xref: /openbsd-src/gnu/usr.bin/perl/regexec.c (revision 50b7afb2c2c0993b0894d4e34bf857cb13ed9c80)
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 /* At least one required character in the target string is expressible only in
41  * UTF-8. */
42 static const char* const non_utf8_target_but_utf8_required
43                 = "Can't match, because target string needs to be in UTF-8\n";
44 
45 #define NON_UTF8_TARGET_BUT_UTF8_REQUIRED(target) STMT_START { \
46     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%s", non_utf8_target_but_utf8_required));\
47     goto target; \
48 } STMT_END
49 
50 /*
51  * pregcomp and pregexec -- regsub and regerror are not used in perl
52  *
53  *	Copyright (c) 1986 by University of Toronto.
54  *	Written by Henry Spencer.  Not derived from licensed software.
55  *
56  *	Permission is granted to anyone to use this software for any
57  *	purpose on any computer system, and to redistribute it freely,
58  *	subject to the following restrictions:
59  *
60  *	1. The author is not responsible for the consequences of use of
61  *		this software, no matter how awful, even if they arise
62  *		from defects in it.
63  *
64  *	2. The origin of this software must not be misrepresented, either
65  *		by explicit claim or by omission.
66  *
67  *	3. Altered versions must be plainly marked as such, and must not
68  *		be misrepresented as being the original software.
69  *
70  ****    Alterations to Henry's code are...
71  ****
72  ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
73  ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
74  ****    by Larry Wall and others
75  ****
76  ****    You may distribute under the terms of either the GNU General Public
77  ****    License or the Artistic License, as specified in the README file.
78  *
79  * Beware that some of this code is subtly aware of the way operator
80  * precedence is structured in regular expressions.  Serious changes in
81  * regular-expression syntax might require a total rethink.
82  */
83 #include "EXTERN.h"
84 #define PERL_IN_REGEXEC_C
85 #include "perl.h"
86 
87 #ifdef PERL_IN_XSUB_RE
88 #  include "re_comp.h"
89 #else
90 #  include "regcomp.h"
91 #endif
92 
93 #include "inline_invlist.c"
94 #include "unicode_constants.h"
95 
96 #define HAS_NONLATIN1_FOLD_CLOSURE(i) _HAS_NONLATIN1_FOLD_CLOSURE_ONLY_FOR_USE_BY_REGCOMP_DOT_C_AND_REGEXEC_DOT_C(i)
97 
98 #ifndef STATIC
99 #define	STATIC	static
100 #endif
101 
102 /* Valid for non-utf8 strings: avoids the reginclass
103  * call if there are no complications: i.e., if everything matchable is
104  * straight forward in the bitmap */
105 #define REGINCLASS(prog,p,c)  (ANYOF_FLAGS(p) ? reginclass(prog,p,c,0)   \
106 					      : ANYOF_BITMAP_TEST(p,*(c)))
107 
108 /*
109  * Forwards.
110  */
111 
112 #define CHR_SVLEN(sv) (utf8_target ? sv_len_utf8(sv) : SvCUR(sv))
113 #define CHR_DIST(a,b) (PL_reg_match_utf8 ? utf8_distance(a,b) : a - b)
114 
115 #define HOPc(pos,off) \
116 	(char *)(PL_reg_match_utf8 \
117 	    ? reghop3((U8*)pos, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr)) \
118 	    : (U8*)(pos + off))
119 #define HOPBACKc(pos, off) \
120 	(char*)(PL_reg_match_utf8\
121 	    ? reghopmaybe3((U8*)pos, -off, (U8*)PL_bostr) \
122 	    : (pos - off >= PL_bostr)		\
123 		? (U8*)pos - off		\
124 		: NULL)
125 
126 #define HOP3(pos,off,lim) (PL_reg_match_utf8 ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
127 #define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
128 
129 
130 #define NEXTCHR_EOS -10 /* nextchr has fallen off the end */
131 #define NEXTCHR_IS_EOS (nextchr < 0)
132 
133 #define SET_nextchr \
134     nextchr = ((locinput < PL_regeol) ? UCHARAT(locinput) : NEXTCHR_EOS)
135 
136 #define SET_locinput(p) \
137     locinput = (p);  \
138     SET_nextchr
139 
140 
141 #define LOAD_UTF8_CHARCLASS(swash_ptr, property_name) STMT_START {            \
142         if (!swash_ptr) {                                                     \
143             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;                       \
144             swash_ptr = _core_swash_init("utf8", property_name, &PL_sv_undef, \
145                                          1, 0, NULL, &flags);                 \
146             assert(swash_ptr);                                                \
147         }                                                                     \
148     } STMT_END
149 
150 /* If in debug mode, we test that a known character properly matches */
151 #ifdef DEBUGGING
152 #   define LOAD_UTF8_CHARCLASS_DEBUG_TEST(swash_ptr,                          \
153                                           property_name,                      \
154                                           utf8_char_in_property)              \
155         LOAD_UTF8_CHARCLASS(swash_ptr, property_name);                        \
156         assert(swash_fetch(swash_ptr, (U8 *) utf8_char_in_property, TRUE));
157 #else
158 #   define LOAD_UTF8_CHARCLASS_DEBUG_TEST(swash_ptr,                          \
159                                           property_name,                      \
160                                           utf8_char_in_property)              \
161         LOAD_UTF8_CHARCLASS(swash_ptr, property_name)
162 #endif
163 
164 #define LOAD_UTF8_CHARCLASS_ALNUM() LOAD_UTF8_CHARCLASS_DEBUG_TEST(           \
165                                         PL_utf8_swash_ptrs[_CC_WORDCHAR],     \
166                                         swash_property_names[_CC_WORDCHAR],   \
167                                         GREEK_SMALL_LETTER_IOTA_UTF8)
168 
169 #define LOAD_UTF8_CHARCLASS_GCB()  /* Grapheme cluster boundaries */          \
170     STMT_START {                                                              \
171 	LOAD_UTF8_CHARCLASS_DEBUG_TEST(PL_utf8_X_regular_begin,               \
172                                        "_X_regular_begin",                    \
173                                        GREEK_SMALL_LETTER_IOTA_UTF8);         \
174 	LOAD_UTF8_CHARCLASS_DEBUG_TEST(PL_utf8_X_extend,                      \
175                                        "_X_extend",                           \
176                                        COMBINING_GRAVE_ACCENT_UTF8);          \
177     } STMT_END
178 
179 #define PLACEHOLDER	/* Something for the preprocessor to grab onto */
180 /* TODO: Combine JUMPABLE and HAS_TEXT to cache OP(rn) */
181 
182 /* for use after a quantifier and before an EXACT-like node -- japhy */
183 /* it would be nice to rework regcomp.sym to generate this stuff. sigh
184  *
185  * NOTE that *nothing* that affects backtracking should be in here, specifically
186  * VERBS must NOT be included. JUMPABLE is used to determine  if we can ignore a
187  * node that is in between two EXACT like nodes when ascertaining what the required
188  * "follow" character is. This should probably be moved to regex compile time
189  * although it may be done at run time beause of the REF possibility - more
190  * investigation required. -- demerphq
191 */
192 #define JUMPABLE(rn) (      \
193     OP(rn) == OPEN ||       \
194     (OP(rn) == CLOSE && (!cur_eval || cur_eval->u.eval.close_paren != ARG(rn))) || \
195     OP(rn) == EVAL ||   \
196     OP(rn) == SUSPEND || OP(rn) == IFMATCH || \
197     OP(rn) == PLUS || OP(rn) == MINMOD || \
198     OP(rn) == KEEPS || \
199     (PL_regkind[OP(rn)] == CURLY && ARG1(rn) > 0) \
200 )
201 #define IS_EXACT(rn) (PL_regkind[OP(rn)] == EXACT)
202 
203 #define HAS_TEXT(rn) ( IS_EXACT(rn) || PL_regkind[OP(rn)] == REF )
204 
205 #if 0
206 /* Currently these are only used when PL_regkind[OP(rn)] == EXACT so
207    we don't need this definition. */
208 #define IS_TEXT(rn)   ( OP(rn)==EXACT   || OP(rn)==REF   || OP(rn)==NREF   )
209 #define IS_TEXTF(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFU_SS || OP(rn)==EXACTFU_TRICKYFOLD || OP(rn)==EXACTFA || OP(rn)==EXACTF || OP(rn)==REFF  || OP(rn)==NREFF )
210 #define IS_TEXTFL(rn) ( OP(rn)==EXACTFL || OP(rn)==REFFL || OP(rn)==NREFFL )
211 
212 #else
213 /* ... so we use this as its faster. */
214 #define IS_TEXT(rn)   ( OP(rn)==EXACT   )
215 #define IS_TEXTFU(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFU_SS || OP(rn)==EXACTFU_TRICKYFOLD || OP(rn) == EXACTFA)
216 #define IS_TEXTF(rn)  ( OP(rn)==EXACTF  )
217 #define IS_TEXTFL(rn) ( OP(rn)==EXACTFL )
218 
219 #endif
220 
221 /*
222   Search for mandatory following text node; for lookahead, the text must
223   follow but for lookbehind (rn->flags != 0) we skip to the next step.
224 */
225 #define FIND_NEXT_IMPT(rn) STMT_START { \
226     while (JUMPABLE(rn)) { \
227 	const OPCODE type = OP(rn); \
228 	if (type == SUSPEND || PL_regkind[type] == CURLY) \
229 	    rn = NEXTOPER(NEXTOPER(rn)); \
230 	else if (type == PLUS) \
231 	    rn = NEXTOPER(rn); \
232 	else if (type == IFMATCH) \
233 	    rn = (rn->flags == 0) ? NEXTOPER(NEXTOPER(rn)) : rn + ARG(rn); \
234 	else rn += NEXT_OFF(rn); \
235     } \
236 } STMT_END
237 
238 /* These constants are for finding GCB=LV and GCB=LVT in the CLUMP regnode.
239  * These are for the pre-composed Hangul syllables, which are all in a
240  * contiguous block and arranged there in such a way so as to facilitate
241  * alorithmic determination of their characteristics.  As such, they don't need
242  * a swash, but can be determined by simple arithmetic.  Almost all are
243  * GCB=LVT, but every 28th one is a GCB=LV */
244 #define SBASE 0xAC00    /* Start of block */
245 #define SCount 11172    /* Length of block */
246 #define TCount 28
247 
248 static void restore_pos(pTHX_ void *arg);
249 
250 #define REGCP_PAREN_ELEMS 3
251 #define REGCP_OTHER_ELEMS 3
252 #define REGCP_FRAME_ELEMS 1
253 /* REGCP_FRAME_ELEMS are not part of the REGCP_OTHER_ELEMS and
254  * are needed for the regexp context stack bookkeeping. */
255 
256 STATIC CHECKPOINT
257 S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
258 {
259     dVAR;
260     const int retval = PL_savestack_ix;
261     const int paren_elems_to_push =
262                 (maxopenparen - parenfloor) * REGCP_PAREN_ELEMS;
263     const UV total_elems = paren_elems_to_push + REGCP_OTHER_ELEMS;
264     const UV elems_shifted = total_elems << SAVE_TIGHT_SHIFT;
265     I32 p;
266     GET_RE_DEBUG_FLAGS_DECL;
267 
268     PERL_ARGS_ASSERT_REGCPPUSH;
269 
270     if (paren_elems_to_push < 0)
271 	Perl_croak(aTHX_ "panic: paren_elems_to_push, %i < 0",
272 		   paren_elems_to_push);
273 
274     if ((elems_shifted >> SAVE_TIGHT_SHIFT) != total_elems)
275 	Perl_croak(aTHX_ "panic: paren_elems_to_push offset %"UVuf
276 		   " out of range (%lu-%ld)",
277 		   total_elems,
278                    (unsigned long)maxopenparen,
279                    (long)parenfloor);
280 
281     SSGROW(total_elems + REGCP_FRAME_ELEMS);
282 
283     DEBUG_BUFFERS_r(
284 	if ((int)maxopenparen > (int)parenfloor)
285 	    PerlIO_printf(Perl_debug_log,
286 		"rex=0x%"UVxf" offs=0x%"UVxf": saving capture indices:\n",
287 		PTR2UV(rex),
288 		PTR2UV(rex->offs)
289 	    );
290     );
291     for (p = parenfloor+1; p <= (I32)maxopenparen;  p++) {
292 /* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
293 	SSPUSHINT(rex->offs[p].end);
294 	SSPUSHINT(rex->offs[p].start);
295 	SSPUSHINT(rex->offs[p].start_tmp);
296 	DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
297 	    "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"\n",
298 	    (UV)p,
299 	    (IV)rex->offs[p].start,
300 	    (IV)rex->offs[p].start_tmp,
301 	    (IV)rex->offs[p].end
302 	));
303     }
304 /* REGCP_OTHER_ELEMS are pushed in any case, parentheses or no. */
305     SSPUSHINT(maxopenparen);
306     SSPUSHINT(rex->lastparen);
307     SSPUSHINT(rex->lastcloseparen);
308     SSPUSHUV(SAVEt_REGCONTEXT | elems_shifted); /* Magic cookie. */
309 
310     return retval;
311 }
312 
313 /* These are needed since we do not localize EVAL nodes: */
314 #define REGCP_SET(cp)                                           \
315     DEBUG_STATE_r(                                              \
316             PerlIO_printf(Perl_debug_log,		        \
317 	        "  Setting an EVAL scope, savestack=%"IVdf"\n",	\
318 	        (IV)PL_savestack_ix));                          \
319     cp = PL_savestack_ix
320 
321 #define REGCP_UNWIND(cp)                                        \
322     DEBUG_STATE_r(                                              \
323         if (cp != PL_savestack_ix) 		                \
324     	    PerlIO_printf(Perl_debug_log,		        \
325 		"  Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
326 	        (IV)(cp), (IV)PL_savestack_ix));                \
327     regcpblow(cp)
328 
329 #define UNWIND_PAREN(lp, lcp)               \
330     for (n = rex->lastparen; n > lp; n--)   \
331         rex->offs[n].end = -1;              \
332     rex->lastparen = n;                     \
333     rex->lastcloseparen = lcp;
334 
335 
336 STATIC void
337 S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
338 {
339     dVAR;
340     UV i;
341     U32 paren;
342     GET_RE_DEBUG_FLAGS_DECL;
343 
344     PERL_ARGS_ASSERT_REGCPPOP;
345 
346     /* Pop REGCP_OTHER_ELEMS before the parentheses loop starts. */
347     i = SSPOPUV;
348     assert((i & SAVE_MASK) == SAVEt_REGCONTEXT); /* Check that the magic cookie is there. */
349     i >>= SAVE_TIGHT_SHIFT; /* Parentheses elements to pop. */
350     rex->lastcloseparen = SSPOPINT;
351     rex->lastparen = SSPOPINT;
352     *maxopenparen_p = SSPOPINT;
353 
354     i -= REGCP_OTHER_ELEMS;
355     /* Now restore the parentheses context. */
356     DEBUG_BUFFERS_r(
357 	if (i || rex->lastparen + 1 <= rex->nparens)
358 	    PerlIO_printf(Perl_debug_log,
359 		"rex=0x%"UVxf" offs=0x%"UVxf": restoring capture indices to:\n",
360 		PTR2UV(rex),
361 		PTR2UV(rex->offs)
362 	    );
363     );
364     paren = *maxopenparen_p;
365     for ( ; i > 0; i -= REGCP_PAREN_ELEMS) {
366 	I32 tmps;
367 	rex->offs[paren].start_tmp = SSPOPINT;
368 	rex->offs[paren].start = SSPOPINT;
369 	tmps = SSPOPINT;
370 	if (paren <= rex->lastparen)
371 	    rex->offs[paren].end = tmps;
372 	DEBUG_BUFFERS_r( PerlIO_printf(Perl_debug_log,
373 	    "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"%s\n",
374 	    (UV)paren,
375 	    (IV)rex->offs[paren].start,
376 	    (IV)rex->offs[paren].start_tmp,
377 	    (IV)rex->offs[paren].end,
378 	    (paren > rex->lastparen ? "(skipped)" : ""));
379 	);
380 	paren--;
381     }
382 #if 1
383     /* It would seem that the similar code in regtry()
384      * already takes care of this, and in fact it is in
385      * a better location to since this code can #if 0-ed out
386      * but the code in regtry() is needed or otherwise tests
387      * requiring null fields (pat.t#187 and split.t#{13,14}
388      * (as of patchlevel 7877)  will fail.  Then again,
389      * this code seems to be necessary or otherwise
390      * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
391      * --jhi updated by dapm */
392     for (i = rex->lastparen + 1; i <= rex->nparens; i++) {
393 	if (i > *maxopenparen_p)
394 	    rex->offs[i].start = -1;
395 	rex->offs[i].end = -1;
396 	DEBUG_BUFFERS_r( PerlIO_printf(Perl_debug_log,
397 	    "    \\%"UVuf": %s   ..-1 undeffing\n",
398 	    (UV)i,
399 	    (i > *maxopenparen_p) ? "-1" : "  "
400 	));
401     }
402 #endif
403 }
404 
405 /* restore the parens and associated vars at savestack position ix,
406  * but without popping the stack */
407 
408 STATIC void
409 S_regcp_restore(pTHX_ regexp *rex, I32 ix, U32 *maxopenparen_p)
410 {
411     I32 tmpix = PL_savestack_ix;
412     PL_savestack_ix = ix;
413     regcppop(rex, maxopenparen_p);
414     PL_savestack_ix = tmpix;
415 }
416 
417 #define regcpblow(cp) LEAVE_SCOPE(cp)	/* Ignores regcppush()ed data. */
418 
419 STATIC bool
420 S_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
421 {
422     /* Returns a boolean as to whether or not 'character' is a member of the
423      * Posix character class given by 'classnum' that should be equivalent to a
424      * value in the typedef '_char_class_number'.
425      *
426      * Ideally this could be replaced by a just an array of function pointers
427      * to the C library functions that implement the macros this calls.
428      * However, to compile, the precise function signatures are required, and
429      * these may vary from platform to to platform.  To avoid having to figure
430      * out what those all are on each platform, I (khw) am using this method,
431      * which adds an extra layer of function call overhead (unless the C
432      * optimizer strips it away).  But we don't particularly care about
433      * performance with locales anyway. */
434 
435     switch ((_char_class_number) classnum) {
436         case _CC_ENUM_ALPHANUMERIC: return isALPHANUMERIC_LC(character);
437         case _CC_ENUM_ALPHA:     return isALPHA_LC(character);
438         case _CC_ENUM_ASCII:     return isASCII_LC(character);
439         case _CC_ENUM_BLANK:     return isBLANK_LC(character);
440         case _CC_ENUM_CASED:     return isLOWER_LC(character)
441                                         || isUPPER_LC(character);
442         case _CC_ENUM_CNTRL:     return isCNTRL_LC(character);
443         case _CC_ENUM_DIGIT:     return isDIGIT_LC(character);
444         case _CC_ENUM_GRAPH:     return isGRAPH_LC(character);
445         case _CC_ENUM_LOWER:     return isLOWER_LC(character);
446         case _CC_ENUM_PRINT:     return isPRINT_LC(character);
447         case _CC_ENUM_PSXSPC:    return isPSXSPC_LC(character);
448         case _CC_ENUM_PUNCT:     return isPUNCT_LC(character);
449         case _CC_ENUM_SPACE:     return isSPACE_LC(character);
450         case _CC_ENUM_UPPER:     return isUPPER_LC(character);
451         case _CC_ENUM_WORDCHAR:  return isWORDCHAR_LC(character);
452         case _CC_ENUM_XDIGIT:    return isXDIGIT_LC(character);
453         default:    /* VERTSPACE should never occur in locales */
454             Perl_croak(aTHX_ "panic: isFOO_lc() has an unexpected character class '%d'", classnum);
455     }
456 
457     assert(0); /* NOTREACHED */
458     return FALSE;
459 }
460 
461 STATIC bool
462 S_isFOO_utf8_lc(pTHX_ const U8 classnum, const U8* character)
463 {
464     /* Returns a boolean as to whether or not the (well-formed) UTF-8-encoded
465      * 'character' is a member of the Posix character class given by 'classnum'
466      * that should be equivalent to a value in the typedef
467      * '_char_class_number'.
468      *
469      * This just calls isFOO_lc on the code point for the character if it is in
470      * the range 0-255.  Outside that range, all characters avoid Unicode
471      * rules, ignoring any locale.  So use the Unicode function if this class
472      * requires a swash, and use the Unicode macro otherwise. */
473 
474     PERL_ARGS_ASSERT_ISFOO_UTF8_LC;
475 
476     if (UTF8_IS_INVARIANT(*character)) {
477         return isFOO_lc(classnum, *character);
478     }
479     else if (UTF8_IS_DOWNGRADEABLE_START(*character)) {
480         return isFOO_lc(classnum,
481                         TWO_BYTE_UTF8_TO_UNI(*character, *(character + 1)));
482     }
483 
484     if (classnum < _FIRST_NON_SWASH_CC) {
485 
486         /* Initialize the swash unless done already */
487         if (! PL_utf8_swash_ptrs[classnum]) {
488             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
489             PL_utf8_swash_ptrs[classnum] = _core_swash_init("utf8",
490                 swash_property_names[classnum], &PL_sv_undef, 1, 0, NULL, &flags);
491         }
492 
493         return cBOOL(swash_fetch(PL_utf8_swash_ptrs[classnum], (U8 *)
494                                  character,
495                                  TRUE /* is UTF */ ));
496     }
497 
498     switch ((_char_class_number) classnum) {
499         case _CC_ENUM_SPACE:
500         case _CC_ENUM_PSXSPC:    return is_XPERLSPACE_high(character);
501 
502         case _CC_ENUM_BLANK:     return is_HORIZWS_high(character);
503         case _CC_ENUM_XDIGIT:    return is_XDIGIT_high(character);
504         case _CC_ENUM_VERTSPACE: return is_VERTWS_high(character);
505         default:                 return 0;  /* Things like CNTRL are always
506                                                below 256 */
507     }
508 
509     assert(0); /* NOTREACHED */
510     return FALSE;
511 }
512 
513 /*
514  * pregexec and friends
515  */
516 
517 #ifndef PERL_IN_XSUB_RE
518 /*
519  - pregexec - match a regexp against a string
520  */
521 I32
522 Perl_pregexec(pTHX_ REGEXP * const prog, char* stringarg, char *strend,
523 	 char *strbeg, I32 minend, SV *screamer, U32 nosave)
524 /* stringarg: the point in the string at which to begin matching */
525 /* strend:    pointer to null at end of string */
526 /* strbeg:    real beginning of string */
527 /* minend:    end of match must be >= minend bytes after stringarg. */
528 /* screamer:  SV being matched: only used for utf8 flag, pos() etc; string
529  *            itself is accessed via the pointers above */
530 /* nosave:    For optimizations. */
531 {
532     PERL_ARGS_ASSERT_PREGEXEC;
533 
534     return
535 	regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL,
536 		      nosave ? 0 : REXEC_COPY_STR);
537 }
538 #endif
539 
540 /*
541  * Need to implement the following flags for reg_anch:
542  *
543  * USE_INTUIT_NOML		- Useful to call re_intuit_start() first
544  * USE_INTUIT_ML
545  * INTUIT_AUTORITATIVE_NOML	- Can trust a positive answer
546  * INTUIT_AUTORITATIVE_ML
547  * INTUIT_ONCE_NOML		- Intuit can match in one location only.
548  * INTUIT_ONCE_ML
549  *
550  * Another flag for this function: SECOND_TIME (so that float substrs
551  * with giant delta may be not rechecked).
552  */
553 
554 /* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */
555 
556 /* If SCREAM, then SvPVX_const(sv) should be compatible with strpos and strend.
557    Otherwise, only SvCUR(sv) is used to get strbeg. */
558 
559 /* XXXX We assume that strpos is strbeg unless sv. */
560 
561 /* XXXX Some places assume that there is a fixed substring.
562 	An update may be needed if optimizer marks as "INTUITable"
563 	RExen without fixed substrings.  Similarly, it is assumed that
564 	lengths of all the strings are no more than minlen, thus they
565 	cannot come from lookahead.
566 	(Or minlen should take into account lookahead.)
567   NOTE: Some of this comment is not correct. minlen does now take account
568   of lookahead/behind. Further research is required. -- demerphq
569 
570 */
571 
572 /* A failure to find a constant substring means that there is no need to make
573    an expensive call to REx engine, thus we celebrate a failure.  Similarly,
574    finding a substring too deep into the string means that fewer calls to
575    regtry() should be needed.
576 
577    REx compiler's optimizer found 4 possible hints:
578 	a) Anchored substring;
579 	b) Fixed substring;
580 	c) Whether we are anchored (beginning-of-line or \G);
581 	d) First node (of those at offset 0) which may distinguish positions;
582    We use a)b)d) and multiline-part of c), and try to find a position in the
583    string which does not contradict any of them.
584  */
585 
586 /* Most of decisions we do here should have been done at compile time.
587    The nodes of the REx which we used for the search should have been
588    deleted from the finite automaton. */
589 
590 char *
591 Perl_re_intuit_start(pTHX_ REGEXP * const rx, SV *sv, char *strpos,
592 		     char *strend, const U32 flags, re_scream_pos_data *data)
593 {
594     dVAR;
595     struct regexp *const prog = ReANY(rx);
596     I32 start_shift = 0;
597     /* Should be nonnegative! */
598     I32 end_shift   = 0;
599     char *s;
600     SV *check;
601     char *strbeg;
602     char *t;
603     const bool utf8_target = (sv && SvUTF8(sv)) ? 1 : 0; /* if no sv we have to assume bytes */
604     I32 ml_anch;
605     char *other_last = NULL;	/* other substr checked before this */
606     char *check_at = NULL;		/* check substr found at this pos */
607     char *checked_upto = NULL;          /* how far into the string we have already checked using find_byclass*/
608     const I32 multiline = prog->extflags & RXf_PMf_MULTILINE;
609     RXi_GET_DECL(prog,progi);
610     bool is_utf8_pat;
611 #ifdef DEBUGGING
612     const char * const i_strpos = strpos;
613 #endif
614     GET_RE_DEBUG_FLAGS_DECL;
615 
616     PERL_ARGS_ASSERT_RE_INTUIT_START;
617     PERL_UNUSED_ARG(flags);
618     PERL_UNUSED_ARG(data);
619 
620     RX_MATCH_UTF8_set(rx,utf8_target);
621 
622     is_utf8_pat = cBOOL(RX_UTF8(rx));
623 
624     DEBUG_EXECUTE_r(
625         debug_start_match(rx, utf8_target, strpos, strend,
626             sv ? "Guessing start of match in sv for"
627                : "Guessing start of match in string for");
628 	      );
629 
630     /* CHR_DIST() would be more correct here but it makes things slow. */
631     if (prog->minlen > strend - strpos) {
632 	DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
633 			      "String too short... [re_intuit_start]\n"));
634 	goto fail;
635     }
636 
637     /* XXX we need to pass strbeg as a separate arg: the following is
638      * guesswork and can be wrong... */
639     if (sv && SvPOK(sv)) {
640         char * p   = SvPVX(sv);
641         STRLEN cur = SvCUR(sv);
642         if (p <= strpos && strpos < p + cur) {
643             strbeg = p;
644             assert(p <= strend && strend <= p + cur);
645         }
646         else
647             strbeg = strend - cur;
648     }
649     else
650         strbeg = strpos;
651 
652     PL_regeol = strend;
653     if (utf8_target) {
654 	if (!prog->check_utf8 && prog->check_substr)
655 	    to_utf8_substr(prog);
656 	check = prog->check_utf8;
657     } else {
658 	if (!prog->check_substr && prog->check_utf8) {
659 	    if (! to_byte_substr(prog)) {
660                 NON_UTF8_TARGET_BUT_UTF8_REQUIRED(fail);
661             }
662         }
663 	check = prog->check_substr;
664     }
665     if (prog->extflags & RXf_ANCH) {	/* Match at beg-of-str or after \n */
666 	ml_anch = !( (prog->extflags & RXf_ANCH_SINGLE)
667 		     || ( (prog->extflags & RXf_ANCH_BOL)
668 			  && !multiline ) );	/* Check after \n? */
669 
670 	if (!ml_anch) {
671 	  if ( !(prog->extflags & RXf_ANCH_GPOS) /* Checked by the caller */
672 		&& !(prog->intflags & PREGf_IMPLICIT) /* not a real BOL */
673 	       /* SvCUR is not set on references: SvRV and SvPVX_const overlap */
674 	       && sv && !SvROK(sv)
675 	       && (strpos != strbeg)) {
676 	      DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
677 	      goto fail;
678 	  }
679 	  if (prog->check_offset_min == prog->check_offset_max
680               && !(prog->extflags & RXf_CANY_SEEN)
681               && ! multiline)   /* /m can cause \n's to match that aren't
682                                    accounted for in the string max length.
683                                    See [perl #115242] */
684           {
685 	    /* Substring at constant offset from beg-of-str... */
686 	    I32 slen;
687 
688 	    s = HOP3c(strpos, prog->check_offset_min, strend);
689 
690 	    if (SvTAIL(check)) {
691 		slen = SvCUR(check);	/* >= 1 */
692 
693 		if ( strend - s > slen || strend - s < slen - 1
694 		     || (strend - s == slen && strend[-1] != '\n')) {
695 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String too long...\n"));
696 		    goto fail_finish;
697 		}
698 		/* Now should match s[0..slen-2] */
699 		slen--;
700 		if (slen && (*SvPVX_const(check) != *s
701 			     || (slen > 1
702 				 && memNE(SvPVX_const(check), s, slen)))) {
703 		  report_neq:
704 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
705 		    goto fail_finish;
706 		}
707 	    }
708 	    else if (*SvPVX_const(check) != *s
709 		     || ((slen = SvCUR(check)) > 1
710 			 && memNE(SvPVX_const(check), s, slen)))
711 		goto report_neq;
712 	    check_at = s;
713 	    goto success_at_start;
714 	  }
715 	}
716 	/* Match is anchored, but substr is not anchored wrt beg-of-str. */
717 	s = strpos;
718 	start_shift = prog->check_offset_min; /* okay to underestimate on CC */
719 	end_shift = prog->check_end_shift;
720 
721 	if (!ml_anch) {
722 	    const I32 end = prog->check_offset_max + CHR_SVLEN(check)
723 					 - (SvTAIL(check) != 0);
724 	    const I32 eshift = CHR_DIST((U8*)strend, (U8*)s) - end;
725 
726 	    if (end_shift < eshift)
727 		end_shift = eshift;
728 	}
729     }
730     else {				/* Can match at random position */
731 	ml_anch = 0;
732 	s = strpos;
733 	start_shift = prog->check_offset_min;  /* okay to underestimate on CC */
734 	end_shift = prog->check_end_shift;
735 
736 	/* end shift should be non negative here */
737     }
738 
739 #ifdef QDEBUGGING	/* 7/99: reports of failure (with the older version) */
740     if (end_shift < 0)
741 	Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
742 		   (IV)end_shift, RX_PRECOMP(prog));
743 #endif
744 
745   restart:
746     /* Find a possible match in the region s..strend by looking for
747        the "check" substring in the region corrected by start/end_shift. */
748 
749     {
750         I32 srch_start_shift = start_shift;
751         I32 srch_end_shift = end_shift;
752         U8* start_point;
753         U8* end_point;
754         if (srch_start_shift < 0 && strbeg - s > srch_start_shift) {
755 	    srch_end_shift -= ((strbeg - s) - srch_start_shift);
756 	    srch_start_shift = strbeg - s;
757 	}
758     DEBUG_OPTIMISE_MORE_r({
759         PerlIO_printf(Perl_debug_log, "Check offset min: %"IVdf" Start shift: %"IVdf" End shift %"IVdf" Real End Shift: %"IVdf"\n",
760             (IV)prog->check_offset_min,
761             (IV)srch_start_shift,
762             (IV)srch_end_shift,
763             (IV)prog->check_end_shift);
764     });
765 
766         if (prog->extflags & RXf_CANY_SEEN) {
767             start_point= (U8*)(s + srch_start_shift);
768             end_point= (U8*)(strend - srch_end_shift);
769         } else {
770 	    start_point= HOP3(s, srch_start_shift, srch_start_shift < 0 ? strbeg : strend);
771             end_point= HOP3(strend, -srch_end_shift, strbeg);
772 	}
773 	DEBUG_OPTIMISE_MORE_r({
774             PerlIO_printf(Perl_debug_log, "fbm_instr len=%d str=<%.*s>\n",
775                 (int)(end_point - start_point),
776                 (int)(end_point - start_point) > 20 ? 20 : (int)(end_point - start_point),
777                 start_point);
778         });
779 
780 	s = fbm_instr( start_point, end_point,
781 		      check, multiline ? FBMrf_MULTILINE : 0);
782     }
783     /* Update the count-of-usability, remove useless subpatterns,
784 	unshift s.  */
785 
786     DEBUG_EXECUTE_r({
787         RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
788             SvPVX_const(check), RE_SV_DUMPLEN(check), 30);
789         PerlIO_printf(Perl_debug_log, "%s %s substr %s%s%s",
790 			  (s ? "Found" : "Did not find"),
791 	    (check == (utf8_target ? prog->anchored_utf8 : prog->anchored_substr)
792 	        ? "anchored" : "floating"),
793 	    quoted,
794 	    RE_SV_TAIL(check),
795 	    (s ? " at offset " : "...\n") );
796     });
797 
798     if (!s)
799 	goto fail_finish;
800     /* Finish the diagnostic message */
801     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - i_strpos)) );
802 
803     /* XXX dmq: first branch is for positive lookbehind...
804        Our check string is offset from the beginning of the pattern.
805        So we need to do any stclass tests offset forward from that
806        point. I think. :-(
807      */
808 
809 
810 
811     check_at=s;
812 
813 
814     /* Got a candidate.  Check MBOL anchoring, and the *other* substr.
815        Start with the other substr.
816        XXXX no SCREAM optimization yet - and a very coarse implementation
817        XXXX /ttx+/ results in anchored="ttx", floating="x".  floating will
818 		*always* match.  Probably should be marked during compile...
819        Probably it is right to do no SCREAM here...
820      */
821 
822     if (utf8_target ? (prog->float_utf8 && prog->anchored_utf8)
823                 : (prog->float_substr && prog->anchored_substr))
824     {
825 	/* Take into account the "other" substring. */
826 	/* XXXX May be hopelessly wrong for UTF... */
827 	if (!other_last)
828 	    other_last = strpos;
829 	if (check == (utf8_target ? prog->float_utf8 : prog->float_substr)) {
830 	  do_other_anchored:
831 	    {
832 		char * const last = HOP3c(s, -start_shift, strbeg);
833 		char *last1, *last2;
834 		char * const saved_s = s;
835 		SV* must;
836 
837 		t = s - prog->check_offset_max;
838 		if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
839 		    && (!utf8_target
840 			|| ((t = (char*)reghopmaybe3((U8*)s, -(prog->check_offset_max), (U8*)strpos))
841 			    && t > strpos)))
842 		    NOOP;
843 		else
844 		    t = strpos;
845 		t = HOP3c(t, prog->anchored_offset, strend);
846 		if (t < other_last)	/* These positions already checked */
847 		    t = other_last;
848 		last2 = last1 = HOP3c(strend, -prog->minlen, strbeg);
849 		if (last < last1)
850 		    last1 = last;
851                 /* XXXX It is not documented what units *_offsets are in.
852                    We assume bytes, but this is clearly wrong.
853                    Meaning this code needs to be carefully reviewed for errors.
854                    dmq.
855                   */
856 
857 		/* On end-of-str: see comment below. */
858 		must = utf8_target ? prog->anchored_utf8 : prog->anchored_substr;
859 		if (must == &PL_sv_undef) {
860 		    s = (char*)NULL;
861 		    DEBUG_r(must = prog->anchored_utf8);	/* for debug */
862 		}
863 		else
864 		    s = fbm_instr(
865 			(unsigned char*)t,
866 			HOP3(HOP3(last1, prog->anchored_offset, strend)
867 				+ SvCUR(must), -(SvTAIL(must)!=0), strbeg),
868 			must,
869 			multiline ? FBMrf_MULTILINE : 0
870 		    );
871                 DEBUG_EXECUTE_r({
872                     RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
873                         SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
874                     PerlIO_printf(Perl_debug_log, "%s anchored substr %s%s",
875 			(s ? "Found" : "Contradicts"),
876                         quoted, RE_SV_TAIL(must));
877                 });
878 
879 
880 		if (!s) {
881 		    if (last1 >= last2) {
882 			DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
883 						", giving up...\n"));
884 			goto fail_finish;
885 		    }
886 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
887 			", trying floating at offset %ld...\n",
888 			(long)(HOP3c(saved_s, 1, strend) - i_strpos)));
889 		    other_last = HOP3c(last1, prog->anchored_offset+1, strend);
890 		    s = HOP3c(last, 1, strend);
891 		    goto restart;
892 		}
893 		else {
894 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
895 			  (long)(s - i_strpos)));
896 		    t = HOP3c(s, -prog->anchored_offset, strbeg);
897 		    other_last = HOP3c(s, 1, strend);
898 		    s = saved_s;
899 		    if (t == strpos)
900 			goto try_at_start;
901 		    goto try_at_offset;
902 		}
903 	    }
904 	}
905 	else {		/* Take into account the floating substring. */
906 	    char *last, *last1;
907 	    char * const saved_s = s;
908 	    SV* must;
909 
910 	    t = HOP3c(s, -start_shift, strbeg);
911 	    last1 = last =
912 		HOP3c(strend, -prog->minlen + prog->float_min_offset, strbeg);
913 	    if (CHR_DIST((U8*)last, (U8*)t) > prog->float_max_offset)
914 		last = HOP3c(t, prog->float_max_offset, strend);
915 	    s = HOP3c(t, prog->float_min_offset, strend);
916 	    if (s < other_last)
917 		s = other_last;
918  /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
919 	    must = utf8_target ? prog->float_utf8 : prog->float_substr;
920 	    /* fbm_instr() takes into account exact value of end-of-str
921 	       if the check is SvTAIL(ed).  Since false positives are OK,
922 	       and end-of-str is not later than strend we are OK. */
923 	    if (must == &PL_sv_undef) {
924 		s = (char*)NULL;
925 		DEBUG_r(must = prog->float_utf8);	/* for debug message */
926 	    }
927 	    else
928 		s = fbm_instr((unsigned char*)s,
929 			      (unsigned char*)last + SvCUR(must)
930 				  - (SvTAIL(must)!=0),
931 			      must, multiline ? FBMrf_MULTILINE : 0);
932 	    DEBUG_EXECUTE_r({
933 	        RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
934 	            SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
935 	        PerlIO_printf(Perl_debug_log, "%s floating substr %s%s",
936 		    (s ? "Found" : "Contradicts"),
937 		    quoted, RE_SV_TAIL(must));
938             });
939 	    if (!s) {
940 		if (last1 == last) {
941 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
942 					    ", giving up...\n"));
943 		    goto fail_finish;
944 		}
945 		DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
946 		    ", trying anchored starting at offset %ld...\n",
947 		    (long)(saved_s + 1 - i_strpos)));
948 		other_last = last;
949 		s = HOP3c(t, 1, strend);
950 		goto restart;
951 	    }
952 	    else {
953 		DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
954 		      (long)(s - i_strpos)));
955 		other_last = s; /* Fix this later. --Hugo */
956 		s = saved_s;
957 		if (t == strpos)
958 		    goto try_at_start;
959 		goto try_at_offset;
960 	    }
961 	}
962     }
963 
964 
965     t= (char*)HOP3( s, -prog->check_offset_max, (prog->check_offset_max<0) ? strend : strpos);
966 
967     DEBUG_OPTIMISE_MORE_r(
968         PerlIO_printf(Perl_debug_log,
969             "Check offset min:%"IVdf" max:%"IVdf" S:%"IVdf" t:%"IVdf" D:%"IVdf" end:%"IVdf"\n",
970             (IV)prog->check_offset_min,
971             (IV)prog->check_offset_max,
972             (IV)(s-strpos),
973             (IV)(t-strpos),
974             (IV)(t-s),
975             (IV)(strend-strpos)
976         )
977     );
978 
979     if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
980         && (!utf8_target
981 	    || ((t = (char*)reghopmaybe3((U8*)s, -prog->check_offset_max, (U8*) ((prog->check_offset_max<0) ? strend : strpos)))
982 		 && t > strpos)))
983     {
984 	/* Fixed substring is found far enough so that the match
985 	   cannot start at strpos. */
986       try_at_offset:
987 	if (ml_anch && t[-1] != '\n') {
988 	    /* Eventually fbm_*() should handle this, but often
989 	       anchored_offset is not 0, so this check will not be wasted. */
990 	    /* XXXX In the code below we prefer to look for "^" even in
991 	       presence of anchored substrings.  And we search even
992 	       beyond the found float position.  These pessimizations
993 	       are historical artefacts only.  */
994 	  find_anchor:
995 	    while (t < strend - prog->minlen) {
996 		if (*t == '\n') {
997 		    if (t < check_at - prog->check_offset_min) {
998 			if (utf8_target ? prog->anchored_utf8 : prog->anchored_substr) {
999 			    /* Since we moved from the found position,
1000 			       we definitely contradict the found anchored
1001 			       substr.  Due to the above check we do not
1002 			       contradict "check" substr.
