format)
5027 {
5028     WB_enum wb;
5029 
5030     PERL_ARGS_ASSERT_ADVANCE_ONE_WB;
5031 
5032     if (*curpos >= strend) {
5033         return WB_EDGE;
5034     }
5035 
5036     if (utf8_target) {
5037 
5038         /* Advance over Extend and Format */
5039         do {
5040             *curpos += UTF8SKIP(*curpos);
5041             if (*curpos >= strend) {
5042                 return WB_EDGE;
5043             }
5044             wb = getWB_VAL_UTF8(*curpos, strend);
5045         } while (    skip_Extend_Format
5046                  && (wb == WB_Extend || wb == WB_Format));
5047     }
5048     else {
5049         do {
5050             (*curpos)++;
5051             if (*curpos >= strend) {
5052                 return WB_EDGE;
5053             }
5054             wb = getWB_VAL_CP(**curpos);
5055         } while (    skip_Extend_Format
5056                  && (wb == WB_Extend || wb == WB_Format));
5057     }
5058 
5059     return wb;
5060 }
5061 
5062 STATIC WB_enum
5063 S_backup_one_WB(pTHX_ WB_enum * previous, const U8 * const strbeg, U8 ** curpos, const bool utf8_target)
5064 {
5065     WB_enum wb;
5066 
5067     PERL_ARGS_ASSERT_BACKUP_ONE_WB;
5068 
5069     /* If we know what the previous character's break value is, don't have
5070         * to look it up */
5071     if (*previous != WB_UNKNOWN) {
5072         wb = *previous;
5073 
5074         /* But we need to move backwards by one */
5075         if (utf8_target) {
5076             *curpos = reghopmaybe3(*curpos, -1, strbeg);
5077             if (! *curpos) {
5078                 *previous = WB_EDGE;
5079                 *curpos = (U8 *) strbeg;
5080             }
5081             else {
5082                 *previous = WB_UNKNOWN;
5083             }
5084         }
5085         else {
5086             (*curpos)--;
5087             *previous = (*curpos <= strbeg) ? WB_EDGE : WB_UNKNOWN;
5088         }
5089 
5090         /* And we always back up over these two types */
5091         if (wb != WB_Extend && wb != WB_Format) {
5092             return wb;
5093         }
5094     }
5095 
5096     if (*curpos < strbeg) {
5097         return WB_EDGE;
5098     }
5099 
5100     if (utf8_target) {
5101         U8 * prev_char_pos = reghopmaybe3(*curpos, -1, strbeg);
5102         if (! prev_char_pos) {
5103             return WB_EDGE;
5104         }
5105 
5106         /* Back up over Extend and Format.  curpos is always just to the right
5107          * of the characater whose value we are getting */
5108         do {
5109             U8 * prev_prev_char_pos;
5110             if ((prev_prev_char_pos = reghopmaybe3((U8 *) prev_char_pos,
5111                                                    -1,
5112                                                    strbeg)))
5113             {
5114                 wb = getWB_VAL_UTF8(prev_prev_char_pos, prev_char_pos);
5115                 *curpos = prev_char_pos;
5116                 prev_char_pos = prev_prev_char_pos;
5117             }
5118             else {
5119                 *curpos = (U8 *) strbeg;
5120                 return WB_EDGE;
5121             }
5122         } while (wb == WB_Extend || wb == WB_Format);
5123     }
5124     else {
5125         do {
5126             if (*curpos - 2 < strbeg) {
5127                 *curpos = (U8 *) strbeg;
5128                 return WB_EDGE;
5129             }
5130             (*curpos)--;
5131             wb = getWB_VAL_CP(*(*curpos - 1));
5132         } while (wb == WB_Extend || wb == WB_Format);
5133     }
5134 
5135     return wb;
5136 }
5137 
5138 #define EVAL_CLOSE_PAREN_IS(st,expr)                        \
5139 (                                                           \
5140     (   ( st )                                         ) && \
5141     (   ( st )->u.eval.close_paren                     ) && \
5142     ( ( ( st )->u.eval.close_paren ) == ( (expr) + 1 ) )    \
5143 )
5144 
5145 #define EVAL_CLOSE_PAREN_IS_TRUE(st,expr)                   \
5146 (                                                           \
5147     (   ( st )                                         ) && \
5148     (   ( st )->u.eval.close_paren                     ) && \
5149     (   ( expr )                                       ) && \
5150     ( ( ( st )->u.eval.close_paren ) == ( (expr) + 1 ) )    \
5151 )
5152 
5153 
5154 #define EVAL_CLOSE_PAREN_SET(st,expr) \
5155     (st)->u.eval.close_paren = ( (expr) + 1 )
5156 
5157 #define EVAL_CLOSE_PAREN_CLEAR(st) \
5158     (st)->u.eval.close_paren = 0
5159 
5160 /* returns -1 on failure, $+[0] on success */
5161 STATIC SSize_t
5162 S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
5163 {
5164 
5165 #if PERL_VERSION < 9 && !defined(PERL_CORE)
5166     dMY_CXT;
5167 #endif
5168     dVAR;
5169     const bool utf8_target = reginfo->is_utf8_target;
5170     const U32 uniflags = UTF8_ALLOW_DEFAULT;
5171     REGEXP *rex_sv = reginfo->prog;
5172     regexp *rex = ReANY(rex_sv);
5173     RXi_GET_DECL(rex,rexi);
5174     /* the current state. This is a cached copy of PL_regmatch_state */
5175     regmatch_state *st;
5176     /* cache heavy used fields of st in registers */
5177     regnode *scan;
5178     regnode *next;
5179     U32 n = 0;	/* general value; init to avoid compiler warning */
5180     SSize_t ln = 0; /* len or last;  init to avoid compiler warning */
5181     char *locinput = startpos;
5182     char *pushinput; /* where to continue after a PUSH */
5183     I32 nextchr;   /* is always set to UCHARAT(locinput), or -1 at EOS */
5184 
5185     bool result = 0;	    /* return value of S_regmatch */
5186     int depth = 0;	    /* depth of backtrack stack */
5187     U32 nochange_depth = 0; /* depth of GOSUB recursion with nochange */
5188     const U32 max_nochange_depth =
5189         (3 * rex->nparens > MAX_RECURSE_EVAL_NOCHANGE_DEPTH) ?
5190         3 * rex->nparens : MAX_RECURSE_EVAL_NOCHANGE_DEPTH;
5191     regmatch_state *yes_state = NULL; /* state to pop to on success of
5192 							    subpattern */
5193     /* mark_state piggy backs on the yes_state logic so that when we unwind
5194        the stack on success we can update the mark_state as we go */
5195     regmatch_state *mark_state = NULL; /* last mark state we have seen */
5196     regmatch_state *cur_eval = NULL; /* most recent EVAL_AB state */
5197     struct regmatch_state  *cur_curlyx = NULL; /* most recent curlyx */
5198     U32 state_num;
5199     bool no_final = 0;      /* prevent failure from backtracking? */
5200     bool do_cutgroup = 0;   /* no_final only until next branch/trie entry */
5201     char *startpoint = locinput;
5202     SV *popmark = NULL;     /* are we looking for a mark? */
5203     SV *sv_commit = NULL;   /* last mark name seen in failure */
5204     SV *sv_yes_mark = NULL; /* last mark name we have seen
5205                                during a successful match */
5206     U32 lastopen = 0;       /* last open we saw */
5207     bool has_cutgroup = RX_HAS_CUTGROUP(rex) ? 1 : 0;
5208     SV* const oreplsv = GvSVn(PL_replgv);
5209     /* these three flags are set by various ops to signal information to
5210      * the very next op. They have a useful lifetime of exactly one loop
5211      * iteration, and are not preserved or restored by state pushes/pops
5212      */
5213     bool sw = 0;	    /* the condition value in (?(cond)a|b) */
5214     bool minmod = 0;	    /* the next "{n,m}" is a "{n,m}?" */
5215     int logical = 0;	    /* the following EVAL is:
5216 				0: (?{...})
5217 				1: (?(?{...})X|Y)
5218 				2: (??{...})
5219 			       or the following IFMATCH/UNLESSM is:
5220 			        false: plain (?=foo)
5221 				true:  used as a condition: (?(?=foo))
5222 			    */
5223     PAD* last_pad = NULL;
5224     dMULTICALL;
5225     U8 gimme = G_SCALAR;
5226     CV *caller_cv = NULL;	/* who called us */
5227     CV *last_pushed_cv = NULL;	/* most recently called (?{}) CV */
5228     CHECKPOINT runops_cp;	/* savestack position before executing EVAL */
5229     U32 maxopenparen = 0;       /* max '(' index seen so far */
5230     int to_complement;  /* Invert the result? */
5231     _char_class_number classnum;
5232     bool is_utf8_pat = reginfo->is_utf8_pat;
5233     bool match = FALSE;
5234 
5235 /* Solaris Studio 12.3 messes up fetching PL_charclass['\n'] */
5236 #if (defined(__SUNPRO_C) && (__SUNPRO_C == 0x5120) && defined(__x86_64) && defined(USE_64_BIT_ALL))
5237 #  define SOLARIS_BAD_OPTIMIZER
5238     const U32 *pl_charclass_dup = PL_charclass;
5239 #  define PL_charclass pl_charclass_dup
5240 #endif
5241 
5242 #ifdef DEBUGGING
5243     GET_RE_DEBUG_FLAGS_DECL;
5244 #endif
5245 
5246     /* protect against undef(*^R) */
5247     SAVEFREESV(SvREFCNT_inc_simple_NN(oreplsv));
5248 
5249     /* shut up 'may be used uninitialized' compiler warnings for dMULTICALL */
5250     multicall_oldcatch = 0;
5251     PERL_UNUSED_VAR(multicall_cop);
5252 
5253     PERL_ARGS_ASSERT_REGMATCH;
5254 
5255     DEBUG_OPTIMISE_r( DEBUG_EXECUTE_r({
5256             Perl_re_printf( aTHX_ "regmatch start\n");
5257     }));
5258 
5259     st = PL_regmatch_state;
5260 
5261     /* Note that nextchr is a byte even in UTF */
5262     SET_nextchr;
5263     scan = prog;
5264     while (scan != NULL) {
5265 
5266 
5267 	next = scan + NEXT_OFF(scan);
5268 	if (next == scan)
5269 	    next = NULL;
5270 	state_num = OP(scan);
5271 
5272       reenter_switch:
5273         DEBUG_EXECUTE_r(
5274             if (state_num <= REGNODE_MAX) {
5275                 SV * const prop = sv_newmortal();
5276                 regnode *rnext = regnext(scan);
5277 
5278                 DUMP_EXEC_POS( locinput, scan, utf8_target, depth );
5279                 regprop(rex, prop, scan, reginfo, NULL);
5280                 Perl_re_printf( aTHX_
5281                     "%*s%"IVdf":%s(%"IVdf")\n",
5282                     INDENT_CHARS(depth), "",
5283                     (IV)(scan - rexi->program),
5284                     SvPVX_const(prop),
5285                     (PL_regkind[OP(scan)] == END || !rnext) ?
5286                         0 : (IV)(rnext - rexi->program));
5287             }
5288         );
5289 
5290         to_complement = 0;
5291 
5292         SET_nextchr;
5293         assert(nextchr < 256 && (nextchr >= 0 || nextchr == NEXTCHR_EOS));
5294 
5295 	switch (state_num) {
5296 	case SBOL: /*  /^../ and /\A../  */
5297 	    if (locinput == reginfo->strbeg)
5298 		break;
5299 	    sayNO;
5300 
5301 	case MBOL: /*  /^../m  */
5302 	    if (locinput == reginfo->strbeg ||
5303 		(!NEXTCHR_IS_EOS && locinput[-1] == '\n'))
5304 	    {
5305 		break;
5306 	    }
5307 	    sayNO;
5308 
5309 	case GPOS: /*  \G  */
5310 	    if (locinput == reginfo->ganch)
5311 		break;
5312 	    sayNO;
5313 
5314 	case KEEPS: /*   \K  */
5315 	    /* update the startpoint */
5316 	    st->u.keeper.val = rex->offs[0].start;
5317 	    rex->offs[0].start = locinput - reginfo->strbeg;
5318 	    PUSH_STATE_GOTO(KEEPS_next, next, locinput);
5319 	    NOT_REACHED; /* NOTREACHED */
5320 
5321 	case KEEPS_next_fail:
5322 	    /* rollback the start point change */
5323 	    rex->offs[0].start = st->u.keeper.val;
5324 	    sayNO_SILENT;
5325 	    NOT_REACHED; /* NOTREACHED */
5326 
5327 	case MEOL: /* /..$/m  */
5328 	    if (!NEXTCHR_IS_EOS && nextchr != '\n')
5329 		sayNO;
5330 	    break;
5331 
5332 	case SEOL: /* /..$/  */
5333 	    if (!NEXTCHR_IS_EOS && nextchr != '\n')
5334 		sayNO;
5335 	    if (reginfo->strend - locinput > 1)
5336 		sayNO;
5337 	    break;
5338 
5339 	case EOS: /*  \z  */
5340 	    if (!NEXTCHR_IS_EOS)
5341 		sayNO;
5342 	    break;
5343 
5344 	case SANY: /*  /./s  */
5345 	    if (NEXTCHR_IS_EOS)
5346 		sayNO;
5347             goto increment_locinput;
5348 
5349 	case REG_ANY: /*  /./  */
5350 	    if ((NEXTCHR_IS_EOS) || nextchr == '\n')
5351 		sayNO;
5352             goto increment_locinput;
5353 
5354 
5355 #undef  ST
5356 #define ST st->u.trie
5357         case TRIEC: /* (ab|cd) with known charclass */
5358             /* In this case the charclass data is available inline so
5359                we can fail fast without a lot of extra overhead.
5360              */
5361             if(!NEXTCHR_IS_EOS && !ANYOF_BITMAP_TEST(scan, nextchr)) {
5362                 DEBUG_EXECUTE_r(
5363                     Perl_re_exec_indentf( aTHX_  "%sfailed to match trie start class...%s\n",
5364                               depth, PL_colors[4], PL_colors[5])
5365                 );
5366                 sayNO_SILENT;
5367                 NOT_REACHED; /* NOTREACHED */
5368             }
5369             /* FALLTHROUGH */
5370 	case TRIE:  /* (ab|cd)  */
5371 	    /* the basic plan of execution of the trie is:
5372 	     * At the beginning, run though all the states, and
5373 	     * find the longest-matching word. Also remember the position
5374 	     * of the shortest matching word. For example, this pattern:
5375 	     *    1  2 3 4    5
5376 	     *    ab|a|x|abcd|abc
5377 	     * when matched against the string "abcde", will generate
5378 	     * accept states for all words except 3, with the longest
5379 	     * matching word being 4, and the shortest being 2 (with
5380 	     * the position being after char 1 of the string).
5381 	     *
5382 	     * Then for each matching word, in word order (i.e. 1,2,4,5),
5383 	     * we run the remainder of the pattern; on each try setting
5384 	     * the current position to the character following the word,
5385 	     * returning to try the next word on failure.
5386 	     *
5387 	     * We avoid having to build a list of words at runtime by
5388 	     * using a compile-time structure, wordinfo[].prev, which
5389 	     * gives, for each word, the previous accepting word (if any).
5390 	     * In the case above it would contain the mappings 1->2, 2->0,
5391 	     * 3->0, 4->5, 5->1.  We can use this table to generate, from
5392 	     * the longest word (4 above), a list of all words, by
5393 	     * following the list of prev pointers; this gives us the
5394 	     * unordered list 4,5,1,2. Then given the current word we have
5395 	     * just tried, we can go through the list and find the
5396 	     * next-biggest word to try (so if we just failed on word 2,
5397 	     * the next in the list is 4).
5398 	     *
5399 	     * Since at runtime we don't record the matching position in
5400 	     * the string for each word, we have to work that out for
5401 	     * each word we're about to process. The wordinfo table holds
5402 	     * the character length of each word; given that we recorded
5403 	     * at the start: the position of the shortest word and its
5404 	     * length in chars, we just need to move the pointer the
5405 	     * difference between the two char lengths. Depending on
5406 	     * Unicode status and folding, that's cheap or expensive.
5407 	     *
5408 	     * This algorithm is optimised for the case where are only a
5409 	     * small number of accept states, i.e. 0,1, or maybe 2.
5410 	     * With lots of accepts states, and having to try all of them,
5411 	     * it becomes quadratic on number of accept states to find all
5412 	     * the next words.
5413 	     */
5414 
5415 	    {
5416                 /* what type of TRIE am I? (utf8 makes this contextual) */
5417                 DECL_TRIE_TYPE(scan);
5418 
5419                 /* what trie are we using right now */
5420 		reg_trie_data * const trie
5421         	    = (reg_trie_data*)rexi->data->data[ ARG( scan ) ];
5422 		HV * widecharmap = MUTABLE_HV(rexi->data->data[ ARG( scan ) + 1 ]);
5423                 U32 state = trie->startstate;
5424 
5425                 if (scan->flags == EXACTL || scan->flags == EXACTFLU8) {
5426                     _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
5427                     if (utf8_target
5428                         && UTF8_IS_ABOVE_LATIN1(nextchr)
5429                         && scan->flags == EXACTL)
5430                     {
5431                         /* We only output for EXACTL, as we let the folder
5432                          * output this message for EXACTFLU8 to avoid
5433                          * duplication */
5434                         _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(locinput,
5435                                                                reginfo->strend);
5436                     }
5437                 }
5438                 if (   trie->bitmap
5439                     && (NEXTCHR_IS_EOS || !TRIE_BITMAP_TEST(trie, nextchr)))
5440                 {
5441         	    if (trie->states[ state ].wordnum) {
5442         	         DEBUG_EXECUTE_r(
5443                             Perl_re_exec_indentf( aTHX_  "%smatched empty string...%s\n",
5444                                           depth, PL_colors[4], PL_colors[5])
5445                         );
5446 			if (!trie->jump)
5447 			    break;
5448         	    } else {
5449         	        DEBUG_EXECUTE_r(
5450                             Perl_re_exec_indentf( aTHX_  "%sfailed to match trie start class...%s\n",
5451                                           depth, PL_colors[4], PL_colors[5])
5452                         );
5453         	        sayNO_SILENT;
5454         	   }
5455                 }
5456 
5457             {
5458 		U8 *uc = ( U8* )locinput;
5459 
5460 		STRLEN len = 0;
5461 		STRLEN foldlen = 0;
5462 		U8 *uscan = (U8*)NULL;
5463 		U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
5464 		U32 charcount = 0; /* how many input chars we have matched */
5465 		U32 accepted = 0; /* have we seen any accepting states? */
5466 
5467 		ST.jump = trie->jump;
5468 		ST.me = scan;
5469 		ST.firstpos = NULL;
5470 		ST.longfold = FALSE; /* char longer if folded => it's harder */
5471 		ST.nextword = 0;
5472 
5473 		/* fully traverse the TRIE; note the position of the
5474 		   shortest accept state and the wordnum of the longest
5475 		   accept state */
5476 
5477 		while ( state && uc <= (U8*)(reginfo->strend) ) {
5478                     U32 base = trie->states[ state ].trans.base;
5479                     UV uvc = 0;
5480                     U16 charid = 0;
5481 		    U16 wordnum;
5482                     wordnum = trie->states[ state ].wordnum;
5483 
5484 		    if (wordnum) { /* it's an accept state */
5485 			if (!accepted) {
5486 			    accepted = 1;
5487 			    /* record first match position */
5488 			    if (ST.longfold) {
5489 				ST.firstpos = (U8*)locinput;
5490 				ST.firstchars = 0;
5491 			    }
5492 			    else {
5493 				ST.firstpos = uc;
5494 				ST.firstchars = charcount;
5495 			    }
5496 			}
5497 			if (!ST.nextword || wordnum < ST.nextword)
5498 			    ST.nextword = wordnum;
5499 			ST.topword = wordnum;
5500 		    }
5501 
5502 		    DEBUG_TRIE_EXECUTE_r({
5503                                 DUMP_EXEC_POS( (char *)uc, scan, utf8_target, depth );
5504                                 Perl_re_exec_indentf( aTHX_
5505                                     "%sState: %4"UVxf" Accepted: %c ",
5506                                     depth, PL_colors[4],
5507 			            (UV)state, (accepted ? 'Y' : 'N'));
5508 		    });
5509 
5510 		    /* read a char and goto next state */
5511 		    if ( base && (foldlen || uc < (U8*)(reginfo->strend))) {
5512 			I32 offset;
5513 			REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc,
5514 					     uscan, len, uvc, charid, foldlen,
5515 					     foldbuf, uniflags);
5516 			charcount++;
5517 			if (foldlen>0)
5518 			    ST.longfold = TRUE;
5519 			if (charid &&
5520 			     ( ((offset =
5521 			      base + charid - 1 - trie->uniquecharcount)) >= 0)
5522 
5523 			     && ((U32)offset < trie->lasttrans)
5524 			     && trie->trans[offset].check == state)
5525 			{
5526 			    state = trie->trans[offset].next;
5527 			}
5528 			else {
5529 			    state = 0;
5530 			}
5531 			uc += len;
5532 
5533 		    }
5534 		    else {
5535 			state = 0;
5536 		    }
5537 		    DEBUG_TRIE_EXECUTE_r(
5538                         Perl_re_printf( aTHX_
5539 		            "Charid:%3x CP:%4"UVxf" After State: %4"UVxf"%s\n",
5540 		            charid, uvc, (UV)state, PL_colors[5] );
5541 		    );
5542 		}
5543 		if (!accepted)
5544 		   sayNO;
5545 
5546 		/* calculate total number of accept states */
5547 		{
5548 		    U16 w = ST.topword;
5549 		    accepted = 0;
5550 		    while (w) {
5551 			w = trie->wordinfo[w].prev;
5552 			accepted++;
5553 		    }
5554 		    ST.accepted = accepted;
5555 		}
5556 
5557 		DEBUG_EXECUTE_r(
5558                     Perl_re_exec_indentf( aTHX_  "%sgot %"IVdf" possible matches%s\n",
5559                         depth,
5560 			PL_colors[4], (IV)ST.accepted, PL_colors[5] );
5561 		);
5562 		goto trie_first_try; /* jump into the fail handler */
5563 	    }}
5564 	    NOT_REACHED; /* NOTREACHED */
5565 
5566 	case TRIE_next_fail: /* we failed - try next alternative */
5567         {
5568             U8 *uc;
5569             if ( ST.jump) {
5570                 REGCP_UNWIND(ST.cp);
5571                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
5572 	    }
5573 	    if (!--ST.accepted) {
5574 	        DEBUG_EXECUTE_r({
5575                     Perl_re_exec_indentf( aTHX_  "%sTRIE failed...%s\n",
5576                         depth,
5577 			PL_colors[4],
5578 			PL_colors[5] );
5579 		});
5580 		sayNO_SILENT;
5581 	    }
5582 	    {
5583 		/* Find next-highest word to process.  Note that this code
5584 		 * is O(N^2) per trie run (O(N) per branch), so keep tight */
5585 		U16 min = 0;
5586 		U16 word;
5587 		U16 const nextword = ST.nextword;
5588 		reg_trie_wordinfo * const wordinfo
5589 		    = ((reg_trie_data*)rexi->data->data[ARG(ST.me)])->wordinfo;
5590 		for (word=ST.topword; word; word=wordinfo[word].prev) {
5591 		    if (word > nextword && (!min || word < min))
5592 			min = word;
5593 		}
5594 		ST.nextword = min;
5595 	    }
5596 
5597           trie_first_try:
5598             if (do_cutgroup) {
5599                 do_cutgroup = 0;
5600                 no_final = 0;
5601             }
5602 
5603             if ( ST.jump) {
5604                 ST.lastparen = rex->lastparen;
5605                 ST.lastcloseparen = rex->lastcloseparen;
5606 	        REGCP_SET(ST.cp);
5607             }
5608 
5609 	    /* find start char of end of current word */
5610 	    {
5611 		U32 chars; /* how many chars to skip */
5612 		reg_trie_data * const trie
5613 		    = (reg_trie_data*)rexi->data->data[ARG(ST.me)];
5614 
5615 		assert((trie->wordinfo[ST.nextword].len - trie->prefixlen)
5616 			    >=  ST.firstchars);
5617 		chars = (trie->wordinfo[ST.nextword].len - trie->prefixlen)
5618 			    - ST.firstchars;
5619 		uc = ST.firstpos;
5620 
5621 		if (ST.longfold) {
5622 		    /* the hard option - fold each char in turn and find
5623 		     * its folded length (which may be different */
5624 		    U8 foldbuf[UTF8_MAXBYTES_CASE + 1];
5625 		    STRLEN foldlen;
5626 		    STRLEN len;
5627 		    UV uvc;
5628 		    U8 *uscan;
5629 
5630 		    while (chars) {
5631 			if (utf8_target) {
5632 			    uvc = utf8n_to_uvchr((U8*)uc, UTF8_MAXLEN, &len,
5633 						    uniflags);
5634 			    uc += len;
5635 			}
5636 			else {
5637 			    uvc = *uc;
5638 			    uc++;
5639 			}
5640 			uvc = to_uni_fold(uvc, foldbuf, &foldlen);
5641 			uscan = foldbuf;
5642 			while (foldlen) {
5643 			    if (!--chars)
5644 				break;
5645 			    uvc = utf8n_to_uvchr(uscan, UTF8_MAXLEN, &len,
5646 					    uniflags);
5647 			    uscan += len;
5648 			    foldlen -= len;
5649 			}
5650 		    }
5651 		}
5652 		else {
5653 		    if (utf8_target)
5654 			while (chars--)
5655 			    uc += UTF8SKIP(uc);
5656 		    else
5657 			uc += chars;
5658 		}
5659 	    }
5660 
5661 	    scan = ST.me + ((ST.jump && ST.jump[ST.nextword])
5662 			    ? ST.jump[ST.nextword]
5663 			    : NEXT_OFF(ST.me));
5664 
5665 	    DEBUG_EXECUTE_r({
5666                 Perl_re_exec_indentf( aTHX_  "%sTRIE matched word #%d, continuing%s\n",
5667                     depth,
5668 		    PL_colors[4],
5669 		    ST.nextword,
5670 		    PL_colors[5]
5671 		    );
5672 	    });
5673 
5674 	    if (ST.accepted > 1 || has_cutgroup) {
5675 		PUSH_STATE_GOTO(TRIE_next, scan, (char*)uc);
5676 		NOT_REACHED; /* NOTREACHED */
5677 	    }
5678 	    /* only one choice left - just continue */
5679 	    DEBUG_EXECUTE_r({
5680 		AV *const trie_words
5681 		    = MUTABLE_AV(rexi->data->data[ARG(ST.me)+TRIE_WORDS_OFFSET]);
5682 		SV ** const tmp = trie_words
5683                         ? av_fetch(trie_words, ST.nextword - 1, 0) : NULL;
5684 		SV *sv= tmp ? sv_newmortal() : NULL;
5685 
5686                 Perl_re_exec_indentf( aTHX_  "%sonly one match left, short-circuiting: #%d <%s>%s\n",
5687                     depth, PL_colors[4],
5688 		    ST.nextword,
5689 		    tmp ? pv_pretty(sv, SvPV_nolen_const(*tmp), SvCUR(*tmp), 0,
5690 			    PL_colors[0], PL_colors[1],
5691 			    (SvUTF8(*tmp) ? PERL_PV_ESCAPE_UNI : 0)|PERL_PV_ESCAPE_NONASCII
5692 			)
5693 		    : "not compiled under -Dr",
5694 		    PL_colors[5] );
5695 	    });
5696 
5697 	    locinput = (char*)uc;
5698 	    continue; /* execute rest of RE */
5699             /* NOTREACHED */
5700         }
5701 #undef  ST
5702 
5703 	case EXACTL:             /*  /abc/l       */
5704             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
5705 
5706             /* Complete checking would involve going through every character
5707              * matched by the string to see if any is above latin1.  But the
5708              * comparision otherwise might very well be a fast assembly
5709              * language routine, and I (khw) don't think slowing things down
5710              * just to check for this warning is worth it.  So this just checks
5711              * the first character */
5712             if (utf8_target && UTF8_IS_ABOVE_LATIN1(*locinput)) {
5713                 _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(locinput, reginfo->strend);
5714             }
5715             /* FALLTHROUGH */
5716 	case EXACT: {            /*  /abc/        */
5717 	    char *s = STRING(scan);
5718 	    ln = STR_LEN(scan);
5719 	    if (utf8_target != is_utf8_pat) {
5720 		/* The target and the pattern have differing utf8ness. */
5721 		char *l = locinput;
5722 		const char * const e = s + ln;
5723 
5724 		if (utf8_target) {
5725                     /* The target is utf8, the pattern is not utf8.
