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 malformed_text[] = "Malformed UTF-8 character";
37 static const char unees[] =
38                         "Malformed UTF-8 character (unexpected end of string)";
39 
40 /* Be sure to synchronize this message with the similar one in regcomp.c */
41 static const char cp_above_legal_max[] =
42                         "Use of code point 0x%" UVXf " is not allowed; the"
43                         " permissible max is 0x%" UVXf;
44 
45 /*
46 =head1 Unicode Support
47 These are various utility functions for manipulating UTF8-encoded
48 strings.  For the uninitiated, this is a method of representing arbitrary
49 Unicode characters as a variable number of bytes, in such a way that
50 characters in the ASCII range are unmodified, and a zero byte never appears
51 within non-zero characters.
52 
53 =cut
54 */
55 
56 /* helper for Perl__force_out_malformed_utf8_message(). Like
57  * SAVECOMPILEWARNINGS(), but works with PL_curcop rather than
58  * PL_compiling */
59 
60 static void
S_restore_cop_warnings(pTHX_ void * p)61 S_restore_cop_warnings(pTHX_ void *p)
62 {
63     if (!specialWARN(PL_curcop->cop_warnings))
64         PerlMemShared_free(PL_curcop->cop_warnings);
65     PL_curcop->cop_warnings = (STRLEN*)p;
66 }
67 
68 
69 void
Perl__force_out_malformed_utf8_message(pTHX_ const U8 * const p,const U8 * const e,const U32 flags,const bool die_here)70 Perl__force_out_malformed_utf8_message(pTHX_
71             const U8 *const p,      /* First byte in UTF-8 sequence */
72             const U8 * const e,     /* Final byte in sequence (may include
73                                        multiple chars */
74             const U32 flags,        /* Flags to pass to utf8n_to_uvchr(),
75                                        usually 0, or some DISALLOW flags */
76             const bool die_here)    /* If TRUE, this function does not return */
77 {
78     /* This core-only function is to be called when a malformed UTF-8 character
79      * is found, in order to output the detailed information about the
80      * malformation before dieing.  The reason it exists is for the occasions
81      * when such a malformation is fatal, but warnings might be turned off, so
82      * that normally they would not be actually output.  This ensures that they
83      * do get output.  Because a sequence may be malformed in more than one
84      * way, multiple messages may be generated, so we can't make them fatal, as
85      * that would cause the first one to die.
86      *
87      * Instead we pretend -W was passed to perl, then die afterwards.  The
88      * flexibility is here to return to the caller so they can finish up and
89      * die themselves */
90     U32 errors;
91 
92     PERL_ARGS_ASSERT__FORCE_OUT_MALFORMED_UTF8_MESSAGE;
93 
94     ENTER;
95     SAVEI8(PL_dowarn);
96     SAVESPTR(PL_curcop);
97 
98     PL_dowarn = G_WARN_ALL_ON|G_WARN_ON;
99     if (PL_curcop) {
100         /* this is like SAVECOMPILEWARNINGS() except with PL_curcop rather
101          * than PL_compiling */
102         SAVEDESTRUCTOR_X(S_restore_cop_warnings,
103                 (void*)PL_curcop->cop_warnings);
104         PL_curcop->cop_warnings = pWARN_ALL;
105     }
106 
107     (void) utf8n_to_uvchr_error(p, e - p, NULL, flags & ~UTF8_CHECK_ONLY, &errors);
108 
109     LEAVE;
110 
111     if (! errors) {
112 	Perl_croak(aTHX_ "panic: _force_out_malformed_utf8_message should"
113                          " be called only when there are errors found");
114     }
115 
116     if (die_here) {
117         Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
118     }
119 }
120 
121 STATIC HV *
S_new_msg_hv(pTHX_ const char * const message,U32 categories,U32 flag)122 S_new_msg_hv(pTHX_ const char * const message, /* The message text */
123                    U32 categories,  /* Packed warning categories */
124                    U32 flag)        /* Flag associated with this message */
125 {
126     /* Creates, populates, and returns an HV* that describes an error message
127      * for the translators between UTF8 and code point */
128 
129     SV* msg_sv = newSVpv(message, 0);
130     SV* category_sv = newSVuv(categories);
131     SV* flag_bit_sv = newSVuv(flag);
132 
133     HV* msg_hv = newHV();
134 
135     PERL_ARGS_ASSERT_NEW_MSG_HV;
136 
137     (void) hv_stores(msg_hv, "text", msg_sv);
138     (void) hv_stores(msg_hv, "warn_categories",  category_sv);
139     (void) hv_stores(msg_hv, "flag_bit", flag_bit_sv);
140 
141     return msg_hv;
142 }
143 
144 /*
145 =for apidoc uvoffuni_to_utf8_flags
146 
147 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
148 Instead, B<Almost all code should use L</uvchr_to_utf8> or
149 L</uvchr_to_utf8_flags>>.
150 
151 This function is like them, but the input is a strict Unicode
152 (as opposed to native) code point.  Only in very rare circumstances should code
153 not be using the native code point.
154 
155 For details, see the description for L</uvchr_to_utf8_flags>.
156 
157 =cut
158 */
159 
160 U8 *
Perl_uvoffuni_to_utf8_flags(pTHX_ U8 * d,UV uv,const UV flags)161 Perl_uvoffuni_to_utf8_flags(pTHX_ U8 *d, UV uv, const UV flags)
162 {
163     PERL_ARGS_ASSERT_UVOFFUNI_TO_UTF8_FLAGS;
164 
165     return uvoffuni_to_utf8_flags_msgs(d, uv, flags, NULL);
166 }
167 
168 /* All these formats take a single UV code point argument */
169 const char surrogate_cp_format[] = "UTF-16 surrogate U+%04" UVXf;
170 const char nonchar_cp_format[]   = "Unicode non-character U+%04" UVXf
171                                    " is not recommended for open interchange";
172 const char super_cp_format[]     = "Code point 0x%" UVXf " is not Unicode,"
173                                    " may not be portable";
174 const char perl_extended_cp_format[] = "Code point 0x%" UVXf " is not"        \
175                                        " Unicode, requires a Perl extension," \
176                                        " and so is not portable";
177 
178 #define HANDLE_UNICODE_SURROGATE(uv, flags, msgs)                   \
179     STMT_START {                                                    \
180         if (flags & UNICODE_WARN_SURROGATE) {                       \
181             U32 category = packWARN(WARN_SURROGATE);                \
182             const char * format = surrogate_cp_format;              \
183             if (msgs) {                                             \
184                 *msgs = new_msg_hv(Perl_form(aTHX_ format, uv),     \
185                                    category,                        \
186                                    UNICODE_GOT_SURROGATE);          \
187             }                                                       \
188             else {                                                  \
189                 Perl_ck_warner_d(aTHX_ category, format, uv);       \
190             }                                                       \
191         }                                                           \
192         if (flags & UNICODE_DISALLOW_SURROGATE) {                   \
193             return NULL;                                            \
194         }                                                           \
195     } STMT_END;
196 
197 #define HANDLE_UNICODE_NONCHAR(uv, flags, msgs)                     \
198     STMT_START {                                                    \
199         if (flags & UNICODE_WARN_NONCHAR) {                         \
200             U32 category = packWARN(WARN_NONCHAR);                  \
201             const char * format = nonchar_cp_format;                \
202             if (msgs) {                                             \
203                 *msgs = new_msg_hv(Perl_form(aTHX_ format, uv),     \
204                                    category,                        \
205                                    UNICODE_GOT_NONCHAR);            \
206             }                                                       \
207             else {                                                  \
208                 Perl_ck_warner_d(aTHX_ category, format, uv);       \
209             }                                                       \
210         }                                                           \
211         if (flags & UNICODE_DISALLOW_NONCHAR) {                     \
212             return NULL;                                            \
213         }                                                           \
214     } STMT_END;
215 
216 /*  Use shorter names internally in this file */
217 #define SHIFT   UTF_ACCUMULATION_SHIFT
218 #undef  MARK
219 #define MARK    UTF_CONTINUATION_MARK
220 #define MASK    UTF_CONTINUATION_MASK
221 
222 /*
223 =for apidoc uvchr_to_utf8_flags_msgs
224 
225 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
226 
227 Most code should use C<L</uvchr_to_utf8_flags>()> rather than call this directly.
228 
229 This function is for code that wants any warning and/or error messages to be
230 returned to the caller rather than be displayed.  All messages that would have
231 been displayed if all lexical warnings are enabled will be returned.