1003 			       Thus we can arrive here only if check substr
1004 			       is float.  Redo checking for "other"=="fixed".
1005 			     */
1006 			    strpos = t + 1;
1007 			    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld, rescanning for anchored from offset %ld...\n",
1008 				PL_colors[0], PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
1009 			    goto do_other_anchored;
1010 			}
1011 			/* We don't contradict the found floating substring. */
1012 			/* XXXX Why not check for STCLASS? */
1013 			s = t + 1;
1014 			DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
1015 			    PL_colors[0], PL_colors[1], (long)(s - i_strpos)));
1016 			goto set_useful;
1017 		    }
1018 		    /* Position contradicts check-string */
1019 		    /* XXXX probably better to look for check-string
1020 		       than for "\n", so one should lower the limit for t? */
1021 		    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting lookup for check-string at offset %ld...\n",
1022 			PL_colors[0], PL_colors[1], (long)(t + 1 - i_strpos)));
1023 		    other_last = strpos = s = t + 1;
1024 		    goto restart;
1025 		}
1026 		t++;
1027 	    }
1028 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n",
1029 			PL_colors[0], PL_colors[1]));
1030 	    goto fail_finish;
1031 	}
1032 	else {
1033 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Starting position does not contradict /%s^%s/m...\n",
1034 			PL_colors[0], PL_colors[1]));
1035 	}
1036 	s = t;
1037       set_useful:
1038 	++BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr);	/* hooray/5 */
1039     }
1040     else {
1041 	/* The found string does not prohibit matching at strpos,
1042 	   - no optimization of calling REx engine can be performed,
1043 	   unless it was an MBOL and we are not after MBOL,
1044 	   or a future STCLASS check will fail this. */
1045       try_at_start:
1046 	/* Even in this situation we may use MBOL flag if strpos is offset
1047 	   wrt the start of the string. */
1048 	if (ml_anch && sv && !SvROK(sv)	/* See prev comment on SvROK */
1049 	    && (strpos != strbeg) && strpos[-1] != '\n'
1050 	    /* May be due to an implicit anchor of m{.*foo}  */
1051 	    && !(prog->intflags & PREGf_IMPLICIT))
1052 	{
1053 	    t = strpos;
1054 	    goto find_anchor;
1055 	}
1056 	DEBUG_EXECUTE_r( if (ml_anch)
1057 	    PerlIO_printf(Perl_debug_log, "Position at offset %ld does not contradict /%s^%s/m...\n",
1058 			  (long)(strpos - i_strpos), PL_colors[0], PL_colors[1]);
1059 	);
1060       success_at_start:
1061 	if (!(prog->intflags & PREGf_NAUGHTY)	/* XXXX If strpos moved? */
1062 	    && (utf8_target ? (
1063 		prog->check_utf8		/* Could be deleted already */
1064 		&& --BmUSEFUL(prog->check_utf8) < 0
1065 		&& (prog->check_utf8 == prog->float_utf8)
1066 	    ) : (
1067 		prog->check_substr		/* Could be deleted already */
1068 		&& --BmUSEFUL(prog->check_substr) < 0
1069 		&& (prog->check_substr == prog->float_substr)
1070 	    )))
1071 	{
1072 	    /* If flags & SOMETHING - do not do it many times on the same match */
1073 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "... Disabling check substring...\n"));
1074 	    /* XXX Does the destruction order has to change with utf8_target? */
1075 	    SvREFCNT_dec(utf8_target ? prog->check_utf8 : prog->check_substr);
1076 	    SvREFCNT_dec(utf8_target ? prog->check_substr : prog->check_utf8);
1077 	    prog->check_substr = prog->check_utf8 = NULL;	/* disable */
1078 	    prog->float_substr = prog->float_utf8 = NULL;	/* clear */
1079 	    check = NULL;			/* abort */
1080 	    s = strpos;
1081 	    /* XXXX If the check string was an implicit check MBOL, then we need to unset the relevant flag
1082 		    see http://bugs.activestate.com/show_bug.cgi?id=87173 */
1083 	    if (prog->intflags & PREGf_IMPLICIT)
1084 		prog->extflags &= ~RXf_ANCH_MBOL;
1085 	    /* XXXX This is a remnant of the old implementation.  It
1086 	            looks wasteful, since now INTUIT can use many
1087 	            other heuristics. */
1088 	    prog->extflags &= ~RXf_USE_INTUIT;
1089 	    /* XXXX What other flags might need to be cleared in this branch? */
1090 	}
1091 	else
1092 	    s = strpos;
1093     }
1094 
1095     /* Last resort... */
1096     /* XXXX BmUSEFUL already changed, maybe multiple change is meaningful... */
1097     /* trie stclasses are too expensive to use here, we are better off to
1098        leave it to regmatch itself */
1099     if (progi->regstclass && PL_regkind[OP(progi->regstclass)]!=TRIE) {
1100 	/* minlen == 0 is possible if regstclass is \b or \B,
1101 	   and the fixed substr is ''$.
1102 	   Since minlen is already taken into account, s+1 is before strend;
1103 	   accidentally, minlen >= 1 guaranties no false positives at s + 1
1104 	   even for \b or \B.  But (minlen? 1 : 0) below assumes that
1105 	   regstclass does not come from lookahead...  */
1106 	/* If regstclass takes bytelength more than 1: If charlength==1, OK.
1107 	   This leaves EXACTF-ish only, which are dealt with in find_byclass().  */
1108         const U8* const str = (U8*)STRING(progi->regstclass);
1109         const int cl_l = (PL_regkind[OP(progi->regstclass)] == EXACT
1110 		    ? CHR_DIST(str+STR_LEN(progi->regstclass), str)
1111 		    : 1);
1112 	char * endpos;
1113 	if (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
1114             endpos= HOP3c(s, (prog->minlen ? cl_l : 0), strend);
1115         else if (prog->float_substr || prog->float_utf8)
1116 	    endpos= HOP3c(HOP3c(check_at, -start_shift, strbeg), cl_l, strend);
1117         else
1118             endpos= strend;
1119 
1120         if (checked_upto < s)
1121            checked_upto = s;
1122         DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %"IVdf" s: %"IVdf" endpos: %"IVdf" checked_upto: %"IVdf"\n",
1123                                       (IV)start_shift, (IV)(check_at - strbeg), (IV)(s - strbeg), (IV)(endpos - strbeg), (IV)(checked_upto- strbeg)));
1124 
1125 	t = s;
1126         s = find_byclass(prog, progi->regstclass, checked_upto, endpos,
1127                             NULL, is_utf8_pat);
1128 	if (s) {
1129 	    checked_upto = s;
1130 	} else {
1131 #ifdef DEBUGGING
1132 	    const char *what = NULL;
1133 #endif
1134 	    if (endpos == strend) {
1135 		DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1136 				"Could not match STCLASS...\n") );
1137 		goto fail;
1138 	    }
1139 	    DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1140 				   "This position contradicts STCLASS...\n") );
1141 	    if ((prog->extflags & RXf_ANCH) && !ml_anch)
1142 		goto fail;
1143 	    checked_upto = HOPBACKc(endpos, start_shift);
1144 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %"IVdf" endpos: %"IVdf" checked_upto: %"IVdf"\n",
1145                                       (IV)start_shift, (IV)(check_at - strbeg), (IV)(endpos - strbeg), (IV)(checked_upto- strbeg)));
1146 	    /* Contradict one of substrings */
1147 	    if (prog->anchored_substr || prog->anchored_utf8) {
1148 		if ((utf8_target ? prog->anchored_utf8 : prog->anchored_substr) == check) {
1149 		    DEBUG_EXECUTE_r( what = "anchored" );
1150 		  hop_and_restart:
1151 		    s = HOP3c(t, 1, strend);
1152 		    if (s + start_shift + end_shift > strend) {
1153 			/* XXXX Should be taken into account earlier? */
1154 			DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1155 					       "Could not match STCLASS...\n") );
1156 			goto fail;
1157 		    }
1158 		    if (!check)
1159 			goto giveup;
1160 		    DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1161 				"Looking for %s substr starting at offset %ld...\n",
1162 				 what, (long)(s + start_shift - i_strpos)) );
1163 		    goto restart;
1164 		}
1165 		/* Have both, check_string is floating */
1166 		if (t + start_shift >= check_at) /* Contradicts floating=check */
1167 		    goto retry_floating_check;
1168 		/* Recheck anchored substring, but not floating... */
1169 		s = check_at;
1170 		if (!check)
1171 		    goto giveup;
1172 		DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1173 			  "Looking for anchored substr starting at offset %ld...\n",
1174 			  (long)(other_last - i_strpos)) );
1175 		goto do_other_anchored;
1176 	    }
1177 	    /* Another way we could have checked stclass at the
1178                current position only: */
1179 	    if (ml_anch) {
1180 		s = t = t + 1;
1181 		if (!check)
1182 		    goto giveup;
1183 		DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
1184 			  "Looking for /%s^%s/m starting at offset %ld...\n",
1185 			  PL_colors[0], PL_colors[1], (long)(t - i_strpos)) );
1186 		goto try_at_offset;
1187 	    }
1188 	    if (!(utf8_target ? prog->float_utf8 : prog->float_substr))	/* Could have been deleted */
1189 		goto fail;
1190 	    /* Check is floating substring. */
1191 	  retry_floating_check:
1192 	    t = check_at - start_shift;
1193 	    DEBUG_EXECUTE_r( what = "floating" );
1194 	    goto hop_and_restart;
1195 	}
1196 	if (t != s) {
1197             DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
1198 			"By STCLASS: moving %ld --> %ld\n",
1199                                   (long)(t - i_strpos), (long)(s - i_strpos))
1200                    );
1201         }
1202         else {
1203             DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
1204                                   "Does not contradict STCLASS...\n");
1205                    );
1206         }
1207     }
1208   giveup:
1209     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%s%s:%s match at offset %ld\n",
1210 			  PL_colors[4], (check ? "Guessed" : "Giving up"),
1211 			  PL_colors[5], (long)(s - i_strpos)) );
1212     return s;
1213 
1214   fail_finish:				/* Substring not found */
1215     if (prog->check_substr || prog->check_utf8)		/* could be removed already */
1216 	BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr) += 5; /* hooray */
1217   fail:
1218     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n",
1219 			  PL_colors[4], PL_colors[5]));
1220     return NULL;
1221 }
1222 
1223 #define DECL_TRIE_TYPE(scan) \
1224     const enum { trie_plain, trie_utf8, trie_utf8_fold, trie_latin_utf8_fold } \
1225                     trie_type = ((scan->flags == EXACT) \
1226                               ? (utf8_target ? trie_utf8 : trie_plain) \
1227                               : (utf8_target ? trie_utf8_fold : trie_latin_utf8_fold))
1228 
1229 #define REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, uscan, len, uvc, charid, foldlen, foldbuf, uniflags) \
1230 STMT_START {                               \
1231     STRLEN skiplen;                                                                 \
1232     switch (trie_type) {                                                            \
1233     case trie_utf8_fold:                                                            \
1234         if ( foldlen>0 ) {                                                          \
1235             uvc = utf8n_to_uvuni( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
1236             foldlen -= len;                                                         \
1237             uscan += len;                                                           \
1238             len=0;                                                                  \
1239         } else {                                                                    \
1240             uvc = to_utf8_fold( (const U8*) uc, foldbuf, &foldlen );                \
1241             len = UTF8SKIP(uc);                                                     \
1242             skiplen = UNISKIP( uvc );                                               \
1243             foldlen -= skiplen;                                                     \
1244             uscan = foldbuf + skiplen;                                              \
1245         }                                                                           \
1246         break;                                                                      \
1247     case trie_latin_utf8_fold:                                                      \
1248         if ( foldlen>0 ) {                                                          \
1249             uvc = utf8n_to_uvuni( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
1250             foldlen -= len;                                                         \
1251             uscan += len;                                                           \
1252             len=0;                                                                  \
1253         } else {                                                                    \
1254             len = 1;                                                                \
1255             uvc = _to_fold_latin1( (U8) *uc, foldbuf, &foldlen, 1);                 \
1256             skiplen = UNISKIP( uvc );                                               \
1257             foldlen -= skiplen;                                                     \
1258             uscan = foldbuf + skiplen;                                              \
1259         }                                                                           \
1260         break;                                                                      \
1261     case trie_utf8:                                                                 \
1262         uvc = utf8n_to_uvuni( (const U8*) uc, UTF8_MAXLEN, &len, uniflags );        \
1263         break;                                                                      \
1264     case trie_plain:                                                                \
1265         uvc = (UV)*uc;                                                              \
1266         len = 1;                                                                    \
1267     }                                                                               \
1268     if (uvc < 256) {                                                                \
1269         charid = trie->charmap[ uvc ];                                              \
1270     }                                                                               \
1271     else {                                                                          \
1272         charid = 0;                                                                 \
1273         if (widecharmap) {                                                          \
1274             SV** const svpp = hv_fetch(widecharmap,                                 \
1275                         (char*)&uvc, sizeof(UV), 0);                                \
1276             if (svpp)                                                               \
1277                 charid = (U16)SvIV(*svpp);                                          \
1278         }                                                                           \
1279     }                                                                               \
1280 } STMT_END
1281 
1282 #define REXEC_FBC_EXACTISH_SCAN(CoNd)                     \
1283 STMT_START {                                              \
1284     while (s <= e) {                                      \
1285 	if ( (CoNd)                                       \
1286 	     && (ln == 1 || folder(s, pat_string, ln))    \
1287 	     && (!reginfo || regtry(reginfo, &s)) )       \
1288 	    goto got_it;                                  \
1289 	s++;                                              \
1290     }                                                     \
1291 } STMT_END
1292 
1293 #define REXEC_FBC_UTF8_SCAN(CoDe)                     \
1294 STMT_START {                                          \
1295     while (s < strend) {                              \
1296 	CoDe                                          \
1297 	s += UTF8SKIP(s);                             \
1298     }                                                 \
1299 } STMT_END
1300 
1301 #define REXEC_FBC_SCAN(CoDe)                          \
1302 STMT_START {                                          \
1303     while (s < strend) {                              \
1304 	CoDe                                          \
1305 	s++;                                          \
1306     }                                                 \
1307 } STMT_END
1308 
1309 #define REXEC_FBC_UTF8_CLASS_SCAN(CoNd)               \
1310 REXEC_FBC_UTF8_SCAN(                                  \
1311     if (CoNd) {                                       \
1312 	if (tmp && (!reginfo || regtry(reginfo, &s))) \
1313 	    goto got_it;                              \
1314 	else                                          \
1315 	    tmp = doevery;                            \
1316     }                                                 \
1317     else                                              \
1318 	tmp = 1;                                      \
1319 )
1320 
1321 #define REXEC_FBC_CLASS_SCAN(CoNd)                    \
1322 REXEC_FBC_SCAN(                                       \
1323     if (CoNd) {                                       \
1324 	if (tmp && (!reginfo || regtry(reginfo, &s)))  \
1325 	    goto got_it;                              \
1326 	else                                          \
1327 	    tmp = doevery;                            \
1328     }                                                 \
1329     else                                              \
1330 	tmp = 1;                                      \
1331 )
1332 
1333 #define REXEC_FBC_TRYIT               \
1334 if ((!reginfo || regtry(reginfo, &s))) \
1335     goto got_it
1336 
1337 #define REXEC_FBC_CSCAN(CoNdUtF8,CoNd)                         \
1338     if (utf8_target) {                                             \
1339 	REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
1340     }                                                          \
1341     else {                                                     \
1342 	REXEC_FBC_CLASS_SCAN(CoNd);                            \
1343     }
1344 
1345 #define DUMP_EXEC_POS(li,s,doutf8) \
1346     dump_exec_pos(li,s,(PL_regeol),(PL_bostr),(PL_reg_starttry),doutf8)
1347 
1348 
1349 #define UTF8_NOLOAD(TEST_NON_UTF8, IF_SUCCESS, IF_FAIL) \
1350 	tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';                         \
1351 	tmp = TEST_NON_UTF8(tmp);                                              \
1352 	REXEC_FBC_UTF8_SCAN(                                                   \
1353 	    if (tmp == ! TEST_NON_UTF8((U8) *s)) { \
1354 		tmp = !tmp;                                                    \
1355 		IF_SUCCESS;                                                    \
1356 	    }                                                                  \
1357 	    else {                                                             \
1358 		IF_FAIL;                                                       \
1359 	    }                                                                  \
1360 	);                                                                     \
1361 
1362 #define UTF8_LOAD(TeSt1_UtF8, TeSt2_UtF8, IF_SUCCESS, IF_FAIL) \
1363 	if (s == PL_bostr) {                                                   \
1364 	    tmp = '\n';                                                        \
1365 	}                                                                      \
1366 	else {                                                                 \
1367 	    U8 * const r = reghop3((U8*)s, -1, (U8*)PL_bostr);                 \
1368 	    tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, UTF8_ALLOW_DEFAULT);       \
1369 	}                                                                      \
1370 	tmp = TeSt1_UtF8;                                                      \
1371 	LOAD_UTF8_CHARCLASS_ALNUM();                                                                \
1372 	REXEC_FBC_UTF8_SCAN(                                                   \
1373 	    if (tmp == ! (TeSt2_UtF8)) { \
1374 		tmp = !tmp;                                                    \
1375 		IF_SUCCESS;                                                    \
1376 	    }                                                                  \
1377 	    else {                                                             \
1378 		IF_FAIL;                                                       \
1379 	    }                                                                  \
1380 	);                                                                     \
1381 
1382 /* The only difference between the BOUND and NBOUND cases is that
1383  * REXEC_FBC_TRYIT is called when matched in BOUND, and when non-matched in
1384  * NBOUND.  This is accomplished by passing it in either the if or else clause,
1385  * with the other one being empty */
1386 #define FBC_BOUND(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
1387     FBC_BOUND_COMMON(UTF8_LOAD(TEST1_UTF8, TEST2_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER), TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
1388 
1389 #define FBC_BOUND_NOLOAD(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
1390     FBC_BOUND_COMMON(UTF8_NOLOAD(TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER), TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
1391 
1392 #define FBC_NBOUND(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
1393     FBC_BOUND_COMMON(UTF8_LOAD(TEST1_UTF8, TEST2_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT), TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
1394 
1395 #define FBC_NBOUND_NOLOAD(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
1396     FBC_BOUND_COMMON(UTF8_NOLOAD(TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT), TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
1397 
1398 
1399 /* Common to the BOUND and NBOUND cases.  Unfortunately the UTF8 tests need to
1400  * be passed in completely with the variable name being tested, which isn't
1401  * such a clean interface, but this is easier to read than it was before.  We
1402  * are looking for the boundary (or non-boundary between a word and non-word
1403  * character.  The utf8 and non-utf8 cases have the same logic, but the details
1404  * must be different.  Find the "wordness" of the character just prior to this
1405  * one, and compare it with the wordness of this one.  If they differ, we have
1406  * a boundary.  At the beginning of the string, pretend that the previous
1407  * character was a new-line */
1408 #define FBC_BOUND_COMMON(UTF8_CODE, TEST_NON_UTF8, IF_SUCCESS, IF_FAIL) \
1409     if (utf8_target) {                                                         \
1410 		UTF8_CODE \
1411     }                                                                          \
1412     else {  /* Not utf8 */                                                     \
1413 	tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';                         \
1414 	tmp = TEST_NON_UTF8(tmp);                                              \
1415 	REXEC_FBC_SCAN(                                                        \
1416 	    if (tmp == ! TEST_NON_UTF8((U8) *s)) {                             \
1417 		tmp = !tmp;                                                    \
1418 		IF_SUCCESS;                                                    \
1419 	    }                                                                  \
1420 	    else {                                                             \
1421 		IF_FAIL;                                                       \
1422 	    }                                                                  \
1423 	);                                                                     \
1424     }                                                                          \
1425     if ((!prog->minlen && tmp) && (!reginfo || regtry(reginfo, &s)))           \
1426 	goto got_it;
1427 
1428 /* We know what class REx starts with.  Try to find this position... */
1429 /* if reginfo is NULL, its a dryrun */
1430 /* annoyingly all the vars in this routine have different names from their counterparts
1431    in regmatch. /grrr */
1432 
1433 STATIC char *
1434 S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
1435     const char *strend, regmatch_info *reginfo, bool is_utf8_pat)
1436 {
1437     dVAR;
1438     const I32 doevery = (prog->intflags & PREGf_SKIP) == 0;
1439     char *pat_string;   /* The pattern's exactish string */
1440     char *pat_end;	    /* ptr to end char of pat_string */
1441     re_fold_t folder;	/* Function for computing non-utf8 folds */
1442     const U8 *fold_array;   /* array for folding ords < 256 */
1443     STRLEN ln;
1444     STRLEN lnc;
1445     U8 c1;
1446     U8 c2;
1447     char *e;
1448     I32 tmp = 1;	/* Scratch variable? */
1449     const bool utf8_target = PL_reg_match_utf8;
1450     UV utf8_fold_flags = 0;
1451     bool to_complement = FALSE; /* Invert the result?  Taking the xor of this
1452                                    with a result inverts that result, as 0^1 =
1453                                    1 and 1^1 = 0 */
1454     _char_class_number classnum;
1455 
1456     RXi_GET_DECL(prog,progi);
1457 
1458     PERL_ARGS_ASSERT_FIND_BYCLASS;
1459 
1460     /* We know what class it must start with. */
1461     switch (OP(c)) {
1462     case ANYOF:
1463     case ANYOF_SYNTHETIC:
1464     case ANYOF_WARN_SUPER:
1465         if (utf8_target) {
1466             REXEC_FBC_UTF8_CLASS_SCAN(
1467                       reginclass(prog, c, (U8*)s, utf8_target));
1468         }
1469         else {
1470             REXEC_FBC_CLASS_SCAN(REGINCLASS(prog, c, (U8*)s));
1471         }
1472         break;
1473     case CANY:
1474         REXEC_FBC_SCAN(
1475             if (tmp && (!reginfo || regtry(reginfo, &s)))
1476                 goto got_it;
1477             else
1478                 tmp = doevery;
1479         );
1480         break;
1481 
1482     case EXACTFA:
1483         if (is_utf8_pat || utf8_target) {
1484             utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
1485             goto do_exactf_utf8;
1486         }
1487         fold_array = PL_fold_latin1;    /* Latin1 folds are not affected by */
1488         folder = foldEQ_latin1;	        /* /a, except the sharp s one which */
1489         goto do_exactf_non_utf8;	/* isn't dealt with by these */
1490 
1491     case EXACTF:
1492         if (utf8_target) {
1493 
1494             /* regcomp.c already folded this if pattern is in UTF-8 */
1495             utf8_fold_flags = 0;
1496             goto do_exactf_utf8;
1497         }
1498         fold_array = PL_fold;
1499         folder = foldEQ;
1500         goto do_exactf_non_utf8;
1501 
1502     case EXACTFL:
1503         if (is_utf8_pat || utf8_target) {
1504             utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
1505             goto do_exactf_utf8;
1506         }
1507         fold_array = PL_fold_locale;
1508         folder = foldEQ_locale;
1509         goto do_exactf_non_utf8;
1510 
1511     case EXACTFU_SS:
1512         if (is_utf8_pat) {
1513             utf8_fold_flags = FOLDEQ_S2_ALREADY_FOLDED;
1514         }
1515         goto do_exactf_utf8;
1516 
1517     case EXACTFU_TRICKYFOLD:
1518     case EXACTFU:
1519         if (is_utf8_pat || utf8_target) {
1520             utf8_fold_flags = is_utf8_pat ? FOLDEQ_S2_ALREADY_FOLDED : 0;
1521             goto do_exactf_utf8;
1522         }
1523 
1524         /* Any 'ss' in the pattern should have been replaced by regcomp,
1525          * so we don't have to worry here about this single special case
1526          * in the Latin1 range */
1527         fold_array = PL_fold_latin1;
1528         folder = foldEQ_latin1;
1529 
1530         /* FALL THROUGH */
1531 
1532     do_exactf_non_utf8: /* Neither pattern nor string are UTF8, and there
1533                            are no glitches with fold-length differences
1534                            between the target string and pattern */
1535 
1536         /* The idea in the non-utf8 EXACTF* cases is to first find the
1537          * first character of the EXACTF* node and then, if necessary,
1538          * case-insensitively compare the full text of the node.  c1 is the
1539          * first character.  c2 is its fold.  This logic will not work for
1540          * Unicode semantics and the german sharp ss, which hence should
1541          * not be compiled into a node that gets here. */
1542         pat_string = STRING(c);
1543         ln  = STR_LEN(c);	/* length to match in octets/bytes */
1544 
1545         /* We know that we have to match at least 'ln' bytes (which is the
1546          * same as characters, since not utf8).  If we have to match 3
1547          * characters, and there are only 2 availabe, we know without
1548          * trying that it will fail; so don't start a match past the
1549          * required minimum number from the far end */
1550         e = HOP3c(strend, -((I32)ln), s);
1551 
1552         if (!reginfo && e < s) {
1553             e = s;			/* Due to minlen logic of intuit() */
1554         }
1555 
1556         c1 = *pat_string;
1557         c2 = fold_array[c1];
1558         if (c1 == c2) { /* If char and fold are the same */
1559             REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1);
1560         }
1561         else {
1562             REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1 || *(U8*)s == c2);
1563         }
1564         break;
1565 
1566     do_exactf_utf8:
1567     {
1568         unsigned expansion;
1569 
1570         /* If one of the operands is in utf8, we can't use the simpler folding
1571          * above, due to the fact that many different characters can have the
1572          * same fold, or portion of a fold, or different- length fold */
1573         pat_string = STRING(c);
1574         ln  = STR_LEN(c);	/* length to match in octets/bytes */
1575         pat_end = pat_string + ln;
1576         lnc = is_utf8_pat       /* length to match in characters */
1577                 ? utf8_length((U8 *) pat_string, (U8 *) pat_end)
1578                 : ln;
1579 
1580         /* We have 'lnc' characters to match in the pattern, but because of
1581          * multi-character folding, each character in the target can match
1582          * up to 3 characters (Unicode guarantees it will never exceed
1583          * this) if it is utf8-encoded; and up to 2 if not (based on the
1584          * fact that the Latin 1 folds are already determined, and the
1585          * only multi-char fold in that range is the sharp-s folding to
1586          * 'ss'.  Thus, a pattern character can match as little as 1/3 of a
1587          * string character.  Adjust lnc accordingly, rounding up, so that
1588          * if we need to match at least 4+1/3 chars, that really is 5. */
1589         expansion = (utf8_target) ? UTF8_MAX_FOLD_CHAR_EXPAND : 2;
1590         lnc = (lnc + expansion - 1) / expansion;
1591 
1592         /* As in the non-UTF8 case, if we have to match 3 characters, and
1593          * only 2 are left, it's guaranteed to fail, so don't start a
1594          * match that would require us to go beyond the end of the string
1595          */
1596         e = HOP3c(strend, -((I32)lnc), s);
1597 
1598         if (!reginfo && e < s) {
1599             e = s;			/* Due to minlen logic of intuit() */
1600         }
1601 
1602         /* XXX Note that we could recalculate e to stop the loop earlier,
1603          * as the worst case expansion above will rarely be met, and as we
1604          * go along we would usually find that e moves further to the left.
1605          * This would happen only after we reached the point in the loop
1606          * where if there were no expansion we should fail.  Unclear if
1607          * worth the expense */
1608 
1609         while (s <= e) {
1610             char *my_strend= (char *)strend;
1611             if (foldEQ_utf8_flags(s, &my_strend, 0,  utf8_target,
1612                   pat_string, NULL, ln, is_utf8_pat, utf8_fold_flags)
1613                 && (!reginfo || regtry(reginfo, &s)) )
1614             {
1615                 goto got_it;
1616             }
1617             s += (utf8_target) ? UTF8SKIP(s) : 1;
1618         }
1619         break;
1620     }
1621     case BOUNDL:
1622         RXp_MATCH_TAINTED_on(prog);
1623         FBC_BOUND(isWORDCHAR_LC,
1624                   isWORDCHAR_LC_uvchr(UNI_TO_NATIVE(tmp)),
1625                   isWORDCHAR_LC_utf8((U8*)s));
1626         break;
1627     case NBOUNDL:
1628         RXp_MATCH_TAINTED_on(prog);
1629         FBC_NBOUND(isWORDCHAR_LC,
1630                    isWORDCHAR_LC_uvchr(UNI_TO_NATIVE(tmp)),
1631                    isWORDCHAR_LC_utf8((U8*)s));
1632         break;
1633     case BOUND:
1634         FBC_BOUND(isWORDCHAR,
1635                   isWORDCHAR_uni(tmp),
1636                   cBOOL(swash_fetch(PL_utf8_swash_ptrs[_CC_WORDCHAR], (U8*)s, utf8_target)));
1637         break;
1638     case BOUNDA:
1639         FBC_BOUND_NOLOAD(isWORDCHAR_A,
1640                          isWORDCHAR_A(tmp),
1641                          isWORDCHAR_A((U8*)s));
1642         break;
1643     case NBOUND:
1644         FBC_NBOUND(isWORDCHAR,
1645                    isWORDCHAR_uni(tmp),
1646                    cBOOL(swash_fetch(PL_utf8_swash_ptrs[_CC_WORDCHAR], (U8*)s, utf8_target)));
1647         break;
1648     case NBOUNDA:
1649         FBC_NBOUND_NOLOAD(isWORDCHAR_A,
1650                           isWORDCHAR_A(tmp),
1651                           isWORDCHAR_A((U8*)s));
1652         break;
1653     case BOUNDU:
1654         FBC_BOUND(isWORDCHAR_L1,
1655                   isWORDCHAR_uni(tmp),
1656                   cBOOL(swash_fetch(PL_utf8_swash_ptrs[_CC_WORDCHAR], (U8*)s, utf8_target)));
1657         break;
1658     case NBOUNDU:
1659         FBC_NBOUND(isWORDCHAR_L1,
1660                    isWORDCHAR_uni(tmp),
1661                    cBOOL(swash_fetch(PL_utf8_swash_ptrs[_CC_WORDCHAR], (U8*)s, utf8_target)));
1662         break;
1663     case LNBREAK:
1664         REXEC_FBC_CSCAN(is_LNBREAK_utf8_safe(s, strend),
1665                         is_LNBREAK_latin1_safe(s, strend)
1666         );
1667         break;
1668 
1669     /* The argument to all the POSIX node types is the class number to pass to
1670      * _generic_isCC() to build a mask for searching in PL_charclass[] */
1671 
1672     case NPOSIXL:
1673         to_complement = 1;
1674         /* FALLTHROUGH */
1675 
1676     case POSIXL:
1677         RXp_MATCH_TAINTED_on(prog);
1678         REXEC_FBC_CSCAN(to_complement ^ cBOOL(isFOO_utf8_lc(FLAGS(c), (U8 *) s)),
1679                         to_complement ^ cBOOL(isFOO_lc(FLAGS(c), *s)));
1680         break;
1681 
1682     case NPOSIXD:
1683         to_complement = 1;
1684         /* FALLTHROUGH */
1685 
1686     case POSIXD:
1687         if (utf8_target) {
1688             goto posix_utf8;
1689         }
1690         goto posixa;
1691 
1692     case NPOSIXA:
1693         if (utf8_target) {
1694             /* The complement of something that matches only ASCII matches all
1695              * UTF-8 variant code points, plus everything in ASCII that isn't
1696              * in the class */
1697             REXEC_FBC_UTF8_CLASS_SCAN(! UTF8_IS_INVARIANT(*s)
1698                                       || ! _generic_isCC_A(*s, FLAGS(c)));
1699             break;
1700         }
1701 
1702         to_complement = 1;
1703         /* FALLTHROUGH */
1704 
1705     case POSIXA:
1706       posixa:
1707         /* Don't need to worry about utf8, as it can match only a single
1708          * byte invariant character. */
1709         REXEC_FBC_CLASS_SCAN(
1710                         to_complement ^ cBOOL(_generic_isCC_A(*s, FLAGS(c))));
1711         break;
1712 
1713     case NPOSIXU:
1714         to_complement = 1;
1715         /* FALLTHROUGH */
1716 
1717     case POSIXU:
1718         if (! utf8_target) {
1719             REXEC_FBC_CLASS_SCAN(to_complement ^ cBOOL(_generic_isCC(*s,
1720                                                                     FLAGS(c))));
1721         }
1722         else {
1723 
1724       posix_utf8:
1725             classnum = (_char_class_number) FLAGS(c);
1726             if (classnum < _FIRST_NON_SWASH_CC) {
1727                 while (s < strend) {
1728 
1729                     /* We avoid loading in the swash as long as possible, but
1730                      * should we have to, we jump to a separate loop.  This
1731                      * extra 'if' statement is what keeps this code from being
1732                      * just a call to REXEC_FBC_UTF8_CLASS_SCAN() */
1733                     if (UTF8_IS_ABOVE_LATIN1(*s)) {
1734                         goto found_above_latin1;
1735                     }
1736                     if ((UTF8_IS_INVARIANT(*s)
1737                          && to_complement ^ cBOOL(_generic_isCC((U8) *s,
1738                                                                 classnum)))
1739                         || (UTF8_IS_DOWNGRADEABLE_START(*s)
1740                             && to_complement ^ cBOOL(
1741                                 _generic_isCC(TWO_BYTE_UTF8_TO_UNI(*s, *(s + 1)),
1742                                               classnum))))
1743                     {
1744                         if (tmp && (!reginfo || regtry(reginfo, &s)))
1745                             goto got_it;
1746                         else {
1747                             tmp = doevery;
1748                         }
1749                     }
1750                     else {
1751                         tmp = 1;
1752                     }
1753                     s += UTF8SKIP(s);
1754                 }
1755             }
1756             else switch (classnum) {    /* These classes are implemented as
1757                                            macros */
1758                 case _CC_ENUM_SPACE: /* XXX would require separate code if we
1759                                         revert the change of \v matching this */
1760                     /* FALL THROUGH */
1761 
1762                 case _CC_ENUM_PSXSPC:
1763                     REXEC_FBC_UTF8_CLASS_SCAN(
1764                                         to_complement ^ cBOOL(isSPACE_utf8(s)));
1765                     break;
1766 
1767                 case _CC_ENUM_BLANK:
1768                     REXEC_FBC_UTF8_CLASS_SCAN(
1769                                         to_complement ^ cBOOL(isBLANK_utf8(s)));
1770                     break;
1771 
1772                 case _CC_ENUM_XDIGIT:
1773                     REXEC_FBC_UTF8_CLASS_SCAN(
1774                                        to_complement ^ cBOOL(isXDIGIT_utf8(s)));
1775                     break;
1776 
1777                 case _CC_ENUM_VERTSPACE:
1778                     REXEC_FBC_UTF8_CLASS_SCAN(
1779                                        to_complement ^ cBOOL(isVERTWS_utf8(s)));
1780                     break;
1781 
1782                 case _CC_ENUM_CNTRL:
1783                     REXEC_FBC_UTF8_CLASS_SCAN(
1784                                         to_complement ^ cBOOL(isCNTRL_utf8(s)));
1785                     break;
1786 
1787                 default:
1788                     Perl_croak(aTHX_ "panic: find_byclass() node %d='%s' has an unexpected character class '%d'", OP(c), PL_reg_name[OP(c)], classnum);
1789                     assert(0); /* NOTREACHED */
1790             }
1791         }
1792         break;
1793 
1794       found_above_latin1:   /* Here we have to load a swash to get the result
1795                                for the current code point */
1796         if (! PL_utf8_swash_ptrs[classnum]) {
1797             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
1798             PL_utf8_swash_ptrs[classnum] =
1799                     _core_swash_init("utf8", swash_property_names[classnum],
1800                                      &PL_sv_undef, 1, 0, NULL, &flags);
1801         }
1802 
1803         /* This is a copy of the loop above for swash classes, though using the
1804          * FBC macro instead of being expanded out.  Since we've loaded the
1805          * swash, we don't have to check for that each time through the loop */
1806         REXEC_FBC_UTF8_CLASS_SCAN(
1807                 to_complement ^ cBOOL(_generic_utf8(
1808                                       classnum,
1809                                       s,
1810                                       swash_fetch(PL_utf8_swash_ptrs[classnum],
1811                                                   (U8 *) s, TRUE))));
1812         break;
1813 
1814     case AHOCORASICKC:
1815     case AHOCORASICK:
1816         {
1817             DECL_TRIE_TYPE(c);
1818             /* what trie are we using right now */
1819             reg_ac_data *aho = (reg_ac_data*)progi->data->data[ ARG( c ) ];
1820             reg_trie_data *trie = (reg_trie_data*)progi->data->data[ aho->trie ];
1821             HV *widecharmap = MUTABLE_HV(progi->data->data[ aho->trie + 1 ]);
1822 
1823             const char *last_start = strend - trie->minlen;
1824 #ifdef DEBUGGING
1825             const char *real_start = s;
1826 #endif
1827             STRLEN maxlen = trie->maxlen;
1828             SV *sv_points;
1829             U8 **points; /* map of where we were in the input string
1830                             when reading a given char. For ASCII this
1831                             is unnecessary overhead as the relationship
1832                             is always 1:1, but for Unicode, especially
1833                             case folded Unicode this is not true. */
1834             U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
1835             U8 *bitmap=NULL;
1836 
1837 
1838             GET_RE_DEBUG_FLAGS_DECL;
1839 
1840             /* We can't just allocate points here. We need to wrap it in
1841              * an SV so it gets freed properly if there is a croak while
1842              * running the match */
1843             ENTER;
1844             SAVETMPS;
1845             sv_points=newSV(maxlen * sizeof(U8 *));
1846             SvCUR_set(sv_points,
1847                 maxlen * sizeof(U8 *));
1848             SvPOK_on(sv_points);
1849             sv_2mortal(sv_points);
1850             points=(U8**)SvPV_nolen(sv_points );
1851             if ( trie_type != trie_utf8_fold
1852                  && (trie->bitmap || OP(c)==AHOCORASICKC) )
1853             {
1854                 if (trie->bitmap)
1855                     bitmap=(U8*)trie->bitmap;
1856                 else
1857                     bitmap=(U8*)ANYOF_BITMAP(c);
1858             }
1859             /* this is the Aho-Corasick algorithm modified a touch
1860                to include special handling for long "unknown char" sequences.