5726                      * Above-Latin1 code points can't match the pattern;
5727                      * invariants match exactly, and the other Latin1 ones need
5728                      * to be downgraded to a single byte in order to do the
5729                      * comparison.  (If we could be confident that the target
5730                      * is not malformed, this could be refactored to have fewer
5731                      * tests by just assuming that if the first bytes match, it
5732                      * is an invariant, but there are tests in the test suite
5733                      * dealing with (??{...}) which violate this) */
5734 		    while (s < e) {
5735 			if (l >= reginfo->strend
5736                             || UTF8_IS_ABOVE_LATIN1(* (U8*) l))
5737                         {
5738                             sayNO;
5739                         }
5740                         if (UTF8_IS_INVARIANT(*(U8*)l)) {
5741 			    if (*l != *s) {
5742                                 sayNO;
5743                             }
5744                             l++;
5745                         }
5746                         else {
5747                             if (EIGHT_BIT_UTF8_TO_NATIVE(*l, *(l+1)) != * (U8*) s)
5748                             {
5749                                 sayNO;
5750                             }
5751                             l += 2;
5752                         }
5753 			s++;
5754 		    }
5755 		}
5756 		else {
5757 		    /* The target is not utf8, the pattern is utf8. */
5758 		    while (s < e) {
5759                         if (l >= reginfo->strend
5760                             || UTF8_IS_ABOVE_LATIN1(* (U8*) s))
5761                         {
5762                             sayNO;
5763                         }
5764                         if (UTF8_IS_INVARIANT(*(U8*)s)) {
5765 			    if (*s != *l) {
5766                                 sayNO;
5767                             }
5768                             s++;
5769                         }
5770                         else {
5771                             if (EIGHT_BIT_UTF8_TO_NATIVE(*s, *(s+1)) != * (U8*) l)
5772                             {
5773                                 sayNO;
5774                             }
5775                             s += 2;
5776                         }
5777 			l++;
5778 		    }
5779 		}
5780 		locinput = l;
5781 	    }
5782             else {
5783                 /* The target and the pattern have the same utf8ness. */
5784                 /* Inline the first character, for speed. */
5785                 if (reginfo->strend - locinput < ln
5786                     || UCHARAT(s) != nextchr
5787                     || (ln > 1 && memNE(s, locinput, ln)))
5788                 {
5789                     sayNO;
5790                 }
5791                 locinput += ln;
5792             }
5793 	    break;
5794 	    }
5795 
5796 	case EXACTFL: {          /*  /abc/il      */
5797 	    re_fold_t folder;
5798 	    const U8 * fold_array;
5799 	    const char * s;
5800 	    U32 fold_utf8_flags;
5801 
5802             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
5803             folder = foldEQ_locale;
5804             fold_array = PL_fold_locale;
5805 	    fold_utf8_flags = FOLDEQ_LOCALE;
5806 	    goto do_exactf;
5807 
5808         case EXACTFLU8:           /*  /abc/il; but all 'abc' are above 255, so
5809                                       is effectively /u; hence to match, target
5810                                       must be UTF-8. */
5811             if (! utf8_target) {
5812                 sayNO;
5813             }
5814             fold_utf8_flags =  FOLDEQ_LOCALE | FOLDEQ_S1_ALREADY_FOLDED
5815                                              | FOLDEQ_S1_FOLDS_SANE;
5816 	    folder = foldEQ_latin1;
5817 	    fold_array = PL_fold_latin1;
5818 	    goto do_exactf;
5819 
5820 	case EXACTFU_SS:         /*  /\x{df}/iu   */
5821 	case EXACTFU:            /*  /abc/iu      */
5822 	    folder = foldEQ_latin1;
5823 	    fold_array = PL_fold_latin1;
5824 	    fold_utf8_flags = is_utf8_pat ? FOLDEQ_S1_ALREADY_FOLDED : 0;
5825 	    goto do_exactf;
5826 
5827         case EXACTFA_NO_TRIE:   /* This node only generated for non-utf8
5828                                    patterns */
5829             assert(! is_utf8_pat);
5830             /* FALLTHROUGH */
5831 	case EXACTFA:            /*  /abc/iaa     */
5832 	    folder = foldEQ_latin1;
5833 	    fold_array = PL_fold_latin1;
5834 	    fold_utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
5835 	    goto do_exactf;
5836 
5837         case EXACTF:             /*  /abc/i    This node only generated for
5838                                                non-utf8 patterns */
5839             assert(! is_utf8_pat);
5840 	    folder = foldEQ;
5841 	    fold_array = PL_fold;
5842 	    fold_utf8_flags = 0;
5843 
5844 	  do_exactf:
5845 	    s = STRING(scan);
5846 	    ln = STR_LEN(scan);
5847 
5848 	    if (utf8_target
5849                 || is_utf8_pat
5850                 || state_num == EXACTFU_SS
5851                 || (state_num == EXACTFL && IN_UTF8_CTYPE_LOCALE))
5852             {
5853 	      /* Either target or the pattern are utf8, or has the issue where
5854 	       * the fold lengths may differ. */
5855 		const char * const l = locinput;
5856 		char *e = reginfo->strend;
5857 
5858 		if (! foldEQ_utf8_flags(s, 0,  ln, is_utf8_pat,
5859 			                l, &e, 0,  utf8_target, fold_utf8_flags))
5860 		{
5861 		    sayNO;
5862 		}
5863 		locinput = e;
5864 		break;
5865 	    }
5866 
5867 	    /* Neither the target nor the pattern are utf8 */
5868 	    if (UCHARAT(s) != nextchr
5869                 && !NEXTCHR_IS_EOS
5870 		&& UCHARAT(s) != fold_array[nextchr])
5871 	    {
5872 		sayNO;
5873 	    }
5874 	    if (reginfo->strend - locinput < ln)
5875 		sayNO;
5876 	    if (ln > 1 && ! folder(s, locinput, ln))
5877 		sayNO;
5878 	    locinput += ln;
5879 	    break;
5880 	}
5881 
5882 	case NBOUNDL: /*  /\B/l  */
5883             to_complement = 1;
5884             /* FALLTHROUGH */
5885 
5886 	case BOUNDL:  /*  /\b/l  */
5887         {
5888             bool b1, b2;
5889             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
5890 
5891             if (FLAGS(scan) != TRADITIONAL_BOUND) {
5892                 if (! IN_UTF8_CTYPE_LOCALE) {
5893                     Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
5894                                                 B_ON_NON_UTF8_LOCALE_IS_WRONG);
5895                 }
5896                 goto boundu;
5897             }
5898 
5899 	    if (utf8_target) {
5900 		if (locinput == reginfo->strbeg)
5901 		    b1 = isWORDCHAR_LC('\n');
5902 		else {
5903                     b1 = isWORDCHAR_LC_utf8(reghop3((U8*)locinput, -1,
5904                                                         (U8*)(reginfo->strbeg)));
5905 		}
5906                 b2 = (NEXTCHR_IS_EOS)
5907                     ? isWORDCHAR_LC('\n')
5908                     : isWORDCHAR_LC_utf8((U8*)locinput);
5909 	    }
5910 	    else { /* Here the string isn't utf8 */
5911 		b1 = (locinput == reginfo->strbeg)
5912                      ? isWORDCHAR_LC('\n')
5913                      : isWORDCHAR_LC(UCHARAT(locinput - 1));
5914                 b2 = (NEXTCHR_IS_EOS)
5915                     ? isWORDCHAR_LC('\n')
5916                     : isWORDCHAR_LC(nextchr);
5917 	    }
5918             if (to_complement ^ (b1 == b2)) {
5919                 sayNO;
5920             }
5921 	    break;
5922         }
5923 
5924 	case NBOUND:  /*  /\B/   */
5925             to_complement = 1;
5926             /* FALLTHROUGH */
5927 
5928 	case BOUND:   /*  /\b/   */
5929 	    if (utf8_target) {
5930                 goto bound_utf8;
5931             }
5932             goto bound_ascii_match_only;
5933 
5934 	case NBOUNDA: /*  /\B/a  */
5935             to_complement = 1;
5936             /* FALLTHROUGH */
5937 
5938 	case BOUNDA:  /*  /\b/a  */
5939         {
5940             bool b1, b2;
5941 
5942           bound_ascii_match_only:
5943             /* Here the string isn't utf8, or is utf8 and only ascii characters
5944              * are to match \w.  In the latter case looking at the byte just
5945              * prior to the current one may be just the final byte of a
5946              * multi-byte character.  This is ok.  There are two cases:
5947              * 1) it is a single byte character, and then the test is doing
5948              *    just what it's supposed to.
5949              * 2) it is a multi-byte character, in which case the final byte is
5950              *    never mistakable for ASCII, and so the test will say it is
5951              *    not a word character, which is the correct answer. */
5952             b1 = (locinput == reginfo->strbeg)
5953                  ? isWORDCHAR_A('\n')
5954                  : isWORDCHAR_A(UCHARAT(locinput - 1));
5955             b2 = (NEXTCHR_IS_EOS)
5956                 ? isWORDCHAR_A('\n')
5957                 : isWORDCHAR_A(nextchr);
5958             if (to_complement ^ (b1 == b2)) {
5959                 sayNO;
5960             }
5961 	    break;
5962         }
5963 
5964 	case NBOUNDU: /*  /\B/u  */
5965             to_complement = 1;
5966             /* FALLTHROUGH */
5967 
5968 	case BOUNDU:  /*  /\b/u  */
5969 
5970           boundu:
5971             if (UNLIKELY(reginfo->strbeg >= reginfo->strend)) {
5972                 match = FALSE;
5973             }
5974             else if (utf8_target) {
5975               bound_utf8:
5976                 switch((bound_type) FLAGS(scan)) {
5977                     case TRADITIONAL_BOUND:
5978                     {
5979                         bool b1, b2;
5980                         b1 = (locinput == reginfo->strbeg)
5981                              ? 0 /* isWORDCHAR_L1('\n') */
5982                              : isWORDCHAR_utf8(reghop3((U8*)locinput, -1,
5983                                                                 (U8*)(reginfo->strbeg)));
5984                         b2 = (NEXTCHR_IS_EOS)
5985                             ? 0 /* isWORDCHAR_L1('\n') */
5986                             : isWORDCHAR_utf8((U8*)locinput);
5987                         match = cBOOL(b1 != b2);
5988                         break;
5989                     }
5990                     case GCB_BOUND:
5991                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
5992                             match = TRUE; /* GCB always matches at begin and
5993                                              end */
5994                         }
5995                         else {
5996                             /* Find the gcb values of previous and current
5997                              * chars, then see if is a break point */
5998                             match = isGCB(getGCB_VAL_UTF8(
5999                                                 reghop3((U8*)locinput,
6000                                                         -1,
6001                                                         (U8*)(reginfo->strbeg)),
6002                                                 (U8*) reginfo->strend),
6003                                           getGCB_VAL_UTF8((U8*) locinput,
6004                                                         (U8*) reginfo->strend));
6005                         }
6006                         break;
6007 
6008                     case LB_BOUND:
6009                         if (locinput == reginfo->strbeg) {
6010                             match = FALSE;
6011                         }
6012                         else if (NEXTCHR_IS_EOS) {
6013                             match = TRUE;
6014                         }
6015                         else {
6016                             match = isLB(getLB_VAL_UTF8(
6017                                                 reghop3((U8*)locinput,
6018                                                         -1,
6019                                                         (U8*)(reginfo->strbeg)),
6020                                                 (U8*) reginfo->strend),
6021                                           getLB_VAL_UTF8((U8*) locinput,
6022                                                         (U8*) reginfo->strend),
6023                                           (U8*) reginfo->strbeg,
6024                                           (U8*) locinput,
6025                                           (U8*) reginfo->strend,
6026                                           utf8_target);
6027                         }
6028                         break;
6029 
6030                     case SB_BOUND: /* Always matches at begin and end */
6031                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
6032                             match = TRUE;
6033                         }
6034                         else {
6035                             match = isSB(getSB_VAL_UTF8(
6036                                                 reghop3((U8*)locinput,
6037                                                         -1,
6038                                                         (U8*)(reginfo->strbeg)),
6039                                                 (U8*) reginfo->strend),
6040                                           getSB_VAL_UTF8((U8*) locinput,
6041                                                         (U8*) reginfo->strend),
6042                                           (U8*) reginfo->strbeg,
6043                                           (U8*) locinput,
6044                                           (U8*) reginfo->strend,
6045                                           utf8_target);
6046                         }
6047                         break;
6048 
6049                     case WB_BOUND:
6050                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
6051                             match = TRUE;
6052                         }
6053                         else {
6054                             match = isWB(WB_UNKNOWN,
6055                                          getWB_VAL_UTF8(
6056                                                 reghop3((U8*)locinput,
6057                                                         -1,
6058                                                         (U8*)(reginfo->strbeg)),
6059                                                 (U8*) reginfo->strend),
6060                                           getWB_VAL_UTF8((U8*) locinput,
6061                                                         (U8*) reginfo->strend),
6062                                           (U8*) reginfo->strbeg,
6063                                           (U8*) locinput,
6064                                           (U8*) reginfo->strend,
6065                                           utf8_target);
6066                         }
6067                         break;
6068                 }
6069 	    }
6070 	    else {  /* Not utf8 target */
6071                 switch((bound_type) FLAGS(scan)) {
6072                     case TRADITIONAL_BOUND:
6073                     {
6074                         bool b1, b2;
6075                         b1 = (locinput == reginfo->strbeg)
6076                             ? 0 /* isWORDCHAR_L1('\n') */
6077                             : isWORDCHAR_L1(UCHARAT(locinput - 1));
6078                         b2 = (NEXTCHR_IS_EOS)
6079                             ? 0 /* isWORDCHAR_L1('\n') */
6080                             : isWORDCHAR_L1(nextchr);
6081                         match = cBOOL(b1 != b2);
6082                         break;
6083                     }
6084 
6085                     case GCB_BOUND:
6086                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
6087                             match = TRUE; /* GCB always matches at begin and
6088                                              end */
6089                         }
6090                         else {  /* Only CR-LF combo isn't a GCB in 0-255
6091                                    range */
6092                             match =    UCHARAT(locinput - 1) != '\r'
6093                                     || UCHARAT(locinput) != '\n';
6094                         }
6095                         break;
6096 
6097                     case LB_BOUND:
6098                         if (locinput == reginfo->strbeg) {
6099                             match = FALSE;
6100                         }
6101                         else if (NEXTCHR_IS_EOS) {
6102                             match = TRUE;
6103                         }
6104                         else {
6105                             match = isLB(getLB_VAL_CP(UCHARAT(locinput -1)),
6106                                          getLB_VAL_CP(UCHARAT(locinput)),
6107                                          (U8*) reginfo->strbeg,
6108                                          (U8*) locinput,
6109                                          (U8*) reginfo->strend,
6110                                          utf8_target);
6111                         }
6112                         break;
6113 
6114                     case SB_BOUND: /* Always matches at begin and end */
6115                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
6116                             match = TRUE;
6117                         }
6118                         else {
6119                             match = isSB(getSB_VAL_CP(UCHARAT(locinput -1)),
6120                                          getSB_VAL_CP(UCHARAT(locinput)),
6121                                          (U8*) reginfo->strbeg,
6122                                          (U8*) locinput,
6123                                          (U8*) reginfo->strend,
6124                                          utf8_target);
6125                         }
6126                         break;
6127 
6128                     case WB_BOUND:
6129                         if (locinput == reginfo->strbeg || NEXTCHR_IS_EOS) {
6130                             match = TRUE;
6131                         }
6132                         else {
6133                             match = isWB(WB_UNKNOWN,
6134                                          getWB_VAL_CP(UCHARAT(locinput -1)),
6135                                          getWB_VAL_CP(UCHARAT(locinput)),
6136                                          (U8*) reginfo->strbeg,
6137                                          (U8*) locinput,
6138                                          (U8*) reginfo->strend,
6139                                          utf8_target);
6140                         }
6141                         break;
6142                 }
6143 	    }
6144 
6145             if (to_complement ^ ! match) {
6146                 sayNO;
6147             }
6148 	    break;
6149 
6150 	case ANYOFL:  /*  /[abc]/l      */
6151             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
6152 
6153             if (ANYOFL_UTF8_LOCALE_REQD(FLAGS(scan)) && ! IN_UTF8_CTYPE_LOCALE)
6154             {
6155               Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE), utf8_locale_required);
6156             }
6157             /* FALLTHROUGH */
6158 	case ANYOFD:  /*   /[abc]/d       */
6159 	case ANYOF:  /*   /[abc]/       */
6160             if (NEXTCHR_IS_EOS)
6161                 sayNO;
6162 	    if (utf8_target && ! UTF8_IS_INVARIANT(*locinput)) {
6163 	        if (!reginclass(rex, scan, (U8*)locinput, (U8*)reginfo->strend,
6164                                                                    utf8_target))
6165 		    sayNO;
6166 		locinput += UTF8SKIP(locinput);
6167 	    }
6168 	    else {
6169 		if (!REGINCLASS(rex, scan, (U8*)locinput, utf8_target))
6170 		    sayNO;
6171 		locinput++;
6172 	    }
6173 	    break;
6174 
6175         /* The argument (FLAGS) to all the POSIX node types is the class number
6176          * */
6177 
6178         case NPOSIXL:   /* \W or [:^punct:] etc. under /l */
6179             to_complement = 1;
6180             /* FALLTHROUGH */
6181 
6182         case POSIXL:    /* \w or [:punct:] etc. under /l */
6183             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
6184             if (NEXTCHR_IS_EOS)
6185                 sayNO;
6186 
6187             /* Use isFOO_lc() for characters within Latin1.  (Note that
6188              * UTF8_IS_INVARIANT works even on non-UTF-8 strings, or else
6189              * wouldn't be invariant) */
6190             if (UTF8_IS_INVARIANT(nextchr) || ! utf8_target) {
6191                 if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan), (U8) nextchr)))) {
6192                     sayNO;
6193                 }
6194             }
6195             else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
6196                 if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan),
6197                                                EIGHT_BIT_UTF8_TO_NATIVE(nextchr,
6198                                                *(locinput + 1))))))
6199                 {
6200                     sayNO;
6201                 }
6202             }
6203             else { /* Here, must be an above Latin-1 code point */
6204                 _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(locinput, reginfo->strend);
6205                 goto utf8_posix_above_latin1;
6206             }
6207 
6208             /* Here, must be utf8 */
6209             locinput += UTF8SKIP(locinput);
6210             break;
6211 
6212         case NPOSIXD:   /* \W or [:^punct:] etc. under /d */
6213             to_complement = 1;
6214             /* FALLTHROUGH */
6215 
6216         case POSIXD:    /* \w or [:punct:] etc. under /d */
6217             if (utf8_target) {
6218                 goto utf8_posix;
6219             }
6220             goto posixa;
6221 
6222         case NPOSIXA:   /* \W or [:^punct:] etc. under /a */
6223 
6224             if (NEXTCHR_IS_EOS) {
6225                 sayNO;
6226             }
6227 
6228             /* All UTF-8 variants match */
6229             if (! UTF8_IS_INVARIANT(nextchr)) {
6230                 goto increment_locinput;
6231             }
6232 
6233             to_complement = 1;
6234             goto join_nposixa;
6235 
6236         case POSIXA:    /* \w or [:punct:] etc. under /a */
6237 
6238           posixa:
6239             /* We get here through POSIXD, NPOSIXD, and NPOSIXA when not in
6240              * UTF-8, and also from NPOSIXA even in UTF-8 when the current
6241              * character is a single byte */
6242 
6243             if (NEXTCHR_IS_EOS) {
6244                 sayNO;
6245             }
6246 
6247           join_nposixa:
6248 
6249             if (! (to_complement ^ cBOOL(_generic_isCC_A(nextchr,
6250                                                                 FLAGS(scan)))))
6251             {
6252                 sayNO;
6253             }
6254 
6255             /* Here we are either not in utf8, or we matched a utf8-invariant,
6256              * so the next char is the next byte */
6257             locinput++;
6258             break;
6259 
6260         case NPOSIXU:   /* \W or [:^punct:] etc. under /u */
6261             to_complement = 1;
6262             /* FALLTHROUGH */
6263 
6264         case POSIXU:    /* \w or [:punct:] etc. under /u */
6265           utf8_posix:
6266             if (NEXTCHR_IS_EOS) {
6267                 sayNO;
6268             }
6269 
6270             /* Use _generic_isCC() for characters within Latin1.  (Note that