232 
233 It is just like C<L</uvchr_to_utf8_flags>> but it takes an extra parameter
234 placed after all the others, C<msgs>.  If this parameter is 0, this function
235 behaves identically to C<L</uvchr_to_utf8_flags>>.  Otherwise, C<msgs> should
236 be a pointer to an C<HV *> variable, in which this function creates a new HV to
237 contain any appropriate messages.  The hash has three key-value pairs, as
238 follows:
239 
240 =over 4
241 
242 =item C<text>
243 
244 The text of the message as a C<SVpv>.
245 
246 =item C<warn_categories>
247 
248 The warning category (or categories) packed into a C<SVuv>.
249 
250 =item C<flag>
251 
252 A single flag bit associated with this message, in a C<SVuv>.
253 The bit corresponds to some bit in the C<*errors> return value,
254 such as C<UNICODE_GOT_SURROGATE>.
255 
256 =back
257 
258 It's important to note that specifying this parameter as non-null will cause
259 any warnings this function would otherwise generate to be suppressed, and
260 instead be placed in C<*msgs>.  The caller can check the lexical warnings state
261 (or not) when choosing what to do with the returned messages.
262 
263 The caller, of course, is responsible for freeing any returned HV.
264 
265 =cut
266 */
267 
268 /* Undocumented; we don't want people using this.  Instead they should use
269  * uvchr_to_utf8_flags_msgs() */
270 U8 *
Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 * d,UV uv,const UV flags,HV ** msgs)271 Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 *d, UV uv, const UV flags, HV** msgs)
272 {
273     PERL_ARGS_ASSERT_UVOFFUNI_TO_UTF8_FLAGS_MSGS;
274 
275     if (msgs) {
276         *msgs = NULL;
277     }
278 
279     if (OFFUNI_IS_INVARIANT(uv)) {
280 	*d++ = LATIN1_TO_NATIVE(uv);
281 	return d;
282     }
283 
284     if (uv <= MAX_UTF8_TWO_BYTE) {
285         *d++ = I8_TO_NATIVE_UTF8(( uv >> SHIFT) | UTF_START_MARK(2));
286         *d++ = I8_TO_NATIVE_UTF8(( uv           & MASK) |   MARK);
287         return d;
288     }
289 
290     /* Not 2-byte; test for and handle 3-byte result.   In the test immediately
291      * below, the 16 is for start bytes E0-EF (which are all the possible ones
292      * for 3 byte characters).  The 2 is for 2 continuation bytes; these each
293      * contribute SHIFT bits.  This yields 0x4000 on EBCDIC platforms, 0x1_0000
294      * on ASCII; so 3 bytes covers the range 0x400-0x3FFF on EBCDIC;
295      * 0x800-0xFFFF on ASCII */
296     if (uv < (16 * (1U << (2 * SHIFT)))) {
297 	*d++ = I8_TO_NATIVE_UTF8(( uv >> ((3 - 1) * SHIFT)) | UTF_START_MARK(3));
298 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((2 - 1) * SHIFT)) & MASK) |   MARK);
299 	*d++ = I8_TO_NATIVE_UTF8(( uv  /* (1 - 1) */        & MASK) |   MARK);
300 
301 #ifndef EBCDIC  /* These problematic code points are 4 bytes on EBCDIC, so
302                    aren't tested here */
303         /* The most likely code points in this range are below the surrogates.
304          * Do an extra test to quickly exclude those. */
305         if (UNLIKELY(uv >= UNICODE_SURROGATE_FIRST)) {
306             if (UNLIKELY(   UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv)
307                          || UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv)))
308             {
309                 HANDLE_UNICODE_NONCHAR(uv, flags, msgs);
310             }
311             else if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
312                 HANDLE_UNICODE_SURROGATE(uv, flags, msgs);
313             }
314         }
315 #endif
316 	return d;
317     }
318 
319     /* Not 3-byte; that means the code point is at least 0x1_0000 on ASCII
320      * platforms, and 0x4000 on EBCDIC.  There are problematic cases that can
321      * happen starting with 4-byte characters on ASCII platforms.  We unify the
322      * code for these with EBCDIC, even though some of them require 5-bytes on
323      * those, because khw believes the code saving is worth the very slight
324      * performance hit on these high EBCDIC code points. */
325 
326     if (UNLIKELY(UNICODE_IS_SUPER(uv))) {
327         if (UNLIKELY(uv > MAX_LEGAL_CP)) {
328             Perl_croak(aTHX_ cp_above_legal_max, uv, MAX_LEGAL_CP);
329         }
330         if (       (flags & UNICODE_WARN_SUPER)
331             || (   (flags & UNICODE_WARN_PERL_EXTENDED)
332                 && UNICODE_IS_PERL_EXTENDED(uv)))
333         {
334             const char * format = super_cp_format;
335             U32 category = packWARN(WARN_NON_UNICODE);
336             U32 flag = UNICODE_GOT_SUPER;
337 
338             /* Choose the more dire applicable warning */
339             if (UNICODE_IS_PERL_EXTENDED(uv)) {
340                 format = perl_extended_cp_format;
341                 if (flags & (UNICODE_WARN_PERL_EXTENDED
342                             |UNICODE_DISALLOW_PERL_EXTENDED))
343                 {
344                     flag = UNICODE_GOT_PERL_EXTENDED;
345                 }
346             }
347 
348             if (msgs) {
349                 *msgs = new_msg_hv(Perl_form(aTHX_ format, uv),
350                                    category, flag);
351             }
352             else {
353                 Perl_ck_warner_d(aTHX_ packWARN(WARN_NON_UNICODE), format, uv);
354             }
355         }
356         if (       (flags & UNICODE_DISALLOW_SUPER)
357             || (   (flags & UNICODE_DISALLOW_PERL_EXTENDED)
358                 &&  UNICODE_IS_PERL_EXTENDED(uv)))
359         {
360             return NULL;
361         }
362     }
363     else if (UNLIKELY(UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv))) {
364         HANDLE_UNICODE_NONCHAR(uv, flags, msgs);
365     }
366 
367     /* Test for and handle 4-byte result.   In the test immediately below, the
368      * 8 is for start bytes F0-F7 (which are all the possible ones for 4 byte
369      * characters).  The 3 is for 3 continuation bytes; these each contribute
370      * SHIFT bits.  This yields 0x4_0000 on EBCDIC platforms, 0x20_0000 on
371      * ASCII, so 4 bytes covers the range 0x4000-0x3_FFFF on EBCDIC;
372      * 0x1_0000-0x1F_FFFF on ASCII */
373     if (uv < (8 * (1U << (3 * SHIFT)))) {
374 	*d++ = I8_TO_NATIVE_UTF8(( uv >> ((4 - 1) * SHIFT)) | UTF_START_MARK(4));
375 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((3 - 1) * SHIFT)) & MASK) |   MARK);
376 	*d++ = I8_TO_NATIVE_UTF8(((uv >> ((2 - 1) * SHIFT)) & MASK) |   MARK);
377 	*d++ = I8_TO_NATIVE_UTF8(( uv  /* (1 - 1) */        & MASK) |   MARK);
378 
379 #ifdef EBCDIC   /* These were handled on ASCII platforms in the code for 3-byte
380                    characters.  The end-plane non-characters for EBCDIC were
381                    handled just above */
382         if (UNLIKELY(UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv))) {
383             HANDLE_UNICODE_NONCHAR(uv, flags, msgs);
384         }
385         else if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
386             HANDLE_UNICODE_SURROGATE(uv, flags, msgs);
387         }
388 #endif
389 
390 	return d;
391     }
392 
393     /* Not 4-byte; that means the code point is at least 0x20_0000 on ASCII
394      * platforms, and 0x4000 on EBCDIC.  At this point we switch to a loop
395      * format.  The unrolled version above turns out to not save all that much
396      * time, and at these high code points (well above the legal Unicode range
397      * on ASCII platforms, and well above anything in common use in EBCDIC),
398      * khw believes that less code outweighs slight performance gains. */
399 
400     {
401 	STRLEN len  = OFFUNISKIP(uv);
402 	U8 *p = d+len-1;
403 	while (p > d) {
404 	    *p-- = I8_TO_NATIVE_UTF8((uv & MASK) | MARK);
405 	    uv >>= SHIFT;
406 	}
407 	*p = I8_TO_NATIVE_UTF8((uv & UTF_START_MASK(len)) | UTF_START_MARK(len));
408 	return d+len;
409     }
410 }
411 
412 /*
413 =for apidoc uvchr_to_utf8
414 
415 Adds the UTF-8 representation of the native code point C<uv> to the end
416 of the string C<d>; C<d> should have at least C<UVCHR_SKIP(uv)+1> (up to
417 C<UTF8_MAXBYTES+1>) free bytes available.  The return value is the pointer to
418 the byte after the end of the new character.  In other words,
419 
420     d = uvchr_to_utf8(d, uv);
421 
422 is the recommended wide native character-aware way of saying
423 
424     *(d++) = uv;
425 
426 This function accepts any code point from 0..C<IV_MAX> as input.
427 C<IV_MAX> is typically 0x7FFF_FFFF in a 32-bit word.
428 
429 It is possible to forbid or warn on non-Unicode code points, or those that may
430 be problematic by using L</uvchr_to_utf8_flags>.