1861                The basic idea being that we use AC as long as we are dealing
1862                with a possible matching char, when we encounter an unknown char
1863                (and we have not encountered an accepting state) we scan forward
1864                until we find a legal starting char.
1865                AC matching is basically that of trie matching, except that when
1866                we encounter a failing transition, we fall back to the current
1867                states "fail state", and try the current char again, a process
1868                we repeat until we reach the root state, state 1, or a legal
1869                transition. If we fail on the root state then we can either
1870                terminate if we have reached an accepting state previously, or
1871                restart the entire process from the beginning if we have not.
1872 
1873              */
1874             while (s <= last_start) {
1875                 const U32 uniflags = UTF8_ALLOW_DEFAULT;
1876                 U8 *uc = (U8*)s;
1877                 U16 charid = 0;
1878                 U32 base = 1;
1879                 U32 state = 1;
1880                 UV uvc = 0;
1881                 STRLEN len = 0;
1882                 STRLEN foldlen = 0;
1883                 U8 *uscan = (U8*)NULL;
1884                 U8 *leftmost = NULL;
1885 #ifdef DEBUGGING
1886                 U32 accepted_word= 0;
1887 #endif
1888                 U32 pointpos = 0;
1889 
1890                 while ( state && uc <= (U8*)strend ) {
1891                     int failed=0;
1892                     U32 word = aho->states[ state ].wordnum;
1893 
1894                     if( state==1 ) {
1895                         if ( bitmap ) {
1896                             DEBUG_TRIE_EXECUTE_r(
1897                                 if ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
1898                                     dump_exec_pos( (char *)uc, c, strend, real_start,
1899                                         (char *)uc, utf8_target );
1900                                     PerlIO_printf( Perl_debug_log,
1901                                         " Scanning for legal start char...\n");
1902                                 }
1903                             );
1904                             if (utf8_target) {
1905                                 while ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
1906                                     uc += UTF8SKIP(uc);
1907                                 }
1908                             } else {
1909                                 while ( uc <= (U8*)last_start  && !BITMAP_TEST(bitmap,*uc) ) {
1910                                     uc++;
1911                                 }
1912                             }
1913                             s= (char *)uc;
1914                         }
1915                         if (uc >(U8*)last_start) break;
1916                     }
1917 
1918                     if ( word ) {
1919                         U8 *lpos= points[ (pointpos - trie->wordinfo[word].len) % maxlen ];
1920                         if (!leftmost || lpos < leftmost) {
1921                             DEBUG_r(accepted_word=word);
1922                             leftmost= lpos;
1923                         }
1924                         if (base==0) break;
1925 
1926                     }
1927                     points[pointpos++ % maxlen]= uc;
1928                     if (foldlen || uc < (U8*)strend) {
1929                         REXEC_TRIE_READ_CHAR(trie_type, trie,
1930                                          widecharmap, uc,
1931                                          uscan, len, uvc, charid, foldlen,
1932                                          foldbuf, uniflags);
1933                         DEBUG_TRIE_EXECUTE_r({
1934                             dump_exec_pos( (char *)uc, c, strend,
1935                                         real_start, s, utf8_target);
1936                             PerlIO_printf(Perl_debug_log,
1937                                 " Charid:%3u CP:%4"UVxf" ",
1938                                  charid, uvc);
1939                         });
1940                     }
1941                     else {
1942                         len = 0;
1943                         charid = 0;
1944                     }
1945 
1946 
1947                     do {
1948 #ifdef DEBUGGING
1949                         word = aho->states[ state ].wordnum;
1950 #endif
1951                         base = aho->states[ state ].trans.base;
1952 
1953                         DEBUG_TRIE_EXECUTE_r({
1954                             if (failed)
1955                                 dump_exec_pos( (char *)uc, c, strend, real_start,
1956                                     s,   utf8_target );
1957                             PerlIO_printf( Perl_debug_log,
1958                                 "%sState: %4"UVxf", word=%"UVxf,
1959                                 failed ? " Fail transition to " : "",
1960                                 (UV)state, (UV)word);
1961                         });
1962                         if ( base ) {
1963                             U32 tmp;
1964                             I32 offset;
1965                             if (charid &&
1966                                  ( ((offset = base + charid
1967                                     - 1 - trie->uniquecharcount)) >= 0)
1968                                  && ((U32)offset < trie->lasttrans)
1969                                  && trie->trans[offset].check == state
1970                                  && (tmp=trie->trans[offset].next))
1971                             {
1972                                 DEBUG_TRIE_EXECUTE_r(
1973                                     PerlIO_printf( Perl_debug_log," - legal\n"));
1974                                 state = tmp;
1975                                 break;
1976                             }
1977                             else {
1978                                 DEBUG_TRIE_EXECUTE_r(
1979                                     PerlIO_printf( Perl_debug_log," - fail\n"));
1980                                 failed = 1;
1981                                 state = aho->fail[state];
1982                             }
1983                         }
1984                         else {
1985                             /* we must be accepting here */
1986                             DEBUG_TRIE_EXECUTE_r(
1987                                     PerlIO_printf( Perl_debug_log," - accepting\n"));
1988                             failed = 1;
1989                             break;
1990                         }
1991                     } while(state);
1992                     uc += len;
1993                     if (failed) {
1994                         if (leftmost)
1995                             break;
1996                         if (!state) state = 1;
1997                     }
1998                 }
1999                 if ( aho->states[ state ].wordnum ) {
2000                     U8 *lpos = points[ (pointpos - trie->wordinfo[aho->states[ state ].wordnum].len) % maxlen ];
2001                     if (!leftmost || lpos < leftmost) {
2002                         DEBUG_r(accepted_word=aho->states[ state ].wordnum);
2003                         leftmost = lpos;
2004                     }
2005                 }
2006                 if (leftmost) {
2007                     s = (char*)leftmost;
2008                     DEBUG_TRIE_EXECUTE_r({
2009                         PerlIO_printf(
2010                             Perl_debug_log,"Matches word #%"UVxf" at position %"IVdf". Trying full pattern...\n",
2011                             (UV)accepted_word, (IV)(s - real_start)
2012                         );
2013                     });
2014                     if (!reginfo || regtry(reginfo, &s)) {
2015                         FREETMPS;
2016                         LEAVE;
2017                         goto got_it;
2018                     }
2019                     s = HOPc(s,1);
2020                     DEBUG_TRIE_EXECUTE_r({
2021                         PerlIO_printf( Perl_debug_log,"Pattern failed. Looking for new start point...\n");
2022                     });
2023                 } else {
2024                     DEBUG_TRIE_EXECUTE_r(
2025                         PerlIO_printf( Perl_debug_log,"No match.\n"));
2026                     break;
2027                 }
2028             }
2029             FREETMPS;
2030             LEAVE;
2031         }
2032         break;
2033     default:
2034         Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
2035         break;
2036     }
2037     return 0;
2038   got_it:
2039     return s;
2040 }
2041 
2042 
2043 /*
2044  - regexec_flags - match a regexp against a string
2045  */
2046 I32
2047 Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
2048 	      char *strbeg, I32 minend, SV *sv, void *data, U32 flags)
2049 /* stringarg: the point in the string at which to begin matching */
2050 /* strend:    pointer to null at end of string */
2051 /* strbeg:    real beginning of string */
2052 /* minend:    end of match must be >= minend bytes after stringarg. */
2053 /* sv:        SV being matched: only used for utf8 flag, pos() etc; string
2054  *            itself is accessed via the pointers above */
2055 /* data:      May be used for some additional optimizations.
2056               Currently its only used, with a U32 cast, for transmitting
2057               the ganch offset when doing a /g match. This will change */
2058 /* nosave:    For optimizations. */
2059 
2060 {
2061     dVAR;
2062     struct regexp *const prog = ReANY(rx);
2063     char *s;
2064     regnode *c;
2065     char *startpos = stringarg;
2066     I32 minlen;		/* must match at least this many chars */
2067     I32 dontbother = 0;	/* how many characters not to try at end */
2068     I32 end_shift = 0;			/* Same for the end. */		/* CC */
2069     I32 scream_pos = -1;		/* Internal iterator of scream. */
2070     char *scream_olds = NULL;
2071     const bool utf8_target = cBOOL(DO_UTF8(sv));
2072     I32 multiline;
2073     RXi_GET_DECL(prog,progi);
2074     regmatch_info reginfo;  /* create some info to pass to regtry etc */
2075     regexp_paren_pair *swap = NULL;
2076     GET_RE_DEBUG_FLAGS_DECL;
2077 
2078     PERL_ARGS_ASSERT_REGEXEC_FLAGS;
2079     PERL_UNUSED_ARG(data);
2080 
2081     /* Be paranoid... */
2082     if (prog == NULL || startpos == NULL) {
2083 	Perl_croak(aTHX_ "NULL regexp parameter");
2084 	return 0;
2085     }
2086 
2087     multiline = prog->extflags & RXf_PMf_MULTILINE;
2088     reginfo.prog = rx;	 /* Yes, sorry that this is confusing.  */
2089 
2090     RX_MATCH_UTF8_set(rx, utf8_target);
2091     DEBUG_EXECUTE_r(
2092         debug_start_match(rx, utf8_target, startpos, strend,
2093         "Matching");
2094     );
2095 
2096     minlen = prog->minlen;
2097 
2098     if (strend - startpos < (minlen+(prog->check_offset_min<0?prog->check_offset_min:0))) {
2099         DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
2100 			      "String too short [regexec_flags]...\n"));
2101 	goto phooey;
2102     }
2103 
2104 
2105     /* Check validity of program. */
2106     if (UCHARAT(progi->program) != REG_MAGIC) {
2107 	Perl_croak(aTHX_ "corrupted regexp program");
2108     }
2109 
2110     RX_MATCH_TAINTED_off(rx);
2111     PL_reg_state.re_state_eval_setup_done = FALSE;
2112     PL_reg_maxiter = 0;
2113 
2114     reginfo.is_utf8_pat = cBOOL(RX_UTF8(rx));
2115     reginfo.warned = FALSE;
2116     /* Mark beginning of line for ^ and lookbehind. */
2117     reginfo.bol = startpos; /* XXX not used ??? */
2118     PL_bostr  = strbeg;
2119     reginfo.sv = sv;
2120 
2121     /* Mark end of line for $ (and such) */
2122     PL_regeol = strend;
2123 
2124     /* see how far we have to get to not match where we matched before */
2125     reginfo.till = startpos+minend;
2126 
2127     /* If there is a "must appear" string, look for it. */
2128     s = startpos;
2129 
2130     if (prog->extflags & RXf_GPOS_SEEN) { /* Need to set reginfo->ganch */
2131 	MAGIC *mg;
2132 	if (flags & REXEC_IGNOREPOS){	/* Means: check only at start */
2133 	    reginfo.ganch = startpos + prog->gofs;
2134 	    DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
2135 	      "GPOS IGNOREPOS: reginfo.ganch = startpos + %"UVxf"\n",(UV)prog->gofs));
2136 	} else if (sv && SvTYPE(sv) >= SVt_PVMG
2137 		  && SvMAGIC(sv)
2138 		  && (mg = mg_find(sv, PERL_MAGIC_regex_global))
2139 		  && mg->mg_len >= 0) {
2140 	    reginfo.ganch = strbeg + mg->mg_len;	/* Defined pos() */
2141 	    DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
2142 		"GPOS MAGIC: reginfo.ganch = strbeg + %"IVdf"\n",(IV)mg->mg_len));
2143 
2144 	    if (prog->extflags & RXf_ANCH_GPOS) {
2145 	        if (s > reginfo.ganch)
2146 		    goto phooey;
2147 		s = reginfo.ganch - prog->gofs;
2148 	        DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
2149 		     "GPOS ANCH_GPOS: s = ganch - %"UVxf"\n",(UV)prog->gofs));
2150 		if (s < strbeg)
2151 		    goto phooey;
2152 	    }
2153 	}
2154 	else if (data) {
2155 	    reginfo.ganch = strbeg + PTR2UV(data);
2156             DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
2157 		 "GPOS DATA: reginfo.ganch= strbeg + %"UVxf"\n",PTR2UV(data)));
2158 
2159 	} else {				/* pos() not defined */
2160 	    reginfo.ganch = strbeg;
2161             DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
2162 		 "GPOS: reginfo.ganch = strbeg\n"));
2163 	}
2164     }
2165     if (PL_curpm && (PM_GETRE(PL_curpm) == rx)) {
2166         /* We have to be careful. If the previous successful match
2167            was from this regex we don't want a subsequent partially
2168            successful match to clobber the old results.
2169            So when we detect this possibility we add a swap buffer
2170            to the re, and switch the buffer each match. If we fail,
2171            we switch it back; otherwise we leave it swapped.
2172         */
2173         swap = prog->offs;
2174         /* do we need a save destructor here for eval dies? */
2175         Newxz(prog->offs, (prog->nparens + 1), regexp_paren_pair);
2176 	DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
2177 	    "rex=0x%"UVxf" saving  offs: orig=0x%"UVxf" new=0x%"UVxf"\n",
2178 	    PTR2UV(prog),
2179 	    PTR2UV(swap),
2180 	    PTR2UV(prog->offs)
2181 	));
2182     }
2183     if (!(flags & REXEC_CHECKED) && (prog->check_substr != NULL || prog->check_utf8 != NULL)) {
2184 	re_scream_pos_data d;
2185 
2186 	d.scream_olds = &scream_olds;
2187 	d.scream_pos = &scream_pos;
2188 	s = re_intuit_start(rx, sv, s, strend, flags, &d);
2189 	if (!s) {
2190 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Not present...\n"));
2191 	    goto phooey;	/* not present */
2192 	}
2193     }
2194 
2195 
2196 
2197     /* Simplest case:  anchored match need be tried only once. */
2198     /*  [unless only anchor is BOL and multiline is set] */
2199     if (prog->extflags & (RXf_ANCH & ~RXf_ANCH_GPOS)) {
2200 	if (s == startpos && regtry(&reginfo, &startpos))
2201 	    goto got_it;
2202 	else if (multiline || (prog->intflags & PREGf_IMPLICIT)
2203 		 || (prog->extflags & RXf_ANCH_MBOL)) /* XXXX SBOL? */
2204 	{
2205 	    char *end;
2206 
2207 	    if (minlen)
2208 		dontbother = minlen - 1;
2209 	    end = HOP3c(strend, -dontbother, strbeg) - 1;
2210 	    /* for multiline we only have to try after newlines */
2211 	    if (prog->check_substr || prog->check_utf8) {
2212                 /* because of the goto we can not easily reuse the macros for bifurcating the
2213                    unicode/non-unicode match modes here like we do elsewhere - demerphq */
2214                 if (utf8_target) {
2215                     if (s == startpos)
2216                         goto after_try_utf8;
2217                     while (1) {
2218                         if (regtry(&reginfo, &s)) {
2219                             goto got_it;
2220                         }
2221                       after_try_utf8:
2222                         if (s > end) {
2223                             goto phooey;
2224                         }
2225                         if (prog->extflags & RXf_USE_INTUIT) {
2226                             s = re_intuit_start(rx, sv, s + UTF8SKIP(s), strend, flags, NULL);
2227                             if (!s) {
2228                                 goto phooey;
2229                             }
2230                         }
2231                         else {
2232                             s += UTF8SKIP(s);
2233                         }
2234                     }
2235                 } /* end search for check string in unicode */
2236                 else {
2237                     if (s == startpos) {
2238                         goto after_try_latin;
2239                     }
2240                     while (1) {
2241                         if (regtry(&reginfo, &s)) {
2242                             goto got_it;
2243                         }
2244                       after_try_latin:
2245                         if (s > end) {
2246                             goto phooey;
2247                         }
2248                         if (prog->extflags & RXf_USE_INTUIT) {
2249                             s = re_intuit_start(rx, sv, s + 1, strend, flags, NULL);
2250                             if (!s) {
2251                                 goto phooey;
2252                             }
2253                         }
2254                         else {
2255                             s++;
2256                         }
2257                     }
2258                 } /* end search for check string in latin*/
2259 	    } /* end search for check string */
2260 	    else { /* search for newline */
2261 		if (s > startpos) {
2262                     /*XXX: The s-- is almost definitely wrong here under unicode - demeprhq*/
2263 		    s--;
2264 		}
2265 		/* We can use a more efficient search as newlines are the same in unicode as they are in latin */
2266 		while (s <= end) { /* note it could be possible to match at the end of the string */
2267 		    if (*s++ == '\n') {	/* don't need PL_utf8skip here */
2268 			if (regtry(&reginfo, &s))
2269 			    goto got_it;
2270 		    }
2271 		}
2272 	    } /* end search for newline */
2273 	} /* end anchored/multiline check string search */
2274 	goto phooey;
2275     } else if (RXf_GPOS_CHECK == (prog->extflags & RXf_GPOS_CHECK))
2276     {
2277         /* the warning about reginfo.ganch being used without initialization
2278            is bogus -- we set it above, when prog->extflags & RXf_GPOS_SEEN
2279            and we only enter this block when the same bit is set. */
2280         char *tmp_s = reginfo.ganch - prog->gofs;
2281 
2282 	if (tmp_s >= strbeg && regtry(&reginfo, &tmp_s))
2283 	    goto got_it;
2284 	goto phooey;
2285     }
2286 
2287     /* Messy cases:  unanchored match. */
2288     if ((prog->anchored_substr || prog->anchored_utf8) && prog->intflags & PREGf_SKIP) {
2289 	/* we have /x+whatever/ */
2290 	/* it must be a one character string (XXXX Except is_utf8_pat?) */
2291 	char ch;
2292 #ifdef DEBUGGING
2293 	int did_match = 0;
2294 #endif
2295 	if (utf8_target) {
2296             if (! prog->anchored_utf8) {
2297                 to_utf8_substr(prog);
2298             }
2299             ch = SvPVX_const(prog->anchored_utf8)[0];
2300 	    REXEC_FBC_SCAN(
2301 		if (*s == ch) {
2302 		    DEBUG_EXECUTE_r( did_match = 1 );
2303 		    if (regtry(&reginfo, &s)) goto got_it;
2304 		    s += UTF8SKIP(s);
2305 		    while (s < strend && *s == ch)
2306 			s += UTF8SKIP(s);
2307 		}
2308 	    );
2309 
2310 	}
2311 	else {
2312             if (! prog->anchored_substr) {
2313                 if (! to_byte_substr(prog)) {
2314                     NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
2315                 }
2316             }
2317             ch = SvPVX_const(prog->anchored_substr)[0];
2318 	    REXEC_FBC_SCAN(
2319 		if (*s == ch) {
2320 		    DEBUG_EXECUTE_r( did_match = 1 );
2321 		    if (regtry(&reginfo, &s)) goto got_it;
2322 		    s++;
2323 		    while (s < strend && *s == ch)
2324 			s++;
2325 		}
2326 	    );
2327 	}
2328 	DEBUG_EXECUTE_r(if (!did_match)
2329 		PerlIO_printf(Perl_debug_log,
2330                                   "Did not find anchored character...\n")
2331                );
2332     }
2333     else if (prog->anchored_substr != NULL
2334 	      || prog->anchored_utf8 != NULL
2335 	      || ((prog->float_substr != NULL || prog->float_utf8 != NULL)
2336 		  && prog->float_max_offset < strend - s)) {
2337 	SV *must;
2338 	I32 back_max;
2339 	I32 back_min;
2340 	char *last;
2341 	char *last1;		/* Last position checked before */
2342 #ifdef DEBUGGING
2343 	int did_match = 0;
2344 #endif
2345 	if (prog->anchored_substr || prog->anchored_utf8) {
2346 	    if (utf8_target) {
2347                 if (! prog->anchored_utf8) {
2348                     to_utf8_substr(prog);
2349                 }
2350                 must = prog->anchored_utf8;
2351             }
2352             else {
2353                 if (! prog->anchored_substr) {
2354                     if (! to_byte_substr(prog)) {
2355                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
2356                     }
2357                 }
2358                 must = prog->anchored_substr;
2359             }
2360 	    back_max = back_min = prog->anchored_offset;
2361 	} else {
2362 	    if (utf8_target) {
2363                 if (! prog->float_utf8) {
2364                     to_utf8_substr(prog);
2365                 }
2366                 must = prog->float_utf8;
2367             }
2368             else {
2369                 if (! prog->float_substr) {
2370                     if (! to_byte_substr(prog)) {
2371                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
2372                     }
2373                 }
2374                 must = prog->float_substr;
2375             }
2376 	    back_max = prog->float_max_offset;
2377 	    back_min = prog->float_min_offset;
2378 	}
2379 
2380         if (back_min<0) {
2381 	    last = strend;
2382 	} else {
2383             last = HOP3c(strend,	/* Cannot start after this */
2384         	  -(I32)(CHR_SVLEN(must)
2385         		 - (SvTAIL(must) != 0) + back_min), strbeg);
2386         }
2387 	if (s > PL_bostr)
2388 	    last1 = HOPc(s, -1);
2389 	else
2390 	    last1 = s - 1;	/* bogus */
2391 
2392 	/* XXXX check_substr already used to find "s", can optimize if
2393 	   check_substr==must. */
2394 	scream_pos = -1;
2395 	dontbother = end_shift;
2396 	strend = HOPc(strend, -dontbother);
2397 	while ( (s <= last) &&
2398 		(s = fbm_instr((unsigned char*)HOP3(s, back_min, (back_min<0 ? strbeg : strend)),
2399 				  (unsigned char*)strend, must,
2400 				  multiline ? FBMrf_MULTILINE : 0)) ) {
2401 	    DEBUG_EXECUTE_r( did_match = 1 );
2402 	    if (HOPc(s, -back_max) > last1) {
2403 		last1 = HOPc(s, -back_min);
2404 		s = HOPc(s, -back_max);
2405 	    }
2406 	    else {
2407 		char * const t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
2408 
2409 		last1 = HOPc(s, -back_min);
2410 		s = t;
2411 	    }
2412 	    if (utf8_target) {
2413 		while (s <= last1) {
2414 		    if (regtry(&reginfo, &s))
2415 			goto got_it;
2416                     if (s >= last1) {
2417                         s++; /* to break out of outer loop */
2418                         break;
2419                     }
2420                     s += UTF8SKIP(s);
2421 		}
2422 	    }
2423 	    else {
2424 		while (s <= last1) {
2425 		    if (regtry(&reginfo, &s))
2426 			goto got_it;
2427 		    s++;
2428 		}
2429 	    }
2430 	}
2431 	DEBUG_EXECUTE_r(if (!did_match) {
2432             RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
2433                 SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
2434             PerlIO_printf(Perl_debug_log, "Did not find %s substr %s%s...\n",
2435 			      ((must == prog->anchored_substr || must == prog->anchored_utf8)
2436 			       ? "anchored" : "floating"),
2437                 quoted, RE_SV_TAIL(must));
2438         });
2439 	goto phooey;
2440     }
2441     else if ( (c = progi->regstclass) ) {
2442 	if (minlen) {
2443 	    const OPCODE op = OP(progi->regstclass);
2444 	    /* don't bother with what can't match */
2445 	    if (PL_regkind[op] != EXACT && op != CANY && PL_regkind[op] != TRIE)
2446 	        strend = HOPc(strend, -(minlen - 1));
2447 	}
2448 	DEBUG_EXECUTE_r({
2449 	    SV * const prop = sv_newmortal();
2450 	    regprop(prog, prop, c);
2451 	    {
2452 		RE_PV_QUOTED_DECL(quoted,utf8_target,PERL_DEBUG_PAD_ZERO(1),
2453 		    s,strend-s,60);
2454 		PerlIO_printf(Perl_debug_log,
2455 		    "Matching stclass %.*s against %s (%d bytes)\n",
2456 		    (int)SvCUR(prop), SvPVX_const(prop),
2457 		     quoted, (int)(strend - s));
2458 	    }
2459 	});
2460         if (find_byclass(prog, c, s, strend, &reginfo, reginfo.is_utf8_pat))
2461 	    goto got_it;
2462 	DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass... [regexec_flags]\n"));
2463     }
2464     else {
2465 	dontbother = 0;
2466 	if (prog->float_substr != NULL || prog->float_utf8 != NULL) {
2467 	    /* Trim the end. */
2468 	    char *last= NULL;
2469 	    SV* float_real;
2470 	    STRLEN len;
2471 	    const char *little;
2472 
2473 	    if (utf8_target) {
2474                 if (! prog->float_utf8) {
2475                     to_utf8_substr(prog);
2476                 }
2477                 float_real = prog->float_utf8;
2478             }
2479             else {
2480                 if (! prog->float_substr) {
2481                     if (! to_byte_substr(prog)) {
2482                         NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
2483                     }
2484                 }
2485                 float_real = prog->float_substr;
2486             }
2487 
2488             little = SvPV_const(float_real, len);
2489 	    if (SvTAIL(float_real)) {
2490                     /* This means that float_real contains an artificial \n on
2491                      * the end due to the presence of something like this:
2492                      * /foo$/ where we can match both "foo" and "foo\n" at the
2493                      * end of the string.  So we have to compare the end of the
2494                      * string first against the float_real without the \n and
2495                      * then against the full float_real with the string.  We
2496                      * have to watch out for cases where the string might be
2497                      * smaller than the float_real or the float_real without
2498                      * the \n. */
2499 		    char *checkpos= strend - len;
2500 		    DEBUG_OPTIMISE_r(
2501 			PerlIO_printf(Perl_debug_log,
2502 			    "%sChecking for float_real.%s\n",
2503 			    PL_colors[4], PL_colors[5]));
2504 		    if (checkpos + 1 < strbeg) {
2505                         /* can't match, even if we remove the trailing \n
2506                          * string is too short to match */
2507 			DEBUG_EXECUTE_r(
2508 			    PerlIO_printf(Perl_debug_log,
2509 				"%sString shorter than required trailing substring, cannot match.%s\n",
2510 				PL_colors[4], PL_colors[5]));
2511 			goto phooey;
2512 		    } else if (memEQ(checkpos + 1, little, len - 1)) {
2513                         /* can match, the end of the string matches without the
2514                          * "\n" */
2515 			last = checkpos + 1;
2516 		    } else if (checkpos < strbeg) {
2517                         /* cant match, string is too short when the "\n" is
2518                          * included */
2519 			DEBUG_EXECUTE_r(
2520 			    PerlIO_printf(Perl_debug_log,
2521 				"%sString does not contain required trailing substring, cannot match.%s\n",
2522 				PL_colors[4], PL_colors[5]));
2523 			goto phooey;
2524 		    } else if (!multiline) {
2525                         /* non multiline match, so compare with the "\n" at the
2526                          * end of the string */
2527 			if (memEQ(checkpos, little, len)) {
2528 			    last= checkpos;
2529 			} else {
2530 			    DEBUG_EXECUTE_r(
2531 				PerlIO_printf(Perl_debug_log,
2532 				    "%sString does not contain required trailing substring, cannot match.%s\n",
2533 				    PL_colors[4], PL_colors[5]));
2534 			    goto phooey;
2535 			}
2536 		    } else {
2537                         /* multiline match, so we have to search for a place
2538                          * where the full string is located */
2539 			goto find_last;
2540 		    }
2541 	    } else {
2542 		  find_last:
2543 		    if (len)
2544 			last = rninstr(s, strend, little, little + len);
2545 		    else
2546 			last = strend;	/* matching "$" */
2547 	    }
2548 	    if (!last) {
2549                 /* at one point this block contained a comment which was
2550                  * probably incorrect, which said that this was a "should not
2551                  * happen" case.  Even if it was true when it was written I am
2552                  * pretty sure it is not anymore, so I have removed the comment
2553                  * and replaced it with this one. Yves */
2554 		DEBUG_EXECUTE_r(
2555 		    PerlIO_printf(Perl_debug_log,
2556 			"String does not contain required substring, cannot match.\n"
2557 	            ));
2558 		goto phooey;
2559 	    }
2560 	    dontbother = strend - last + prog->float_min_offset;
2561 	}
2562 	if (minlen && (dontbother < minlen))
2563 	    dontbother = minlen - 1;
2564 	strend -= dontbother; 		   /* this one's always in bytes! */
2565 	/* We don't know much -- general case. */
2566 	if (utf8_target) {
2567 	    for (;;) {
2568 		if (regtry(&reginfo, &s))
2569 		    goto got_it;
2570 		if (s >= strend)
2571 		    break;
2572 		s += UTF8SKIP(s);
2573 	    };
2574 	}
2575 	else {
2576 	    do {
2577 		if (regtry(&reginfo, &s))
2578 		    goto got_it;
2579 	    } while (s++ < strend);
2580 	}
2581     }
2582 
2583     /* Failure. */
2584     goto phooey;
2585 
2586 got_it:
2587     DEBUG_BUFFERS_r(
2588 	if (swap)
2589 	    PerlIO_printf(Perl_debug_log,
2590 		"rex=0x%"UVxf" freeing offs: 0x%"UVxf"\n",
2591 		PTR2UV(prog),
2592 		PTR2UV(swap)
2593 	    );
2594     );
2595     Safefree(swap);
2596 
2597     if (PL_reg_state.re_state_eval_setup_done)
2598 	restore_pos(aTHX_ prog);
2599     if (RXp_PAREN_NAMES(prog))
2600         (void)hv_iterinit(RXp_PAREN_NAMES(prog));
2601 
2602     /* make sure $`, $&, $', and $digit will work later */
2603     if ( !(flags & REXEC_NOT_FIRST) ) {
2604 	if (flags & REXEC_COPY_STR) {
2605 #ifdef PERL_ANY_COW
2606 	    if (SvCANCOW(sv)) {
2607 		if (DEBUG_C_TEST) {
2608 		    PerlIO_printf(Perl_debug_log,
2609 				  "Copy on write: regexp capture, type %d\n",
2610 				  (int) SvTYPE(sv));
2611 		}
2612                 RX_MATCH_COPY_FREE(rx);
2613 		prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
2614 		prog->subbeg = (char *)SvPVX_const(prog->saved_copy);
2615 		assert (SvPOKp(prog->saved_copy));
2616                 prog->sublen  = PL_regeol - strbeg;
2617                 prog->suboffset = 0;
2618                 prog->subcoffset = 0;
2619 	    } else
2620 #endif
2621 	    {
2622                 I32 min = 0;
2623                 I32 max = PL_regeol - strbeg;
2624                 I32 sublen;
2625 
2626                 if (    (flags & REXEC_COPY_SKIP_POST)
2627                     && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
2628                     && !(PL_sawampersand & SAWAMPERSAND_RIGHT)
2629                 ) { /* don't copy $' part of string */
2630                     U32 n = 0;
2631                     max = -1;
2632                     /* calculate the right-most part of the string covered
2633                      * by a capture. Due to look-ahead, this may be to
2634                      * the right of $&, so we have to scan all captures */
2635                     while (n <= prog->lastparen) {
2636                         if (prog->offs[n].end > max)
2637                             max = prog->offs[n].end;
2638                         n++;
2639                     }
2640                     if (max == -1)
2641                         max = (PL_sawampersand & SAWAMPERSAND_LEFT)
2642                                 ? prog->offs[0].start
2643                                 : 0;
2644                     assert(max >= 0 && max <= PL_regeol - strbeg);
2645                 }
2646 
2647                 if (    (flags & REXEC_COPY_SKIP_PRE)
2648                     && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
2649                     && !(PL_sawampersand & SAWAMPERSAND_LEFT)
2650                 ) { /* don't copy $` part of string */
2651                     U32 n = 0;
2652                     min = max;
2653                     /* calculate the left-most part of the string covered
2654                      * by a capture. Due to look-behind, this may be to
2655                      * the left of $&, so we have to scan all captures */
2656                     while (min && n <= prog->lastparen) {
2657                         if (   prog->offs[n].start != -1
2658                             && prog->offs[n].start < min)
2659                         {
2660                             min = prog->offs[n].start;
2661                         }
2662                         n++;
2663                     }
2664                     if ((PL_sawampersand & SAWAMPERSAND_RIGHT)
2665                         && min >  prog->offs[0].end
2666                     )
2667                         min = prog->offs[0].end;
2668 
2669                 }
2670 
2671                 assert(min >= 0 && min <= max && min <= PL_regeol - strbeg);
2672                 sublen = max - min;
2673 
2674                 if (RX_MATCH_COPIED(rx)) {
2675                     if (sublen > prog->sublen)
2676                         prog->subbeg =
2677                                 (char*)saferealloc(prog->subbeg, sublen+1);
2678                 }
2679                 else
2680                     prog->subbeg = (char*)safemalloc(sublen+1);
2681                 Copy(strbeg + min, prog->subbeg, sublen, char);
2682                 prog->subbeg[sublen] = '\0';
2683                 prog->suboffset = min;
2684                 prog->sublen = sublen;
2685                 RX_MATCH_COPIED_on(rx);
2686 	    }
2687             prog->subcoffset = prog->suboffset;
2688             if (prog->suboffset && utf8_target) {
2689                 /* Convert byte offset to chars.
2690                  * XXX ideally should only compute this if @-/@+
2691                  * has been seen, a la PL_sawampersand ??? */
2692 
2693                 /* If there's a direct correspondence between the
2694                  * string which we're matching and the original SV,
2695                  * then we can use the utf8 len cache associated with
2696                  * the SV. In particular, it means that under //g,
2697                  * sv_pos_b2u() will use the previously cached
2698                  * position to speed up working out the new length of
2699                  * subcoffset, rather than counting from the start of
2700                  * the string each time. This stops
2701                  *   $x = "\x{100}" x 1E6; 1 while $x =~ /(.)/g;
2702                  * from going quadratic */
2703                 if (SvPOKp(sv) && SvPVX(sv) == strbeg)
2704                     sv_pos_b2u(sv, &(prog->subcoffset));
2705                 else
2706                     prog->subcoffset = utf8_length((U8*)strbeg,
2707                                         (U8*)(strbeg+prog->suboffset));
2708             }
2709 	}
2710 	else {
2711             RX_MATCH_COPY_FREE(rx);
2712 	    prog->subbeg = strbeg;
2713 	    prog->suboffset = 0;
2714 	    prog->subcoffset = 0;
2715 	    prog->sublen = PL_regeol - strbeg;	/* strend may have been modified */
2716 	}
2717     }
2718 
2719     return 1;
2720 
2721 phooey:
2722     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch failed%s\n",
2723 			  PL_colors[4], PL_colors[5]));
2724     if (PL_reg_state.re_state_eval_setup_done)
2725 	restore_pos(aTHX_ prog);
2726     if (swap) {
2727         /* we failed :-( roll it back */
2728 	DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
2729 	    "rex=0x%"UVxf" rolling back offs: freeing=0x%"UVxf" restoring=0x%"UVxf"\n",
2730 	    PTR2UV(prog),
2731 	    PTR2UV(prog->offs),
2732 	    PTR2UV(swap)
2733 	));
2734         Safefree(prog->offs);
2735         prog->offs = swap;
2736     }
2737     return 0;
2738 }
2739 
2740 
2741 /* Set which rex is pointed to by PL_reg_state, handling ref counting.
