xref: /openbsd-src/gnu/usr.bin/perl/utf8.c (revision ae3cb403620ab940fbaabb3055fac045a63d56b7)
1 /*    utf8.c
2  *
3  *    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
4  *    by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  *
9  */
10 
11 /*
12  * 'What a fix!' said Sam.  'That's the one place in all the lands we've ever
13  *  heard of that we don't want to see any closer; and that's the one place
14  *  we're trying to get to!  And that's just where we can't get, nohow.'
15  *
16  *     [p.603 of _The Lord of the Rings_, IV/I: "The Taming of Sméagol"]
17  *
18  * 'Well do I understand your speech,' he answered in the same language;
19  * 'yet few strangers do so.  Why then do you not speak in the Common Tongue,
20  *  as is the custom in the West, if you wish to be answered?'
21  *                           --Gandalf, addressing Théoden's door wardens
22  *
23  *     [p.508 of _The Lord of the Rings_, III/vi: "The King of the Golden Hall"]
24  *
25  * ...the travellers perceived that the floor was paved with stones of many
26  * hues; branching runes and strange devices intertwined beneath their feet.
27  *
28  *     [p.512 of _The Lord of the Rings_, III/vi: "The King of the Golden Hall"]
29  */
30 
31 #include "EXTERN.h"
32 #define PERL_IN_UTF8_C
33 #include "perl.h"
34 #include "invlist_inline.h"
35 
36 static const char unees[] =
37     "Malformed UTF-8 character (unexpected end of string)";
38 static const char cp_above_legal_max[] =
39  "Use of code point 0x%"UVXf" is deprecated; the permissible max is 0x%"UVXf"";
40 
41 #define MAX_NON_DEPRECATED_CP ((UV) (IV_MAX))
42 
43 /*
44 =head1 Unicode Support
45 These are various utility functions for manipulating UTF8-encoded
46 strings.  For the uninitiated, this is a method of representing arbitrary
47 Unicode characters as a variable number of bytes, in such a way that
48 characters in the ASCII range are unmodified, and a zero byte never appears
49 within non-zero characters.
50 
51 =cut
52 */
53 
54 /*
55 =for apidoc is_invariant_string
56 
57 Returns true iff the first C<len> bytes of the string C<s> are the same
58 regardless of the UTF-8 encoding of the string (or UTF-EBCDIC encoding on
59 EBCDIC machines).  That is, if they are UTF-8 invariant.  On ASCII-ish
60 machines, all the ASCII characters and only the ASCII characters fit this
61 definition.  On EBCDIC machines, the ASCII-range characters are invariant, but
62 so also are the C1 controls and C<\c?> (which isn't in the ASCII range on
63 EBCDIC).
64 
65 If C<len> is 0, it will be calculated using C<strlen(s)>, (which means if you
66 use this option, that C<s> can't have embedded C<NUL> characters and has to
67 have a terminating C<NUL> byte).
68 
69 See also L</is_utf8_string>(), L</is_utf8_string_loclen>(), and L</is_utf8_string_loc>().
70 
71 =cut
72 */
73 
74 bool
75 Perl_is_invariant_string(const U8 *s, STRLEN len)
76 {
77     const U8* const send = s + (len ? len : strlen((const char *)s));
78     const U8* x = s;
79 
80     PERL_ARGS_ASSERT_IS_INVARIANT_STRING;
81 
82     for (; x < send; ++x) {
83 	if (!UTF8_IS_INVARIANT(*x))
84 	    break;
85     }
86 
87     return x == send;
88 }
89 
90 /*
91 =for apidoc uvoffuni_to_utf8_flags
92 
93 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
94 Instead, B<Almost all code should use L</uvchr_to_utf8> or
95 L</uvchr_to_utf8_flags>>.
96 
97 This function is like them, but the input is a strict Unicode
98 (as opposed to native) code point.  Only in very rare circumstances should code
99 not be using the native code point.
100 
101 For details, see the description for L</uvchr_to_utf8_flags>.
102 
103 =cut
104 */
105 
106 #define HANDLE_UNICODE_SURROGATE(uv, flags)                         \
107     STMT_START {                                                    \
108         if (flags & UNICODE_WARN_SURROGATE) {                       \
109             Perl_ck_warner_d(aTHX_ packWARN(WARN_SURROGATE),        \
110                                 "UTF-16 surrogate U+%04"UVXf, uv);  \
111         }                                                           \
112         if (flags & UNICODE_DISALLOW_SURROGATE) {                   \
113             return NULL;                                            \
114         }                                                           \
115     } STMT_END;
116 
117 #define HANDLE_UNICODE_NONCHAR(uv, flags)                           \
118     STMT_START {                                                    \
119         if (flags & UNICODE_WARN_NONCHAR) {                         \
120             Perl_ck_warner_d(aTHX_ packWARN(WARN_NONCHAR),          \
121 		 "Unicode non-character U+%04"UVXf" is not "        \
122                  "recommended for open interchange", uv);           \
123         }                                                           \
124         if (flags & UNICODE_DISALLOW_NONCHAR) {                     \
125             return NULL;                                            \
126         }                                                           \
127     } STMT_END;
128 
129 /*  Use shorter names internally in this file */
130 #define SHIFT   UTF_ACCUMULATION_SHIFT
131 #undef  MARK
132 #define MARK    UTF_CONTINUATION_MARK
133 #define MASK    UTF_CONTINUATION_MASK
134 
135 U8 *
136 Perl_uvoffuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
137 {
138     PERL_ARGS_ASSERT_UVOFFUNI_TO_UTF8_FLAGS;
139 
140     if (OFFUNI_IS_INVARIANT(uv)) {
141 	*d++ = LATIN1_TO_NATIVE(uv);
142 	return d;
143     }
144 
145     if (uv <= MAX_UTF8_TWO_BYTE) {
146         *d++ = I8_TO_NATIVE_UTF8(( uv >> SHIFT) | UTF_START_MARK(2));
147         *d++ = I8_TO_NATIVE_UTF8(( uv           & MASK) |   MARK);
148         return d;
149     }
150 
151     /* Not 2-byte; test for and handle 3-byte result.   In the test immediately
152      * below, the 16 is for start bytes E0-EF (which are all the possible ones
153      * for 3 byte characters).  The 2 is for 2 continuation bytes; these each
154      * contribute SHIFT bits.  This yields 0x4000 on EBCDIC platforms, 0x1_0000
155      * on ASCII; so 3 bytes covers the range 0x400-0x3FFF on EBCDIC;
156      * 0x800-0xFFFF on ASCII */
157     if (uv < (16 * (1U << (2 * SHIFT)))) {
158 	*d++ = I8_TO_NATIVE_UTF8(( uv >> ((3 - 1) * SHIFT)) | UTF_START_MARK(3));
159 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((2 - 1) * SHIFT)) & MASK) |   MARK);
160 	*d++ = I8_TO_NATIVE_UTF8(( uv  /* (1 - 1) */        & MASK) |   MARK);
161 
162 #ifndef EBCDIC  /* These problematic code points are 4 bytes on EBCDIC, so
163                    aren't tested here */
164         /* The most likely code points in this range are below the surrogates.
165          * Do an extra test to quickly exclude those. */
166         if (UNLIKELY(uv >= UNICODE_SURROGATE_FIRST)) {
167             if (UNLIKELY(   UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv)
168                          || UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv)))
169             {
170                 HANDLE_UNICODE_NONCHAR(uv, flags);
171             }
172             else if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
173                 HANDLE_UNICODE_SURROGATE(uv, flags);
174             }
175         }
176 #endif
177 	return d;
178     }
179 
180     /* Not 3-byte; that means the code point is at least 0x1_0000 on ASCII
181      * platforms, and 0x4000 on EBCDIC.  There are problematic cases that can
182      * happen starting with 4-byte characters on ASCII platforms.  We unify the
183      * code for these with EBCDIC, even though some of them require 5-bytes on
184      * those, because khw believes the code saving is worth the very slight
185      * performance hit on these high EBCDIC code points. */
186 
187     if (UNLIKELY(UNICODE_IS_SUPER(uv))) {
188         if (   UNLIKELY(uv > MAX_NON_DEPRECATED_CP)
189             && ckWARN_d(WARN_DEPRECATED))
190         {
191             Perl_warner(aTHX_ packWARN(WARN_DEPRECATED),
192                         cp_above_legal_max, uv, MAX_NON_DEPRECATED_CP);
193         }
194         if (   (flags & UNICODE_WARN_SUPER)
195             || (   UNICODE_IS_ABOVE_31_BIT(uv)
196                 && (flags & UNICODE_WARN_ABOVE_31_BIT)))
197         {
198             Perl_ck_warner_d(aTHX_ packWARN(WARN_NON_UNICODE),
199 
200               /* Choose the more dire applicable warning */
201               (UNICODE_IS_ABOVE_31_BIT(uv))
202               ? "Code point 0x%"UVXf" is not Unicode, and not portable"
203               : "Code point 0x%"UVXf" is not Unicode, may not be portable",
204              uv);
205         }
206         if (flags & UNICODE_DISALLOW_SUPER
207             || (   UNICODE_IS_ABOVE_31_BIT(uv)
208                 && (flags & UNICODE_DISALLOW_ABOVE_31_BIT)))
209         {
210             return NULL;
211         }
212     }
213     else if (UNLIKELY(UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv))) {
214         HANDLE_UNICODE_NONCHAR(uv, flags);
215     }
216 
217     /* Test for and handle 4-byte result.   In the test immediately below, the
218      * 8 is for start bytes F0-F7 (which are all the possible ones for 4 byte
219      * characters).  The 3 is for 3 continuation bytes; these each contribute
220      * SHIFT bits.  This yields 0x4_0000 on EBCDIC platforms, 0x20_0000 on
221      * ASCII, so 4 bytes covers the range 0x4000-0x3_FFFF on EBCDIC;
222      * 0x1_0000-0x1F_FFFF on ASCII */
223     if (uv < (8 * (1U << (3 * SHIFT)))) {
224 	*d++ = I8_TO_NATIVE_UTF8(( uv >> ((4 - 1) * SHIFT)) | UTF_START_MARK(4));
225 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((3 - 1) * SHIFT)) & MASK) |   MARK);
226 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((2 - 1) * SHIFT)) & MASK) |   MARK);
227 	*d++ = I8_TO_NATIVE_UTF8(( uv  /* (1 - 1) */        & MASK) |   MARK);
228 
229 #ifdef EBCDIC   /* These were handled on ASCII platforms in the code for 3-byte
230                    characters.  The end-plane non-characters for EBCDIC were
231                    handled just above */
232         if (UNLIKELY(UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv))) {
233             HANDLE_UNICODE_NONCHAR(uv, flags);
234         }
235         else if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
236             HANDLE_UNICODE_SURROGATE(uv, flags);
237         }
238 #endif
239 
240 	return d;
241     }
242 
243     /* Not 4-byte; that means the code point is at least 0x20_0000 on ASCII
244      * platforms, and 0x4000 on EBCDIC.  At this point we switch to a loop
245      * format.  The unrolled version above turns out to not save all that much
246      * time, and at these high code points (well above the legal Unicode range
247      * on ASCII platforms, and well above anything in common use in EBCDIC),
248      * khw believes that less code outweighs slight performance gains. */
249 
250     {
251 	STRLEN len  = OFFUNISKIP(uv);
252 	U8 *p = d+len-1;
253 	while (p > d) {
254 	    *p-- = I8_TO_NATIVE_UTF8((uv & UTF_CONTINUATION_MASK) | UTF_CONTINUATION_MARK);
255 	    uv >>= UTF_ACCUMULATION_SHIFT;
256 	}
257 	*p = I8_TO_NATIVE_UTF8((uv & UTF_START_MASK(len)) | UTF_START_MARK(len));
258 	return d+len;
259     }
260 }
261 
262 /*
263 =for apidoc uvchr_to_utf8
264 
265 Adds the UTF-8 representation of the native code point C<uv> to the end
266 of the string C<d>; C<d> should have at least C<UVCHR_SKIP(uv)+1> (up to
267 C<UTF8_MAXBYTES+1>) free bytes available.  The return value is the pointer to
268 the byte after the end of the new character.  In other words,
269 
270     d = uvchr_to_utf8(d, uv);
271 
272 is the recommended wide native character-aware way of saying
273 
274     *(d++) = uv;
275 
276 This function accepts any UV as input, but very high code points (above
277 C<IV_MAX> on the platform)  will raise a deprecation warning.  This is
278 typically 0x7FFF_FFFF in a 32-bit word.
279 
280 It is possible to forbid or warn on non-Unicode code points, or those that may
281 be problematic by using L</uvchr_to_utf8_flags>.
282 
283 =cut
284 */
285 
286 /* This is also a macro */
287 PERL_CALLCONV U8*       Perl_uvchr_to_utf8(pTHX_ U8 *d, UV uv);
288 
289 U8 *
290 Perl_uvchr_to_utf8(pTHX_ U8 *d, UV uv)
291 {
292     return uvchr_to_utf8(d, uv);
293 }
294 
295 /*
296 =for apidoc uvchr_to_utf8_flags
297 
298 Adds the UTF-8 representation of the native code point C<uv> to the end
299 of the string C<d>; C<d> should have at least C<UVCHR_SKIP(uv)+1> (up to
300 C<UTF8_MAXBYTES+1>) free bytes available.  The return value is the pointer to
301 the byte after the end of the new character.  In other words,
302 
303     d = uvchr_to_utf8_flags(d, uv, flags);
304 
305 or, in most cases,
306 
307     d = uvchr_to_utf8_flags(d, uv, 0);
308 
309 This is the Unicode-aware way of saying
310 
311     *(d++) = uv;
312 
313 If C<flags> is 0, this function accepts any UV as input, but very high code
314 points (above C<IV_MAX> for the platform)  will raise a deprecation warning.
315 This is typically 0x7FFF_FFFF in a 32-bit word.
316 
317 Specifying C<flags> can further restrict what is allowed and not warned on, as
318 follows:
319 
320 If C<uv> is a Unicode surrogate code point and C<UNICODE_WARN_SURROGATE> is set,
321 the function will raise a warning, provided UTF8 warnings are enabled.  If
322 instead C<UNICODE_DISALLOW_SURROGATE> is set, the function will fail and return
323 NULL.  If both flags are set, the function will both warn and return NULL.
324 
325 Similarly, the C<UNICODE_WARN_NONCHAR> and C<UNICODE_DISALLOW_NONCHAR> flags
326 affect how the function handles a Unicode non-character.
327 
328 And likewise, the C<UNICODE_WARN_SUPER> and C<UNICODE_DISALLOW_SUPER> flags
329 affect the handling of code points that are above the Unicode maximum of
330 0x10FFFF.  Languages other than Perl may not be able to accept files that
331 contain these.
332 
333 The flag C<UNICODE_WARN_ILLEGAL_INTERCHANGE> selects all three of
334 the above WARN flags; and C<UNICODE_DISALLOW_ILLEGAL_INTERCHANGE> selects all
335 three DISALLOW flags.
336 
337 Code points above 0x7FFF_FFFF (2**31 - 1) were never specified in any standard,
338 so using them is more problematic than other above-Unicode code points.  Perl
339 invented an extension to UTF-8 to represent the ones above 2**36-1, so it is
340 likely that non-Perl languages will not be able to read files that contain
341 these that written by the perl interpreter; nor would Perl understand files
342 written by something that uses a different extension.  For these reasons, there
343 is a separate set of flags that can warn and/or disallow these extremely high
344 code points, even if other above-Unicode ones are accepted.  These are the
345 C<UNICODE_WARN_ABOVE_31_BIT> and C<UNICODE_DISALLOW_ABOVE_31_BIT> flags.  These
346 are entirely independent from the deprecation warning for code points above
347 C<IV_MAX>.  On 32-bit machines, it will eventually be forbidden to have any
348 code point that needs more than 31 bits to represent.  When that happens,
349 effectively the C<UNICODE_DISALLOW_ABOVE_31_BIT> flag will always be set on
350 32-bit machines.  (Of course C<UNICODE_DISALLOW_SUPER> will treat all
351 above-Unicode code points, including these, as malformations; and
352 C<UNICODE_WARN_SUPER> warns on these.)
353 
354 On EBCDIC platforms starting in Perl v5.24, the Perl extension for representing
355 extremely high code points kicks in at 0x3FFF_FFFF (2**30 -1), which is lower
356 than on ASCII.  Prior to that, code points 2**31 and higher were simply
357 unrepresentable, and a different, incompatible method was used to represent
358 code points between 2**30 and 2**31 - 1.  The flags C<UNICODE_WARN_ABOVE_31_BIT>
359 and C<UNICODE_DISALLOW_ABOVE_31_BIT> have the same function as on ASCII
360 platforms, warning and disallowing 2**31 and higher.
361 
362 =cut
363 */
364 
365 /* This is also a macro */
366 PERL_CALLCONV U8*       Perl_uvchr_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags);
367 
368 U8 *
369 Perl_uvchr_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
370 {
371     return uvchr_to_utf8_flags(d, uv, flags);
372 }
373 
374 /*
375 =for apidoc is_utf8_string
376 
377 Returns true if the first C<len> bytes of string C<s> form a valid
378 UTF-8 string, false otherwise.  If C<len> is 0, it will be calculated
379 using C<strlen(s)> (which means if you use this option, that C<s> can't have
380 embedded C<NUL> characters and has to have a terminating C<NUL> byte).  Note
381 that all characters being ASCII constitute 'a valid UTF-8 string'.
382 
383 See also L</is_invariant_string>(), L</is_utf8_string_loclen>(), and L</is_utf8_string_loc>().
384 
385 =cut
386 */
387 
388 bool
389 Perl_is_utf8_string(const U8 *s, STRLEN len)
390 {
391     const U8* const send = s + (len ? len : strlen((const char *)s));
392     const U8* x = s;
393 
394     PERL_ARGS_ASSERT_IS_UTF8_STRING;
395 
396     while (x < send) {
397         STRLEN len = isUTF8_CHAR(x, send);
398         if (UNLIKELY(! len)) {
399             return FALSE;
400         }
401         x += len;
402     }
403 
404     return TRUE;
405 }
406 
407 /*
408 Implemented as a macro in utf8.h
409 
410 =for apidoc is_utf8_string_loc
411 
412 Like L</is_utf8_string> but stores the location of the failure (in the
413 case of "utf8ness failure") or the location C<s>+C<len> (in the case of
414 "utf8ness success") in the C<ep>.
415 
416 See also L</is_utf8_string_loclen>() and L</is_utf8_string>().
417 
418 =for apidoc is_utf8_string_loclen
419 
420 Like L</is_utf8_string>() but stores the location of the failure (in the
421 case of "utf8ness failure") or the location C<s>+C<len> (in the case of
422 "utf8ness success") in the C<ep>, and the number of UTF-8
423 encoded characters in the C<el>.
424 
425 See also L</is_utf8_string_loc>() and L</is_utf8_string>().
426 
427 =cut
428 */
429 
430 bool
431 Perl_is_utf8_string_loclen(const U8 *s, STRLEN len, const U8 **ep, STRLEN *el)
432 {
433     const U8* const send = s + (len ? len : strlen((const char *)s));
434     const U8* x = s;
435     STRLEN outlen = 0;
436 
437     PERL_ARGS_ASSERT_IS_UTF8_STRING_LOCLEN;
438 
439     while (x < send) {
440         STRLEN len = isUTF8_CHAR(x, send);
441         if (UNLIKELY(! len)) {
442             goto out;
443         }
444         x += len;
445         outlen++;
446     }
447 
448  out:
449     if (el)
450         *el = outlen;
451 
452     if (ep)
453         *ep = x;
454     return (x == send);
455 }
456 
457 /*
458 
459 =for apidoc utf8n_to_uvchr
460 
461 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
462 Most code should use L</utf8_to_uvchr_buf>() rather than call this directly.
463 
464 Bottom level UTF-8 decode routine.
465 Returns the native code point value of the first character in the string C<s>,
466 which is assumed to be in UTF-8 (or UTF-EBCDIC) encoding, and no longer than
467 C<curlen> bytes; C<*retlen> (if C<retlen> isn't NULL) will be set to
468 the length, in bytes, of that character.
469 
470 The value of C<flags> determines the behavior when C<s> does not point to a
471 well-formed UTF-8 character.  If C<flags> is 0, when a malformation is found,
472 zero is returned and C<*retlen> is set so that (S<C<s> + C<*retlen>>) is the
473 next possible position in C<s> that could begin a non-malformed character.
474 Also, if UTF-8 warnings haven't been lexically disabled, a warning is raised.
475 
476 Various ALLOW flags can be set in C<flags> to allow (and not warn on)
477 individual types of malformations, such as the sequence being overlong (that
478 is, when there is a shorter sequence that can express the same code point;
479 overlong sequences are expressly forbidden in the UTF-8 standard due to
480 potential security issues).  Another malformation example is the first byte of
481 a character not being a legal first byte.  See F<utf8.h> for the list of such
482 flags.  For allowed 0 length strings, this function returns 0; for allowed
483 overlong sequences, the computed code point is returned; for all other allowed
484 malformations, the Unicode REPLACEMENT CHARACTER is returned, as these have no
485 determinable reasonable value.
486 
487 The C<UTF8_CHECK_ONLY> flag overrides the behavior when a non-allowed (by other
488 flags) malformation is found.  If this flag is set, the routine assumes that
489 the caller will raise a warning, and this function will silently just set
490 C<retlen> to C<-1> (cast to C<STRLEN>) and return zero.
491 
492 Note that this API requires disambiguation between successful decoding a C<NUL>
493 character, and an error return (unless the C<UTF8_CHECK_ONLY> flag is set), as
494 in both cases, 0 is returned.  To disambiguate, upon a zero return, see if the
495 first byte of C<s> is 0 as well.  If so, the input was a C<NUL>; if not, the
496 input had an error.
497 
498 Certain code points are considered problematic.  These are Unicode surrogates,
499 Unicode non-characters, and code points above the Unicode maximum of 0x10FFFF.
500 By default these are considered regular code points, but certain situations
501 warrant special handling for them.  If C<flags> contains
502 C<UTF8_DISALLOW_ILLEGAL_INTERCHANGE>, all three classes are treated as
503 malformations and handled as such.  The flags C<UTF8_DISALLOW_SURROGATE>,
504 C<UTF8_DISALLOW_NONCHAR>, and C<UTF8_DISALLOW_SUPER> (meaning above the legal
505 Unicode maximum) can be set to disallow these categories individually.
506 
507 The flags C<UTF8_WARN_ILLEGAL_INTERCHANGE>, C<UTF8_WARN_SURROGATE>,
508 C<UTF8_WARN_NONCHAR>, and C<UTF8_WARN_SUPER> will cause warning messages to be
509 raised for their respective categories, but otherwise the code points are
510 considered valid (not malformations).  To get a category to both be treated as
511 a malformation and raise a warning, specify both the WARN and DISALLOW flags.
512 (But note that warnings are not raised if lexically disabled nor if
513 C<UTF8_CHECK_ONLY> is also specified.)
514 
515 It is now deprecated to have very high code points (above C<IV_MAX> on the
516 platforms) and this function will raise a deprecation warning for these (unless
517 such warnings are turned off).  This value, is typically 0x7FFF_FFFF (2**31 -1)
518 in a 32-bit word.
519 
520 Code points above 0x7FFF_FFFF (2**31 - 1) were never specified in any standard,
521 so using them is more problematic than other above-Unicode code points.  Perl
522 invented an extension to UTF-8 to represent the ones above 2**36-1, so it is
523 likely that non-Perl languages will not be able to read files that contain
524 these that written by the perl interpreter; nor would Perl understand files
525 written by something that uses a different extension.  For these reasons, there
526 is a separate set of flags that can warn and/or disallow these extremely high
527 code points, even if other above-Unicode ones are accepted.  These are the
528 C<UTF8_WARN_ABOVE_31_BIT> and C<UTF8_DISALLOW_ABOVE_31_BIT> flags.  These
529 are entirely independent from the deprecation warning for code points above
530 C<IV_MAX>.  On 32-bit machines, it will eventually be forbidden to have any
531 code point that needs more than 31 bits to represent.  When that happens,
532 effectively the C<UTF8_DISALLOW_ABOVE_31_BIT> flag will always be set on
533 32-bit machines.  (Of course C<UTF8_DISALLOW_SUPER> will treat all
534 above-Unicode code points, including these, as malformations; and
535 C<UTF8_WARN_SUPER> warns on these.)
536 
537 On EBCDIC platforms starting in Perl v5.24, the Perl extension for representing
538 extremely high code points kicks in at 0x3FFF_FFFF (2**30 -1), which is lower
539 than on ASCII.  Prior to that, code points 2**31 and higher were simply
540 unrepresentable, and a different, incompatible method was used to represent
541 code points between 2**30 and 2**31 - 1.  The flags C<UTF8_WARN_ABOVE_31_BIT>
542 and C<UTF8_DISALLOW_ABOVE_31_BIT> have the same function as on ASCII
543 platforms, warning and disallowing 2**31 and higher.