6271              * UTF8_IS_INVARIANT works even on non-UTF-8 strings, or else
6272              * wouldn't be invariant) */
6273             if (UTF8_IS_INVARIANT(nextchr) || ! utf8_target) {
6274                 if (! (to_complement ^ cBOOL(_generic_isCC(nextchr,
6275                                                            FLAGS(scan)))))
6276                 {
6277                     sayNO;
6278                 }
6279                 locinput++;
6280             }
6281             else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
6282                 if (! (to_complement
6283                        ^ cBOOL(_generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(nextchr,
6284                                                                *(locinput + 1)),
6285                                              FLAGS(scan)))))
6286                 {
6287                     sayNO;
6288                 }
6289                 locinput += 2;
6290             }
6291             else {  /* Handle above Latin-1 code points */
6292               utf8_posix_above_latin1:
6293                 classnum = (_char_class_number) FLAGS(scan);
6294                 if (classnum < _FIRST_NON_SWASH_CC) {
6295 
6296                     /* Here, uses a swash to find such code points.  Load if if
6297                      * not done already */
6298                     if (! PL_utf8_swash_ptrs[classnum]) {
6299                         U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
6300                         PL_utf8_swash_ptrs[classnum]
6301                                 = _core_swash_init("utf8",
6302                                         "",
6303                                         &PL_sv_undef, 1, 0,
6304                                         PL_XPosix_ptrs[classnum], &flags);
6305                     }
6306                     if (! (to_complement
6307                            ^ cBOOL(swash_fetch(PL_utf8_swash_ptrs[classnum],
6308                                                (U8 *) locinput, TRUE))))
6309                     {
6310                         sayNO;
6311                     }
6312                 }
6313                 else {  /* Here, uses macros to find above Latin-1 code points */
6314                     switch (classnum) {
6315                         case _CC_ENUM_SPACE:
6316                             if (! (to_complement
6317                                         ^ cBOOL(is_XPERLSPACE_high(locinput))))
6318                             {
6319                                 sayNO;
6320                             }
6321                             break;
6322                         case _CC_ENUM_BLANK:
6323                             if (! (to_complement
6324                                             ^ cBOOL(is_HORIZWS_high(locinput))))
6325                             {
6326                                 sayNO;
6327                             }
6328                             break;
6329                         case _CC_ENUM_XDIGIT:
6330                             if (! (to_complement
6331                                             ^ cBOOL(is_XDIGIT_high(locinput))))
6332                             {
6333                                 sayNO;
6334                             }
6335                             break;
6336                         case _CC_ENUM_VERTSPACE:
6337                             if (! (to_complement
6338                                             ^ cBOOL(is_VERTWS_high(locinput))))
6339                             {
6340                                 sayNO;
6341                             }
6342                             break;
6343                         default:    /* The rest, e.g. [:cntrl:], can't match
6344                                        above Latin1 */
6345                             if (! to_complement) {
6346                                 sayNO;
6347                             }
6348                             break;
6349                     }
6350                 }
6351                 locinput += UTF8SKIP(locinput);
6352             }
6353             break;
6354 
6355 	case CLUMP: /* Match \X: logical Unicode character.  This is defined as
6356 		       a Unicode extended Grapheme Cluster */
6357 	    if (NEXTCHR_IS_EOS)
6358 		sayNO;
6359 	    if  (! utf8_target) {
6360 
6361 		/* Match either CR LF  or '.', as all the other possibilities
6362 		 * require utf8 */
6363 		locinput++;	    /* Match the . or CR */
6364 		if (nextchr == '\r' /* And if it was CR, and the next is LF,
6365 				       match the LF */
6366 		    && locinput < reginfo->strend
6367 		    && UCHARAT(locinput) == '\n')
6368                 {
6369                     locinput++;
6370                 }
6371 	    }
6372 	    else {
6373 
6374                 /* Get the gcb type for the current character */
6375                 GCB_enum prev_gcb = getGCB_VAL_UTF8((U8*) locinput,
6376                                                        (U8*) reginfo->strend);
6377 
6378                 /* Then scan through the input until we get to the first
6379                  * character whose type is supposed to be a gcb with the
6380                  * current character.  (There is always a break at the
6381                  * end-of-input) */
6382                 locinput += UTF8SKIP(locinput);
6383                 while (locinput < reginfo->strend) {
6384                     GCB_enum cur_gcb = getGCB_VAL_UTF8((U8*) locinput,
6385                                                          (U8*) reginfo->strend);
6386                     if (isGCB(prev_gcb, cur_gcb)) {
6387                         break;
6388                     }
6389 
6390                     prev_gcb = cur_gcb;
6391                     locinput += UTF8SKIP(locinput);
6392                 }
6393 
6394 
6395 	    }
6396 	    break;
6397 
6398 	case NREFFL:  /*  /\g{name}/il  */
6399 	{   /* The capture buffer cases.  The ones beginning with N for the
6400 	       named buffers just convert to the equivalent numbered and
6401 	       pretend they were called as the corresponding numbered buffer
6402 	       op.  */
6403 	    /* don't initialize these in the declaration, it makes C++
6404 	       unhappy */
6405 	    const char *s;
6406 	    char type;
6407 	    re_fold_t folder;
6408 	    const U8 *fold_array;
6409 	    UV utf8_fold_flags;
6410 
6411             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
6412 	    folder = foldEQ_locale;
6413 	    fold_array = PL_fold_locale;
6414 	    type = REFFL;
6415 	    utf8_fold_flags = FOLDEQ_LOCALE;
6416 	    goto do_nref;
6417 
6418 	case NREFFA:  /*  /\g{name}/iaa  */
6419 	    folder = foldEQ_latin1;
6420 	    fold_array = PL_fold_latin1;
6421 	    type = REFFA;
6422 	    utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
6423 	    goto do_nref;
6424 
6425 	case NREFFU:  /*  /\g{name}/iu  */
6426 	    folder = foldEQ_latin1;
6427 	    fold_array = PL_fold_latin1;
6428 	    type = REFFU;
6429 	    utf8_fold_flags = 0;
6430 	    goto do_nref;
6431 
6432 	case NREFF:  /*  /\g{name}/i  */
6433 	    folder = foldEQ;
6434 	    fold_array = PL_fold;
6435 	    type = REFF;
6436 	    utf8_fold_flags = 0;
6437 	    goto do_nref;
6438 
6439 	case NREF:  /*  /\g{name}/   */
6440 	    type = REF;
6441 	    folder = NULL;
6442 	    fold_array = NULL;
6443 	    utf8_fold_flags = 0;
6444 	  do_nref:
6445 
6446 	    /* For the named back references, find the corresponding buffer
6447 	     * number */
6448 	    n = reg_check_named_buff_matched(rex,scan);
6449 
6450             if ( ! n ) {
6451                 sayNO;
6452 	    }
6453 	    goto do_nref_ref_common;
6454 
6455 	case REFFL:  /*  /\1/il  */
6456             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
6457 	    folder = foldEQ_locale;
6458 	    fold_array = PL_fold_locale;
6459 	    utf8_fold_flags = FOLDEQ_LOCALE;
6460 	    goto do_ref;
6461 
6462 	case REFFA:  /*  /\1/iaa  */
6463 	    folder = foldEQ_latin1;
6464 	    fold_array = PL_fold_latin1;
6465 	    utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
6466 	    goto do_ref;
6467 
6468 	case REFFU:  /*  /\1/iu  */
6469 	    folder = foldEQ_latin1;
6470 	    fold_array = PL_fold_latin1;
6471 	    utf8_fold_flags = 0;
6472 	    goto do_ref;
6473 
6474 	case REFF:  /*  /\1/i  */
6475 	    folder = foldEQ;
6476 	    fold_array = PL_fold;
6477 	    utf8_fold_flags = 0;
6478 	    goto do_ref;
6479 
6480         case REF:  /*  /\1/    */
6481 	    folder = NULL;
6482 	    fold_array = NULL;
6483 	    utf8_fold_flags = 0;
6484 
6485 	  do_ref:
6486 	    type = OP(scan);
6487 	    n = ARG(scan);  /* which paren pair */
6488 
6489 	  do_nref_ref_common:
6490 	    ln = rex->offs[n].start;
6491 	    reginfo->poscache_iter = reginfo->poscache_maxiter; /* Void cache */
6492 	    if (rex->lastparen < n || ln == -1)
6493 		sayNO;			/* Do not match unless seen CLOSEn. */
6494 	    if (ln == rex->offs[n].end)
6495 		break;
6496 
6497 	    s = reginfo->strbeg + ln;
6498 	    if (type != REF	/* REF can do byte comparison */
6499 		&& (utf8_target || type == REFFU || type == REFFL))
6500 	    {
6501 		char * limit = reginfo->strend;
6502 
6503 		/* This call case insensitively compares the entire buffer
6504 		    * at s, with the current input starting at locinput, but
6505                     * not going off the end given by reginfo->strend, and
6506                     * returns in <limit> upon success, how much of the
6507                     * current input was matched */
6508 		if (! foldEQ_utf8_flags(s, NULL, rex->offs[n].end - ln, utf8_target,
6509 				    locinput, &limit, 0, utf8_target, utf8_fold_flags))
6510 		{
6511 		    sayNO;
6512 		}
6513 		locinput = limit;
6514 		break;
6515 	    }
6516 
6517 	    /* Not utf8:  Inline the first character, for speed. */
6518 	    if (!NEXTCHR_IS_EOS &&
6519                 UCHARAT(s) != nextchr &&
6520 		(type == REF ||
6521 		 UCHARAT(s) != fold_array[nextchr]))
6522 		sayNO;
6523 	    ln = rex->offs[n].end - ln;
6524 	    if (locinput + ln > reginfo->strend)
6525 		sayNO;
6526 	    if (ln > 1 && (type == REF
6527 			   ? memNE(s, locinput, ln)
6528 			   : ! folder(s, locinput, ln)))
6529 		sayNO;
6530 	    locinput += ln;
6531 	    break;
6532 	}
6533 
6534 	case NOTHING: /* null op; e.g. the 'nothing' following
6535                        * the '*' in m{(a+|b)*}' */
6536 	    break;
6537 	case TAIL: /* placeholder while compiling (A|B|C) */
6538 	    break;
6539 
6540 #undef  ST
6541 #define ST st->u.eval
6542 #define CUR_EVAL cur_eval->u.eval
6543 
6544 	{
6545 	    SV *ret;
6546 	    REGEXP *re_sv;
6547             regexp *re;
6548             regexp_internal *rei;
6549             regnode *startpoint;
6550             U32 arg;
6551 
6552 	case GOSUB: /*    /(...(?1))/   /(...(?&foo))/   */
6553             arg= (U32)ARG(scan);
6554             if (cur_eval && cur_eval->locinput == locinput) {
6555                 if ( ++nochange_depth > max_nochange_depth )
6556                     Perl_croak(aTHX_
6557                         "Pattern subroutine nesting without pos change"
6558                         " exceeded limit in regex");
6559             } else {
6560                 nochange_depth = 0;
6561             }
6562 	    re_sv = rex_sv;
6563             re = rex;
6564             rei = rexi;
6565             startpoint = scan + ARG2L(scan);
6566             EVAL_CLOSE_PAREN_SET( st, arg );
6567             /* Detect infinite recursion
6568              *
6569              * A pattern like /(?R)foo/ or /(?<x>(?&y)foo)(?<y>(?&x)bar)/
6570              * or "a"=~/(.(?2))((?<=(?=(?1)).))/ could recurse forever.
6571              * So we track the position in the string we are at each time
6572              * we recurse and if we try to enter the same routine twice from
6573              * the same position we throw an error.
6574              */
6575             if ( rex->recurse_locinput[arg] == locinput ) {
6576                 /* FIXME: we should show the regop that is failing as part
6577                  * of the error message. */
6578                 Perl_croak(aTHX_ "Infinite recursion in regex");
6579             } else {
6580                 ST.prev_recurse_locinput= rex->recurse_locinput[arg];
6581                 rex->recurse_locinput[arg]= locinput;
6582 
6583                 DEBUG_r({
6584                     GET_RE_DEBUG_FLAGS_DECL;
6585                     DEBUG_STACK_r({
6586                         Perl_re_exec_indentf( aTHX_
6587                             "entering GOSUB, prev_recurse_locinput=%p recurse_locinput[%d]=%p\n",
6588                             depth, ST.prev_recurse_locinput, arg, rex->recurse_locinput[arg]
6589                         );
6590                     });
6591                 });
6592             }
6593 
6594             /* Save all the positions seen so far. */
6595             ST.cp = regcppush(rex, 0, maxopenparen);
6596             REGCP_SET(ST.lastcp);
6597 
6598             /* and then jump to the code we share with EVAL */
6599             goto eval_recurse_doit;
6600             /* NOTREACHED */
6601 
6602         case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */
6603             if (cur_eval && cur_eval->locinput==locinput) {
6604 		if ( ++nochange_depth > max_nochange_depth )
6605                     Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regex");
6606             } else {
6607                 nochange_depth = 0;
6608             }
6609 	    {
6610 		/* execute the code in the {...} */
6611 
6612 		dSP;
6613 		IV before;
6614 		OP * const oop = PL_op;
6615 		COP * const ocurcop = PL_curcop;
6616 		OP *nop;
6617 		CV *newcv;
6618 
6619 		/* save *all* paren positions */
6620 		regcppush(rex, 0, maxopenparen);
6621 		REGCP_SET(runops_cp);
6622 
6623 		if (!caller_cv)
6624 		    caller_cv = find_runcv(NULL);
6625 
6626 		n = ARG(scan);
6627 
6628 		if (rexi->data->what[n] == 'r') { /* code from an external qr */
6629                     newcv = (ReANY(
6630                                     (REGEXP*)(rexi->data->data[n])
6631                             ))->qr_anoncv;
6632 		    nop = (OP*)rexi->data->data[n+1];
6633 		}
6634 		else if (rexi->data->what[n] == 'l') { /* literal code */
6635 		    newcv = caller_cv;
6636 		    nop = (OP*)rexi->data->data[n];
6637 		    assert(CvDEPTH(newcv));
6638 		}
6639 		else {
6640 		    /* literal with own CV */
6641 		    assert(rexi->data->what[n] == 'L');
6642 		    newcv = rex->qr_anoncv;
6643 		    nop = (OP*)rexi->data->data[n];
6644 		}
6645 
6646 		/* normally if we're about to execute code from the same
6647 		 * CV that we used previously, we just use the existing
6648 		 * CX stack entry. However, its possible that in the
6649 		 * meantime we may have backtracked, popped from the save
6650 		 * stack, and undone the SAVECOMPPAD(s) associated with
6651 		 * PUSH_MULTICALL; in which case PL_comppad no longer
6652 		 * points to newcv's pad. */
6653 		if (newcv != last_pushed_cv || PL_comppad != last_pad)
6654 		{
6655                     U8 flags = (CXp_SUB_RE |
6656                                 ((newcv == caller_cv) ? CXp_SUB_RE_FAKE : 0));
6657 		    if (last_pushed_cv) {
6658                         /* PUSH/POP_MULTICALL save and restore the
6659                          * caller's PL_comppad; if we call multiple subs
6660                          * using the same CX block, we have to save and
6661                          * unwind the varying PL_comppad's ourselves,
6662                          * especially restoring the right PL_comppad on
6663                          * backtrack - so save it on the save stack */
6664                         SAVECOMPPAD();
6665 			CHANGE_MULTICALL_FLAGS(newcv, flags);
6666 		    }
6667 		    else {
6668 			PUSH_MULTICALL_FLAGS(newcv, flags);
6669 		    }
6670 		    last_pushed_cv = newcv;
6671 		}
6672 		else {
6673                     /* these assignments are just to silence compiler
6674                      * warnings */
6675 		    multicall_cop = NULL;
6676 		}
6677 		last_pad = PL_comppad;
6678 
6679 		/* the initial nextstate you would normally execute
6680 		 * at the start of an eval (which would cause error
6681 		 * messages to come from the eval), may be optimised
6682 		 * away from the execution path in the regex code blocks;
6683 		 * so manually set PL_curcop to it initially */
6684 		{
6685 		    OP *o = cUNOPx(nop)->op_first;
6686 		    assert(o->op_type == OP_NULL);
6687 		    if (o->op_targ == OP_SCOPE) {
6688 			o = cUNOPo->op_first;
6689 		    }
6690 		    else {
6691 			assert(o->op_targ == OP_LEAVE);
6692 			o = cUNOPo->op_first;
6693 			assert(o->op_type == OP_ENTER);
6694 			o = OpSIBLING(o);
6695 		    }
6696 
6697 		    if (o->op_type != OP_STUB) {
6698 			assert(    o->op_type == OP_NEXTSTATE
6699 				|| o->op_type == OP_DBSTATE
6700 				|| (o->op_type == OP_NULL
6701 				    &&  (  o->op_targ == OP_NEXTSTATE
6702 					|| o->op_targ == OP_DBSTATE
6703 					)
6704 				    )
6705 			);
6706 			PL_curcop = (COP*)o;
6707 		    }
6708 		}
6709 		nop = nop->op_next;
6710 
6711                 DEBUG_STATE_r( Perl_re_printf( aTHX_
6712 		    "  re EVAL PL_op=0x%"UVxf"\n", PTR2UV(nop)) );
6713 
6714 		rex->offs[0].end = locinput - reginfo->strbeg;
6715                 if (reginfo->info_aux_eval->pos_magic)
6716                     MgBYTEPOS_set(reginfo->info_aux_eval->pos_magic,
6717                                   reginfo->sv, reginfo->strbeg,
6718                                   locinput - reginfo->strbeg);
6719 
6720                 if (sv_yes_mark) {
6721                     SV *sv_mrk = get_sv("REGMARK", 1);
6722                     sv_setsv(sv_mrk, sv_yes_mark);
6723                 }
6724 
6725 		/* we don't use MULTICALL here as we want to call the
6726 		 * first op of the block of interest, rather than the
6727 		 * first op of the sub. Also, we don't want to free
6728                  * the savestack frame */
6729 		before = (IV)(SP-PL_stack_base);
6730 		PL_op = nop;
6731 		CALLRUNOPS(aTHX);			/* Scalar context. */
6732 		SPAGAIN;
6733 		if ((IV)(SP-PL_stack_base) == before)
6734 		    ret = &PL_sv_undef;   /* protect against empty (?{}) blocks. */
6735 		else {
6736 		    ret = POPs;
6737 		    PUTBACK;
6738 		}
6739 
6740 		/* before restoring everything, evaluate the returned
6741 		 * value, so that 'uninit' warnings don't use the wrong
6742 		 * PL_op or pad. Also need to process any magic vars
6743 		 * (e.g. $1) *before* parentheses are restored */
6744 
6745 		PL_op = NULL;
6746 
6747                 re_sv = NULL;
6748 		if (logical == 0)        /*   (?{})/   */
6749 		    sv_setsv(save_scalar(PL_replgv), ret); /* $^R */
6750 		else if (logical == 1) { /*   /(?(?{...})X|Y)/    */
6751 		    sw = cBOOL(SvTRUE(ret));
6752 		    logical = 0;
6753 		}
6754 		else {                   /*  /(??{})  */
6755 		    /*  if its overloaded, let the regex compiler handle
6756 		     *  it; otherwise extract regex, or stringify  */
6757 		    if (SvGMAGICAL(ret))
6758 			ret = sv_mortalcopy(ret);
6759 		    if (!SvAMAGIC(ret)) {
6760 			SV *sv = ret;
6761 			if (SvROK(sv))
6762 			    sv = SvRV(sv);
6763 			if (SvTYPE(sv) == SVt_REGEXP)
6764 			    re_sv = (REGEXP*) sv;
6765 			else if (SvSMAGICAL(ret)) {
6766 			    MAGIC *mg = mg_find(ret, PERL_MAGIC_qr);
6767 			    if (mg)
6768 				re_sv = (REGEXP *) mg->mg_obj;
6769 			}
6770 
6771 			/* force any undef warnings here */
6772 			if (!re_sv && !SvPOK(ret) && !SvNIOK(ret)) {
6773 			    ret = sv_mortalcopy(ret);
6774 			    (void) SvPV_force_nolen(ret);
6775 			}
6776 		    }
6777 
6778 		}
6779 
6780 		/* *** Note that at this point we don't restore
6781 		 * PL_comppad, (or pop the CxSUB) on the assumption it may
6782 		 * be used again soon. This is safe as long as nothing
6783 		 * in the regexp code uses the pad ! */
6784 		PL_op = oop;
6785 		PL_curcop = ocurcop;
6786 		S_regcp_restore(aTHX_ rex, runops_cp, &maxopenparen);
6787 		PL_curpm = PL_reg_curpm;
6788 
6789 		if (logical != 2)
6790 		    break;
6791 	    }
6792 
6793 		/* only /(??{})/  from now on */
6794 		logical = 0;
6795 		{
6796 		    /* extract RE object from returned value; compiling if
6797 		     * necessary */
6798 
6799 		    if (re_sv) {
6800 			re_sv = reg_temp_copy(NULL, re_sv);
6801 		    }
6802 		    else {
6803 			U32 pm_flags = 0;
6804 
6805 			if (SvUTF8(ret) && IN_BYTES) {
6806 			    /* In use 'bytes': make a copy of the octet
6807 			     * sequence, but without the flag on */
6808 			    STRLEN len;
6809 			    const char *const p = SvPV(ret, len);
6810 			    ret = newSVpvn_flags(p, len, SVs_TEMP);
6811 			}
6812 			if (rex->intflags & PREGf_USE_RE_EVAL)
6813 			    pm_flags |= PMf_USE_RE_EVAL;
6814 
6815 			/* if we got here, it should be an engine which
6816 			 * supports compiling code blocks and stuff */
6817 			assert(rex->engine && rex->engine->op_comp);
6818                         assert(!(scan->flags & ~RXf_PMf_COMPILETIME));
6819 			re_sv = rex->engine->op_comp(aTHX_ &ret, 1, NULL,
6820 				    rex->engine, NULL, NULL,
6821                                     /* copy /msixn etc to inner pattern */
6822                                     ARG2L(scan),
6823                                     pm_flags);
6824 
6825 			if (!(SvFLAGS(ret)
6826 			      & (SVs_TEMP | SVs_GMG | SVf_ROK))
6827 			 && (!SvPADTMP(ret) || SvREADONLY(ret))) {
6828 			    /* This isn't a first class regexp. Instead, it's
6829 			       caching a regexp onto an existing, Perl visible
6830 			       scalar.  */
6831 			    sv_magic(ret, MUTABLE_SV(re_sv), PERL_MAGIC_qr, 0, 0);
6832 			}
6833 		    }
6834 		    SAVEFREESV(re_sv);
6835 		    re = ReANY(re_sv);
6836 		}
6837                 RXp_MATCH_COPIED_off(re);
6838                 re->subbeg = rex->subbeg;
6839                 re->sublen = rex->sublen;
6840                 re->suboffset = rex->suboffset;
6841                 re->subcoffset = rex->subcoffset;
6842                 re->lastparen = 0;
6843                 re->lastcloseparen = 0;
6844 		rei = RXi_GET(re);
6845                 DEBUG_EXECUTE_r(
6846                     debug_start_match(re_sv, utf8_target, locinput,
6847                                     reginfo->strend, "Matching embedded");
6848 		);
6849 		startpoint = rei->program + 1;
6850                 EVAL_CLOSE_PAREN_CLEAR(st); /* ST.close_paren = 0;
6851                                              * close_paren only for GOSUB */
6852                 ST.prev_recurse_locinput= NULL; /* only used for GOSUB */
6853                 /* Save all the seen positions so far. */
6854                 ST.cp = regcppush(rex, 0, maxopenparen);
6855                 REGCP_SET(ST.lastcp);
6856                 /* and set maxopenparen to 0, since we are starting a "fresh" match */
6857                 maxopenparen = 0;
6858                 /* run the pattern returned from (??{...}) */
6859 
6860               eval_recurse_doit: /* Share code with GOSUB below this line
6861                             * At this point we expect the stack context to be
6862                             * set up correctly */
6863 
6864                 /* invalidate the S-L poscache. We're now executing a
6865                  * different set of WHILEM ops (and their associated
6866                  * indexes) against the same string, so the bits in the
6867                  * cache are meaningless. Setting maxiter to zero forces
6868                  * the cache to be invalidated and zeroed before reuse.