2742  * Do inc before dec, in case old and new rex are the same */
2743 #define SET_reg_curpm(Re2) \
2744     if (PL_reg_state.re_state_eval_setup_done) {    \
2745 	(void)ReREFCNT_inc(Re2);		    \
2746 	ReREFCNT_dec(PM_GETRE(PL_reg_curpm));	    \
2747 	PM_SETRE((PL_reg_curpm), (Re2));	    \
2748     }
2749 
2750 
2751 /*
2752  - regtry - try match at specific point
2753  */
2754 STATIC I32			/* 0 failure, 1 success */
2755 S_regtry(pTHX_ regmatch_info *reginfo, char **startposp)
2756 {
2757     dVAR;
2758     CHECKPOINT lastcp;
2759     REGEXP *const rx = reginfo->prog;
2760     regexp *const prog = ReANY(rx);
2761     I32 result;
2762     RXi_GET_DECL(prog,progi);
2763     GET_RE_DEBUG_FLAGS_DECL;
2764 
2765     PERL_ARGS_ASSERT_REGTRY;
2766 
2767     reginfo->cutpoint=NULL;
2768 
2769     if ((prog->extflags & RXf_EVAL_SEEN)
2770 	&& !PL_reg_state.re_state_eval_setup_done)
2771     {
2772 	MAGIC *mg;
2773 
2774 	PL_reg_state.re_state_eval_setup_done = TRUE;
2775 	if (reginfo->sv) {
2776 	    /* Make $_ available to executed code. */
2777 	    if (reginfo->sv != DEFSV) {
2778 		SAVE_DEFSV;
2779 		DEFSV_set(reginfo->sv);
2780 	    }
2781 
2782 	    if (!(SvTYPE(reginfo->sv) >= SVt_PVMG && SvMAGIC(reginfo->sv)
2783 		  && (mg = mg_find(reginfo->sv, PERL_MAGIC_regex_global)))) {
2784 		/* prepare for quick setting of pos */
2785 #ifdef PERL_OLD_COPY_ON_WRITE
2786 		if (SvIsCOW(reginfo->sv))
2787 		    sv_force_normal_flags(reginfo->sv, 0);
2788 #endif
2789 		mg = sv_magicext(reginfo->sv, NULL, PERL_MAGIC_regex_global,
2790 				 &PL_vtbl_mglob, NULL, 0);
2791 		mg->mg_len = -1;
2792 	    }
2793 	    PL_reg_magic    = mg;
2794 	    PL_reg_oldpos   = mg->mg_len;
2795 	    SAVEDESTRUCTOR_X(restore_pos, prog);
2796         }
2797         if (!PL_reg_curpm) {
2798 	    Newxz(PL_reg_curpm, 1, PMOP);
2799 #ifdef USE_ITHREADS
2800             {
2801 		SV* const repointer = &PL_sv_undef;
2802                 /* this regexp is also owned by the new PL_reg_curpm, which
2803 		   will try to free it.  */
2804                 av_push(PL_regex_padav, repointer);
2805                 PL_reg_curpm->op_pmoffset = av_len(PL_regex_padav);
2806                 PL_regex_pad = AvARRAY(PL_regex_padav);
2807             }
2808 #endif
2809         }
2810 	SET_reg_curpm(rx);
2811 	PL_reg_oldcurpm = PL_curpm;
2812 	PL_curpm = PL_reg_curpm;
2813 	if (RXp_MATCH_COPIED(prog)) {
2814 	    /*  Here is a serious problem: we cannot rewrite subbeg,
2815 		since it may be needed if this match fails.  Thus
2816 		$` inside (?{}) could fail... */
2817 	    PL_reg_oldsaved = prog->subbeg;
2818 	    PL_reg_oldsavedlen = prog->sublen;
2819 	    PL_reg_oldsavedoffset = prog->suboffset;
2820 	    PL_reg_oldsavedcoffset = prog->suboffset;
2821 #ifdef PERL_ANY_COW
2822 	    PL_nrs = prog->saved_copy;
2823 #endif
2824 	    RXp_MATCH_COPIED_off(prog);
2825 	}
2826 	else
2827 	    PL_reg_oldsaved = NULL;
2828 	prog->subbeg = PL_bostr;
2829 	prog->suboffset = 0;
2830 	prog->subcoffset = 0;
2831 	prog->sublen = PL_regeol - PL_bostr; /* strend may have been modified */
2832     }
2833 #ifdef DEBUGGING
2834     PL_reg_starttry = *startposp;
2835 #endif
2836     prog->offs[0].start = *startposp - PL_bostr;
2837     prog->lastparen = 0;
2838     prog->lastcloseparen = 0;
2839 
2840     /* XXXX What this code is doing here?!!!  There should be no need
2841        to do this again and again, prog->lastparen should take care of
2842        this!  --ilya*/
2843 
2844     /* Tests pat.t#187 and split.t#{13,14} seem to depend on this code.
2845      * Actually, the code in regcppop() (which Ilya may be meaning by
2846      * prog->lastparen), is not needed at all by the test suite
2847      * (op/regexp, op/pat, op/split), but that code is needed otherwise
2848      * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
2849      * Meanwhile, this code *is* needed for the
2850      * above-mentioned test suite tests to succeed.  The common theme
2851      * on those tests seems to be returning null fields from matches.
2852      * --jhi updated by dapm */
2853 #if 1
2854     if (prog->nparens) {
2855 	regexp_paren_pair *pp = prog->offs;
2856 	I32 i;
2857 	for (i = prog->nparens; i > (I32)prog->lastparen; i--) {
2858 	    ++pp;
2859 	    pp->start = -1;
2860 	    pp->end = -1;
2861 	}
2862     }
2863 #endif
2864     REGCP_SET(lastcp);
2865     result = regmatch(reginfo, *startposp, progi->program + 1);
2866     if (result != -1) {
2867 	prog->offs[0].end = result;
2868 	return 1;
2869     }
2870     if (reginfo->cutpoint)
2871         *startposp= reginfo->cutpoint;
2872     REGCP_UNWIND(lastcp);
2873     return 0;
2874 }
2875 
2876 
2877 #define sayYES goto yes
2878 #define sayNO goto no
2879 #define sayNO_SILENT goto no_silent
2880 
2881 /* we dont use STMT_START/END here because it leads to
2882    "unreachable code" warnings, which are bogus, but distracting. */
2883 #define CACHEsayNO \
2884     if (ST.cache_mask) \
2885        PL_reg_poscache[ST.cache_offset] |= ST.cache_mask; \
2886     sayNO
2887 
2888 /* this is used to determine how far from the left messages like
2889    'failed...' are printed. It should be set such that messages
2890    are inline with the regop output that created them.
2891 */
2892 #define REPORT_CODE_OFF 32
2893 
2894 
2895 #define CHRTEST_UNINIT -1001 /* c1/c2 haven't been calculated yet */
2896 #define CHRTEST_VOID   -1000 /* the c1/c2 "next char" test should be skipped */
2897 #define CHRTEST_NOT_A_CP_1 -999
2898 #define CHRTEST_NOT_A_CP_2 -998
2899 
2900 #define SLAB_FIRST(s) (&(s)->states[0])
2901 #define SLAB_LAST(s)  (&(s)->states[PERL_REGMATCH_SLAB_SLOTS-1])
2902 
2903 /* grab a new slab and return the first slot in it */
2904 
2905 STATIC regmatch_state *
2906 S_push_slab(pTHX)
2907 {
2908 #if PERL_VERSION < 9 && !defined(PERL_CORE)
2909     dMY_CXT;
2910 #endif
2911     regmatch_slab *s = PL_regmatch_slab->next;
2912     if (!s) {
2913 	Newx(s, 1, regmatch_slab);
2914 	s->prev = PL_regmatch_slab;
2915 	s->next = NULL;
2916 	PL_regmatch_slab->next = s;
2917     }
2918     PL_regmatch_slab = s;
2919     return SLAB_FIRST(s);
2920 }
2921 
2922 
2923 /* push a new state then goto it */
2924 
2925 #define PUSH_STATE_GOTO(state, node, input) \
2926     pushinput = input; \
2927     scan = node; \
2928     st->resume_state = state; \
2929     goto push_state;
2930 
2931 /* push a new state with success backtracking, then goto it */
2932 
2933 #define PUSH_YES_STATE_GOTO(state, node, input) \
2934     pushinput = input; \
2935     scan = node; \
2936     st->resume_state = state; \
2937     goto push_yes_state;
2938 
2939 
2940 
2941 
2942 /*
2943 
2944 regmatch() - main matching routine
2945 
2946 This is basically one big switch statement in a loop. We execute an op,
2947 set 'next' to point the next op, and continue. If we come to a point which
2948 we may need to backtrack to on failure such as (A|B|C), we push a
2949 backtrack state onto the backtrack stack. On failure, we pop the top
2950 state, and re-enter the loop at the state indicated. If there are no more
2951 states to pop, we return failure.
2952 
2953 Sometimes we also need to backtrack on success; for example /A+/, where
2954 after successfully matching one A, we need to go back and try to
2955 match another one; similarly for lookahead assertions: if the assertion
2956 completes successfully, we backtrack to the state just before the assertion
2957 and then carry on.  In these cases, the pushed state is marked as
2958 'backtrack on success too'. This marking is in fact done by a chain of
2959 pointers, each pointing to the previous 'yes' state. On success, we pop to
2960 the nearest yes state, discarding any intermediate failure-only states.
2961 Sometimes a yes state is pushed just to force some cleanup code to be
2962 called at the end of a successful match or submatch; e.g. (??{$re}) uses
2963 it to free the inner regex.
2964 
2965 Note that failure backtracking rewinds the cursor position, while
2966 success backtracking leaves it alone.
2967 
2968 A pattern is complete when the END op is executed, while a subpattern
2969 such as (?=foo) is complete when the SUCCESS op is executed. Both of these
2970 ops trigger the "pop to last yes state if any, otherwise return true"
2971 behaviour.
2972 
2973 A common convention in this function is to use A and B to refer to the two
2974 subpatterns (or to the first nodes thereof) in patterns like /A*B/: so A is
2975 the subpattern to be matched possibly multiple times, while B is the entire
2976 rest of the pattern. Variable and state names reflect this convention.
2977 
2978 The states in the main switch are the union of ops and failure/success of
2979 substates associated with with that op.  For example, IFMATCH is the op
2980 that does lookahead assertions /(?=A)B/ and so the IFMATCH state means
2981 'execute IFMATCH'; while IFMATCH_A is a state saying that we have just
2982 successfully matched A and IFMATCH_A_fail is a state saying that we have
2983 just failed to match A. Resume states always come in pairs. The backtrack
2984 state we push is marked as 'IFMATCH_A', but when that is popped, we resume
2985 at IFMATCH_A or IFMATCH_A_fail, depending on whether we are backtracking
2986 on success or failure.
2987 
2988 The struct that holds a backtracking state is actually a big union, with
2989 one variant for each major type of op. The variable st points to the
2990 top-most backtrack struct. To make the code clearer, within each
2991 block of code we #define ST to alias the relevant union.
2992 
2993 Here's a concrete example of a (vastly oversimplified) IFMATCH
2994 implementation:
2995 
2996     switch (state) {
2997     ....
2998 
2999 #define ST st->u.ifmatch
3000 
3001     case IFMATCH: // we are executing the IFMATCH op, (?=A)B
3002 	ST.foo = ...; // some state we wish to save
3003 	...
3004 	// push a yes backtrack state with a resume value of
3005 	// IFMATCH_A/IFMATCH_A_fail, then continue execution at the
3006 	// first node of A:
3007 	PUSH_YES_STATE_GOTO(IFMATCH_A, A, newinput);
3008 	// NOTREACHED
3009 
3010     case IFMATCH_A: // we have successfully executed A; now continue with B
3011 	next = B;
3012 	bar = ST.foo; // do something with the preserved value
3013 	break;
3014 
3015     case IFMATCH_A_fail: // A failed, so the assertion failed
3016 	...;   // do some housekeeping, then ...
3017 	sayNO; // propagate the failure
3018 
3019 #undef ST
3020 
3021     ...
3022     }
3023 
3024 For any old-timers reading this who are familiar with the old recursive
3025 approach, the code above is equivalent to:
3026 
3027     case IFMATCH: // we are executing the IFMATCH op, (?=A)B
3028     {
3029 	int foo = ...
3030 	...
3031 	if (regmatch(A)) {
3032 	    next = B;
3033 	    bar = foo;
3034 	    break;
3035 	}
3036 	...;   // do some housekeeping, then ...
3037 	sayNO; // propagate the failure
3038     }
3039 
3040 The topmost backtrack state, pointed to by st, is usually free. If you
3041 want to claim it, populate any ST.foo fields in it with values you wish to
3042 save, then do one of
3043 
3044 	PUSH_STATE_GOTO(resume_state, node, newinput);
3045 	PUSH_YES_STATE_GOTO(resume_state, node, newinput);
3046 
3047 which sets that backtrack state's resume value to 'resume_state', pushes a
3048 new free entry to the top of the backtrack stack, then goes to 'node'.
3049 On backtracking, the free slot is popped, and the saved state becomes the
3050 new free state. An ST.foo field in this new top state can be temporarily
3051 accessed to retrieve values, but once the main loop is re-entered, it
3052 becomes available for reuse.
3053 
3054 Note that the depth of the backtrack stack constantly increases during the
3055 left-to-right execution of the pattern, rather than going up and down with
3056 the pattern nesting. For example the stack is at its maximum at Z at the
3057 end of the pattern, rather than at X in the following:
3058 
3059     /(((X)+)+)+....(Y)+....Z/
3060 
3061 The only exceptions to this are lookahead/behind assertions and the cut,
3062 (?>A), which pop all the backtrack states associated with A before
3063 continuing.
3064 
3065 Backtrack state structs are allocated in slabs of about 4K in size.
3066 PL_regmatch_state and st always point to the currently active state,
3067 and PL_regmatch_slab points to the slab currently containing
3068 PL_regmatch_state.  The first time regmatch() is called, the first slab is
3069 allocated, and is never freed until interpreter destruction. When the slab
3070 is full, a new one is allocated and chained to the end. At exit from
3071 regmatch(), slabs allocated since entry are freed.
3072 
3073 */
3074 
3075 
3076 #define DEBUG_STATE_pp(pp)				    \
3077     DEBUG_STATE_r({					    \
3078 	DUMP_EXEC_POS(locinput, scan, utf8_target);		    \
3079 	PerlIO_printf(Perl_debug_log,			    \
3080 	    "    %*s"pp" %s%s%s%s%s\n",			    \
3081 	    depth*2, "",				    \
3082 	    PL_reg_name[st->resume_state],                     \
3083 	    ((st==yes_state||st==mark_state) ? "[" : ""),   \
3084 	    ((st==yes_state) ? "Y" : ""),                   \
3085 	    ((st==mark_state) ? "M" : ""),                  \
3086 	    ((st==yes_state||st==mark_state) ? "]" : "")    \
3087 	);                                                  \
3088     });
3089 
3090 
3091 #define REG_NODE_NUM(x) ((x) ? (int)((x)-prog) : -1)
3092 
3093 #ifdef DEBUGGING
3094 
3095 STATIC void
3096 S_debug_start_match(pTHX_ const REGEXP *prog, const bool utf8_target,
3097     const char *start, const char *end, const char *blurb)
3098 {
3099     const bool utf8_pat = RX_UTF8(prog) ? 1 : 0;
3100 
3101     PERL_ARGS_ASSERT_DEBUG_START_MATCH;
3102 
3103     if (!PL_colorset)
3104             reginitcolors();
3105     {
3106         RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0),
3107             RX_PRECOMP_const(prog), RX_PRELEN(prog), 60);
3108 
3109         RE_PV_QUOTED_DECL(s1, utf8_target, PERL_DEBUG_PAD_ZERO(1),
3110             start, end - start, 60);
3111 
3112         PerlIO_printf(Perl_debug_log,
3113             "%s%s REx%s %s against %s\n",
3114 		       PL_colors[4], blurb, PL_colors[5], s0, s1);
3115 
3116         if (utf8_target||utf8_pat)
3117             PerlIO_printf(Perl_debug_log, "UTF-8 %s%s%s...\n",
3118                 utf8_pat ? "pattern" : "",
3119                 utf8_pat && utf8_target ? " and " : "",
3120                 utf8_target ? "string" : ""
3121             );
3122     }
3123 }
3124 
3125 STATIC void
3126 S_dump_exec_pos(pTHX_ const char *locinput,
3127                       const regnode *scan,
3128                       const char *loc_regeol,
3129                       const char *loc_bostr,
3130                       const char *loc_reg_starttry,
3131                       const bool utf8_target)
3132 {
3133     const int docolor = *PL_colors[0] || *PL_colors[2] || *PL_colors[4];
3134     const int taill = (docolor ? 10 : 7); /* 3 chars for "> <" */
3135     int l = (loc_regeol - locinput) > taill ? taill : (loc_regeol - locinput);
3136     /* The part of the string before starttry has one color
3137        (pref0_len chars), between starttry and current
3138        position another one (pref_len - pref0_len chars),
3139        after the current position the third one.
3140        We assume that pref0_len <= pref_len, otherwise we
3141        decrease pref0_len.  */
3142     int pref_len = (locinput - loc_bostr) > (5 + taill) - l
3143 	? (5 + taill) - l : locinput - loc_bostr;
3144     int pref0_len;
3145 
3146     PERL_ARGS_ASSERT_DUMP_EXEC_POS;
3147 
3148     while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput - pref_len)))
3149 	pref_len++;
3150     pref0_len = pref_len  - (locinput - loc_reg_starttry);
3151     if (l + pref_len < (5 + taill) && l < loc_regeol - locinput)
3152 	l = ( loc_regeol - locinput > (5 + taill) - pref_len
3153 	      ? (5 + taill) - pref_len : loc_regeol - locinput);
3154     while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput + l)))
3155 	l--;
3156     if (pref0_len < 0)
3157 	pref0_len = 0;
3158     if (pref0_len > pref_len)
3159 	pref0_len = pref_len;
3160     {
3161 	const int is_uni = (utf8_target && OP(scan) != CANY) ? 1 : 0;
3162 
3163 	RE_PV_COLOR_DECL(s0,len0,is_uni,PERL_DEBUG_PAD(0),
3164 	    (locinput - pref_len),pref0_len, 60, 4, 5);
3165 
3166 	RE_PV_COLOR_DECL(s1,len1,is_uni,PERL_DEBUG_PAD(1),
3167 		    (locinput - pref_len + pref0_len),
3168 		    pref_len - pref0_len, 60, 2, 3);
3169 
3170 	RE_PV_COLOR_DECL(s2,len2,is_uni,PERL_DEBUG_PAD(2),
3171 		    locinput, loc_regeol - locinput, 10, 0, 1);
3172 
3173 	const STRLEN tlen=len0+len1+len2;
3174 	PerlIO_printf(Perl_debug_log,
3175 		    "%4"IVdf" <%.*s%.*s%s%.*s>%*s|",
3176 		    (IV)(locinput - loc_bostr),
3177 		    len0, s0,
3178 		    len1, s1,
3179 		    (docolor ? "" : "> <"),
3180 		    len2, s2,
3181 		    (int)(tlen > 19 ? 0 :  19 - tlen),
3182 		    "");
3183     }
3184 }
3185 
3186 #endif
3187 
3188 /* reg_check_named_buff_matched()
3189  * Checks to see if a named buffer has matched. The data array of
3190  * buffer numbers corresponding to the buffer is expected to reside
3191  * in the regexp->data->data array in the slot stored in the ARG() of
3192  * node involved. Note that this routine doesn't actually care about the
3193  * name, that information is not preserved from compilation to execution.
3194  * Returns the index of the leftmost defined buffer with the given name
3195  * or 0 if non of the buffers matched.
3196  */
3197 STATIC I32
3198 S_reg_check_named_buff_matched(pTHX_ const regexp *rex, const regnode *scan)
3199 {
3200     I32 n;
3201     RXi_GET_DECL(rex,rexi);
3202     SV *sv_dat= MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
3203     I32 *nums=(I32*)SvPVX(sv_dat);
3204 
3205     PERL_ARGS_ASSERT_REG_CHECK_NAMED_BUFF_MATCHED;
3206 
3207     for ( n=0; n<SvIVX(sv_dat); n++ ) {
3208         if ((I32)rex->lastparen >= nums[n] &&
3209             rex->offs[nums[n]].end != -1)
3210         {
3211             return nums[n];
3212         }
3213     }
3214     return 0;
3215 }
3216 
3217 
3218 /* free all slabs above current one  - called during LEAVE_SCOPE */
3219 
3220 STATIC void
3221 S_clear_backtrack_stack(pTHX_ void *p)
3222 {
3223     regmatch_slab *s = PL_regmatch_slab->next;
3224     PERL_UNUSED_ARG(p);
3225 
3226     if (!s)
3227 	return;
3228     PL_regmatch_slab->next = NULL;
3229     while (s) {
3230 	regmatch_slab * const osl = s;
3231 	s = s->next;
3232 	Safefree(osl);
3233     }
3234 }
3235 static bool
3236 S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p,
3237         U8* c1_utf8, int *c2p, U8* c2_utf8, bool is_utf8_pat)
3238 {
3239     /* This function determines if there are one or two characters that match
3240      * the first character of the passed-in EXACTish node <text_node>, and if
3241      * so, returns them in the passed-in pointers.
3242      *
3243      * If it determines that no possible character in the target string can
3244      * match, it returns FALSE; otherwise TRUE.  (The FALSE situation occurs if
3245      * the first character in <text_node> requires UTF-8 to represent, and the
3246      * target string isn't in UTF-8.)
3247      *
3248      * If there are more than two characters that could match the beginning of
3249      * <text_node>, or if more context is required to determine a match or not,
3250      * it sets both *<c1p> and *<c2p> to CHRTEST_VOID.
3251      *
3252      * The motiviation behind this function is to allow the caller to set up
3253      * tight loops for matching.  If <text_node> is of type EXACT, there is
3254      * only one possible character that can match its first character, and so
3255      * the situation is quite simple.  But things get much more complicated if
3256      * folding is involved.  It may be that the first character of an EXACTFish
3257      * node doesn't participate in any possible fold, e.g., punctuation, so it
3258      * can be matched only by itself.  The vast majority of characters that are
3259      * in folds match just two things, their lower and upper-case equivalents.
3260      * But not all are like that; some have multiple possible matches, or match
3261      * sequences of more than one character.  This function sorts all that out.
3262      *
3263      * Consider the patterns A*B or A*?B where A and B are arbitrary.  In a
3264      * loop of trying to match A*, we know we can't exit where the thing
3265      * following it isn't a B.  And something can't be a B unless it is the
3266      * beginning of B.  By putting a quick test for that beginning in a tight
3267      * loop, we can rule out things that can't possibly be B without having to
3268      * break out of the loop, thus avoiding work.  Similarly, if A is a single
3269      * character, we can make a tight loop matching A*, using the outputs of
3270      * this function.
3271      *
3272      * If the target string to match isn't in UTF-8, and there aren't
3273      * complications which require CHRTEST_VOID, *<c1p> and *<c2p> are set to
3274      * the one or two possible octets (which are characters in this situation)
3275      * that can match.  In all cases, if there is only one character that can
3276      * match, *<c1p> and *<c2p> will be identical.
3277      *
3278      * If the target string is in UTF-8, the buffers pointed to by <c1_utf8>
3279      * and <c2_utf8> will contain the one or two UTF-8 sequences of bytes that
3280      * can match the beginning of <text_node>.  They should be declared with at
3281      * least length UTF8_MAXBYTES+1.  (If the target string isn't in UTF-8, it is
3282      * undefined what these contain.)  If one or both of the buffers are
3283      * invariant under UTF-8, *<c1p>, and *<c2p> will also be set to the
3284      * corresponding invariant.  If variant, the corresponding *<c1p> and/or
3285      * *<c2p> will be set to a negative number(s) that shouldn't match any code
3286      * point (unless inappropriately coerced to unsigned).   *<c1p> will equal
3287      * *<c2p> if and only if <c1_utf8> and <c2_utf8> are the same. */
3288 
3289     const bool utf8_target = PL_reg_match_utf8;
3290 
3291     UV c1 = CHRTEST_NOT_A_CP_1;
3292     UV c2 = CHRTEST_NOT_A_CP_2;
3293     bool use_chrtest_void = FALSE;
3294 
3295     /* Used when we have both utf8 input and utf8 output, to avoid converting
3296      * to/from code points */
3297     bool utf8_has_been_setup = FALSE;
3298 
3299     dVAR;
3300 
3301     U8 *pat = (U8*)STRING(text_node);
3302 
3303     if (OP(text_node) == EXACT) {
3304 
3305         /* In an exact node, only one thing can be matched, that first
3306          * character.  If both the pat and the target are UTF-8, we can just
3307          * copy the input to the output, avoiding finding the code point of
3308          * that character */
3309         if (!is_utf8_pat) {
3310             c2 = c1 = *pat;
3311         }
3312         else if (utf8_target) {
3313             Copy(pat, c1_utf8, UTF8SKIP(pat), U8);
3314             Copy(pat, c2_utf8, UTF8SKIP(pat), U8);
3315             utf8_has_been_setup = TRUE;
3316         }
3317         else {
3318             c2 = c1 = valid_utf8_to_uvchr(pat, NULL);
3319         }
3320     }
3321     else /* an EXACTFish node */
3322          if ((is_utf8_pat
3323                     && is_MULTI_CHAR_FOLD_utf8_safe(pat,
3324                                                     pat + STR_LEN(text_node)))
3325              || (!is_utf8_pat
3326                     && is_MULTI_CHAR_FOLD_latin1_safe(pat,
3327                                                     pat + STR_LEN(text_node))))
3328     {
3329         /* Multi-character folds require more context to sort out.  Also
3330          * PL_utf8_foldclosures used below doesn't handle them, so have to be
3331          * handled outside this routine */
3332         use_chrtest_void = TRUE;
3333     }
3334     else { /* an EXACTFish node which doesn't begin with a multi-char fold */
3335         c1 = is_utf8_pat ? valid_utf8_to_uvchr(pat, NULL) : *pat;
3336         if (c1 > 256) {
3337             /* Load the folds hash, if not already done */
3338             SV** listp;
3339             if (! PL_utf8_foldclosures) {
3340                 if (! PL_utf8_tofold) {
3341                     U8 dummy[UTF8_MAXBYTES+1];
3342 
3343                     /* Force loading this by folding an above-Latin1 char */
3344                     to_utf8_fold((U8*) HYPHEN_UTF8, dummy, NULL);
3345                     assert(PL_utf8_tofold); /* Verify that worked */
3346                 }
3347                 PL_utf8_foldclosures = _swash_inversion_hash(PL_utf8_tofold);
3348             }
3349 
3350             /* The fold closures data structure is a hash with the keys being
3351              * the UTF-8 of every character that is folded to, like 'k', and
3352              * the values each an array of all code points that fold to its
3353              * key.  e.g. [ 'k', 'K', KELVIN_SIGN ].  Multi-character folds are
3354              * not included */
3355             if ((! (listp = hv_fetch(PL_utf8_foldclosures,
3356                                      (char *) pat,
3357                                      UTF8SKIP(pat),
3358                                      FALSE))))
3359             {
3360                 /* Not found in the hash, therefore there are no folds
3361                  * containing it, so there is only a single character that
3362                  * could match */
3363                 c2 = c1;
3364             }
3365             else {  /* Does participate in folds */
3366                 AV* list = (AV*) *listp;
3367                 if (av_len(list) != 1) {
3368 
3369                     /* If there aren't exactly two folds to this, it is outside
3370                      * the scope of this function */
3371                     use_chrtest_void = TRUE;
3372                 }
3373                 else {  /* There are two.  Get them */
3374                     SV** c_p = av_fetch(list, 0, FALSE);
3375                     if (c_p == NULL) {
3376                         Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
3377                     }
3378                     c1 = SvUV(*c_p);
3379 
3380                     c_p = av_fetch(list, 1, FALSE);
3381                     if (c_p == NULL) {
3382                         Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
3383                     }
3384                     c2 = SvUV(*c_p);
3385 
3386                     /* Folds that cross the 255/256 boundary are forbidden if
3387                      * EXACTFL, or EXACTFA and one is ASCIII.  Since the
3388                      * pattern character is above 256, and its only other match
3389                      * is below 256, the only legal match will be to itself.
3390                      * We have thrown away the original, so have to compute
3391                      * which is the one above 255 */
3392                     if ((c1 < 256) != (c2 < 256)) {
3393                         if (OP(text_node) == EXACTFL
3394                             || (OP(text_node) == EXACTFA
3395                                 && (isASCII(c1) || isASCII(c2))))
3396                         {
3397                             if (c1 < 256) {
3398                                 c1 = c2;
3399                             }
3400                             else {
3401                                 c2 = c1;
3402                             }
3403                         }
3404                     }
3405                 }
3406             }
3407         }
3408         else /* Here, c1 is < 255 */
3409              if (utf8_target
3410                  && HAS_NONLATIN1_FOLD_CLOSURE(c1)
3411                  && OP(text_node) != EXACTFL
3412                  && (OP(text_node) != EXACTFA || ! isASCII(c1)))
3413         {
3414             /* Here, there could be something above Latin1 in the target which
3415              * folds to this character in the pattern.  All such cases except
3416              * LATIN SMALL LETTER Y WITH DIAERESIS have more than two characters
3417              * involved in their folds, so are outside the scope of this
3418              * function */
3419             if (UNLIKELY(c1 == LATIN_SMALL_LETTER_Y_WITH_DIAERESIS)) {
3420                 c2 = LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS;
3421             }
3422             else {
3423                 use_chrtest_void = TRUE;
3424             }
3425         }
3426         else { /* Here nothing above Latin1 can fold to the pattern character */
3427             switch (OP(text_node)) {
3428 
3429                 case EXACTFL:   /* /l rules */
3430                     c2 = PL_fold_locale[c1];
3431                     break;
3432 
3433                 case EXACTF:
3434                     if (! utf8_target) {    /* /d rules */
3435                         c2 = PL_fold[c1];
3436                         break;
3437                     }
3438                     /* FALLTHROUGH */
3439                     /* /u rules for all these.  This happens to work for
3440                      * EXACTFA as nothing in Latin1 folds to ASCII */
3441                 case EXACTFA:
3442                 case EXACTFU_TRICKYFOLD:
3443                 case EXACTFU_SS:
3444                 case EXACTFU:
3445                     c2 = PL_fold_latin1[c1];
3446                     break;
3447 
3448 		default:
3449                     Perl_croak(aTHX_ "panic: Unexpected op %u", OP(text_node));
3450                     assert(0); /* NOTREACHED */
3451             }
3452         }
3453     }
3454 
3455     /* Here have figured things out.  Set up the returns */
3456     if (use_chrtest_void) {
3457         *c2p = *c1p = CHRTEST_VOID;
3458     }
3459     else if (utf8_target) {
3460         if (! utf8_has_been_setup) {    /* Don't have the utf8; must get it */
3461             uvchr_to_utf8(c1_utf8, c1);
3462             uvchr_to_utf8(c2_utf8, c2);
3463         }
3464 
3465         /* Invariants are stored in both the utf8 and byte outputs; Use
3466          * negative numbers otherwise for the byte ones.  Make sure that the
3467          * byte ones are the same iff the utf8 ones are the same */
3468         *c1p = (UTF8_IS_INVARIANT(*c1_utf8)) ? *c1_utf8 : CHRTEST_NOT_A_CP_1;
3469         *c2p = (UTF8_IS_INVARIANT(*c2_utf8))
3470                 ? *c2_utf8
3471                 : (c1 == c2)
3472                   ? CHRTEST_NOT_A_CP_1
3473                   : CHRTEST_NOT_A_CP_2;
3474     }
3475     else if (c1 > 255) {
3476        if (c2 > 255) {  /* both possibilities are above what a non-utf8 string
3477                            can represent */
3478            return FALSE;
3479        }
3480 
3481        *c1p = *c2p = c2;    /* c2 is the only representable value */
3482     }
3483     else {  /* c1 is representable; see about c2 */
3484        *c1p = c1;
3485        *c2p = (c2 < 256) ? c2 : c1;
3486     }
3487 
3488     return TRUE;
3489 }
3490 
3491 /* returns -1 on failure, $+[0] on success */
3492 STATIC I32
3493 S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
3494 {
3495 #if PERL_VERSION < 9 && !defined(PERL_CORE)
3496     dMY_CXT;
3497 #endif
3498     dVAR;
3499     const bool utf8_target = PL_reg_match_utf8;
3500     const U32 uniflags = UTF8_ALLOW_DEFAULT;
3501     REGEXP *rex_sv = reginfo->prog;
3502     regexp *rex = ReANY(rex_sv);
3503     RXi_GET_DECL(rex,rexi);
3504     I32	oldsave;
3505     /* the current state. This is a cached copy of PL_regmatch_state */
3506     regmatch_state *st;
3507     /* cache heavy used fields of st in registers */
3508     regnode *scan;
3509     regnode *next;
3510     U32 n = 0;	/* general value; init to avoid compiler warning */
3511     I32 ln = 0; /* len or last;  init to avoid compiler warning */
3512     char *locinput = startpos;
3513     char *pushinput; /* where to continue after a PUSH */
3514     I32 nextchr;   /* is always set to UCHARAT(locinput) */
3515 
3516     bool result = 0;	    /* return value of S_regmatch */
3517     int depth = 0;	    /* depth of backtrack stack */
3518     U32 nochange_depth = 0; /* depth of GOSUB recursion with nochange */
3519     const U32 max_nochange_depth =
3520         (3 * rex->nparens > MAX_RECURSE_EVAL_NOCHANGE_DEPTH) ?
3521         3 * rex->nparens : MAX_RECURSE_EVAL_NOCHANGE_DEPTH;
3522     regmatch_state *yes_state = NULL; /* state to pop to on success of
3523 							    subpattern */
3524     /* mark_state piggy backs on the yes_state logic so that when we unwind
3525        the stack on success we can update the mark_state as we go */
3526     regmatch_state *mark_state = NULL; /* last mark state we have seen */
3527     regmatch_state *cur_eval = NULL; /* most recent EVAL_AB state */
3528     struct regmatch_state  *cur_curlyx = NULL; /* most recent curlyx */
3529     U32 state_num;
3530     bool no_final = 0;      /* prevent failure from backtracking? */
3531     bool do_cutgroup = 0;   /* no_final only until next branch/trie entry */
3532     char *startpoint = locinput;
3533     SV *popmark = NULL;     /* are we looking for a mark? */
3534     SV *sv_commit = NULL;   /* last mark name seen in failure */
3535     SV *sv_yes_mark = NULL; /* last mark name we have seen
3536                                during a successful match */
3537     U32 lastopen = 0;       /* last open we saw */
3538     bool has_cutgroup = RX_HAS_CUTGROUP(rex) ? 1 : 0;
3539     SV* const oreplsv = GvSV(PL_replgv);
3540     /* these three flags are set by various ops to signal information to
3541      * the very next op. They have a useful lifetime of exactly one loop
3542      * iteration, and are not preserved or restored by state pushes/pops
3543      */
3544     bool sw = 0;	    /* the condition value in (?(cond)a|b) */
3545     bool minmod = 0;	    /* the next "{n,m}" is a "{n,m}?" */
3546     int logical = 0;	    /* the following EVAL is:
3547 				0: (?{...})
3548 				1: (?(?{...})X|Y)
3549 				2: (??{...})
3550 			       or the following IFMATCH/UNLESSM is:
3551 			        false: plain (?=foo)
3552 				true:  used as a condition: (?(?=foo))
3553 			    */
3554     PAD* last_pad = NULL;
3555     dMULTICALL;
3556     I32 gimme = G_SCALAR;
3557     CV *caller_cv = NULL;	/* who called us */
3558     CV *last_pushed_cv = NULL;	/* most recently called (?{}) CV */
3559     CHECKPOINT runops_cp;	/* savestack position before executing EVAL */
3560     U32 maxopenparen = 0;       /* max '(' index seen so far */
3561     int to_complement;  /* Invert the result? */
3562     _char_class_number classnum;
3563     bool is_utf8_pat = reginfo->is_utf8_pat;
3564 
3565 #ifdef DEBUGGING
3566     GET_RE_DEBUG_FLAGS_DECL;
3567 #endif
3568 
3569     /* shut up 'may be used uninitialized' compiler warnings for dMULTICALL */
3570     multicall_oldcatch = 0;
3571     multicall_cv = NULL;
3572     cx = NULL;
3573     PERL_UNUSED_VAR(multicall_cop);
3574     PERL_UNUSED_VAR(newsp);
3575 
3576 
3577     PERL_ARGS_ASSERT_REGMATCH;
3578 
3579     DEBUG_OPTIMISE_r( DEBUG_EXECUTE_r({
3580 	    PerlIO_printf(Perl_debug_log,"regmatch start\n");
3581     }));
3582     /* on first ever call to regmatch, allocate first slab */
3583     if (!PL_regmatch_slab) {
3584 	Newx(PL_regmatch_slab, 1, regmatch_slab);
3585 	PL_regmatch_slab->prev = NULL;
3586 	PL_regmatch_slab->next = NULL;
3587 	PL_regmatch_state = SLAB_FIRST(PL_regmatch_slab);
3588     }
3589 
3590     oldsave = PL_savestack_ix;
3591     SAVEDESTRUCTOR_X(S_clear_backtrack_stack, NULL);
3592     SAVEVPTR(PL_regmatch_slab);
3593     SAVEVPTR(PL_regmatch_state);
3594 
3595     /* grab next free state slot */
3596     st = ++PL_regmatch_state;
3597     if (st >  SLAB_LAST(PL_regmatch_slab))
3598 	st = PL_regmatch_state = S_push_slab(aTHX);
3599 
3600     /* Note that nextchr is a byte even in UTF */
3601     SET_nextchr;
3602     scan = prog;
3603     while (scan != NULL) {
3604 
3605         DEBUG_EXECUTE_r( {
3606 	    SV * const prop = sv_newmortal();
3607 	    regnode *rnext=regnext(scan);
3608 	    DUMP_EXEC_POS( locinput, scan, utf8_target );
3609 	    regprop(rex, prop, scan);
3610 
3611 	    PerlIO_printf(Perl_debug_log,
3612 		    "%3"IVdf":%*s%s(%"IVdf")\n",
3613 		    (IV)(scan - rexi->program), depth*2, "",
3614 		    SvPVX_const(prop),
3615 		    (PL_regkind[OP(scan)] == END || !rnext) ?
3616 		        0 : (IV)(rnext - rexi->program));
3617 	});
3618 
3619 	next = scan + NEXT_OFF(scan);
3620 	if (next == scan)
3621 	    next = NULL;
3622 	state_num = OP(scan);
3623 
3624       reenter_switch:
3625         to_complement = 0;
3626 
3627         SET_nextchr;
3628         assert(nextchr < 256 && (nextchr >= 0 || nextchr == NEXTCHR_EOS));
3629 
3630 	switch (state_num) {
3631 	case BOL: /*  /^../  */
3632 	    if (locinput == PL_bostr)
3633 	    {
3634 		/* reginfo->till = reginfo->bol; */
3635 		break;
3636 	    }
3637 	    sayNO;
3638 
3639 	case MBOL: /*  /^../m  */
3640 	    if (locinput == PL_bostr ||
3641 		(!NEXTCHR_IS_EOS && locinput[-1] == '\n'))
3642 	    {
3643 		break;
3644 	    }
3645 	    sayNO;
3646 
3647 	case SBOL: /*  /^../s  */
3648 	    if (locinput == PL_bostr)
3649 		break;
3650 	    sayNO;
3651 
3652 	case GPOS: /*  \G  */
3653 	    if (locinput == reginfo->ganch)
3654 		break;
3655 	    sayNO;
3656 
3657 	case KEEPS: /*   \K  */
3658 	    /* update the startpoint */
3659 	    st->u.keeper.val = rex->offs[0].start;
3660 	    rex->offs[0].start = locinput - PL_bostr;
3661 	    PUSH_STATE_GOTO(KEEPS_next, next, locinput);
3662 	    assert(0); /*NOTREACHED*/
3663 	case KEEPS_next_fail:
3664 	    /* rollback the start point change */
3665 	    rex->offs[0].start = st->u.keeper.val;
3666 	    sayNO_SILENT;
3667 	    assert(0); /*NOTREACHED*/
3668 
3669 	case EOL: /* /..$/  */
3670 		goto seol;
3671 
3672 	case MEOL: /* /..$/m  */
3673 	    if (!NEXTCHR_IS_EOS && nextchr != '\n')
3674 		sayNO;
3675 	    break;
3676 
3677 	case SEOL: /* /..$/s  */
3678 	  seol:
3679 	    if (!NEXTCHR_IS_EOS && nextchr != '\n')
3680 		sayNO;
3681 	    if (PL_regeol - locinput > 1)
3682 		sayNO;
3683 	    break;
3684 
3685 	case EOS: /*  \z  */
3686 	    if (!NEXTCHR_IS_EOS)
3687 		sayNO;
3688 	    break;
3689 
3690 	case SANY: /*  /./s  */
3691 	    if (NEXTCHR_IS_EOS)
3692 		sayNO;
3693             goto increment_locinput;
3694 
3695 	case CANY: /*  \C  */
3696 	    if (NEXTCHR_IS_EOS)
3697 		sayNO;
3698 	    locinput++;
3699 	    break;
3700 
3701 	case REG_ANY: /*  /./  */
3702 	    if ((NEXTCHR_IS_EOS) || nextchr == '\n')
3703 		sayNO;
3704             goto increment_locinput;
3705 
3706 
3707 #undef  ST
3708 #define ST st->u.trie
3709         case TRIEC: /* (ab|cd) with known charclass */
3710             /* In this case the charclass data is available inline so
3711                we can fail fast without a lot of extra overhead.