544 
545 All other code points corresponding to Unicode characters, including private
546 use and those yet to be assigned, are never considered malformed and never
547 warn.
548 
549 =cut
550 */
551 
552 UV
553 Perl_utf8n_to_uvchr(pTHX_ const U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
554 {
555     const U8 * const s0 = s;
556     U8 overflow_byte = '\0';	/* Save byte in case of overflow */
557     U8 * send;
558     UV uv = *s;
559     STRLEN expectlen;
560     SV* sv = NULL;
561     UV outlier_ret = 0;	/* return value when input is in error or problematic
562 			 */
563     UV pack_warn = 0;	/* Save result of packWARN() for later */
564     bool unexpected_non_continuation = FALSE;
565     bool overflowed = FALSE;
566     bool do_overlong_test = TRUE;   /* May have to skip this test */
567 
568     const char* const malformed_text = "Malformed UTF-8 character";
569 
570     PERL_ARGS_ASSERT_UTF8N_TO_UVCHR;
571 
572     /* The order of malformation tests here is important.  We should consume as
573      * few bytes as possible in order to not skip any valid character.  This is
574      * required by the Unicode Standard (section 3.9 of Unicode 6.0); see also
575      * http://unicode.org/reports/tr36 for more discussion as to why.  For
576      * example, once we've done a UTF8SKIP, we can tell the expected number of
577      * bytes, and could fail right off the bat if the input parameters indicate
578      * that there are too few available.  But it could be that just that first
579      * byte is garbled, and the intended character occupies fewer bytes.  If we
580      * blindly assumed that the first byte is correct, and skipped based on
581      * that number, we could skip over a valid input character.  So instead, we
582      * always examine the sequence byte-by-byte.
583      *
584      * We also should not consume too few bytes, otherwise someone could inject
585      * things.  For example, an input could be deliberately designed to
586      * overflow, and if this code bailed out immediately upon discovering that,
587      * returning to the caller C<*retlen> pointing to the very next byte (one
588      * which is actually part of of the overflowing sequence), that could look
589      * legitimate to the caller, which could discard the initial partial
590      * sequence and process the rest, inappropriately */
591 
592     /* Zero length strings, if allowed, of necessity are zero */
593     if (UNLIKELY(curlen == 0)) {
594 	if (retlen) {
595 	    *retlen = 0;
596 	}
597 
598 	if (flags & UTF8_ALLOW_EMPTY) {
599 	    return 0;
600 	}
601 	if (! (flags & UTF8_CHECK_ONLY)) {
602 	    sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (empty string)", malformed_text));
603 	}
604 	goto malformed;
605     }
606 
607     expectlen = UTF8SKIP(s);
608 
609     /* A well-formed UTF-8 character, as the vast majority of calls to this
610      * function will be for, has this expected length.  For efficiency, set
611      * things up here to return it.  It will be overriden only in those rare
612      * cases where a malformation is found */
613     if (retlen) {
614 	*retlen = expectlen;
615     }
616 
617     /* An invariant is trivially well-formed */
618     if (UTF8_IS_INVARIANT(uv)) {
619 	return uv;
620     }
621 
622     /* A continuation character can't start a valid sequence */
623     if (UNLIKELY(UTF8_IS_CONTINUATION(uv))) {
624 	if (flags & UTF8_ALLOW_CONTINUATION) {
625 	    if (retlen) {
626 		*retlen = 1;
627 	    }
628 	    return UNICODE_REPLACEMENT;
629 	}
630 
631 	if (! (flags & UTF8_CHECK_ONLY)) {
632 	    sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (unexpected continuation byte 0x%02x, with no preceding start byte)", malformed_text, *s0));
633 	}
634 	curlen = 1;
635 	goto malformed;
636     }
637 
638     /* Here is not a continuation byte, nor an invariant.  The only thing left
639      * is a start byte (possibly for an overlong) */
640 
641 #ifdef EBCDIC
642     uv = NATIVE_UTF8_TO_I8(uv);
643 #endif
644 
645     /* Remove the leading bits that indicate the number of bytes in the
646      * character's whole UTF-8 sequence, leaving just the bits that are part of
647      * the value */
648     uv &= UTF_START_MASK(expectlen);
649 
650     /* Now, loop through the remaining bytes in the character's sequence,
651      * accumulating each into the working value as we go.  Be sure to not look
652      * past the end of the input string */
653     send =  (U8*) s0 + ((expectlen <= curlen) ? expectlen : curlen);
654 
655     for (s = s0 + 1; s < send; s++) {
656 	if (LIKELY(UTF8_IS_CONTINUATION(*s))) {
657 	    if (uv & UTF_ACCUMULATION_OVERFLOW_MASK) {
658 
659 		/* The original implementors viewed this malformation as more
660 		 * serious than the others (though I, khw, don't understand
661 		 * why, since other malformations also give very very wrong
662 		 * results), so there is no way to turn off checking for it.
663 		 * Set a flag, but keep going in the loop, so that we absorb
664 		 * the rest of the bytes that comprise the character. */
665 		overflowed = TRUE;
666 		overflow_byte = *s; /* Save for warning message's use */
667 	    }
668 	    uv = UTF8_ACCUMULATE(uv, *s);
669 	}
670 	else {
671 	    /* Here, found a non-continuation before processing all expected
672 	     * bytes.  This byte begins a new character, so quit, even if
673 	     * allowing this malformation. */
674 	    unexpected_non_continuation = TRUE;
675 	    break;
676 	}
677     } /* End of loop through the character's bytes */
678 
679     /* Save how many bytes were actually in the character */
680     curlen = s - s0;
681 
682     /* The loop above finds two types of malformations: non-continuation and/or
683      * overflow.  The non-continuation malformation is really a too-short
684      * malformation, as it means that the current character ended before it was
685      * expected to (being terminated prematurely by the beginning of the next
686      * character, whereas in the too-short malformation there just are too few
687      * bytes available to hold the character.  In both cases, the check below
688      * that we have found the expected number of bytes would fail if executed.)
689      * Thus the non-continuation malformation is really unnecessary, being a
690      * subset of the too-short malformation.  But there may be existing
691      * applications that are expecting the non-continuation type, so we retain
692      * it, and return it in preference to the too-short malformation.  (If this
693      * code were being written from scratch, the two types might be collapsed
694      * into one.)  I, khw, am also giving priority to returning the
695      * non-continuation and too-short malformations over overflow when multiple
696      * ones are present.  I don't know of any real reason to prefer one over
697      * the other, except that it seems to me that multiple-byte errors trumps
698      * errors from a single byte */
699     if (UNLIKELY(unexpected_non_continuation)) {
700 	if (!(flags & UTF8_ALLOW_NON_CONTINUATION)) {
701 	    if (! (flags & UTF8_CHECK_ONLY)) {
702 		if (curlen == 1) {
703 		    sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (unexpected non-continuation byte 0x%02x, immediately after start byte 0x%02x)", malformed_text, *s, *s0));
704 		}
705 		else {
706 		    sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (unexpected non-continuation byte 0x%02x, %d bytes after start byte 0x%02x, expected %d bytes)", malformed_text, *s, (int) curlen, *s0, (int)expectlen));
707 		}
708 	    }
709 	    goto malformed;
710 	}
711 	uv = UNICODE_REPLACEMENT;
712 
713 	/* Skip testing for overlongs, as the REPLACEMENT may not be the same
714 	 * as what the original expectations were. */
715 	do_overlong_test = FALSE;
716 	if (retlen) {
717 	    *retlen = curlen;
718 	}
719     }
720     else if (UNLIKELY(curlen < expectlen)) {
721 	if (! (flags & UTF8_ALLOW_SHORT)) {
722 	    if (! (flags & UTF8_CHECK_ONLY)) {
723 		sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (%d byte%s, need %d, after start byte 0x%02x)", malformed_text, (int)curlen, curlen == 1 ? "" : "s", (int)expectlen, *s0));
724 	    }
725 	    goto malformed;
726 	}
727 	uv = UNICODE_REPLACEMENT;
728 	do_overlong_test = FALSE;
729 	if (retlen) {
730 	    *retlen = curlen;
731 	}
732     }
733 
734     if (UNLIKELY(overflowed)) {
735 	sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (overflow at byte 0x%02x, after start byte 0x%02x)", malformed_text, overflow_byte, *s0));
736 	goto malformed;
737     }
738 
739     if (do_overlong_test
740 	&& expectlen > (STRLEN) OFFUNISKIP(uv)
741 	&& ! (flags & UTF8_ALLOW_LONG))
742     {
743 	/* The overlong malformation has lower precedence than the others.
744 	 * Note that if this malformation is allowed, we return the actual
745 	 * value, instead of the replacement character.  This is because this
746 	 * value is actually well-defined. */
747 	if (! (flags & UTF8_CHECK_ONLY)) {
748 	    sv = sv_2mortal(Perl_newSVpvf(aTHX_ "%s (%d byte%s, need %d, after start byte 0x%02x)", malformed_text, (int)expectlen, expectlen == 1 ? "": "s", OFFUNISKIP(uv), *s0));
749 	}
750 	goto malformed;
751     }
752 
753     /* Here, the input is considered to be well-formed, but it still could be a
754      * problematic code point that is not allowed by the input parameters. */
755     if (uv >= UNICODE_SURROGATE_FIRST /* isn't problematic if < this */
756 	&& ((flags & ( UTF8_DISALLOW_NONCHAR
757                       |UTF8_DISALLOW_SURROGATE
758                       |UTF8_DISALLOW_SUPER
759                       |UTF8_DISALLOW_ABOVE_31_BIT
760 	              |UTF8_WARN_NONCHAR
761                       |UTF8_WARN_SURROGATE
762                       |UTF8_WARN_SUPER
763                       |UTF8_WARN_ABOVE_31_BIT))
764             || (   UNLIKELY(uv > MAX_NON_DEPRECATED_CP)
765                 && ckWARN_d(WARN_DEPRECATED))))
766     {
767 	if (UNICODE_IS_SURROGATE(uv)) {
768 
769             /* By adding UTF8_CHECK_ONLY to the test, we avoid unnecessary
770              * generation of the sv, since no warnings are raised under CHECK */
771 	    if ((flags & (UTF8_WARN_SURROGATE|UTF8_CHECK_ONLY)) == UTF8_WARN_SURROGATE
772 		&& ckWARN_d(WARN_SURROGATE))
773 	    {
774 		sv = sv_2mortal(Perl_newSVpvf(aTHX_ "UTF-16 surrogate U+%04"UVXf"", uv));
775 		pack_warn = packWARN(WARN_SURROGATE);
776 	    }
777 	    if (flags & UTF8_DISALLOW_SURROGATE) {
778 		goto disallowed;
779 	    }
780 	}
781 	else if ((uv > PERL_UNICODE_MAX)) {
782 	    if ((flags & (UTF8_WARN_SUPER|UTF8_CHECK_ONLY)) == UTF8_WARN_SUPER
783                 && ckWARN_d(WARN_NON_UNICODE))
784 	    {
785 		sv = sv_2mortal(Perl_newSVpvf(aTHX_
786                    "Code point 0x%04"UVXf" is not Unicode, may not be portable",
787                    uv));
788 		pack_warn = packWARN(WARN_NON_UNICODE);
789 	    }
790 
791             /* The maximum code point ever specified by a standard was
792              * 2**31 - 1.  Anything larger than that is a Perl extension that
793              * very well may not be understood by other applications (including
794              * earlier perl versions on EBCDIC platforms).  On ASCII platforms,
795              * these code points are indicated by the first UTF-8 byte being
796              * 0xFE or 0xFF.  We test for these after the regular SUPER ones,
797              * and before possibly bailing out, so that the slightly more dire
798              * warning will override the regular one. */
799             if (
800 #ifndef EBCDIC
801                 (*s0 & 0xFE) == 0xFE	/* matches both FE, FF */
802 #else
803                  /* The I8 for 2**31 (U+80000000) is
804                   *   \xFF\xA0\xA0\xA0\xA0\xA0\xA0\xA2\xA0\xA0\xA0\xA0\xA0\xA0
805                   * and it turns out that on all EBCDIC pages recognized that
806                   * the UTF-EBCDIC for that code point is
807                   *   \xFE\x41\x41\x41\x41\x41\x41\x43\x41\x41\x41\x41\x41\x41
808                   * For the next lower code point, the 1047 UTF-EBCDIC is
809                   *   \xFE\x41\x41\x41\x41\x41\x41\x42\x73\x73\x73\x73\x73\x73
810                   * The other code pages differ only in the bytes following
811                   * \x42.  Thus the following works (the minimum continuation
812                   * byte is \x41). */
813                 *s0 == 0xFE && send - s0 > 7 && (   s0[1] > 0x41
814                                                  || s0[2] > 0x41
815                                                  || s0[3] > 0x41
816                                                  || s0[4] > 0x41
817                                                  || s0[5] > 0x41
818                                                  || s0[6] > 0x41
819                                                  || s0[7] > 0x42)
820 #endif
821                 && (flags & (UTF8_WARN_ABOVE_31_BIT|UTF8_WARN_SUPER
822                             |UTF8_DISALLOW_ABOVE_31_BIT)))
823             {
824                 if (  ! (flags & UTF8_CHECK_ONLY)
825                     &&  (flags & (UTF8_WARN_ABOVE_31_BIT|UTF8_WARN_SUPER))
826                     &&  ckWARN_d(WARN_UTF8))
827                 {
828                     sv = sv_2mortal(Perl_newSVpvf(aTHX_
829                         "Code point 0x%"UVXf" is not Unicode, and not portable",
830                         uv));
831                     pack_warn = packWARN(WARN_UTF8);
832                 }
833                 if (flags & UTF8_DISALLOW_ABOVE_31_BIT) {
834                     goto disallowed;
835                 }
836             }
837 
838 	    if (flags & UTF8_DISALLOW_SUPER) {
839 		goto disallowed;
840 	    }
841 
842             /* The deprecated warning overrides any non-deprecated one */
843             if (UNLIKELY(uv > MAX_NON_DEPRECATED_CP) && ckWARN_d(WARN_DEPRECATED))
844             {
845                 sv = sv_2mortal(Perl_newSVpvf(aTHX_ cp_above_legal_max,
846                                               uv, MAX_NON_DEPRECATED_CP));
847                 pack_warn = packWARN(WARN_DEPRECATED);
848             }
849 	}
850 	else if (UNICODE_IS_NONCHAR(uv)) {
851 	    if ((flags & (UTF8_WARN_NONCHAR|UTF8_CHECK_ONLY)) == UTF8_WARN_NONCHAR
852 		&& ckWARN_d(WARN_NONCHAR))
853 	    {
854 		sv = sv_2mortal(Perl_newSVpvf(aTHX_ "Unicode non-character U+%04"UVXf" is not recommended for open interchange", uv));
855 		pack_warn = packWARN(WARN_NONCHAR);
856 	    }
857 	    if (flags & UTF8_DISALLOW_NONCHAR) {
858 		goto disallowed;
859 	    }
860 	}
861 
862 	if (sv) {
863             outlier_ret = uv;   /* Note we don't bother to convert to native,
864                                    as all the outlier code points are the same
865                                    in both ASCII and EBCDIC */
866 	    goto do_warn;
867 	}
868 
869 	/* Here, this is not considered a malformed character, so drop through
870 	 * to return it */
871     }
872 
873     return UNI_TO_NATIVE(uv);
874 
875     /* There are three cases which get to beyond this point.  In all 3 cases:
876      * <sv>	    if not null points to a string to print as a warning.
877      * <curlen>	    is what <*retlen> should be set to if UTF8_CHECK_ONLY isn't
878      *		    set.
879      * <outlier_ret> is what return value to use if UTF8_CHECK_ONLY isn't set.
880      *		    This is done by initializing it to 0, and changing it only
881      *		    for case 1).
882      * The 3 cases are:
883      * 1)   The input is valid but problematic, and to be warned about.  The
884      *	    return value is the resultant code point; <*retlen> is set to
885      *	    <curlen>, the number of bytes that comprise the code point.
886      *	    <pack_warn> contains the result of packWARN() for the warning
887      *	    types.  The entry point for this case is the label <do_warn>;
888      * 2)   The input is a valid code point but disallowed by the parameters to
889      *	    this function.  The return value is 0.  If UTF8_CHECK_ONLY is set,
890      *	    <*relen> is -1; otherwise it is <curlen>, the number of bytes that
891      *	    comprise the code point.  <pack_warn> contains the result of
892      *	    packWARN() for the warning types.  The entry point for this case is
893      *	    the label <disallowed>.
894      * 3)   The input is malformed.  The return value is 0.  If UTF8_CHECK_ONLY
895      *	    is set, <*relen> is -1; otherwise it is <curlen>, the number of
896      *	    bytes that comprise the malformation.  All such malformations are
897      *	    assumed to be warning type <utf8>.  The entry point for this case
898      *	    is the label <malformed>.
899      */
900 
901   malformed:
902 
903     if (sv && ckWARN_d(WARN_UTF8)) {
904 	pack_warn = packWARN(WARN_UTF8);
905     }
906 
907   disallowed:
908 
909     if (flags & UTF8_CHECK_ONLY) {
910 	if (retlen)
911 	    *retlen = ((STRLEN) -1);
912 	return 0;
913     }
914 
915   do_warn:
916 
917     if (pack_warn) {	/* <pack_warn> was initialized to 0, and changed only
918 			   if warnings are to be raised. */
919 	const char * const string = SvPVX_const(sv);
920 
921 	if (PL_op)
922 	    Perl_warner(aTHX_ pack_warn, "%s in %s", string,  OP_DESC(PL_op));
923 	else
924 	    Perl_warner(aTHX_ pack_warn, "%s", string);
925     }
926 
927     if (retlen) {
928 	*retlen = curlen;
929     }
930 
931     return outlier_ret;
932 }
933 
934 /*
935 =for apidoc utf8_to_uvchr_buf
936 
937 Returns the native code point of the first character in the string C<s> which
938 is assumed to be in UTF-8 encoding; C<send> points to 1 beyond the end of C<s>.
939 C<*retlen> will be set to the length, in bytes, of that character.
940 
941 If C<s> does not point to a well-formed UTF-8 character and UTF8 warnings are
942 enabled, zero is returned and C<*retlen> is set (if C<retlen> isn't
943 C<NULL>) to -1.  If those warnings are off, the computed value, if well-defined
944 (or the Unicode REPLACEMENT CHARACTER if not), is silently returned, and
945 C<*retlen> is set (if C<retlen> isn't C<NULL>) so that (S<C<s> + C<*retlen>>) is
946 the next possible position in C<s> that could begin a non-malformed character.
947 See L</utf8n_to_uvchr> for details on when the REPLACEMENT CHARACTER is
948 returned.
949 
950 Code points above the platform's C<IV_MAX> will raise a deprecation warning,
951 unless those are turned off.
952 
953 =cut
954 */
955 
956 
957 UV
958 Perl_utf8_to_uvchr_buf(pTHX_ const U8 *s, const U8 *send, STRLEN *retlen)
959 {
960     assert(s < send);
961 
962     return utf8n_to_uvchr(s, send - s, retlen,
963 			  ckWARN_d(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
964 }
965 
966 /* Like L</utf8_to_uvchr_buf>(), but should only be called when it is known that
967  * there are no malformations in the input UTF-8 string C<s>.  surrogates,
968  * non-character code points, and non-Unicode code points are allowed. */
969 
970 UV
971 Perl_valid_utf8_to_uvchr(pTHX_ const U8 *s, STRLEN *retlen)
972 {
973     UV expectlen = UTF8SKIP(s);
974     const U8* send = s + expectlen;
975     UV uv = *s;
976 
977     PERL_ARGS_ASSERT_VALID_UTF8_TO_UVCHR;
978     PERL_UNUSED_CONTEXT;
979 
980     if (retlen) {
981         *retlen = expectlen;
982     }
983 
984     /* An invariant is trivially returned */
985     if (expectlen == 1) {
986 	return uv;
987     }
988 
989 #ifdef EBCDIC
990     uv = NATIVE_UTF8_TO_I8(uv);
991 #endif
992 
993     /* Remove the leading bits that indicate the number of bytes, leaving just
994      * the bits that are part of the value */
995     uv &= UTF_START_MASK(expectlen);
996 
997     /* Now, loop through the remaining bytes, accumulating each into the
998      * working total as we go.  (I khw tried unrolling the loop for up to 4
999      * bytes, but there was no performance improvement) */
1000     for (++s; s < send; s++) {
1001         uv = UTF8_ACCUMULATE(uv, *s);
1002     }
1003 
1004     return UNI_TO_NATIVE(uv);
1005 
1006 }
1007 
1008 /*
1009 =for apidoc utf8_to_uvuni_buf
1010 
1011 Only in very rare circumstances should code need to be dealing in Unicode
1012 (as opposed to native) code points.  In those few cases, use
1013 C<L<NATIVE_TO_UNI(utf8_to_uvchr_buf(...))|/utf8_to_uvchr_buf>> instead.
1014 
1015 Returns the Unicode (not-native) code point of the first character in the
1016 string C<s> which
1017 is assumed to be in UTF-8 encoding; C<send> points to 1 beyond the end of C<s>.
1018 C<retlen> will be set to the length, in bytes, of that character.
1019 
1020 If C<s> does not point to a well-formed UTF-8 character and UTF8 warnings are
1021 enabled, zero is returned and C<*retlen> is set (if C<retlen> isn't
1022 NULL) to -1.  If those warnings are off, the computed value if well-defined (or
1023 the Unicode REPLACEMENT CHARACTER, if not) is silently returned, and C<*retlen>
1024 is set (if C<retlen> isn't NULL) so that (S<C<s> + C<*retlen>>) is the
1025 next possible position in C<s> that could begin a non-malformed character.
1026 See L</utf8n_to_uvchr> for details on when the REPLACEMENT CHARACTER is returned.
1027 
1028 Code points above the platform's C<IV_MAX> will raise a deprecation warning,
1029 unless those are turned off.
1030 
1031 =cut
1032 */
1033 
1034 UV
1035 Perl_utf8_to_uvuni_buf(pTHX_ const U8 *s, const U8 *send, STRLEN *retlen)
1036 {
1037     PERL_ARGS_ASSERT_UTF8_TO_UVUNI_BUF;
1038 
1039     assert(send > s);
1040 
1041     /* Call the low level routine asking for checks */
1042     return NATIVE_TO_UNI(Perl_utf8n_to_uvchr(aTHX_ s, send -s, retlen,
1043 			       ckWARN_d(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY));
1044 }
1045 
1046 /*
1047 =for apidoc utf8_length
1048 
1049 Return the length of the UTF-8 char encoded string C<s> in characters.
1050 Stops at C<e> (inclusive).  If C<e E<lt> s> or if the scan would end
1051 up past C<e>, croaks.
1052 
1053 =cut
1054 */
1055 
1056 STRLEN
1057 Perl_utf8_length(pTHX_ const U8 *s, const U8 *e)
1058 {
1059     STRLEN len = 0;
1060 
1061     PERL_ARGS_ASSERT_UTF8_LENGTH;
1062 
1063     /* Note: cannot use UTF8_IS_...() too eagerly here since e.g.
1064      * the bitops (especially ~) can create illegal UTF-8.
1065      * In other words: in Perl UTF-8 is not just for Unicode. */
1066 
1067     if (e < s)
1068 	goto warn_and_return;
1069     while (s < e) {
1070         s += UTF8SKIP(s);
1071 	len++;
1072     }
1073 
1074     if (e != s) {
1075 	len--;
1076         warn_and_return:
1077 	if (PL_op)
1078 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
1079 			     "%s in %s", unees, OP_DESC(PL_op));
1080 	else
1081 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8), "%s", unees);
1082     }
1083 
1084     return len;
1085 }
1086 
1087 /*
1088 =for apidoc utf8_distance
1089 
1090 Returns the number of UTF-8 characters between the UTF-8 pointers C<a>
1091 and C<b>.