6869 		 * XXX This is too dramatic a measure. Ideally we should
6870                  * save the old cache and restore when running the outer
6871                  * pattern again */
6872 		reginfo->poscache_maxiter = 0;
6873 
6874                 /* the new regexp might have a different is_utf8_pat than we do */
6875                 is_utf8_pat = reginfo->is_utf8_pat = cBOOL(RX_UTF8(re_sv));
6876 
6877 		ST.prev_rex = rex_sv;
6878 		ST.prev_curlyx = cur_curlyx;
6879 		rex_sv = re_sv;
6880 		SET_reg_curpm(rex_sv);
6881 		rex = re;
6882 		rexi = rei;
6883 		cur_curlyx = NULL;
6884 		ST.B = next;
6885 		ST.prev_eval = cur_eval;
6886 		cur_eval = st;
6887 		/* now continue from first node in postoned RE */
6888 		PUSH_YES_STATE_GOTO(EVAL_AB, startpoint, locinput);
6889 		NOT_REACHED; /* NOTREACHED */
6890 	}
6891 
6892 	case EVAL_AB: /* cleanup after a successful (??{A})B */
6893             /* note: this is called twice; first after popping B, then A */
6894             DEBUG_STACK_r({
6895                 Perl_re_exec_indentf( aTHX_  "EVAL_AB cur_eval=%p prev_eval=%p\n",
6896                     depth, cur_eval, ST.prev_eval);
6897             });
6898 
6899 #define SET_RECURSE_LOCINPUT(STR,VAL)\
6900             if ( cur_eval && CUR_EVAL.close_paren ) {\
6901                 DEBUG_STACK_r({ \
6902                     Perl_re_exec_indentf( aTHX_  STR " GOSUB%d ce=%p recurse_locinput=%p\n",\
6903                         depth,    \
6904                         CUR_EVAL.close_paren - 1,\
6905                         cur_eval, \
6906                         VAL);     \
6907                 });               \
6908                 rex->recurse_locinput[CUR_EVAL.close_paren - 1] = VAL;\
6909             }
6910 
6911             SET_RECURSE_LOCINPUT("EVAL_AB[before]", CUR_EVAL.prev_recurse_locinput);
6912 
6913 	    rex_sv = ST.prev_rex;
6914             is_utf8_pat = reginfo->is_utf8_pat = cBOOL(RX_UTF8(rex_sv));
6915 	    SET_reg_curpm(rex_sv);
6916 	    rex = ReANY(rex_sv);
6917 	    rexi = RXi_GET(rex);
6918             {
6919                 /* preserve $^R across LEAVE's. See Bug 121070. */
6920                 SV *save_sv= GvSV(PL_replgv);
6921                 SvREFCNT_inc(save_sv);
6922                 regcpblow(ST.cp); /* LEAVE in disguise */
6923                 sv_setsv(GvSV(PL_replgv), save_sv);
6924                 SvREFCNT_dec(save_sv);
6925             }
6926 	    cur_eval = ST.prev_eval;
6927 	    cur_curlyx = ST.prev_curlyx;
6928 
6929 	    /* Invalidate cache. See "invalidate" comment above. */
6930 	    reginfo->poscache_maxiter = 0;
6931             if ( nochange_depth )
6932 	        nochange_depth--;
6933 
6934             SET_RECURSE_LOCINPUT("EVAL_AB[after]", cur_eval->locinput);
6935 	    sayYES;
6936 
6937 
6938 	case EVAL_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
6939 	    /* note: this is called twice; first after popping B, then A */
6940             DEBUG_STACK_r({
6941                 Perl_re_exec_indentf( aTHX_  "EVAL_AB_fail cur_eval=%p prev_eval=%p\n",
6942                     depth, cur_eval, ST.prev_eval);
6943             });
6944 
6945             SET_RECURSE_LOCINPUT("EVAL_AB_fail[before]", CUR_EVAL.prev_recurse_locinput);
6946 
6947 	    rex_sv = ST.prev_rex;
6948             is_utf8_pat = reginfo->is_utf8_pat = cBOOL(RX_UTF8(rex_sv));
6949 	    SET_reg_curpm(rex_sv);
6950 	    rex = ReANY(rex_sv);
6951 	    rexi = RXi_GET(rex);
6952 
6953 	    REGCP_UNWIND(ST.lastcp);
6954 	    regcppop(rex, &maxopenparen);
6955 	    cur_eval = ST.prev_eval;
6956 	    cur_curlyx = ST.prev_curlyx;
6957 
6958 	    /* Invalidate cache. See "invalidate" comment above. */
6959 	    reginfo->poscache_maxiter = 0;
6960 	    if ( nochange_depth )
6961 	        nochange_depth--;
6962 
6963             SET_RECURSE_LOCINPUT("EVAL_AB_fail[after]", cur_eval->locinput);
6964             sayNO_SILENT;
6965 #undef ST
6966 
6967 	case OPEN: /*  (  */
6968 	    n = ARG(scan);  /* which paren pair */
6969 	    rex->offs[n].start_tmp = locinput - reginfo->strbeg;
6970 	    if (n > maxopenparen)
6971 		maxopenparen = n;
6972             DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
6973 		"rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf" tmp; maxopenparen=%"UVuf"\n",
6974 		PTR2UV(rex),
6975 		PTR2UV(rex->offs),
6976 		(UV)n,
6977 		(IV)rex->offs[n].start_tmp,
6978 		(UV)maxopenparen
6979 	    ));
6980             lastopen = n;
6981 	    break;
6982 
6983 /* XXX really need to log other places start/end are set too */
6984 #define CLOSE_CAPTURE                                                      \
6985     rex->offs[n].start = rex->offs[n].start_tmp;                           \
6986     rex->offs[n].end = locinput - reginfo->strbeg;                         \
6987     DEBUG_BUFFERS_r(Perl_re_printf( aTHX_                                              \
6988         "rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf"..%"IVdf"\n", \
6989         PTR2UV(rex),                                                       \
6990         PTR2UV(rex->offs),                                                 \
6991         (UV)n,                                                             \
6992         (IV)rex->offs[n].start,                                            \
6993         (IV)rex->offs[n].end                                               \
6994     ))
6995 
6996 	case CLOSE:  /*  )  */
6997 	    n = ARG(scan);  /* which paren pair */
6998 	    CLOSE_CAPTURE;
6999 	    if (n > rex->lastparen)
7000 		rex->lastparen = n;
7001 	    rex->lastcloseparen = n;
7002             if ( EVAL_CLOSE_PAREN_IS( cur_eval, n ) )
7003 	        goto fake_end;
7004 
7005 	    break;
7006 
7007         case ACCEPT:  /*  (*ACCEPT)  */
7008             if (scan->flags)
7009                 sv_yes_mark = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
7010             if (ARG2L(scan)){
7011                 regnode *cursor;
7012                 for (cursor=scan;
7013                      cursor && OP(cursor)!=END;
7014                      cursor=regnext(cursor))
7015                 {
7016                     if ( OP(cursor)==CLOSE ){
7017                         n = ARG(cursor);
7018                         if ( n <= lastopen ) {
7019 			    CLOSE_CAPTURE;
7020                             if (n > rex->lastparen)
7021                                 rex->lastparen = n;
7022                             rex->lastcloseparen = n;
7023                             if ( n == ARG(scan) || EVAL_CLOSE_PAREN_IS(cur_eval, n) )
7024                                 break;
7025                         }
7026                     }
7027                 }
7028             }
7029 	    goto fake_end;
7030 	    /* NOTREACHED */
7031 
7032 	case GROUPP:  /*  (?(1))  */
7033 	    n = ARG(scan);  /* which paren pair */
7034 	    sw = cBOOL(rex->lastparen >= n && rex->offs[n].end != -1);
7035 	    break;
7036 
7037 	case NGROUPP:  /*  (?(<name>))  */
7038 	    /* reg_check_named_buff_matched returns 0 for no match */
7039 	    sw = cBOOL(0 < reg_check_named_buff_matched(rex,scan));
7040 	    break;
7041 
7042         case INSUBP:   /*  (?(R))  */
7043             n = ARG(scan);
7044             /* this does not need to use EVAL_CLOSE_PAREN macros, as the arg
7045              * of SCAN is already set up as matches a eval.close_paren */
7046             sw = cur_eval && (n == 0 || CUR_EVAL.close_paren == n);
7047             break;
7048 
7049         case DEFINEP:  /*  (?(DEFINE))  */
7050             sw = 0;
7051             break;
7052 
7053 	case IFTHEN:   /*  (?(cond)A|B)  */
7054 	    reginfo->poscache_iter = reginfo->poscache_maxiter; /* Void cache */
7055 	    if (sw)
7056 		next = NEXTOPER(NEXTOPER(scan));
7057 	    else {
7058 		next = scan + ARG(scan);
7059 		if (OP(next) == IFTHEN) /* Fake one. */
7060 		    next = NEXTOPER(NEXTOPER(next));
7061 	    }
7062 	    break;
7063 
7064 	case LOGICAL:  /* modifier for EVAL and IFMATCH */
7065 	    logical = scan->flags;
7066 	    break;
7067 
7068 /*******************************************************************
7069 
7070 The CURLYX/WHILEM pair of ops handle the most generic case of the /A*B/
7071 pattern, where A and B are subpatterns. (For simple A, CURLYM or
7072 STAR/PLUS/CURLY/CURLYN are used instead.)
7073 
7074 A*B is compiled as <CURLYX><A><WHILEM><B>
7075 
7076 On entry to the subpattern, CURLYX is called. This pushes a CURLYX
7077 state, which contains the current count, initialised to -1. It also sets
7078 cur_curlyx to point to this state, with any previous value saved in the
7079 state block.
7080 
7081 CURLYX then jumps straight to the WHILEM op, rather than executing A,
7082 since the pattern may possibly match zero times (i.e. it's a while {} loop
7083 rather than a do {} while loop).
7084 
7085 Each entry to WHILEM represents a successful match of A. The count in the
7086 CURLYX block is incremented, another WHILEM state is pushed, and execution
7087 passes to A or B depending on greediness and the current count.
7088 
7089 For example, if matching against the string a1a2a3b (where the aN are
7090 substrings that match /A/), then the match progresses as follows: (the
7091 pushed states are interspersed with the bits of strings matched so far):
7092 
7093     <CURLYX cnt=-1>
7094     <CURLYX cnt=0><WHILEM>
7095     <CURLYX cnt=1><WHILEM> a1 <WHILEM>
7096     <CURLYX cnt=2><WHILEM> a1 <WHILEM> a2 <WHILEM>
7097     <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM>
7098     <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM> b
7099 
7100 (Contrast this with something like CURLYM, which maintains only a single
7101 backtrack state:
7102 
7103     <CURLYM cnt=0> a1
7104     a1 <CURLYM cnt=1> a2
7105     a1 a2 <CURLYM cnt=2> a3
7106     a1 a2 a3 <CURLYM cnt=3> b
7107 )
7108 
7109 Each WHILEM state block marks a point to backtrack to upon partial failure
7110 of A or B, and also contains some minor state data related to that
7111 iteration.  The CURLYX block, pointed to by cur_curlyx, contains the
7112 overall state, such as the count, and pointers to the A and B ops.
7113 
7114 This is complicated slightly by nested CURLYX/WHILEM's. Since cur_curlyx
7115 must always point to the *current* CURLYX block, the rules are:
7116 
7117 When executing CURLYX, save the old cur_curlyx in the CURLYX state block,
7118 and set cur_curlyx to point the new block.
7119 
7120 When popping the CURLYX block after a successful or unsuccessful match,
7121 restore the previous cur_curlyx.
7122 
7123 When WHILEM is about to execute B, save the current cur_curlyx, and set it
7124 to the outer one saved in the CURLYX block.
7125 
7126 When popping the WHILEM block after a successful or unsuccessful B match,
7127 restore the previous cur_curlyx.
7128 
7129 Here's an example for the pattern (AI* BI)*BO
7130 I and O refer to inner and outer, C and W refer to CURLYX and WHILEM:
7131 
7132 cur_
7133 curlyx backtrack stack
7134 ------ ---------------
7135 NULL
7136 CO     <CO prev=NULL> <WO>
7137 CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai
7138 CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi
7139 NULL   <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi <WO prev=CO> bo
7140 
7141 At this point the pattern succeeds, and we work back down the stack to
7142 clean up, restoring as we go:
7143 
7144 CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi
7145 CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai
7146 CO     <CO prev=NULL> <WO>
7147 NULL
7148 
7149 *******************************************************************/
7150 
7151 #define ST st->u.curlyx
7152 
7153 	case CURLYX:    /* start of /A*B/  (for complex A) */
7154 	{
7155 	    /* No need to save/restore up to this paren */
7156 	    I32 parenfloor = scan->flags;
7157 
7158 	    assert(next); /* keep Coverity happy */
7159 	    if (OP(PREVOPER(next)) == NOTHING) /* LONGJMP */
7160 		next += ARG(next);
7161 
7162 	    /* XXXX Probably it is better to teach regpush to support
7163 	       parenfloor > maxopenparen ... */
7164 	    if (parenfloor > (I32)rex->lastparen)
7165 		parenfloor = rex->lastparen; /* Pessimization... */
7166 
7167 	    ST.prev_curlyx= cur_curlyx;
7168 	    cur_curlyx = st;
7169 	    ST.cp = PL_savestack_ix;
7170 
7171 	    /* these fields contain the state of the current curly.
7172 	     * they are accessed by subsequent WHILEMs */
7173 	    ST.parenfloor = parenfloor;
7174 	    ST.me = scan;
7175 	    ST.B = next;
7176 	    ST.minmod = minmod;
7177 	    minmod = 0;
7178 	    ST.count = -1;	/* this will be updated by WHILEM */
7179 	    ST.lastloc = NULL;  /* this will be updated by WHILEM */
7180 
7181 	    PUSH_YES_STATE_GOTO(CURLYX_end, PREVOPER(next), locinput);
7182 	    NOT_REACHED; /* NOTREACHED */
7183 	}
7184 
7185 	case CURLYX_end: /* just finished matching all of A*B */
7186 	    cur_curlyx = ST.prev_curlyx;
7187 	    sayYES;
7188 	    NOT_REACHED; /* NOTREACHED */
7189 
7190 	case CURLYX_end_fail: /* just failed to match all of A*B */
7191 	    regcpblow(ST.cp);
7192 	    cur_curlyx = ST.prev_curlyx;
7193 	    sayNO;
7194 	    NOT_REACHED; /* NOTREACHED */
7195 
7196 
7197 #undef ST
7198 #define ST st->u.whilem
7199 
7200 	case WHILEM:     /* just matched an A in /A*B/  (for complex A) */
7201 	{
7202 	    /* see the discussion above about CURLYX/WHILEM */
7203 	    I32 n;
7204 	    int min, max;
7205 	    regnode *A;
7206 
7207 	    assert(cur_curlyx); /* keep Coverity happy */
7208 
7209 	    min = ARG1(cur_curlyx->u.curlyx.me);
7210 	    max = ARG2(cur_curlyx->u.curlyx.me);
7211 	    A = NEXTOPER(cur_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS;
7212 	    n = ++cur_curlyx->u.curlyx.count; /* how many A's matched */
7213 	    ST.save_lastloc = cur_curlyx->u.curlyx.lastloc;
7214 	    ST.cache_offset = 0;
7215 	    ST.cache_mask = 0;
7216 
7217 
7218             DEBUG_EXECUTE_r( Perl_re_exec_indentf( aTHX_  "whilem: matched %ld out of %d..%d\n",
7219                   depth, (long)n, min, max)
7220 	    );
7221 
7222 	    /* First just match a string of min A's. */
7223 
7224 	    if (n < min) {
7225 		ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
7226                                     maxopenparen);
7227 		cur_curlyx->u.curlyx.lastloc = locinput;
7228 		REGCP_SET(ST.lastcp);
7229 
7230 		PUSH_STATE_GOTO(WHILEM_A_pre, A, locinput);
7231 		NOT_REACHED; /* NOTREACHED */
7232 	    }
7233 
7234 	    /* If degenerate A matches "", assume A done. */
7235 
7236 	    if (locinput == cur_curlyx->u.curlyx.lastloc) {
7237                 DEBUG_EXECUTE_r( Perl_re_exec_indentf( aTHX_  "whilem: empty match detected, trying continuation...\n",
7238                    depth)
7239 		);
7240 		goto do_whilem_B_max;
7241 	    }
7242 
7243 	    /* super-linear cache processing.
7244              *
7245              * The idea here is that for certain types of CURLYX/WHILEM -
7246              * principally those whose upper bound is infinity (and
7247              * excluding regexes that have things like \1 and other very
7248              * non-regular expresssiony things), then if a pattern like
7249              * /....A*.../ fails and we backtrack to the WHILEM, then we
7250              * make a note that this particular WHILEM op was at string
7251              * position 47 (say) when the rest of pattern failed. Then, if
7252              * we ever find ourselves back at that WHILEM, and at string
7253              * position 47 again, we can just fail immediately rather than
7254              * running the rest of the pattern again.