431 
432 =cut
433 */
434 
435 /* This is also a macro */
436 PERL_CALLCONV U8*       Perl_uvchr_to_utf8(pTHX_ U8 *d, UV uv);
437 
438 U8 *
Perl_uvchr_to_utf8(pTHX_ U8 * d,UV uv)439 Perl_uvchr_to_utf8(pTHX_ U8 *d, UV uv)
440 {
441     return uvchr_to_utf8(d, uv);
442 }
443 
444 /*
445 =for apidoc uvchr_to_utf8_flags
446 
447 Adds the UTF-8 representation of the native code point C<uv> to the end
448 of the string C<d>; C<d> should have at least C<UVCHR_SKIP(uv)+1> (up to
449 C<UTF8_MAXBYTES+1>) free bytes available.  The return value is the pointer to
450 the byte after the end of the new character.  In other words,
451 
452     d = uvchr_to_utf8_flags(d, uv, flags);
453 
454 or, in most cases,
455 
456     d = uvchr_to_utf8_flags(d, uv, 0);
457 
458 This is the Unicode-aware way of saying
459 
460     *(d++) = uv;
461 
462 If C<flags> is 0, this function accepts any code point from 0..C<IV_MAX> as
463 input.  C<IV_MAX> is typically 0x7FFF_FFFF in a 32-bit word.
464 
465 Specifying C<flags> can further restrict what is allowed and not warned on, as
466 follows:
467 
468 If C<uv> is a Unicode surrogate code point and C<UNICODE_WARN_SURROGATE> is set,
469 the function will raise a warning, provided UTF8 warnings are enabled.  If
470 instead C<UNICODE_DISALLOW_SURROGATE> is set, the function will fail and return
471 NULL.  If both flags are set, the function will both warn and return NULL.
472 
473 Similarly, the C<UNICODE_WARN_NONCHAR> and C<UNICODE_DISALLOW_NONCHAR> flags
474 affect how the function handles a Unicode non-character.
475 
476 And likewise, the C<UNICODE_WARN_SUPER> and C<UNICODE_DISALLOW_SUPER> flags
477 affect the handling of code points that are above the Unicode maximum of
478 0x10FFFF.  Languages other than Perl may not be able to accept files that
479 contain these.
480 
481 The flag C<UNICODE_WARN_ILLEGAL_INTERCHANGE> selects all three of
482 the above WARN flags; and C<UNICODE_DISALLOW_ILLEGAL_INTERCHANGE> selects all
483 three DISALLOW flags.  C<UNICODE_DISALLOW_ILLEGAL_INTERCHANGE> restricts the
484 allowed inputs to the strict UTF-8 traditionally defined by Unicode.
485 Similarly, C<UNICODE_WARN_ILLEGAL_C9_INTERCHANGE> and
486 C<UNICODE_DISALLOW_ILLEGAL_C9_INTERCHANGE> are shortcuts to select the
487 above-Unicode and surrogate flags, but not the non-character ones, as
488 defined in
489 L<Unicode Corrigendum #9|http://www.unicode.org/versions/corrigendum9.html>.
490 See L<perlunicode/Noncharacter code points>.
491 
492 Extremely high code points were never specified in any standard, and require an
493 extension to UTF-8 to express, which Perl does.  It is likely that programs
494 written in something other than Perl would not be able to read files that
495 contain these; nor would Perl understand files written by something that uses a
496 different extension.  For these reasons, there is a separate set of flags that
497 can warn and/or disallow these extremely high code points, even if other
498 above-Unicode ones are accepted.  They are the C<UNICODE_WARN_PERL_EXTENDED>
499 and C<UNICODE_DISALLOW_PERL_EXTENDED> flags.  For more information see
500 L</C<UTF8_GOT_PERL_EXTENDED>>.  Of course C<UNICODE_DISALLOW_SUPER> will
501 treat all above-Unicode code points, including these, as malformations.  (Note
502 that the Unicode standard considers anything above 0x10FFFF to be illegal, but
503 there are standards predating it that allow up to 0x7FFF_FFFF (2**31 -1))
504 
505 A somewhat misleadingly named synonym for C<UNICODE_WARN_PERL_EXTENDED> is
506 retained for backward compatibility: C<UNICODE_WARN_ABOVE_31_BIT>.  Similarly,
507 C<UNICODE_DISALLOW_ABOVE_31_BIT> is usable instead of the more accurately named
508 C<UNICODE_DISALLOW_PERL_EXTENDED>.  The names are misleading because on EBCDIC
509 platforms,these flags can apply to code points that actually do fit in 31 bits.
510 The new names accurately describe the situation in all cases.
511 
512 =cut
513 */
514 
515 /* This is also a macro */
516 PERL_CALLCONV U8*       Perl_uvchr_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags);
517 
518 U8 *
Perl_uvchr_to_utf8_flags(pTHX_ U8 * d,UV uv,UV flags)519 Perl_uvchr_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
520 {
521     return uvchr_to_utf8_flags(d, uv, flags);
522 }
523 
524 #ifndef UV_IS_QUAD
525 
526 STATIC int
S_is_utf8_cp_above_31_bits(const U8 * const s,const U8 * const e,const bool consider_overlongs)527 S_is_utf8_cp_above_31_bits(const U8 * const s,
528                            const U8 * const e,
529                            const bool consider_overlongs)
530 {
531     /* Returns TRUE if the first code point represented by the Perl-extended-
532      * UTF-8-encoded string starting at 's', and looking no further than 'e -
533      * 1' doesn't fit into 31 bytes.  That is, that if it is >= 2**31.
534      *
535      * The function handles the case where the input bytes do not include all
536      * the ones necessary to represent a full character.  That is, they may be
537      * the intial bytes of the representation of a code point, but possibly
538      * the final ones necessary for the complete representation may be beyond
539      * 'e - 1'.
540      *
541      * The function also can handle the case where the input is an overlong
542      * sequence.  If 'consider_overlongs' is 0, the function assumes the
543      * input is not overlong, without checking, and will return based on that
544      * assumption.  If this parameter is 1, the function will go to the trouble
545      * of figuring out if it actually evaluates to above or below 31 bits.
546      *
547      * The sequence is otherwise assumed to be well-formed, without checking.