1092 
1093 WARNING: use only if you *know* that the pointers point inside the
1094 same UTF-8 buffer.
1095 
1096 =cut
1097 */
1098 
1099 IV
1100 Perl_utf8_distance(pTHX_ const U8 *a, const U8 *b)
1101 {
1102     PERL_ARGS_ASSERT_UTF8_DISTANCE;
1103 
1104     return (a < b) ? -1 * (IV) utf8_length(a, b) : (IV) utf8_length(b, a);
1105 }
1106 
1107 /*
1108 =for apidoc utf8_hop
1109 
1110 Return the UTF-8 pointer C<s> displaced by C<off> characters, either
1111 forward or backward.
1112 
1113 WARNING: do not use the following unless you *know* C<off> is within
1114 the UTF-8 data pointed to by C<s> *and* that on entry C<s> is aligned
1115 on the first byte of character or just after the last byte of a character.
1116 
1117 =cut
1118 */
1119 
1120 U8 *
1121 Perl_utf8_hop(const U8 *s, SSize_t off)
1122 {
1123     PERL_ARGS_ASSERT_UTF8_HOP;
1124 
1125     /* Note: cannot use UTF8_IS_...() too eagerly here since e.g
1126      * the bitops (especially ~) can create illegal UTF-8.
1127      * In other words: in Perl UTF-8 is not just for Unicode. */
1128 
1129     if (off >= 0) {
1130 	while (off--)
1131 	    s += UTF8SKIP(s);
1132     }
1133     else {
1134 	while (off++) {
1135 	    s--;
1136 	    while (UTF8_IS_CONTINUATION(*s))
1137 		s--;
1138 	}
1139     }
1140     return (U8 *)s;
1141 }
1142 
1143 /*
1144 =for apidoc bytes_cmp_utf8
1145 
1146 Compares the sequence of characters (stored as octets) in C<b>, C<blen> with the
1147 sequence of characters (stored as UTF-8)
1148 in C<u>, C<ulen>.  Returns 0 if they are
1149 equal, -1 or -2 if the first string is less than the second string, +1 or +2
1150 if the first string is greater than the second string.
1151 
1152 -1 or +1 is returned if the shorter string was identical to the start of the
1153 longer string.  -2 or +2 is returned if
1154 there was a difference between characters
1155 within the strings.
1156 
1157 =cut
1158 */
1159 
1160 int
1161 Perl_bytes_cmp_utf8(pTHX_ const U8 *b, STRLEN blen, const U8 *u, STRLEN ulen)
1162 {
1163     const U8 *const bend = b + blen;
1164     const U8 *const uend = u + ulen;
1165 
1166     PERL_ARGS_ASSERT_BYTES_CMP_UTF8;
1167 
1168     while (b < bend && u < uend) {
1169         U8 c = *u++;
1170 	if (!UTF8_IS_INVARIANT(c)) {
1171 	    if (UTF8_IS_DOWNGRADEABLE_START(c)) {
1172 		if (u < uend) {
1173 		    U8 c1 = *u++;
1174 		    if (UTF8_IS_CONTINUATION(c1)) {
1175 			c = EIGHT_BIT_UTF8_TO_NATIVE(c, c1);
1176 		    } else {
1177 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
1178 					 "Malformed UTF-8 character "
1179 					 "(unexpected non-continuation byte 0x%02x"
1180 					 ", immediately after start byte 0x%02x)"
1181 					 /* Dear diag.t, it's in the pod.  */
1182 					 "%s%s", c1, c,
1183 					 PL_op ? " in " : "",
1184 					 PL_op ? OP_DESC(PL_op) : "");
1185 			return -2;
1186 		    }
1187 		} else {
1188 		    if (PL_op)
1189 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
1190 					 "%s in %s", unees, OP_DESC(PL_op));
1191 		    else
1192 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8), "%s", unees);
1193 		    return -2; /* Really want to return undef :-)  */
1194 		}
1195 	    } else {
1196 		return -2;
1197 	    }
1198 	}
1199 	if (*b != c) {
1200 	    return *b < c ? -2 : +2;
1201 	}
1202 	++b;
1203     }
1204 
1205     if (b == bend && u == uend)
1206 	return 0;
1207 
1208     return b < bend ? +1 : -1;
1209 }
1210 
1211 /*
1212 =for apidoc utf8_to_bytes
1213 
1214 Converts a string C<s> of length C<len> from UTF-8 into native byte encoding.
1215 Unlike L</bytes_to_utf8>, this over-writes the original string, and
1216 updates C<len> to contain the new length.
1217 Returns zero on failure, setting C<len> to -1.
1218 
1219 If you need a copy of the string, see L</bytes_from_utf8>.
1220 
1221 =cut
1222 */
1223 
1224 U8 *
1225 Perl_utf8_to_bytes(pTHX_ U8 *s, STRLEN *len)
1226 {
1227     U8 * const save = s;
1228     U8 * const send = s + *len;
1229     U8 *d;
1230 
1231     PERL_ARGS_ASSERT_UTF8_TO_BYTES;
1232     PERL_UNUSED_CONTEXT;
1233 
1234     /* ensure valid UTF-8 and chars < 256 before updating string */
1235     while (s < send) {
1236         if (! UTF8_IS_INVARIANT(*s)) {
1237             if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s, send)) {
1238                 *len = ((STRLEN) -1);
1239                 return 0;
1240             }
1241             s++;
1242         }
1243         s++;
1244     }
1245 
1246     d = s = save;
1247     while (s < send) {
1248 	U8 c = *s++;
1249 	if (! UTF8_IS_INVARIANT(c)) {
1250 	    /* Then it is two-byte encoded */
1251 	    c = EIGHT_BIT_UTF8_TO_NATIVE(c, *s);
1252             s++;
1253 	}
1254 	*d++ = c;
1255     }
1256     *d = '\0';
1257     *len = d - save;
1258     return save;
1259 }
1260 
1261 /*
1262 =for apidoc bytes_from_utf8
1263 
1264 Converts a string C<s> of length C<len> from UTF-8 into native byte encoding.
1265 Unlike L</utf8_to_bytes> but like L</bytes_to_utf8>, returns a pointer to
1266 the newly-created string, and updates C<len> to contain the new
1267 length.  Returns the original string if no conversion occurs, C<len>
1268 is unchanged.  Do nothing if C<is_utf8> points to 0.  Sets C<is_utf8> to
1269 0 if C<s> is converted or consisted entirely of characters that are invariant
1270 in UTF-8 (i.e., US-ASCII on non-EBCDIC machines).
1271 
1272 =cut
1273 */
1274 
1275 U8 *
1276 Perl_bytes_from_utf8(pTHX_ const U8 *s, STRLEN *len, bool *is_utf8)
1277 {
1278     U8 *d;
1279     const U8 *start = s;
1280     const U8 *send;
1281     I32 count = 0;
1282 
1283     PERL_ARGS_ASSERT_BYTES_FROM_UTF8;
1284     PERL_UNUSED_CONTEXT;
1285     if (!*is_utf8)
1286         return (U8 *)start;
1287 
1288     /* ensure valid UTF-8 and chars < 256 before converting string */
1289     for (send = s + *len; s < send;) {
1290         if (! UTF8_IS_INVARIANT(*s)) {
1291             if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s, send)) {
1292                 return (U8 *)start;
1293             }
1294             count++;
1295             s++;
1296 	}
1297         s++;
1298     }
1299 
1300     *is_utf8 = FALSE;
1301 
1302     Newx(d, (*len) - count + 1, U8);
1303     s = start; start = d;
1304     while (s < send) {
1305 	U8 c = *s++;
1306 	if (! UTF8_IS_INVARIANT(c)) {
1307 	    /* Then it is two-byte encoded */
1308 	    c = EIGHT_BIT_UTF8_TO_NATIVE(c, *s);
1309             s++;
1310 	}
1311 	*d++ = c;
1312     }
1313     *d = '\0';
1314     *len = d - start;
1315     return (U8 *)start;
1316 }
1317 
1318 /*
1319 =for apidoc bytes_to_utf8
1320 
1321 Converts a string C<s> of length C<len> bytes from the native encoding into
1322 UTF-8.
1323 Returns a pointer to the newly-created string, and sets C<len> to
1324 reflect the new length in bytes.
1325 
1326 A C<NUL> character will be written after the end of the string.
1327 
1328 If you want to convert to UTF-8 from encodings other than
1329 the native (Latin1 or EBCDIC),
1330 see L</sv_recode_to_utf8>().
1331 
1332 =cut
1333 */
1334 
1335 /* This logic is duplicated in sv_catpvn_flags, so any bug fixes will
1336    likewise need duplication. */
1337 
1338 U8*
1339 Perl_bytes_to_utf8(pTHX_ const U8 *s, STRLEN *len)
1340 {
1341     const U8 * const send = s + (*len);
1342     U8 *d;
1343     U8 *dst;
1344 
1345     PERL_ARGS_ASSERT_BYTES_TO_UTF8;
1346     PERL_UNUSED_CONTEXT;
1347 
1348     Newx(d, (*len) * 2 + 1, U8);
1349     dst = d;
1350 
1351     while (s < send) {
1352         append_utf8_from_native_byte(*s, &d);
1353         s++;
1354     }
1355     *d = '\0';
1356     *len = d-dst;
1357     return dst;
1358 }
1359 
1360 /*
1361  * Convert native (big-endian) or reversed (little-endian) UTF-16 to UTF-8.
1362  *
1363  * Destination must be pre-extended to 3/2 source.  Do not use in-place.
1364  * We optimize for native, for obvious reasons. */
1365 
1366 U8*
1367 Perl_utf16_to_utf8(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
1368 {
1369     U8* pend;
1370     U8* dstart = d;
1371 
1372     PERL_ARGS_ASSERT_UTF16_TO_UTF8;
1373 
1374     if (bytelen & 1)
1375 	Perl_croak(aTHX_ "panic: utf16_to_utf8: odd bytelen %"UVuf, (UV)bytelen);
1376 
1377     pend = p + bytelen;
1378 
1379     while (p < pend) {
1380 	UV uv = (p[0] << 8) + p[1]; /* UTF-16BE */
1381 	p += 2;
1382 	if (OFFUNI_IS_INVARIANT(uv)) {
1383 	    *d++ = LATIN1_TO_NATIVE((U8) uv);
1384 	    continue;
1385 	}
1386 	if (uv <= MAX_UTF8_TWO_BYTE) {
1387 	    *d++ = UTF8_TWO_BYTE_HI(UNI_TO_NATIVE(uv));
1388 	    *d++ = UTF8_TWO_BYTE_LO(UNI_TO_NATIVE(uv));
1389 	    continue;
1390 	}
1391 #define FIRST_HIGH_SURROGATE UNICODE_SURROGATE_FIRST
1392 #define LAST_HIGH_SURROGATE  0xDBFF
1393 #define FIRST_LOW_SURROGATE  0xDC00
1394 #define LAST_LOW_SURROGATE   UNICODE_SURROGATE_LAST
1395 
1396         /* This assumes that most uses will be in the first Unicode plane, not
1397          * needing surrogates */
1398 	if (UNLIKELY(uv >= UNICODE_SURROGATE_FIRST
1399                   && uv <= UNICODE_SURROGATE_LAST))
1400         {
1401             if (UNLIKELY(p >= pend) || UNLIKELY(uv > LAST_HIGH_SURROGATE)) {
1402                 Perl_croak(aTHX_ "Malformed UTF-16 surrogate");
1403             }
1404 	    else {
1405 		UV low = (p[0] << 8) + p[1];
1406 		if (   UNLIKELY(low < FIRST_LOW_SURROGATE)
1407                     || UNLIKELY(low > LAST_LOW_SURROGATE))
1408                 {
1409 		    Perl_croak(aTHX_ "Malformed UTF-16 surrogate");
1410                 }
1411 		p += 2;
1412 		uv = ((uv - FIRST_HIGH_SURROGATE) << 10)
1413                                        + (low - FIRST_LOW_SURROGATE) + 0x10000;
1414 	    }
1415 	}
1416 #ifdef EBCDIC
1417         d = uvoffuni_to_utf8_flags(d, uv, 0);
1418 #else
1419 	if (uv < 0x10000) {
1420 	    *d++ = (U8)(( uv >> 12)         | 0xe0);
1421 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
1422 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
1423 	    continue;
1424 	}
1425 	else {
1426 	    *d++ = (U8)(( uv >> 18)         | 0xf0);
1427 	    *d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
1428 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
1429 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
1430 	    continue;
1431 	}
1432 #endif
1433     }
1434     *newlen = d - dstart;
1435     return d;
1436 }
1437 
1438 /* Note: this one is slightly destructive of the source. */
1439 
1440 U8*
1441 Perl_utf16_to_utf8_reversed(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
1442 {
1443     U8* s = (U8*)p;
1444     U8* const send = s + bytelen;
1445 
1446     PERL_ARGS_ASSERT_UTF16_TO_UTF8_REVERSED;
1447 
1448     if (bytelen & 1)
1449 	Perl_croak(aTHX_ "panic: utf16_to_utf8_reversed: odd bytelen %"UVuf,
1450 		   (UV)bytelen);
1451 
1452     while (s < send) {
1453 	const U8 tmp = s[0];
1454 	s[0] = s[1];
1455 	s[1] = tmp;
1456 	s += 2;
1457     }
1458     return utf16_to_utf8(p, d, bytelen, newlen);
1459 }
1460 
1461 bool
1462 Perl__is_uni_FOO(pTHX_ const U8 classnum, const UV c)
1463 {
1464     U8 tmpbuf[UTF8_MAXBYTES+1];
1465     uvchr_to_utf8(tmpbuf, c);
1466     return _is_utf8_FOO(classnum, tmpbuf);
1467 }
1468 
1469 /* Internal function so we can deprecate the external one, and call
1470    this one from other deprecated functions in this file */
1471 
1472 bool
1473 Perl__is_utf8_idstart(pTHX_ const U8 *p)
1474 {
1475     PERL_ARGS_ASSERT__IS_UTF8_IDSTART;
1476 
1477     if (*p == '_')
1478 	return TRUE;
1479     return is_utf8_common(p, &PL_utf8_idstart, "IdStart", NULL);
1480 }
1481 
1482 bool
1483 Perl__is_uni_perl_idcont(pTHX_ UV c)
1484 {
1485     U8 tmpbuf[UTF8_MAXBYTES+1];
1486     uvchr_to_utf8(tmpbuf, c);
1487     return _is_utf8_perl_idcont(tmpbuf);
1488 }
1489 
1490 bool
1491 Perl__is_uni_perl_idstart(pTHX_ UV c)
1492 {
1493     U8 tmpbuf[UTF8_MAXBYTES+1];
1494     uvchr_to_utf8(tmpbuf, c);
1495     return _is_utf8_perl_idstart(tmpbuf);
1496 }
1497 
1498 UV
1499 Perl__to_upper_title_latin1(pTHX_ const U8 c, U8* p, STRLEN *lenp, const char S_or_s)
1500 {
1501     /* We have the latin1-range values compiled into the core, so just use
1502      * those, converting the result to UTF-8.  The only difference between upper
1503      * and title case in this range is that LATIN_SMALL_LETTER_SHARP_S is
1504      * either "SS" or "Ss".  Which one to use is passed into the routine in
1505      * 'S_or_s' to avoid a test */
1506 
1507     UV converted = toUPPER_LATIN1_MOD(c);
1508 
1509     PERL_ARGS_ASSERT__TO_UPPER_TITLE_LATIN1;
1510 
1511     assert(S_or_s == 'S' || S_or_s == 's');
1512 
1513     if (UVCHR_IS_INVARIANT(converted)) { /* No difference between the two for
1514 					     characters in this range */
1515 	*p = (U8) converted;
1516 	*lenp = 1;
1517 	return converted;
1518     }
1519 
1520     /* toUPPER_LATIN1_MOD gives the correct results except for three outliers,
1521      * which it maps to one of them, so as to only have to have one check for
1522      * it in the main case */
1523     if (UNLIKELY(converted == LATIN_SMALL_LETTER_Y_WITH_DIAERESIS)) {
1524 	switch (c) {
1525 	    case LATIN_SMALL_LETTER_Y_WITH_DIAERESIS:
1526 		converted = LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS;
1527 		break;
1528 	    case MICRO_SIGN:
1529 		converted = GREEK_CAPITAL_LETTER_MU;
1530 		break;
1531 #if    UNICODE_MAJOR_VERSION > 2                                        \
1532    || (UNICODE_MAJOR_VERSION == 2 && UNICODE_DOT_VERSION >= 1           \
1533                                   && UNICODE_DOT_DOT_VERSION >= 8)
1534 	    case LATIN_SMALL_LETTER_SHARP_S:
1535 		*(p)++ = 'S';
1536 		*p = S_or_s;
1537 		*lenp = 2;
1538 		return 'S';
1539 #endif
1540 	    default:
1541 		Perl_croak(aTHX_ "panic: to_upper_title_latin1 did not expect '%c' to map to '%c'", c, LATIN_SMALL_LETTER_Y_WITH_DIAERESIS);
1542 		NOT_REACHED; /* NOTREACHED */
1543 	}
1544     }
1545 
1546     *(p)++ = UTF8_TWO_BYTE_HI(converted);
1547     *p = UTF8_TWO_BYTE_LO(converted);
1548     *lenp = 2;
1549 
1550     return converted;
1551 }
1552 
1553 /* Call the function to convert a UTF-8 encoded character to the specified case.
1554  * Note that there may be more than one character in the result.
1555  * INP is a pointer to the first byte of the input character
1556  * OUTP will be set to the first byte of the string of changed characters.  It
1557  *	needs to have space for UTF8_MAXBYTES_CASE+1 bytes
1558  * LENP will be set to the length in bytes of the string of changed characters
1559  *
1560  * The functions return the ordinal of the first character in the string of OUTP */
1561 #define CALL_UPPER_CASE(uv, s, d, lenp) _to_utf8_case(uv, s, d, lenp, &PL_utf8_toupper, "ToUc", "")
1562 #define CALL_TITLE_CASE(uv, s, d, lenp) _to_utf8_case(uv, s, d, lenp, &PL_utf8_totitle, "ToTc", "")
1563 #define CALL_LOWER_CASE(uv, s, d, lenp) _to_utf8_case(uv, s, d, lenp, &PL_utf8_tolower, "ToLc", "")
1564 
1565 /* This additionally has the input parameter 'specials', which if non-zero will
1566  * cause this to use the specials hash for folding (meaning get full case
1567  * folding); otherwise, when zero, this implies a simple case fold */
1568 #define CALL_FOLD_CASE(uv, s, d, lenp, specials) _to_utf8_case(uv, s, d, lenp, &PL_utf8_tofold, "ToCf", (specials) ? "" : NULL)
1569 
1570 UV
1571 Perl_to_uni_upper(pTHX_ UV c, U8* p, STRLEN *lenp)
1572 {
1573     /* Convert the Unicode character whose ordinal is <c> to its uppercase
1574      * version and store that in UTF-8 in <p> and its length in bytes in <lenp>.
1575      * Note that the <p> needs to be at least UTF8_MAXBYTES_CASE+1 bytes since
1576      * the changed version may be longer than the original character.
1577      *
1578      * The ordinal of the first character of the changed version is returned
1579      * (but note, as explained above, that there may be more.) */
1580 
1581     PERL_ARGS_ASSERT_TO_UNI_UPPER;
1582 
1583     if (c < 256) {
1584 	return _to_upper_title_latin1((U8) c, p, lenp, 'S');
1585     }
1586 
1587     uvchr_to_utf8(p, c);
1588     return CALL_UPPER_CASE(c, p, p, lenp);
1589 }
1590 
1591 UV
1592 Perl_to_uni_title(pTHX_ UV c, U8* p, STRLEN *lenp)
1593 {
1594     PERL_ARGS_ASSERT_TO_UNI_TITLE;
1595 
1596     if (c < 256) {
1597 	return _to_upper_title_latin1((U8) c, p, lenp, 's');
1598     }
1599 
1600     uvchr_to_utf8(p, c);
1601     return CALL_TITLE_CASE(c, p, p, lenp);
1602 }
1603 
1604 STATIC U8
1605 S_to_lower_latin1(const U8 c, U8* p, STRLEN *lenp)
1606 {
1607     /* We have the latin1-range values compiled into the core, so just use
1608      * those, converting the result to UTF-8.  Since the result is always just
1609      * one character, we allow <p> to be NULL */
1610 
1611     U8 converted = toLOWER_LATIN1(c);
1612 
1613     if (p != NULL) {
1614 	if (NATIVE_BYTE_IS_INVARIANT(converted)) {
1615 	    *p = converted;
1616 	    *lenp = 1;
1617 	}
1618 	else {
1619             /* Result is known to always be < 256, so can use the EIGHT_BIT
1620              * macros */
1621 	    *p = UTF8_EIGHT_BIT_HI(converted);
1622 	    *(p+1) = UTF8_EIGHT_BIT_LO(converted);
1623 	    *lenp = 2;
1624 	}
1625     }
1626     return converted;
1627 }
1628 
1629 UV
1630 Perl_to_uni_lower(pTHX_ UV c, U8* p, STRLEN *lenp)
1631 {
1632     PERL_ARGS_ASSERT_TO_UNI_LOWER;
1633 
1634     if (c < 256) {
1635 	return to_lower_latin1((U8) c, p, lenp);
1636     }
1637 
1638     uvchr_to_utf8(p, c);
1639     return CALL_LOWER_CASE(c, p, p, lenp);
1640 }
1641 
1642 UV
1643 Perl__to_fold_latin1(pTHX_ const U8 c, U8* p, STRLEN *lenp, const unsigned int flags)
1644 {
1645     /* Corresponds to to_lower_latin1(); <flags> bits meanings:
1646      *	    FOLD_FLAGS_NOMIX_ASCII iff non-ASCII to ASCII folds are prohibited
1647      *	    FOLD_FLAGS_FULL  iff full folding is to be used;
1648      *
1649      *	Not to be used for locale folds
1650      */
1651 
1652     UV converted;
1653 
1654     PERL_ARGS_ASSERT__TO_FOLD_LATIN1;
1655     PERL_UNUSED_CONTEXT;
1656 
1657     assert (! (flags & FOLD_FLAGS_LOCALE));
1658 
1659     if (UNLIKELY(c == MICRO_SIGN)) {
1660 	converted = GREEK_SMALL_LETTER_MU;
1661     }
1662 #if    UNICODE_MAJOR_VERSION > 3 /* no multifolds in early Unicode */   \
1663    || (UNICODE_MAJOR_VERSION == 3 && (   UNICODE_DOT_VERSION > 0)       \
1664                                       || UNICODE_DOT_DOT_VERSION > 0)
1665     else if (   (flags & FOLD_FLAGS_FULL)
1666              && UNLIKELY(c == LATIN_SMALL_LETTER_SHARP_S))
1667     {
1668         /* If can't cross 127/128 boundary, can't return "ss"; instead return
1669          * two U+017F characters, as fc("\df") should eq fc("\x{17f}\x{17f}")
1670          * under those circumstances. */
1671         if (flags & FOLD_FLAGS_NOMIX_ASCII) {
1672             *lenp = 2 * sizeof(LATIN_SMALL_LETTER_LONG_S_UTF8) - 2;
1673             Copy(LATIN_SMALL_LETTER_LONG_S_UTF8 LATIN_SMALL_LETTER_LONG_S_UTF8,
1674                  p, *lenp, U8);
1675             return LATIN_SMALL_LETTER_LONG_S;
1676         }
1677         else {
1678             *(p)++ = 's';
1679             *p = 's';
1680             *lenp = 2;
1681             return 's';
1682         }
1683     }
1684 #endif
1685     else { /* In this range the fold of all other characters is their lower
1686               case */
1687 	converted = toLOWER_LATIN1(c);
1688     }
1689 
1690     if (UVCHR_IS_INVARIANT(converted)) {
1691 	*p = (U8) converted;
1692 	*lenp = 1;
1693     }
1694     else {
1695 	*(p)++ = UTF8_TWO_BYTE_HI(converted);
1696 	*p = UTF8_TWO_BYTE_LO(converted);
1697 	*lenp = 2;
1698     }
1699 
1700     return converted;
1701 }
1702 
1703 UV
1704 Perl__to_uni_fold_flags(pTHX_ UV c, U8* p, STRLEN *lenp, U8 flags)
1705 {
1706 
1707     /* Not currently externally documented, and subject to change
1708      *  <flags> bits meanings:
1709      *	    FOLD_FLAGS_FULL  iff full folding is to be used;
1710      *	    FOLD_FLAGS_LOCALE is set iff the rules from the current underlying
1711      *	                      locale are to be used.