7255              *
7256              * This is very handy when patterns start to go
7257              * 'super-linear', like in (a+)*(a+)*(a+)*, where you end up
7258              * with a combinatorial explosion of backtracking.
7259              *
7260              * The cache is implemented as a bit array, with one bit per
7261              * string byte position per WHILEM op (up to 16) - so its
7262              * between 0.25 and 2x the string size.
7263              *
7264              * To avoid allocating a poscache buffer every time, we do an
7265              * initially countdown; only after we have  executed a WHILEM
7266              * op (string-length x #WHILEMs) times do we allocate the
7267              * cache.
7268              *
7269              * The top 4 bits of scan->flags byte say how many different
7270              * relevant CURLLYX/WHILEM op pairs there are, while the
7271              * bottom 4-bits is the identifying index number of this
7272              * WHILEM.
7273              */
7274 
7275 	    if (scan->flags) {
7276 
7277 		if (!reginfo->poscache_maxiter) {
7278 		    /* start the countdown: Postpone detection until we
7279 		     * know the match is not *that* much linear. */
7280 		    reginfo->poscache_maxiter
7281                         =    (reginfo->strend - reginfo->strbeg + 1)
7282                            * (scan->flags>>4);
7283 		    /* possible overflow for long strings and many CURLYX's */
7284 		    if (reginfo->poscache_maxiter < 0)
7285 			reginfo->poscache_maxiter = I32_MAX;
7286 		    reginfo->poscache_iter = reginfo->poscache_maxiter;
7287 		}
7288 
7289 		if (reginfo->poscache_iter-- == 0) {
7290 		    /* initialise cache */
7291 		    const SSize_t size = (reginfo->poscache_maxiter + 7)/8;
7292                     regmatch_info_aux *const aux = reginfo->info_aux;
7293 		    if (aux->poscache) {
7294 			if ((SSize_t)reginfo->poscache_size < size) {
7295 			    Renew(aux->poscache, size, char);
7296 			    reginfo->poscache_size = size;
7297 			}
7298 			Zero(aux->poscache, size, char);
7299 		    }
7300 		    else {
7301 			reginfo->poscache_size = size;
7302 			Newxz(aux->poscache, size, char);
7303 		    }
7304                     DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
7305       "%swhilem: Detected a super-linear match, switching on caching%s...\n",
7306 			      PL_colors[4], PL_colors[5])
7307 		    );
7308 		}
7309 
7310 		if (reginfo->poscache_iter < 0) {
7311 		    /* have we already failed at this position? */
7312 		    SSize_t offset, mask;
7313 
7314                     reginfo->poscache_iter = -1; /* stop eventual underflow */
7315 		    offset  = (scan->flags & 0xf) - 1
7316                                 +   (locinput - reginfo->strbeg)
7317                                   * (scan->flags>>4);
7318 		    mask    = 1 << (offset % 8);
7319 		    offset /= 8;
7320 		    if (reginfo->info_aux->poscache[offset] & mask) {
7321                         DEBUG_EXECUTE_r( Perl_re_exec_indentf( aTHX_  "whilem: (cache) already tried at this position...\n",
7322                             depth)
7323 			);
7324 			sayNO; /* cache records failure */
7325 		    }
7326 		    ST.cache_offset = offset;
7327 		    ST.cache_mask   = mask;
7328 		}
7329 	    }
7330 
7331 	    /* Prefer B over A for minimal matching. */
7332 
7333 	    if (cur_curlyx->u.curlyx.minmod) {
7334 		ST.save_curlyx = cur_curlyx;
7335 		cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
7336 		ST.cp = regcppush(rex, ST.save_curlyx->u.curlyx.parenfloor,
7337                             maxopenparen);
7338 		REGCP_SET(ST.lastcp);
7339 		PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B,
7340                                     locinput);
7341 		NOT_REACHED; /* NOTREACHED */
7342 	    }
7343 
7344 	    /* Prefer A over B for maximal matching. */
7345 
7346 	    if (n < max) { /* More greed allowed? */
7347 		ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
7348                             maxopenparen);
7349 		cur_curlyx->u.curlyx.lastloc = locinput;
7350 		REGCP_SET(ST.lastcp);
7351 		PUSH_STATE_GOTO(WHILEM_A_max, A, locinput);
7352 		NOT_REACHED; /* NOTREACHED */
7353 	    }
7354 	    goto do_whilem_B_max;
7355 	}
7356 	NOT_REACHED; /* NOTREACHED */
7357 
7358 	case WHILEM_B_min: /* just matched B in a minimal match */
7359 	case WHILEM_B_max: /* just matched B in a maximal match */
7360 	    cur_curlyx = ST.save_curlyx;
7361 	    sayYES;
7362 	    NOT_REACHED; /* NOTREACHED */
7363 
7364 	case WHILEM_B_max_fail: /* just failed to match B in a maximal match */
7365 	    cur_curlyx = ST.save_curlyx;
7366 	    cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
7367 	    cur_curlyx->u.curlyx.count--;
7368 	    CACHEsayNO;
7369 	    NOT_REACHED; /* NOTREACHED */
7370 
7371 	case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
7372 	    /* FALLTHROUGH */
7373 	case WHILEM_A_pre_fail: /* just failed to match even minimal A */
7374 	    REGCP_UNWIND(ST.lastcp);
7375 	    regcppop(rex, &maxopenparen);
7376 	    cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
7377 	    cur_curlyx->u.curlyx.count--;
7378 	    CACHEsayNO;
7379 	    NOT_REACHED; /* NOTREACHED */
7380 
7381 	case WHILEM_A_max_fail: /* just failed to match A in a maximal match */
7382 	    REGCP_UNWIND(ST.lastcp);
7383 	    regcppop(rex, &maxopenparen); /* Restore some previous $<digit>s? */
7384             DEBUG_EXECUTE_r(Perl_re_exec_indentf( aTHX_  "whilem: failed, trying continuation...\n",
7385                 depth)
7386 	    );
7387 	  do_whilem_B_max:
7388 	    if (cur_curlyx->u.curlyx.count >= REG_INFTY
7389 		&& ckWARN(WARN_REGEXP)
7390 		&& !reginfo->warned)
7391 	    {
7392                 reginfo->warned	= TRUE;
7393 		Perl_warner(aTHX_ packWARN(WARN_REGEXP),
7394 		     "Complex regular subexpression recursion limit (%d) "
7395 		     "exceeded",
7396 		     REG_INFTY - 1);
7397 	    }
7398 
7399 	    /* now try B */
7400 	    ST.save_curlyx = cur_curlyx;
7401 	    cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
7402 	    PUSH_YES_STATE_GOTO(WHILEM_B_max, ST.save_curlyx->u.curlyx.B,
7403                                 locinput);
7404 	    NOT_REACHED; /* NOTREACHED */
7405 
7406 	case WHILEM_B_min_fail: /* just failed to match B in a minimal match */
7407 	    cur_curlyx = ST.save_curlyx;
7408 	    REGCP_UNWIND(ST.lastcp);
7409 	    regcppop(rex, &maxopenparen);
7410 
7411 	    if (cur_curlyx->u.curlyx.count >= /*max*/ARG2(cur_curlyx->u.curlyx.me)) {
7412 		/* Maximum greed exceeded */
7413 		if (cur_curlyx->u.curlyx.count >= REG_INFTY
7414 		    && ckWARN(WARN_REGEXP)
7415                     && !reginfo->warned)
7416 		{
7417                     reginfo->warned	= TRUE;
7418 		    Perl_warner(aTHX_ packWARN(WARN_REGEXP),
7419 			"Complex regular subexpression recursion "
7420 			"limit (%d) exceeded",
7421 			REG_INFTY - 1);
7422 		}
7423 		cur_curlyx->u.curlyx.count--;
7424 		CACHEsayNO;
7425 	    }
7426 
7427             DEBUG_EXECUTE_r(Perl_re_exec_indentf( aTHX_  "trying longer...\n", depth)
7428 	    );
7429 	    /* Try grabbing another A and see if it helps. */
7430 	    cur_curlyx->u.curlyx.lastloc = locinput;
7431 	    ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
7432                             maxopenparen);
7433 	    REGCP_SET(ST.lastcp);
7434 	    PUSH_STATE_GOTO(WHILEM_A_min,
7435 		/*A*/ NEXTOPER(ST.save_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS,
7436                 locinput);
7437 	    NOT_REACHED; /* NOTREACHED */
7438 
7439 #undef  ST
7440 #define ST st->u.branch
7441 
7442 	case BRANCHJ:	    /*  /(...|A|...)/ with long next pointer */
7443 	    next = scan + ARG(scan);
7444 	    if (next == scan)
7445 		next = NULL;
7446 	    scan = NEXTOPER(scan);
7447 	    /* FALLTHROUGH */
7448 
7449 	case BRANCH:	    /*  /(...|A|...)/ */
7450 	    scan = NEXTOPER(scan); /* scan now points to inner node */
7451 	    ST.lastparen = rex->lastparen;
7452 	    ST.lastcloseparen = rex->lastcloseparen;
7453 	    ST.next_branch = next;
7454 	    REGCP_SET(ST.cp);
7455 
7456 	    /* Now go into the branch */
7457 	    if (has_cutgroup) {
7458 	        PUSH_YES_STATE_GOTO(BRANCH_next, scan, locinput);
7459 	    } else {
7460 	        PUSH_STATE_GOTO(BRANCH_next, scan, locinput);
7461 	    }
7462 	    NOT_REACHED; /* NOTREACHED */
7463 
7464         case CUTGROUP:  /*  /(*THEN)/  */
7465             sv_yes_mark = st->u.mark.mark_name = scan->flags
7466                 ? MUTABLE_SV(rexi->data->data[ ARG( scan ) ])
7467                 : NULL;
7468             PUSH_STATE_GOTO(CUTGROUP_next, next, locinput);
7469             NOT_REACHED; /* NOTREACHED */
7470 
7471         case CUTGROUP_next_fail:
7472             do_cutgroup = 1;
7473             no_final = 1;
7474             if (st->u.mark.mark_name)
7475                 sv_commit = st->u.mark.mark_name;
7476             sayNO;
7477             NOT_REACHED; /* NOTREACHED */
7478 
7479         case BRANCH_next:
7480             sayYES;
7481             NOT_REACHED; /* NOTREACHED */
7482 
7483 	case BRANCH_next_fail: /* that branch failed; try the next, if any */
7484 	    if (do_cutgroup) {
7485 	        do_cutgroup = 0;
7486 	        no_final = 0;
7487 	    }
7488 	    REGCP_UNWIND(ST.cp);
7489             UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
7490 	    scan = ST.next_branch;
7491 	    /* no more branches? */
7492 	    if (!scan || (OP(scan) != BRANCH && OP(scan) != BRANCHJ)) {
7493 	        DEBUG_EXECUTE_r({
7494                     Perl_re_exec_indentf( aTHX_  "%sBRANCH failed...%s\n",
7495                         depth,
7496 			PL_colors[4],
7497 			PL_colors[5] );
7498 		});
7499 		sayNO_SILENT;
7500             }
7501 	    continue; /* execute next BRANCH[J] op */
7502             /* NOTREACHED */
7503 
7504 	case MINMOD: /* next op will be non-greedy, e.g. A*?  */
7505 	    minmod = 1;
7506 	    break;
7507 
7508 #undef  ST
7509 #define ST st->u.curlym
7510 
7511 	case CURLYM:	/* /A{m,n}B/ where A is fixed-length */
7512 
7513 	    /* This is an optimisation of CURLYX that enables us to push
7514 	     * only a single backtracking state, no matter how many matches
7515 	     * there are in {m,n}. It relies on the pattern being constant
7516 	     * length, with no parens to influence future backrefs
7517 	     */
7518 
7519 	    ST.me = scan;
7520 	    scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
7521 
7522 	    ST.lastparen      = rex->lastparen;
7523 	    ST.lastcloseparen = rex->lastcloseparen;
7524 
7525 	    /* if paren positive, emulate an OPEN/CLOSE around A */
7526 	    if (ST.me->flags) {
7527 		U32 paren = ST.me->flags;
7528 		if (paren > maxopenparen)
7529 		    maxopenparen = paren;
7530 		scan += NEXT_OFF(scan); /* Skip former OPEN. */
7531 	    }
7532 	    ST.A = scan;
7533 	    ST.B = next;
7534 	    ST.alen = 0;
7535 	    ST.count = 0;
7536 	    ST.minmod = minmod;
7537 	    minmod = 0;
7538 	    ST.c1 = CHRTEST_UNINIT;
7539 	    REGCP_SET(ST.cp);
7540 
7541 	    if (!(ST.minmod ? ARG1(ST.me) : ARG2(ST.me))) /* min/max */
7542 		goto curlym_do_B;
7543 
7544 	  curlym_do_A: /* execute the A in /A{m,n}B/  */
7545 	    PUSH_YES_STATE_GOTO(CURLYM_A, ST.A, locinput); /* match A */
7546 	    NOT_REACHED; /* NOTREACHED */
7547 
7548 	case CURLYM_A: /* we've just matched an A */
7549 	    ST.count++;
7550 	    /* after first match, determine A's length: u.curlym.alen */
7551 	    if (ST.count == 1) {
7552 		if (reginfo->is_utf8_target) {
7553 		    char *s = st->locinput;
7554 		    while (s < locinput) {
7555 			ST.alen++;
7556 			s += UTF8SKIP(s);
7557 		    }
7558 		}
7559 		else {
7560 		    ST.alen = locinput - st->locinput;
7561 		}
7562 		if (ST.alen == 0)
7563 		    ST.count = ST.minmod ? ARG1(ST.me) : ARG2(ST.me);
7564 	    }
7565 	    DEBUG_EXECUTE_r(
7566                 Perl_re_exec_indentf( aTHX_  "CURLYM now matched %"IVdf" times, len=%"IVdf"...\n",
7567                           depth, (IV) ST.count, (IV)ST.alen)
7568 	    );
7569 
7570             if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
7571 	        goto fake_end;
7572 
7573 	    {
7574 		I32 max = (ST.minmod ? ARG1(ST.me) : ARG2(ST.me));
7575 		if ( max == REG_INFTY || ST.count < max )
7576 		    goto curlym_do_A; /* try to match another A */
7577 	    }
7578 	    goto curlym_do_B; /* try to match B */
7579 
7580 	case CURLYM_A_fail: /* just failed to match an A */
7581 	    REGCP_UNWIND(ST.cp);
7582 
7583 
7584 	    if (ST.minmod || ST.count < ARG1(ST.me) /* min*/
7585                 || EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
7586 		sayNO;
7587 
7588 	  curlym_do_B: /* execute the B in /A{m,n}B/  */
7589 	    if (ST.c1 == CHRTEST_UNINIT) {
7590 		/* calculate c1 and c2 for possible match of 1st char
7591 		 * following curly */
7592 		ST.c1 = ST.c2 = CHRTEST_VOID;
7593                 assert(ST.B);
7594 		if (HAS_TEXT(ST.B) || JUMPABLE(ST.B)) {
7595 		    regnode *text_node = ST.B;
7596 		    if (! HAS_TEXT(text_node))
7597 			FIND_NEXT_IMPT(text_node);
7598 	            /* this used to be
7599 
7600 	                (HAS_TEXT(text_node) && PL_regkind[OP(text_node)] == EXACT)
7601 
7602 	            	But the former is redundant in light of the latter.
7603 
7604 	            	if this changes back then the macro for
7605 	            	IS_TEXT and friends need to change.
7606 	             */
7607 		    if (PL_regkind[OP(text_node)] == EXACT) {
7608                         if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
7609                            text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8,
7610                            reginfo))
7611                         {
7612                             sayNO;
7613                         }
7614 		    }
7615 		}
7616 	    }
7617 
7618 	    DEBUG_EXECUTE_r(
7619                 Perl_re_exec_indentf( aTHX_  "CURLYM trying tail with matches=%"IVdf"...\n",
7620                     depth, (IV)ST.count)
7621 		);
7622 	    if (! NEXTCHR_IS_EOS && ST.c1 != CHRTEST_VOID) {
7623                 if (! UTF8_IS_INVARIANT(nextchr) && utf8_target) {
7624                     if (memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
7625                         && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
7626                     {
7627                         /* simulate B failing */
7628                         DEBUG_OPTIMISE_r(
7629                             Perl_re_exec_indentf( aTHX_  "CURLYM Fast bail next target=0x%"UVXf" c1=0x%"UVXf" c2=0x%"UVXf"\n",
7630                                 depth,
7631                                 valid_utf8_to_uvchr((U8 *) locinput, NULL),
7632                                 valid_utf8_to_uvchr(ST.c1_utf8, NULL),
7633                                 valid_utf8_to_uvchr(ST.c2_utf8, NULL))
7634                         );
7635                         state_num = CURLYM_B_fail;
7636                         goto reenter_switch;
7637                     }
7638                 }
7639                 else if (nextchr != ST.c1 && nextchr != ST.c2) {
7640                     /* simulate B failing */
7641                     DEBUG_OPTIMISE_r(
7642                         Perl_re_exec_indentf( aTHX_  "CURLYM Fast bail next target=0x%X c1=0x%X c2=0x%X\n",
7643                             depth,
7644                             (int) nextchr, ST.c1, ST.c2)
7645                     );
7646                     state_num = CURLYM_B_fail;
7647                     goto reenter_switch;
7648                 }
7649             }
7650 
7651 	    if (ST.me->flags) {
7652 		/* emulate CLOSE: mark current A as captured */
7653 		I32 paren = ST.me->flags;
7654 		if (ST.count) {
7655 		    rex->offs[paren].start
7656 			= HOPc(locinput, -ST.alen) - reginfo->strbeg;
7657 		    rex->offs[paren].end = locinput - reginfo->strbeg;
7658 		    if ((U32)paren > rex->lastparen)
7659 			rex->lastparen = paren;
7660 		    rex->lastcloseparen = paren;
7661 		}
7662 		else
7663 		    rex->offs[paren].end = -1;
7664 
7665                 if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
7666 		{
7667 		    if (ST.count)
7668 	                goto fake_end;
7669 	            else
7670 	                sayNO;
7671 	        }
7672 	    }
7673 
7674 	    PUSH_STATE_GOTO(CURLYM_B, ST.B, locinput); /* match B */
7675 	    NOT_REACHED; /* NOTREACHED */
7676 
7677 	case CURLYM_B_fail: /* just failed to match a B */
7678 	    REGCP_UNWIND(ST.cp);
7679             UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
7680 	    if (ST.minmod) {
7681 		I32 max = ARG2(ST.me);
7682 		if (max != REG_INFTY && ST.count == max)
7683 		    sayNO;
7684 		goto curlym_do_A; /* try to match a further A */
7685 	    }
7686 	    /* backtrack one A */
7687 	    if (ST.count == ARG1(ST.me) /* min */)
7688 		sayNO;
7689 	    ST.count--;
7690 	    SET_locinput(HOPc(locinput, -ST.alen));
7691 	    goto curlym_do_B; /* try to match B */
7692 
7693 #undef ST
7694 #define ST st->u.curly
7695 
7696 #define CURLY_SETPAREN(paren, success) \
7697     if (paren) { \
7698 	if (success) { \
7699 	    rex->offs[paren].start = HOPc(locinput, -1) - reginfo->strbeg; \
7700 	    rex->offs[paren].end = locinput - reginfo->strbeg; \
7701 	    if (paren > rex->lastparen) \
7702 		rex->lastparen = paren; \
7703 	    rex->lastcloseparen = paren; \
7704 	} \
7705 	else { \
7706 	    rex->offs[paren].end = -1; \
7707 	    rex->lastparen      = ST.lastparen; \
7708 	    rex->lastcloseparen = ST.lastcloseparen; \
7709 	} \
7710     }
7711 
7712         case STAR:		/*  /A*B/ where A is width 1 char */
7713 	    ST.paren = 0;
7714 	    ST.min = 0;
7715 	    ST.max = REG_INFTY;
7716 	    scan = NEXTOPER(scan);
7717 	    goto repeat;
7718 
7719         case PLUS:		/*  /A+B/ where A is width 1 char */
7720 	    ST.paren = 0;
7721 	    ST.min = 1;
7722 	    ST.max = REG_INFTY;
7723 	    scan = NEXTOPER(scan);
7724 	    goto repeat;
7725 
7726 	case CURLYN:		/*  /(A){m,n}B/ where A is width 1 char */
7727             ST.paren = scan->flags;	/* Which paren to set */
7728             ST.lastparen      = rex->lastparen;
7729 	    ST.lastcloseparen = rex->lastcloseparen;
7730 	    if (ST.paren > maxopenparen)
7731 		maxopenparen = ST.paren;
7732 	    ST.min = ARG1(scan);  /* min to match */
7733 	    ST.max = ARG2(scan);  /* max to match */
7734             if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
7735             {
7736 	        ST.min=1;
7737 	        ST.max=1;
7738 	    }
7739             scan = regnext(NEXTOPER(scan) + NODE_STEP_REGNODE);
7740 	    goto repeat;
7741 
7742 	case CURLY:		/*  /A{m,n}B/ where A is width 1 char */
7743 	    ST.paren = 0;
7744 	    ST.min = ARG1(scan);  /* min to match */
7745 	    ST.max = ARG2(scan);  /* max to match */
7746 	    scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
7747 	  repeat:
7748 	    /*
7749 	    * Lookahead to avoid useless match attempts
7750 	    * when we know what character comes next.