3712              */
3713             if(!NEXTCHR_IS_EOS && !ANYOF_BITMAP_TEST(scan, nextchr)) {
3714                 DEBUG_EXECUTE_r(
3715                     PerlIO_printf(Perl_debug_log,
3716                               "%*s  %sfailed to match trie start class...%s\n",
3717                               REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
3718                 );
3719                 sayNO_SILENT;
3720                 assert(0); /* NOTREACHED */
3721             }
3722             /* FALL THROUGH */
3723 	case TRIE:  /* (ab|cd)  */
3724 	    /* the basic plan of execution of the trie is:
3725 	     * At the beginning, run though all the states, and
3726 	     * find the longest-matching word. Also remember the position
3727 	     * of the shortest matching word. For example, this pattern:
3728 	     *    1  2 3 4    5
3729 	     *    ab|a|x|abcd|abc
3730 	     * when matched against the string "abcde", will generate
3731 	     * accept states for all words except 3, with the longest
3732 	     * matching word being 4, and the shortest being 2 (with
3733 	     * the position being after char 1 of the string).
3734 	     *
3735 	     * Then for each matching word, in word order (i.e. 1,2,4,5),
3736 	     * we run the remainder of the pattern; on each try setting
3737 	     * the current position to the character following the word,
3738 	     * returning to try the next word on failure.
3739 	     *
3740 	     * We avoid having to build a list of words at runtime by
3741 	     * using a compile-time structure, wordinfo[].prev, which
3742 	     * gives, for each word, the previous accepting word (if any).
3743 	     * In the case above it would contain the mappings 1->2, 2->0,
3744 	     * 3->0, 4->5, 5->1.  We can use this table to generate, from
3745 	     * the longest word (4 above), a list of all words, by
3746 	     * following the list of prev pointers; this gives us the
3747 	     * unordered list 4,5,1,2. Then given the current word we have
3748 	     * just tried, we can go through the list and find the
3749 	     * next-biggest word to try (so if we just failed on word 2,
3750 	     * the next in the list is 4).
3751 	     *
3752 	     * Since at runtime we don't record the matching position in
3753 	     * the string for each word, we have to work that out for
3754 	     * each word we're about to process. The wordinfo table holds
3755 	     * the character length of each word; given that we recorded
3756 	     * at the start: the position of the shortest word and its
3757 	     * length in chars, we just need to move the pointer the
3758 	     * difference between the two char lengths. Depending on
3759 	     * Unicode status and folding, that's cheap or expensive.
3760 	     *
3761 	     * This algorithm is optimised for the case where are only a
3762 	     * small number of accept states, i.e. 0,1, or maybe 2.
3763 	     * With lots of accepts states, and having to try all of them,
3764 	     * it becomes quadratic on number of accept states to find all
3765 	     * the next words.
3766 	     */
3767 
3768 	    {
3769                 /* what type of TRIE am I? (utf8 makes this contextual) */
3770                 DECL_TRIE_TYPE(scan);
3771 
3772                 /* what trie are we using right now */
3773 		reg_trie_data * const trie
3774         	    = (reg_trie_data*)rexi->data->data[ ARG( scan ) ];
3775 		HV * widecharmap = MUTABLE_HV(rexi->data->data[ ARG( scan ) + 1 ]);
3776                 U32 state = trie->startstate;
3777 
3778                 if (   trie->bitmap
3779                     && (NEXTCHR_IS_EOS || !TRIE_BITMAP_TEST(trie, nextchr)))
3780                 {
3781         	    if (trie->states[ state ].wordnum) {
3782         	         DEBUG_EXECUTE_r(
3783                             PerlIO_printf(Perl_debug_log,
3784                         	          "%*s  %smatched empty string...%s\n",
3785                         	          REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
3786                         );
3787 			if (!trie->jump)
3788 			    break;
3789         	    } else {
3790         	        DEBUG_EXECUTE_r(
3791                             PerlIO_printf(Perl_debug_log,
3792                         	          "%*s  %sfailed to match trie start class...%s\n",
3793                         	          REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
3794                         );
3795         	        sayNO_SILENT;
3796         	   }
3797                 }
3798 
3799             {
3800 		U8 *uc = ( U8* )locinput;
3801 
3802 		STRLEN len = 0;
3803 		STRLEN foldlen = 0;
3804 		U8 *uscan = (U8*)NULL;
3805 		U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
3806 		U32 charcount = 0; /* how many input chars we have matched */
3807 		U32 accepted = 0; /* have we seen any accepting states? */
3808 
3809 		ST.jump = trie->jump;
3810 		ST.me = scan;
3811 		ST.firstpos = NULL;
3812 		ST.longfold = FALSE; /* char longer if folded => it's harder */
3813 		ST.nextword = 0;
3814 
3815 		/* fully traverse the TRIE; note the position of the
3816 		   shortest accept state and the wordnum of the longest
3817 		   accept state */
3818 
3819 		while ( state && uc <= (U8*)PL_regeol ) {
3820                     U32 base = trie->states[ state ].trans.base;
3821                     UV uvc = 0;
3822                     U16 charid = 0;
3823 		    U16 wordnum;
3824                     wordnum = trie->states[ state ].wordnum;
3825 
3826 		    if (wordnum) { /* it's an accept state */
3827 			if (!accepted) {
3828 			    accepted = 1;
3829 			    /* record first match position */
3830 			    if (ST.longfold) {
3831 				ST.firstpos = (U8*)locinput;
3832 				ST.firstchars = 0;
3833 			    }
3834 			    else {
3835 				ST.firstpos = uc;
3836 				ST.firstchars = charcount;
3837 			    }
3838 			}
3839 			if (!ST.nextword || wordnum < ST.nextword)
3840 			    ST.nextword = wordnum;
3841 			ST.topword = wordnum;
3842 		    }
3843 
3844 		    DEBUG_TRIE_EXECUTE_r({
3845 		                DUMP_EXEC_POS( (char *)uc, scan, utf8_target );
3846 			        PerlIO_printf( Perl_debug_log,
3847 			            "%*s  %sState: %4"UVxf" Accepted: %c ",
3848 			            2+depth * 2, "", PL_colors[4],
3849 			            (UV)state, (accepted ? 'Y' : 'N'));
3850 		    });
3851 
3852 		    /* read a char and goto next state */
3853 		    if ( base && (foldlen || uc < (U8*)PL_regeol)) {
3854 			I32 offset;
3855 			REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc,
3856 					     uscan, len, uvc, charid, foldlen,
3857 					     foldbuf, uniflags);
3858 			charcount++;
3859 			if (foldlen>0)
3860 			    ST.longfold = TRUE;
3861 			if (charid &&
3862 			     ( ((offset =
3863 			      base + charid - 1 - trie->uniquecharcount)) >= 0)
3864 
3865 			     && ((U32)offset < trie->lasttrans)
3866 			     && trie->trans[offset].check == state)
3867 			{
3868 			    state = trie->trans[offset].next;
3869 			}
3870 			else {
3871 			    state = 0;
3872 			}
3873 			uc += len;
3874 
3875 		    }
3876 		    else {
3877 			state = 0;
3878 		    }
3879 		    DEBUG_TRIE_EXECUTE_r(
3880 		        PerlIO_printf( Perl_debug_log,
3881 		            "Charid:%3x CP:%4"UVxf" After State: %4"UVxf"%s\n",
3882 		            charid, uvc, (UV)state, PL_colors[5] );
3883 		    );
3884 		}
3885 		if (!accepted)
3886 		   sayNO;
3887 
3888 		/* calculate total number of accept states */
3889 		{
3890 		    U16 w = ST.topword;
3891 		    accepted = 0;
3892 		    while (w) {
3893 			w = trie->wordinfo[w].prev;
3894 			accepted++;
3895 		    }
3896 		    ST.accepted = accepted;
3897 		}
3898 
3899 		DEBUG_EXECUTE_r(
3900 		    PerlIO_printf( Perl_debug_log,
3901 			"%*s  %sgot %"IVdf" possible matches%s\n",
3902 			REPORT_CODE_OFF + depth * 2, "",
3903 			PL_colors[4], (IV)ST.accepted, PL_colors[5] );
3904 		);
3905 		goto trie_first_try; /* jump into the fail handler */
3906 	    }}
3907 	    assert(0); /* NOTREACHED */
3908 
3909 	case TRIE_next_fail: /* we failed - try next alternative */
3910         {
3911             U8 *uc;
3912             if ( ST.jump) {
3913                 REGCP_UNWIND(ST.cp);
3914                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
3915 	    }
3916 	    if (!--ST.accepted) {
3917 	        DEBUG_EXECUTE_r({
3918 		    PerlIO_printf( Perl_debug_log,
3919 			"%*s  %sTRIE failed...%s\n",
3920 			REPORT_CODE_OFF+depth*2, "",
3921 			PL_colors[4],
3922 			PL_colors[5] );
3923 		});
3924 		sayNO_SILENT;
3925 	    }
3926 	    {
3927 		/* Find next-highest word to process.  Note that this code
3928 		 * is O(N^2) per trie run (O(N) per branch), so keep tight */
3929 		U16 min = 0;
3930 		U16 word;
3931 		U16 const nextword = ST.nextword;
3932 		reg_trie_wordinfo * const wordinfo
3933 		    = ((reg_trie_data*)rexi->data->data[ARG(ST.me)])->wordinfo;
3934 		for (word=ST.topword; word; word=wordinfo[word].prev) {
3935 		    if (word > nextword && (!min || word < min))
3936 			min = word;
3937 		}
3938 		ST.nextword = min;
3939 	    }
3940 
3941           trie_first_try:
3942             if (do_cutgroup) {
3943                 do_cutgroup = 0;
3944                 no_final = 0;
3945             }
3946 
3947             if ( ST.jump) {
3948                 ST.lastparen = rex->lastparen;
3949                 ST.lastcloseparen = rex->lastcloseparen;
3950 	        REGCP_SET(ST.cp);
3951             }
3952 
3953 	    /* find start char of end of current word */
3954 	    {
3955 		U32 chars; /* how many chars to skip */
3956 		reg_trie_data * const trie
3957 		    = (reg_trie_data*)rexi->data->data[ARG(ST.me)];
3958 
3959 		assert((trie->wordinfo[ST.nextword].len - trie->prefixlen)
3960 			    >=  ST.firstchars);
3961 		chars = (trie->wordinfo[ST.nextword].len - trie->prefixlen)
3962 			    - ST.firstchars;
3963 		uc = ST.firstpos;
3964 
3965 		if (ST.longfold) {
3966 		    /* the hard option - fold each char in turn and find
3967 		     * its folded length (which may be different */
3968 		    U8 foldbuf[UTF8_MAXBYTES_CASE + 1];
3969 		    STRLEN foldlen;
3970 		    STRLEN len;
3971 		    UV uvc;
3972 		    U8 *uscan;
3973 
3974 		    while (chars) {
3975 			if (utf8_target) {
3976 			    uvc = utf8n_to_uvuni((U8*)uc, UTF8_MAXLEN, &len,
3977 						    uniflags);
3978 			    uc += len;
3979 			}
3980 			else {
3981 			    uvc = *uc;
3982 			    uc++;
3983 			}
3984 			uvc = to_uni_fold(uvc, foldbuf, &foldlen);
3985 			uscan = foldbuf;
3986 			while (foldlen) {
3987 			    if (!--chars)
3988 				break;
3989 			    uvc = utf8n_to_uvuni(uscan, UTF8_MAXLEN, &len,
3990 					    uniflags);
3991 			    uscan += len;
3992 			    foldlen -= len;
3993 			}
3994 		    }
3995 		}
3996 		else {
3997 		    if (utf8_target)
3998 			while (chars--)
3999 			    uc += UTF8SKIP(uc);
4000 		    else
4001 			uc += chars;
4002 		}
4003 	    }
4004 
4005 	    scan = ST.me + ((ST.jump && ST.jump[ST.nextword])
4006 			    ? ST.jump[ST.nextword]
4007 			    : NEXT_OFF(ST.me));
4008 
4009 	    DEBUG_EXECUTE_r({
4010 		PerlIO_printf( Perl_debug_log,
4011 		    "%*s  %sTRIE matched word #%d, continuing%s\n",
4012 		    REPORT_CODE_OFF+depth*2, "",
4013 		    PL_colors[4],
4014 		    ST.nextword,
4015 		    PL_colors[5]
4016 		    );
4017 	    });
4018 
4019 	    if (ST.accepted > 1 || has_cutgroup) {
4020 		PUSH_STATE_GOTO(TRIE_next, scan, (char*)uc);
4021 		assert(0); /* NOTREACHED */
4022 	    }
4023 	    /* only one choice left - just continue */
4024 	    DEBUG_EXECUTE_r({
4025 		AV *const trie_words
4026 		    = MUTABLE_AV(rexi->data->data[ARG(ST.me)+TRIE_WORDS_OFFSET]);
4027 		SV ** const tmp = av_fetch( trie_words,
4028 		    ST.nextword-1, 0 );
4029 		SV *sv= tmp ? sv_newmortal() : NULL;
4030 
4031 		PerlIO_printf( Perl_debug_log,
4032 		    "%*s  %sonly one match left, short-circuiting: #%d <%s>%s\n",
4033 		    REPORT_CODE_OFF+depth*2, "", PL_colors[4],
4034 		    ST.nextword,
4035 		    tmp ? pv_pretty(sv, SvPV_nolen_const(*tmp), SvCUR(*tmp), 0,
4036 			    PL_colors[0], PL_colors[1],
4037 			    (SvUTF8(*tmp) ? PERL_PV_ESCAPE_UNI : 0)|PERL_PV_ESCAPE_NONASCII
4038 			)
4039 		    : "not compiled under -Dr",
4040 		    PL_colors[5] );
4041 	    });
4042 
4043 	    locinput = (char*)uc;
4044 	    continue; /* execute rest of RE */
4045 	    assert(0); /* NOTREACHED */
4046         }
4047 #undef  ST
4048 
4049 	case EXACT: {            /*  /abc/        */
4050 	    char *s = STRING(scan);
4051 	    ln = STR_LEN(scan);
4052 	    if (utf8_target != is_utf8_pat) {
4053 		/* The target and the pattern have differing utf8ness. */
4054 		char *l = locinput;
4055 		const char * const e = s + ln;
4056 
4057 		if (utf8_target) {
4058                     /* The target is utf8, the pattern is not utf8.
4059                      * Above-Latin1 code points can't match the pattern;
4060                      * invariants match exactly, and the other Latin1 ones need
4061                      * to be downgraded to a single byte in order to do the
4062                      * comparison.  (If we could be confident that the target
4063                      * is not malformed, this could be refactored to have fewer
4064                      * tests by just assuming that if the first bytes match, it
4065                      * is an invariant, but there are tests in the test suite
4066                      * dealing with (??{...}) which violate this) */
4067 		    while (s < e) {
4068 			if (l >= PL_regeol || UTF8_IS_ABOVE_LATIN1(* (U8*) l)) {
4069                             sayNO;
4070                         }
4071                         if (UTF8_IS_INVARIANT(*(U8*)l)) {
4072 			    if (*l != *s) {
4073                                 sayNO;
4074                             }
4075                             l++;
4076                         }
4077                         else {
4078                             if (TWO_BYTE_UTF8_TO_UNI(*l, *(l+1)) != * (U8*) s) {
4079                                 sayNO;
4080                             }
4081                             l += 2;
4082                         }
4083 			s++;
4084 		    }
4085 		}
4086 		else {
4087 		    /* The target is not utf8, the pattern is utf8. */
4088 		    while (s < e) {
4089                         if (l >= PL_regeol || UTF8_IS_ABOVE_LATIN1(* (U8*) s))
4090                         {
4091                             sayNO;
4092                         }
4093                         if (UTF8_IS_INVARIANT(*(U8*)s)) {
4094 			    if (*s != *l) {
4095                                 sayNO;
4096                             }
4097                             s++;
4098                         }
4099                         else {
4100                             if (TWO_BYTE_UTF8_TO_UNI(*s, *(s+1)) != * (U8*) l) {
4101                                 sayNO;
4102                             }
4103                             s += 2;
4104                         }
4105 			l++;
4106 		    }
4107 		}
4108 		locinput = l;
4109 	    }
4110             else {
4111                 /* The target and the pattern have the same utf8ness. */
4112                 /* Inline the first character, for speed. */
4113                 if (PL_regeol - locinput < ln
4114                     || UCHARAT(s) != nextchr
4115                     || (ln > 1 && memNE(s, locinput, ln)))
4116                 {
4117                     sayNO;
4118                 }
4119                 locinput += ln;
4120             }
4121 	    break;
4122 	    }
4123 
4124 	case EXACTFL: {          /*  /abc/il      */
4125 	    re_fold_t folder;
4126 	    const U8 * fold_array;
4127 	    const char * s;
4128 	    U32 fold_utf8_flags;
4129 
4130             RX_MATCH_TAINTED_on(reginfo->prog);
4131             folder = foldEQ_locale;
4132             fold_array = PL_fold_locale;
4133 	    fold_utf8_flags = FOLDEQ_UTF8_LOCALE;
4134 	    goto do_exactf;
4135 
4136 	case EXACTFU_SS:         /*  /\x{df}/iu   */
4137 	case EXACTFU_TRICKYFOLD: /*  /\x{390}/iu  */
4138 	case EXACTFU:            /*  /abc/iu      */
4139 	    folder = foldEQ_latin1;
4140 	    fold_array = PL_fold_latin1;
4141 	    fold_utf8_flags = is_utf8_pat ? FOLDEQ_S1_ALREADY_FOLDED : 0;
4142 	    goto do_exactf;
4143 
4144 	case EXACTFA:            /*  /abc/iaa     */
4145 	    folder = foldEQ_latin1;
4146 	    fold_array = PL_fold_latin1;
4147 	    fold_utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
4148 	    goto do_exactf;
4149 
4150 	case EXACTF:             /*  /abc/i       */
4151 	    folder = foldEQ;
4152 	    fold_array = PL_fold;
4153 	    fold_utf8_flags = 0;
4154 
4155 	  do_exactf:
4156 	    s = STRING(scan);
4157 	    ln = STR_LEN(scan);
4158 
4159 	    if (utf8_target || is_utf8_pat || state_num == EXACTFU_SS) {
4160 	      /* Either target or the pattern are utf8, or has the issue where
4161 	       * the fold lengths may differ. */
4162 		const char * const l = locinput;
4163 		char *e = PL_regeol;
4164 
4165 		if (! foldEQ_utf8_flags(s, 0,  ln, is_utf8_pat,
4166 			                l, &e, 0,  utf8_target, fold_utf8_flags))
4167 		{
4168 		    sayNO;
4169 		}
4170 		locinput = e;
4171 		break;
4172 	    }
4173 
4174 	    /* Neither the target nor the pattern are utf8 */
4175 	    if (UCHARAT(s) != nextchr
4176                 && !NEXTCHR_IS_EOS
4177 		&& UCHARAT(s) != fold_array[nextchr])
4178 	    {
4179 		sayNO;
4180 	    }
4181 	    if (PL_regeol - locinput < ln)
4182 		sayNO;
4183 	    if (ln > 1 && ! folder(s, locinput, ln))
4184 		sayNO;
4185 	    locinput += ln;
4186 	    break;
4187 	}
4188 
4189 	/* XXX Could improve efficiency by separating these all out using a
4190 	 * macro or in-line function.  At that point regcomp.c would no longer
4191 	 * have to set the FLAGS fields of these */
4192 	case BOUNDL:  /*  /\b/l  */
4193 	case NBOUNDL: /*  /\B/l  */
4194             RX_MATCH_TAINTED_on(reginfo->prog);
4195 	    /* FALL THROUGH */
4196 	case BOUND:   /*  /\b/   */
4197 	case BOUNDU:  /*  /\b/u  */
4198 	case BOUNDA:  /*  /\b/a  */
4199 	case NBOUND:  /*  /\B/   */
4200 	case NBOUNDU: /*  /\B/u  */
4201 	case NBOUNDA: /*  /\B/a  */
4202 	    /* was last char in word? */
4203 	    if (utf8_target
4204 		&& FLAGS(scan) != REGEX_ASCII_RESTRICTED_CHARSET
4205 		&& FLAGS(scan) != REGEX_ASCII_MORE_RESTRICTED_CHARSET)
4206 	    {
4207 		if (locinput == PL_bostr)
4208 		    ln = '\n';
4209 		else {
4210 		    const U8 * const r = reghop3((U8*)locinput, -1, (U8*)PL_bostr);
4211 
4212 		    ln = utf8n_to_uvchr(r, UTF8SKIP(r), 0, uniflags);
4213 		}
4214 		if (FLAGS(scan) != REGEX_LOCALE_CHARSET) {
4215 		    ln = isWORDCHAR_uni(ln);
4216                     if (NEXTCHR_IS_EOS)
4217                         n = 0;
4218                     else {
4219                         LOAD_UTF8_CHARCLASS_ALNUM();
4220                         n = swash_fetch(PL_utf8_swash_ptrs[_CC_WORDCHAR], (U8*)locinput,
4221                                                                 utf8_target);
4222                     }
4223 		}
4224 		else {
4225 		    ln = isWORDCHAR_LC_uvchr(UNI_TO_NATIVE(ln));
4226 		    n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_LC_utf8((U8*)locinput);
4227 		}
4228 	    }
4229 	    else {
4230 
4231 		/* Here the string isn't utf8, or is utf8 and only ascii
4232 		 * characters are to match \w.  In the latter case looking at
4233 		 * the byte just prior to the current one may be just the final
4234 		 * byte of a multi-byte character.  This is ok.  There are two
4235 		 * cases:
4236 		 * 1) it is a single byte character, and then the test is doing
4237 		 *	just what it's supposed to.
4238 		 * 2) it is a multi-byte character, in which case the final
4239 		 *	byte is never mistakable for ASCII, and so the test
4240 		 *	will say it is not a word character, which is the
4241 		 *	correct answer. */
4242 		ln = (locinput != PL_bostr) ?
4243 		    UCHARAT(locinput - 1) : '\n';
4244 		switch (FLAGS(scan)) {
4245 		    case REGEX_UNICODE_CHARSET:
4246 			ln = isWORDCHAR_L1(ln);
4247 			n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_L1(nextchr);
4248 			break;
4249 		    case REGEX_LOCALE_CHARSET:
4250 			ln = isWORDCHAR_LC(ln);
4251 			n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_LC(nextchr);
4252 			break;
4253 		    case REGEX_DEPENDS_CHARSET:
4254 			ln = isWORDCHAR(ln);
4255 			n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR(nextchr);
4256 			break;
4257 		    case REGEX_ASCII_RESTRICTED_CHARSET:
4258 		    case REGEX_ASCII_MORE_RESTRICTED_CHARSET:
4259 			ln = isWORDCHAR_A(ln);
4260 			n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_A(nextchr);
4261 			break;
4262 		    default:
4263 			Perl_croak(aTHX_ "panic: Unexpected FLAGS %u in op %u", FLAGS(scan), OP(scan));
4264 			break;
4265 		}
4266 	    }
4267 	    /* Note requires that all BOUNDs be lower than all NBOUNDs in
4268 	     * regcomp.sym */
4269 	    if (((!ln) == (!n)) == (OP(scan) < NBOUND))
4270 		    sayNO;
4271 	    break;
4272 
4273 	case ANYOF:  /*  /[abc]/       */
4274 	case ANYOF_WARN_SUPER:
4275             if (NEXTCHR_IS_EOS)
4276                 sayNO;
4277 	    if (utf8_target) {
4278 	        if (!reginclass(rex, scan, (U8*)locinput, utf8_target))
4279 		    sayNO;
4280 		locinput += UTF8SKIP(locinput);
4281 	    }
4282 	    else {
4283 		if (!REGINCLASS(rex, scan, (U8*)locinput))
4284 		    sayNO;
4285 		locinput++;
4286 	    }
4287 	    break;
4288 
4289         /* The argument (FLAGS) to all the POSIX node types is the class number
4290          * */
4291 
4292         case NPOSIXL:   /* \W or [:^punct:] etc. under /l */
4293             to_complement = 1;
4294             /* FALLTHROUGH */
4295 
4296         case POSIXL:    /* \w or [:punct:] etc. under /l */
4297             if (NEXTCHR_IS_EOS)
4298                 sayNO;
4299 
4300             /* The locale hasn't influenced the outcome before this, so defer
4301              * tainting until now */
4302             RX_MATCH_TAINTED_on(reginfo->prog);
4303 
4304             /* Use isFOO_lc() for characters within Latin1.  (Note that
4305              * UTF8_IS_INVARIANT works even on non-UTF-8 strings, or else
4306              * wouldn't be invariant) */
4307             if (UTF8_IS_INVARIANT(nextchr) || ! utf8_target) {
4308                 if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan), (U8) nextchr)))) {
4309                     sayNO;
4310                 }
4311             }
4312             else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
4313                 if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan),
4314                                         (U8) TWO_BYTE_UTF8_TO_UNI(nextchr,
4315                                                             *(locinput + 1))))))
4316                 {
4317                     sayNO;
4318                 }
4319             }
4320             else { /* Here, must be an above Latin-1 code point */
4321                 goto utf8_posix_not_eos;
4322             }
4323 
4324             /* Here, must be utf8 */
4325             locinput += UTF8SKIP(locinput);
4326             break;
4327 
4328         case NPOSIXD:   /* \W or [:^punct:] etc. under /d */
4329             to_complement = 1;
4330             /* FALLTHROUGH */
4331 
4332         case POSIXD:    /* \w or [:punct:] etc. under /d */
4333             if (utf8_target) {
4334                 goto utf8_posix;
4335             }
4336             goto posixa;
4337 
4338         case NPOSIXA:   /* \W or [:^punct:] etc. under /a */
4339 
4340             if (NEXTCHR_IS_EOS) {
4341                 sayNO;
4342             }
4343 
4344             /* All UTF-8 variants match */
4345             if (! UTF8_IS_INVARIANT(nextchr)) {
4346                 goto increment_locinput;
4347             }
4348 
4349             to_complement = 1;
4350             /* FALLTHROUGH */
4351 
4352         case POSIXA:    /* \w or [:punct:] etc. under /a */
4353 
4354           posixa:
4355             /* We get here through POSIXD, NPOSIXD, and NPOSIXA when not in
4356              * UTF-8, and also from NPOSIXA even in UTF-8 when the current
4357              * character is a single byte */
4358 
4359             if (NEXTCHR_IS_EOS
4360                 || ! (to_complement ^ cBOOL(_generic_isCC_A(nextchr,
4361                                                             FLAGS(scan)))))
4362             {
4363                 sayNO;
4364             }
4365 
4366             /* Here we are either not in utf8, or we matched a utf8-invariant,
4367              * so the next char is the next byte */
4368             locinput++;
4369             break;
4370 
4371         case NPOSIXU:   /* \W or [:^punct:] etc. under /u */
4372             to_complement = 1;
4373             /* FALLTHROUGH */
4374 
4375         case POSIXU:    /* \w or [:punct:] etc. under /u */
4376           utf8_posix:
4377             if (NEXTCHR_IS_EOS) {
4378                 sayNO;
4379             }
4380           utf8_posix_not_eos:
4381 
4382             /* Use _generic_isCC() for characters within Latin1.  (Note that
4383              * UTF8_IS_INVARIANT works even on non-UTF-8 strings, or else
4384              * wouldn't be invariant) */
4385             if (UTF8_IS_INVARIANT(nextchr) || ! utf8_target) {
4386                 if (! (to_complement ^ cBOOL(_generic_isCC(nextchr,
4387                                                            FLAGS(scan)))))
4388                 {
4389                     sayNO;
4390                 }
4391                 locinput++;
4392             }
4393             else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
4394                 if (! (to_complement
4395                        ^ cBOOL(_generic_isCC(TWO_BYTE_UTF8_TO_UNI(nextchr,
4396                                                                *(locinput + 1)),
4397                                               FLAGS(scan)))))
4398                 {
4399                     sayNO;
4400                 }
4401                 locinput += 2;
4402             }
4403             else {  /* Handle above Latin-1 code points */
4404                 classnum = (_char_class_number) FLAGS(scan);
4405                 if (classnum < _FIRST_NON_SWASH_CC) {
4406 
4407                     /* Here, uses a swash to find such code points.  Load if if
4408                      * not done already */
4409                     if (! PL_utf8_swash_ptrs[classnum]) {
4410                         U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
4411                         PL_utf8_swash_ptrs[classnum]
4412                                 = _core_swash_init("utf8",
4413                                         swash_property_names[classnum],
4414                                         &PL_sv_undef, 1, 0, NULL, &flags);
4415                     }
4416                     if (! (to_complement
4417                            ^ cBOOL(swash_fetch(PL_utf8_swash_ptrs[classnum],
4418                                                (U8 *) locinput, TRUE))))
4419                     {
4420                         sayNO;
4421                     }
4422                 }
4423                 else {  /* Here, uses macros to find above Latin-1 code points */
4424                     switch (classnum) {
4425                         case _CC_ENUM_SPACE:    /* XXX would require separate
4426                                                    code if we revert the change
4427                                                    of \v matching this */
4428                         case _CC_ENUM_PSXSPC:
4429                             if (! (to_complement
4430                                         ^ cBOOL(is_XPERLSPACE_high(locinput))))
4431                             {
4432                                 sayNO;
4433                             }
4434                             break;
4435                         case _CC_ENUM_BLANK:
4436                             if (! (to_complement
4437                                             ^ cBOOL(is_HORIZWS_high(locinput))))
4438                             {
4439                                 sayNO;
4440                             }
4441                             break;
4442                         case _CC_ENUM_XDIGIT:
4443                             if (! (to_complement
4444                                             ^ cBOOL(is_XDIGIT_high(locinput))))
4445                             {
4446                                 sayNO;
4447                             }
4448                             break;
4449                         case _CC_ENUM_VERTSPACE:
4450                             if (! (to_complement
4451                                             ^ cBOOL(is_VERTWS_high(locinput))))
4452                             {
4453                                 sayNO;
4454                             }
4455                             break;
4456                         default:    /* The rest, e.g. [:cntrl:], can't match
4457                                        above Latin1 */
4458                             if (! to_complement) {
4459                                 sayNO;
4460                             }
4461                             break;
4462                     }
4463                 }
4464                 locinput += UTF8SKIP(locinput);
4465             }
4466             break;
4467 
4468 	case CLUMP: /* Match \X: logical Unicode character.  This is defined as
4469 		       a Unicode extended Grapheme Cluster */
4470 	    /* From http://www.unicode.org/reports/tr29 (5.2 version).  An
4471 	      extended Grapheme Cluster is:
4472 
4473             CR LF
4474             | Prepend* Begin Extend*
4475             | .
4476 
4477             Begin is:           ( Special_Begin | ! Control )
4478             Special_Begin is:   ( Regional-Indicator+ | Hangul-syllable )
4479             Extend is:          ( Grapheme_Extend | Spacing_Mark )
4480             Control is:         [ GCB_Control | CR | LF ]
4481             Hangul-syllable is: ( T+ | ( L* ( L | ( LVT | ( V | LV ) V* ) T* ) ))
4482 
4483                If we create a 'Regular_Begin' = Begin - Special_Begin, then
4484                we can rewrite
4485 
4486                    Begin is ( Regular_Begin + Special Begin )
4487 
4488                It turns out that 98.4% of all Unicode code points match
4489                Regular_Begin.  Doing it this way eliminates a table match in
4490                the previous implementation for almost all Unicode code points.
4491 
4492 	       There is a subtlety with Prepend* which showed up in testing.
4493 	       Note that the Begin, and only the Begin is required in:
4494 	        | Prepend* Begin Extend*
4495 	       Also, Begin contains '! Control'.  A Prepend must be a
4496 	       '!  Control', which means it must also be a Begin.  What it
4497 	       comes down to is that if we match Prepend* and then find no
4498 	       suitable Begin afterwards, that if we backtrack the last
4499 	       Prepend, that one will be a suitable Begin.
4500 	    */
4501 
4502 	    if (NEXTCHR_IS_EOS)
4503 		sayNO;
4504 	    if  (! utf8_target) {
4505 
4506 		/* Match either CR LF  or '.', as all the other possibilities
4507 		 * require utf8 */
4508 		locinput++;	    /* Match the . or CR */
4509 		if (nextchr == '\r' /* And if it was CR, and the next is LF,
4510 				       match the LF */
4511 		    && locinput < PL_regeol
4512 		    && UCHARAT(locinput) == '\n')
4513                 {
4514                     locinput++;
4515                 }
4516 	    }
4517 	    else {
4518 
4519 		/* Utf8: See if is ( CR LF ); already know that locinput <
4520 		 * PL_regeol, so locinput+1 is in bounds */
4521 		if ( nextchr == '\r' && locinput+1 < PL_regeol
4522                      && UCHARAT(locinput + 1) == '\n')
4523                 {
4524 		    locinput += 2;
4525 		}
4526 		else {
4527                     STRLEN len;
4528 
4529 		    /* In case have to backtrack to beginning, then match '.' */
4530 		    char *starting = locinput;
4531 
4532 		    /* In case have to backtrack the last prepend */
4533 		    char *previous_prepend = NULL;
4534 
4535 		    LOAD_UTF8_CHARCLASS_GCB();
4536 
4537                     /* Match (prepend)*   */
4538                     while (locinput < PL_regeol
4539                            && (len = is_GCB_Prepend_utf8(locinput)))
4540                     {
4541                         previous_prepend = locinput;
4542                         locinput += len;
4543                     }
4544 
4545 		    /* As noted above, if we matched a prepend character, but
4546 		     * the next thing won't match, back off the last prepend we
4547 		     * matched, as it is guaranteed to match the begin */
4548 		    if (previous_prepend
4549 			&& (locinput >=  PL_regeol
4550 			    || (! swash_fetch(PL_utf8_X_regular_begin,
4551 					     (U8*)locinput, utf8_target)
4552 			         && ! is_GCB_SPECIAL_BEGIN_START_utf8(locinput)))
4553                         )
4554 		    {
4555 			locinput = previous_prepend;
4556 		    }
4557 
4558 		    /* Note that here we know PL_regeol > locinput, as we
4559 		     * tested that upon input to this switch case, and if we
4560 		     * moved locinput forward, we tested the result just above
4561 		     * and it either passed, or we backed off so that it will
4562 		     * now pass */
4563 		    if (swash_fetch(PL_utf8_X_regular_begin,
4564                                     (U8*)locinput, utf8_target)) {
4565                         locinput += UTF8SKIP(locinput);
4566                     }
4567                     else if (! is_GCB_SPECIAL_BEGIN_START_utf8(locinput)) {
4568 
4569 			/* Here did not match the required 'Begin' in the
4570 			 * second term.  So just match the very first
4571 			 * character, the '.' of the final term of the regex */
4572 			locinput = starting + UTF8SKIP(starting);
4573                         goto exit_utf8;
4574 		    } else {
4575 
4576                         /* Here is a special begin.  It can be composed of
4577                          * several individual characters.  One possibility is
4578                          * RI+ */
4579                         if ((len = is_GCB_RI_utf8(locinput))) {
4580                             locinput += len;
4581                             while (locinput < PL_regeol
4582                                    && (len = is_GCB_RI_utf8(locinput)))
4583                             {
4584                                 locinput += len;
4585                             }
4586                         } else if ((len = is_GCB_T_utf8(locinput))) {
4587                             /* Another possibility is T+ */
4588                             locinput += len;
4589                             while (locinput < PL_regeol
4590                                 && (len = is_GCB_T_utf8(locinput)))
4591                             {
4592                                 locinput += len;
4593                             }
4594                         } else {
4595 
4596                             /* Here, neither RI+ nor T+; must be some other
4597                              * Hangul.  That means it is one of the others: L,
4598                              * LV, LVT or V, and matches:
4599                              * L* (L | LVT T* | V * V* T* | LV  V* T*) */
4600 
4601                             /* Match L*           */
4602                             while (locinput < PL_regeol
4603                                    && (len = is_GCB_L_utf8(locinput)))
4604                             {
4605                                 locinput += len;
4606                             }
4607 
4608                             /* Here, have exhausted L*.  If the next character
4609                              * is not an LV, LVT nor V, it means we had to have
4610                              * at least one L, so matches L+ in the original
4611                              * equation, we have a complete hangul syllable.
4612                              * Are done. */
4613 
4614                             if (locinput < PL_regeol
4615                                 && is_GCB_LV_LVT_V_utf8(locinput))
4616                             {
4617                                 /* Otherwise keep going.  Must be LV, LVT or V.