1712      *	    FOLD_FLAGS_NOMIX_ASCII iff non-ASCII to ASCII folds are prohibited
1713      */
1714 
1715     PERL_ARGS_ASSERT__TO_UNI_FOLD_FLAGS;
1716 
1717     if (flags & FOLD_FLAGS_LOCALE) {
1718         /* Treat a UTF-8 locale as not being in locale at all */
1719         if (IN_UTF8_CTYPE_LOCALE) {
1720             flags &= ~FOLD_FLAGS_LOCALE;
1721         }
1722         else {
1723             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
1724             goto needs_full_generality;
1725         }
1726     }
1727 
1728     if (c < 256) {
1729         return _to_fold_latin1((U8) c, p, lenp,
1730 			    flags & (FOLD_FLAGS_FULL | FOLD_FLAGS_NOMIX_ASCII));
1731     }
1732 
1733     /* Here, above 255.  If no special needs, just use the macro */
1734     if ( ! (flags & (FOLD_FLAGS_LOCALE|FOLD_FLAGS_NOMIX_ASCII))) {
1735 	uvchr_to_utf8(p, c);
1736 	return CALL_FOLD_CASE(c, p, p, lenp, flags & FOLD_FLAGS_FULL);
1737     }
1738     else {  /* Otherwise, _to_utf8_fold_flags has the intelligence to deal with
1739 	       the special flags. */
1740 	U8 utf8_c[UTF8_MAXBYTES + 1];
1741 
1742       needs_full_generality:
1743 	uvchr_to_utf8(utf8_c, c);
1744 	return _to_utf8_fold_flags(utf8_c, p, lenp, flags);
1745     }
1746 }
1747 
1748 PERL_STATIC_INLINE bool
1749 S_is_utf8_common(pTHX_ const U8 *const p, SV **swash,
1750 		 const char *const swashname, SV* const invlist)
1751 {
1752     /* returns a boolean giving whether or not the UTF8-encoded character that
1753      * starts at <p> is in the swash indicated by <swashname>.  <swash>
1754      * contains a pointer to where the swash indicated by <swashname>
1755      * is to be stored; which this routine will do, so that future calls will
1756      * look at <*swash> and only generate a swash if it is not null.  <invlist>
1757      * is NULL or an inversion list that defines the swash.  If not null, it
1758      * saves time during initialization of the swash.
1759      *
1760      * Note that it is assumed that the buffer length of <p> is enough to
1761      * contain all the bytes that comprise the character.  Thus, <*p> should
1762      * have been checked before this call for mal-formedness enough to assure
1763      * that. */
1764 
1765     PERL_ARGS_ASSERT_IS_UTF8_COMMON;
1766 
1767     /* The API should have included a length for the UTF-8 character in <p>,
1768      * but it doesn't.  We therefore assume that p has been validated at least
1769      * as far as there being enough bytes available in it to accommodate the
1770      * character without reading beyond the end, and pass that number on to the
1771      * validating routine */
1772     if (! isUTF8_CHAR(p, p + UTF8SKIP(p))) {
1773         if (ckWARN_d(WARN_UTF8)) {
1774             Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED,WARN_UTF8),
1775 		    "Passing malformed UTF-8 to \"%s\" is deprecated", swashname);
1776             if (ckWARN(WARN_UTF8)) {    /* This will output details as to the
1777                                            what the malformation is */
1778                 utf8_to_uvchr_buf(p, p + UTF8SKIP(p), NULL);
1779             }
1780         }
1781         return FALSE;
1782     }
1783     if (!*swash) {
1784         U8 flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
1785         *swash = _core_swash_init("utf8",
1786 
1787                                   /* Only use the name if there is no inversion
1788                                    * list; otherwise will go out to disk */
1789                                   (invlist) ? "" : swashname,
1790 
1791                                   &PL_sv_undef, 1, 0, invlist, &flags);
1792     }
1793 
1794     return swash_fetch(*swash, p, TRUE) != 0;
1795 }
1796 
1797 bool
1798 Perl__is_utf8_FOO(pTHX_ const U8 classnum, const U8 *p)
1799 {
1800     PERL_ARGS_ASSERT__IS_UTF8_FOO;
1801 
1802     assert(classnum < _FIRST_NON_SWASH_CC);
1803 
1804     return is_utf8_common(p,
1805                           &PL_utf8_swash_ptrs[classnum],
1806                           swash_property_names[classnum],
1807                           PL_XPosix_ptrs[classnum]);
1808 }
1809 
1810 bool
1811 Perl__is_utf8_perl_idstart(pTHX_ const U8 *p)
1812 {
1813     SV* invlist = NULL;
1814 
1815     PERL_ARGS_ASSERT__IS_UTF8_PERL_IDSTART;
1816 
1817     if (! PL_utf8_perl_idstart) {
1818         invlist = _new_invlist_C_array(_Perl_IDStart_invlist);
1819     }
1820     return is_utf8_common(p, &PL_utf8_perl_idstart, "_Perl_IDStart", invlist);
1821 }
1822 
1823 bool
1824 Perl__is_utf8_xidstart(pTHX_ const U8 *p)
1825 {
1826     PERL_ARGS_ASSERT__IS_UTF8_XIDSTART;
1827 
1828     if (*p == '_')
1829 	return TRUE;
1830     return is_utf8_common(p, &PL_utf8_xidstart, "XIdStart", NULL);
1831 }
1832 
1833 bool
1834 Perl__is_utf8_perl_idcont(pTHX_ const U8 *p)
1835 {
1836     SV* invlist = NULL;
1837 
1838     PERL_ARGS_ASSERT__IS_UTF8_PERL_IDCONT;
1839 
1840     if (! PL_utf8_perl_idcont) {
1841         invlist = _new_invlist_C_array(_Perl_IDCont_invlist);
1842     }
1843     return is_utf8_common(p, &PL_utf8_perl_idcont, "_Perl_IDCont", invlist);
1844 }
1845 
1846 bool
1847 Perl__is_utf8_idcont(pTHX_ const U8 *p)
1848 {
1849     PERL_ARGS_ASSERT__IS_UTF8_IDCONT;
1850 
1851     return is_utf8_common(p, &PL_utf8_idcont, "IdContinue", NULL);
1852 }
1853 
1854 bool
1855 Perl__is_utf8_xidcont(pTHX_ const U8 *p)
1856 {
1857     PERL_ARGS_ASSERT__IS_UTF8_XIDCONT;
1858 
1859     return is_utf8_common(p, &PL_utf8_idcont, "XIdContinue", NULL);
1860 }
1861 
1862 bool
1863 Perl__is_utf8_mark(pTHX_ const U8 *p)
1864 {
1865     PERL_ARGS_ASSERT__IS_UTF8_MARK;
1866 
1867     return is_utf8_common(p, &PL_utf8_mark, "IsM", NULL);
1868 }
1869 
1870 /*
1871 =for apidoc to_utf8_case
1872 
1873 Instead use the appropriate one of L</toUPPER_utf8>,
1874 L</toTITLE_utf8>,
1875 L</toLOWER_utf8>,
1876 or L</toFOLD_utf8>.
1877 
1878 C<p> contains the pointer to the UTF-8 string encoding
1879 the character that is being converted.  This routine assumes that the character
1880 at C<p> is well-formed.
1881 
1882 C<ustrp> is a pointer to the character buffer to put the
1883 conversion result to.  C<lenp> is a pointer to the length
1884 of the result.
1885 
1886 C<swashp> is a pointer to the swash to use.
1887 
1888 Both the special and normal mappings are stored in F<lib/unicore/To/Foo.pl>,
1889 and loaded by C<SWASHNEW>, using F<lib/utf8_heavy.pl>.  C<special> (usually,
1890 but not always, a multicharacter mapping), is tried first.
1891 
1892 C<special> is a string, normally C<NULL> or C<"">.  C<NULL> means to not use
1893 any special mappings; C<""> means to use the special mappings.  Values other
1894 than these two are treated as the name of the hash containing the special
1895 mappings, like C<"utf8::ToSpecLower">.
1896 
1897 C<normal> is a string like C<"ToLower"> which means the swash
1898 C<%utf8::ToLower>.
1899 
1900 Code points above the platform's C<IV_MAX> will raise a deprecation warning,
1901 unless those are turned off.
1902 
1903 =cut */
1904 
1905 UV
1906 Perl_to_utf8_case(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp,
1907 			SV **swashp, const char *normal, const char *special)
1908 {
1909     PERL_ARGS_ASSERT_TO_UTF8_CASE;
1910 
1911     return _to_utf8_case(valid_utf8_to_uvchr(p, NULL), p, ustrp, lenp, swashp, normal, special);
1912 }
1913 
1914     /* change namve uv1 to 'from' */
1915 STATIC UV
1916 S__to_utf8_case(pTHX_ const UV uv1, const U8 *p, U8* ustrp, STRLEN *lenp,
1917 		SV **swashp, const char *normal, const char *special)
1918 {
1919     STRLEN len = 0;
1920 
1921     PERL_ARGS_ASSERT__TO_UTF8_CASE;
1922 
1923     /* For code points that don't change case, we already know that the output
1924      * of this function is the unchanged input, so we can skip doing look-ups
1925      * for them.  Unfortunately the case-changing code points are scattered
1926      * around.  But there are some long consecutive ranges where there are no
1927      * case changing code points.  By adding tests, we can eliminate the lookup
1928      * for all the ones in such ranges.  This is currently done here only for
1929      * just a few cases where the scripts are in common use in modern commerce
1930      * (and scripts adjacent to those which can be included without additional
1931      * tests). */
1932 
1933     if (uv1 >= 0x0590) {
1934         /* This keeps from needing further processing the code points most
1935          * likely to be used in the following non-cased scripts: Hebrew,
1936          * Arabic, Syriac, Thaana, NKo, Samaritan, Mandaic, Devanagari,
1937          * Bengali, Gurmukhi, Gujarati, Oriya, Tamil, Telugu, Kannada,
1938          * Malayalam, Sinhala, Thai, Lao, Tibetan, Myanmar */
1939         if (uv1 < 0x10A0) {
1940             goto cases_to_self;
1941         }
1942 
1943         /* The following largish code point ranges also don't have case
1944          * changes, but khw didn't think they warranted extra tests to speed
1945          * them up (which would slightly slow down everything else above them):
1946          * 1100..139F   Hangul Jamo, Ethiopic
1947          * 1400..1CFF   Unified Canadian Aboriginal Syllabics, Ogham, Runic,
1948          *              Tagalog, Hanunoo, Buhid, Tagbanwa, Khmer, Mongolian,
1949          *              Limbu, Tai Le, New Tai Lue, Buginese, Tai Tham,
1950          *              Combining Diacritical Marks Extended, Balinese,
1951          *              Sundanese, Batak, Lepcha, Ol Chiki
1952          * 2000..206F   General Punctuation
1953          */
1954 
1955         if (uv1 >= 0x2D30) {
1956 
1957             /* This keeps the from needing further processing the code points
1958              * most likely to be used in the following non-cased major scripts:
1959              * CJK, Katakana, Hiragana, plus some less-likely scripts.
1960              *
1961              * (0x2D30 above might have to be changed to 2F00 in the unlikely
1962              * event that Unicode eventually allocates the unused block as of
1963              * v8.0 2FE0..2FEF to code points that are cased.  khw has verified
1964              * that the test suite will start having failures to alert you
1965              * should that happen) */
1966             if (uv1 < 0xA640) {
1967                 goto cases_to_self;
1968             }
1969 
1970             if (uv1 >= 0xAC00) {
1971                 if (UNLIKELY(UNICODE_IS_SURROGATE(uv1))) {
1972                     if (ckWARN_d(WARN_SURROGATE)) {
1973                         const char* desc = (PL_op) ? OP_DESC(PL_op) : normal;
1974                         Perl_warner(aTHX_ packWARN(WARN_SURROGATE),
1975                             "Operation \"%s\" returns its argument for UTF-16 surrogate U+%04"UVXf"", desc, uv1);
1976                     }
1977                     goto cases_to_self;
1978                 }
1979 
1980                 /* AC00..FAFF Catches Hangul syllables and private use, plus
1981                  * some others */
1982                 if (uv1 < 0xFB00) {
1983                     goto cases_to_self;
1984 
1985                 }
1986 
1987                 if (UNLIKELY(UNICODE_IS_SUPER(uv1))) {
1988                     if (   UNLIKELY(uv1 > MAX_NON_DEPRECATED_CP)
1989                         && ckWARN_d(WARN_DEPRECATED))
1990                     {
1991                         Perl_warner(aTHX_ packWARN(WARN_DEPRECATED),
1992                                 cp_above_legal_max, uv1, MAX_NON_DEPRECATED_CP);
1993                     }
1994                     if (ckWARN_d(WARN_NON_UNICODE)) {
1995                         const char* desc = (PL_op) ? OP_DESC(PL_op) : normal;
1996                         Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
1997                             "Operation \"%s\" returns its argument for non-Unicode code point 0x%04"UVXf"", desc, uv1);
1998                     }
1999                     goto cases_to_self;
2000                 }
2001 #ifdef HIGHEST_CASE_CHANGING_CP_FOR_USE_ONLY_BY_UTF8_DOT_C
2002                 if (UNLIKELY(uv1
2003                     > HIGHEST_CASE_CHANGING_CP_FOR_USE_ONLY_BY_UTF8_DOT_C))
2004                 {
2005 
2006                     /* As of this writing, this means we avoid swash creation
2007                      * for anything beyond low Plane 1 */
2008                     goto cases_to_self;
2009                 }
2010 #endif
2011             }
2012         }
2013 
2014 	/* Note that non-characters are perfectly legal, so no warning should
2015          * be given.  There are so few of them, that it isn't worth the extra
2016          * tests to avoid swash creation */
2017     }
2018 
2019     if (!*swashp) /* load on-demand */
2020          *swashp = _core_swash_init("utf8", normal, &PL_sv_undef, 4, 0, NULL, NULL);
2021 
2022     if (special) {
2023          /* It might be "special" (sometimes, but not always,
2024 	  * a multicharacter mapping) */
2025          HV *hv = NULL;
2026 	 SV **svp;
2027 
2028 	 /* If passed in the specials name, use that; otherwise use any
2029 	  * given in the swash */
2030          if (*special != '\0') {
2031             hv = get_hv(special, 0);
2032         }
2033         else {
2034             svp = hv_fetchs(MUTABLE_HV(SvRV(*swashp)), "SPECIALS", 0);
2035             if (svp) {
2036                 hv = MUTABLE_HV(SvRV(*svp));
2037             }
2038         }
2039 
2040 	 if (hv
2041              && (svp = hv_fetch(hv, (const char*)p, UVCHR_SKIP(uv1), FALSE))
2042              && (*svp))
2043          {
2044 	     const char *s;
2045 
2046 	      s = SvPV_const(*svp, len);
2047 	      if (len == 1)
2048                   /* EIGHTBIT */
2049 		   len = uvchr_to_utf8(ustrp, *(U8*)s) - ustrp;
2050 	      else {
2051 		   Copy(s, ustrp, len, U8);
2052 	      }
2053 	 }
2054     }
2055 
2056     if (!len && *swashp) {
2057 	const UV uv2 = swash_fetch(*swashp, p, TRUE /* => is UTF-8 */);
2058 
2059 	 if (uv2) {
2060 	      /* It was "normal" (a single character mapping). */
2061 	      len = uvchr_to_utf8(ustrp, uv2) - ustrp;
2062 	 }
2063     }
2064 
2065     if (len) {
2066         if (lenp) {
2067             *lenp = len;
2068         }
2069         return valid_utf8_to_uvchr(ustrp, 0);
2070     }
2071 
2072     /* Here, there was no mapping defined, which means that the code point maps
2073      * to itself.  Return the inputs */
2074   cases_to_self:
2075     len = UTF8SKIP(p);
2076     if (p != ustrp) {   /* Don't copy onto itself */
2077         Copy(p, ustrp, len, U8);
2078     }
2079 
2080     if (lenp)
2081 	 *lenp = len;
2082 
2083     return uv1;
2084 
2085 }
2086 
2087 STATIC UV
2088 S_check_locale_boundary_crossing(pTHX_ const U8* const p, const UV result, U8* const ustrp, STRLEN *lenp)
2089 {
2090     /* This is called when changing the case of a UTF-8-encoded character above
2091      * the Latin1 range, and the operation is in a non-UTF-8 locale.  If the
2092      * result contains a character that crosses the 255/256 boundary, disallow
2093      * the change, and return the original code point.  See L<perlfunc/lc> for
2094      * why;
2095      *
2096      * p	points to the original string whose case was changed; assumed
2097      *          by this routine to be well-formed
2098      * result	the code point of the first character in the changed-case string
2099      * ustrp	points to the changed-case string (<result> represents its first char)
2100      * lenp	points to the length of <ustrp> */
2101 
2102     UV original;    /* To store the first code point of <p> */
2103 
2104     PERL_ARGS_ASSERT_CHECK_LOCALE_BOUNDARY_CROSSING;
2105 
2106     assert(UTF8_IS_ABOVE_LATIN1(*p));
2107 
2108     /* We know immediately if the first character in the string crosses the
2109      * boundary, so can skip */
2110     if (result > 255) {
2111 
2112 	/* Look at every character in the result; if any cross the
2113 	* boundary, the whole thing is disallowed */
2114 	U8* s = ustrp + UTF8SKIP(ustrp);
2115 	U8* e = ustrp + *lenp;
2116 	while (s < e) {
2117 	    if (! UTF8_IS_ABOVE_LATIN1(*s)) {
2118 		goto bad_crossing;
2119 	    }
2120 	    s += UTF8SKIP(s);
2121 	}
2122 
2123         /* Here, no characters crossed, result is ok as-is, but we warn. */
2124         _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(p, p + UTF8SKIP(p));
2125 	return result;
2126     }
2127 
2128   bad_crossing:
2129 
2130     /* Failed, have to return the original */
2131     original = valid_utf8_to_uvchr(p, lenp);
2132 
2133     /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
2134     Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2135                            "Can't do %s(\"\\x{%"UVXf"}\") on non-UTF-8 locale; "
2136                            "resolved to \"\\x{%"UVXf"}\".",
2137                            OP_DESC(PL_op),
2138                            original,
2139                            original);
2140     Copy(p, ustrp, *lenp, char);
2141     return original;
2142 }
2143 
2144 /*
2145 =for apidoc to_utf8_upper
2146 
2147 Instead use L</toUPPER_utf8>.
2148 
2149 =cut */
2150 
2151 /* Not currently externally documented, and subject to change:
2152  * <flags> is set iff iff the rules from the current underlying locale are to
2153  *         be used. */
2154 
2155 UV
2156 Perl__to_utf8_upper_flags(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp, bool flags)
2157 {
2158     UV result;
2159 
2160     PERL_ARGS_ASSERT__TO_UTF8_UPPER_FLAGS;
2161 
2162     if (flags) {
2163         /* Treat a UTF-8 locale as not being in locale at all */
2164         if (IN_UTF8_CTYPE_LOCALE) {
2165             flags = FALSE;
2166         }
2167         else {
2168             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2169         }
2170     }
2171 
2172     if (UTF8_IS_INVARIANT(*p)) {
2173 	if (flags) {
2174 	    result = toUPPER_LC(*p);
2175 	}
2176 	else {
2177 	    return _to_upper_title_latin1(*p, ustrp, lenp, 'S');
2178 	}
2179     }
2180     else if UTF8_IS_DOWNGRADEABLE_START(*p) {
2181 	if (flags) {
2182             U8 c = EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1));
2183 	    result = toUPPER_LC(c);
2184 	}
2185 	else {
2186 	    return _to_upper_title_latin1(EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1)),
2187 				          ustrp, lenp, 'S');
2188 	}
2189     }
2190     else {  /* UTF-8, ord above 255 */
2191 	result = CALL_UPPER_CASE(valid_utf8_to_uvchr(p, NULL), p, ustrp, lenp);
2192 
2193 	if (flags) {
2194 	    result = check_locale_boundary_crossing(p, result, ustrp, lenp);
2195 	}
2196 	return result;
2197     }
2198 
2199     /* Here, used locale rules.  Convert back to UTF-8 */
2200     if (UTF8_IS_INVARIANT(result)) {
2201 	*ustrp = (U8) result;
2202 	*lenp = 1;
2203     }
2204     else {
2205 	*ustrp = UTF8_EIGHT_BIT_HI((U8) result);
2206 	*(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);
2207 	*lenp = 2;
2208     }
2209 
2210     return result;
2211 }
2212 
2213 /*
2214 =for apidoc to_utf8_title
2215 
2216 Instead use L</toTITLE_utf8>.
2217 
2218 =cut */
2219 
2220 /* Not currently externally documented, and subject to change:
2221  * <flags> is set iff the rules from the current underlying locale are to be
2222  *         used.  Since titlecase is not defined in POSIX, for other than a
2223  *         UTF-8 locale, uppercase is used instead for code points < 256.
2224  */
2225 
2226 UV
2227 Perl__to_utf8_title_flags(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp, bool flags)
2228 {
2229     UV result;
2230 
2231     PERL_ARGS_ASSERT__TO_UTF8_TITLE_FLAGS;
2232 
2233     if (flags) {
2234         /* Treat a UTF-8 locale as not being in locale at all */
2235         if (IN_UTF8_CTYPE_LOCALE) {
2236             flags = FALSE;
2237         }
2238         else {
2239             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2240         }
2241     }
2242 
2243     if (UTF8_IS_INVARIANT(*p)) {
2244 	if (flags) {
2245 	    result = toUPPER_LC(*p);
2246 	}
2247 	else {
2248 	    return _to_upper_title_latin1(*p, ustrp, lenp, 's');
2249 	}
2250     }
2251     else if UTF8_IS_DOWNGRADEABLE_START(*p) {
2252 	if (flags) {
2253             U8 c = EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1));
2254 	    result = toUPPER_LC(c);
2255 	}
2256 	else {
2257 	    return _to_upper_title_latin1(EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1)),
2258 				          ustrp, lenp, 's');
2259 	}
2260     }
2261     else {  /* UTF-8, ord above 255 */
2262 	result = CALL_TITLE_CASE(valid_utf8_to_uvchr(p, NULL), p, ustrp, lenp);
2263 
2264 	if (flags) {
2265 	    result = check_locale_boundary_crossing(p, result, ustrp, lenp);
2266 	}
2267 	return result;
2268     }
2269 
2270     /* Here, used locale rules.  Convert back to UTF-8 */
2271     if (UTF8_IS_INVARIANT(result)) {
2272 	*ustrp = (U8) result;
2273 	*lenp = 1;
2274     }
2275     else {
2276 	*ustrp = UTF8_EIGHT_BIT_HI((U8) result);
2277 	*(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);
2278 	*lenp = 2;
2279     }
2280 
2281     return result;
2282 }
2283 
2284 /*
2285 =for apidoc to_utf8_lower
2286 
2287 Instead use L</toLOWER_utf8>.
2288 
2289 =cut */
2290 
2291 /* Not currently externally documented, and subject to change:
2292  * <flags> is set iff iff the rules from the current underlying locale are to
2293  *         be used.