7751 	    *
7752 	    * Used to only do .*x and .*?x, but now it allows
7753 	    * for )'s, ('s and (?{ ... })'s to be in the way
7754 	    * of the quantifier and the EXACT-like node.  -- japhy
7755 	    */
7756 
7757 	    assert(ST.min <= ST.max);
7758             if (! HAS_TEXT(next) && ! JUMPABLE(next)) {
7759                 ST.c1 = ST.c2 = CHRTEST_VOID;
7760             }
7761             else {
7762 		regnode *text_node = next;
7763 
7764 		if (! HAS_TEXT(text_node))
7765 		    FIND_NEXT_IMPT(text_node);
7766 
7767 		if (! HAS_TEXT(text_node))
7768 		    ST.c1 = ST.c2 = CHRTEST_VOID;
7769 		else {
7770 		    if ( PL_regkind[OP(text_node)] != EXACT ) {
7771 			ST.c1 = ST.c2 = CHRTEST_VOID;
7772 		    }
7773 		    else {
7774 
7775                     /*  Currently we only get here when
7776 
7777                         PL_rekind[OP(text_node)] == EXACT
7778 
7779                         if this changes back then the macro for IS_TEXT and
7780                         friends need to change. */
7781                         if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
7782                            text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8,
7783                            reginfo))
7784                         {
7785                             sayNO;
7786                         }
7787                     }
7788 		}
7789 	    }
7790 
7791 	    ST.A = scan;
7792 	    ST.B = next;
7793 	    if (minmod) {
7794                 char *li = locinput;
7795 		minmod = 0;
7796 		if (ST.min &&
7797                         regrepeat(rex, &li, ST.A, reginfo, ST.min, depth)
7798                             < ST.min)
7799 		    sayNO;
7800                 SET_locinput(li);
7801 		ST.count = ST.min;
7802 		REGCP_SET(ST.cp);
7803 		if (ST.c1 == CHRTEST_VOID)
7804 		    goto curly_try_B_min;
7805 
7806 		ST.oldloc = locinput;
7807 
7808 		/* set ST.maxpos to the furthest point along the
7809 		 * string that could possibly match */
7810 		if  (ST.max == REG_INFTY) {
7811 		    ST.maxpos = reginfo->strend - 1;
7812 		    if (utf8_target)
7813 			while (UTF8_IS_CONTINUATION(*(U8*)ST.maxpos))
7814 			    ST.maxpos--;
7815 		}
7816 		else if (utf8_target) {
7817 		    int m = ST.max - ST.min;
7818 		    for (ST.maxpos = locinput;
7819 			 m >0 && ST.maxpos < reginfo->strend; m--)
7820 			ST.maxpos += UTF8SKIP(ST.maxpos);
7821 		}
7822 		else {
7823 		    ST.maxpos = locinput + ST.max - ST.min;
7824 		    if (ST.maxpos >= reginfo->strend)
7825 			ST.maxpos = reginfo->strend - 1;
7826 		}
7827 		goto curly_try_B_min_known;
7828 
7829 	    }
7830 	    else {
7831                 /* avoid taking address of locinput, so it can remain
7832                  * a register var */
7833                 char *li = locinput;
7834 		ST.count = regrepeat(rex, &li, ST.A, reginfo, ST.max, depth);
7835 		if (ST.count < ST.min)
7836 		    sayNO;
7837                 SET_locinput(li);
7838 		if ((ST.count > ST.min)
7839 		    && (PL_regkind[OP(ST.B)] == EOL) && (OP(ST.B) != MEOL))
7840 		{
7841 		    /* A{m,n} must come at the end of the string, there's
7842 		     * no point in backing off ... */
7843 		    ST.min = ST.count;
7844 		    /* ...except that $ and \Z can match before *and* after
7845 		       newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
7846 		       We may back off by one in this case. */
7847 		    if (UCHARAT(locinput - 1) == '\n' && OP(ST.B) != EOS)
7848 			ST.min--;
7849 		}
7850 		REGCP_SET(ST.cp);
7851 		goto curly_try_B_max;
7852 	    }
7853 	    NOT_REACHED; /* NOTREACHED */
7854 
7855 	case CURLY_B_min_known_fail:
7856 	    /* failed to find B in a non-greedy match where c1,c2 valid */
7857 
7858 	    REGCP_UNWIND(ST.cp);
7859             if (ST.paren) {
7860                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
7861             }
7862 	    /* Couldn't or didn't -- move forward. */
7863 	    ST.oldloc = locinput;
7864 	    if (utf8_target)
7865 		locinput += UTF8SKIP(locinput);
7866 	    else
7867 		locinput++;
7868 	    ST.count++;
7869 	  curly_try_B_min_known:
7870 	     /* find the next place where 'B' could work, then call B */
7871 	    {
7872 		int n;
7873 		if (utf8_target) {
7874 		    n = (ST.oldloc == locinput) ? 0 : 1;
7875 		    if (ST.c1 == ST.c2) {
7876 			/* set n to utf8_distance(oldloc, locinput) */
7877 			while (locinput <= ST.maxpos
7878                               && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput)))
7879                         {
7880 			    locinput += UTF8SKIP(locinput);
7881 			    n++;
7882 			}
7883 		    }
7884 		    else {
7885 			/* set n to utf8_distance(oldloc, locinput) */
7886 			while (locinput <= ST.maxpos
7887                               && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
7888                               && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
7889                         {
7890 			    locinput += UTF8SKIP(locinput);
7891 			    n++;
7892 			}
7893 		    }
7894 		}
7895 		else {  /* Not utf8_target */
7896 		    if (ST.c1 == ST.c2) {
7897 			while (locinput <= ST.maxpos &&
7898 			       UCHARAT(locinput) != ST.c1)
7899 			    locinput++;
7900 		    }
7901 		    else {
7902 			while (locinput <= ST.maxpos
7903 			       && UCHARAT(locinput) != ST.c1
7904 			       && UCHARAT(locinput) != ST.c2)
7905 			    locinput++;
7906 		    }
7907 		    n = locinput - ST.oldloc;
7908 		}
7909 		if (locinput > ST.maxpos)
7910 		    sayNO;
7911 		if (n) {
7912                     /* In /a{m,n}b/, ST.oldloc is at "a" x m, locinput is
7913                      * at b; check that everything between oldloc and
7914                      * locinput matches */
7915                     char *li = ST.oldloc;
7916 		    ST.count += n;
7917 		    if (regrepeat(rex, &li, ST.A, reginfo, n, depth) < n)
7918 			sayNO;
7919                     assert(n == REG_INFTY || locinput == li);
7920 		}
7921 		CURLY_SETPAREN(ST.paren, ST.count);
7922                 if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
7923 		    goto fake_end;
7924 		PUSH_STATE_GOTO(CURLY_B_min_known, ST.B, locinput);
7925 	    }
7926 	    NOT_REACHED; /* NOTREACHED */
7927 
7928 	case CURLY_B_min_fail:
7929 	    /* failed to find B in a non-greedy match where c1,c2 invalid */
7930 
7931 	    REGCP_UNWIND(ST.cp);
7932             if (ST.paren) {
7933                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
7934             }
7935 	    /* failed -- move forward one */
7936             {
7937                 char *li = locinput;
7938                 if (!regrepeat(rex, &li, ST.A, reginfo, 1, depth)) {
7939                     sayNO;
7940                 }
7941                 locinput = li;
7942             }
7943             {
7944 		ST.count++;
7945 		if (ST.count <= ST.max || (ST.max == REG_INFTY &&
7946 			ST.count > 0)) /* count overflow ? */
7947 		{
7948 		  curly_try_B_min:
7949 		    CURLY_SETPAREN(ST.paren, ST.count);
7950                     if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
7951                         goto fake_end;
7952 		    PUSH_STATE_GOTO(CURLY_B_min, ST.B, locinput);
7953 		}
7954 	    }
7955             sayNO;
7956 	    NOT_REACHED; /* NOTREACHED */
7957 
7958           curly_try_B_max:
7959 	    /* a successful greedy match: now try to match B */
7960             if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
7961                 goto fake_end;
7962 	    {
7963 		bool could_match = locinput < reginfo->strend;
7964 
7965 		/* If it could work, try it. */
7966                 if (ST.c1 != CHRTEST_VOID && could_match) {
7967                     if (! UTF8_IS_INVARIANT(UCHARAT(locinput)) && utf8_target)
7968                     {
7969                         could_match = memEQ(locinput,
7970                                             ST.c1_utf8,
7971                                             UTF8SKIP(locinput))
7972                                     || memEQ(locinput,
7973                                              ST.c2_utf8,
7974                                              UTF8SKIP(locinput));
7975                     }
7976                     else {
7977                         could_match = UCHARAT(locinput) == ST.c1
7978                                       || UCHARAT(locinput) == ST.c2;
7979                     }
7980                 }
7981                 if (ST.c1 == CHRTEST_VOID || could_match) {
7982 		    CURLY_SETPAREN(ST.paren, ST.count);
7983 		    PUSH_STATE_GOTO(CURLY_B_max, ST.B, locinput);
7984 		    NOT_REACHED; /* NOTREACHED */
7985 		}
7986 	    }
7987 	    /* FALLTHROUGH */
7988 
7989 	case CURLY_B_max_fail:
7990 	    /* failed to find B in a greedy match */
7991 
7992 	    REGCP_UNWIND(ST.cp);
7993             if (ST.paren) {
7994                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
7995             }
7996 	    /*  back up. */
7997 	    if (--ST.count < ST.min)
7998 		sayNO;
7999 	    locinput = HOPc(locinput, -1);
8000 	    goto curly_try_B_max;
8001 
8002 #undef ST
8003 
8004 	case END: /*  last op of main pattern  */
8005           fake_end:
8006 	    if (cur_eval) {
8007 		/* we've just finished A in /(??{A})B/; now continue with B */
8008                 SET_RECURSE_LOCINPUT("FAKE-END[before]", CUR_EVAL.prev_recurse_locinput);
8009 		st->u.eval.prev_rex = rex_sv;		/* inner */
8010 
8011                 /* Save *all* the positions. */
8012 		st->u.eval.cp = regcppush(rex, 0, maxopenparen);
8013                 rex_sv = CUR_EVAL.prev_rex;
8014 		is_utf8_pat = reginfo->is_utf8_pat = cBOOL(RX_UTF8(rex_sv));
8015 		SET_reg_curpm(rex_sv);
8016 		rex = ReANY(rex_sv);
8017 		rexi = RXi_GET(rex);
8018 
8019                 st->u.eval.prev_curlyx = cur_curlyx;
8020                 cur_curlyx = CUR_EVAL.prev_curlyx;
8021 
8022 		REGCP_SET(st->u.eval.lastcp);
8023 
8024 		/* Restore parens of the outer rex without popping the
8025 		 * savestack */
8026                 S_regcp_restore(aTHX_ rex, CUR_EVAL.lastcp,
8027                                         &maxopenparen);
8028 
8029 		st->u.eval.prev_eval = cur_eval;
8030                 cur_eval = CUR_EVAL.prev_eval;
8031 		DEBUG_EXECUTE_r(
8032                     Perl_re_exec_indentf( aTHX_  "EVAL trying tail ... (cur_eval=%p)\n",
8033                                       depth, cur_eval););
8034                 if ( nochange_depth )
8035 	            nochange_depth--;
8036 
8037                 SET_RECURSE_LOCINPUT("FAKE-END[after]", cur_eval->locinput);
8038 
8039                 PUSH_YES_STATE_GOTO(EVAL_AB, st->u.eval.prev_eval->u.eval.B,
8040                                     locinput); /* match B */
8041 	    }
8042 
8043 	    if (locinput < reginfo->till) {
8044                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
8045                                       "%sMatch possible, but length=%ld is smaller than requested=%ld, failing!%s\n",
8046 				      PL_colors[4],
8047 				      (long)(locinput - startpos),
8048 				      (long)(reginfo->till - startpos),
8049 				      PL_colors[5]));
8050 
8051 		sayNO_SILENT;		/* Cannot match: too short. */
8052 	    }
8053 	    sayYES;			/* Success! */
8054 
8055 	case SUCCEED: /* successful SUSPEND/UNLESSM/IFMATCH/CURLYM */
8056 	    DEBUG_EXECUTE_r(
8057             Perl_re_exec_indentf( aTHX_  "%ssubpattern success...%s\n",
8058                 depth, PL_colors[4], PL_colors[5]));
8059 	    sayYES;			/* Success! */
8060 
8061 #undef  ST
8062 #define ST st->u.ifmatch
8063 
8064         {
8065             char *newstart;
8066 
8067 	case SUSPEND:	/* (?>A) */
8068 	    ST.wanted = 1;
8069 	    newstart = locinput;
8070 	    goto do_ifmatch;
8071 
8072 	case UNLESSM:	/* -ve lookaround: (?!A), or with flags, (?<!A) */
8073 	    ST.wanted = 0;
8074 	    goto ifmatch_trivial_fail_test;
8075 
8076 	case IFMATCH:	/* +ve lookaround: (?=A), or with flags, (?<=A) */
8077 	    ST.wanted = 1;
8078 	  ifmatch_trivial_fail_test:
8079 	    if (scan->flags) {
8080 		char * const s = HOPBACKc(locinput, scan->flags);
8081 		if (!s) {
8082 		    /* trivial fail */
8083 		    if (logical) {
8084 			logical = 0;
8085 			sw = 1 - cBOOL(ST.wanted);
8086 		    }
8087 		    else if (ST.wanted)
8088 			sayNO;
8089 		    next = scan + ARG(scan);
8090 		    if (next == scan)
8091 			next = NULL;
8092 		    break;
8093 		}
8094 		newstart = s;
8095 	    }
8096 	    else
8097 		newstart = locinput;
8098 
8099 	  do_ifmatch:
8100 	    ST.me = scan;
8101 	    ST.logical = logical;
8102 	    logical = 0; /* XXX: reset state of logical once it has been saved into ST */
8103 
8104 	    /* execute body of (?...A) */
8105 	    PUSH_YES_STATE_GOTO(IFMATCH_A, NEXTOPER(NEXTOPER(scan)), newstart);
8106 	    NOT_REACHED; /* NOTREACHED */
8107         }
8108 
8109 	case IFMATCH_A_fail: /* body of (?...A) failed */
8110 	    ST.wanted = !ST.wanted;
8111 	    /* FALLTHROUGH */
8112 
8113 	case IFMATCH_A: /* body of (?...A) succeeded */
8114 	    if (ST.logical) {
8115 		sw = cBOOL(ST.wanted);
8116 	    }
8117 	    else if (!ST.wanted)
8118 		sayNO;
8119 
8120 	    if (OP(ST.me) != SUSPEND) {
8121                 /* restore old position except for (?>...) */
8122 		locinput = st->locinput;
8123 	    }
8124 	    scan = ST.me + ARG(ST.me);
8125 	    if (scan == ST.me)
8126 		scan = NULL;
8127 	    continue; /* execute B */
8128 
8129 #undef ST
8130 
8131 	case LONGJMP: /*  alternative with many branches compiles to
8132                        * (BRANCHJ; EXACT ...; LONGJMP ) x N */
8133 	    next = scan + ARG(scan);
8134 	    if (next == scan)
8135 		next = NULL;
8136 	    break;
8137 
8138 	case COMMIT:  /*  (*COMMIT)  */
8139 	    reginfo->cutpoint = reginfo->strend;
8140 	    /* FALLTHROUGH */
8141 
8142 	case PRUNE:   /*  (*PRUNE)   */
8143             if (scan->flags)
8144 	        sv_yes_mark = sv_commit = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
8145 	    PUSH_STATE_GOTO(COMMIT_next, next, locinput);
8146 	    NOT_REACHED; /* NOTREACHED */
8147 
8148 	case COMMIT_next_fail:
8149 	    no_final = 1;
8150 	    /* FALLTHROUGH */
8151             sayNO;
8152             NOT_REACHED; /* NOTREACHED */
8153 
8154 	case OPFAIL:   /* (*FAIL)  */
8155             if (scan->flags)
8156                 sv_commit = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
8157             if (logical) {
8158                 /* deal with (?(?!)X|Y) properly,
8159                  * make sure we trigger the no branch
8160                  * of the trailing IFTHEN structure*/
8161                 sw= 0;
8162                 break;
8163             } else {
8164                 sayNO;
8165             }
8166 	    NOT_REACHED; /* NOTREACHED */
8167 
8168 #define ST st->u.mark
8169         case MARKPOINT: /*  (*MARK:foo)  */
8170             ST.prev_mark = mark_state;
8171             ST.mark_name = sv_commit = sv_yes_mark
8172                 = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
8173             mark_state = st;
8174             ST.mark_loc = locinput;
8175             PUSH_YES_STATE_GOTO(MARKPOINT_next, next, locinput);
8176             NOT_REACHED; /* NOTREACHED */
8177 
8178         case MARKPOINT_next:
8179             mark_state = ST.prev_mark;
8180             sayYES;
8181             NOT_REACHED; /* NOTREACHED */
8182 
8183         case MARKPOINT_next_fail:
8184             if (popmark && sv_eq(ST.mark_name,popmark))
8185             {
8186                 if (ST.mark_loc > startpoint)
8187 	            reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
8188                 popmark = NULL; /* we found our mark */
8189                 sv_commit = ST.mark_name;
8190 
8191                 DEBUG_EXECUTE_r({
8192                         Perl_re_exec_indentf( aTHX_  "%ssetting cutpoint to mark:%"SVf"...%s\n",
8193                             depth,
8194 		            PL_colors[4], SVfARG(sv_commit), PL_colors[5]);
8195 		});
8196             }
8197             mark_state = ST.prev_mark;
8198             sv_yes_mark = mark_state ?
8199                 mark_state->u.mark.mark_name : NULL;
8200             sayNO;
8201             NOT_REACHED; /* NOTREACHED */
8202 
8203         case SKIP:  /*  (*SKIP)  */
8204             if (!scan->flags) {
8205                 /* (*SKIP) : if we fail we cut here*/
8206                 ST.mark_name = NULL;
8207                 ST.mark_loc = locinput;
8208                 PUSH_STATE_GOTO(SKIP_next,next, locinput);
8209             } else {
8210                 /* (*SKIP:NAME) : if there is a (*MARK:NAME) fail where it was,
8211                    otherwise do nothing.  Meaning we need to scan
8212                  */
8213                 regmatch_state *cur = mark_state;
8214                 SV *find = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
8215 
8216                 while (cur) {
8217                     if ( sv_eq( cur->u.mark.mark_name,
8218                                 find ) )
8219                     {
8220                         ST.mark_name = find;
8221                         PUSH_STATE_GOTO( SKIP_next, next, locinput);
8222                     }
8223                     cur = cur->u.mark.prev_mark;
8224                 }
8225             }
8226             /* Didn't find our (*MARK:NAME) so ignore this (*SKIP:NAME) */
8227             break;
8228 
8229 	case SKIP_next_fail:
8230 	    if (ST.mark_name) {
8231 	        /* (*CUT:NAME) - Set up to search for the name as we
8232 	           collapse the stack*/
8233 	        popmark = ST.mark_name;
8234 	    } else {
8235 	        /* (*CUT) - No name, we cut here.*/
8236 	        if (ST.mark_loc > startpoint)
8237 	            reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
8238 	        /* but we set sv_commit to latest mark_name if there
8239 	           is one so they can test to see how things lead to this
8240 	           cut */
8241                 if (mark_state)
8242                     sv_commit=mark_state->u.mark.mark_name;
8243             }
8244             no_final = 1;
8245             sayNO;
8246             NOT_REACHED; /* NOTREACHED */
8247 #undef ST
8248 
8249         case LNBREAK: /* \R */
8250             if ((n=is_LNBREAK_safe(locinput, reginfo->strend, utf8_target))) {
8251                 locinput += n;
8252             } else
8253                 sayNO;
8254             break;
8255 
8256 	default:
8257 	    PerlIO_printf(Perl_error_log, "%"UVxf" %d\n",
8258 			  PTR2UV(scan), OP(scan));
8259 	    Perl_croak(aTHX_ "regexp memory corruption");
8260 
8261         /* this is a point to jump to in order to increment
8262          * locinput by one character */
8263           increment_locinput:
8264             assert(!NEXTCHR_IS_EOS);
8265             if (utf8_target) {
8266                 locinput += PL_utf8skip[nextchr];
8267                 /* locinput is allowed to go 1 char off the end, but not 2+ */
8268                 if (locinput > reginfo->strend)
8269                     sayNO;
8270             }
8271             else
8272                 locinput++;
8273             break;
8274 
8275 	} /* end switch */
8276 
8277         /* switch break jumps here */
8278 	scan = next; /* prepare to execute the next op and ... */
8279 	continue;    /* ... jump back to the top, reusing st */
8280         /* NOTREACHED */
8281 
8282       push_yes_state:
8283 	/* push a state that backtracks on success */
8284 	st->u.yes.prev_yes_state = yes_state;
8285 	yes_state = st;
8286 	/* FALLTHROUGH */
8287       push_state:
8288 	/* push a new regex state, then continue at scan  */
8289 	{
8290 	    regmatch_state *newst;
8291 
8292 	    DEBUG_STACK_r({
8293 	        regmatch_state *cur = st;
8294 	        regmatch_state *curyes = yes_state;
8295 	        int curd = depth;
8296 	        regmatch_slab *slab = PL_regmatch_slab;
8297                 for (;curd > -1 && (depth-curd < 3);cur--,curd--) {
8298                     if (cur < SLAB_FIRST(slab)) {
8299                 	slab = slab->prev;
8300                 	cur = SLAB_LAST(slab);
8301                     }
8302                     Perl_re_exec_indentf( aTHX_ "#%-3d %-10s %s\n",
8303                         depth,
8304                         curd, PL_reg_name[cur->resume_state],
8305                         (curyes == cur) ? "yes" : ""
8306                     );
8307                     if (curyes == cur)
8308 	                curyes = cur->u.yes.prev_yes_state;
8309                 }
8310             } else
8311                 DEBUG_STATE_pp("push")
8312             );
8313 	    depth++;
8314 	    st->locinput = locinput;
8315 	    newst = st+1;
8316 	    if (newst >  SLAB_LAST(PL_regmatch_slab))
8317 		newst = S_push_slab(aTHX);
8318 	    PL_regmatch_state = newst;
8319 
8320 	    locinput = pushinput;
8321 	    st = newst;
8322 	    continue;
8323             /* NOTREACHED */
8324 	}
8325     }
8326 #ifdef SOLARIS_BAD_OPTIMIZER
8327 #  undef PL_charclass
8328 #endif
8329 
8330     /*
8331     * We get here only if there's trouble -- normally "case END" is
8332     * the terminating point.