548      */
549 
550     const STRLEN len = e - s;
551     int is_overlong;
552 
553     PERL_ARGS_ASSERT_IS_UTF8_CP_ABOVE_31_BITS;
554 
555     assert(! UTF8_IS_INVARIANT(*s) && e > s);
556 
557 #ifdef EBCDIC
558 
559     PERL_UNUSED_ARG(consider_overlongs);
560 
561     /* On the EBCDIC code pages we handle, only the native start byte 0xFE can
562      * mean a 32-bit or larger code point (0xFF is an invariant).  0xFE can
563      * also be the start byte for a 31-bit code point; we need at least 2
564      * bytes, and maybe up through 8 bytes, to determine that.  (It can also be
565      * the start byte for an overlong sequence, but for 30-bit or smaller code
566      * points, so we don't have to worry about overlongs on EBCDIC.) */
567     if (*s != 0xFE) {
568         return 0;
569     }
570 
571     if (len == 1) {
572         return -1;
573     }
574 
575 #else
576 
577     /* On ASCII, FE and FF are the only start bytes that can evaluate to
578      * needing more than 31 bits. */
579     if (LIKELY(*s < 0xFE)) {
580         return 0;
581     }
582 
583     /* What we have left are FE and FF.  Both of these require more than 31
584      * bits unless they are for overlongs. */
585     if (! consider_overlongs) {
586         return 1;
587     }
588 
589     /* Here, we have FE or FF.  If the input isn't overlong, it evaluates to
590      * above 31 bits.  But we need more than one byte to discern this, so if
591      * passed just the start byte, it could be an overlong evaluating to
592      * smaller */
593     if (len == 1) {
594         return -1;
595     }
596 
597     /* Having excluded len==1, and knowing that FE and FF are both valid start
598      * bytes, we can call the function below to see if the sequence is
599      * overlong.  (We don't need the full generality of the called function,
600      * but for these huge code points, speed shouldn't be a consideration, and
601      * the compiler does have enough information, since it's static to this
602      * file, to optimize to just the needed parts.) */
603     is_overlong = is_utf8_overlong_given_start_byte_ok(s, len);
604 
605     /* If it isn't overlong, more than 31 bits are required. */
606     if (is_overlong == 0) {
607         return 1;
608     }
609 
610     /* If it is indeterminate if it is overlong, return that */
611     if (is_overlong < 0) {
612         return -1;
613     }
614 
615     /* Here is overlong.  Such a sequence starting with FE is below 31 bits, as
616      * the max it can be is 2**31 - 1 */
617     if (*s == 0xFE) {
618         return 0;
619     }
620 
621 #endif
622 
623     /* Here, ASCII and EBCDIC rejoin:
624     *  On ASCII:   We have an overlong sequence starting with FF
625     *  On EBCDIC:  We have a sequence starting with FE. */
626 
627     {   /* For C89, use a block so the declaration can be close to its use */
628 
629 #ifdef EBCDIC
630 
631         /* U+7FFFFFFF (2 ** 31 - 1)
632          *              [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] 10  11  12  13
633          *   IBM-1047: \xFE\x41\x41\x41\x41\x41\x41\x42\x73\x73\x73\x73\x73\x73
634          *    IBM-037: \xFE\x41\x41\x41\x41\x41\x41\x42\x72\x72\x72\x72\x72\x72
635          *   POSIX-BC: \xFE\x41\x41\x41\x41\x41\x41\x42\x75\x75\x75\x75\x75\x75
636          *         I8: \xFF\xA0\xA0\xA0\xA0\xA0\xA0\xA1\xBF\xBF\xBF\xBF\xBF\xBF
637          * U+80000000 (2 ** 31):
638          *   IBM-1047: \xFE\x41\x41\x41\x41\x41\x41\x43\x41\x41\x41\x41\x41\x41
639          *    IBM-037: \xFE\x41\x41\x41\x41\x41\x41\x43\x41\x41\x41\x41\x41\x41
640          *   POSIX-BC: \xFE\x41\x41\x41\x41\x41\x41\x43\x41\x41\x41\x41\x41\x41
641          *         I8: \xFF\xA0\xA0\xA0\xA0\xA0\xA0\xA2\xA0\xA0\xA0\xA0\xA0\xA0
642          *
643          * and since we know that *s = \xfe, any continuation sequcence
644          * following it that is gt the below is above 31 bits
645                                                 [0] [1] [2] [3] [4] [5] [6] */
646         const U8 conts_for_highest_30_bit[] = "\x41\x41\x41\x41\x41\x41\x42";
647 
648 #else
649 
650         /* FF overlong for U+7FFFFFFF (2 ** 31 - 1)
651          *      ASCII: \xFF\x80\x80\x80\x80\x80\x80\x81\xBF\xBF\xBF\xBF\xBF
652          * FF overlong for U+80000000 (2 ** 31):
653          *      ASCII: \xFF\x80\x80\x80\x80\x80\x80\x82\x80\x80\x80\x80\x80
654          * and since we know that *s = \xff, any continuation sequcence
655          * following it that is gt the below is above 30 bits
656                                                 [0] [1] [2] [3] [4] [5] [6] */
657         const U8 conts_for_highest_30_bit[] = "\x80\x80\x80\x80\x80\x80\x81";
658 
659 
660 #endif
661         const STRLEN conts_len = sizeof(conts_for_highest_30_bit) - 1;
662         const STRLEN cmp_len = MIN(conts_len, len - 1);
663 
664         /* Now compare the continuation bytes in s with the ones we have
665          * compiled in that are for the largest 30 bit code point.  If we have
666          * enough bytes available to determine the answer, or the bytes we do
667          * have differ from them, we can compare the two to get a definitive
668          * answer (Note that in UTF-EBCDIC, the two lowest possible
669          * continuation bytes are \x41 and \x42.) */
670         if (cmp_len >= conts_len || memNE(s + 1,
671                                           conts_for_highest_30_bit,
672                                           cmp_len))
673         {
674             return cBOOL(memGT(s + 1, conts_for_highest_30_bit, cmp_len));
675         }
676 
677         /* Here, all the bytes we have are the same as the highest 30-bit code
678          * point, but we are missing so many bytes that we can't make the
679          * determination */
680         return -1;
681     }
682 }
683 
684 #endif
685 
686 PERL_STATIC_INLINE int
S_is_utf8_overlong_given_start_byte_ok(const U8 * const s,const STRLEN len)687 S_is_utf8_overlong_given_start_byte_ok(const U8 * const s, const STRLEN len)
688 {
689     /* Returns an int indicating whether or not the UTF-8 sequence from 's' to
690      * 's' + 'len' - 1 is an overlong.  It returns 1 if it is an overlong; 0 if
691      * it isn't, and -1 if there isn't enough information to tell.  This last
692      * return value can happen if the sequence is incomplete, missing some
693      * trailing bytes that would form a complete character.  If there are
694      * enough bytes to make a definitive decision, this function does so.
695      * Usually 2 bytes sufficient.
696      *
697      * Overlongs can occur whenever the number of continuation bytes changes.
698      * That means whenever the number of leading 1 bits in a start byte
699      * increases from the next lower start byte.  That happens for start bytes
700      * C0, E0, F0, F8, FC, FE, and FF.  On modern perls, the following illegal
701      * start bytes have already been excluded, so don't need to be tested here;
702      * ASCII platforms: C0, C1
703      * EBCDIC platforms C0, C1, C2, C3, C4, E0
704      */
705 
706     const U8 s0 = NATIVE_UTF8_TO_I8(s[0]);
707     const U8 s1 = NATIVE_UTF8_TO_I8(s[1]);
708 
709     PERL_ARGS_ASSERT_IS_UTF8_OVERLONG_GIVEN_START_BYTE_OK;
710     assert(len > 1 && UTF8_IS_START(*s));
711 
712     /* Each platform has overlongs after the start bytes given above (expressed
713      * in I8 for EBCDIC).  What constitutes an overlong varies by platform, but
714      * the logic is the same, except the E0 overlong has already been excluded
715      * on EBCDIC platforms.   The  values below were found by manually
716      * inspecting the UTF-8 patterns.  See the tables in utf8.h and
717      * utfebcdic.h. */
718 
719 #       ifdef EBCDIC
720 #           define F0_ABOVE_OVERLONG 0xB0
721 #           define F8_ABOVE_OVERLONG 0xA8
722 #           define FC_ABOVE_OVERLONG 0xA4
723 #           define FE_ABOVE_OVERLONG 0xA2
724 #           define FF_OVERLONG_PREFIX "\xfe\x41\x41\x41\x41\x41\x41\x41"
725                                     /* I8(0xfe) is FF */
726 #       else
727 
728     if (s0 == 0xE0 && UNLIKELY(s1 < 0xA0)) {
729         return 1;
730     }
731 
732 #           define F0_ABOVE_OVERLONG 0x90
733 #           define F8_ABOVE_OVERLONG 0x88
734 #           define FC_ABOVE_OVERLONG 0x84
735 #           define FE_ABOVE_OVERLONG 0x82
736 #           define FF_OVERLONG_PREFIX "\xff\x80\x80\x80\x80\x80\x80"
737 #       endif
738 