2294  */
2295 
2296 UV
2297 Perl__to_utf8_lower_flags(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp, bool flags)
2298 {
2299     UV result;
2300 
2301     PERL_ARGS_ASSERT__TO_UTF8_LOWER_FLAGS;
2302 
2303     if (flags) {
2304         /* Treat a UTF-8 locale as not being in locale at all */
2305         if (IN_UTF8_CTYPE_LOCALE) {
2306             flags = FALSE;
2307         }
2308         else {
2309             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2310         }
2311     }
2312 
2313     if (UTF8_IS_INVARIANT(*p)) {
2314 	if (flags) {
2315 	    result = toLOWER_LC(*p);
2316 	}
2317 	else {
2318 	    return to_lower_latin1(*p, ustrp, lenp);
2319 	}
2320     }
2321     else if UTF8_IS_DOWNGRADEABLE_START(*p) {
2322 	if (flags) {
2323             U8 c = EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1));
2324 	    result = toLOWER_LC(c);
2325 	}
2326 	else {
2327 	    return to_lower_latin1(EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1)),
2328 		                   ustrp, lenp);
2329 	}
2330     }
2331     else {  /* UTF-8, ord above 255 */
2332 	result = CALL_LOWER_CASE(valid_utf8_to_uvchr(p, NULL), p, ustrp, lenp);
2333 
2334 	if (flags) {
2335 	    result = check_locale_boundary_crossing(p, result, ustrp, lenp);
2336 	}
2337 
2338 	return result;
2339     }
2340 
2341     /* Here, used locale rules.  Convert back to UTF-8 */
2342     if (UTF8_IS_INVARIANT(result)) {
2343 	*ustrp = (U8) result;
2344 	*lenp = 1;
2345     }
2346     else {
2347 	*ustrp = UTF8_EIGHT_BIT_HI((U8) result);
2348 	*(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);
2349 	*lenp = 2;
2350     }
2351 
2352     return result;
2353 }
2354 
2355 /*
2356 =for apidoc to_utf8_fold
2357 
2358 Instead use L</toFOLD_utf8>.
2359 
2360 =cut */
2361 
2362 /* Not currently externally documented, and subject to change,
2363  * in <flags>
2364  *	bit FOLD_FLAGS_LOCALE is set iff the rules from the current underlying
2365  *	                      locale are to be used.
2366  *      bit FOLD_FLAGS_FULL   is set iff full case folds are to be used;
2367  *			      otherwise simple folds
2368  *      bit FOLD_FLAGS_NOMIX_ASCII is set iff folds of non-ASCII to ASCII are
2369  *			      prohibited
2370  */
2371 
2372 UV
2373 Perl__to_utf8_fold_flags(pTHX_ const U8 *p, U8* ustrp, STRLEN *lenp, U8 flags)
2374 {
2375     UV result;
2376 
2377     PERL_ARGS_ASSERT__TO_UTF8_FOLD_FLAGS;
2378 
2379     /* These are mutually exclusive */
2380     assert (! ((flags & FOLD_FLAGS_LOCALE) && (flags & FOLD_FLAGS_NOMIX_ASCII)));
2381 
2382     assert(p != ustrp); /* Otherwise overwrites */
2383 
2384     if (flags & FOLD_FLAGS_LOCALE) {
2385         /* Treat a UTF-8 locale as not being in locale at all */
2386         if (IN_UTF8_CTYPE_LOCALE) {
2387             flags &= ~FOLD_FLAGS_LOCALE;
2388         }
2389         else {
2390             _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
2391         }
2392     }
2393 
2394     if (UTF8_IS_INVARIANT(*p)) {
2395 	if (flags & FOLD_FLAGS_LOCALE) {
2396 	    result = toFOLD_LC(*p);
2397 	}
2398 	else {
2399 	    return _to_fold_latin1(*p, ustrp, lenp,
2400                             flags & (FOLD_FLAGS_FULL | FOLD_FLAGS_NOMIX_ASCII));
2401 	}
2402     }
2403     else if UTF8_IS_DOWNGRADEABLE_START(*p) {
2404 	if (flags & FOLD_FLAGS_LOCALE) {
2405             U8 c = EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1));
2406 	    result = toFOLD_LC(c);
2407 	}
2408 	else {
2409 	    return _to_fold_latin1(EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1)),
2410                             ustrp, lenp,
2411                             flags & (FOLD_FLAGS_FULL | FOLD_FLAGS_NOMIX_ASCII));
2412 	}
2413     }
2414     else {  /* UTF-8, ord above 255 */
2415 	result = CALL_FOLD_CASE(valid_utf8_to_uvchr(p, NULL), p, ustrp, lenp, flags & FOLD_FLAGS_FULL);
2416 
2417 	if (flags & FOLD_FLAGS_LOCALE) {
2418 
2419 #           define LONG_S_T      LATIN_SMALL_LIGATURE_LONG_S_T_UTF8
2420             const unsigned int long_s_t_len    = sizeof(LONG_S_T) - 1;
2421 
2422 #         ifdef LATIN_CAPITAL_LETTER_SHARP_S_UTF8
2423 #           define CAP_SHARP_S   LATIN_CAPITAL_LETTER_SHARP_S_UTF8
2424 
2425             const unsigned int cap_sharp_s_len = sizeof(CAP_SHARP_S) - 1;
2426 
2427             /* Special case these two characters, as what normally gets
2428              * returned under locale doesn't work */
2429             if (UTF8SKIP(p) == cap_sharp_s_len
2430                 && memEQ((char *) p, CAP_SHARP_S, cap_sharp_s_len))
2431             {
2432                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
2433                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2434                               "Can't do fc(\"\\x{1E9E}\") on non-UTF-8 locale; "
2435                               "resolved to \"\\x{17F}\\x{17F}\".");
2436                 goto return_long_s;
2437             }
2438             else
2439 #endif
2440                  if (UTF8SKIP(p) == long_s_t_len
2441                      && memEQ((char *) p, LONG_S_T, long_s_t_len))
2442             {
2443                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
2444                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2445                               "Can't do fc(\"\\x{FB05}\") on non-UTF-8 locale; "
2446                               "resolved to \"\\x{FB06}\".");
2447                 goto return_ligature_st;
2448             }
2449 
2450 #if    UNICODE_MAJOR_VERSION   == 3         \
2451     && UNICODE_DOT_VERSION     == 0         \
2452     && UNICODE_DOT_DOT_VERSION == 1
2453 #           define DOTTED_I   LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE_UTF8
2454 
2455             /* And special case this on this Unicode version only, for the same
2456              * reaons the other two are special cased.  They would cross the
2457              * 255/256 boundary which is forbidden under /l, and so the code
2458              * wouldn't catch that they are equivalent (which they are only in
2459              * this release) */
2460             else if (UTF8SKIP(p) == sizeof(DOTTED_I) - 1
2461                      && memEQ((char *) p, DOTTED_I, sizeof(DOTTED_I) - 1))
2462             {
2463                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
2464                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
2465                               "Can't do fc(\"\\x{0130}\") on non-UTF-8 locale; "
2466                               "resolved to \"\\x{0131}\".");
2467                 goto return_dotless_i;
2468             }
2469 #endif
2470 
2471 	    return check_locale_boundary_crossing(p, result, ustrp, lenp);
2472 	}
2473 	else if (! (flags & FOLD_FLAGS_NOMIX_ASCII)) {
2474 	    return result;
2475 	}
2476 	else {
2477 	    /* This is called when changing the case of a UTF-8-encoded
2478              * character above the ASCII range, and the result should not
2479              * contain an ASCII character. */
2480 
2481 	    UV original;    /* To store the first code point of <p> */
2482 
2483 	    /* Look at every character in the result; if any cross the
2484 	    * boundary, the whole thing is disallowed */
2485 	    U8* s = ustrp;
2486 	    U8* e = ustrp + *lenp;
2487 	    while (s < e) {
2488 		if (isASCII(*s)) {
2489 		    /* Crossed, have to return the original */
2490 		    original = valid_utf8_to_uvchr(p, lenp);
2491 
2492                     /* But in these instances, there is an alternative we can
2493                      * return that is valid */
2494                     if (original == LATIN_SMALL_LETTER_SHARP_S
2495 #ifdef LATIN_CAPITAL_LETTER_SHARP_S /* not defined in early Unicode releases */
2496                         || original == LATIN_CAPITAL_LETTER_SHARP_S
2497 #endif
2498                     ) {
2499                         goto return_long_s;
2500                     }
2501                     else if (original == LATIN_SMALL_LIGATURE_LONG_S_T) {
2502                         goto return_ligature_st;
2503                     }
2504 #if    UNICODE_MAJOR_VERSION   == 3         \
2505     && UNICODE_DOT_VERSION     == 0         \
2506     && UNICODE_DOT_DOT_VERSION == 1
2507 
2508                     else if (original == LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE) {
2509                         goto return_dotless_i;
2510                     }
2511 #endif
2512 		    Copy(p, ustrp, *lenp, char);
2513 		    return original;
2514 		}
2515 		s += UTF8SKIP(s);
2516 	    }
2517 
2518 	    /* Here, no characters crossed, result is ok as-is */
2519 	    return result;
2520 	}
2521     }
2522 
2523     /* Here, used locale rules.  Convert back to UTF-8 */
2524     if (UTF8_IS_INVARIANT(result)) {
2525 	*ustrp = (U8) result;
2526 	*lenp = 1;
2527     }
2528     else {
2529 	*ustrp = UTF8_EIGHT_BIT_HI((U8) result);
2530 	*(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);
2531 	*lenp = 2;
2532     }
2533 
2534     return result;
2535 
2536   return_long_s:
2537     /* Certain folds to 'ss' are prohibited by the options, but they do allow
2538      * folds to a string of two of these characters.  By returning this
2539      * instead, then, e.g.,
2540      *      fc("\x{1E9E}") eq fc("\x{17F}\x{17F}")
2541      * works. */
2542 
2543     *lenp = 2 * sizeof(LATIN_SMALL_LETTER_LONG_S_UTF8) - 2;
2544     Copy(LATIN_SMALL_LETTER_LONG_S_UTF8 LATIN_SMALL_LETTER_LONG_S_UTF8,
2545         ustrp, *lenp, U8);
2546     return LATIN_SMALL_LETTER_LONG_S;
2547 
2548   return_ligature_st:
2549     /* Two folds to 'st' are prohibited by the options; instead we pick one and
2550      * have the other one fold to it */
2551 
2552     *lenp = sizeof(LATIN_SMALL_LIGATURE_ST_UTF8) - 1;
2553     Copy(LATIN_SMALL_LIGATURE_ST_UTF8, ustrp, *lenp, U8);
2554     return LATIN_SMALL_LIGATURE_ST;
2555 
2556 #if    UNICODE_MAJOR_VERSION   == 3         \
2557     && UNICODE_DOT_VERSION     == 0         \
2558     && UNICODE_DOT_DOT_VERSION == 1
2559 
2560   return_dotless_i:
2561     *lenp = sizeof(LATIN_SMALL_LETTER_DOTLESS_I_UTF8) - 1;
2562     Copy(LATIN_SMALL_LETTER_DOTLESS_I_UTF8, ustrp, *lenp, U8);
2563     return LATIN_SMALL_LETTER_DOTLESS_I;
2564 
2565 #endif
2566 
2567 }
2568 
2569 /* Note:
2570  * Returns a "swash" which is a hash described in utf8.c:Perl_swash_fetch().
2571  * C<pkg> is a pointer to a package name for SWASHNEW, should be "utf8".
2572  * For other parameters, see utf8::SWASHNEW in lib/utf8_heavy.pl.
2573  */
2574 
2575 SV*
2576 Perl_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv, I32 minbits, I32 none)
2577 {
2578     PERL_ARGS_ASSERT_SWASH_INIT;
2579 
2580     /* Returns a copy of a swash initiated by the called function.  This is the
2581      * public interface, and returning a copy prevents others from doing
2582      * mischief on the original */
2583 
2584     return newSVsv(_core_swash_init(pkg, name, listsv, minbits, none, NULL, NULL));
2585 }
2586 
2587 SV*
2588 Perl__core_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv, I32 minbits, I32 none, SV* invlist, U8* const flags_p)
2589 {
2590 
2591     /*NOTE NOTE NOTE - If you want to use "return" in this routine you MUST
2592      * use the following define */
2593 
2594 #define CORE_SWASH_INIT_RETURN(x)   \
2595     PL_curpm= old_PL_curpm;         \
2596     return x
2597 
2598     /* Initialize and return a swash, creating it if necessary.  It does this
2599      * by calling utf8_heavy.pl in the general case.  The returned value may be
2600      * the swash's inversion list instead if the input parameters allow it.
2601      * Which is returned should be immaterial to callers, as the only
2602      * operations permitted on a swash, swash_fetch(), _get_swash_invlist(),
2603      * and swash_to_invlist() handle both these transparently.
2604      *
2605      * This interface should only be used by functions that won't destroy or
2606      * adversely change the swash, as doing so affects all other uses of the
2607      * swash in the program; the general public should use 'Perl_swash_init'
2608      * instead.
2609      *
2610      * pkg  is the name of the package that <name> should be in.
2611      * name is the name of the swash to find.  Typically it is a Unicode
2612      *	    property name, including user-defined ones
2613      * listsv is a string to initialize the swash with.  It must be of the form
2614      *	    documented as the subroutine return value in
2615      *	    L<perlunicode/User-Defined Character Properties>
2616      * minbits is the number of bits required to represent each data element.
2617      *	    It is '1' for binary properties.
2618      * none I (khw) do not understand this one, but it is used only in tr///.
2619      * invlist is an inversion list to initialize the swash with (or NULL)
2620      * flags_p if non-NULL is the address of various input and output flag bits
2621      *      to the routine, as follows:  ('I' means is input to the routine;
2622      *      'O' means output from the routine.  Only flags marked O are
2623      *      meaningful on return.)
2624      *  _CORE_SWASH_INIT_USER_DEFINED_PROPERTY indicates if the swash
2625      *      came from a user-defined property.  (I O)
2626      *  _CORE_SWASH_INIT_RETURN_IF_UNDEF indicates that instead of croaking
2627      *      when the swash cannot be located, to simply return NULL. (I)
2628      *  _CORE_SWASH_INIT_ACCEPT_INVLIST indicates that the caller will accept a
2629      *      return of an inversion list instead of a swash hash if this routine
2630      *      thinks that would result in faster execution of swash_fetch() later
2631      *      on. (I)
2632      *
2633      * Thus there are three possible inputs to find the swash: <name>,
2634      * <listsv>, and <invlist>.  At least one must be specified.  The result
2635      * will be the union of the specified ones, although <listsv>'s various
2636      * actions can intersect, etc. what <name> gives.  To avoid going out to
2637      * disk at all, <invlist> should specify completely what the swash should
2638      * have, and <listsv> should be &PL_sv_undef and <name> should be "".
2639      *
2640      * <invlist> is only valid for binary properties */
2641 
2642     PMOP *old_PL_curpm= PL_curpm; /* save away the old PL_curpm */
2643 
2644     SV* retval = &PL_sv_undef;
2645     HV* swash_hv = NULL;
2646     const int invlist_swash_boundary =
2647         (flags_p && *flags_p & _CORE_SWASH_INIT_ACCEPT_INVLIST)
2648         ? 512    /* Based on some benchmarking, but not extensive, see commit
2649                     message */
2650         : -1;   /* Never return just an inversion list */
2651 
2652     assert(listsv != &PL_sv_undef || strNE(name, "") || invlist);
2653     assert(! invlist || minbits == 1);
2654 
2655     PL_curpm= NULL; /* reset PL_curpm so that we dont get confused between the regex
2656                        that triggered the swash init and the swash init perl logic itself.
2657                        See perl #122747 */
2658 
2659     /* If data was passed in to go out to utf8_heavy to find the swash of, do
2660      * so */
2661     if (listsv != &PL_sv_undef || strNE(name, "")) {
2662 	dSP;
2663 	const size_t pkg_len = strlen(pkg);
2664 	const size_t name_len = strlen(name);
2665 	HV * const stash = gv_stashpvn(pkg, pkg_len, 0);
2666 	SV* errsv_save;
2667 	GV *method;
2668 
2669 	PERL_ARGS_ASSERT__CORE_SWASH_INIT;
2670 
2671 	PUSHSTACKi(PERLSI_MAGIC);
2672 	ENTER;
2673 	SAVEHINTS();
2674 	save_re_context();
2675 	/* We might get here via a subroutine signature which uses a utf8
2676 	 * parameter name, at which point PL_subname will have been set
2677 	 * but not yet used. */
2678 	save_item(PL_subname);
2679 	if (PL_parser && PL_parser->error_count)
2680 	    SAVEI8(PL_parser->error_count), PL_parser->error_count = 0;
2681 	method = gv_fetchmeth(stash, "SWASHNEW", 8, -1);
2682 	if (!method) {	/* demand load UTF-8 */
2683 	    ENTER;
2684 	    if ((errsv_save = GvSV(PL_errgv))) SAVEFREESV(errsv_save);
2685 	    GvSV(PL_errgv) = NULL;
2686 #ifndef NO_TAINT_SUPPORT
2687 	    /* It is assumed that callers of this routine are not passing in
2688 	     * any user derived data.  */
2689 	    /* Need to do this after save_re_context() as it will set
2690 	     * PL_tainted to 1 while saving $1 etc (see the code after getrx:
2691 	     * in Perl_magic_get).  Even line to create errsv_save can turn on
2692 	     * PL_tainted.  */
2693 	    SAVEBOOL(TAINT_get);
2694 	    TAINT_NOT;
2695 #endif
2696 	    Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT, newSVpvn(pkg,pkg_len),
2697 			     NULL);
2698 	    {
2699 		/* Not ERRSV, as there is no need to vivify a scalar we are
2700 		   about to discard. */
2701 		SV * const errsv = GvSV(PL_errgv);
2702 		if (!SvTRUE(errsv)) {
2703 		    GvSV(PL_errgv) = SvREFCNT_inc_simple(errsv_save);
2704 		    SvREFCNT_dec(errsv);
2705 		}
2706 	    }
2707 	    LEAVE;
2708 	}
2709 	SPAGAIN;
2710 	PUSHMARK(SP);
2711 	EXTEND(SP,5);
2712 	mPUSHp(pkg, pkg_len);
2713 	mPUSHp(name, name_len);
2714 	PUSHs(listsv);
2715 	mPUSHi(minbits);
2716 	mPUSHi(none);
2717 	PUTBACK;
2718 	if ((errsv_save = GvSV(PL_errgv))) SAVEFREESV(errsv_save);
2719 	GvSV(PL_errgv) = NULL;
2720 	/* If we already have a pointer to the method, no need to use
2721 	 * call_method() to repeat the lookup.  */
2722 	if (method
2723             ? call_sv(MUTABLE_SV(method), G_SCALAR)
2724 	    : call_sv(newSVpvs_flags("SWASHNEW", SVs_TEMP), G_SCALAR | G_METHOD))
2725 	{
2726 	    retval = *PL_stack_sp--;
2727 	    SvREFCNT_inc(retval);
2728 	}
2729 	{
2730 	    /* Not ERRSV.  See above. */
2731 	    SV * const errsv = GvSV(PL_errgv);
2732 	    if (!SvTRUE(errsv)) {
2733 		GvSV(PL_errgv) = SvREFCNT_inc_simple(errsv_save);
2734 		SvREFCNT_dec(errsv);
2735 	    }
2736 	}
2737 	LEAVE;
2738 	POPSTACK;
2739 	if (IN_PERL_COMPILETIME) {
2740 	    CopHINTS_set(PL_curcop, PL_hints);
2741 	}
2742 	if (!SvROK(retval) || SvTYPE(SvRV(retval)) != SVt_PVHV) {
2743 	    if (SvPOK(retval)) {
2744 
2745 		/* If caller wants to handle missing properties, let them */
2746 		if (flags_p && *flags_p & _CORE_SWASH_INIT_RETURN_IF_UNDEF) {
2747                     CORE_SWASH_INIT_RETURN(NULL);
2748 		}
2749 		Perl_croak(aTHX_
2750 			   "Can't find Unicode property definition \"%"SVf"\"",
2751 			   SVfARG(retval));
2752                 NOT_REACHED; /* NOTREACHED */
2753             }
2754 	}
2755     } /* End of calling the module to find the swash */
2756 
2757     /* If this operation fetched a swash, and we will need it later, get it */
2758     if (retval != &PL_sv_undef
2759         && (minbits == 1 || (flags_p
2760                             && ! (*flags_p
2761                                   & _CORE_SWASH_INIT_USER_DEFINED_PROPERTY))))
2762     {
2763         swash_hv = MUTABLE_HV(SvRV(retval));
2764 
2765         /* If we don't already know that there is a user-defined component to
2766          * this swash, and the user has indicated they wish to know if there is
2767          * one (by passing <flags_p>), find out */
2768         if (flags_p && ! (*flags_p & _CORE_SWASH_INIT_USER_DEFINED_PROPERTY)) {
2769             SV** user_defined = hv_fetchs(swash_hv, "USER_DEFINED", FALSE);
2770             if (user_defined && SvUV(*user_defined)) {
2771                 *flags_p |= _CORE_SWASH_INIT_USER_DEFINED_PROPERTY;
2772             }
2773         }
2774     }
2775 
2776     /* Make sure there is an inversion list for binary properties */
2777     if (minbits == 1) {
2778 	SV** swash_invlistsvp = NULL;
2779 	SV* swash_invlist = NULL;
2780 	bool invlist_in_swash_is_valid = FALSE;
2781 	bool swash_invlist_unclaimed = FALSE; /* whether swash_invlist has
2782 					    an unclaimed reference count */
2783 
2784         /* If this operation fetched a swash, get its already existing
2785          * inversion list, or create one for it */
2786 
2787         if (swash_hv) {
2788 	    swash_invlistsvp = hv_fetchs(swash_hv, "V", FALSE);
2789 	    if (swash_invlistsvp) {
2790 		swash_invlist = *swash_invlistsvp;
2791 		invlist_in_swash_is_valid = TRUE;
2792 	    }
2793 	    else {
2794 		swash_invlist = _swash_to_invlist(retval);
2795 		swash_invlist_unclaimed = TRUE;
2796 	    }
2797 	}
2798 
2799 	/* If an inversion list was passed in, have to include it */
2800 	if (invlist) {
2801 
2802             /* Any fetched swash will by now have an inversion list in it;
2803              * otherwise <swash_invlist>  will be NULL, indicating that we
2804              * didn't fetch a swash */
2805 	    if (swash_invlist) {
2806 
2807 		/* Add the passed-in inversion list, which invalidates the one
2808 		 * already stored in the swash */
2809 		invlist_in_swash_is_valid = FALSE;
2810 		_invlist_union(invlist, swash_invlist, &swash_invlist);
2811 	    }
2812 	    else {
2813 
2814                 /* Here, there is no swash already.  Set up a minimal one, if
2815                  * we are going to return a swash */
2816                 if ((int) _invlist_len(invlist) > invlist_swash_boundary) {
2817                     swash_hv = newHV();
2818                     retval = newRV_noinc(MUTABLE_SV(swash_hv));
2819                 }
2820 		swash_invlist = invlist;
2821 	    }
2822 	}
2823 
2824         /* Here, we have computed the union of all the passed-in data.  It may
2825          * be that there was an inversion list in the swash which didn't get
2826          * touched; otherwise save the computed one */
2827 	if (! invlist_in_swash_is_valid
2828             && (int) _invlist_len(swash_invlist) > invlist_swash_boundary)
2829         {
2830 	    if (! hv_stores(MUTABLE_HV(SvRV(retval)), "V", swash_invlist))
2831             {
2832 		Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed");
2833 	    }
2834 	    /* We just stole a reference count. */
2835 	    if (swash_invlist_unclaimed) swash_invlist_unclaimed = FALSE;
2836 	    else SvREFCNT_inc_simple_void_NN(swash_invlist);
2837 	}
2838 
2839         SvREADONLY_on(swash_invlist);
2840 
2841         /* Use the inversion list stand-alone if small enough */
2842         if ((int) _invlist_len(swash_invlist) <= invlist_swash_boundary) {
2843 	    SvREFCNT_dec(retval);
2844 	    if (!swash_invlist_unclaimed)
2845 		SvREFCNT_inc_simple_void_NN(swash_invlist);
2846             retval = newRV_noinc(swash_invlist);
2847         }
2848     }
2849 
2850     CORE_SWASH_INIT_RETURN(retval);
2851 #undef CORE_SWASH_INIT_RETURN
2852 }
2853 
2854 
2855 /* This API is wrong for special case conversions since we may need to
2856  * return several Unicode characters for a single Unicode character
2857  * (see lib/unicore/SpecCase.txt) The SWASHGET in lib/utf8_heavy.pl is
2858  * the lower-level routine, and it is similarly broken for returning
2859  * multiple values.  --jhi
2860  * For those, you should use S__to_utf8_case() instead */
2861 /* Now SWASHGET is recasted into S_swatch_get in this file. */
2862 
2863 /* Note:
2864  * Returns the value of property/mapping C<swash> for the first character
2865  * of the string C<ptr>. If C<do_utf8> is true, the string C<ptr> is
2866  * assumed to be in well-formed UTF-8. If C<do_utf8> is false, the string C<ptr>
2867  * is assumed to be in native 8-bit encoding. Caches the swatch in C<swash>.