4618                                  * See if LVT, by first ruling out V, then LV */
4619                                 if (! is_GCB_V_utf8(locinput)
4620                                         /* All but every TCount one is LV */
4621                                     && (valid_utf8_to_uvchr((U8 *) locinput,
4622                                                                          NULL)
4623                                                                         - SBASE)
4624                                         % TCount != 0)
4625                                 {
4626                                     locinput += UTF8SKIP(locinput);
4627                                 } else {
4628 
4629                                     /* Must be  V or LV.  Take it, then match
4630                                      * V*     */
4631                                     locinput += UTF8SKIP(locinput);
4632                                     while (locinput < PL_regeol
4633                                            && (len = is_GCB_V_utf8(locinput)))
4634                                     {
4635                                         locinput += len;
4636                                     }
4637                                 }
4638 
4639                                 /* And any of LV, LVT, or V can be followed
4640                                  * by T*            */
4641                                 while (locinput < PL_regeol
4642                                        && (len = is_GCB_T_utf8(locinput)))
4643                                 {
4644                                     locinput += len;
4645                                 }
4646                             }
4647                         }
4648                     }
4649 
4650                     /* Match any extender */
4651                     while (locinput < PL_regeol
4652                             && swash_fetch(PL_utf8_X_extend,
4653                                             (U8*)locinput, utf8_target))
4654                     {
4655                         locinput += UTF8SKIP(locinput);
4656                     }
4657 		}
4658             exit_utf8:
4659 		if (locinput > PL_regeol) sayNO;
4660 	    }
4661 	    break;
4662 
4663 	case NREFFL:  /*  /\g{name}/il  */
4664 	{   /* The capture buffer cases.  The ones beginning with N for the
4665 	       named buffers just convert to the equivalent numbered and
4666 	       pretend they were called as the corresponding numbered buffer
4667 	       op.  */
4668 	    /* don't initialize these in the declaration, it makes C++
4669 	       unhappy */
4670 	    char *s;
4671 	    char type;
4672 	    re_fold_t folder;
4673 	    const U8 *fold_array;
4674 	    UV utf8_fold_flags;
4675 
4676             RX_MATCH_TAINTED_on(reginfo->prog);
4677 	    folder = foldEQ_locale;
4678 	    fold_array = PL_fold_locale;
4679 	    type = REFFL;
4680 	    utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
4681 	    goto do_nref;
4682 
4683 	case NREFFA:  /*  /\g{name}/iaa  */
4684 	    folder = foldEQ_latin1;
4685 	    fold_array = PL_fold_latin1;
4686 	    type = REFFA;
4687 	    utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
4688 	    goto do_nref;
4689 
4690 	case NREFFU:  /*  /\g{name}/iu  */
4691 	    folder = foldEQ_latin1;
4692 	    fold_array = PL_fold_latin1;
4693 	    type = REFFU;
4694 	    utf8_fold_flags = 0;
4695 	    goto do_nref;
4696 
4697 	case NREFF:  /*  /\g{name}/i  */
4698 	    folder = foldEQ;
4699 	    fold_array = PL_fold;
4700 	    type = REFF;
4701 	    utf8_fold_flags = 0;
4702 	    goto do_nref;
4703 
4704 	case NREF:  /*  /\g{name}/   */
4705 	    type = REF;
4706 	    folder = NULL;
4707 	    fold_array = NULL;
4708 	    utf8_fold_flags = 0;
4709 	  do_nref:
4710 
4711 	    /* For the named back references, find the corresponding buffer
4712 	     * number */
4713 	    n = reg_check_named_buff_matched(rex,scan);
4714 
4715             if ( ! n ) {
4716                 sayNO;
4717 	    }
4718 	    goto do_nref_ref_common;
4719 
4720 	case REFFL:  /*  /\1/il  */
4721             RX_MATCH_TAINTED_on(reginfo->prog);
4722 	    folder = foldEQ_locale;
4723 	    fold_array = PL_fold_locale;
4724 	    utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
4725 	    goto do_ref;
4726 
4727 	case REFFA:  /*  /\1/iaa  */
4728 	    folder = foldEQ_latin1;
4729 	    fold_array = PL_fold_latin1;
4730 	    utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
4731 	    goto do_ref;
4732 
4733 	case REFFU:  /*  /\1/iu  */
4734 	    folder = foldEQ_latin1;
4735 	    fold_array = PL_fold_latin1;
4736 	    utf8_fold_flags = 0;
4737 	    goto do_ref;
4738 
4739 	case REFF:  /*  /\1/i  */
4740 	    folder = foldEQ;
4741 	    fold_array = PL_fold;
4742 	    utf8_fold_flags = 0;
4743 	    goto do_ref;
4744 
4745         case REF:  /*  /\1/    */
4746 	    folder = NULL;
4747 	    fold_array = NULL;
4748 	    utf8_fold_flags = 0;
4749 
4750 	  do_ref:
4751 	    type = OP(scan);
4752 	    n = ARG(scan);  /* which paren pair */
4753 
4754 	  do_nref_ref_common:
4755 	    ln = rex->offs[n].start;
4756 	    PL_reg_leftiter = PL_reg_maxiter;		/* Void cache */
4757 	    if (rex->lastparen < n || ln == -1)
4758 		sayNO;			/* Do not match unless seen CLOSEn. */
4759 	    if (ln == rex->offs[n].end)
4760 		break;
4761 
4762 	    s = PL_bostr + ln;
4763 	    if (type != REF	/* REF can do byte comparison */
4764 		&& (utf8_target || type == REFFU))
4765 	    { /* XXX handle REFFL better */
4766 		char * limit = PL_regeol;
4767 
4768 		/* This call case insensitively compares the entire buffer
4769 		    * at s, with the current input starting at locinput, but
4770 		    * not going off the end given by PL_regeol, and returns in
4771 		    * <limit> upon success, how much of the current input was
4772 		    * matched */
4773 		if (! foldEQ_utf8_flags(s, NULL, rex->offs[n].end - ln, utf8_target,
4774 				    locinput, &limit, 0, utf8_target, utf8_fold_flags))
4775 		{
4776 		    sayNO;
4777 		}
4778 		locinput = limit;
4779 		break;
4780 	    }
4781 
4782 	    /* Not utf8:  Inline the first character, for speed. */
4783 	    if (!NEXTCHR_IS_EOS &&
4784                 UCHARAT(s) != nextchr &&
4785 		(type == REF ||
4786 		 UCHARAT(s) != fold_array[nextchr]))
4787 		sayNO;
4788 	    ln = rex->offs[n].end - ln;
4789 	    if (locinput + ln > PL_regeol)
4790 		sayNO;
4791 	    if (ln > 1 && (type == REF
4792 			   ? memNE(s, locinput, ln)
4793 			   : ! folder(s, locinput, ln)))
4794 		sayNO;
4795 	    locinput += ln;
4796 	    break;
4797 	}
4798 
4799 	case NOTHING: /* null op; e.g. the 'nothing' following
4800                        * the '*' in m{(a+|b)*}' */
4801 	    break;
4802 	case TAIL: /* placeholder while compiling (A|B|C) */
4803 	    break;
4804 
4805 	case BACK: /* ??? doesn't appear to be used ??? */
4806 	    break;
4807 
4808 #undef  ST
4809 #define ST st->u.eval
4810 	{
4811 	    SV *ret;
4812 	    REGEXP *re_sv;
4813             regexp *re;
4814             regexp_internal *rei;
4815             regnode *startpoint;
4816 
4817 	case GOSTART: /*  (?R)  */
4818 	case GOSUB: /*    /(...(?1))/   /(...(?&foo))/   */
4819 	    if (cur_eval && cur_eval->locinput==locinput) {
4820                 if (cur_eval->u.eval.close_paren == (U32)ARG(scan))
4821                     Perl_croak(aTHX_ "Infinite recursion in regex");
4822                 if ( ++nochange_depth > max_nochange_depth )
4823                     Perl_croak(aTHX_
4824                         "Pattern subroutine nesting without pos change"
4825                         " exceeded limit in regex");
4826             } else {
4827                 nochange_depth = 0;
4828             }
4829 	    re_sv = rex_sv;
4830             re = rex;
4831             rei = rexi;
4832             if (OP(scan)==GOSUB) {
4833                 startpoint = scan + ARG2L(scan);
4834                 ST.close_paren = ARG(scan);
4835             } else {
4836                 startpoint = rei->program+1;
4837                 ST.close_paren = 0;
4838             }
4839             goto eval_recurse_doit;
4840             assert(0); /* NOTREACHED */
4841 
4842         case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */
4843             if (cur_eval && cur_eval->locinput==locinput) {
4844 		if ( ++nochange_depth > max_nochange_depth )
4845                     Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regex");
4846             } else {
4847                 nochange_depth = 0;
4848             }
4849 	    {
4850 		/* execute the code in the {...} */
4851 
4852 		dSP;
4853 		IV before;
4854 		OP * const oop = PL_op;
4855 		COP * const ocurcop = PL_curcop;
4856 		OP *nop;
4857 		char *saved_regeol = PL_regeol;
4858 		struct re_save_state saved_state;
4859 		CV *newcv;
4860 
4861 		/* save *all* paren positions */
4862 		regcppush(rex, 0, maxopenparen);
4863 		REGCP_SET(runops_cp);
4864 
4865 		/* To not corrupt the existing regex state while executing the
4866 		 * eval we would normally put it on the save stack, like with
4867 		 * save_re_context. However, re-evals have a weird scoping so we
4868 		 * can't just add ENTER/LEAVE here. With that, things like
4869 		 *
4870 		 *    (?{$a=2})(a(?{local$a=$a+1}))*aak*c(?{$b=$a})
4871 		 *
4872 		 * would break, as they expect the localisation to be unwound
4873 		 * only when the re-engine backtracks through the bit that
4874 		 * localised it.
4875 		 *
4876 		 * What we do instead is just saving the state in a local c
4877 		 * variable.
4878 		 */
4879 		Copy(&PL_reg_state, &saved_state, 1, struct re_save_state);
4880 
4881 		if (!caller_cv)
4882 		    caller_cv = find_runcv(NULL);
4883 
4884 		n = ARG(scan);
4885 
4886 		if (rexi->data->what[n] == 'r') { /* code from an external qr */
4887 		    newcv = (ReANY(
4888 						(REGEXP*)(rexi->data->data[n])
4889 					    ))->qr_anoncv
4890 					;
4891 		    nop = (OP*)rexi->data->data[n+1];
4892 		}
4893 		else if (rexi->data->what[n] == 'l') { /* literal code */
4894 		    newcv = caller_cv;
4895 		    nop = (OP*)rexi->data->data[n];
4896 		    assert(CvDEPTH(newcv));
4897 		}
4898 		else {
4899 		    /* literal with own CV */
4900 		    assert(rexi->data->what[n] == 'L');
4901 		    newcv = rex->qr_anoncv;
4902 		    nop = (OP*)rexi->data->data[n];
4903 		}
4904 
4905 		/* normally if we're about to execute code from the same
4906 		 * CV that we used previously, we just use the existing
4907 		 * CX stack entry. However, its possible that in the
4908 		 * meantime we may have backtracked, popped from the save
4909 		 * stack, and undone the SAVECOMPPAD(s) associated with
4910 		 * PUSH_MULTICALL; in which case PL_comppad no longer
4911 		 * points to newcv's pad. */
4912 		if (newcv != last_pushed_cv || PL_comppad != last_pad)
4913 		{
4914                     U8 flags = (CXp_SUB_RE |
4915                                 ((newcv == caller_cv) ? CXp_SUB_RE_FAKE : 0));
4916 		    if (last_pushed_cv) {
4917 			CHANGE_MULTICALL_FLAGS(newcv, flags);
4918 		    }
4919 		    else {
4920 			PUSH_MULTICALL_FLAGS(newcv, flags);
4921 		    }
4922 		    last_pushed_cv = newcv;
4923 		}
4924 		else {
4925                     /* these assignments are just to silence compiler
4926                      * warnings */
4927 		    multicall_cop = NULL;
4928 		    newsp = NULL;
4929 		}
4930 		last_pad = PL_comppad;
4931 
4932 		/* the initial nextstate you would normally execute
4933 		 * at the start of an eval (which would cause error
4934 		 * messages to come from the eval), may be optimised
4935 		 * away from the execution path in the regex code blocks;
4936 		 * so manually set PL_curcop to it initially */
4937 		{
4938 		    OP *o = cUNOPx(nop)->op_first;
4939 		    assert(o->op_type == OP_NULL);
4940 		    if (o->op_targ == OP_SCOPE) {
4941 			o = cUNOPo->op_first;
4942 		    }
4943 		    else {
4944 			assert(o->op_targ == OP_LEAVE);
4945 			o = cUNOPo->op_first;
4946 			assert(o->op_type == OP_ENTER);
4947 			o = o->op_sibling;
4948 		    }
4949 
4950 		    if (o->op_type != OP_STUB) {
4951 			assert(    o->op_type == OP_NEXTSTATE
4952 				|| o->op_type == OP_DBSTATE
4953 				|| (o->op_type == OP_NULL
4954 				    &&  (  o->op_targ == OP_NEXTSTATE
4955 					|| o->op_targ == OP_DBSTATE
4956 					)
4957 				    )
4958 			);
4959 			PL_curcop = (COP*)o;
4960 		    }
4961 		}
4962 		nop = nop->op_next;
4963 
4964 		DEBUG_STATE_r( PerlIO_printf(Perl_debug_log,
4965 		    "  re EVAL PL_op=0x%"UVxf"\n", PTR2UV(nop)) );
4966 
4967 		rex->offs[0].end = PL_reg_magic->mg_len = locinput - PL_bostr;
4968 
4969                 if (sv_yes_mark) {
4970                     SV *sv_mrk = get_sv("REGMARK", 1);
4971                     sv_setsv(sv_mrk, sv_yes_mark);
4972                 }
4973 
4974 		/* we don't use MULTICALL here as we want to call the
4975 		 * first op of the block of interest, rather than the
4976 		 * first op of the sub */
4977 		before = (IV)(SP-PL_stack_base);
4978 		PL_op = nop;
4979 		CALLRUNOPS(aTHX);			/* Scalar context. */
4980 		SPAGAIN;
4981 		if ((IV)(SP-PL_stack_base) == before)
4982 		    ret = &PL_sv_undef;   /* protect against empty (?{}) blocks. */
4983 		else {
4984 		    ret = POPs;
4985 		    PUTBACK;
4986 		}
4987 
4988 		/* before restoring everything, evaluate the returned
4989 		 * value, so that 'uninit' warnings don't use the wrong
4990 		 * PL_op or pad. Also need to process any magic vars
4991 		 * (e.g. $1) *before* parentheses are restored */
4992 
4993 		PL_op = NULL;
4994 
4995                 re_sv = NULL;
4996 		if (logical == 0)        /*   (?{})/   */
4997 		    sv_setsv(save_scalar(PL_replgv), ret); /* $^R */
4998 		else if (logical == 1) { /*   /(?(?{...})X|Y)/    */
4999 		    sw = cBOOL(SvTRUE(ret));
5000 		    logical = 0;
5001 		}
5002 		else {                   /*  /(??{})  */
5003 		    /*  if its overloaded, let the regex compiler handle
5004 		     *  it; otherwise extract regex, or stringify  */
5005 		    if (!SvAMAGIC(ret)) {
5006 			SV *sv = ret;
5007 			if (SvROK(sv))
5008 			    sv = SvRV(sv);
5009 			if (SvTYPE(sv) == SVt_REGEXP)
5010 			    re_sv = (REGEXP*) sv;
5011 			else if (SvSMAGICAL(sv)) {
5012 			    MAGIC *mg = mg_find(sv, PERL_MAGIC_qr);
5013 			    if (mg)
5014 				re_sv = (REGEXP *) mg->mg_obj;
5015 			}
5016 
5017 			/* force any magic, undef warnings here */
5018 			if (!re_sv) {
5019 			    ret = sv_mortalcopy(ret);
5020 			    (void) SvPV_force_nolen(ret);
5021 			}
5022 		    }
5023 
5024 		}
5025 
5026 		Copy(&saved_state, &PL_reg_state, 1, struct re_save_state);
5027 
5028 		/* *** Note that at this point we don't restore
5029 		 * PL_comppad, (or pop the CxSUB) on the assumption it may
5030 		 * be used again soon. This is safe as long as nothing
5031 		 * in the regexp code uses the pad ! */
5032 		PL_op = oop;
5033 		PL_curcop = ocurcop;
5034 		PL_regeol = saved_regeol;
5035 		S_regcp_restore(aTHX_ rex, runops_cp, &maxopenparen);
5036 
5037 		if (logical != 2)
5038 		    break;
5039 	    }
5040 
5041 		/* only /(??{})/  from now on */
5042 		logical = 0;
5043 		{
5044 		    /* extract RE object from returned value; compiling if
5045 		     * necessary */
5046 
5047 		    if (re_sv) {
5048 			re_sv = reg_temp_copy(NULL, re_sv);
5049 		    }
5050 		    else {
5051 			U32 pm_flags = 0;
5052 
5053 			if (SvUTF8(ret) && IN_BYTES) {
5054 			    /* In use 'bytes': make a copy of the octet
5055 			     * sequence, but without the flag on */
5056 			    STRLEN len;
5057 			    const char *const p = SvPV(ret, len);
5058 			    ret = newSVpvn_flags(p, len, SVs_TEMP);
5059 			}
5060 			if (rex->intflags & PREGf_USE_RE_EVAL)
5061 			    pm_flags |= PMf_USE_RE_EVAL;
5062 
5063 			/* if we got here, it should be an engine which
5064 			 * supports compiling code blocks and stuff */
5065 			assert(rex->engine && rex->engine->op_comp);
5066                         assert(!(scan->flags & ~RXf_PMf_COMPILETIME));
5067 			re_sv = rex->engine->op_comp(aTHX_ &ret, 1, NULL,
5068 				    rex->engine, NULL, NULL,
5069                                     /* copy /msix etc to inner pattern */
5070                                     scan->flags,
5071                                     pm_flags);
5072 
5073 			if (!(SvFLAGS(ret)
5074 			      & (SVs_TEMP | SVs_PADTMP | SVf_READONLY
5075 				 | SVs_GMG))) {
5076 			    /* This isn't a first class regexp. Instead, it's
5077 			       caching a regexp onto an existing, Perl visible
5078 			       scalar.  */
5079 			    sv_magic(ret, MUTABLE_SV(re_sv), PERL_MAGIC_qr, 0, 0);
5080 			}
5081 			/* safe to do now that any $1 etc has been
5082 			 * interpolated into the new pattern string and
5083 			 * compiled */
5084 			S_regcp_restore(aTHX_ rex, runops_cp, &maxopenparen);
5085 		    }
5086 		    SAVEFREESV(re_sv);
5087 		    re = ReANY(re_sv);
5088 		}
5089                 RXp_MATCH_COPIED_off(re);
5090                 re->subbeg = rex->subbeg;
5091                 re->sublen = rex->sublen;
5092                 re->suboffset = rex->suboffset;
5093                 re->subcoffset = rex->subcoffset;
5094 		rei = RXi_GET(re);
5095                 DEBUG_EXECUTE_r(
5096                     debug_start_match(re_sv, utf8_target, locinput, PL_regeol,
5097                         "Matching embedded");
5098 		);
5099 		startpoint = rei->program + 1;
5100                	ST.close_paren = 0; /* only used for GOSUB */
5101 
5102         eval_recurse_doit: /* Share code with GOSUB below this line */
5103 		/* run the pattern returned from (??{...}) */
5104 
5105                 /* Save *all* the positions. */
5106 		ST.cp = regcppush(rex, 0, maxopenparen);
5107 		REGCP_SET(ST.lastcp);
5108 
5109 		re->lastparen = 0;
5110 		re->lastcloseparen = 0;
5111 
5112 		maxopenparen = 0;
5113 
5114 		/* XXXX This is too dramatic a measure... */
5115 		PL_reg_maxiter = 0;
5116 
5117 		ST.saved_utf8_pat = is_utf8_pat;
5118 		is_utf8_pat = cBOOL(RX_UTF8(re_sv));
5119 
5120 		ST.prev_rex = rex_sv;
5121 		ST.prev_curlyx = cur_curlyx;
5122 		rex_sv = re_sv;
5123 		SET_reg_curpm(rex_sv);
5124 		rex = re;
5125 		rexi = rei;
5126 		cur_curlyx = NULL;
5127 		ST.B = next;
5128 		ST.prev_eval = cur_eval;
5129 		cur_eval = st;
5130 		/* now continue from first node in postoned RE */
5131 		PUSH_YES_STATE_GOTO(EVAL_AB, startpoint, locinput);
5132 		assert(0); /* NOTREACHED */
5133 	}
5134 
5135 	case EVAL_AB: /* cleanup after a successful (??{A})B */
5136 	    /* note: this is called twice; first after popping B, then A */
5137             is_utf8_pat = ST.saved_utf8_pat;
5138 	    rex_sv = ST.prev_rex;
5139 	    SET_reg_curpm(rex_sv);
5140 	    rex = ReANY(rex_sv);
5141 	    rexi = RXi_GET(rex);
5142 	    regcpblow(ST.cp);
5143 	    cur_eval = ST.prev_eval;
5144 	    cur_curlyx = ST.prev_curlyx;
5145 
5146 	    /* XXXX This is too dramatic a measure... */
5147 	    PL_reg_maxiter = 0;
5148             if ( nochange_depth )
5149 	        nochange_depth--;
5150 	    sayYES;
5151 
5152 
5153 	case EVAL_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
5154 	    /* note: this is called twice; first after popping B, then A */
5155             is_utf8_pat = ST.saved_utf8_pat;
5156 	    rex_sv = ST.prev_rex;
5157 	    SET_reg_curpm(rex_sv);
5158 	    rex = ReANY(rex_sv);
5159 	    rexi = RXi_GET(rex);
5160 
5161 	    REGCP_UNWIND(ST.lastcp);
5162 	    regcppop(rex, &maxopenparen);
5163 	    cur_eval = ST.prev_eval;
5164 	    cur_curlyx = ST.prev_curlyx;
5165 	    /* XXXX This is too dramatic a measure... */
5166 	    PL_reg_maxiter = 0;
5167 	    if ( nochange_depth )
5168 	        nochange_depth--;
5169 	    sayNO_SILENT;
5170 #undef ST
5171 
5172 	case OPEN: /*  (  */
5173 	    n = ARG(scan);  /* which paren pair */
5174 	    rex->offs[n].start_tmp = locinput - PL_bostr;
5175 	    if (n > maxopenparen)
5176 		maxopenparen = n;
5177 	    DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
5178 		"rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf" tmp; maxopenparen=%"UVuf"\n",
5179 		PTR2UV(rex),
5180 		PTR2UV(rex->offs),
5181 		(UV)n,
5182 		(IV)rex->offs[n].start_tmp,
5183 		(UV)maxopenparen
5184 	    ));
5185             lastopen = n;
5186 	    break;
5187 
5188 /* XXX really need to log other places start/end are set too */
5189 #define CLOSE_CAPTURE \
5190     rex->offs[n].start = rex->offs[n].start_tmp; \
5191     rex->offs[n].end = locinput - PL_bostr; \
5192     DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log, \
5193 	"rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf"..%"IVdf"\n", \
5194 	PTR2UV(rex), \
5195 	PTR2UV(rex->offs), \
5196 	(UV)n, \
5197 	(IV)rex->offs[n].start, \
5198 	(IV)rex->offs[n].end \
5199     ))
5200 
5201 	case CLOSE:  /*  )  */
5202 	    n = ARG(scan);  /* which paren pair */
5203 	    CLOSE_CAPTURE;
5204 	    if (n > rex->lastparen)
5205 		rex->lastparen = n;
5206 	    rex->lastcloseparen = n;
5207             if (cur_eval && cur_eval->u.eval.close_paren == n) {
5208 	        goto fake_end;
5209 	    }
5210 	    break;
5211 
5212         case ACCEPT:  /*  (*ACCEPT)  */
5213             if (ARG(scan)){
5214                 regnode *cursor;
5215                 for (cursor=scan;
5216                      cursor && OP(cursor)!=END;
5217                      cursor=regnext(cursor))
5218                 {
5219                     if ( OP(cursor)==CLOSE ){
5220                         n = ARG(cursor);
5221                         if ( n <= lastopen ) {
5222 			    CLOSE_CAPTURE;
5223                             if (n > rex->lastparen)
5224                                 rex->lastparen = n;
5225                             rex->lastcloseparen = n;
5226                             if ( n == ARG(scan) || (cur_eval &&
5227                                 cur_eval->u.eval.close_paren == n))
5228                                 break;
5229                         }
5230                     }
5231                 }
5232             }
5233 	    goto fake_end;
5234 	    /*NOTREACHED*/
5235 
5236 	case GROUPP:  /*  (?(1))  */
5237 	    n = ARG(scan);  /* which paren pair */
5238 	    sw = cBOOL(rex->lastparen >= n && rex->offs[n].end != -1);
5239 	    break;
5240 
5241 	case NGROUPP:  /*  (?(<name>))  */
5242 	    /* reg_check_named_buff_matched returns 0 for no match */
5243 	    sw = cBOOL(0 < reg_check_named_buff_matched(rex,scan));
5244 	    break;
5245 
5246         case INSUBP:   /*  (?(R))  */
5247             n = ARG(scan);
5248             sw = (cur_eval && (!n || cur_eval->u.eval.close_paren == n));
5249             break;
5250 
5251         case DEFINEP:  /*  (?(DEFINE))  */
5252             sw = 0;
5253             break;
5254 
5255 	case IFTHEN:   /*  (?(cond)A|B)  */
5256 	    PL_reg_leftiter = PL_reg_maxiter;		/* Void cache */
5257 	    if (sw)
5258 		next = NEXTOPER(NEXTOPER(scan));
5259 	    else {
5260 		next = scan + ARG(scan);
5261 		if (OP(next) == IFTHEN) /* Fake one. */
5262 		    next = NEXTOPER(NEXTOPER(next));
5263 	    }
5264 	    break;
5265 
5266 	case LOGICAL:  /* modifier for EVAL and IFMATCH */
5267 	    logical = scan->flags;
5268 	    break;
5269 
5270 /*******************************************************************
5271 
5272 The CURLYX/WHILEM pair of ops handle the most generic case of the /A*B/
5273 pattern, where A and B are subpatterns. (For simple A, CURLYM or
5274 STAR/PLUS/CURLY/CURLYN are used instead.)
5275 
5276 A*B is compiled as <CURLYX><A><WHILEM><B>
5277 
5278 On entry to the subpattern, CURLYX is called. This pushes a CURLYX
5279 state, which contains the current count, initialised to -1. It also sets
5280 cur_curlyx to point to this state, with any previous value saved in the
5281 state block.
5282 
5283 CURLYX then jumps straight to the WHILEM op, rather than executing A,
5284 since the pattern may possibly match zero times (i.e. it's a while {} loop
5285 rather than a do {} while loop).
5286 
5287 Each entry to WHILEM represents a successful match of A. The count in the
5288 CURLYX block is incremented, another WHILEM state is pushed, and execution
5289 passes to A or B depending on greediness and the current count.
5290 
5291 For example, if matching against the string a1a2a3b (where the aN are
5292 substrings that match /A/), then the match progresses as follows: (the
5293 pushed states are interspersed with the bits of strings matched so far):
5294 
5295     <CURLYX cnt=-1>
5296     <CURLYX cnt=0><WHILEM>
5297     <CURLYX cnt=1><WHILEM> a1 <WHILEM>
5298     <CURLYX cnt=2><WHILEM> a1 <WHILEM> a2 <WHILEM>
5299     <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM>
5300     <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM> b
5301 
5302 (Contrast this with something like CURLYM, which maintains only a single
5303 backtrack state:
5304 
5305     <CURLYM cnt=0> a1
5306     a1 <CURLYM cnt=1> a2
5307     a1 a2 <CURLYM cnt=2> a3
5308     a1 a2 a3 <CURLYM cnt=3> b
5309 )
5310 
5311 Each WHILEM state block marks a point to backtrack to upon partial failure
5312 of A or B, and also contains some minor state data related to that
5313 iteration.  The CURLYX block, pointed to by cur_curlyx, contains the
5314 overall state, such as the count, and pointers to the A and B ops.
5315 
5316 This is complicated slightly by nested CURLYX/WHILEM's. Since cur_curlyx
5317 must always point to the *current* CURLYX block, the rules are:
5318 
5319 When executing CURLYX, save the old cur_curlyx in the CURLYX state block,
5320 and set cur_curlyx to point the new block.
5321 
5322 When popping the CURLYX block after a successful or unsuccessful match,
5323 restore the previous cur_curlyx.
5324 
5325 When WHILEM is about to execute B, save the current cur_curlyx, and set it
5326 to the outer one saved in the CURLYX block.
5327 
5328 When popping the WHILEM block after a successful or unsuccessful B match,
5329 restore the previous cur_curlyx.
5330 
5331 Here's an example for the pattern (AI* BI)*BO
5332 I and O refer to inner and outer, C and W refer to CURLYX and WHILEM:
5333 
5334 cur_
5335 curlyx backtrack stack
5336 ------ ---------------
5337 NULL
5338 CO     <CO prev=NULL> <WO>
5339 CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai
5340 CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi
5341 NULL   <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi <WO prev=CO> bo
5342 
5343 At this point the pattern succeeds, and we work back down the stack to
5344 clean up, restoring as we go:
5345 
5346 CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi
5347 CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai
5348 CO     <CO prev=NULL> <WO>
5349 NULL
5350 
5351 *******************************************************************/
5352 
5353 #define ST st->u.curlyx
5354 
5355 	case CURLYX:    /* start of /A*B/  (for complex A) */
5356 	{
5357 	    /* No need to save/restore up to this paren */
5358 	    I32 parenfloor = scan->flags;
5359 
5360 	    assert(next); /* keep Coverity happy */
5361 	    if (OP(PREVOPER(next)) == NOTHING) /* LONGJMP */
5362 		next += ARG(next);
5363 
5364 	    /* XXXX Probably it is better to teach regpush to support
5365 	       parenfloor > maxopenparen ... */
5366 	    if (parenfloor > (I32)rex->lastparen)
5367 		parenfloor = rex->lastparen; /* Pessimization... */
5368 
5369 	    ST.prev_curlyx= cur_curlyx;
5370 	    cur_curlyx = st;
5371 	    ST.cp = PL_savestack_ix;
5372 
5373 	    /* these fields contain the state of the current curly.
5374 	     * they are accessed by subsequent WHILEMs */
5375 	    ST.parenfloor = parenfloor;
5376 	    ST.me = scan;
5377 	    ST.B = next;
5378 	    ST.minmod = minmod;
5379 	    minmod = 0;
5380 	    ST.count = -1;	/* this will be updated by WHILEM */
5381 	    ST.lastloc = NULL;  /* this will be updated by WHILEM */
5382 
5383 	    PUSH_YES_STATE_GOTO(CURLYX_end, PREVOPER(next), locinput);
5384 	    assert(0); /* NOTREACHED */
5385 	}
5386 
5387 	case CURLYX_end: /* just finished matching all of A*B */
5388 	    cur_curlyx = ST.prev_curlyx;
5389 	    sayYES;
5390 	    assert(0); /* NOTREACHED */
5391 
5392 	case CURLYX_end_fail: /* just failed to match all of A*B */
5393 	    regcpblow(ST.cp);
5394 	    cur_curlyx = ST.prev_curlyx;
5395 	    sayNO;
5396 	    assert(0); /* NOTREACHED */
5397 
5398 
5399 #undef ST
5400 #define ST st->u.whilem
5401 
5402 	case WHILEM:     /* just matched an A in /A*B/  (for complex A) */
5403 	{
5404 	    /* see the discussion above about CURLYX/WHILEM */
5405 	    I32 n;
5406 	    int min = ARG1(cur_curlyx->u.curlyx.me);
5407 	    int max = ARG2(cur_curlyx->u.curlyx.me);
5408 	    regnode *A = NEXTOPER(cur_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS;
5409 
5410 	    assert(cur_curlyx); /* keep Coverity happy */
5411 	    n = ++cur_curlyx->u.curlyx.count; /* how many A's matched */
5412 	    ST.save_lastloc = cur_curlyx->u.curlyx.lastloc;
5413 	    ST.cache_offset = 0;
5414 	    ST.cache_mask = 0;
5415 
5416 
5417 	    DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
5418 		  "%*s  whilem: matched %ld out of %d..%d\n",
5419 		  REPORT_CODE_OFF+depth*2, "", (long)n, min, max)
5420 	    );
5421 
5422 	    /* First just match a string of min A's. */
5423 
5424 	    if (n < min) {
5425 		ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
5426                                     maxopenparen);
5427 		cur_curlyx->u.curlyx.lastloc = locinput;
5428 		REGCP_SET(ST.lastcp);
5429 
5430 		PUSH_STATE_GOTO(WHILEM_A_pre, A, locinput);
5431 		assert(0); /* NOTREACHED */
5432 	    }
5433 
5434 	    /* If degenerate A matches "", assume A done. */
5435 
5436 	    if (locinput == cur_curlyx->u.curlyx.lastloc) {
5437 		DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
5438 		   "%*s  whilem: empty match detected, trying continuation...\n",
5439 		   REPORT_CODE_OFF+depth*2, "")
5440 		);
5441 		goto do_whilem_B_max;
5442 	    }
5443 
5444 	    /* super-linear cache processing */
5445 
5446 	    if (scan->flags) {
5447 
5448 		if (!PL_reg_maxiter) {
5449 		    /* start the countdown: Postpone detection until we
5450 		     * know the match is not *that* much linear. */
5451 		    PL_reg_maxiter = (PL_regeol - PL_bostr + 1) * (scan->flags>>4);
5452 		    /* possible overflow for long strings and many CURLYX's */
5453 		    if (PL_reg_maxiter < 0)
5454 			PL_reg_maxiter = I32_MAX;
5455 		    PL_reg_leftiter = PL_reg_maxiter;
5456 		}
5457 
5458 		if (PL_reg_leftiter-- == 0) {
5459 		    /* initialise cache */
5460 		    const I32 size = (PL_reg_maxiter + 7)/8;
5461 		    if (PL_reg_poscache) {
5462 			if ((I32)PL_reg_poscache_size < size) {
5463 			    Renew(PL_reg_poscache, size, char);
5464 			    PL_reg_poscache_size = size;
5465 			}
5466 			Zero(PL_reg_poscache, size, char);
5467 		    }
5468 		    else {
5469 			PL_reg_poscache_size = size;
5470 			Newxz(PL_reg_poscache, size, char);
5471 		    }
5472 		    DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
5473       "%swhilem: Detected a super-linear match, switching on caching%s...\n",
5474 			      PL_colors[4], PL_colors[5])
5475 		    );
5476 		}
5477 
5478 		if (PL_reg_leftiter < 0) {
5479 		    /* have we already failed at this position? */
5480 		    I32 offset, mask;
5481 		    offset  = (scan->flags & 0xf) - 1
5482 		  		+ (locinput - PL_bostr)  * (scan->flags>>4);
5483 		    mask    = 1 << (offset % 8);
5484 		    offset /= 8;
5485 		    if (PL_reg_poscache[offset] & mask) {
5486 			DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
5487 			    "%*s  whilem: (cache) already tried at this position...\n",
5488 			    REPORT_CODE_OFF+depth*2, "")
5489 			);
5490 			sayNO; /* cache records failure */
5491 		    }
5492 		    ST.cache_offset = offset;
5493 		    ST.cache_mask   = mask;
5494 		}
5495 	    }
5496 
5497 	    /* Prefer B over A for minimal matching. */
5498 
5499 	    if (cur_curlyx->u.curlyx.minmod) {
5500 		ST.save_curlyx = cur_curlyx;
5501 		cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
5502 		ST.cp = regcppush(rex, ST.save_curlyx->u.curlyx.parenfloor,
5503                             maxopenparen);
5504 		REGCP_SET(ST.lastcp);
5505 		PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B,
5506                                     locinput);
5507 		assert(0); /* NOTREACHED */
5508 	    }
5509 
5510 	    /* Prefer A over B for maximal matching. */
5511 
5512 	    if (n < max) { /* More greed allowed? */
5513 		ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
5514                             maxopenparen);
5515 		cur_curlyx->u.curlyx.lastloc = locinput;
5516 		REGCP_SET(ST.lastcp);
5517 		PUSH_STATE_GOTO(WHILEM_A_max, A, locinput);
5518 		assert(0); /* NOTREACHED */
5519 	    }
5520 	    goto do_whilem_B_max;
5521 	}
5522 	assert(0); /* NOTREACHED */
5523 
5524 	case WHILEM_B_min: /* just matched B in a minimal match */
5525 	case WHILEM_B_max: /* just matched B in a maximal match */
5526 	    cur_curlyx = ST.save_curlyx;
5527 	    sayYES;
5528 	    assert(0); /* NOTREACHED */
5529 
5530 	case WHILEM_B_max_fail: /* just failed to match B in a maximal match */
5531 	    cur_curlyx = ST.save_curlyx;
5532 	    cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
5533 	    cur_curlyx->u.curlyx.count--;
5534 	    CACHEsayNO;
5535 	    assert(0); /* NOTREACHED */
5536 
5537 	case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
5538 	    /* FALL THROUGH */
5539 	case WHILEM_A_pre_fail: /* just failed to match even minimal A */
5540 	    REGCP_UNWIND(ST.lastcp);
5541 	    regcppop(rex, &maxopenparen);
5542 	    cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
5543 	    cur_curlyx->u.curlyx.count--;
5544 	    CACHEsayNO;
5545 	    assert(0); /* NOTREACHED */
5546 
5547 	case WHILEM_A_max_fail: /* just failed to match A in a maximal match */
5548 	    REGCP_UNWIND(ST.lastcp);
5549 	    regcppop(rex, &maxopenparen); /* Restore some previous $<digit>s? */
5550 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
5551 		"%*s  whilem: failed, trying continuation...\n",
5552 		REPORT_CODE_OFF+depth*2, "")
5553 	    );
5554 	  do_whilem_B_max:
5555 	    if (cur_curlyx->u.curlyx.count >= REG_INFTY
5556 		&& ckWARN(WARN_REGEXP)
5557 		&& !reginfo->warned)
5558 	    {
5559                 reginfo->warned	= TRUE;
5560 		Perl_warner(aTHX_ packWARN(WARN_REGEXP),
5561 		     "Complex regular subexpression recursion limit (%d) "
5562 		     "exceeded",
5563 		     REG_INFTY - 1);
5564 	    }
5565 
5566 	    /* now try B */
5567 	    ST.save_curlyx = cur_curlyx;
5568 	    cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
5569 	    PUSH_YES_STATE_GOTO(WHILEM_B_max, ST.save_curlyx->u.curlyx.B,
5570                                 locinput);
5571 	    assert(0); /* NOTREACHED */
5572 
5573 	case WHILEM_B_min_fail: /* just failed to match B in a minimal match */
5574 	    cur_curlyx = ST.save_curlyx;
5575 	    REGCP_UNWIND(ST.lastcp);
5576 	    regcppop(rex, &maxopenparen);
5577 
5578 	    if (cur_curlyx->u.curlyx.count >= /*max*/ARG2(cur_curlyx->u.curlyx.me)) {
5579 		/* Maximum greed exceeded */
5580 		if (cur_curlyx->u.curlyx.count >= REG_INFTY
5581 		    && ckWARN(WARN_REGEXP)
5582                     && !reginfo->warned)
5583 		{
5584                     reginfo->warned	= TRUE;
5585 		    Perl_warner(aTHX_ packWARN(WARN_REGEXP),
5586 			"Complex regular subexpression recursion "
5587 			"limit (%d) exceeded",
5588 			REG_INFTY - 1);
5589 		}
5590 		cur_curlyx->u.curlyx.count--;
5591 		CACHEsayNO;
5592 	    }
5593 
5594 	    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
5595 		"%*s  trying longer...\n", REPORT_CODE_OFF+depth*2, "")
5596 	    );
5597 	    /* Try grabbing another A and see if it helps. */
5598 	    cur_curlyx->u.curlyx.lastloc = locinput;
5599 	    ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
5600                             maxopenparen);
5601 	    REGCP_SET(ST.lastcp);
5602 	    PUSH_STATE_GOTO(WHILEM_A_min,
5603 		/*A*/ NEXTOPER(ST.save_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS,
5604                 locinput);
5605 	    assert(0); /* NOTREACHED */
5606 
5607 #undef  ST
5608 #define ST st->u.branch
5609 
5610 	case BRANCHJ:	    /*  /(...|A|...)/ with long next pointer */
5611 	    next = scan + ARG(scan);
5612 	    if (next == scan)
5613 		next = NULL;
5614 	    scan = NEXTOPER(scan);
5615 	    /* FALL THROUGH */
5616 
5617 	case BRANCH:	    /*  /(...|A|...)/ */
5618 	    scan = NEXTOPER(scan); /* scan now points to inner node */
5619 	    ST.lastparen = rex->lastparen;
5620 	    ST.lastcloseparen = rex->lastcloseparen;
5621 	    ST.next_branch = next;
5622 	    REGCP_SET(ST.cp);
5623 
5624 	    /* Now go into the branch */
5625 	    if (has_cutgroup) {
5626 	        PUSH_YES_STATE_GOTO(BRANCH_next, scan, locinput);
5627 	    } else {
5628 	        PUSH_STATE_GOTO(BRANCH_next, scan, locinput);
5629 	    }
5630 	    assert(0); /* NOTREACHED */
5631 
5632         case CUTGROUP:  /*  /(*THEN)/  */
5633             sv_yes_mark = st->u.mark.mark_name = scan->flags ? NULL :
5634                 MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
5635             PUSH_STATE_GOTO(CUTGROUP_next, next, locinput);
5636             assert(0); /* NOTREACHED */
5637 
5638         case CUTGROUP_next_fail:
5639             do_cutgroup = 1;
5640             no_final = 1;
5641             if (st->u.mark.mark_name)
5642                 sv_commit = st->u.mark.mark_name;
5643             sayNO;
5644             assert(0); /* NOTREACHED */
5645 
5646         case BRANCH_next:
5647             sayYES;
5648             assert(0); /* NOTREACHED */
5649 
5650 	case BRANCH_next_fail: /* that branch failed; try the next, if any */
5651 	    if (do_cutgroup) {
5652 	        do_cutgroup = 0;
5653 	        no_final = 0;
5654 	    }
5655 	    REGCP_UNWIND(ST.cp);
5656             UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
5657 	    scan = ST.next_branch;
5658 	    /* no more branches? */
5659 	    if (!scan || (OP(scan) != BRANCH && OP(scan) != BRANCHJ)) {
5660 	        DEBUG_EXECUTE_r({
5661 		    PerlIO_printf( Perl_debug_log,
5662 			"%*s  %sBRANCH failed...%s\n",
5663 			REPORT_CODE_OFF+depth*2, "",
5664 			PL_colors[4],
5665 			PL_colors[5] );
5666 		});
5667 		sayNO_SILENT;
5668             }
5669 	    continue; /* execute next BRANCH[J] op */
5670 	    assert(0); /* NOTREACHED */
5671 
5672 	case MINMOD: /* next op will be non-greedy, e.g. A*?  */
5673 	    minmod = 1;
5674 	    break;
5675 
5676 #undef  ST
5677 #define ST st->u.curlym
5678 
5679 	case CURLYM:	/* /A{m,n}B/ where A is fixed-length */
5680 
5681 	    /* This is an optimisation of CURLYX that enables us to push
5682 	     * only a single backtracking state, no matter how many matches
5683 	     * there are in {m,n}. It relies on the pattern being constant
5684 	     * length, with no parens to influence future backrefs
5685 	     */
5686 
5687 	    ST.me = scan;
5688 	    scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
5689 
5690 	    ST.lastparen      = rex->lastparen;
5691 	    ST.lastcloseparen = rex->lastcloseparen;
5692 
5693 	    /* if paren positive, emulate an OPEN/CLOSE around A */
5694 	    if (ST.me->flags) {
5695 		U32 paren = ST.me->flags;
5696 		if (paren > maxopenparen)
5697 		    maxopenparen = paren;
5698 		scan += NEXT_OFF(scan); /* Skip former OPEN. */
5699 	    }
5700 	    ST.A = scan;
5701 	    ST.B = next;
5702 	    ST.alen = 0;
5703 	    ST.count = 0;
5704 	    ST.minmod = minmod;
5705 	    minmod = 0;
5706 	    ST.c1 = CHRTEST_UNINIT;
5707 	    REGCP_SET(ST.cp);
5708 
5709 	    if (!(ST.minmod ? ARG1(ST.me) : ARG2(ST.me))) /* min/max */
5710 		goto curlym_do_B;
5711 
5712 	  curlym_do_A: /* execute the A in /A{m,n}B/  */
5713 	    PUSH_YES_STATE_GOTO(CURLYM_A, ST.A, locinput); /* match A */
5714 	    assert(0); /* NOTREACHED */
5715 
5716 	case CURLYM_A: /* we've just matched an A */
5717 	    ST.count++;
5718 	    /* after first match, determine A's length: u.curlym.alen */
5719 	    if (ST.count == 1) {
5720 		if (PL_reg_match_utf8) {
5721 		    char *s = st->locinput;
5722 		    while (s < locinput) {
5723 			ST.alen++;
5724 			s += UTF8SKIP(s);
5725 		    }
5726 		}
5727 		else {
5728 		    ST.alen = locinput - st->locinput;
5729 		}
5730 		if (ST.alen == 0)
5731 		    ST.count = ST.minmod ? ARG1(ST.me) : ARG2(ST.me);
5732 	    }
5733 	    DEBUG_EXECUTE_r(
5734 		PerlIO_printf(Perl_debug_log,
5735 			  "%*s  CURLYM now matched %"IVdf" times, len=%"IVdf"...\n",
5736 			  (int)(REPORT_CODE_OFF+(depth*2)), "",
5737 			  (IV) ST.count, (IV)ST.alen)
5738 	    );
5739 
5740 	    if (cur_eval && cur_eval->u.eval.close_paren &&
5741 	        cur_eval->u.eval.close_paren == (U32)ST.me->flags)
5742 	        goto fake_end;
5743 
5744 	    {
5745 		I32 max = (ST.minmod ? ARG1(ST.me) : ARG2(ST.me));
5746 		if ( max == REG_INFTY || ST.count < max )
5747 		    goto curlym_do_A; /* try to match another A */
5748 	    }
5749 	    goto curlym_do_B; /* try to match B */
5750 
5751 	case CURLYM_A_fail: /* just failed to match an A */
5752 	    REGCP_UNWIND(ST.cp);
5753 
5754 	    if (ST.minmod || ST.count < ARG1(ST.me) /* min*/
5755 	        || (cur_eval && cur_eval->u.eval.close_paren &&
5756 	            cur_eval->u.eval.close_paren == (U32)ST.me->flags))
5757 		sayNO;
5758 
5759 	  curlym_do_B: /* execute the B in /A{m,n}B/  */
5760 	    if (ST.c1 == CHRTEST_UNINIT) {
5761 		/* calculate c1 and c2 for possible match of 1st char
5762 		 * following curly */
5763 		ST.c1 = ST.c2 = CHRTEST_VOID;
5764 		if (HAS_TEXT(ST.B) || JUMPABLE(ST.B)) {
5765 		    regnode *text_node = ST.B;
5766 		    if (! HAS_TEXT(text_node))
5767 			FIND_NEXT_IMPT(text_node);
5768 	            /* this used to be
5769 
5770 	                (HAS_TEXT(text_node) && PL_regkind[OP(text_node)] == EXACT)