739 
740     if (   (s0 == 0xF0 && UNLIKELY(s1 < F0_ABOVE_OVERLONG))
741         || (s0 == 0xF8 && UNLIKELY(s1 < F8_ABOVE_OVERLONG))
742         || (s0 == 0xFC && UNLIKELY(s1 < FC_ABOVE_OVERLONG))
743         || (s0 == 0xFE && UNLIKELY(s1 < FE_ABOVE_OVERLONG)))
744     {
745         return 1;
746     }
747 
748     /* Check for the FF overlong */
749     return isFF_OVERLONG(s, len);
750 }
751 
752 PERL_STATIC_INLINE int
S_isFF_OVERLONG(const U8 * const s,const STRLEN len)753 S_isFF_OVERLONG(const U8 * const s, const STRLEN len)
754 {
755     /* Returns an int indicating whether or not the UTF-8 sequence from 's' to
756      * 'e' - 1 is an overlong beginning with \xFF.  It returns 1 if it is; 0 if
757      * it isn't, and -1 if there isn't enough information to tell.  This last
758      * return value can happen if the sequence is incomplete, missing some
759      * trailing bytes that would form a complete character.  If there are
760      * enough bytes to make a definitive decision, this function does so. */
761 
762     PERL_ARGS_ASSERT_ISFF_OVERLONG;
763 
764     /* To be an FF overlong, all the available bytes must match */
765     if (LIKELY(memNE(s, FF_OVERLONG_PREFIX,
766                      MIN(len, sizeof(FF_OVERLONG_PREFIX) - 1))))
767     {
768         return 0;
769     }
770 
771     /* To be an FF overlong sequence, all the bytes in FF_OVERLONG_PREFIX must
772      * be there; what comes after them doesn't matter.  See tables in utf8.h,
773      * utfebcdic.h. */
774     if (len >= sizeof(FF_OVERLONG_PREFIX) - 1) {
775         return 1;
776     }
777 
778     /* The missing bytes could cause the result to go one way or the other, so
779      * the result is indeterminate */
780     return -1;
781 }
782 
783 #if defined(UV_IS_QUAD) /* These assume IV_MAX is 2**63-1 */
784 #  ifdef EBCDIC     /* Actually is I8 */
785 #   define HIGHEST_REPRESENTABLE_UTF8                                       \
786                 "\xFF\xA7\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF"
787 #  else
788 #   define HIGHEST_REPRESENTABLE_UTF8                                       \
789                 "\xFF\x80\x87\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF"
790 #  endif
791 #endif
792 
793 PERL_STATIC_INLINE int
S_does_utf8_overflow(const U8 * const s,const U8 * e,const bool consider_overlongs)794 S_does_utf8_overflow(const U8 * const s,
795                      const U8 * e,
796                      const bool consider_overlongs)
797 {
798     /* Returns an int indicating whether or not the UTF-8 sequence from 's' to
799      * 'e' - 1 would overflow an IV on this platform; that is if it represents
800      * a code point larger than the highest representable code point.  It
801      * returns 1 if it does overflow; 0 if it doesn't, and -1 if there isn't
802      * enough information to tell.  This last return value can happen if the
803      * sequence is incomplete, missing some trailing bytes that would form a
804      * complete character.  If there are enough bytes to make a definitive
805      * decision, this function does so.
806      *
807      * If 'consider_overlongs' is TRUE, the function checks for the possibility
808      * that the sequence is an overlong that doesn't overflow.  Otherwise, it
809      * assumes the sequence is not an overlong.  This can give different
810      * results only on ASCII 32-bit platforms.
811      *
812      * (For ASCII platforms, we could use memcmp() because we don't have to
813      * convert each byte to I8, but it's very rare input indeed that would
814      * approach overflow, so the loop below will likely only get executed once.)
815      *
816      * 'e' - 1 must not be beyond a full character. */
817 
818 
819     PERL_ARGS_ASSERT_DOES_UTF8_OVERFLOW;
820     assert(s <= e && s + UTF8SKIP(s) >= e);
821 
822 #if ! defined(UV_IS_QUAD)
823 
824     return is_utf8_cp_above_31_bits(s, e, consider_overlongs);
825 
826 #else
827 
828     PERL_UNUSED_ARG(consider_overlongs);
829 
830     {
831         const STRLEN len = e - s;
832         const U8 *x;
833         const U8 * y = (const U8 *) HIGHEST_REPRESENTABLE_UTF8;
834 
835         for (x = s; x < e; x++, y++) {
836 
837             if (UNLIKELY(NATIVE_UTF8_TO_I8(*x) == *y)) {
838                 continue;
839             }
840 
841             /* If this byte is larger than the corresponding highest UTF-8
842              * byte, the sequence overflow; otherwise the byte is less than,
843              * and so the sequence doesn't overflow */
844             return NATIVE_UTF8_TO_I8(*x) > *y;
845 
846         }
847 
848         /* Got to the end and all bytes are the same.  If the input is a whole
849          * character, it doesn't overflow.  And if it is a partial character,
850          * there's not enough information to tell */
851         if (len < sizeof(HIGHEST_REPRESENTABLE_UTF8) - 1) {
852             return -1;
853         }
854 
855         return 0;
856     }
857 
858 #endif
859 
860 }
861 
862 #if 0
863 
864 /* This is the portions of the above function that deal with UV_MAX instead of
865  * IV_MAX.  They are left here in case we want to combine them so that internal
866  * uses can have larger code points.  The only logic difference is that the
867  * 32-bit EBCDIC platform is treate like the 64-bit, and the 32-bit ASCII has
868  * different logic.
869  */
870 
871 /* Anything larger than this will overflow the word if it were converted into a UV */
872 #if defined(UV_IS_QUAD)
873 #  ifdef EBCDIC     /* Actually is I8 */
874 #   define HIGHEST_REPRESENTABLE_UTF8                                       \
875                 "\xFF\xAF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF"
876 #  else
877 #   define HIGHEST_REPRESENTABLE_UTF8                                       \
878                 "\xFF\x80\x8F\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF\xBF"
879 #  endif
880 #else   /* 32-bit */
881 #  ifdef EBCDIC
882 #   define HIGHEST_REPRESENTABLE_UTF8                                       \
883                 "\xFF\xA0\xA0\xA0\xA0\xA0\xA0\xA3\xBF\xBF\xBF\xBF\xBF\xBF"
884 #  else
885 #   define HIGHEST_REPRESENTABLE_UTF8  "\xFE\x83\xBF\xBF\xBF\xBF\xBF"
886 #  endif
887 #endif
888 
889 #if ! defined(UV_IS_QUAD) && ! defined(EBCDIC)
890 
891     /* On 32 bit ASCII machines, many overlongs that start with FF don't
892      * overflow */
893     if (consider_overlongs && isFF_OVERLONG(s, len) > 0) {
894 
895         /* To be such an overlong, the first bytes of 's' must match
896          * FF_OVERLONG_PREFIX, which is "\xff\x80\x80\x80\x80\x80\x80".  If we
897          * don't have any additional bytes available, the sequence, when
898          * completed might or might not fit in 32 bits.  But if we have that
899          * next byte, we can tell for sure.  If it is <= 0x83, then it does
900          * fit. */
901         if (len <= sizeof(FF_OVERLONG_PREFIX) - 1) {
902             return -1;
903         }
904 
905         return s[sizeof(FF_OVERLONG_PREFIX) - 1] > 0x83;
906     }
907 
908 /* Starting with the #else, the rest of the function is identical except
909  *      1.  we need to move the 'len' declaration to be global to the function
910  *      2.  the endif move to just after the UNUSED_ARG.
911  * An empty endif is given just below to satisfy the preprocessor
912  */
913 #endif
914 
915 #endif
916 
917 #undef F0_ABOVE_OVERLONG
918 #undef F8_ABOVE_OVERLONG
919 #undef FC_ABOVE_OVERLONG
920 #undef FE_ABOVE_OVERLONG
921 #undef FF_OVERLONG_PREFIX
922 
923 STRLEN
Perl__is_utf8_char_helper(const U8 * const s,const U8 * e,const U32 flags)924 Perl__is_utf8_char_helper(const U8 * const s, const U8 * e, const U32 flags)
925 {
926     STRLEN len;
927     const U8 *x;
928 
929     /* A helper function that should not be called directly.
930      *
931      * This function returns non-zero if the string beginning at 's' and
932      * looking no further than 'e - 1' is well-formed Perl-extended-UTF-8 for a
933      * code point; otherwise it returns 0.  The examination stops after the
934      * first code point in 's' is validated, not looking at the rest of the
935      * input.  If 'e' is such that there are not enough bytes to represent a
936      * complete code point, this function will return non-zero anyway, if the
937      * bytes it does have are well-formed UTF-8 as far as they go, and aren't
938      * excluded by 'flags'.