2868  *
2869  * A "swash" is a hash which contains initially the keys/values set up by
2870  * SWASHNEW.  The purpose is to be able to completely represent a Unicode
2871  * property for all possible code points.  Things are stored in a compact form
2872  * (see utf8_heavy.pl) so that calculation is required to find the actual
2873  * property value for a given code point.  As code points are looked up, new
2874  * key/value pairs are added to the hash, so that the calculation doesn't have
2875  * to ever be re-done.  Further, each calculation is done, not just for the
2876  * desired one, but for a whole block of code points adjacent to that one.
2877  * For binary properties on ASCII machines, the block is usually for 64 code
2878  * points, starting with a code point evenly divisible by 64.  Thus if the
2879  * property value for code point 257 is requested, the code goes out and
2880  * calculates the property values for all 64 code points between 256 and 319,
2881  * and stores these as a single 64-bit long bit vector, called a "swatch",
2882  * under the key for code point 256.  The key is the UTF-8 encoding for code
2883  * point 256, minus the final byte.  Thus, if the length of the UTF-8 encoding
2884  * for a code point is 13 bytes, the key will be 12 bytes long.  If the value
2885  * for code point 258 is then requested, this code realizes that it would be
2886  * stored under the key for 256, and would find that value and extract the
2887  * relevant bit, offset from 256.
2888  *
2889  * Non-binary properties are stored in as many bits as necessary to represent
2890  * their values (32 currently, though the code is more general than that), not
2891  * as single bits, but the principal is the same: the value for each key is a
2892  * vector that encompasses the property values for all code points whose UTF-8
2893  * representations are represented by the key.  That is, for all code points
2894  * whose UTF-8 representations are length N bytes, and the key is the first N-1
2895  * bytes of that.
2896  */
2897 UV
2898 Perl_swash_fetch(pTHX_ SV *swash, const U8 *ptr, bool do_utf8)
2899 {
2900     HV *const hv = MUTABLE_HV(SvRV(swash));
2901     U32 klen;
2902     U32 off;
2903     STRLEN slen = 0;
2904     STRLEN needents;
2905     const U8 *tmps = NULL;
2906     SV *swatch;
2907     const U8 c = *ptr;
2908 
2909     PERL_ARGS_ASSERT_SWASH_FETCH;
2910 
2911     /* If it really isn't a hash, it isn't really swash; must be an inversion
2912      * list */
2913     if (SvTYPE(hv) != SVt_PVHV) {
2914         return _invlist_contains_cp((SV*)hv,
2915                                     (do_utf8)
2916                                      ? valid_utf8_to_uvchr(ptr, NULL)
2917                                      : c);
2918     }
2919 
2920     /* We store the values in a "swatch" which is a vec() value in a swash
2921      * hash.  Code points 0-255 are a single vec() stored with key length
2922      * (klen) 0.  All other code points have a UTF-8 representation
2923      * 0xAA..0xYY,0xZZ.  A vec() is constructed containing all of them which
2924      * share 0xAA..0xYY, which is the key in the hash to that vec.  So the key
2925      * length for them is the length of the encoded char - 1.  ptr[klen] is the
2926      * final byte in the sequence representing the character */
2927     if (!do_utf8 || UTF8_IS_INVARIANT(c)) {
2928         klen = 0;
2929 	needents = 256;
2930         off = c;
2931     }
2932     else if (UTF8_IS_DOWNGRADEABLE_START(c)) {
2933         klen = 0;
2934 	needents = 256;
2935         off = EIGHT_BIT_UTF8_TO_NATIVE(c, *(ptr + 1));
2936     }
2937     else {
2938         klen = UTF8SKIP(ptr) - 1;
2939 
2940         /* Each vec() stores 2**UTF_ACCUMULATION_SHIFT values.  The offset into
2941          * the vec is the final byte in the sequence.  (In EBCDIC this is
2942          * converted to I8 to get consecutive values.)  To help you visualize
2943          * all this:
2944          *                       Straight 1047   After final byte
2945          *             UTF-8      UTF-EBCDIC     I8 transform
2946          *  U+0400:  \xD0\x80    \xB8\x41\x41    \xB8\x41\xA0
2947          *  U+0401:  \xD0\x81    \xB8\x41\x42    \xB8\x41\xA1
2948          *    ...
2949          *  U+0409:  \xD0\x89    \xB8\x41\x4A    \xB8\x41\xA9
2950          *  U+040A:  \xD0\x8A    \xB8\x41\x51    \xB8\x41\xAA
2951          *    ...
2952          *  U+0412:  \xD0\x92    \xB8\x41\x59    \xB8\x41\xB2
2953          *  U+0413:  \xD0\x93    \xB8\x41\x62    \xB8\x41\xB3
2954          *    ...
2955          *  U+041B:  \xD0\x9B    \xB8\x41\x6A    \xB8\x41\xBB
2956          *  U+041C:  \xD0\x9C    \xB8\x41\x70    \xB8\x41\xBC
2957          *    ...
2958          *  U+041F:  \xD0\x9F    \xB8\x41\x73    \xB8\x41\xBF
2959          *  U+0420:  \xD0\xA0    \xB8\x42\x41    \xB8\x42\x41
2960          *
2961          * (There are no discontinuities in the elided (...) entries.)
2962          * The UTF-8 key for these 33 code points is '\xD0' (which also is the
2963          * key for the next 31, up through U+043F, whose UTF-8 final byte is
2964          * \xBF).  Thus in UTF-8, each key is for a vec() for 64 code points.
2965          * The final UTF-8 byte, which ranges between \x80 and \xBF, is an
2966          * index into the vec() swatch (after subtracting 0x80, which we
2967          * actually do with an '&').
2968          * In UTF-EBCDIC, each key is for a 32 code point vec().  The first 32
2969          * code points above have key '\xB8\x41'. The final UTF-EBCDIC byte has
2970          * dicontinuities which go away by transforming it into I8, and we
2971          * effectively subtract 0xA0 to get the index. */
2972 	needents = (1 << UTF_ACCUMULATION_SHIFT);
2973 	off      = NATIVE_UTF8_TO_I8(ptr[klen]) & UTF_CONTINUATION_MASK;
2974     }
2975 
2976     /*
2977      * This single-entry cache saves about 1/3 of the UTF-8 overhead in test
2978      * suite.  (That is, only 7-8% overall over just a hash cache.  Still,
2979      * it's nothing to sniff at.)  Pity we usually come through at least
2980      * two function calls to get here...
2981      *
2982      * NB: this code assumes that swatches are never modified, once generated!
2983      */
2984 
2985     if (hv   == PL_last_swash_hv &&
2986 	klen == PL_last_swash_klen &&
2987 	(!klen || memEQ((char *)ptr, (char *)PL_last_swash_key, klen)) )
2988     {
2989 	tmps = PL_last_swash_tmps;
2990 	slen = PL_last_swash_slen;
2991     }
2992     else {
2993 	/* Try our second-level swatch cache, kept in a hash. */
2994 	SV** svp = hv_fetch(hv, (const char*)ptr, klen, FALSE);
2995 
2996 	/* If not cached, generate it via swatch_get */
2997 	if (!svp || !SvPOK(*svp)
2998 		 || !(tmps = (const U8*)SvPV_const(*svp, slen)))
2999         {
3000             if (klen) {
3001                 const UV code_point = valid_utf8_to_uvchr(ptr, NULL);
3002                 swatch = swatch_get(swash,
3003                                     code_point & ~((UV)needents - 1),
3004 				    needents);
3005             }
3006             else {  /* For the first 256 code points, the swatch has a key of
3007                        length 0 */
3008                 swatch = swatch_get(swash, 0, needents);
3009             }
3010 
3011 	    if (IN_PERL_COMPILETIME)
3012 		CopHINTS_set(PL_curcop, PL_hints);
3013 
3014 	    svp = hv_store(hv, (const char *)ptr, klen, swatch, 0);
3015 
3016 	    if (!svp || !(tmps = (U8*)SvPV(*svp, slen))
3017 		     || (slen << 3) < needents)
3018 		Perl_croak(aTHX_ "panic: swash_fetch got improper swatch, "
3019 			   "svp=%p, tmps=%p, slen=%"UVuf", needents=%"UVuf,
3020 			   svp, tmps, (UV)slen, (UV)needents);
3021 	}
3022 
3023 	PL_last_swash_hv = hv;
3024 	assert(klen <= sizeof(PL_last_swash_key));
3025 	PL_last_swash_klen = (U8)klen;
3026 	/* FIXME change interpvar.h?  */
3027 	PL_last_swash_tmps = (U8 *) tmps;
3028 	PL_last_swash_slen = slen;
3029 	if (klen)
3030 	    Copy(ptr, PL_last_swash_key, klen, U8);
3031     }
3032 
3033     switch ((int)((slen << 3) / needents)) {
3034     case 1:
3035 	return ((UV) tmps[off >> 3] & (1 << (off & 7))) != 0;
3036     case 8:
3037 	return ((UV) tmps[off]);
3038     case 16:
3039 	off <<= 1;
3040 	return
3041             ((UV) tmps[off    ] << 8) +
3042             ((UV) tmps[off + 1]);
3043     case 32:
3044 	off <<= 2;
3045 	return
3046             ((UV) tmps[off    ] << 24) +
3047             ((UV) tmps[off + 1] << 16) +
3048             ((UV) tmps[off + 2] <<  8) +
3049             ((UV) tmps[off + 3]);
3050     }
3051     Perl_croak(aTHX_ "panic: swash_fetch got swatch of unexpected bit width, "
3052 	       "slen=%"UVuf", needents=%"UVuf, (UV)slen, (UV)needents);
3053     NORETURN_FUNCTION_END;
3054 }
3055 
3056 /* Read a single line of the main body of the swash input text.  These are of
3057  * the form:
3058  * 0053	0056	0073
3059  * where each number is hex.  The first two numbers form the minimum and
3060  * maximum of a range, and the third is the value associated with the range.
3061  * Not all swashes should have a third number
3062  *
3063  * On input: l	  points to the beginning of the line to be examined; it points
3064  *		  to somewhere in the string of the whole input text, and is
3065  *		  terminated by a \n or the null string terminator.
3066  *	     lend   points to the null terminator of that string
3067  *	     wants_value    is non-zero if the swash expects a third number
3068  *	     typestr is the name of the swash's mapping, like 'ToLower'
3069  * On output: *min, *max, and *val are set to the values read from the line.
3070  *	      returns a pointer just beyond the line examined.  If there was no
3071  *	      valid min number on the line, returns lend+1
3072  */
3073 
3074 STATIC U8*
3075 S_swash_scan_list_line(pTHX_ U8* l, U8* const lend, UV* min, UV* max, UV* val,
3076 			     const bool wants_value, const U8* const typestr)
3077 {
3078     const int  typeto  = typestr[0] == 'T' && typestr[1] == 'o';
3079     STRLEN numlen;	    /* Length of the number */
3080     I32 flags = PERL_SCAN_SILENT_ILLDIGIT
3081 		| PERL_SCAN_DISALLOW_PREFIX
3082 		| PERL_SCAN_SILENT_NON_PORTABLE;
3083 
3084     /* nl points to the next \n in the scan */
3085     U8* const nl = (U8*)memchr(l, '\n', lend - l);
3086 
3087     PERL_ARGS_ASSERT_SWASH_SCAN_LIST_LINE;
3088 
3089     /* Get the first number on the line: the range minimum */
3090     numlen = lend - l;
3091     *min = grok_hex((char *)l, &numlen, &flags, NULL);
3092     *max = *min;    /* So can never return without setting max */
3093     if (numlen)	    /* If found a hex number, position past it */
3094 	l += numlen;
3095     else if (nl) {	    /* Else, go handle next line, if any */
3096 	return nl + 1;	/* 1 is length of "\n" */
3097     }
3098     else {		/* Else, no next line */
3099 	return lend + 1;	/* to LIST's end at which \n is not found */
3100     }
3101 
3102     /* The max range value follows, separated by a BLANK */
3103     if (isBLANK(*l)) {
3104 	++l;
3105 	flags = PERL_SCAN_SILENT_ILLDIGIT
3106 		| PERL_SCAN_DISALLOW_PREFIX
3107 		| PERL_SCAN_SILENT_NON_PORTABLE;
3108 	numlen = lend - l;
3109 	*max = grok_hex((char *)l, &numlen, &flags, NULL);
3110 	if (numlen)
3111 	    l += numlen;
3112 	else    /* If no value here, it is a single element range */
3113 	    *max = *min;
3114 
3115 	/* Non-binary tables have a third entry: what the first element of the
3116 	 * range maps to.  The map for those currently read here is in hex */
3117 	if (wants_value) {
3118 	    if (isBLANK(*l)) {
3119 		++l;
3120                 flags = PERL_SCAN_SILENT_ILLDIGIT
3121                     | PERL_SCAN_DISALLOW_PREFIX
3122                     | PERL_SCAN_SILENT_NON_PORTABLE;
3123                 numlen = lend - l;
3124                 *val = grok_hex((char *)l, &numlen, &flags, NULL);
3125                 if (numlen)
3126                     l += numlen;
3127                 else
3128                     *val = 0;
3129 	    }
3130 	    else {
3131 		*val = 0;
3132 		if (typeto) {
3133 		    /* diag_listed_as: To%s: illegal mapping '%s' */
3134 		    Perl_croak(aTHX_ "%s: illegal mapping '%s'",
3135 				     typestr, l);
3136 		}
3137 	    }
3138 	}
3139 	else
3140 	    *val = 0; /* bits == 1, then any val should be ignored */
3141     }
3142     else { /* Nothing following range min, should be single element with no
3143 	      mapping expected */
3144 	if (wants_value) {
3145 	    *val = 0;
3146 	    if (typeto) {
3147 		/* diag_listed_as: To%s: illegal mapping '%s' */
3148 		Perl_croak(aTHX_ "%s: illegal mapping '%s'", typestr, l);
3149 	    }
3150 	}
3151 	else
3152 	    *val = 0; /* bits == 1, then val should be ignored */
3153     }
3154 
3155     /* Position to next line if any, or EOF */
3156     if (nl)
3157 	l = nl + 1;
3158     else
3159 	l = lend;
3160 
3161     return l;
3162 }
3163 
3164 /* Note:
3165  * Returns a swatch (a bit vector string) for a code point sequence
3166  * that starts from the value C<start> and comprises the number C<span>.
3167  * A C<swash> must be an object created by SWASHNEW (see lib/utf8_heavy.pl).
3168  * Should be used via swash_fetch, which will cache the swatch in C<swash>.
3169  */
3170 STATIC SV*
3171 S_swatch_get(pTHX_ SV* swash, UV start, UV span)
3172 {
3173     SV *swatch;
3174     U8 *l, *lend, *x, *xend, *s, *send;
3175     STRLEN lcur, xcur, scur;
3176     HV *const hv = MUTABLE_HV(SvRV(swash));
3177     SV** const invlistsvp = hv_fetchs(hv, "V", FALSE);
3178 
3179     SV** listsvp = NULL; /* The string containing the main body of the table */
3180     SV** extssvp = NULL;
3181     SV** invert_it_svp = NULL;
3182     U8* typestr = NULL;
3183     STRLEN bits;
3184     STRLEN octets; /* if bits == 1, then octets == 0 */
3185     UV  none;
3186     UV  end = start + span;
3187 
3188     if (invlistsvp == NULL) {
3189         SV** const bitssvp = hv_fetchs(hv, "BITS", FALSE);
3190         SV** const nonesvp = hv_fetchs(hv, "NONE", FALSE);
3191         SV** const typesvp = hv_fetchs(hv, "TYPE", FALSE);
3192         extssvp = hv_fetchs(hv, "EXTRAS", FALSE);
3193         listsvp = hv_fetchs(hv, "LIST", FALSE);
3194         invert_it_svp = hv_fetchs(hv, "INVERT_IT", FALSE);
3195 
3196 	bits  = SvUV(*bitssvp);
3197 	none  = SvUV(*nonesvp);
3198 	typestr = (U8*)SvPV_nolen(*typesvp);
3199     }
3200     else {
3201 	bits = 1;
3202 	none = 0;
3203     }
3204     octets = bits >> 3; /* if bits == 1, then octets == 0 */
3205 
3206     PERL_ARGS_ASSERT_SWATCH_GET;
3207 
3208     if (bits != 1 && bits != 8 && bits != 16 && bits != 32) {
3209 	Perl_croak(aTHX_ "panic: swatch_get doesn't expect bits %"UVuf,
3210 						 (UV)bits);
3211     }
3212 
3213     /* If overflowed, use the max possible */
3214     if (end < start) {
3215 	end = UV_MAX;
3216 	span = end - start;
3217     }
3218 
3219     /* create and initialize $swatch */
3220     scur   = octets ? (span * octets) : (span + 7) / 8;
3221     swatch = newSV(scur);
3222     SvPOK_on(swatch);
3223     s = (U8*)SvPVX(swatch);
3224     if (octets && none) {
3225 	const U8* const e = s + scur;
3226 	while (s < e) {
3227 	    if (bits == 8)
3228 		*s++ = (U8)(none & 0xff);
3229 	    else if (bits == 16) {
3230 		*s++ = (U8)((none >>  8) & 0xff);
3231 		*s++ = (U8)( none        & 0xff);
3232 	    }
3233 	    else if (bits == 32) {
3234 		*s++ = (U8)((none >> 24) & 0xff);
3235 		*s++ = (U8)((none >> 16) & 0xff);
3236 		*s++ = (U8)((none >>  8) & 0xff);
3237 		*s++ = (U8)( none        & 0xff);
3238 	    }
3239 	}
3240 	*s = '\0';
3241     }
3242     else {
3243 	(void)memzero((U8*)s, scur + 1);
3244     }
3245     SvCUR_set(swatch, scur);
3246     s = (U8*)SvPVX(swatch);
3247 
3248     if (invlistsvp) {	/* If has an inversion list set up use that */
3249 	_invlist_populate_swatch(*invlistsvp, start, end, s);
3250         return swatch;
3251     }
3252 
3253     /* read $swash->{LIST} */
3254     l = (U8*)SvPV(*listsvp, lcur);
3255     lend = l + lcur;
3256     while (l < lend) {
3257 	UV min, max, val, upper;
3258 	l = swash_scan_list_line(l, lend, &min, &max, &val,
3259                                                         cBOOL(octets), typestr);
3260 	if (l > lend) {
3261 	    break;
3262 	}
3263 
3264 	/* If looking for something beyond this range, go try the next one */
3265 	if (max < start)
3266 	    continue;
3267 
3268 	/* <end> is generally 1 beyond where we want to set things, but at the
3269 	 * platform's infinity, where we can't go any higher, we want to
3270 	 * include the code point at <end> */
3271         upper = (max < end)
3272                 ? max
3273                 : (max != UV_MAX || end != UV_MAX)
3274                   ? end - 1
3275                   : end;
3276 
3277 	if (octets) {
3278 	    UV key;
3279 	    if (min < start) {
3280 		if (!none || val < none) {
3281 		    val += start - min;
3282 		}
3283 		min = start;
3284 	    }
3285 	    for (key = min; key <= upper; key++) {
3286 		STRLEN offset;
3287 		/* offset must be non-negative (start <= min <= key < end) */
3288 		offset = octets * (key - start);
3289 		if (bits == 8)
3290 		    s[offset] = (U8)(val & 0xff);
3291 		else if (bits == 16) {
3292 		    s[offset    ] = (U8)((val >>  8) & 0xff);
3293 		    s[offset + 1] = (U8)( val        & 0xff);
3294 		}
3295 		else if (bits == 32) {
3296 		    s[offset    ] = (U8)((val >> 24) & 0xff);
3297 		    s[offset + 1] = (U8)((val >> 16) & 0xff);
3298 		    s[offset + 2] = (U8)((val >>  8) & 0xff);
3299 		    s[offset + 3] = (U8)( val        & 0xff);
3300 		}
3301 
3302 		if (!none || val < none)
3303 		    ++val;
3304 	    }
3305 	}
3306 	else { /* bits == 1, then val should be ignored */
3307 	    UV key;
3308 	    if (min < start)
3309 		min = start;
3310 
3311 	    for (key = min; key <= upper; key++) {
3312 		const STRLEN offset = (STRLEN)(key - start);
3313 		s[offset >> 3] |= 1 << (offset & 7);
3314 	    }
3315 	}
3316     } /* while */
3317 
3318     /* Invert if the data says it should be.  Assumes that bits == 1 */
3319     if (invert_it_svp && SvUV(*invert_it_svp)) {
3320 
3321 	/* Unicode properties should come with all bits above PERL_UNICODE_MAX
3322 	 * be 0, and their inversion should also be 0, as we don't succeed any
3323 	 * Unicode property matches for non-Unicode code points */
3324 	if (start <= PERL_UNICODE_MAX) {
3325 
3326 	    /* The code below assumes that we never cross the
3327 	     * Unicode/above-Unicode boundary in a range, as otherwise we would
3328 	     * have to figure out where to stop flipping the bits.  Since this
3329 	     * boundary is divisible by a large power of 2, and swatches comes
3330 	     * in small powers of 2, this should be a valid assumption */
3331 	    assert(start + span - 1 <= PERL_UNICODE_MAX);
3332 
3333 	    send = s + scur;
3334 	    while (s < send) {
3335 		*s = ~(*s);
3336 		s++;
3337 	    }
3338 	}
3339     }
3340 
3341     /* read $swash->{EXTRAS}
3342      * This code also copied to swash_to_invlist() below */
3343     x = (U8*)SvPV(*extssvp, xcur);
3344     xend = x + xcur;
3345     while (x < xend) {
3346 	STRLEN namelen;
3347 	U8 *namestr;
3348 	SV** othersvp;
3349 	HV* otherhv;
3350 	STRLEN otherbits;
3351 	SV **otherbitssvp, *other;
3352 	U8 *s, *o, *nl;
3353 	STRLEN slen, olen;
3354 
3355 	const U8 opc = *x++;
3356 	if (opc == '\n')
3357 	    continue;
3358 
3359 	nl = (U8*)memchr(x, '\n', xend - x);
3360 
3361 	if (opc != '-' && opc != '+' && opc != '!' && opc != '&') {
3362 	    if (nl) {
3363 		x = nl + 1; /* 1 is length of "\n" */
3364 		continue;
3365 	    }
3366 	    else {
3367 		x = xend; /* to EXTRAS' end at which \n is not found */
3368 		break;
3369 	    }
3370 	}
3371 
3372 	namestr = x;
3373 	if (nl) {
3374 	    namelen = nl - namestr;
3375 	    x = nl + 1;
3376 	}
3377 	else {
3378 	    namelen = xend - namestr;
3379 	    x = xend;
3380 	}
3381 
3382 	othersvp = hv_fetch(hv, (char *)namestr, namelen, FALSE);
3383 	otherhv = MUTABLE_HV(SvRV(*othersvp));
3384 	otherbitssvp = hv_fetchs(otherhv, "BITS", FALSE);
3385 	otherbits = (STRLEN)SvUV(*otherbitssvp);
3386 	if (bits < otherbits)
3387 	    Perl_croak(aTHX_ "panic: swatch_get found swatch size mismatch, "
3388 		       "bits=%"UVuf", otherbits=%"UVuf, (UV)bits, (UV)otherbits);
3389 
3390 	/* The "other" swatch must be destroyed after. */
3391 	other = swatch_get(*othersvp, start, span);
3392 	o = (U8*)SvPV(other, olen);
3393 
3394 	if (!olen)
3395 	    Perl_croak(aTHX_ "panic: swatch_get got improper swatch");
3396 
3397 	s = (U8*)SvPV(swatch, slen);
3398 	if (bits == 1 && otherbits == 1) {
3399 	    if (slen != olen)
3400 		Perl_croak(aTHX_ "panic: swatch_get found swatch length "
3401 			   "mismatch, slen=%"UVuf", olen=%"UVuf,
3402 			   (UV)slen, (UV)olen);
3403 
3404 	    switch (opc) {
3405 	    case '+':
3406 		while (slen--)
3407 		    *s++ |= *o++;
3408 		break;
3409 	    case '!':
3410 		while (slen--)
3411 		    *s++ |= ~*o++;
3412 		break;
3413 	    case '-':
3414 		while (slen--)
3415 		    *s++ &= ~*o++;
3416 		break;
3417 	    case '&':
3418 		while (slen--)
3419 		    *s++ &= *o++;
3420 		break;
3421 	    default:
3422 		break;
3423 	    }
3424 	}
3425 	else {
3426 	    STRLEN otheroctets = otherbits >> 3;
3427 	    STRLEN offset = 0;
3428 	    U8* const send = s + slen;
3429 
3430 	    while (s < send) {
3431 		UV otherval = 0;
3432 
3433 		if (otherbits == 1) {
3434 		    otherval = (o[offset >> 3] >> (offset & 7)) & 1;
3435 		    ++offset;
3436 		}
3437 		else {
3438 		    STRLEN vlen = otheroctets;
3439 		    otherval = *o++;
3440 		    while (--vlen) {
3441 			otherval <<= 8;
3442 			otherval |= *o++;
3443 		    }
3444 		}
3445 
3446 		if (opc == '+' && otherval)
3447 		    NOOP;   /* replace with otherval */
3448 		else if (opc == '!' && !otherval)
3449 		    otherval = 1;
3450 		else if (opc == '-' && otherval)
3451 		    otherval = 0;
3452 		else if (opc == '&' && !otherval)
3453 		    otherval = 0;
3454 		else {
3455 		    s += octets; /* no replacement */
3456 		    continue;
3457 		}
3458 
3459 		if (bits == 8)
3460 		    *s++ = (U8)( otherval & 0xff);
3461 		else if (bits == 16) {
3462 		    *s++ = (U8)((otherval >>  8) & 0xff);
3463 		    *s++ = (U8)( otherval        & 0xff);
3464 		}
3465 		else if (bits == 32) {
3466 		    *s++ = (U8)((otherval >> 24) & 0xff);
3467 		    *s++ = (U8)((otherval >> 16) & 0xff);
3468 		    *s++ = (U8)((otherval >>  8) & 0xff);
3469 		    *s++ = (U8)( otherval        & 0xff);
3470 		}
3471 	    }
3472 	}
3473 	sv_free(other); /* through with it! */
3474     } /* while */
3475     return swatch;
3476 }
3477 
3478 HV*
3479 Perl__swash_inversion_hash(pTHX_ SV* const swash)
3480 {
3481 
3482    /* Subject to change or removal.  For use only in regcomp.c and regexec.c
3483     * Can't be used on a property that is subject to user override, as it
3484     * relies on the value of SPECIALS in the swash which would be set by
3485     * utf8_heavy.pl to the hash in the non-overriden file, and hence is not set
3486     * for overridden properties
3487     *
3488     * Returns a hash which is the inversion and closure of a swash mapping.