5771 
5772 	            	But the former is redundant in light of the latter.
5773 
5774 	            	if this changes back then the macro for
5775 	            	IS_TEXT and friends need to change.
5776 	             */
5777 		    if (PL_regkind[OP(text_node)] == EXACT) {
5778                         if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
5779                            text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8,
5780                            is_utf8_pat))
5781                         {
5782                             sayNO;
5783                         }
5784 		    }
5785 		}
5786 	    }
5787 
5788 	    DEBUG_EXECUTE_r(
5789 		PerlIO_printf(Perl_debug_log,
5790 		    "%*s  CURLYM trying tail with matches=%"IVdf"...\n",
5791 		    (int)(REPORT_CODE_OFF+(depth*2)),
5792 		    "", (IV)ST.count)
5793 		);
5794 	    if (! NEXTCHR_IS_EOS && ST.c1 != CHRTEST_VOID) {
5795                 if (! UTF8_IS_INVARIANT(nextchr) && utf8_target) {
5796                     if (memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
5797                         && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
5798                     {
5799                         /* simulate B failing */
5800                         DEBUG_OPTIMISE_r(
5801                             PerlIO_printf(Perl_debug_log,
5802                                 "%*s  CURLYM Fast bail next target=U+%"UVXf" c1=U+%"UVXf" c2=U+%"UVXf"\n",
5803                                 (int)(REPORT_CODE_OFF+(depth*2)),"",
5804                                 valid_utf8_to_uvchr((U8 *) locinput, NULL),
5805                                 valid_utf8_to_uvchr(ST.c1_utf8, NULL),
5806                                 valid_utf8_to_uvchr(ST.c2_utf8, NULL))
5807                         );
5808                         state_num = CURLYM_B_fail;
5809                         goto reenter_switch;
5810                     }
5811                 }
5812                 else if (nextchr != ST.c1 && nextchr != ST.c2) {
5813                     /* simulate B failing */
5814                     DEBUG_OPTIMISE_r(
5815                         PerlIO_printf(Perl_debug_log,
5816                             "%*s  CURLYM Fast bail next target=U+%X c1=U+%X c2=U+%X\n",
5817                             (int)(REPORT_CODE_OFF+(depth*2)),"",
5818                             (int) nextchr, ST.c1, ST.c2)
5819                     );
5820                     state_num = CURLYM_B_fail;
5821                     goto reenter_switch;
5822                 }
5823             }
5824 
5825 	    if (ST.me->flags) {
5826 		/* emulate CLOSE: mark current A as captured */
5827 		I32 paren = ST.me->flags;
5828 		if (ST.count) {
5829 		    rex->offs[paren].start
5830 			= HOPc(locinput, -ST.alen) - PL_bostr;
5831 		    rex->offs[paren].end = locinput - PL_bostr;
5832 		    if ((U32)paren > rex->lastparen)
5833 			rex->lastparen = paren;
5834 		    rex->lastcloseparen = paren;
5835 		}
5836 		else
5837 		    rex->offs[paren].end = -1;
5838 		if (cur_eval && cur_eval->u.eval.close_paren &&
5839 		    cur_eval->u.eval.close_paren == (U32)ST.me->flags)
5840 		{
5841 		    if (ST.count)
5842 	                goto fake_end;
5843 	            else
5844 	                sayNO;
5845 	        }
5846 	    }
5847 
5848 	    PUSH_STATE_GOTO(CURLYM_B, ST.B, locinput); /* match B */
5849 	    assert(0); /* NOTREACHED */
5850 
5851 	case CURLYM_B_fail: /* just failed to match a B */
5852 	    REGCP_UNWIND(ST.cp);
5853             UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
5854 	    if (ST.minmod) {
5855 		I32 max = ARG2(ST.me);
5856 		if (max != REG_INFTY && ST.count == max)
5857 		    sayNO;
5858 		goto curlym_do_A; /* try to match a further A */
5859 	    }
5860 	    /* backtrack one A */
5861 	    if (ST.count == ARG1(ST.me) /* min */)
5862 		sayNO;
5863 	    ST.count--;
5864 	    SET_locinput(HOPc(locinput, -ST.alen));
5865 	    goto curlym_do_B; /* try to match B */
5866 
5867 #undef ST
5868 #define ST st->u.curly
5869 
5870 #define CURLY_SETPAREN(paren, success) \
5871     if (paren) { \
5872 	if (success) { \
5873 	    rex->offs[paren].start = HOPc(locinput, -1) - PL_bostr; \
5874 	    rex->offs[paren].end = locinput - PL_bostr; \
5875 	    if (paren > rex->lastparen) \
5876 		rex->lastparen = paren; \
5877 	    rex->lastcloseparen = paren; \
5878 	} \
5879 	else { \
5880 	    rex->offs[paren].end = -1; \
5881 	    rex->lastparen      = ST.lastparen; \
5882 	    rex->lastcloseparen = ST.lastcloseparen; \
5883 	} \
5884     }
5885 
5886         case STAR:		/*  /A*B/ where A is width 1 char */
5887 	    ST.paren = 0;
5888 	    ST.min = 0;
5889 	    ST.max = REG_INFTY;
5890 	    scan = NEXTOPER(scan);
5891 	    goto repeat;
5892 
5893         case PLUS:		/*  /A+B/ where A is width 1 char */
5894 	    ST.paren = 0;
5895 	    ST.min = 1;
5896 	    ST.max = REG_INFTY;
5897 	    scan = NEXTOPER(scan);
5898 	    goto repeat;
5899 
5900 	case CURLYN:		/*  /(A){m,n}B/ where A is width 1 char */
5901             ST.paren = scan->flags;	/* Which paren to set */
5902             ST.lastparen      = rex->lastparen;
5903 	    ST.lastcloseparen = rex->lastcloseparen;
5904 	    if (ST.paren > maxopenparen)
5905 		maxopenparen = ST.paren;
5906 	    ST.min = ARG1(scan);  /* min to match */
5907 	    ST.max = ARG2(scan);  /* max to match */
5908 	    if (cur_eval && cur_eval->u.eval.close_paren &&
5909 	        cur_eval->u.eval.close_paren == (U32)ST.paren) {
5910 	        ST.min=1;
5911 	        ST.max=1;
5912 	    }
5913             scan = regnext(NEXTOPER(scan) + NODE_STEP_REGNODE);
5914 	    goto repeat;
5915 
5916 	case CURLY:		/*  /A{m,n}B/ where A is width 1 char */
5917 	    ST.paren = 0;
5918 	    ST.min = ARG1(scan);  /* min to match */
5919 	    ST.max = ARG2(scan);  /* max to match */
5920 	    scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
5921 	  repeat:
5922 	    /*
5923 	    * Lookahead to avoid useless match attempts
5924 	    * when we know what character comes next.
5925 	    *
5926 	    * Used to only do .*x and .*?x, but now it allows
5927 	    * for )'s, ('s and (?{ ... })'s to be in the way
5928 	    * of the quantifier and the EXACT-like node.  -- japhy
5929 	    */
5930 
5931 	    assert(ST.min <= ST.max);
5932             if (! HAS_TEXT(next) && ! JUMPABLE(next)) {
5933                 ST.c1 = ST.c2 = CHRTEST_VOID;
5934             }
5935             else {
5936 		regnode *text_node = next;
5937 
5938 		if (! HAS_TEXT(text_node))
5939 		    FIND_NEXT_IMPT(text_node);
5940 
5941 		if (! HAS_TEXT(text_node))
5942 		    ST.c1 = ST.c2 = CHRTEST_VOID;
5943 		else {
5944 		    if ( PL_regkind[OP(text_node)] != EXACT ) {
5945 			ST.c1 = ST.c2 = CHRTEST_VOID;
5946 		    }
5947 		    else {
5948 
5949                     /*  Currently we only get here when
5950 
5951                         PL_rekind[OP(text_node)] == EXACT
5952 
5953                         if this changes back then the macro for IS_TEXT and
5954                         friends need to change. */
5955                         if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
5956                            text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8,
5957                            is_utf8_pat))
5958                         {
5959                             sayNO;
5960                         }
5961                     }
5962 		}
5963 	    }
5964 
5965 	    ST.A = scan;
5966 	    ST.B = next;
5967 	    if (minmod) {
5968                 char *li = locinput;
5969 		minmod = 0;
5970 		if (ST.min &&
5971                         regrepeat(rex, &li, ST.A, ST.min, depth, is_utf8_pat)
5972                             < ST.min)
5973 		    sayNO;
5974                 SET_locinput(li);
5975 		ST.count = ST.min;
5976 		REGCP_SET(ST.cp);
5977 		if (ST.c1 == CHRTEST_VOID)
5978 		    goto curly_try_B_min;
5979 
5980 		ST.oldloc = locinput;
5981 
5982 		/* set ST.maxpos to the furthest point along the
5983 		 * string that could possibly match */
5984 		if  (ST.max == REG_INFTY) {
5985 		    ST.maxpos = PL_regeol - 1;
5986 		    if (utf8_target)
5987 			while (UTF8_IS_CONTINUATION(*(U8*)ST.maxpos))
5988 			    ST.maxpos--;
5989 		}
5990 		else if (utf8_target) {
5991 		    int m = ST.max - ST.min;
5992 		    for (ST.maxpos = locinput;
5993 			 m >0 && ST.maxpos < PL_regeol; m--)
5994 			ST.maxpos += UTF8SKIP(ST.maxpos);
5995 		}
5996 		else {
5997 		    ST.maxpos = locinput + ST.max - ST.min;
5998 		    if (ST.maxpos >= PL_regeol)
5999 			ST.maxpos = PL_regeol - 1;
6000 		}
6001 		goto curly_try_B_min_known;
6002 
6003 	    }
6004 	    else {
6005                 /* avoid taking address of locinput, so it can remain
6006                  * a register var */
6007                 char *li = locinput;
6008 		ST.count = regrepeat(rex, &li, ST.A, ST.max, depth,
6009                                         is_utf8_pat);
6010 		if (ST.count < ST.min)
6011 		    sayNO;
6012                 SET_locinput(li);
6013 		if ((ST.count > ST.min)
6014 		    && (PL_regkind[OP(ST.B)] == EOL) && (OP(ST.B) != MEOL))
6015 		{
6016 		    /* A{m,n} must come at the end of the string, there's
6017 		     * no point in backing off ... */
6018 		    ST.min = ST.count;
6019 		    /* ...except that $ and \Z can match before *and* after
6020 		       newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
6021 		       We may back off by one in this case. */
6022 		    if (UCHARAT(locinput - 1) == '\n' && OP(ST.B) != EOS)
6023 			ST.min--;
6024 		}
6025 		REGCP_SET(ST.cp);
6026 		goto curly_try_B_max;
6027 	    }
6028 	    assert(0); /* NOTREACHED */
6029 
6030 
6031 	case CURLY_B_min_known_fail:
6032 	    /* failed to find B in a non-greedy match where c1,c2 valid */
6033 
6034 	    REGCP_UNWIND(ST.cp);
6035             if (ST.paren) {
6036                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
6037             }
6038 	    /* Couldn't or didn't -- move forward. */
6039 	    ST.oldloc = locinput;
6040 	    if (utf8_target)
6041 		locinput += UTF8SKIP(locinput);
6042 	    else
6043 		locinput++;
6044 	    ST.count++;
6045 	  curly_try_B_min_known:
6046 	     /* find the next place where 'B' could work, then call B */
6047 	    {
6048 		int n;
6049 		if (utf8_target) {
6050 		    n = (ST.oldloc == locinput) ? 0 : 1;
6051 		    if (ST.c1 == ST.c2) {
6052 			/* set n to utf8_distance(oldloc, locinput) */
6053 			while (locinput <= ST.maxpos
6054                               && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput)))
6055                         {
6056 			    locinput += UTF8SKIP(locinput);
6057 			    n++;
6058 			}
6059 		    }
6060 		    else {
6061 			/* set n to utf8_distance(oldloc, locinput) */
6062 			while (locinput <= ST.maxpos
6063                               && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
6064                               && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
6065                         {
6066 			    locinput += UTF8SKIP(locinput);
6067 			    n++;
6068 			}
6069 		    }
6070 		}
6071 		else {  /* Not utf8_target */
6072 		    if (ST.c1 == ST.c2) {
6073 			while (locinput <= ST.maxpos &&
6074 			       UCHARAT(locinput) != ST.c1)
6075 			    locinput++;
6076 		    }
6077 		    else {
6078 			while (locinput <= ST.maxpos
6079 			       && UCHARAT(locinput) != ST.c1
6080 			       && UCHARAT(locinput) != ST.c2)
6081 			    locinput++;
6082 		    }
6083 		    n = locinput - ST.oldloc;
6084 		}
6085 		if (locinput > ST.maxpos)
6086 		    sayNO;
6087 		if (n) {
6088                     /* In /a{m,n}b/, ST.oldloc is at "a" x m, locinput is
6089                      * at b; check that everything between oldloc and
6090                      * locinput matches */
6091                     char *li = ST.oldloc;
6092 		    ST.count += n;
6093 		    if (regrepeat(rex, &li, ST.A, n, depth, is_utf8_pat) < n)
6094 			sayNO;
6095                     assert(n == REG_INFTY || locinput == li);
6096 		}
6097 		CURLY_SETPAREN(ST.paren, ST.count);
6098 		if (cur_eval && cur_eval->u.eval.close_paren &&
6099 		    cur_eval->u.eval.close_paren == (U32)ST.paren) {
6100 		    goto fake_end;
6101 	        }
6102 		PUSH_STATE_GOTO(CURLY_B_min_known, ST.B, locinput);
6103 	    }
6104 	    assert(0); /* NOTREACHED */
6105 
6106 
6107 	case CURLY_B_min_fail:
6108 	    /* failed to find B in a non-greedy match where c1,c2 invalid */
6109 
6110 	    REGCP_UNWIND(ST.cp);
6111             if (ST.paren) {
6112                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
6113             }
6114 	    /* failed -- move forward one */
6115             {
6116                 char *li = locinput;
6117                 if (!regrepeat(rex, &li, ST.A, 1, depth, is_utf8_pat)) {
6118                     sayNO;
6119                 }
6120                 locinput = li;
6121             }
6122             {
6123 		ST.count++;
6124 		if (ST.count <= ST.max || (ST.max == REG_INFTY &&
6125 			ST.count > 0)) /* count overflow ? */
6126 		{
6127 		  curly_try_B_min:
6128 		    CURLY_SETPAREN(ST.paren, ST.count);
6129 		    if (cur_eval && cur_eval->u.eval.close_paren &&
6130 		        cur_eval->u.eval.close_paren == (U32)ST.paren) {
6131                         goto fake_end;
6132                     }
6133 		    PUSH_STATE_GOTO(CURLY_B_min, ST.B, locinput);
6134 		}
6135 	    }
6136             sayNO;
6137 	    assert(0); /* NOTREACHED */
6138 
6139 
6140 	curly_try_B_max:
6141 	    /* a successful greedy match: now try to match B */
6142             if (cur_eval && cur_eval->u.eval.close_paren &&
6143                 cur_eval->u.eval.close_paren == (U32)ST.paren) {
6144                 goto fake_end;
6145             }
6146 	    {
6147 		bool could_match = locinput < PL_regeol;
6148 
6149 		/* If it could work, try it. */
6150                 if (ST.c1 != CHRTEST_VOID && could_match) {
6151                     if (! UTF8_IS_INVARIANT(UCHARAT(locinput)) && utf8_target)
6152                     {
6153                         could_match = memEQ(locinput,
6154                                             ST.c1_utf8,
6155                                             UTF8SKIP(locinput))
6156                                     || memEQ(locinput,
6157                                              ST.c2_utf8,
6158                                              UTF8SKIP(locinput));
6159                     }
6160                     else {
6161                         could_match = UCHARAT(locinput) == ST.c1
6162                                       || UCHARAT(locinput) == ST.c2;
6163                     }
6164                 }
6165                 if (ST.c1 == CHRTEST_VOID || could_match) {
6166 		    CURLY_SETPAREN(ST.paren, ST.count);
6167 		    PUSH_STATE_GOTO(CURLY_B_max, ST.B, locinput);
6168 		    assert(0); /* NOTREACHED */
6169 		}
6170 	    }
6171 	    /* FALL THROUGH */
6172 
6173 	case CURLY_B_max_fail:
6174 	    /* failed to find B in a greedy match */
6175 
6176 	    REGCP_UNWIND(ST.cp);
6177             if (ST.paren) {
6178                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
6179             }
6180 	    /*  back up. */
6181 	    if (--ST.count < ST.min)
6182 		sayNO;
6183 	    locinput = HOPc(locinput, -1);
6184 	    goto curly_try_B_max;
6185 
6186 #undef ST
6187 
6188 	case END: /*  last op of main pattern  */
6189 	    fake_end:
6190 	    if (cur_eval) {
6191 		/* we've just finished A in /(??{A})B/; now continue with B */
6192                 st->u.eval.saved_utf8_pat = is_utf8_pat;
6193 		is_utf8_pat = cur_eval->u.eval.saved_utf8_pat;
6194 
6195 		st->u.eval.prev_rex = rex_sv;		/* inner */
6196 
6197                 /* Save *all* the positions. */
6198 		st->u.eval.cp = regcppush(rex, 0, maxopenparen);
6199 		rex_sv = cur_eval->u.eval.prev_rex;
6200 		SET_reg_curpm(rex_sv);
6201 		rex = ReANY(rex_sv);
6202 		rexi = RXi_GET(rex);
6203 		cur_curlyx = cur_eval->u.eval.prev_curlyx;
6204 
6205 		REGCP_SET(st->u.eval.lastcp);
6206 
6207 		/* Restore parens of the outer rex without popping the
6208 		 * savestack */
6209 		S_regcp_restore(aTHX_ rex, cur_eval->u.eval.lastcp,
6210                                         &maxopenparen);
6211 
6212 		st->u.eval.prev_eval = cur_eval;
6213 		cur_eval = cur_eval->u.eval.prev_eval;
6214 		DEBUG_EXECUTE_r(
6215 		    PerlIO_printf(Perl_debug_log, "%*s  EVAL trying tail ... %"UVxf"\n",
6216 				      REPORT_CODE_OFF+depth*2, "",PTR2UV(cur_eval)););
6217                 if ( nochange_depth )
6218 	            nochange_depth--;
6219 
6220                 PUSH_YES_STATE_GOTO(EVAL_AB, st->u.eval.prev_eval->u.eval.B,
6221                                     locinput); /* match B */
6222 	    }
6223 
6224 	    if (locinput < reginfo->till) {
6225 		DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
6226 				      "%sMatch possible, but length=%ld is smaller than requested=%ld, failing!%s\n",
6227 				      PL_colors[4],
6228 				      (long)(locinput - PL_reg_starttry),
6229 				      (long)(reginfo->till - PL_reg_starttry),
6230 				      PL_colors[5]));
6231 
6232 		sayNO_SILENT;		/* Cannot match: too short. */
6233 	    }
6234 	    sayYES;			/* Success! */
6235 
6236 	case SUCCEED: /* successful SUSPEND/UNLESSM/IFMATCH/CURLYM */
6237 	    DEBUG_EXECUTE_r(
6238 	    PerlIO_printf(Perl_debug_log,
6239 		"%*s  %ssubpattern success...%s\n",
6240 		REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5]));
6241 	    sayYES;			/* Success! */
6242 
6243 #undef  ST
6244 #define ST st->u.ifmatch
6245 
6246         {
6247             char *newstart;
6248 
6249 	case SUSPEND:	/* (?>A) */
6250 	    ST.wanted = 1;
6251 	    newstart = locinput;
6252 	    goto do_ifmatch;
6253 
6254 	case UNLESSM:	/* -ve lookaround: (?!A), or with flags, (?<!A) */
6255 	    ST.wanted = 0;
6256 	    goto ifmatch_trivial_fail_test;
6257 
6258 	case IFMATCH:	/* +ve lookaround: (?=A), or with flags, (?<=A) */
6259 	    ST.wanted = 1;
6260 	  ifmatch_trivial_fail_test:
6261 	    if (scan->flags) {
6262 		char * const s = HOPBACKc(locinput, scan->flags);
6263 		if (!s) {
6264 		    /* trivial fail */
6265 		    if (logical) {
6266 			logical = 0;
6267 			sw = 1 - cBOOL(ST.wanted);
6268 		    }
6269 		    else if (ST.wanted)
6270 			sayNO;
6271 		    next = scan + ARG(scan);
6272 		    if (next == scan)
6273 			next = NULL;
6274 		    break;
6275 		}
6276 		newstart = s;
6277 	    }
6278 	    else
6279 		newstart = locinput;
6280 
6281 	  do_ifmatch:
6282 	    ST.me = scan;
6283 	    ST.logical = logical;
6284 	    logical = 0; /* XXX: reset state of logical once it has been saved into ST */
6285 
6286 	    /* execute body of (?...A) */
6287 	    PUSH_YES_STATE_GOTO(IFMATCH_A, NEXTOPER(NEXTOPER(scan)), newstart);
6288 	    assert(0); /* NOTREACHED */
6289         }
6290 
6291 	case IFMATCH_A_fail: /* body of (?...A) failed */
6292 	    ST.wanted = !ST.wanted;
6293 	    /* FALL THROUGH */
6294 
6295 	case IFMATCH_A: /* body of (?...A) succeeded */
6296 	    if (ST.logical) {
6297 		sw = cBOOL(ST.wanted);
6298 	    }
6299 	    else if (!ST.wanted)
6300 		sayNO;
6301 
6302 	    if (OP(ST.me) != SUSPEND) {
6303                 /* restore old position except for (?>...) */
6304 		locinput = st->locinput;
6305 	    }
6306 	    scan = ST.me + ARG(ST.me);
6307 	    if (scan == ST.me)
6308 		scan = NULL;
6309 	    continue; /* execute B */
6310 
6311 #undef ST
6312 
6313 	case LONGJMP: /*  alternative with many branches compiles to
6314                        * (BRANCHJ; EXACT ...; LONGJMP ) x N */
6315 	    next = scan + ARG(scan);
6316 	    if (next == scan)
6317 		next = NULL;
6318 	    break;
6319 
6320 	case COMMIT:  /*  (*COMMIT)  */
6321 	    reginfo->cutpoint = PL_regeol;
6322 	    /* FALLTHROUGH */
6323 
6324 	case PRUNE:   /*  (*PRUNE)   */
6325 	    if (!scan->flags)
6326 	        sv_yes_mark = sv_commit = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
6327 	    PUSH_STATE_GOTO(COMMIT_next, next, locinput);
6328 	    assert(0); /* NOTREACHED */
6329 
6330 	case COMMIT_next_fail:
6331 	    no_final = 1;
6332 	    /* FALLTHROUGH */
6333 
6334 	case OPFAIL:   /* (*FAIL)  */
6335 	    sayNO;
6336 	    assert(0); /* NOTREACHED */
6337 
6338 #define ST st->u.mark
6339         case MARKPOINT: /*  (*MARK:foo)  */
6340             ST.prev_mark = mark_state;
6341             ST.mark_name = sv_commit = sv_yes_mark
6342                 = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
6343             mark_state = st;
6344             ST.mark_loc = locinput;
6345             PUSH_YES_STATE_GOTO(MARKPOINT_next, next, locinput);
6346             assert(0); /* NOTREACHED */
6347 
6348         case MARKPOINT_next:
6349             mark_state = ST.prev_mark;
6350             sayYES;
6351             assert(0); /* NOTREACHED */
6352 
6353         case MARKPOINT_next_fail:
6354             if (popmark && sv_eq(ST.mark_name,popmark))
6355             {
6356                 if (ST.mark_loc > startpoint)
6357 	            reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
6358                 popmark = NULL; /* we found our mark */
6359                 sv_commit = ST.mark_name;
6360 
6361                 DEBUG_EXECUTE_r({
6362                         PerlIO_printf(Perl_debug_log,
6363 		            "%*s  %ssetting cutpoint to mark:%"SVf"...%s\n",
6364 		            REPORT_CODE_OFF+depth*2, "",
6365 		            PL_colors[4], SVfARG(sv_commit), PL_colors[5]);
6366 		});
6367             }
6368             mark_state = ST.prev_mark;
6369             sv_yes_mark = mark_state ?
6370                 mark_state->u.mark.mark_name : NULL;
6371             sayNO;
6372             assert(0); /* NOTREACHED */
6373 
6374         case SKIP:  /*  (*SKIP)  */
6375             if (scan->flags) {
6376                 /* (*SKIP) : if we fail we cut here*/
6377                 ST.mark_name = NULL;
6378                 ST.mark_loc = locinput;
6379                 PUSH_STATE_GOTO(SKIP_next,next, locinput);
6380             } else {
6381                 /* (*SKIP:NAME) : if there is a (*MARK:NAME) fail where it was,
6382                    otherwise do nothing.  Meaning we need to scan
6383                  */
6384                 regmatch_state *cur = mark_state;
6385                 SV *find = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
6386 
6387                 while (cur) {
6388                     if ( sv_eq( cur->u.mark.mark_name,
6389                                 find ) )
6390                     {
6391                         ST.mark_name = find;
6392                         PUSH_STATE_GOTO( SKIP_next, next, locinput);
6393                     }
6394                     cur = cur->u.mark.prev_mark;
6395                 }
6396             }
6397             /* Didn't find our (*MARK:NAME) so ignore this (*SKIP:NAME) */
6398             break;
6399 
6400 	case SKIP_next_fail:
6401 	    if (ST.mark_name) {
6402 	        /* (*CUT:NAME) - Set up to search for the name as we
6403 	           collapse the stack*/
6404 	        popmark = ST.mark_name;
6405 	    } else {
6406 	        /* (*CUT) - No name, we cut here.*/
6407 	        if (ST.mark_loc > startpoint)
6408 	            reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
6409 	        /* but we set sv_commit to latest mark_name if there
6410 	           is one so they can test to see how things lead to this
6411 	           cut */
6412                 if (mark_state)
6413                     sv_commit=mark_state->u.mark.mark_name;
6414             }
6415             no_final = 1;
6416             sayNO;
6417             assert(0); /* NOTREACHED */
6418 #undef ST
6419 
6420         case LNBREAK: /* \R */
6421             if ((n=is_LNBREAK_safe(locinput, PL_regeol, utf8_target))) {
6422                 locinput += n;
6423             } else
6424                 sayNO;
6425             break;
6426 
6427 	default:
6428 	    PerlIO_printf(Perl_error_log, "%"UVxf" %d\n",
6429 			  PTR2UV(scan), OP(scan));
6430 	    Perl_croak(aTHX_ "regexp memory corruption");
6431 
6432         /* this is a point to jump to in order to increment
6433          * locinput by one character */
6434         increment_locinput:
6435             assert(!NEXTCHR_IS_EOS);
6436             if (utf8_target) {
6437                 locinput += PL_utf8skip[nextchr];
6438                 /* locinput is allowed to go 1 char off the end, but not 2+ */
6439                 if (locinput > PL_regeol)
6440                     sayNO;
6441             }
6442             else
6443                 locinput++;
6444             break;
6445 
6446 	} /* end switch */
6447 
6448         /* switch break jumps here */
6449 	scan = next; /* prepare to execute the next op and ... */
6450 	continue;    /* ... jump back to the top, reusing st */
6451 	assert(0); /* NOTREACHED */
6452 
6453       push_yes_state:
6454 	/* push a state that backtracks on success */
6455 	st->u.yes.prev_yes_state = yes_state;
6456 	yes_state = st;
6457 	/* FALL THROUGH */
6458       push_state:
6459 	/* push a new regex state, then continue at scan  */
6460 	{
6461 	    regmatch_state *newst;
6462 
6463 	    DEBUG_STACK_r({
6464 	        regmatch_state *cur = st;
6465 	        regmatch_state *curyes = yes_state;
6466 	        int curd = depth;
6467 	        regmatch_slab *slab = PL_regmatch_slab;
6468                 for (;curd > -1;cur--,curd--) {
6469                     if (cur < SLAB_FIRST(slab)) {
6470                 	slab = slab->prev;
6471                 	cur = SLAB_LAST(slab);
6472                     }
6473                     PerlIO_printf(Perl_error_log, "%*s#%-3d %-10s %s\n",
6474                         REPORT_CODE_OFF + 2 + depth * 2,"",
6475                         curd, PL_reg_name[cur->resume_state],
6476                         (curyes == cur) ? "yes" : ""
6477                     );
6478                     if (curyes == cur)
6479 	                curyes = cur->u.yes.prev_yes_state;
6480                 }
6481             } else
6482                 DEBUG_STATE_pp("push")
6483             );
6484 	    depth++;
6485 	    st->locinput = locinput;
6486 	    newst = st+1;
6487 	    if (newst >  SLAB_LAST(PL_regmatch_slab))
6488 		newst = S_push_slab(aTHX);
6489 	    PL_regmatch_state = newst;
6490 
6491 	    locinput = pushinput;
6492 	    st = newst;
6493 	    continue;
6494 	    assert(0); /* NOTREACHED */
6495 	}
6496     }
6497 
6498     /*
6499     * We get here only if there's trouble -- normally "case END" is
6500     * the terminating point.
6501     */
6502     Perl_croak(aTHX_ "corrupted regexp pointers");
6503     /*NOTREACHED*/
6504     sayNO;
6505 
6506 yes:
6507     if (yes_state) {
6508 	/* we have successfully completed a subexpression, but we must now
6509 	 * pop to the state marked by yes_state and continue from there */
6510 	assert(st != yes_state);
6511 #ifdef DEBUGGING
6512 	while (st != yes_state) {
6513 	    st--;
6514 	    if (st < SLAB_FIRST(PL_regmatch_slab)) {
6515 		PL_regmatch_slab = PL_regmatch_slab->prev;
6516 		st = SLAB_LAST(PL_regmatch_slab);
6517 	    }
6518 	    DEBUG_STATE_r({
6519 	        if (no_final) {
6520 	            DEBUG_STATE_pp("pop (no final)");
6521 	        } else {
6522 	            DEBUG_STATE_pp("pop (yes)");
6523 	        }
6524 	    });
6525 	    depth--;
6526 	}
6527 #else
6528 	while (yes_state < SLAB_FIRST(PL_regmatch_slab)
6529 	    || yes_state > SLAB_LAST(PL_regmatch_slab))
6530 	{
6531 	    /* not in this slab, pop slab */
6532 	    depth -= (st - SLAB_FIRST(PL_regmatch_slab) + 1);
6533 	    PL_regmatch_slab = PL_regmatch_slab->prev;
6534 	    st = SLAB_LAST(PL_regmatch_slab);
6535 	}
6536 	depth -= (st - yes_state);
6537 #endif
6538 	st = yes_state;
6539 	yes_state = st->u.yes.prev_yes_state;
6540 	PL_regmatch_state = st;
6541 
6542         if (no_final)
6543             locinput= st->locinput;
6544 	state_num = st->resume_state + no_final;
6545 	goto reenter_switch;
6546     }
6547 
6548     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
6549 			  PL_colors[4], PL_colors[5]));
6550 
6551     if (PL_reg_state.re_state_eval_setup_done) {
6552 	/* each successfully executed (?{...}) block does the equivalent of
6553 	 *   local $^R = do {...}
6554 	 * When popping the save stack, all these locals would be undone;
6555 	 * bypass this by setting the outermost saved $^R to the latest
6556 	 * value */
6557 	if (oreplsv != GvSV(PL_replgv))
6558 	    sv_setsv(oreplsv, GvSV(PL_replgv));
6559     }
6560     result = 1;
6561     goto final_exit;
6562 
6563 no:
6564     DEBUG_EXECUTE_r(
6565 	PerlIO_printf(Perl_debug_log,
6566             "%*s  %sfailed...%s\n",
6567             REPORT_CODE_OFF+depth*2, "",
6568             PL_colors[4], PL_colors[5])
6569 	);
6570 
6571 no_silent:
6572     if (no_final) {
6573         if (yes_state) {
6574             goto yes;
6575         } else {
6576             goto final_exit;
6577         }
6578     }
6579     if (depth) {
6580 	/* there's a previous state to backtrack to */
6581 	st--;
6582 	if (st < SLAB_FIRST(PL_regmatch_slab)) {
6583 	    PL_regmatch_slab = PL_regmatch_slab->prev;
6584 	    st = SLAB_LAST(PL_regmatch_slab);
6585 	}
6586 	PL_regmatch_state = st;
6587 	locinput= st->locinput;
6588 
6589 	DEBUG_STATE_pp("pop");
6590 	depth--;
6591 	if (yes_state == st)
6592 	    yes_state = st->u.yes.prev_yes_state;
6593 
6594 	state_num = st->resume_state + 1; /* failure = success + 1 */
6595 	goto reenter_switch;
6596     }
6597     result = 0;
6598 
6599   final_exit:
6600     if (rex->intflags & PREGf_VERBARG_SEEN) {
6601         SV *sv_err = get_sv("REGERROR", 1);
6602         SV *sv_mrk = get_sv("REGMARK", 1);
6603         if (result) {
6604             sv_commit = &PL_sv_no;
6605             if (!sv_yes_mark)
6606                 sv_yes_mark = &PL_sv_yes;
6607         } else {
6608             if (!sv_commit)
6609                 sv_commit = &PL_sv_yes;
6610             sv_yes_mark = &PL_sv_no;
6611         }
6612         sv_setsv(sv_err, sv_commit);
6613         sv_setsv(sv_mrk, sv_yes_mark);
6614     }
6615 
6616 
6617     if (last_pushed_cv) {
6618 	dSP;
6619 	POP_MULTICALL;
6620         PERL_UNUSED_VAR(SP);
6621     }
6622 
6623     /* clean up; in particular, free all slabs above current one */
6624     LEAVE_SCOPE(oldsave);
6625 
6626     assert(!result ||  locinput - PL_bostr >= 0);
6627     return result ?  locinput - PL_bostr : -1;
6628 }
6629 
6630 /*
6631  - regrepeat - repeatedly match something simple, report how many
6632  *
6633  * What 'simple' means is a node which can be the operand of a quantifier like
6634  * '+', or {1,3}
6635  *
6636  * startposp - pointer a pointer to the start position.  This is updated
6637  *             to point to the byte following the highest successful
6638  *             match.