939      *
940      * A non-zero return gives the number of bytes required to represent the
941      * code point.  Be aware that if the input is for a partial character, the
942      * return will be larger than 'e - s'.
943      *
944      * This function assumes that the code point represented is UTF-8 variant.
945      * The caller should have excluded the possibility of it being invariant
946      * before calling this function.
947      *
948      * 'flags' can be 0, or any combination of the UTF8_DISALLOW_foo flags
949      * accepted by L</utf8n_to_uvchr>.  If non-zero, this function will return
950      * 0 if the code point represented is well-formed Perl-extended-UTF-8, but
951      * disallowed by the flags.  If the input is only for a partial character,
952      * the function will return non-zero if there is any sequence of
953      * well-formed UTF-8 that, when appended to the input sequence, could
954      * result in an allowed code point; otherwise it returns 0.  Non characters
955      * cannot be determined based on partial character input.  But many  of the
956      * other excluded types can be determined with just the first one or two
957      * bytes.
958      *
959      */
960 
961     PERL_ARGS_ASSERT__IS_UTF8_CHAR_HELPER;
962 
963     assert(0 == (flags & ~(UTF8_DISALLOW_ILLEGAL_INTERCHANGE
964                           |UTF8_DISALLOW_PERL_EXTENDED)));
965     assert(! UTF8_IS_INVARIANT(*s));
966 
967     /* A variant char must begin with a start byte */
968     if (UNLIKELY(! UTF8_IS_START(*s))) {
969         return 0;
970     }
971 
972     /* Examine a maximum of a single whole code point */
973     if (e - s > UTF8SKIP(s)) {
974         e = s + UTF8SKIP(s);
975     }
976 
977     len = e - s;
978 
979     if (flags && isUTF8_POSSIBLY_PROBLEMATIC(*s)) {
980         const U8 s0 = NATIVE_UTF8_TO_I8(s[0]);
981 
982         /* Here, we are disallowing some set of largish code points, and the
983          * first byte indicates the sequence is for a code point that could be
984          * in the excluded set.  We generally don't have to look beyond this or
985          * the second byte to see if the sequence is actually for one of the
986          * excluded classes.  The code below is derived from this table:
987          *
988          *              UTF-8            UTF-EBCDIC I8
989          *   U+D800: \xED\xA0\x80      \xF1\xB6\xA0\xA0      First surrogate
990          *   U+DFFF: \xED\xBF\xBF      \xF1\xB7\xBF\xBF      Final surrogate
991          * U+110000: \xF4\x90\x80\x80  \xF9\xA2\xA0\xA0\xA0  First above Unicode
992          *
993          * Keep in mind that legal continuation bytes range between \x80..\xBF
994          * for UTF-8, and \xA0..\xBF for I8.  Anything above those aren't
995          * continuation bytes.  Hence, we don't have to test the upper edge
996          * because if any of those is encountered, the sequence is malformed,
997          * and would fail elsewhere in this function.
998          *
999          * The code here likewise assumes that there aren't other
1000          * malformations; again the function should fail elsewhere because of
1001          * these.  For example, an overlong beginning with FC doesn't actually
1002          * have to be a super; it could actually represent a small code point,
1003          * even U+0000.  But, since overlongs (and other malformations) are
1004          * illegal, the function should return FALSE in either case.
1005          */
1006 
1007 #ifdef EBCDIC   /* On EBCDIC, these are actually I8 bytes */
1008 #  define FIRST_START_BYTE_THAT_IS_DEFINITELY_SUPER  0xFA
1009 #  define IS_UTF8_2_BYTE_SUPER(s0, s1)           ((s0) == 0xF9 && (s1) >= 0xA2)
1010 
1011 #  define IS_UTF8_2_BYTE_SURROGATE(s0, s1)       ((s0) == 0xF1              \
1012                                                        /* B6 and B7 */      \
1013                                               && ((s1) & 0xFE ) == 0xB6)
1014 #  define isUTF8_PERL_EXTENDED(s)   (*s == I8_TO_NATIVE_UTF8(0xFF))
1015 #else
1016 #  define FIRST_START_BYTE_THAT_IS_DEFINITELY_SUPER  0xF5
1017 #  define IS_UTF8_2_BYTE_SUPER(s0, s1)           ((s0) == 0xF4 && (s1) >= 0x90)
1018 #  define IS_UTF8_2_BYTE_SURROGATE(s0, s1)       ((s0) == 0xED && (s1) >= 0xA0)
1019 #  define isUTF8_PERL_EXTENDED(s)   (*s >= 0xFE)
1020 #endif
1021 
1022         if (  (flags & UTF8_DISALLOW_SUPER)
1023             && UNLIKELY(s0 >= FIRST_START_BYTE_THAT_IS_DEFINITELY_SUPER))
1024         {
1025             return 0;           /* Above Unicode */
1026         }
1027 
1028         if (   (flags & UTF8_DISALLOW_PERL_EXTENDED)
1029             &&  UNLIKELY(isUTF8_PERL_EXTENDED(s)))
1030         {
1031             return 0;
1032         }
1033 
1034         if (len > 1) {
1035             const U8 s1 = NATIVE_UTF8_TO_I8(s[1]);
1036 
1037             if (   (flags & UTF8_DISALLOW_SUPER)
1038                 &&  UNLIKELY(IS_UTF8_2_BYTE_SUPER(s0, s1)))
1039             {
1040                 return 0;       /* Above Unicode */
1041             }
1042 
1043             if (   (flags & UTF8_DISALLOW_SURROGATE)
1044                 &&  UNLIKELY(IS_UTF8_2_BYTE_SURROGATE(s0, s1)))
1045             {
1046                 return 0;       /* Surrogate */
1047             }
1048 
1049             if (  (flags & UTF8_DISALLOW_NONCHAR)
1050                 && UNLIKELY(UTF8_IS_NONCHAR(s, e)))
1051             {
1052                 return 0;       /* Noncharacter code point */
1053             }
1054         }
1055     }
1056 
1057     /* Make sure that all that follows are continuation bytes */
1058     for (x = s + 1; x < e; x++) {
1059         if (UNLIKELY(! UTF8_IS_CONTINUATION(*x))) {
1060             return 0;
1061         }
1062     }
1063 
1064     /* Here is syntactically valid.  Next, make sure this isn't the start of an
1065      * overlong. */
1066     if (len > 1 && is_utf8_overlong_given_start_byte_ok(s, len) > 0) {
1067         return 0;
1068     }
1069 
1070     /* And finally, that the code point represented fits in a word on this
1071      * platform */
1072     if (0 < does_utf8_overflow(s, e,
1073                                0 /* Don't consider overlongs */
1074                               ))
1075     {
1076         return 0;
1077     }
1078 
1079     return UTF8SKIP(s);
1080 }
1081 
1082 char *
Perl__byte_dump_string(pTHX_ const U8 * const start,const STRLEN len,const bool format)1083 Perl__byte_dump_string(pTHX_ const U8 * const start, const STRLEN len, const bool format)
1084 {
1085     /* Returns a mortalized C string that is a displayable copy of the 'len'
1086      * bytes starting at 'start'.  'format' gives how to display each byte.