3489     * For example, consider the input lines:
3490     * 004B		006B
3491     * 004C		006C
3492     * 212A		006B
3493     *
3494     * The returned hash would have two keys, the UTF-8 for 006B and the UTF-8 for
3495     * 006C.  The value for each key is an array.  For 006C, the array would
3496     * have two elements, the UTF-8 for itself, and for 004C.  For 006B, there
3497     * would be three elements in its array, the UTF-8 for 006B, 004B and 212A.
3498     *
3499     * Note that there are no elements in the hash for 004B, 004C, 212A.  The
3500     * keys are only code points that are folded-to, so it isn't a full closure.
3501     *
3502     * Essentially, for any code point, it gives all the code points that map to
3503     * it, or the list of 'froms' for that point.
3504     *
3505     * Currently it ignores any additions or deletions from other swashes,
3506     * looking at just the main body of the swash, and if there are SPECIALS
3507     * in the swash, at that hash
3508     *
3509     * The specials hash can be extra code points, and most likely consists of
3510     * maps from single code points to multiple ones (each expressed as a string
3511     * of UTF-8 characters).   This function currently returns only 1-1 mappings.
3512     * However consider this possible input in the specials hash:
3513     * "\xEF\xAC\x85" => "\x{0073}\x{0074}",         # U+FB05 => 0073 0074
3514     * "\xEF\xAC\x86" => "\x{0073}\x{0074}",         # U+FB06 => 0073 0074
3515     *
3516     * Both FB05 and FB06 map to the same multi-char sequence, which we don't
3517     * currently handle.  But it also means that FB05 and FB06 are equivalent in
3518     * a 1-1 mapping which we should handle, and this relationship may not be in
3519     * the main table.  Therefore this function examines all the multi-char
3520     * sequences and adds the 1-1 mappings that come out of that.
3521     *
3522     * XXX This function was originally intended to be multipurpose, but its
3523     * only use is quite likely to remain for constructing the inversion of
3524     * the CaseFolding (//i) property.  If it were more general purpose for
3525     * regex patterns, it would have to do the FB05/FB06 game for simple folds,
3526     * because certain folds are prohibited under /iaa and /il.  As an example,
3527     * in Unicode 3.0.1 both U+0130 and U+0131 fold to 'i', and hence are both
3528     * equivalent under /i.  But under /iaa and /il, the folds to 'i' are
3529     * prohibited, so we would not figure out that they fold to each other.
3530     * Code could be written to automatically figure this out, similar to the
3531     * code that does this for multi-character folds, but this is the only case
3532     * where something like this is ever likely to happen, as all the single
3533     * char folds to the 0-255 range are now quite settled.  Instead there is a
3534     * little special code that is compiled only for this Unicode version.  This
3535     * is smaller and didn't require much coding time to do.  But this makes
3536     * this routine strongly tied to being used just for CaseFolding.  If ever
3537     * it should be generalized, this would have to be fixed */
3538 
3539     U8 *l, *lend;
3540     STRLEN lcur;
3541     HV *const hv = MUTABLE_HV(SvRV(swash));
3542 
3543     /* The string containing the main body of the table.  This will have its
3544      * assertion fail if the swash has been converted to its inversion list */
3545     SV** const listsvp = hv_fetchs(hv, "LIST", FALSE);
3546 
3547     SV** const typesvp = hv_fetchs(hv, "TYPE", FALSE);
3548     SV** const bitssvp = hv_fetchs(hv, "BITS", FALSE);
3549     SV** const nonesvp = hv_fetchs(hv, "NONE", FALSE);
3550     /*SV** const extssvp = hv_fetchs(hv, "EXTRAS", FALSE);*/
3551     const U8* const typestr = (U8*)SvPV_nolen(*typesvp);
3552     const STRLEN bits  = SvUV(*bitssvp);
3553     const STRLEN octets = bits >> 3; /* if bits == 1, then octets == 0 */
3554     const UV     none  = SvUV(*nonesvp);
3555     SV **specials_p = hv_fetchs(hv, "SPECIALS", 0);
3556 
3557     HV* ret = newHV();
3558 
3559     PERL_ARGS_ASSERT__SWASH_INVERSION_HASH;
3560 
3561     /* Must have at least 8 bits to get the mappings */
3562     if (bits != 8 && bits != 16 && bits != 32) {
3563 	Perl_croak(aTHX_ "panic: swash_inversion_hash doesn't expect bits %"UVuf,
3564 						 (UV)bits);
3565     }
3566 
3567     if (specials_p) { /* It might be "special" (sometimes, but not always, a
3568 			mapping to more than one character */
3569 
3570 	/* Construct an inverse mapping hash for the specials */
3571 	HV * const specials_hv = MUTABLE_HV(SvRV(*specials_p));
3572 	HV * specials_inverse = newHV();
3573 	char *char_from; /* the lhs of the map */
3574 	I32 from_len;   /* its byte length */
3575 	char *char_to;  /* the rhs of the map */
3576 	I32 to_len;	/* its byte length */
3577 	SV *sv_to;	/* and in a sv */
3578 	AV* from_list;  /* list of things that map to each 'to' */
3579 
3580 	hv_iterinit(specials_hv);
3581 
3582 	/* The keys are the characters (in UTF-8) that map to the corresponding
3583 	 * UTF-8 string value.  Iterate through the list creating the inverse
3584 	 * list. */
3585 	while ((sv_to = hv_iternextsv(specials_hv, &char_from, &from_len))) {
3586 	    SV** listp;
3587 	    if (! SvPOK(sv_to)) {
3588 		Perl_croak(aTHX_ "panic: value returned from hv_iternextsv() "
3589 			   "unexpectedly is not a string, flags=%lu",
3590 			   (unsigned long)SvFLAGS(sv_to));
3591 	    }
3592 	    /*DEBUG_U(PerlIO_printf(Perl_debug_log, "Found mapping from %"UVXf", First char of to is %"UVXf"\n", valid_utf8_to_uvchr((U8*) char_from, 0), valid_utf8_to_uvchr((U8*) SvPVX(sv_to), 0)));*/
3593 
3594 	    /* Each key in the inverse list is a mapped-to value, and the key's
3595 	     * hash value is a list of the strings (each in UTF-8) that map to
3596 	     * it.  Those strings are all one character long */
3597 	    if ((listp = hv_fetch(specials_inverse,
3598 				    SvPVX(sv_to),
3599 				    SvCUR(sv_to), 0)))
3600 	    {
3601 		from_list = (AV*) *listp;
3602 	    }
3603 	    else { /* No entry yet for it: create one */
3604 		from_list = newAV();
3605 		if (! hv_store(specials_inverse,
3606 				SvPVX(sv_to),
3607 				SvCUR(sv_to),
3608 				(SV*) from_list, 0))
3609 		{
3610 		    Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed");
3611 		}
3612 	    }
3613 
3614 	    /* Here have the list associated with this 'to' (perhaps newly
3615 	     * created and empty).  Just add to it.  Note that we ASSUME that
3616 	     * the input is guaranteed to not have duplications, so we don't
3617 	     * check for that.  Duplications just slow down execution time. */
3618 	    av_push(from_list, newSVpvn_utf8(char_from, from_len, TRUE));
3619 	}
3620 
3621 	/* Here, 'specials_inverse' contains the inverse mapping.  Go through
3622 	 * it looking for cases like the FB05/FB06 examples above.  There would
3623 	 * be an entry in the hash like
3624 	*	'st' => [ FB05, FB06 ]
3625 	* In this example we will create two lists that get stored in the
3626 	* returned hash, 'ret':
3627 	*	FB05 => [ FB05, FB06 ]
3628 	*	FB06 => [ FB05, FB06 ]
3629 	*
3630 	* Note that there is nothing to do if the array only has one element.
3631 	* (In the normal 1-1 case handled below, we don't have to worry about
3632 	* two lists, as everything gets tied to the single list that is
3633 	* generated for the single character 'to'.  But here, we are omitting
3634 	* that list, ('st' in the example), so must have multiple lists.) */
3635 	while ((from_list = (AV *) hv_iternextsv(specials_inverse,
3636 						 &char_to, &to_len)))
3637 	{
3638 	    if (av_tindex_nomg(from_list) > 0) {
3639 		SSize_t i;
3640 
3641 		/* We iterate over all combinations of i,j to place each code
3642 		 * point on each list */
3643 		for (i = 0; i <= av_tindex_nomg(from_list); i++) {
3644 		    SSize_t j;
3645 		    AV* i_list = newAV();
3646 		    SV** entryp = av_fetch(from_list, i, FALSE);
3647 		    if (entryp == NULL) {
3648 			Perl_croak(aTHX_ "panic: av_fetch() unexpectedly failed");
3649 		    }
3650 		    if (hv_fetch(ret, SvPVX(*entryp), SvCUR(*entryp), FALSE)) {
3651 			Perl_croak(aTHX_ "panic: unexpected entry for %s", SvPVX(*entryp));
3652 		    }
3653 		    if (! hv_store(ret, SvPVX(*entryp), SvCUR(*entryp),
3654 				   (SV*) i_list, FALSE))
3655 		    {
3656 			Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed");
3657 		    }
3658 
3659 		    /* For DEBUG_U: UV u = valid_utf8_to_uvchr((U8*) SvPVX(*entryp), 0);*/
3660 		    for (j = 0; j <= av_tindex_nomg(from_list); j++) {
3661 			entryp = av_fetch(from_list, j, FALSE);
3662 			if (entryp == NULL) {
3663 			    Perl_croak(aTHX_ "panic: av_fetch() unexpectedly failed");
3664 			}
3665 
3666 			/* When i==j this adds itself to the list */
3667 			av_push(i_list, newSVuv(utf8_to_uvchr_buf(
3668 					(U8*) SvPVX(*entryp),
3669 					(U8*) SvPVX(*entryp) + SvCUR(*entryp),
3670 					0)));
3671 			/*DEBUG_U(PerlIO_printf(Perl_debug_log, "%s: %d: Adding %"UVXf" to list for %"UVXf"\n", __FILE__, __LINE__, valid_utf8_to_uvchr((U8*) SvPVX(*entryp), 0), u));*/
3672 		    }
3673 		}
3674 	    }
3675 	}
3676 	SvREFCNT_dec(specials_inverse); /* done with it */
3677     } /* End of specials */
3678 
3679     /* read $swash->{LIST} */
3680 
3681 #if    UNICODE_MAJOR_VERSION   == 3         \
3682     && UNICODE_DOT_VERSION     == 0         \
3683     && UNICODE_DOT_DOT_VERSION == 1
3684 
3685     /* For this version only U+130 and U+131 are equivalent under qr//i.  Add a
3686      * rule so that things work under /iaa and /il */
3687 
3688     SV * mod_listsv = sv_mortalcopy(*listsvp);
3689     sv_catpv(mod_listsv, "130\t130\t131\n");
3690     l = (U8*)SvPV(mod_listsv, lcur);
3691 
3692 #else
3693 
3694     l = (U8*)SvPV(*listsvp, lcur);
3695 
3696 #endif
3697 
3698     lend = l + lcur;
3699 
3700     /* Go through each input line */
3701     while (l < lend) {
3702 	UV min, max, val;
3703 	UV inverse;
3704 	l = swash_scan_list_line(l, lend, &min, &max, &val,
3705                                                      cBOOL(octets), typestr);
3706 	if (l > lend) {
3707 	    break;
3708 	}
3709 
3710 	/* Each element in the range is to be inverted */
3711 	for (inverse = min; inverse <= max; inverse++) {
3712 	    AV* list;
3713 	    SV** listp;
3714 	    IV i;
3715 	    bool found_key = FALSE;
3716 	    bool found_inverse = FALSE;
3717 
3718 	    /* The key is the inverse mapping */
3719 	    char key[UTF8_MAXBYTES+1];
3720 	    char* key_end = (char *) uvchr_to_utf8((U8*) key, val);
3721 	    STRLEN key_len = key_end - key;
3722 
3723 	    /* Get the list for the map */
3724 	    if ((listp = hv_fetch(ret, key, key_len, FALSE))) {
3725 		list = (AV*) *listp;
3726 	    }
3727 	    else { /* No entry yet for it: create one */
3728 		list = newAV();
3729 		if (! hv_store(ret, key, key_len, (SV*) list, FALSE)) {
3730 		    Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed");
3731 		}
3732 	    }
3733 
3734 	    /* Look through list to see if this inverse mapping already is
3735 	     * listed, or if there is a mapping to itself already */
3736 	    for (i = 0; i <= av_tindex_nomg(list); i++) {
3737 		SV** entryp = av_fetch(list, i, FALSE);
3738 		SV* entry;
3739 		UV uv;
3740 		if (entryp == NULL) {
3741 		    Perl_croak(aTHX_ "panic: av_fetch() unexpectedly failed");
3742 		}
3743 		entry = *entryp;
3744 		uv = SvUV(entry);
3745 		/*DEBUG_U(PerlIO_printf(Perl_debug_log, "list for %"UVXf" contains %"UVXf"\n", val, uv));*/
3746 		if (uv == val) {
3747 		    found_key = TRUE;
3748 		}
3749 		if (uv == inverse) {
3750 		    found_inverse = TRUE;
3751 		}
3752 
3753 		/* No need to continue searching if found everything we are
3754 		 * looking for */
3755 		if (found_key && found_inverse) {
3756 		    break;
3757 		}
3758 	    }
3759 
3760 	    /* Make sure there is a mapping to itself on the list */
3761 	    if (! found_key) {
3762 		av_push(list, newSVuv(val));
3763 		/*DEBUG_U(PerlIO_printf(Perl_debug_log, "%s: %d: Adding %"UVXf" to list for %"UVXf"\n", __FILE__, __LINE__, val, val));*/
3764 	    }
3765 
3766 
3767 	    /* Simply add the value to the list */
3768 	    if (! found_inverse) {
3769 		av_push(list, newSVuv(inverse));
3770 		/*DEBUG_U(PerlIO_printf(Perl_debug_log, "%s: %d: Adding %"UVXf" to list for %"UVXf"\n", __FILE__, __LINE__, inverse, val));*/
3771 	    }
3772 
3773 	    /* swatch_get() increments the value of val for each element in the
3774 	     * range.  That makes more compact tables possible.  You can
3775 	     * express the capitalization, for example, of all consecutive
3776 	     * letters with a single line: 0061\t007A\t0041 This maps 0061 to
3777 	     * 0041, 0062 to 0042, etc.  I (khw) have never understood 'none',
3778 	     * and it's not documented; it appears to be used only in
3779 	     * implementing tr//; I copied the semantics from swatch_get(), just
3780 	     * in case */
3781 	    if (!none || val < none) {
3782 		++val;
3783 	    }
3784 	}
3785     }
3786 
3787     return ret;
3788 }
3789 
3790 SV*
3791 Perl__swash_to_invlist(pTHX_ SV* const swash)
3792 {
3793 
3794    /* Subject to change or removal.  For use only in one place in regcomp.c.
3795     * Ownership is given to one reference count in the returned SV* */
3796 
3797     U8 *l, *lend;
3798     char *loc;
3799     STRLEN lcur;
3800     HV *const hv = MUTABLE_HV(SvRV(swash));
3801     UV elements = 0;    /* Number of elements in the inversion list */
3802     U8 empty[] = "";
3803     SV** listsvp;
3804     SV** typesvp;
3805     SV** bitssvp;
3806     SV** extssvp;
3807     SV** invert_it_svp;
3808 
3809     U8* typestr;
3810     STRLEN bits;
3811     STRLEN octets; /* if bits == 1, then octets == 0 */
3812     U8 *x, *xend;
3813     STRLEN xcur;
3814 
3815     SV* invlist;
3816 
3817     PERL_ARGS_ASSERT__SWASH_TO_INVLIST;
3818 
3819     /* If not a hash, it must be the swash's inversion list instead */
3820     if (SvTYPE(hv) != SVt_PVHV) {
3821         return SvREFCNT_inc_simple_NN((SV*) hv);
3822     }
3823 
3824     /* The string containing the main body of the table */
3825     listsvp = hv_fetchs(hv, "LIST", FALSE);
3826     typesvp = hv_fetchs(hv, "TYPE", FALSE);
3827     bitssvp = hv_fetchs(hv, "BITS", FALSE);
3828     extssvp = hv_fetchs(hv, "EXTRAS", FALSE);
3829     invert_it_svp = hv_fetchs(hv, "INVERT_IT", FALSE);
3830 
3831     typestr = (U8*)SvPV_nolen(*typesvp);
3832     bits  = SvUV(*bitssvp);
3833     octets = bits >> 3; /* if bits == 1, then octets == 0 */
3834 
3835     /* read $swash->{LIST} */
3836     if (SvPOK(*listsvp)) {
3837 	l = (U8*)SvPV(*listsvp, lcur);
3838     }
3839     else {
3840 	/* LIST legitimately doesn't contain a string during compilation phases
3841 	 * of Perl itself, before the Unicode tables are generated.  In this
3842 	 * case, just fake things up by creating an empty list */
3843 	l = empty;
3844 	lcur = 0;
3845     }
3846     loc = (char *) l;
3847     lend = l + lcur;
3848 
3849     if (*l == 'V') {    /*  Inversion list format */
3850         const char *after_atou = (char *) lend;
3851         UV element0;
3852         UV* other_elements_ptr;
3853 
3854         /* The first number is a count of the rest */
3855         l++;
3856         if (!grok_atoUV((const char *)l, &elements, &after_atou)) {
3857             Perl_croak(aTHX_ "panic: Expecting a valid count of elements at start of inversion list");
3858         }
3859         if (elements == 0) {
3860             invlist = _new_invlist(0);
3861         }
3862         else {
3863             while (isSPACE(*l)) l++;
3864             l = (U8 *) after_atou;
3865 
3866             /* Get the 0th element, which is needed to setup the inversion list */
3867             while (isSPACE(*l)) l++;
3868             if (!grok_atoUV((const char *)l, &element0, &after_atou)) {
3869                 Perl_croak(aTHX_ "panic: Expecting a valid 0th element for inversion list");
3870             }
3871             l = (U8 *) after_atou;
3872             invlist = _setup_canned_invlist(elements, element0, &other_elements_ptr);
3873             elements--;
3874 
3875             /* Then just populate the rest of the input */
3876             while (elements-- > 0) {
3877                 if (l > lend) {
3878                     Perl_croak(aTHX_ "panic: Expecting %"UVuf" more elements than available", elements);
3879                 }
3880                 while (isSPACE(*l)) l++;
3881                 if (!grok_atoUV((const char *)l, other_elements_ptr++, &after_atou)) {
3882                     Perl_croak(aTHX_ "panic: Expecting a valid element in inversion list");
3883                 }
3884                 l = (U8 *) after_atou;
3885             }
3886         }
3887     }
3888     else {
3889 
3890         /* Scan the input to count the number of lines to preallocate array
3891          * size based on worst possible case, which is each line in the input
3892          * creates 2 elements in the inversion list: 1) the beginning of a
3893          * range in the list; 2) the beginning of a range not in the list.  */
3894         while ((loc = (strchr(loc, '\n'))) != NULL) {
3895             elements += 2;
3896             loc++;
3897         }
3898 
3899         /* If the ending is somehow corrupt and isn't a new line, add another
3900          * element for the final range that isn't in the inversion list */
3901         if (! (*lend == '\n'
3902             || (*lend == '\0' && (lcur == 0 || *(lend - 1) == '\n'))))
3903         {
3904             elements++;
3905         }
3906 
3907         invlist = _new_invlist(elements);
3908 
3909         /* Now go through the input again, adding each range to the list */
3910         while (l < lend) {
3911             UV start, end;
3912             UV val;		/* Not used by this function */
3913 
3914             l = swash_scan_list_line(l, lend, &start, &end, &val,
3915                                                         cBOOL(octets), typestr);
3916 
3917             if (l > lend) {
3918                 break;
3919             }
3920 
3921             invlist = _add_range_to_invlist(invlist, start, end);
3922         }
3923     }
3924 
3925     /* Invert if the data says it should be */
3926     if (invert_it_svp && SvUV(*invert_it_svp)) {
3927 	_invlist_invert(invlist);
3928     }
3929 
3930     /* This code is copied from swatch_get()
3931      * read $swash->{EXTRAS} */
3932     x = (U8*)SvPV(*extssvp, xcur);
3933     xend = x + xcur;
3934     while (x < xend) {
3935 	STRLEN namelen;
3936 	U8 *namestr;
3937 	SV** othersvp;
3938 	HV* otherhv;
3939 	STRLEN otherbits;
3940 	SV **otherbitssvp, *other;
3941 	U8 *nl;
3942 
3943 	const U8 opc = *x++;
3944 	if (opc == '\n')
3945 	    continue;
3946 
3947 	nl = (U8*)memchr(x, '\n', xend - x);
3948 
3949 	if (opc != '-' && opc != '+' && opc != '!' && opc != '&') {
3950 	    if (nl) {
3951 		x = nl + 1; /* 1 is length of "\n" */
3952 		continue;
3953 	    }
3954 	    else {
3955 		x = xend; /* to EXTRAS' end at which \n is not found */
3956 		break;
3957 	    }
3958 	}
3959 
3960 	namestr = x;
3961 	if (nl) {
3962 	    namelen = nl - namestr;
3963 	    x = nl + 1;
3964 	}
3965 	else {
3966 	    namelen = xend - namestr;
3967 	    x = xend;
3968 	}
3969 
3970 	othersvp = hv_fetch(hv, (char *)namestr, namelen, FALSE);
3971 	otherhv = MUTABLE_HV(SvRV(*othersvp));
3972 	otherbitssvp = hv_fetchs(otherhv, "BITS", FALSE);
3973 	otherbits = (STRLEN)SvUV(*otherbitssvp);
3974 
3975 	if (bits != otherbits || bits != 1) {
3976 	    Perl_croak(aTHX_ "panic: _swash_to_invlist only operates on boolean "
3977 		       "properties, bits=%"UVuf", otherbits=%"UVuf,
3978 		       (UV)bits, (UV)otherbits);
3979 	}
3980 
3981 	/* The "other" swatch must be destroyed after. */
3982 	other = _swash_to_invlist((SV *)*othersvp);
3983 
3984 	/* End of code copied from swatch_get() */
3985 	switch (opc) {
3986 	case '+':
3987 	    _invlist_union(invlist, other, &invlist);
3988 	    break;
3989 	case '!':
3990             _invlist_union_maybe_complement_2nd(invlist, other, TRUE, &invlist);
3991 	    break;
3992 	case '-':
3993 	    _invlist_subtract(invlist, other, &invlist);
3994 	    break;
3995 	case '&':
3996 	    _invlist_intersection(invlist, other, &invlist);
3997 	    break;
3998 	default:
3999 	    break;
4000 	}
4001 	sv_free(other); /* through with it! */
4002     }
4003 
4004     SvREADONLY_on(invlist);
4005     return invlist;
4006 }
4007 
4008 SV*
4009 Perl__get_swash_invlist(pTHX_ SV* const swash)
4010 {
4011     SV** ptr;
4012 
4013     PERL_ARGS_ASSERT__GET_SWASH_INVLIST;
4014 
4015     if (! SvROK(swash)) {
4016         return NULL;
4017     }
4018 
4019     /* If it really isn't a hash, it isn't really swash; must be an inversion
4020      * list */
4021     if (SvTYPE(SvRV(swash)) != SVt_PVHV) {
4022         return SvRV(swash);
4023     }
4024 
4025     ptr = hv_fetchs(MUTABLE_HV(SvRV(swash)), "V", FALSE);
4026     if (! ptr) {
4027         return NULL;
4028     }
4029 
4030     return *ptr;
4031 }
4032 
4033 bool
4034 Perl_check_utf8_print(pTHX_ const U8* s, const STRLEN len)
4035 {
4036     /* May change: warns if surrogates, non-character code points, or
4037      * non-Unicode code points are in s which has length len bytes.  Returns
4038      * TRUE if none found; FALSE otherwise.  The only other validity check is
4039      * to make sure that this won't exceed the string's length.