6639  * p         - the regnode to be repeatedly matched against.
6640  * max       - maximum number of things to match.
6641  * depth     - (for debugging) backtracking depth.
6642  */
6643 STATIC I32
6644 S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
6645                 I32 max, int depth, bool is_utf8_pat)
6646 {
6647     dVAR;
6648     char *scan;     /* Pointer to current position in target string */
6649     I32 c;
6650     char *loceol = PL_regeol;   /* local version */
6651     I32 hardcount = 0;  /* How many matches so far */
6652     bool utf8_target = PL_reg_match_utf8;
6653     int to_complement = 0;  /* Invert the result? */
6654     UV utf8_flags;
6655     _char_class_number classnum;
6656 #ifndef DEBUGGING
6657     PERL_UNUSED_ARG(depth);
6658 #endif
6659 
6660     PERL_ARGS_ASSERT_REGREPEAT;
6661 
6662     scan = *startposp;
6663     if (max == REG_INFTY)
6664 	max = I32_MAX;
6665     else if (! utf8_target && loceol - scan > max)
6666 	loceol = scan + max;
6667 
6668     /* Here, for the case of a non-UTF-8 target we have adjusted <loceol> down
6669      * to the maximum of how far we should go in it (leaving it set to the real
6670      * end, if the maximum permissible would take us beyond that).  This allows
6671      * us to make the loop exit condition that we haven't gone past <loceol> to
6672      * also mean that we haven't exceeded the max permissible count, saving a
6673      * test each time through the loop.  But it assumes that the OP matches a
6674      * single byte, which is true for most of the OPs below when applied to a
6675      * non-UTF-8 target.  Those relatively few OPs that don't have this
6676      * characteristic will have to compensate.
6677      *
6678      * There is no adjustment for UTF-8 targets, as the number of bytes per
6679      * character varies.  OPs will have to test both that the count is less
6680      * than the max permissible (using <hardcount> to keep track), and that we
6681      * are still within the bounds of the string (using <loceol>.  A few OPs
6682      * match a single byte no matter what the encoding.  They can omit the max
6683      * test if, for the UTF-8 case, they do the adjustment that was skipped
6684      * above.
6685      *
6686      * Thus, the code above sets things up for the common case; and exceptional
6687      * cases need extra work; the common case is to make sure <scan> doesn't
6688      * go past <loceol>, and for UTF-8 to also use <hardcount> to make sure the
6689      * count doesn't exceed the maximum permissible */
6690 
6691     switch (OP(p)) {
6692     case REG_ANY:
6693 	if (utf8_target) {
6694 	    while (scan < loceol && hardcount < max && *scan != '\n') {
6695 		scan += UTF8SKIP(scan);
6696 		hardcount++;
6697 	    }
6698 	} else {
6699 	    while (scan < loceol && *scan != '\n')
6700 		scan++;
6701 	}
6702 	break;
6703     case SANY:
6704         if (utf8_target) {
6705 	    while (scan < loceol && hardcount < max) {
6706 	        scan += UTF8SKIP(scan);
6707 		hardcount++;
6708 	    }
6709 	}
6710 	else
6711 	    scan = loceol;
6712 	break;
6713     case CANY:  /* Move <scan> forward <max> bytes, unless goes off end */
6714         if (utf8_target && loceol - scan > max) {
6715 
6716             /* <loceol> hadn't been adjusted in the UTF-8 case */
6717             scan +=  max;
6718         }
6719         else {
6720             scan = loceol;
6721         }
6722 	break;
6723     case EXACT:
6724         assert(STR_LEN(p) == is_utf8_pat ? UTF8SKIP(STRING(p)) : 1);
6725 
6726 	c = (U8)*STRING(p);
6727 
6728         /* Can use a simple loop if the pattern char to match on is invariant
6729          * under UTF-8, or both target and pattern aren't UTF-8.  Note that we
6730          * can use UTF8_IS_INVARIANT() even if the pattern isn't UTF-8, as it's
6731          * true iff it doesn't matter if the argument is in UTF-8 or not */
6732         if (UTF8_IS_INVARIANT(c) || (! utf8_target && ! is_utf8_pat)) {
6733             if (utf8_target && loceol - scan > max) {
6734                 /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
6735                  * since here, to match at all, 1 char == 1 byte */
6736                 loceol = scan + max;
6737             }
6738 	    while (scan < loceol && UCHARAT(scan) == c) {
6739 		scan++;
6740 	    }
6741 	}
6742 	else if (is_utf8_pat) {
6743             if (utf8_target) {
6744                 STRLEN scan_char_len;
6745 
6746                 /* When both target and pattern are UTF-8, we have to do
6747                  * string EQ */
6748                 while (hardcount < max
6749                        && scan < loceol
6750                        && (scan_char_len = UTF8SKIP(scan)) <= STR_LEN(p)
6751                        && memEQ(scan, STRING(p), scan_char_len))
6752                 {
6753                     scan += scan_char_len;
6754                     hardcount++;
6755                 }
6756             }
6757             else if (! UTF8_IS_ABOVE_LATIN1(c)) {
6758 
6759                 /* Target isn't utf8; convert the character in the UTF-8
6760                  * pattern to non-UTF8, and do a simple loop */
6761                 c = TWO_BYTE_UTF8_TO_UNI(c, *(STRING(p) + 1));
6762                 while (scan < loceol && UCHARAT(scan) == c) {
6763                     scan++;
6764                 }
6765             } /* else pattern char is above Latin1, can't possibly match the
6766                  non-UTF-8 target */
6767         }
6768         else {
6769 
6770             /* Here, the string must be utf8; pattern isn't, and <c> is
6771              * different in utf8 than not, so can't compare them directly.
6772              * Outside the loop, find the two utf8 bytes that represent c, and
6773              * then look for those in sequence in the utf8 string */
6774 	    U8 high = UTF8_TWO_BYTE_HI(c);
6775 	    U8 low = UTF8_TWO_BYTE_LO(c);
6776 
6777 	    while (hardcount < max
6778 		    && scan + 1 < loceol
6779 		    && UCHARAT(scan) == high
6780 		    && UCHARAT(scan + 1) == low)
6781 	    {
6782 		scan += 2;
6783 		hardcount++;
6784 	    }
6785 	}
6786 	break;
6787 
6788     case EXACTFA:
6789 	utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
6790 	goto do_exactf;
6791 
6792     case EXACTFL:
6793         RXp_MATCH_TAINTED_on(prog);
6794 	utf8_flags = FOLDEQ_UTF8_LOCALE;
6795 	goto do_exactf;
6796 
6797     case EXACTF:
6798 	    utf8_flags = 0;
6799 	    goto do_exactf;
6800 
6801     case EXACTFU_SS:
6802     case EXACTFU_TRICKYFOLD:
6803     case EXACTFU:
6804 	utf8_flags = is_utf8_pat ? FOLDEQ_S2_ALREADY_FOLDED : 0;
6805 
6806     do_exactf: {
6807         int c1, c2;
6808         U8 c1_utf8[UTF8_MAXBYTES+1], c2_utf8[UTF8_MAXBYTES+1];
6809 
6810         assert(STR_LEN(p) == is_utf8_pat ? UTF8SKIP(STRING(p)) : 1);
6811 
6812         if (S_setup_EXACTISH_ST_c1_c2(aTHX_ p, &c1, c1_utf8, &c2, c2_utf8,
6813                                         is_utf8_pat))
6814         {
6815             if (c1 == CHRTEST_VOID) {
6816                 /* Use full Unicode fold matching */
6817                 char *tmpeol = PL_regeol;
6818                 STRLEN pat_len = is_utf8_pat ? UTF8SKIP(STRING(p)) : 1;
6819                 while (hardcount < max
6820                         && foldEQ_utf8_flags(scan, &tmpeol, 0, utf8_target,
6821                                              STRING(p), NULL, pat_len,
6822                                              is_utf8_pat, utf8_flags))
6823                 {
6824                     scan = tmpeol;
6825                     tmpeol = PL_regeol;
6826                     hardcount++;
6827                 }
6828             }
6829             else if (utf8_target) {
6830                 if (c1 == c2) {
6831                     while (scan < loceol
6832                            && hardcount < max
6833                            && memEQ(scan, c1_utf8, UTF8SKIP(scan)))
6834                     {
6835                         scan += UTF8SKIP(scan);
6836                         hardcount++;
6837                     }
6838                 }
6839                 else {
6840                     while (scan < loceol
6841                            && hardcount < max
6842                            && (memEQ(scan, c1_utf8, UTF8SKIP(scan))
6843                                || memEQ(scan, c2_utf8, UTF8SKIP(scan))))
6844                     {
6845                         scan += UTF8SKIP(scan);
6846                         hardcount++;
6847                     }
6848                 }
6849             }
6850             else if (c1 == c2) {
6851                 while (scan < loceol && UCHARAT(scan) == c1) {
6852                     scan++;
6853                 }
6854             }
6855             else {
6856                 while (scan < loceol &&
6857                     (UCHARAT(scan) == c1 || UCHARAT(scan) == c2))
6858                 {
6859                     scan++;
6860                 }
6861             }
6862 	}
6863 	break;
6864     }
6865     case ANYOF:
6866     case ANYOF_WARN_SUPER:
6867 	if (utf8_target) {
6868 	    while (hardcount < max
6869                    && scan < loceol
6870 		   && reginclass(prog, p, (U8*)scan, utf8_target))
6871 	    {
6872 		scan += UTF8SKIP(scan);
6873 		hardcount++;
6874 	    }
6875 	} else {
6876 	    while (scan < loceol && REGINCLASS(prog, p, (U8*)scan))
6877 		scan++;
6878 	}
6879 	break;
6880 
6881     /* The argument (FLAGS) to all the POSIX node types is the class number */
6882 
6883     case NPOSIXL:
6884         to_complement = 1;
6885         /* FALLTHROUGH */
6886 
6887     case POSIXL:
6888         RXp_MATCH_TAINTED_on(prog);
6889 	if (! utf8_target) {
6890 	    while (scan < loceol && to_complement ^ cBOOL(isFOO_lc(FLAGS(p),
6891                                                                    *scan)))
6892             {
6893 		scan++;
6894             }
6895 	} else {
6896 	    while (hardcount < max && scan < loceol
6897                    && to_complement ^ cBOOL(isFOO_utf8_lc(FLAGS(p),
6898                                                                   (U8 *) scan)))
6899             {
6900                 scan += UTF8SKIP(scan);
6901 		hardcount++;
6902 	    }
6903 	}
6904 	break;
6905 
6906     case POSIXD:
6907         if (utf8_target) {
6908             goto utf8_posix;
6909         }
6910         /* FALLTHROUGH */
6911 
6912     case POSIXA:
6913         if (utf8_target && loceol - scan > max) {
6914 
6915             /* We didn't adjust <loceol> at the beginning of this routine
6916              * because is UTF-8, but it is actually ok to do so, since here, to
6917              * match, 1 char == 1 byte. */
6918             loceol = scan + max;
6919         }
6920         while (scan < loceol && _generic_isCC_A((U8) *scan, FLAGS(p))) {
6921 	    scan++;
6922 	}
6923 	break;
6924 
6925     case NPOSIXD:
6926         if (utf8_target) {
6927             to_complement = 1;
6928             goto utf8_posix;
6929         }
6930         /* FALL THROUGH */
6931 
6932     case NPOSIXA:
6933         if (! utf8_target) {
6934             while (scan < loceol && ! _generic_isCC_A((U8) *scan, FLAGS(p))) {
6935                 scan++;
6936             }
6937         }
6938         else {
6939 
6940             /* The complement of something that matches only ASCII matches all
6941              * UTF-8 variant code points, plus everything in ASCII that isn't
6942              * in the class. */
6943 	    while (hardcount < max && scan < loceol
6944                    && (! UTF8_IS_INVARIANT(*scan)
6945                        || ! _generic_isCC_A((U8) *scan, FLAGS(p))))
6946             {
6947                 scan += UTF8SKIP(scan);
6948 		hardcount++;
6949 	    }
6950         }
6951         break;
6952 
6953     case NPOSIXU:
6954         to_complement = 1;
6955         /* FALLTHROUGH */
6956 
6957     case POSIXU:
6958 	if (! utf8_target) {
6959             while (scan < loceol && to_complement
6960                                 ^ cBOOL(_generic_isCC((U8) *scan, FLAGS(p))))
6961             {
6962                 scan++;
6963             }
6964 	}
6965 	else {
6966       utf8_posix:
6967             classnum = (_char_class_number) FLAGS(p);
6968             if (classnum < _FIRST_NON_SWASH_CC) {
6969 
6970                 /* Here, a swash is needed for above-Latin1 code points.
6971                  * Process as many Latin1 code points using the built-in rules.
6972                  * Go to another loop to finish processing upon encountering
6973                  * the first Latin1 code point.  We could do that in this loop
6974                  * as well, but the other way saves having to test if the swash
6975                  * has been loaded every time through the loop: extra space to
6976                  * save a test. */
6977                 while (hardcount < max && scan < loceol) {
6978                     if (UTF8_IS_INVARIANT(*scan)) {
6979                         if (! (to_complement ^ cBOOL(_generic_isCC((U8) *scan,
6980                                                                    classnum))))
6981                         {
6982                             break;
6983                         }
6984                         scan++;
6985                     }
6986                     else if (UTF8_IS_DOWNGRADEABLE_START(*scan)) {
6987                         if (! (to_complement
6988                               ^ cBOOL(_generic_isCC(TWO_BYTE_UTF8_TO_UNI(*scan,
6989                                                                    *(scan + 1)),
6990                                                     classnum))))
6991                         {
6992                             break;
6993                         }
6994                         scan += 2;
6995                     }
6996                     else {
6997                         goto found_above_latin1;
6998                     }
6999 
7000                     hardcount++;
7001                 }
7002             }
7003             else {
7004                 /* For these character classes, the knowledge of how to handle
7005                  * every code point is compiled in to Perl via a macro.  This
7006                  * code is written for making the loops as tight as possible.
7007                  * It could be refactored to save space instead */
7008                 switch (classnum) {
7009                     case _CC_ENUM_SPACE:    /* XXX would require separate code
7010                                                if we revert the change of \v
7011                                                matching this */
7012                         /* FALL THROUGH */
7013                     case _CC_ENUM_PSXSPC:
7014                         while (hardcount < max
7015                                && scan < loceol
7016                                && (to_complement ^ cBOOL(isSPACE_utf8(scan))))
7017                         {
7018                             scan += UTF8SKIP(scan);
7019                             hardcount++;
7020                         }
7021                         break;
7022                     case _CC_ENUM_BLANK:
7023                         while (hardcount < max
7024                                && scan < loceol
7025                                && (to_complement ^ cBOOL(isBLANK_utf8(scan))))
7026                         {
7027                             scan += UTF8SKIP(scan);
7028                             hardcount++;
7029                         }
7030                         break;
7031                     case _CC_ENUM_XDIGIT:
7032                         while (hardcount < max
7033                                && scan < loceol
7034                                && (to_complement ^ cBOOL(isXDIGIT_utf8(scan))))
7035                         {
7036                             scan += UTF8SKIP(scan);
7037                             hardcount++;
7038                         }
7039                         break;
7040                     case _CC_ENUM_VERTSPACE:
7041                         while (hardcount < max
7042                                && scan < loceol
7043                                && (to_complement ^ cBOOL(isVERTWS_utf8(scan))))
7044                         {
7045                             scan += UTF8SKIP(scan);
7046                             hardcount++;
7047                         }
7048                         break;
7049                     case _CC_ENUM_CNTRL:
7050                         while (hardcount < max
7051                                && scan < loceol
7052                                && (to_complement ^ cBOOL(isCNTRL_utf8(scan))))
7053                         {
7054                             scan += UTF8SKIP(scan);
7055                             hardcount++;
7056                         }
7057                         break;
7058                     default:
7059                         Perl_croak(aTHX_ "panic: regrepeat() node %d='%s' has an unexpected character class '%d'", OP(p), PL_reg_name[OP(p)], classnum);
7060                 }
7061             }
7062 	}
7063         break;
7064 
7065       found_above_latin1:   /* Continuation of POSIXU and NPOSIXU */
7066 
7067         /* Load the swash if not already present */
7068         if (! PL_utf8_swash_ptrs[classnum]) {
7069             U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
7070             PL_utf8_swash_ptrs[classnum] = _core_swash_init(
7071                                         "utf8", swash_property_names[classnum],
7072                                         &PL_sv_undef, 1, 0, NULL, &flags);
7073         }
7074 
7075         while (hardcount < max && scan < loceol
7076                && to_complement ^ cBOOL(_generic_utf8(
7077                                        classnum,
7078                                        scan,
7079                                        swash_fetch(PL_utf8_swash_ptrs[classnum],
7080                                                    (U8 *) scan,
7081                                                    TRUE))))
7082         {
7083             scan += UTF8SKIP(scan);
7084             hardcount++;
7085         }
7086         break;
7087 
7088     case LNBREAK:
7089         if (utf8_target) {
7090 	    while (hardcount < max && scan < loceol &&
7091                     (c=is_LNBREAK_utf8_safe(scan, loceol))) {
7092 		scan += c;
7093 		hardcount++;
7094 	    }
7095 	} else {
7096             /* LNBREAK can match one or two latin chars, which is ok, but we
7097              * have to use hardcount in this situation, and throw away the
7098              * adjustment to <loceol> done before the switch statement */
7099             loceol = PL_regeol;
7100 	    while (scan < loceol && (c=is_LNBREAK_latin1_safe(scan, loceol))) {
7101 		scan+=c;
7102 		hardcount++;
7103 	    }
7104 	}
7105 	break;
7106 
7107     case BOUND:
7108     case BOUNDA:
7109     case BOUNDL:
7110     case BOUNDU:
7111     case EOS:
7112     case GPOS:
7113     case KEEPS:
7114     case NBOUND:
7115     case NBOUNDA:
7116     case NBOUNDL:
7117     case NBOUNDU:
7118     case OPFAIL:
7119     case SBOL:
7120     case SEOL:
7121         /* These are all 0 width, so match right here or not at all. */
7122         break;
7123 
7124     default:
7125         Perl_croak(aTHX_ "panic: regrepeat() called with unrecognized node type %d='%s'", OP(p), PL_reg_name[OP(p)]);
7126         assert(0); /* NOTREACHED */
7127 
7128     }
7129 
7130     if (hardcount)
7131 	c = hardcount;
7132     else
7133 	c = scan - *startposp;
7134     *startposp = scan;
7135 
7136     DEBUG_r({
7137 	GET_RE_DEBUG_FLAGS_DECL;
7138 	DEBUG_EXECUTE_r({
7139 	    SV * const prop = sv_newmortal();
7140 	    regprop(prog, prop, p);
7141 	    PerlIO_printf(Perl_debug_log,
7142 			"%*s  %s can match %"IVdf" times out of %"IVdf"...\n",
7143 			REPORT_CODE_OFF + depth*2, "", SvPVX_const(prop),(IV)c,(IV)max);
7144 	});
7145     });
7146 
7147     return(c);
7148 }
7149 
7150 
7151 #if !defined(PERL_IN_XSUB_RE) || defined(PLUGGABLE_RE_EXTENSION)
7152 /*
7153 - regclass_swash - prepare the utf8 swash.  Wraps the shared core version to
7154 create a copy so that changes the caller makes won't change the shared one.
7155 If <altsvp> is non-null, will return NULL in it, for back-compat.
7156  */
7157 SV *
7158 Perl_regclass_swash(pTHX_ const regexp *prog, const regnode* node, bool doinit, SV** listsvp, SV **altsvp)
7159 {
7160     PERL_ARGS_ASSERT_REGCLASS_SWASH;
7161 
7162     if (altsvp) {
7163         *altsvp = NULL;
7164     }
7165 
7166     return newSVsv(core_regclass_swash(prog, node, doinit, listsvp));
7167 }
7168 #endif
7169 
7170 STATIC SV *
7171 S_core_regclass_swash(pTHX_ const regexp *prog, const regnode* node, bool doinit, SV** listsvp)
7172 {
7173     /* Returns the swash for the input 'node' in the regex 'prog'.
7174      * If <doinit> is true, will attempt to create the swash if not already
7175      *	  done.
7176      * If <listsvp> is non-null, will return the swash initialization string in
7177      *	  it.
7178      * Tied intimately to how regcomp.c sets up the data structure */
7179 
7180     dVAR;
7181     SV *sw  = NULL;
7182     SV *si  = NULL;
7183     SV*  invlist = NULL;
7184 
7185     RXi_GET_DECL(prog,progi);
7186     const struct reg_data * const data = prog ? progi->data : NULL;
7187 
7188     PERL_ARGS_ASSERT_CORE_REGCLASS_SWASH;
7189 
7190     assert(ANYOF_NONBITMAP(node));
7191 
7192     if (data && data->count) {
7193 	const U32 n = ARG(node);
7194 
7195 	if (data->what[n] == 's') {
7196 	    SV * const rv = MUTABLE_SV(data->data[n]);
7197 	    AV * const av = MUTABLE_AV(SvRV(rv));
7198 	    SV **const ary = AvARRAY(av);
7199 	    U8 swash_init_flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
7200 
7201 	    si = *ary;	/* ary[0] = the string to initialize the swash with */
7202 
7203 	    /* Elements 2 and 3 are either both present or both absent. [2] is
7204 	     * any inversion list generated at compile time; [3] indicates if
7205 	     * that inversion list has any user-defined properties in it. */
7206 	    if (av_len(av) >= 2) {
7207 		invlist = ary[2];
7208 		if (SvUV(ary[3])) {
7209                     swash_init_flags |= _CORE_SWASH_INIT_USER_DEFINED_PROPERTY;
7210                 }
7211 	    }
7212 	    else {
7213 		invlist = NULL;
7214 	    }
7215 
7216 	    /* Element [1] is reserved for the set-up swash.  If already there,
7217 	     * return it; if not, create it and store it there */
7218 	    if (SvROK(ary[1])) {
7219 		sw = ary[1];
7220 	    }
7221 	    else if (si && doinit) {
7222 
7223 		sw = _core_swash_init("utf8", /* the utf8 package */
7224 				      "", /* nameless */
7225 				      si,
7226 				      1, /* binary */
7227 				      0, /* not from tr/// */
7228 				      invlist,
7229 				      &swash_init_flags);
7230 		(void)av_store(av, 1, sw);
7231 	    }
7232 	}
7233     }
7234 
7235     if (listsvp) {
7236 	SV* matches_string = newSVpvn("", 0);
7237 
7238 	/* Use the swash, if any, which has to have incorporated into it all
7239 	 * possibilities */
7240 	if ((! sw || (invlist = _get_swash_invlist(sw)) == NULL)
7241             && (si && si != &PL_sv_undef))
7242         {
7243 
7244 	    /* If no swash, use the input initialization string, if available */
7245 	    sv_catsv(matches_string, si);
7246 	}
7247 
7248 	/* Add the inversion list to whatever we have.  This may have come from
7249 	 * the swash, or from an input parameter */
7250 	if (invlist) {
7251 	    sv_catsv(matches_string, _invlist_contents(invlist));
7252 	}
7253 	*listsvp = matches_string;
7254     }
7255 
7256     return sw;
7257 }
7258 
7259 /*
7260  - reginclass - determine if a character falls into a character class
7261 
7262   n is the ANYOF regnode
7263   p is the target string
7264   utf8_target tells whether p is in UTF-8.
7265 
7266   Returns true if matched; false otherwise.
7267 
7268   Note that this can be a synthetic start class, a combination of various
7269   nodes, so things you think might be mutually exclusive, such as locale,
7270   aren't.  It can match both locale and non-locale
7271 
7272  */
7273 
7274 STATIC bool
7275 S_reginclass(pTHX_ regexp * const prog, const regnode * const n, const U8* const p, const bool utf8_target)
7276 {
7277     dVAR;
7278     const char flags = ANYOF_FLAGS(n);
7279     bool match = FALSE;
7280     UV c = *p;
7281 
7282     PERL_ARGS_ASSERT_REGINCLASS;
7283 
7284     /* If c is not already the code point, get it.  Note that
7285      * UTF8_IS_INVARIANT() works even if not in UTF-8 */
7286     if (! UTF8_IS_INVARIANT(c) && utf8_target) {
7287         STRLEN c_len = 0;
7288 	c = utf8n_to_uvchr(p, UTF8_MAXBYTES, &c_len,
7289 		(UTF8_ALLOW_DEFAULT & UTF8_ALLOW_ANYUV)
7290 		| UTF8_ALLOW_FFFF | UTF8_CHECK_ONLY);
7291 		/* see [perl #37836] for UTF8_ALLOW_ANYUV; [perl #38293] for
7292 		 * UTF8_ALLOW_FFFF */
7293 	if (c_len == (STRLEN)-1)
7294 	    Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
7295     }
7296 
7297     /* If this character is potentially in the bitmap, check it */
7298     if (c < 256) {
7299 	if (ANYOF_BITMAP_TEST(n, c))
7300 	    match = TRUE;
7301 	else if (flags & ANYOF_NON_UTF8_LATIN1_ALL
7302 		&& ! utf8_target
7303 		&& ! isASCII(c))
7304 	{
7305 	    match = TRUE;
7306 	}
7307 	else if (flags & ANYOF_LOCALE) {
7308 	    RXp_MATCH_TAINTED_on(prog);
7309 
7310 	    if ((flags & ANYOF_LOC_FOLD)
7311 		 && ANYOF_BITMAP_TEST(n, PL_fold_locale[c]))
7312 	    {
7313 		match = TRUE;
7314 	    }
7315 	    else if (ANYOF_CLASS_TEST_ANY_SET(n)) {
7316 
7317                 /* The data structure is arranged so bits 0, 2, 4, ... are set
7318                  * if the class includes the Posix character class given by
7319                  * bit/2; and 1, 3, 5, ... are set if the class includes the
7320                  * complemented Posix class given by int(bit/2).  So we loop
7321                  * through the bits, each time changing whether we complement
7322                  * the result or not.  Suppose for the sake of illustration
7323                  * that bits 0-3 mean respectively, \w, \W, \s, \S.  If bit 0
7324                  * is set, it means there is a match for this ANYOF node if the
7325                  * character is in the class given by the expression (0 / 2 = 0
7326                  * = \w).  If it is in that class, isFOO_lc() will return 1,
7327                  * and since 'to_complement' is 0, the result will stay TRUE,
7328                  * and we exit the loop.  Suppose instead that bit 0 is 0, but
7329                  * bit 1 is 1.  That means there is a match if the character
7330                  * matches \W.  We won't bother to call isFOO_lc() on bit 0,
7331                  * but will on bit 1.  On the second iteration 'to_complement'
7332                  * will be 1, so the exclusive or will reverse things, so we
7333                  * are testing for \W.  On the third iteration, 'to_complement'
7334                  * will be 0, and we would be testing for \s; the fourth
7335                  * iteration would test for \S, etc.
7336                  *
7337                  * Note that this code assumes that all the classes are closed
7338                  * under folding.  For example, if a character matches \w, then
7339                  * its fold does too; and vice versa.  This should be true for
7340                  * any well-behaved locale for all the currently defined Posix
7341                  * classes, except for :lower: and :upper:, which are handled
7342                  * by the pseudo-class :cased: which matches if either of the
7343                  * other two does.  To get rid of this assumption, an outer
7344                  * loop could be used below to iterate over both the source
7345                  * character, and its fold (if different) */
7346 
7347                 int count = 0;
7348                 int to_complement = 0;
7349                 while (count < ANYOF_MAX) {
7350                     if (ANYOF_CLASS_TEST(n, count)
7351                         && to_complement ^ cBOOL(isFOO_lc(count/2, (U8) c)))
7352                     {
7353                         match = TRUE;
7354                         break;
7355                     }
7356                     count++;
7357                     to_complement ^= 1;
7358                 }
7359 	    }
7360 	}
7361     }
7362 
7363     /* If the bitmap didn't (or couldn't) match, and something outside the
7364      * bitmap could match, try that.  Locale nodes specify completely the
7365      * behavior of code points in the bit map (otherwise, a utf8 target would
7366      * cause them to be treated as Unicode and not locale), except in
7367      * the very unlikely event when this node is a synthetic start class, which
7368      * could be a combination of locale and non-locale nodes.  So allow locale
7369      * to match for the synthetic start class, which will give a false
7370      * positive that will be resolved when the match is done again as not part
7371      * of the synthetic start class */
7372     if (!match) {
7373 	if (utf8_target && (flags & ANYOF_UNICODE_ALL) && c >= 256) {
7374 	    match = TRUE;	/* Everything above 255 matches */
7375 	}
7376 	else if (ANYOF_NONBITMAP(n)
7377 		 && ((flags & ANYOF_NONBITMAP_NON_UTF8)
7378 		     || (utf8_target
7379 		         && (c >=256
7380 			     || (! (flags & ANYOF_LOCALE))
7381 			     || OP(n) == ANYOF_SYNTHETIC))))
7382 	{
7383 	    SV * const sw = core_regclass_swash(prog, n, TRUE, 0);
7384 	    if (sw) {
7385 		U8 * utf8_p;
7386 		if (utf8_target) {
7387 		    utf8_p = (U8 *) p;
7388 		} else { /* Convert to utf8 */
7389 		    STRLEN len = 1;
7390 		    utf8_p = bytes_to_utf8(p, &len);
7391 		}
7392 
7393 		if (swash_fetch(sw, utf8_p, TRUE)) {
7394 		    match = TRUE;
7395                 }
7396 
7397 		/* If we allocated a string above, free it */
7398 		if (! utf8_target) Safefree(utf8_p);
7399 	    }
7400 	}
7401 
7402         if (UNICODE_IS_SUPER(c)
7403             && OP(n) == ANYOF_WARN_SUPER
7404             && ckWARN_d(WARN_NON_UNICODE))
7405         {
7406             Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
7407                 "Code point 0x%04"UVXf" is not Unicode, all \\p{} matches fail; all \\P{} matches succeed", c);
7408         }
7409     }
7410 
7411     /* The xor complements the return if to invert: 1^1 = 0, 1^0 = 1 */
7412     return cBOOL(flags & ANYOF_INVERT) ^ match;
7413 }
7414 
7415 STATIC U8 *
7416 S_reghop3(U8 *s, I32 off, const U8* lim)
7417 {
7418     /* return the position 'off' UTF-8 characters away from 's', forward if
7419      * 'off' >= 0, backwards if negative.  But don't go outside of position
7420      * 'lim', which better be < s  if off < 0 */
7421 
7422     dVAR;
7423 
7424     PERL_ARGS_ASSERT_REGHOP3;
7425 
7426     if (off >= 0) {
7427 	while (off-- && s < lim) {
7428 	    /* XXX could check well-formedness here */
7429 	    s += UTF8SKIP(s);
7430 	}
7431     }
7432     else {
7433         while (off++ && s > lim) {
7434             s--;
7435             if (UTF8_IS_CONTINUED(*s)) {
7436                 while (s > lim && UTF8_IS_CONTINUATION(*s))
7437                     s--;
7438 	    }
7439             /* XXX could check well-formedness here */
7440 	}
7441     }
7442     return s;
7443 }
7444 
7445 #ifdef XXX_dmq
7446 /* there are a bunch of places where we use two reghop3's that should
7447    be replaced with this routine. but since thats not done yet
7448    we ifdef it out - dmq
7449 */
7450 STATIC U8 *
7451 S_reghop4(U8 *s, I32 off, const U8* llim, const U8* rlim)
7452 {
7453     dVAR;
7454 
7455     PERL_ARGS_ASSERT_REGHOP4;
7456 
7457     if (off >= 0) {
7458         while (off-- && s < rlim) {
7459             /* XXX could check well-formedness here */
7460             s += UTF8SKIP(s);
7461         }
7462     }
7463     else {
7464         while (off++ && s > llim) {
7465             s--;
7466             if (UTF8_IS_CONTINUED(*s)) {
7467                 while (s > llim && UTF8_IS_CONTINUATION(*s))
7468                     s--;
7469             }
7470             /* XXX could check well-formedness here */
7471         }
7472     }
7473     return s;
7474 }
7475 #endif
7476 
7477 STATIC U8 *
7478 S_reghopmaybe3(U8* s, I32 off, const U8* lim)
7479 {
7480     dVAR;
7481 
7482     PERL_ARGS_ASSERT_REGHOPMAYBE3;
7483 
7484     if (off >= 0) {
7485 	while (off-- && s < lim) {
7486 	    /* XXX could check well-formedness here */
7487 	    s += UTF8SKIP(s);
7488 	}
7489 	if (off >= 0)
7490 	    return NULL;
7491     }
7492     else {
7493         while (off++ && s > lim) {
7494             s--;
7495             if (UTF8_IS_CONTINUED(*s)) {
7496                 while (s > lim && UTF8_IS_CONTINUATION(*s))
7497                     s--;
7498 	    }
7499             /* XXX could check well-formedness here */
7500 	}
7501 	if (off <= 0)
7502 	    return NULL;
7503     }
7504     return s;
7505 }
7506 
7507 static void
7508 restore_pos(pTHX_ void *arg)
7509 {
7510     dVAR;
7511     regexp * const rex = (regexp *)arg;
7512     if (PL_reg_state.re_state_eval_setup_done) {
7513 	if (PL_reg_oldsaved) {
7514 	    rex->subbeg = PL_reg_oldsaved;
7515 	    rex->sublen = PL_reg_oldsavedlen;
7516 	    rex->suboffset = PL_reg_oldsavedoffset;
7517 	    rex->subcoffset = PL_reg_oldsavedcoffset;
7518 #ifdef PERL_ANY_COW
7519 	    rex->saved_copy = PL_nrs;
7520 #endif
7521 	    RXp_MATCH_COPIED_on(rex);
7522 	}
7523 	PL_reg_magic->mg_len = PL_reg_oldpos;
7524 	PL_reg_state.re_state_eval_setup_done = FALSE;
7525 	PL_curpm = PL_reg_oldcurpm;
7526     }
7527 }
7528 
7529 STATIC void
7530 S_to_utf8_substr(pTHX_ regexp *prog)
7531 {
7532     /* Converts substr fields in prog from bytes to UTF-8, calling fbm_compile
7533      * on the converted value */
7534 
7535     int i = 1;
7536 
7537     PERL_ARGS_ASSERT_TO_UTF8_SUBSTR;
7538 
7539     do {
7540 	if (prog->substrs->data[i].substr
7541 	    && !prog->substrs->data[i].utf8_substr) {
7542 	    SV* const sv = newSVsv(prog->substrs->data[i].substr);
7543 	    prog->substrs->data[i].utf8_substr = sv;
7544 	    sv_utf8_upgrade(sv);
7545 	    if (SvVALID(prog->substrs->data[i].substr)) {
7546 		if (SvTAIL(prog->substrs->data[i].substr)) {
7547 		    /* Trim the trailing \n that fbm_compile added last
7548 		       time.  */
7549 		    SvCUR_set(sv, SvCUR(sv) - 1);
7550 		    /* Whilst this makes the SV technically "invalid" (as its
7551 		       buffer is no longer followed by "\0") when fbm_compile()
7552 		       adds the "\n" back, a "\0" is restored.  */
7553 		    fbm_compile(sv, FBMcf_TAIL);
7554 		} else
7555 		    fbm_compile(sv, 0);
7556 	    }
7557 	    if (prog->substrs->data[i].substr == prog->check_substr)
7558 		prog->check_utf8 = sv;
7559 	}
7560     } while (i--);
7561 }
7562 
7563 STATIC bool
7564 S_to_byte_substr(pTHX_ regexp *prog)
7565 {
7566     /* Converts substr fields in prog from UTF-8 to bytes, calling fbm_compile
7567      * on the converted value; returns FALSE if can't be converted. */
7568 
7569     dVAR;
7570     int i = 1;
7571 
7572     PERL_ARGS_ASSERT_TO_BYTE_SUBSTR;
7573 
7574     do {
7575 	if (prog->substrs->data[i].utf8_substr
7576 	    && !prog->substrs->data[i].substr) {
7577 	    SV* sv = newSVsv(prog->substrs->data[i].utf8_substr);
7578 	    if (! sv_utf8_downgrade(sv, TRUE)) {
7579                 return FALSE;
7580             }
7581             if (SvVALID(prog->substrs->data[i].utf8_substr)) {
7582                 if (SvTAIL(prog->substrs->data[i].utf8_substr)) {
7583                     /* Trim the trailing \n that fbm_compile added last
7584                         time.  */
7585                     SvCUR_set(sv, SvCUR(sv) - 1);
7586                     fbm_compile(sv, FBMcf_TAIL);
7587                 } else
7588                     fbm_compile(sv, 0);
7589             }
7590 	    prog->substrs->data[i].substr = sv;
7591 	    if (prog->substrs->data[i].utf8_substr == prog->check_utf8)
7592 		prog->check_substr = sv;
7593 	}
7594     } while (i--);
7595 
7596     return TRUE;
7597 }
7598 
7599 /*
7600  * Local variables:
7601  * c-indentation-style: bsd
7602  * c-basic-offset: 4
7603  * indent-tabs-mode: nil
7604  * End:
7605  *
7606  * ex: set ts=8 sts=4 sw=4 et:
7607  */
7608