1087      * Currently, there are only two formats, so it is currently a bool:
1088      *      0   \xab
1089      *      1    ab         (that is a space between two hex digit bytes)
1090      */
1091 
1092     const STRLEN output_len = 4 * len + 1;  /* 4 bytes per each input, plus a
1093                                                trailing NUL */
1094     const U8 * s = start;
1095     const U8 * const e = start + len;
1096     char * output;
1097     char * d;
1098 
1099     PERL_ARGS_ASSERT__BYTE_DUMP_STRING;
1100 
1101     Newx(output, output_len, char);
1102     SAVEFREEPV(output);
1103 
1104     d = output;
1105     for (s = start; s < e; s++) {
1106         const unsigned high_nibble = (*s & 0xF0) >> 4;
1107         const unsigned low_nibble =  (*s & 0x0F);
1108 
1109         if (format) {
1110             if (s > start) {
1111                 *d++ = ' ';
1112             }
1113         }
1114         else {
1115             *d++ = '\\';
1116             *d++ = 'x';
1117         }
1118 
1119         if (high_nibble < 10) {
1120             *d++ = high_nibble + '0';
1121         }
1122         else {
1123             *d++ = high_nibble - 10 + 'a';
1124         }
1125 
1126         if (low_nibble < 10) {
1127             *d++ = low_nibble + '0';
1128         }
1129         else {
1130             *d++ = low_nibble - 10 + 'a';
1131         }
1132     }
1133 
1134     *d = '\0';
1135     return output;
1136 }
1137 
1138 PERL_STATIC_INLINE char *
S_unexpected_non_continuation_text(pTHX_ const U8 * const s,STRLEN print_len,const STRLEN non_cont_byte_pos,const STRLEN expect_len)1139 S_unexpected_non_continuation_text(pTHX_ const U8 * const s,
1140 
1141                                          /* Max number of bytes to print */
1142                                          STRLEN print_len,
1143 
1144                                          /* Which one is the non-continuation */
1145                                          const STRLEN non_cont_byte_pos,
1146 
1147                                          /* How many bytes should there be? */
1148                                          const STRLEN expect_len)
1149 {
1150     /* Return the malformation warning text for an unexpected continuation
1151      * byte. */
1152 
1153     const char * const where = (non_cont_byte_pos == 1)
1154                                ? "immediately"
1155                                : Perl_form(aTHX_ "%d bytes",
1156                                                  (int) non_cont_byte_pos);
1157     const U8 * x = s + non_cont_byte_pos;
1158     const U8 * e = s + print_len;
1159 
1160     PERL_ARGS_ASSERT_UNEXPECTED_NON_CONTINUATION_TEXT;
1161 
1162     /* We don't need to pass this parameter, but since it has already been
1163      * calculated, it's likely faster to pass it; verify under DEBUGGING */
1164     assert(expect_len == UTF8SKIP(s));
1165 
1166     /* As a defensive coding measure, don't output anything past a NUL.  Such
1167      * bytes shouldn't be in the middle of a malformation, and could mark the
1168      * end of the allocated string, and what comes after is undefined */
1169     for (; x < e; x++) {
1170         if (*x == '\0') {
1171             x++;            /* Output this particular NUL */
1172             break;
1173         }
1174     }
1175 
1176     return Perl_form(aTHX_ "%s: %s (unexpected non-continuation byte 0x%02x,"
1177                            " %s after start byte 0x%02x; need %d bytes, got %d)",
1178                            malformed_text,
1179                            _byte_dump_string(s, x - s, 0),
1180                            *(s + non_cont_byte_pos),
1181                            where,
1182                            *s,
1183                            (int) expect_len,
1184                            (int) non_cont_byte_pos);
1185 }
1186 
1187 /*
1188 
1189 =for apidoc utf8n_to_uvchr
1190 
1191 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
1192 Most code should use L</utf8_to_uvchr_buf>() rather than call this directly.
1193 
1194 Bottom level UTF-8 decode routine.
1195 Returns the native code point value of the first character in the string C<s>,
1196 which is assumed to be in UTF-8 (or UTF-EBCDIC) encoding, and no longer than
1197 C<curlen> bytes; C<*retlen> (if C<retlen> isn't NULL) will be set to
1198 the length, in bytes, of that character.
1199 
1200 The value of C<flags> determines the behavior when C<s> does not point to a
1201 well-formed UTF-8 character.  If C<flags> is 0, encountering a malformation
1202 causes zero to be returned and C<*retlen> is set so that (S<C<s> + C<*retlen>>)
1203 is the next possible position in C<s> that could begin a non-malformed
1204 character.  Also, if UTF-8 warnings haven't been lexically disabled, a warning
1205 is raised.  Some UTF-8 input sequences may contain multiple malformations.
1206 This function tries to find every possible one in each call, so multiple
1207 warnings can be raised for the same sequence.
1208 
1209 Various ALLOW flags can be set in C<flags> to allow (and not warn on)
1210 individual types of malformations, such as the sequence being overlong (that
1211 is, when there is a shorter sequence that can express the same code point;
1212 overlong sequences are expressly forbidden in the UTF-8 standard due to
1213 potential security issues).  Another malformation example is the first byte of
1214 a character not being a legal first byte.  See F<utf8.h> for the list of such
1215 flags.  Even if allowed, this function generally returns the Unicode
1216 REPLACEMENT CHARACTER when it encounters a malformation.  There are flags in
1217 F<utf8.h> to override this behavior for the overlong malformations, but don't
1218 do that except for very specialized purposes.
1219 
1220 The C<UTF8_CHECK_ONLY> flag overrides the behavior when a non-allowed (by other
1221 flags) malformation is found.  If this flag is set, the routine assumes that
1222 the caller will raise a warning, and this function will silently just set
1223 C<retlen> to C<-1> (cast to C<STRLEN>) and return zero.
1224 
1225 Note that this API requires disambiguation between successful decoding a C<NUL>
1226 character, and an error return (unless the C<UTF8_CHECK_ONLY> flag is set), as
1227 in both cases, 0 is returned, and, depending on the malformation, C<retlen> may
1228 be set to 1.  To disambiguate, upon a zero return, see if the first byte of
1229 C<s> is 0 as well.  If so, the input was a C<NUL>; if not, the input had an
1230 error.  Or you can use C<L</utf8n_to_uvchr_error>>.
1231 
1232 Certain code points are considered problematic.  These are Unicode surrogates,
1233 Unicode non-characters, and code points above the Unicode maximum of 0x10FFFF.
1234 By default these are considered regular code points, but certain situations
1235 warrant special handling for them, which can be specified using the C<flags>
1236 parameter.  If C<flags> contains C<UTF8_DISALLOW_ILLEGAL_INTERCHANGE>, all
1237 three classes are treated as malformations and handled as such.  The flags
1238 C<UTF8_DISALLOW_SURROGATE>, C<UTF8_DISALLOW_NONCHAR>, and
1239 C<UTF8_DISALLOW_SUPER> (meaning above the legal Unicode maximum) can be set to
1240 disallow these categories individually.  C<UTF8_DISALLOW_ILLEGAL_INTERCHANGE>
1241 restricts the allowed inputs to the strict UTF-8 traditionally defined by
1242 Unicode.  Use C<UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE> to use the strictness
1243 definition given by
1244 L<Unicode Corrigendum #9|http://www.unicode.org/versions/corrigendum9.html>.
1245 The difference between traditional strictness and C9 strictness is that the
1246 latter does not forbid non-character code points.  (They are still discouraged,
1247 however.)  For more discussion see L<perlunicode/Noncharacter code points>.
1248 
1249 The flags C<UTF8_WARN_ILLEGAL_INTERCHANGE>,
1250 C<UTF8_WARN_ILLEGAL_C9_INTERCHANGE>, C<UTF8_WARN_SURROGATE>,
1251 C<UTF8_WARN_NONCHAR>, and C<UTF8_WARN_SUPER> will cause warning messages to be
1252 raised for their respective categories, but otherwise the code points are
1253 considered valid (not malformations).  To get a category to both be treated as
1254 a malformation and raise a warning, specify both the WARN and DISALLOW flags.
1255 (But note that warnings are not raised if lexically disabled nor if
1256 C<UTF8_CHECK_ONLY> is also specified.)
1257 
1258 Extremely high code points were never specified in any standard, and require an
1259 extension to UTF-8 to express, which Perl does.  It is likely that programs
1260 written in something other than Perl would not be able to read files that
1261 contain these; nor would Perl understand files written by something that uses a
1262 different extension.  For these reasons, there is a separate set of flags that
1263 can warn and/or disallow these extremely high code points, even if other
1264 above-Unicode ones are accepted.  They are the C<UTF8_WARN_PERL_EXTENDED> and
1265 C<UTF8_DISALLOW_PERL_EXTENDED> flags.  For more information see
1266 L</C<UTF8_GOT_PERL_EXTENDED>>.  Of course C<UTF8_DISALLOW_SUPER> will treat all
1267 above-Unicode code points, including these, as malformations.
1268 (Note that the Unicode standard considers anything above 0x10FFFF to be
1269 illegal, but there are standards predating it that allow up to 0x7FFF_FFFF
1270 (2**31 -1))
1271 
1272 A somewhat misleadingly named synonym for C<UTF8_WARN_PERL_EXTENDED> is
1273 retained for backward compatibility: C<UTF8_WARN_ABOVE_31_BIT>.  Similarly,
1274 C<UTF8_DISALLOW_ABOVE_31_BIT> is usable instead of the more accurately named
1275 C<UTF8_DISALLOW_PERL_EXTENDED>.  The names are misleading because these flags
1276 can apply to code points that actually do fit in 31 bits.  This happens on
1277 EBCDIC platforms, and sometimes when the L<overlong
1278 malformation|/C<UTF8_GOT_LONG>> is also present.  The new names accurately
1279 describe the situation in all cases.