4040      *
4041      * Code points above the platform's C<IV_MAX> will raise a deprecation
4042      * warning, unless those are turned off.  */
4043 
4044     const U8* const e = s + len;
4045     bool ok = TRUE;
4046 
4047     PERL_ARGS_ASSERT_CHECK_UTF8_PRINT;
4048 
4049     while (s < e) {
4050 	if (UTF8SKIP(s) > len) {
4051 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
4052 			   "%s in %s", unees, PL_op ? OP_DESC(PL_op) : "print");
4053 	    return FALSE;
4054 	}
4055 	if (UNLIKELY(isUTF8_POSSIBLY_PROBLEMATIC(*s))) {
4056 	    STRLEN char_len;
4057 	    if (UTF8_IS_SUPER(s, e)) {
4058                 if (   ckWARN_d(WARN_NON_UNICODE)
4059                     || (   ckWARN_d(WARN_DEPRECATED)
4060 #if defined(UV_IS_QUAD)
4061                         /* 2**63 and up meet these conditions provided we have
4062                          * a 64-bit word. */
4063 #   ifdef EBCDIC
4064                         && *s == 0xFE && e - s >= UTF8_MAXBYTES
4065                         && s[1] >= 0x49
4066 #   else
4067                         && *s == 0xFF && e -s >= UTF8_MAXBYTES
4068                         && s[2] >= 0x88
4069 #   endif
4070 #else   /* Below is 32-bit words */
4071                         /* 2**31 and above meet these conditions on all EBCDIC
4072                          * pages recognized for 32-bit platforms */
4073 #   ifdef EBCDIC
4074                         && *s == 0xFE && e - s >= UTF8_MAXBYTES
4075                         && s[6] >= 0x43
4076 #   else
4077                         && *s >= 0xFE
4078 #   endif
4079 #endif
4080                 )) {
4081                     /* A side effect of this function will be to warn */
4082                     (void) utf8n_to_uvchr(s, e - s, &char_len, UTF8_WARN_SUPER);
4083                     ok = FALSE;
4084                 }
4085 	    }
4086 	    else if (UTF8_IS_SURROGATE(s, e)) {
4087 		if (ckWARN_d(WARN_SURROGATE)) {
4088                     /* This has a different warning than the one the called
4089                      * function would output, so can't just call it, unlike we
4090                      * do for the non-chars and above-unicodes */
4091 		    UV uv = utf8_to_uvchr_buf(s, e, &char_len);
4092 		    Perl_warner(aTHX_ packWARN(WARN_SURROGATE),
4093 			"Unicode surrogate U+%04"UVXf" is illegal in UTF-8", uv);
4094 		    ok = FALSE;
4095 		}
4096 	    }
4097 	    else if ((UTF8_IS_NONCHAR(s, e)) && (ckWARN_d(WARN_NONCHAR))) {
4098                 /* A side effect of this function will be to warn */
4099                 (void) utf8n_to_uvchr(s, e - s, &char_len, UTF8_WARN_NONCHAR);
4100 		ok = FALSE;
4101 	    }
4102 	}
4103 	s += UTF8SKIP(s);
4104     }
4105 
4106     return ok;
4107 }
4108 
4109 /*
4110 =for apidoc pv_uni_display
4111 
4112 Build to the scalar C<dsv> a displayable version of the string C<spv>,
4113 length C<len>, the displayable version being at most C<pvlim> bytes long
4114 (if longer, the rest is truncated and C<"..."> will be appended).
4115 
4116 The C<flags> argument can have C<UNI_DISPLAY_ISPRINT> set to display
4117 C<isPRINT()>able characters as themselves, C<UNI_DISPLAY_BACKSLASH>
4118 to display the C<\\[nrfta\\]> as the backslashed versions (like C<"\n">)
4119 (C<UNI_DISPLAY_BACKSLASH> is preferred over C<UNI_DISPLAY_ISPRINT> for C<"\\">).
4120 C<UNI_DISPLAY_QQ> (and its alias C<UNI_DISPLAY_REGEX>) have both
4121 C<UNI_DISPLAY_BACKSLASH> and C<UNI_DISPLAY_ISPRINT> turned on.
4122 
4123 The pointer to the PV of the C<dsv> is returned.
4124 
4125 See also L</sv_uni_display>.
4126 
4127 =cut */
4128 char *
4129 Perl_pv_uni_display(pTHX_ SV *dsv, const U8 *spv, STRLEN len, STRLEN pvlim, UV flags)
4130 {
4131     int truncated = 0;
4132     const char *s, *e;
4133 
4134     PERL_ARGS_ASSERT_PV_UNI_DISPLAY;
4135 
4136     sv_setpvs(dsv, "");
4137     SvUTF8_off(dsv);
4138     for (s = (const char *)spv, e = s + len; s < e; s += UTF8SKIP(s)) {
4139 	 UV u;
4140 	  /* This serves double duty as a flag and a character to print after
4141 	     a \ when flags & UNI_DISPLAY_BACKSLASH is true.
4142 	  */
4143 	 char ok = 0;
4144 
4145 	 if (pvlim && SvCUR(dsv) >= pvlim) {
4146 	      truncated++;
4147 	      break;
4148 	 }
4149 	 u = utf8_to_uvchr_buf((U8*)s, (U8*)e, 0);
4150 	 if (u < 256) {
4151 	     const unsigned char c = (unsigned char)u & 0xFF;
4152 	     if (flags & UNI_DISPLAY_BACKSLASH) {
4153 	         switch (c) {
4154 		 case '\n':
4155 		     ok = 'n'; break;
4156 		 case '\r':
4157 		     ok = 'r'; break;
4158 		 case '\t':
4159 		     ok = 't'; break;
4160 		 case '\f':
4161 		     ok = 'f'; break;
4162 		 case '\a':
4163 		     ok = 'a'; break;
4164 		 case '\\':
4165 		     ok = '\\'; break;
4166 		 default: break;
4167 		 }
4168 		 if (ok) {
4169 		     const char string = ok;
4170 		     sv_catpvs(dsv, "\\");
4171 		     sv_catpvn(dsv, &string, 1);
4172 		 }
4173 	     }
4174 	     /* isPRINT() is the locale-blind version. */
4175 	     if (!ok && (flags & UNI_DISPLAY_ISPRINT) && isPRINT(c)) {
4176 		 const char string = c;
4177 		 sv_catpvn(dsv, &string, 1);
4178 		 ok = 1;
4179 	     }
4180 	 }
4181 	 if (!ok)
4182 	     Perl_sv_catpvf(aTHX_ dsv, "\\x{%"UVxf"}", u);
4183     }
4184     if (truncated)
4185 	 sv_catpvs(dsv, "...");
4186 
4187     return SvPVX(dsv);
4188 }
4189 
4190 /*
4191 =for apidoc sv_uni_display
4192 
4193 Build to the scalar C<dsv> a displayable version of the scalar C<sv>,
4194 the displayable version being at most C<pvlim> bytes long
4195 (if longer, the rest is truncated and "..." will be appended).
4196 
4197 The C<flags> argument is as in L</pv_uni_display>().
4198 
4199 The pointer to the PV of the C<dsv> is returned.
4200 
4201 =cut
4202 */
4203 char *
4204 Perl_sv_uni_display(pTHX_ SV *dsv, SV *ssv, STRLEN pvlim, UV flags)
4205 {
4206     const char * const ptr =
4207         isREGEXP(ssv) ? RX_WRAPPED((REGEXP*)ssv) : SvPVX_const(ssv);
4208 
4209     PERL_ARGS_ASSERT_SV_UNI_DISPLAY;
4210 
4211     return Perl_pv_uni_display(aTHX_ dsv, (const U8*)ptr,
4212 				SvCUR(ssv), pvlim, flags);
4213 }
4214 
4215 /*
4216 =for apidoc foldEQ_utf8
4217 
4218 Returns true if the leading portions of the strings C<s1> and C<s2> (either or both
4219 of which may be in UTF-8) are the same case-insensitively; false otherwise.
4220 How far into the strings to compare is determined by other input parameters.
4221 
4222 If C<u1> is true, the string C<s1> is assumed to be in UTF-8-encoded Unicode;
4223 otherwise it is assumed to be in native 8-bit encoding.  Correspondingly for C<u2>
4224 with respect to C<s2>.
4225 
4226 If the byte length C<l1> is non-zero, it says how far into C<s1> to check for fold
4227 equality.  In other words, C<s1>+C<l1> will be used as a goal to reach.  The
4228 scan will not be considered to be a match unless the goal is reached, and
4229 scanning won't continue past that goal.  Correspondingly for C<l2> with respect to
4230 C<s2>.
4231 
4232 If C<pe1> is non-C<NULL> and the pointer it points to is not C<NULL>, that pointer is
4233 considered an end pointer to the position 1 byte past the maximum point
4234 in C<s1> beyond which scanning will not continue under any circumstances.
4235 (This routine assumes that UTF-8 encoded input strings are not malformed;
4236 malformed input can cause it to read past C<pe1>).
4237 This means that if both C<l1> and C<pe1> are specified, and C<pe1>
4238 is less than C<s1>+C<l1>, the match will never be successful because it can
4239 never
4240 get as far as its goal (and in fact is asserted against).  Correspondingly for
4241 C<pe2> with respect to C<s2>.
4242 
4243 At least one of C<s1> and C<s2> must have a goal (at least one of C<l1> and
4244 C<l2> must be non-zero), and if both do, both have to be
4245 reached for a successful match.   Also, if the fold of a character is multiple
4246 characters, all of them must be matched (see tr21 reference below for
4247 'folding').
4248 
4249 Upon a successful match, if C<pe1> is non-C<NULL>,
4250 it will be set to point to the beginning of the I<next> character of C<s1>
4251 beyond what was matched.  Correspondingly for C<pe2> and C<s2>.
4252 
4253 For case-insensitiveness, the "casefolding" of Unicode is used
4254 instead of upper/lowercasing both the characters, see
4255 L<http://www.unicode.org/unicode/reports/tr21/> (Case Mappings).
4256 
4257 =cut */
4258 
4259 /* A flags parameter has been added which may change, and hence isn't
4260  * externally documented.  Currently it is:
4261  *  0 for as-documented above
4262  *  FOLDEQ_UTF8_NOMIX_ASCII meaning that if a non-ASCII character folds to an
4263 			    ASCII one, to not match
4264  *  FOLDEQ_LOCALE	    is set iff the rules from the current underlying
4265  *	                    locale are to be used.
4266  *  FOLDEQ_S1_ALREADY_FOLDED  s1 has already been folded before calling this
4267  *                          routine.  This allows that step to be skipped.
4268  *                          Currently, this requires s1 to be encoded as UTF-8
4269  *                          (u1 must be true), which is asserted for.
4270  *  FOLDEQ_S1_FOLDS_SANE    With either NOMIX_ASCII or LOCALE, no folds may
4271  *                          cross certain boundaries.  Hence, the caller should
4272  *                          let this function do the folding instead of
4273  *                          pre-folding.  This code contains an assertion to
4274  *                          that effect.  However, if the caller knows what
4275  *                          it's doing, it can pass this flag to indicate that,
4276  *                          and the assertion is skipped.
4277  *  FOLDEQ_S2_ALREADY_FOLDED  Similarly.
4278  *  FOLDEQ_S2_FOLDS_SANE
4279  */
4280 I32
4281 Perl_foldEQ_utf8_flags(pTHX_ const char *s1, char **pe1, UV l1, bool u1, const char *s2, char **pe2, UV l2, bool u2, U32 flags)
4282 {
4283     const U8 *p1  = (const U8*)s1; /* Point to current char */
4284     const U8 *p2  = (const U8*)s2;
4285     const U8 *g1 = NULL;       /* goal for s1 */
4286     const U8 *g2 = NULL;
4287     const U8 *e1 = NULL;       /* Don't scan s1 past this */
4288     U8 *f1 = NULL;             /* Point to current folded */
4289     const U8 *e2 = NULL;
4290     U8 *f2 = NULL;
4291     STRLEN n1 = 0, n2 = 0;              /* Number of bytes in current char */
4292     U8 foldbuf1[UTF8_MAXBYTES_CASE+1];
4293     U8 foldbuf2[UTF8_MAXBYTES_CASE+1];
4294     U8 flags_for_folder = FOLD_FLAGS_FULL;
4295 
4296     PERL_ARGS_ASSERT_FOLDEQ_UTF8_FLAGS;
4297 
4298     assert( ! ((flags & (FOLDEQ_UTF8_NOMIX_ASCII | FOLDEQ_LOCALE))
4299                && (((flags & FOLDEQ_S1_ALREADY_FOLDED)
4300                      && !(flags & FOLDEQ_S1_FOLDS_SANE))
4301                    || ((flags & FOLDEQ_S2_ALREADY_FOLDED)
4302                        && !(flags & FOLDEQ_S2_FOLDS_SANE)))));
4303     /* The algorithm is to trial the folds without regard to the flags on
4304      * the first line of the above assert(), and then see if the result
4305      * violates them.  This means that the inputs can't be pre-folded to a
4306      * violating result, hence the assert.  This could be changed, with the
4307      * addition of extra tests here for the already-folded case, which would
4308      * slow it down.  That cost is more than any possible gain for when these
4309      * flags are specified, as the flags indicate /il or /iaa matching which
4310      * is less common than /iu, and I (khw) also believe that real-world /il
4311      * and /iaa matches are most likely to involve code points 0-255, and this
4312      * function only under rare conditions gets called for 0-255. */
4313 
4314     if (flags & FOLDEQ_LOCALE) {
4315         if (IN_UTF8_CTYPE_LOCALE) {
4316             flags &= ~FOLDEQ_LOCALE;
4317         }
4318         else {
4319             flags_for_folder |= FOLD_FLAGS_LOCALE;
4320         }
4321     }
4322 
4323     if (pe1) {
4324         e1 = *(U8**)pe1;
4325     }
4326 
4327     if (l1) {
4328         g1 = (const U8*)s1 + l1;
4329     }
4330 
4331     if (pe2) {
4332         e2 = *(U8**)pe2;
4333     }
4334 
4335     if (l2) {
4336         g2 = (const U8*)s2 + l2;
4337     }
4338 
4339     /* Must have at least one goal */
4340     assert(g1 || g2);
4341 
4342     if (g1) {
4343 
4344         /* Will never match if goal is out-of-bounds */
4345         assert(! e1  || e1 >= g1);
4346 
4347         /* Here, there isn't an end pointer, or it is beyond the goal.  We
4348         * only go as far as the goal */
4349         e1 = g1;
4350     }
4351     else {
4352 	assert(e1);    /* Must have an end for looking at s1 */
4353     }
4354 
4355     /* Same for goal for s2 */
4356     if (g2) {
4357         assert(! e2  || e2 >= g2);
4358         e2 = g2;
4359     }
4360     else {
4361 	assert(e2);
4362     }
4363 
4364     /* If both operands are already folded, we could just do a memEQ on the
4365      * whole strings at once, but it would be better if the caller realized
4366      * this and didn't even call us */
4367 
4368     /* Look through both strings, a character at a time */
4369     while (p1 < e1 && p2 < e2) {
4370 
4371         /* If at the beginning of a new character in s1, get its fold to use
4372 	 * and the length of the fold. */
4373         if (n1 == 0) {
4374 	    if (flags & FOLDEQ_S1_ALREADY_FOLDED) {
4375 		f1 = (U8 *) p1;
4376                 assert(u1);
4377 		n1 = UTF8SKIP(f1);
4378 	    }
4379 	    else {
4380                 if (isASCII(*p1) && ! (flags & FOLDEQ_LOCALE)) {
4381 
4382                     /* We have to forbid mixing ASCII with non-ASCII if the
4383                      * flags so indicate.  And, we can short circuit having to
4384                      * call the general functions for this common ASCII case,
4385                      * all of whose non-locale folds are also ASCII, and hence
4386                      * UTF-8 invariants, so the UTF8ness of the strings is not
4387                      * relevant. */
4388                     if ((flags & FOLDEQ_UTF8_NOMIX_ASCII) && ! isASCII(*p2)) {
4389                         return 0;
4390                     }
4391                     n1 = 1;
4392                     *foldbuf1 = toFOLD(*p1);
4393                 }
4394                 else if (u1) {
4395                     _to_utf8_fold_flags(p1, foldbuf1, &n1, flags_for_folder);
4396                 }
4397                 else {  /* Not UTF-8, get UTF-8 fold */
4398                     _to_uni_fold_flags(*p1, foldbuf1, &n1, flags_for_folder);
4399                 }
4400                 f1 = foldbuf1;
4401             }
4402         }
4403 
4404         if (n2 == 0) {    /* Same for s2 */
4405 	    if (flags & FOLDEQ_S2_ALREADY_FOLDED) {
4406 		f2 = (U8 *) p2;
4407                 assert(u2);
4408 		n2 = UTF8SKIP(f2);
4409 	    }
4410 	    else {
4411                 if (isASCII(*p2) && ! (flags & FOLDEQ_LOCALE)) {
4412                     if ((flags & FOLDEQ_UTF8_NOMIX_ASCII) && ! isASCII(*p1)) {
4413                         return 0;
4414                     }
4415                     n2 = 1;
4416                     *foldbuf2 = toFOLD(*p2);
4417                 }
4418                 else if (u2) {
4419                     _to_utf8_fold_flags(p2, foldbuf2, &n2, flags_for_folder);
4420                 }
4421                 else {
4422                     _to_uni_fold_flags(*p2, foldbuf2, &n2, flags_for_folder);
4423                 }
4424                 f2 = foldbuf2;
4425 	    }
4426         }
4427 
4428 	/* Here f1 and f2 point to the beginning of the strings to compare.
4429 	 * These strings are the folds of the next character from each input
4430 	 * string, stored in UTF-8. */
4431 
4432         /* While there is more to look for in both folds, see if they
4433         * continue to match */
4434         while (n1 && n2) {
4435             U8 fold_length = UTF8SKIP(f1);
4436             if (fold_length != UTF8SKIP(f2)
4437                 || (fold_length == 1 && *f1 != *f2) /* Short circuit memNE
4438                                                        function call for single
4439                                                        byte */
4440                 || memNE((char*)f1, (char*)f2, fold_length))
4441             {
4442                 return 0; /* mismatch */
4443             }
4444 
4445             /* Here, they matched, advance past them */
4446             n1 -= fold_length;
4447             f1 += fold_length;
4448             n2 -= fold_length;
4449             f2 += fold_length;
4450         }
4451 
4452         /* When reach the end of any fold, advance the input past it */
4453         if (n1 == 0) {
4454             p1 += u1 ? UTF8SKIP(p1) : 1;
4455         }
4456         if (n2 == 0) {
4457             p2 += u2 ? UTF8SKIP(p2) : 1;
4458         }
4459     } /* End of loop through both strings */
4460 
4461     /* A match is defined by each scan that specified an explicit length
4462     * reaching its final goal, and the other not having matched a partial
4463     * character (which can happen when the fold of a character is more than one
4464     * character). */
4465     if (! ((g1 == 0 || p1 == g1) && (g2 == 0 || p2 == g2)) || n1 || n2) {
4466         return 0;
4467     }
4468 
4469     /* Successful match.  Set output pointers */
4470     if (pe1) {
4471         *pe1 = (char*)p1;
4472     }
4473     if (pe2) {
4474         *pe2 = (char*)p2;
4475     }
4476     return 1;
4477 }
4478 
4479 /* XXX The next two functions should likely be moved to mathoms.c once all
4480  * occurrences of them are removed from the core; some cpan-upstream modules
4481  * still use them */
4482 
4483 U8 *
4484 Perl_uvuni_to_utf8(pTHX_ U8 *d, UV uv)
4485 {
4486     PERL_ARGS_ASSERT_UVUNI_TO_UTF8;
4487 
4488     return Perl_uvoffuni_to_utf8_flags(aTHX_ d, uv, 0);
4489 }
4490 
4491 /*
4492 =for apidoc utf8n_to_uvuni
4493 
4494 Instead use L</utf8_to_uvchr_buf>, or rarely, L</utf8n_to_uvchr>.
4495 
4496 This function was useful for code that wanted to handle both EBCDIC and
4497 ASCII platforms with Unicode properties, but starting in Perl v5.20, the
4498 distinctions between the platforms have mostly been made invisible to most
4499 code, so this function is quite unlikely to be what you want.  If you do need
4500 this precise functionality, use instead
4501 C<L<NATIVE_TO_UNI(utf8_to_uvchr_buf(...))|/utf8_to_uvchr_buf>>
4502 or C<L<NATIVE_TO_UNI(utf8n_to_uvchr(...))|/utf8n_to_uvchr>>.
4503 
4504 =cut
4505 */
4506 
4507 UV
4508 Perl_utf8n_to_uvuni(pTHX_ const U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
4509 {
4510     PERL_ARGS_ASSERT_UTF8N_TO_UVUNI;
4511 
4512     return NATIVE_TO_UNI(utf8n_to_uvchr(s, curlen, retlen, flags));
4513 }
4514 
4515 /*
4516 =for apidoc uvuni_to_utf8_flags
4517 
4518 Instead you almost certainly want to use L</uvchr_to_utf8> or
4519 L</uvchr_to_utf8_flags>.
4520 
4521 This function is a deprecated synonym for L</uvoffuni_to_utf8_flags>,
4522 which itself, while not deprecated, should be used only in isolated
4523 circumstances.  These functions were useful for code that wanted to handle
4524 both EBCDIC and ASCII platforms with Unicode properties, but starting in Perl
4525 v5.20, the distinctions between the platforms have mostly been made invisible
4526 to most code, so this function is quite unlikely to be what you want.
4527 
4528 =cut
4529 */
4530 
4531 U8 *
4532 Perl_uvuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
4533 {
4534     PERL_ARGS_ASSERT_UVUNI_TO_UTF8_FLAGS;
4535 
4536     return uvoffuni_to_utf8_flags(d, uv, flags);
4537 }
4538 
4539 /*
4540  * ex: set ts=8 sts=4 sw=4 et:
4541  */
4542