8333     */
8334     Perl_croak(aTHX_ "corrupted regexp pointers");
8335     NOT_REACHED; /* NOTREACHED */
8336 
8337   yes:
8338     if (yes_state) {
8339 	/* we have successfully completed a subexpression, but we must now
8340 	 * pop to the state marked by yes_state and continue from there */
8341 	assert(st != yes_state);
8342 #ifdef DEBUGGING
8343 	while (st != yes_state) {
8344 	    st--;
8345 	    if (st < SLAB_FIRST(PL_regmatch_slab)) {
8346 		PL_regmatch_slab = PL_regmatch_slab->prev;
8347 		st = SLAB_LAST(PL_regmatch_slab);
8348 	    }
8349 	    DEBUG_STATE_r({
8350 	        if (no_final) {
8351 	            DEBUG_STATE_pp("pop (no final)");
8352 	        } else {
8353 	            DEBUG_STATE_pp("pop (yes)");
8354 	        }
8355 	    });
8356 	    depth--;
8357 	}
8358 #else
8359 	while (yes_state < SLAB_FIRST(PL_regmatch_slab)
8360 	    || yes_state > SLAB_LAST(PL_regmatch_slab))
8361 	{
8362 	    /* not in this slab, pop slab */
8363 	    depth -= (st - SLAB_FIRST(PL_regmatch_slab) + 1);
8364 	    PL_regmatch_slab = PL_regmatch_slab->prev;
8365 	    st = SLAB_LAST(PL_regmatch_slab);
8366 	}
8367 	depth -= (st - yes_state);
8368 #endif
8369 	st = yes_state;
8370 	yes_state = st->u.yes.prev_yes_state;
8371 	PL_regmatch_state = st;
8372 
8373         if (no_final)
8374             locinput= st->locinput;
8375 	state_num = st->resume_state + no_final;
8376 	goto reenter_switch;
8377     }
8378 
8379     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "%sMatch successful!%s\n",
8380 			  PL_colors[4], PL_colors[5]));
8381 
8382     if (reginfo->info_aux_eval) {
8383 	/* each successfully executed (?{...}) block does the equivalent of
8384 	 *   local $^R = do {...}
8385 	 * When popping the save stack, all these locals would be undone;
8386 	 * bypass this by setting the outermost saved $^R to the latest
8387 	 * value */
8388         /* I dont know if this is needed or works properly now.
8389          * see code related to PL_replgv elsewhere in this file.
8390          * Yves
8391          */
8392 	if (oreplsv != GvSV(PL_replgv))
8393 	    sv_setsv(oreplsv, GvSV(PL_replgv));
8394     }
8395     result = 1;
8396     goto final_exit;
8397 
8398   no:
8399     DEBUG_EXECUTE_r(
8400         Perl_re_exec_indentf( aTHX_  "%sfailed...%s\n",
8401             depth,
8402             PL_colors[4], PL_colors[5])
8403 	);
8404 
8405   no_silent:
8406     if (no_final) {
8407         if (yes_state) {
8408             goto yes;
8409         } else {
8410             goto final_exit;
8411         }
8412     }
8413     if (depth) {
8414 	/* there's a previous state to backtrack to */
8415 	st--;
8416 	if (st < SLAB_FIRST(PL_regmatch_slab)) {
8417 	    PL_regmatch_slab = PL_regmatch_slab->prev;
8418 	    st = SLAB_LAST(PL_regmatch_slab);
8419 	}
8420 	PL_regmatch_state = st;
8421 	locinput= st->locinput;
8422 
8423 	DEBUG_STATE_pp("pop");
8424 	depth--;
8425 	if (yes_state == st)
8426 	    yes_state = st->u.yes.prev_yes_state;
8427 
8428 	state_num = st->resume_state + 1; /* failure = success + 1 */
8429 	goto reenter_switch;
8430     }
8431     result = 0;
8432 
8433   final_exit:
8434     if (rex->intflags & PREGf_VERBARG_SEEN) {
8435         SV *sv_err = get_sv("REGERROR", 1);
8436         SV *sv_mrk = get_sv("REGMARK", 1);
8437         if (result) {
8438             sv_commit = &PL_sv_no;
8439             if (!sv_yes_mark)
8440                 sv_yes_mark = &PL_sv_yes;
8441         } else {
8442             if (!sv_commit)
8443                 sv_commit = &PL_sv_yes;
8444             sv_yes_mark = &PL_sv_no;
8445         }
8446         assert(sv_err);
8447         assert(sv_mrk);
8448         sv_setsv(sv_err, sv_commit);
8449         sv_setsv(sv_mrk, sv_yes_mark);
8450     }
8451 
8452 
8453     if (last_pushed_cv) {
8454 	dSP;
8455 	POP_MULTICALL;
8456         PERL_UNUSED_VAR(SP);
8457     }
8458 
8459     assert(!result ||  locinput - reginfo->strbeg >= 0);
8460     return result ?  locinput - reginfo->strbeg : -1;
8461 }
8462 
8463 /*
8464  - regrepeat - repeatedly match something simple, report how many
8465  *
8466  * What 'simple' means is a node which can be the operand of a quantifier like
8467  * '+', or {1,3}
8468  *
8469  * startposp - pointer a pointer to the start position.  This is updated
8470  *             to point to the byte following the highest successful
8471  *             match.
8472  * p         - the regnode to be repeatedly matched against.
8473  * reginfo   - struct holding match state, such as strend
8474  * max       - maximum number of things to match.
8475  * depth     - (for debugging) backtracking depth.
8476  */
8477 STATIC I32
8478 S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
8479             regmatch_info *const reginfo, I32 max, int depth)
8480 {
8481     char *scan;     /* Pointer to current position in target string */
8482     I32 c;
8483     char *loceol = reginfo->strend;   /* local version */
8484     I32 hardcount = 0;  /* How many matches so far */
8485     bool utf8_target = reginfo->is_utf8_target;
8486     unsigned int to_complement = 0;  /* Invert the result? */
8487     UV utf8_flags;
8488     _char_class_number classnum;
8489 #ifndef DEBUGGING
8490     PERL_UNUSED_ARG(depth);
8491 #endif
8492 
8493     PERL_ARGS_ASSERT_REGREPEAT;
8494 
8495     scan = *startposp;
8496     if (max == REG_INFTY)
8497 	max = I32_MAX;
8498     else if (! utf8_target && loceol - scan > max)
8499 	loceol = scan + max;
8500 
8501     /* Here, for the case of a non-UTF-8 target we have adjusted <loceol> down
8502      * to the maximum of how far we should go in it (leaving it set to the real
8503      * end, if the maximum permissible would take us beyond that).  This allows
8504      * us to make the loop exit condition that we haven't gone past <loceol> to
8505      * also mean that we haven't exceeded the max permissible count, saving a
8506      * test each time through the loop.  But it assumes that the OP matches a
8507      * single byte, which is true for most of the OPs below when applied to a
8508      * non-UTF-8 target.  Those relatively few OPs that don't have this
8509      * characteristic will have to compensate.
8510      *
8511      * There is no adjustment for UTF-8 targets, as the number of bytes per
8512      * character varies.  OPs will have to test both that the count is less
8513      * than the max permissible (using <hardcount> to keep track), and that we
8514      * are still within the bounds of the string (using <loceol>.  A few OPs
8515      * match a single byte no matter what the encoding.  They can omit the max
8516      * test if, for the UTF-8 case, they do the adjustment that was skipped
8517      * above.
8518      *
8519      * Thus, the code above sets things up for the common case; and exceptional
8520      * cases need extra work; the common case is to make sure <scan> doesn't
8521      * go past <loceol>, and for UTF-8 to also use <hardcount> to make sure the
8522      * count doesn't exceed the maximum permissible */
8523 
8524     switch (OP(p)) {
8525     case REG_ANY:
8526 	if (utf8_target) {
8527 	    while (scan < loceol && hardcount < max && *scan != '\n') {
8528 		scan += UTF8SKIP(scan);
8529 		hardcount++;
8530 	    }
8531 	} else {
8532 	    while (scan < loceol && *scan != '\n')
8533 		scan++;
8534 	}
8535 	break;
8536     case SANY:
8537         if (utf8_target) {
8538 	    while (scan < loceol && hardcount < max) {
8539 	        scan += UTF8SKIP(scan);
8540 		hardcount++;
8541 	    }
8542 	}
8543 	else
8544 	    scan = loceol;
8545 	break;
8546     case EXACTL:
8547         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
8548         if (utf8_target && UTF8_IS_ABOVE_LATIN1(*scan)) {
8549             _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(scan, loceol);
8550         }
8551         /* FALLTHROUGH */
8552     case EXACT:
8553         assert(STR_LEN(p) == reginfo->is_utf8_pat ? UTF8SKIP(STRING(p)) : 1);
8554 
8555 	c = (U8)*STRING(p);
8556 
8557         /* Can use a simple loop if the pattern char to match on is invariant
8558          * under UTF-8, or both target and pattern aren't UTF-8.  Note that we
8559          * can use UTF8_IS_INVARIANT() even if the pattern isn't UTF-8, as it's
8560          * true iff it doesn't matter if the argument is in UTF-8 or not */
8561         if (UTF8_IS_INVARIANT(c) || (! utf8_target && ! reginfo->is_utf8_pat)) {
8562             if (utf8_target && loceol - scan > max) {
8563                 /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
8564                  * since here, to match at all, 1 char == 1 byte */
8565                 loceol = scan + max;
8566             }
8567 	    while (scan < loceol && UCHARAT(scan) == c) {
8568 		scan++;
8569 	    }
8570 	}
8571 	else if (reginfo->is_utf8_pat) {
8572             if (utf8_target) {
8573                 STRLEN scan_char_len;
8574 
8575                 /* When both target and pattern are UTF-8, we have to do
8576                  * string EQ */
8577                 while (hardcount < max
8578                        && scan < loceol
8579                        && (scan_char_len = UTF8SKIP(scan)) <= STR_LEN(p)
8580                        && memEQ(scan, STRING(p), scan_char_len))
8581                 {
8582                     scan += scan_char_len;
8583                     hardcount++;
8584                 }
8585             }
8586             else if (! UTF8_IS_ABOVE_LATIN1(c)) {
8587 
8588                 /* Target isn't utf8; convert the character in the UTF-8
8589                  * pattern to non-UTF8, and do a simple loop */
8590                 c = EIGHT_BIT_UTF8_TO_NATIVE(c, *(STRING(p) + 1));
8591                 while (scan < loceol && UCHARAT(scan) == c) {
8592                     scan++;
8593                 }
8594             } /* else pattern char is above Latin1, can't possibly match the
8595                  non-UTF-8 target */
8596         }
8597         else {
8598 
8599             /* Here, the string must be utf8; pattern isn't, and <c> is
8600              * different in utf8 than not, so can't compare them directly.
8601              * Outside the loop, find the two utf8 bytes that represent c, and
8602              * then look for those in sequence in the utf8 string */
8603 	    U8 high = UTF8_TWO_BYTE_HI(c);
8604 	    U8 low = UTF8_TWO_BYTE_LO(c);
8605 
8606 	    while (hardcount < max
8607 		    && scan + 1 < loceol
8608 		    && UCHARAT(scan) == high
8609 		    && UCHARAT(scan + 1) == low)
8610 	    {
8611 		scan += 2;
8612 		hardcount++;
8613 	    }
8614 	}
8615 	break;
8616 
8617     case EXACTFA_NO_TRIE:   /* This node only generated for non-utf8 patterns */
8618         assert(! reginfo->is_utf8_pat);
8619         /* FALLTHROUGH */
8620     case EXACTFA:
8621         utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
8622 	goto do_exactf;
8623 
8624     case EXACTFL:
8625         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
8626 	utf8_flags = FOLDEQ_LOCALE;
8627 	goto do_exactf;
8628 
8629     case EXACTF:   /* This node only generated for non-utf8 patterns */
8630         assert(! reginfo->is_utf8_pat);
8631         utf8_flags = 0;
8632         goto do_exactf;
8633 
8634     case EXACTFLU8:
8635         if (! utf8_target) {
8636             break;
8637         }
8638         utf8_flags =  FOLDEQ_LOCALE | FOLDEQ_S2_ALREADY_FOLDED
8639                                     | FOLDEQ_S2_FOLDS_SANE;
8640         goto do_exactf;
8641 
8642     case EXACTFU_SS:
8643     case EXACTFU:
8644 	utf8_flags = reginfo->is_utf8_pat ? FOLDEQ_S2_ALREADY_FOLDED : 0;
8645 
8646       do_exactf: {
8647         int c1, c2;
8648         U8 c1_utf8[UTF8_MAXBYTES+1], c2_utf8[UTF8_MAXBYTES+1];
8649 
8650         assert(STR_LEN(p) == reginfo->is_utf8_pat ? UTF8SKIP(STRING(p)) : 1);
8651 
8652         if (S_setup_EXACTISH_ST_c1_c2(aTHX_ p, &c1, c1_utf8, &c2, c2_utf8,
8653                                         reginfo))
8654         {
8655             if (c1 == CHRTEST_VOID) {
8656                 /* Use full Unicode fold matching */
8657                 char *tmpeol = reginfo->strend;
8658                 STRLEN pat_len = reginfo->is_utf8_pat ? UTF8SKIP(STRING(p)) : 1;
8659                 while (hardcount < max
8660                         && foldEQ_utf8_flags(scan, &tmpeol, 0, utf8_target,
8661                                              STRING(p), NULL, pat_len,
8662                                              reginfo->is_utf8_pat, utf8_flags))
8663                 {
8664                     scan = tmpeol;
8665                     tmpeol = reginfo->strend;
8666                     hardcount++;
8667                 }
8668             }
8669             else if (utf8_target) {
8670                 if (c1 == c2) {
8671                     while (scan < loceol
8672                            && hardcount < max
8673                            && memEQ(scan, c1_utf8, UTF8SKIP(scan)))
8674                     {
8675                         scan += UTF8SKIP(scan);
8676                         hardcount++;
8677                     }
8678                 }
8679                 else {
8680                     while (scan < loceol
8681                            && hardcount < max
8682                            && (memEQ(scan, c1_utf8, UTF8SKIP(scan))
8683                                || memEQ(scan, c2_utf8, UTF8SKIP(scan))))
8684                     {
8685                         scan += UTF8SKIP(scan);
8686                         hardcount++;
8687                     }
8688                 }
8689             }
8690             else if (c1 == c2) {
8691                 while (scan < loceol && UCHARAT(scan) == c1) {
8692                     scan++;
8693                 }
8694             }
8695             else {
8696                 while (scan < loceol &&
8697                     (UCHARAT(scan) == c1 || UCHARAT(scan) == c2))
8698                 {
8699                     scan++;
8700                 }
8701             }
8702 	}
8703 	break;
8704     }
8705     case ANYOFL:
8706         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
8707 
8708         if (ANYOFL_UTF8_LOCALE_REQD(FLAGS(p)) && ! IN_UTF8_CTYPE_LOCALE) {
8709             Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE), utf8_locale_required);
8710         }
8711         /* FALLTHROUGH */
8712     case ANYOFD:
8713     case ANYOF:
8714 	if (utf8_target) {
8715 	    while (hardcount < max
8716                    && scan < loceol
8717 		   && reginclass(prog, p, (U8*)scan, (U8*) loceol, utf8_target))
8718 	    {
8719 		scan += UTF8SKIP(scan);
8720 		hardcount++;
8721 	    }
8722 	} else {
8723 	    while (scan < loceol && REGINCLASS(prog, p, (U8*)scan, 0))
8724 		scan++;
8725 	}
8726 	break;
8727 
8728     /* The argument (FLAGS) to all the POSIX node types is the class number */
8729 
8730     case NPOSIXL:
8731         to_complement = 1;
8732         /* FALLTHROUGH */
8733 
8734     case POSIXL:
8735         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
8736 	if (! utf8_target) {
8737 	    while (scan < loceol && to_complement ^ cBOOL(isFOO_lc(FLAGS(p),
8738                                                                    *scan)))
8739             {
8740 		scan++;
8741             }
8742 	} else {
8743 	    while (hardcount < max && scan < loceol
8744                    && to_complement ^ cBOOL(isFOO_utf8_lc(FLAGS(p),
8745                                                                   (U8 *) scan)))
8746             {
8747                 scan += UTF8SKIP(scan);
8748 		hardcount++;
8749 	    }
8750 	}
8751 	break;
8752 
8753     case POSIXD:
8754         if (utf8_target) {
8755             goto utf8_posix;
8756         }
8757         /* FALLTHROUGH */
8758 
8759     case POSIXA:
8760         if (utf8_target && loceol - scan > max) {
8761 
8762             /* We didn't adjust <loceol> at the beginning of this routine
8763              * because is UTF-8, but it is actually ok to do so, since here, to
8764              * match, 1 char == 1 byte. */
8765             loceol = scan + max;
8766         }
8767         while (scan < loceol && _generic_isCC_A((U8) *scan, FLAGS(p))) {
8768 	    scan++;
8769 	}
8770 	break;
8771 
8772     case NPOSIXD:
8773         if (utf8_target) {
8774             to_complement = 1;
8775             goto utf8_posix;
8776         }
8777         /* FALLTHROUGH */
8778 
8779     case NPOSIXA:
8780         if (! utf8_target) {
8781             while (scan < loceol && ! _generic_isCC_A((U8) *scan, FLAGS(p))) {
8782                 scan++;
8783             }
8784         }
8785         else {
8786 
8787             /* The complement of something that matches only ASCII matches all
8788              * non-ASCII, plus everything in ASCII that isn't in the class. */
8789 	    while (hardcount < max && scan < loceol
8790                    && (! isASCII_utf8(scan)
8791                        || ! _generic_isCC_A((U8) *scan, FLAGS(p))))
8792             {
8793                 scan += UTF8SKIP(scan);
8794 		hardcount++;
8795 	    }
8796         }
8797         break;
8798 
8799     case NPOSIXU:
8800         to_complement = 1;
8801         /* FALLTHROUGH */
8802 
8803     case POSIXU:
8804 	if (! utf8_target) {
8805             while (scan < loceol && to_complement
8806                                 ^ cBOOL(_generic_isCC((U8) *scan, FLAGS(p))))
8807             {
8808                 scan++;
8809             }
8810 	}
8811 	else {
8812           utf8_posix:
8813             classnum = (_char_class_number) FLAGS(p);
8814             if (classnum < _FIRST_NON_SWASH_CC) {
8815 
8816                 /* Here, a swash is needed for above-Latin1 code points.
8817                  * Process as many Latin1 code points using the built-in rules.
8818                  * Go to another loop to finish processing upon encountering
8819                  * the first Latin1 code point.  We could do that in this loop
8820                  * as well, but the other way saves having to test if the swash
8821                  * has been loaded every time through the loop: extra space to
8822                  * save a test. */
8823                 while (hardcount < max && scan < loceol) {
8824                     if (UTF8_IS_INVARIANT(*scan)) {
8825                         if (! (to_complement ^ cBOOL(_generic_isCC((U8) *scan,
8826                                                                    classnum))))
8827                         {
8828                             break;
8829                         }
8830                         scan++;
8831                     }
8832                     else if (UTF8_IS_DOWNGRADEABLE_START(*scan)) {
8833                         if (! (to_complement
8834                               ^ cBOOL(_generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(*scan,
8835                                                                      *(scan + 1)),
8836                                                     classnum))))
8837                         {
8838                             break;
8839                         }
8840                         scan += 2;
8841                     }
8842                     else {
8843                         goto found_above_latin1;
8844                     }
8845 
8846                     hardcount++;
8847                 }
8848             }
8849             else {
8850                 /* For these character classes, the knowledge of how to handle
8851                  * every code point is compiled in to Perl via a macro.  This
8852                  * code is written for making the loops as tight as possible.
8853                  * It could be refactored to save space instead */
8854                 switch (classnum) {
8855                     case _CC_ENUM_SPACE:
8856                         while (hardcount < max
8857                                && scan < loceol
8858                                && (to_complement ^ cBOOL(isSPACE_utf8(scan))))
8859                         {
8860                             scan += UTF8SKIP(scan);
8861                             hardcount++;
8862                         }
8863                         break;
8864                     case _CC_ENUM_BLANK:
8865                         while (hardcount < max
8866                                && scan < loceol
8867                                && (to_complement ^ cBOOL(isBLANK_utf8(scan))))
8868                         {
8869                             scan += UTF8SKIP(scan);
8870                             hardcount++;
8871                         }
8872                         break;
8873                     case _CC_ENUM_XDIGIT:
8874                         while (hardcount < max
8875                                && scan < loceol
8876                                && (to_complement ^ cBOOL(isXDIGIT_utf8(scan))))
8877                         {
8878                             scan += UTF8SKIP(scan);
8879                             hardcount++;
8880                         }
8881                         break;
8882                     case _CC_ENUM_VERTSPACE:
8883                         while (hardcount < max
8884                                && scan < loceol
8885                                && (to_complement ^ cBOOL(isVERTWS_utf8(scan))))
8886                         {
8887                             scan += UTF8SKIP(scan);
8888                             hardcount++;
8889                         }
8890                         break;
8891                     case _CC_ENUM_CNTRL:
8892                         while (hardcount < max
8893                                && scan < loceol
8894                                && (to_complement ^ cBOOL(isCNTRL_utf8(scan))))
8895                         {
8896                             scan += UTF8SKIP(scan);
8897                             hardcount++;
8898                         }
8899                         break;
8900                     default:
8901                         Perl_croak(aTHX_ "panic: regrepeat() node %d='%s' has an unexpected character class '%d'", OP(p), PL_reg_name[OP(p)], classnum);
8902                 }
8903             }
8904 	}
8905         break;
8906 
8907       found_above_latin1:   /* Continuation of POSIXU and NPOSIXU */
8908 
8909         /* Load the swash if not already present */
8910         if (! PL_utf8_swash_ptrs[classnum]) {
8911             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
8912             PL_utf8_swash_ptrs[classnum] = _core_swash_init(
8913                                         "utf8",
8914                                         "",
8915                                         &PL_sv_undef, 1, 0,
8916                                         PL_XPosix_ptrs[classnum], &flags);
8917         }
8918 
8919         while (hardcount < max && scan < loceol
8920                && to_complement ^ cBOOL(_generic_utf8(
8921                                        classnum,
8922                                        scan,
8923                                        swash_fetch(PL_utf8_swash_ptrs[classnum],
8924                                                    (U8 *) scan,
8925                                                    TRUE))))
8926         {
8927             scan += UTF8SKIP(scan);
8928             hardcount++;
8929         }
8930         break;
8931 
8932     case LNBREAK:
8933         if (utf8_target) {
8934 	    while (hardcount < max && scan < loceol &&
8935                     (c=is_LNBREAK_utf8_safe(scan, loceol))) {
8936 		scan += c;
8937 		hardcount++;
8938 	    }
8939 	} else {
8940             /* LNBREAK can match one or two latin chars, which is ok, but we
8941              * have to use hardcount in this situation, and throw away the
8942              * adjustment to <loceol> done before the switch statement */
8943             loceol = reginfo->strend;
8944 	    while (scan < loceol && (c=is_LNBREAK_latin1_safe(scan, loceol))) {
8945 		scan+=c;
8946 		hardcount++;
8947 	    }
8948 	}
8949 	break;
8950 
8951     case BOUNDL:
8952     case NBOUNDL:
8953         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
8954         /* FALLTHROUGH */
8955     case BOUND:
8956     case BOUNDA:
8957     case BOUNDU:
8958     case EOS:
8959     case GPOS:
8960     case KEEPS:
8961     case NBOUND:
8962     case NBOUNDA:
8963     case NBOUNDU:
8964     case OPFAIL:
8965     case SBOL:
8966     case SEOL:
8967         /* These are all 0 width, so match right here or not at all. */
8968         break;
8969 
8970     default:
8971         Perl_croak(aTHX_ "panic: regrepeat() called with unrecognized node type %d='%s'", OP(p), PL_reg_name[OP(p)]);
8972         NOT_REACHED; /* NOTREACHED */
8973 
8974     }
8975 
8976     if (hardcount)
8977 	c = hardcount;
8978     else
8979 	c = scan - *startposp;
8980     *startposp = scan;
8981 
8982     DEBUG_r({
8983 	GET_RE_DEBUG_FLAGS_DECL;
8984 	DEBUG_EXECUTE_r({
8985 	    SV * const prop = sv_newmortal();
8986             regprop(prog, prop, p, reginfo, NULL);
8987             Perl_re_exec_indentf( aTHX_  "%s can match %"IVdf" times out of %"IVdf"...\n",
8988                         depth, SvPVX_const(prop),(IV)c,(IV)max);
8989 	});
8990     });
8991 
8992     return(c);
8993 }
8994 
8995 
8996 #if !defined(PERL_IN_XSUB_RE) || defined(PLUGGABLE_RE_EXTENSION)
8997 /*
8998 - regclass_swash - prepare the utf8 swash.  Wraps the shared core version to
8999 create a copy so that changes the caller makes won't change the shared one.
9000 If <altsvp> is non-null, will return NULL in it, for back-compat.
9001  */
9002 SV *
9003 Perl_regclass_swash(pTHX_ const regexp *prog, const regnode* node, bool doinit, SV** listsvp, SV **altsvp)
9004 {
9005     PERL_ARGS_ASSERT_REGCLASS_SWASH;
9006 
9007     if (altsvp) {
9008         *altsvp = NULL;
9009     }
9010 
9011     return newSVsv(_get_regclass_nonbitmap_data(prog, node, doinit, listsvp, NULL, NULL));
9012 }
9013 
9014 #endif /* !defined(PERL_IN_XSUB_RE) || defined(PLUGGABLE_RE_EXTENSION) */
9015 
9016 /*
9017  - reginclass - determine if a character falls into a character class
9018 
9019   n is the ANYOF-type regnode
9020   p is the target string
9021   p_end points to one byte beyond the end of the target string
9022   utf8_target tells whether p is in UTF-8.
9023 
9024   Returns true if matched; false otherwise.
9025 
9026   Note that this can be a synthetic start class, a combination of various
9027   nodes, so things you think might be mutually exclusive, such as locale,
9028   aren't.  It can match both locale and non-locale
9029 
9030  */
9031 
9032 STATIC bool
9033 S_reginclass(pTHX_ regexp * const prog, const regnode * const n, const U8* const p, const U8* const p_end, const bool utf8_target)
9034 {
9035     dVAR;
9036     const char flags = ANYOF_FLAGS(n);
9037     bool match = FALSE;
9038     UV c = *p;
9039 
9040     PERL_ARGS_ASSERT_REGINCLASS;
9041 
9042     /* If c is not already the code point, get it.  Note that
9043      * UTF8_IS_INVARIANT() works even if not in UTF-8 */
9044     if (! UTF8_IS_INVARIANT(c) && utf8_target) {
9045         STRLEN c_len = 0;
9046 	c = utf8n_to_uvchr(p, p_end - p, &c_len,
9047 		(UTF8_ALLOW_DEFAULT & UTF8_ALLOW_ANYUV)
9048 		| UTF8_ALLOW_FFFF | UTF8_CHECK_ONLY);
9049 		/* see [perl #37836] for UTF8_ALLOW_ANYUV; [perl #38293] for
9050 		 * UTF8_ALLOW_FFFF */
9051 	if (c_len == (STRLEN)-1)
9052 	    Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
9053         if (c > 255 && OP(n) == ANYOFL && ! ANYOFL_UTF8_LOCALE_REQD(flags)) {
9054             _CHECK_AND_OUTPUT_WIDE_LOCALE_CP_MSG(c);
9055         }
9056     }
9057 
9058     /* If this character is potentially in the bitmap, check it */
9059     if (c < NUM_ANYOF_CODE_POINTS) {
9060 	if (ANYOF_BITMAP_TEST(n, c))
9061 	    match = TRUE;
9062 	else if ((flags
9063                 & ANYOF_SHARED_d_MATCHES_ALL_NON_UTF8_NON_ASCII_non_d_WARN_SUPER)
9064                   && OP(n) == ANYOFD
9065 		  && ! utf8_target
9066 		  && ! isASCII(c))
9067 	{
9068 	    match = TRUE;
9069 	}
9070 	else if (flags & ANYOF_LOCALE_FLAGS) {
9071 	    if ((flags & ANYOFL_FOLD)
9072                 && c < 256
9073 		&& ANYOF_BITMAP_TEST(n, PL_fold_locale[c]))
9074             {
9075                 match = TRUE;
9076             }
9077             else if (ANYOF_POSIXL_TEST_ANY_SET(n)
9078                      && c < 256
9079             ) {
9080 
9081                 /* The data structure is arranged so bits 0, 2, 4, ... are set
9082                  * if the class includes the Posix character class given by
9083                  * bit/2; and 1, 3, 5, ... are set if the class includes the
9084                  * complemented Posix class given by int(bit/2).  So we loop
9085                  * through the bits, each time changing whether we complement
9086                  * the result or not.  Suppose for the sake of illustration
9087                  * that bits 0-3 mean respectively, \w, \W, \s, \S.  If bit 0
9088                  * is set, it means there is a match for this ANYOF node if the
9089                  * character is in the class given by the expression (0 / 2 = 0
9090                  * = \w).  If it is in that class, isFOO_lc() will return 1,
9091                  * and since 'to_complement' is 0, the result will stay TRUE,
9092                  * and we exit the loop.  Suppose instead that bit 0 is 0, but
9093                  * bit 1 is 1.  That means there is a match if the character
9094                  * matches \W.  We won't bother to call isFOO_lc() on bit 0,
9095                  * but will on bit 1.  On the second iteration 'to_complement'
9096                  * will be 1, so the exclusive or will reverse things, so we
9097                  * are testing for \W.  On the third iteration, 'to_complement'
9098                  * will be 0, and we would be testing for \s; the fourth
9099                  * iteration would test for \S, etc.
9100                  *
9101                  * Note that this code assumes that all the classes are closed
9102                  * under folding.  For example, if a character matches \w, then
9103                  * its fold does too; and vice versa.  This should be true for
9104                  * any well-behaved locale for all the currently defined Posix
9105                  * classes, except for :lower: and :upper:, which are handled
9106                  * by the pseudo-class :cased: which matches if either of the
9107                  * other two does.  To get rid of this assumption, an outer
9108                  * loop could be used below to iterate over both the source
9109                  * character, and its fold (if different) */
9110 
9111                 int count = 0;
9112                 int to_complement = 0;
9113 
9114                 while (count < ANYOF_MAX) {
9115                     if (ANYOF_POSIXL_TEST(n, count)
9116                         && to_complement ^ cBOOL(isFOO_lc(count/2, (U8) c)))
9117                     {
9118                         match = TRUE;
9119                         break;
9120                     }
9121                     count++;
9122                     to_complement ^= 1;
9123                 }
9124 	    }
9125 	}
9126     }
9127 
9128 
9129     /* If the bitmap didn't (or couldn't) match, and something outside the
9130      * bitmap could match, try that. */
9131     if (!match) {
9132 	if (c >= NUM_ANYOF_CODE_POINTS
9133             && (flags & ANYOF_MATCHES_ALL_ABOVE_BITMAP))
9134         {
9135 	    match = TRUE;	/* Everything above the bitmap matches */
9136 	}
9137             /* Here doesn't match everything above the bitmap.  If there is
9138              * some information available beyond the bitmap, we may find a
9139              * match in it.  If so, this is most likely because the code point
9140              * is outside the bitmap range.  But rarely, it could be because of
9141              * some other reason.  If so, various flags are set to indicate
9142              * this possibility.  On ANYOFD nodes, there may be matches that
9143              * happen only when the target string is UTF-8; or for other node
9144              * types, because runtime lookup is needed, regardless of the
9145              * UTF-8ness of the target string.  Finally, under /il, there may
9146              * be some matches only possible if the locale is a UTF-8 one. */
9147 	else if (    ARG(n) != ANYOF_ONLY_HAS_BITMAP
9148                  && (   c >= NUM_ANYOF_CODE_POINTS
9149                      || (   (flags & ANYOF_SHARED_d_UPPER_LATIN1_UTF8_STRING_MATCHES_non_d_RUNTIME_USER_PROP)
9150                          && (   UNLIKELY(OP(n) != ANYOFD)
9151                              || (utf8_target && ! isASCII_uni(c)
9152 #                               if NUM_ANYOF_CODE_POINTS > 256
9153                                                                  && c < 256
9154 #                               endif
9155                                 )))
9156                      || (   ANYOFL_SOME_FOLDS_ONLY_IN_UTF8_LOCALE(flags)
9157                          && IN_UTF8_CTYPE_LOCALE)))
9158         {
9159             SV* only_utf8_locale = NULL;
9160 	    SV * const sw = _get_regclass_nonbitmap_data(prog, n, TRUE, 0,
9161                                                        &only_utf8_locale, NULL);
9162 	    if (sw) {
9163                 U8 utf8_buffer[2];
9164 		U8 * utf8_p;
9165 		if (utf8_target) {
9166 		    utf8_p = (U8 *) p;
9167 		} else { /* Convert to utf8 */
9168 		    utf8_p = utf8_buffer;
9169                     append_utf8_from_native_byte(*p, &utf8_p);
9170 		    utf8_p = utf8_buffer;
9171 		}
9172 
9173 		if (swash_fetch(sw, utf8_p, TRUE)) {
9174 		    match = TRUE;
9175                 }
9176 	    }
9177             if (! match && only_utf8_locale && IN_UTF8_CTYPE_LOCALE) {
9178                 match = _invlist_contains_cp(only_utf8_locale, c);
9179             }
9180 	}
9181 
9182         if (UNICODE_IS_SUPER(c)
9183             && (flags
9184                & ANYOF_SHARED_d_MATCHES_ALL_NON_UTF8_NON_ASCII_non_d_WARN_SUPER)
9185             && OP(n) != ANYOFD
9186             && ckWARN_d(WARN_NON_UNICODE))
9187         {
9188             Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
9189                 "Matched non-Unicode code point 0x%04"UVXf" against Unicode property; may not be portable", c);
9190         }
9191     }
9192 
9193 #if ANYOF_INVERT != 1
9194     /* Depending on compiler optimization cBOOL takes time, so if don't have to
9195      * use it, don't */
9196 #   error ANYOF_INVERT needs to be set to 1, or guarded with cBOOL below,
9197 #endif
9198 
9199     /* The xor complements the return if to invert: 1^1 = 0, 1^0 = 1 */
9200     return (flags & ANYOF_INVERT) ^ match;
9201 }
9202 
9203 STATIC U8 *
9204 S_reghop3(U8 *s, SSize_t off, const U8* lim)
9205 {
9206     /* return the position 'off' UTF-8 characters away from 's', forward if
9207      * 'off' >= 0, backwards if negative.  But don't go outside of position
9208      * 'lim', which better be < s  if off < 0 */
9209 
9210     PERL_ARGS_ASSERT_REGHOP3;
9211 
9212     if (off >= 0) {
9213 	while (off-- && s < lim) {
9214 	    /* XXX could check well-formedness here */
9215 	    s += UTF8SKIP(s);
9216 	}
9217     }
9218     else {
9219         while (off++ && s > lim) {
9220             s--;
9221             if (UTF8_IS_CONTINUED(*s)) {
9222                 while (s > lim && UTF8_IS_CONTINUATION(*s))
9223                     s--;
9224                 if (! UTF8_IS_START(*s)) {
9225                     Perl_croak_nocontext("Malformed UTF-8 character (fatal)");
9226                 }
9227 	    }
9228             /* XXX could check well-formedness here */
9229 	}
9230     }
9231     return s;
9232 }
9233 
9234 STATIC U8 *
9235 S_reghop4(U8 *s, SSize_t off, const U8* llim, const U8* rlim)
9236 {
9237     PERL_ARGS_ASSERT_REGHOP4;
9238 
9239     if (off >= 0) {
9240         while (off-- && s < rlim) {
9241             /* XXX could check well-formedness here */
9242             s += UTF8SKIP(s);
9243         }
9244     }
9245     else {
9246         while (off++ && s > llim) {
9247             s--;
9248             if (UTF8_IS_CONTINUED(*s)) {
9249                 while (s > llim && UTF8_IS_CONTINUATION(*s))
9250                     s--;
9251                 if (! UTF8_IS_START(*s)) {
9252                     Perl_croak_nocontext("Malformed UTF-8 character (fatal)");
9253                 }
9254             }
9255             /* XXX could check well-formedness here */
9256         }
9257     }
9258     return s;
9259 }
9260 
9261 /* like reghop3, but returns NULL on overrun, rather than returning last
9262  * char pos */
9263 
9264 STATIC U8 *
9265 S_reghopmaybe3(U8* s, SSize_t off, const U8* lim)
9266 {
9267     PERL_ARGS_ASSERT_REGHOPMAYBE3;
9268 
9269     if (off >= 0) {
9270 	while (off-- && s < lim) {
9271 	    /* XXX could check well-formedness here */
9272 	    s += UTF8SKIP(s);
9273 	}
9274 	if (off >= 0)
9275 	    return NULL;
9276     }
9277     else {
9278         while (off++ && s > lim) {
9279             s--;
9280             if (UTF8_IS_CONTINUED(*s)) {
9281                 while (s > lim && UTF8_IS_CONTINUATION(*s))
9282                     s--;
9283                 if (! UTF8_IS_START(*s)) {
9284                     Perl_croak_nocontext("Malformed UTF-8 character (fatal)");
9285                 }
9286 	    }
9287             /* XXX could check well-formedness here */
9288 	}
9289 	if (off <= 0)
9290 	    return NULL;
9291     }
9292     return s;
9293 }
9294 
9295 
9296 /* when executing a regex that may have (?{}), extra stuff needs setting
9297    up that will be visible to the called code, even before the current
9298    match has finished. In particular:
9299 
9300    * $_ is localised to the SV currently being matched;
9301    * pos($_) is created if necessary, ready to be updated on each call-out
9302      to code;
9303    * a fake PMOP is created that can be set to PL_curpm (normally PL_curpm
9304      isn't set until the current pattern is successfully finished), so that
9305      $1 etc of the match-so-far can be seen;
9306    * save the old values of subbeg etc of the current regex, and  set then
9307      to the current string (again, this is normally only done at the end
9308      of execution)
9309 */
9310 
9311 static void
9312 S_setup_eval_state(pTHX_ regmatch_info *const reginfo)
9313 {
9314     MAGIC *mg;
9315     regexp *const rex = ReANY(reginfo->prog);
9316     regmatch_info_aux_eval *eval_state = reginfo->info_aux_eval;
9317 
9318     eval_state->rex = rex;
9319 
9320     if (reginfo->sv) {
9321         /* Make $_ available to executed code. */
9322         if (reginfo->sv != DEFSV) {
9323             SAVE_DEFSV;
9324             DEFSV_set(reginfo->sv);
9325         }
9326 
9327         if (!(mg = mg_find_mglob(reginfo->sv))) {
9328             /* prepare for quick setting of pos */
9329             mg = sv_magicext_mglob(reginfo->sv);
9330             mg->mg_len = -1;
9331         }
9332         eval_state->pos_magic = mg;
9333         eval_state->pos       = mg->mg_len;
9334         eval_state->pos_flags = mg->mg_flags;
9335     }
9336     else
9337         eval_state->pos_magic = NULL;
9338 
9339     if (!PL_reg_curpm) {
9340         /* PL_reg_curpm is a fake PMOP that we can attach the current
9341          * regex to and point PL_curpm at, so that $1 et al are visible
9342          * within a /(?{})/. It's just allocated once per interpreter the
9343          * first time its needed */
9344         Newxz(PL_reg_curpm, 1, PMOP);
9345 #ifdef USE_ITHREADS
9346         {
9347             SV* const repointer = &PL_sv_undef;
9348             /* this regexp is also owned by the new PL_reg_curpm, which
9349                will try to free it.  */
9350             av_push(PL_regex_padav, repointer);
9351             PL_reg_curpm->op_pmoffset = av_tindex(PL_regex_padav);
9352             PL_regex_pad = AvARRAY(PL_regex_padav);
9353         }
9354 #endif
9355     }
9356     SET_reg_curpm(reginfo->prog);
9357     eval_state->curpm = PL_curpm;
9358     PL_curpm = PL_reg_curpm;
9359     if (RXp_MATCH_COPIED(rex)) {
9360         /*  Here is a serious problem: we cannot rewrite subbeg,
9361             since it may be needed if this match fails.  Thus
9362             $` inside (?{}) could fail... */
9363         eval_state->subbeg     = rex->subbeg;
9364         eval_state->sublen     = rex->sublen;
9365         eval_state->suboffset  = rex->suboffset;
9366         eval_state->subcoffset = rex->subcoffset;
9367 #ifdef PERL_ANY_COW
9368         eval_state->saved_copy = rex->saved_copy;
9369 #endif
9370         RXp_MATCH_COPIED_off(rex);
9371     }
9372     else
9373         eval_state->subbeg = NULL;
9374     rex->subbeg = (char *)reginfo->strbeg;
9375     rex->suboffset = 0;
9376     rex->subcoffset = 0;
9377     rex->sublen = reginfo->strend - reginfo->strbeg;
9378 }
9379 
9380 
9381 /* destructor to clear up regmatch_info_aux and regmatch_info_aux_eval */
9382 
9383 static void
9384 S_cleanup_regmatch_info_aux(pTHX_ void *arg)
9385 {
9386     regmatch_info_aux *aux = (regmatch_info_aux *) arg;
9387     regmatch_info_aux_eval *eval_state =  aux->info_aux_eval;
9388     regmatch_slab *s;
9389 
9390     Safefree(aux->poscache);
9391 
9392     if (eval_state) {
9393 
9394         /* undo the effects of S_setup_eval_state() */
9395 
9396         if (eval_state->subbeg) {
9397             regexp * const rex = eval_state->rex;
9398             rex->subbeg     = eval_state->subbeg;
9399             rex->sublen     = eval_state->sublen;
9400             rex->suboffset  = eval_state->suboffset;
9401             rex->subcoffset = eval_state->subcoffset;
9402 #ifdef PERL_ANY_COW
9403             rex->saved_copy = eval_state->saved_copy;
9404 #endif
9405             RXp_MATCH_COPIED_on(rex);
9406         }
9407         if (eval_state->pos_magic)
9408         {
9409             eval_state->pos_magic->mg_len = eval_state->pos;
9410             eval_state->pos_magic->mg_flags =
9411                  (eval_state->pos_magic->mg_flags & ~MGf_BYTES)
9412                | (eval_state->pos_flags & MGf_BYTES);
9413         }
9414 
9415         PL_curpm = eval_state->curpm;
9416     }
9417 
9418     PL_regmatch_state = aux->old_regmatch_state;
9419     PL_regmatch_slab  = aux->old_regmatch_slab;
9420 
9421     /* free all slabs above current one - this must be the last action
9422      * of this function, as aux and eval_state are allocated within
9423      * slabs and may be freed here */
9424 
9425     s = PL_regmatch_slab->next;
9426     if (s) {
9427         PL_regmatch_slab->next = NULL;
9428         while (s) {
9429             regmatch_slab * const osl = s;
9430             s = s->next;
9431             Safefree(osl);
9432         }
9433     }
9434 }
9435 
9436 
9437 STATIC void
9438 S_to_utf8_substr(pTHX_ regexp *prog)
9439 {
9440     /* Converts substr fields in prog from bytes to UTF-8, calling fbm_compile
9441      * on the converted value */
9442 
9443     int i = 1;
9444 
9445     PERL_ARGS_ASSERT_TO_UTF8_SUBSTR;
9446 
9447     do {
9448 	if (prog->substrs->data[i].substr
9449 	    && !prog->substrs->data[i].utf8_substr) {
9450 	    SV* const sv = newSVsv(prog->substrs->data[i].substr);
9451 	    prog->substrs->data[i].utf8_substr = sv;
9452 	    sv_utf8_upgrade(sv);
9453 	    if (SvVALID(prog->substrs->data[i].substr)) {
9454 		if (SvTAIL(prog->substrs->data[i].substr)) {
9455 		    /* Trim the trailing \n that fbm_compile added last
9456 		       time.  */
9457 		    SvCUR_set(sv, SvCUR(sv) - 1);
9458 		    /* Whilst this makes the SV technically "invalid" (as its
9459 		       buffer is no longer followed by "\0") when fbm_compile()
9460 		       adds the "\n" back, a "\0" is restored.  */
9461 		    fbm_compile(sv, FBMcf_TAIL);
9462 		} else
9463 		    fbm_compile(sv, 0);
9464 	    }
9465 	    if (prog->substrs->data[i].substr == prog->check_substr)
9466 		prog->check_utf8 = sv;
9467 	}
9468     } while (i--);
9469 }
9470 
9471 STATIC bool
9472 S_to_byte_substr(pTHX_ regexp *prog)
9473 {
9474     /* Converts substr fields in prog from UTF-8 to bytes, calling fbm_compile
9475      * on the converted value; returns FALSE if can't be converted. */
9476 
9477     int i = 1;
9478 
9479     PERL_ARGS_ASSERT_TO_BYTE_SUBSTR;
9480 
9481     do {
9482 	if (prog->substrs->data[i].utf8_substr
9483 	    && !prog->substrs->data[i].substr) {
9484 	    SV* sv = newSVsv(prog->substrs->data[i].utf8_substr);
9485 	    if (! sv_utf8_downgrade(sv, TRUE)) {
9486                 return FALSE;
9487             }
9488             if (SvVALID(prog->substrs->data[i].utf8_substr)) {
9489                 if (SvTAIL(prog->substrs->data[i].utf8_substr)) {
9490                     /* Trim the trailing \n that fbm_compile added last
9491                         time.  */
9492                     SvCUR_set(sv, SvCUR(sv) - 1);
9493                     fbm_compile(sv, FBMcf_TAIL);
9494                 } else
9495                     fbm_compile(sv, 0);
9496             }
9497 	    prog->substrs->data[i].substr = sv;
9498 	    if (prog->substrs->data[i].utf8_substr == prog->check_utf8)
9499 		prog->check_substr = sv;
9500 	}
9501     } while (i--);
9502 
9503     return TRUE;
9504 }
9505 
9506 /*
9507  * ex: set ts=8 sts=4 sw=4 et:
9508  */
9509