1280 
1281 
1282 All other code points corresponding to Unicode characters, including private
1283 use and those yet to be assigned, are never considered malformed and never
1284 warn.
1285 
1286 =cut
1287 
1288 Also implemented as a macro in utf8.h
1289 */
1290 
1291 UV
Perl_utf8n_to_uvchr(const U8 * s,STRLEN curlen,STRLEN * retlen,const U32 flags)1292 Perl_utf8n_to_uvchr(const U8 *s,
1293                     STRLEN curlen,
1294                     STRLEN *retlen,
1295                     const U32 flags)
1296 {
1297     PERL_ARGS_ASSERT_UTF8N_TO_UVCHR;
1298 
1299     return utf8n_to_uvchr_error(s, curlen, retlen, flags, NULL);
1300 }
1301 
1302 /*
1303 
1304 =for apidoc utf8n_to_uvchr_error
1305 
1306 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
1307 Most code should use L</utf8_to_uvchr_buf>() rather than call this directly.
1308 
1309 This function is for code that needs to know what the precise malformation(s)
1310 are when an error is found.  If you also need to know the generated warning
1311 messages, use L</utf8n_to_uvchr_msgs>() instead.
1312 
1313 It is like C<L</utf8n_to_uvchr>> but it takes an extra parameter placed after
1314 all the others, C<errors>.  If this parameter is 0, this function behaves
1315 identically to C<L</utf8n_to_uvchr>>.  Otherwise, C<errors> should be a pointer
1316 to a C<U32> variable, which this function sets to indicate any errors found.
1317 Upon return, if C<*errors> is 0, there were no errors found.  Otherwise,
1318 C<*errors> is the bit-wise C<OR> of the bits described in the list below.  Some
1319 of these bits will be set if a malformation is found, even if the input
1320 C<flags> parameter indicates that the given malformation is allowed; those
1321 exceptions are noted:
1322 
1323 =over 4
1324 
1325 =item C<UTF8_GOT_PERL_EXTENDED>
1326 
1327 The input sequence is not standard UTF-8, but a Perl extension.  This bit is
1328 set only if the input C<flags> parameter contains either the
1329 C<UTF8_DISALLOW_PERL_EXTENDED> or the C<UTF8_WARN_PERL_EXTENDED> flags.
1330 
1331 Code points above 0x7FFF_FFFF (2**31 - 1) were never specified in any standard,
1332 and so some extension must be used to express them.  Perl uses a natural
1333 extension to UTF-8 to represent the ones up to 2**36-1, and invented a further
1334 extension to represent even higher ones, so that any code point that fits in a
1335 64-bit word can be represented.  Text using these extensions is not likely to
1336 be portable to non-Perl code.  We lump both of these extensions together and
1337 refer to them as Perl extended UTF-8.  There exist other extensions that people
1338 have invented, incompatible with Perl's.
1339 
1340 On EBCDIC platforms starting in Perl v5.24, the Perl extension for representing
1341 extremely high code points kicks in at 0x3FFF_FFFF (2**30 -1), which is lower
1342 than on ASCII.  Prior to that, code points 2**31 and higher were simply
1343 unrepresentable, and a different, incompatible method was used to represent
1344 code points between 2**30 and 2**31 - 1.
1345 
1346 On both platforms, ASCII and EBCDIC, C<UTF8_GOT_PERL_EXTENDED> is set if
1347 Perl extended UTF-8 is used.
1348 
1349 In earlier Perls, this bit was named C<UTF8_GOT_ABOVE_31_BIT>, which you still
1350 may use for backward compatibility.  That name is misleading, as this flag may
1351 be set when the code point actually does fit in 31 bits.  This happens on
1352 EBCDIC platforms, and sometimes when the L<overlong
1353 malformation|/C<UTF8_GOT_LONG>> is also present.  The new name accurately
1354 describes the situation in all cases.
1355 
1356 =item C<UTF8_GOT_CONTINUATION>
1357 
1358 The input sequence was malformed in that the first byte was a a UTF-8
1359 continuation byte.
1360 
1361 =item C<UTF8_GOT_EMPTY>
1362 
1363 The input C<curlen> parameter was 0.
1364 
1365 =item C<UTF8_GOT_LONG>
1366 
1367 The input sequence was malformed in that there is some other sequence that
1368 evaluates to the same code point, but that sequence is shorter than this one.
1369 
1370 Until Unicode 3.1, it was legal for programs to accept this malformation, but
1371 it was discovered that this created security issues.
1372 
1373 =item C<UTF8_GOT_NONCHAR>
1374 
1375 The code point represented by the input UTF-8 sequence is for a Unicode
1376 non-character code point.
1377 This bit is set only if the input C<flags> parameter contains either the
1378 C<UTF8_DISALLOW_NONCHAR> or the C<UTF8_WARN_NONCHAR> flags.
1379 
1380 =item C<UTF8_GOT_NON_CONTINUATION>
1381 
1382 The input sequence was malformed in that a non-continuation type byte was found
1383 in a position where only a continuation type one should be.  See also
1384 L</C<UTF8_GOT_SHORT>>.
1385 
1386 =item C<UTF8_GOT_OVERFLOW>
1387 
1388 The input sequence was malformed in that it is for a code point that is not
1389 representable in the number of bits available in an IV on the current platform.
1390 
1391 =item C<UTF8_GOT_SHORT>
1392 
1393 The input sequence was malformed in that C<curlen> is smaller than required for
1394 a complete sequence.  In other words, the input is for a partial character
1395 sequence.
1396 
1397 
1398 C<UTF8_GOT_SHORT> and C<UTF8_GOT_NON_CONTINUATION> both indicate a too short
1399 sequence.  The difference is that C<UTF8_GOT_NON_CONTINUATION> indicates always
1400 that there is an error, while C<UTF8_GOT_SHORT> means that an incomplete
1401 sequence was looked at.   If no other flags are present, it means that the
1402 sequence was valid as far as it went.  Depending on the application, this could
1403 mean one of three things:
1404 
1405 =over
1406 
1407 =item *
1408 
1409 The C<curlen> length parameter passed in was too small, and the function was
1410 prevented from examining all the necessary bytes.
1411 
1412 =item *
1413 
1414 The buffer being looked at is based on reading data, and the data received so
1415 far stopped in the middle of a character, so that the next read will
1416 read the remainder of this character.  (It is up to the caller to deal with the
1417 split bytes somehow.)
1418 
1419 =item *
1420 
1421 This is a real error, and the partial sequence is all we're going to get.
1422 
1423 =back
1424 
1425 =item C<UTF8_GOT_SUPER>
1426 
1427 The input sequence was malformed in that it is for a non-Unicode code point;
1428 that is, one above the legal Unicode maximum.
1429 This bit is set only if the input C<flags> parameter contains either the
1430 C<UTF8_DISALLOW_SUPER> or the C<UTF8_WARN_SUPER> flags.
1431 
1432 =item C<UTF8_GOT_SURROGATE>
1433 
1434 The input sequence was malformed in that it is for a -Unicode UTF-16 surrogate
1435 code point.
1436 This bit is set only if the input C<flags> parameter contains either the
1437 C<UTF8_DISALLOW_SURROGATE> or the C<UTF8_WARN_SURROGATE> flags.
1438 
1439 =back
1440 
1441 To do your own error handling, call this function with the C<UTF8_CHECK_ONLY>
1442 flag to suppress any warnings, and then examine the C<*errors> return.
1443 
1444 =cut
1445 
1446 Also implemented as a macro in utf8.h
1447 */
1448 
1449 UV
Perl_utf8n_to_uvchr_error(const U8 * s,STRLEN curlen,STRLEN * retlen,const U32 flags,U32 * errors)1450 Perl_utf8n_to_uvchr_error(const U8 *s,
1451                           STRLEN curlen,
1452                           STRLEN *retlen,
1453                           const U32 flags,
1454                           U32 * errors)
1455 {
1456     PERL_ARGS_ASSERT_UTF8N_TO_UVCHR_ERROR;
1457 
1458     return utf8n_to_uvchr_msgs(s, curlen, retlen, flags, errors, NULL);
1459 }
1460 
1461 /*
1462 
1463 =for apidoc utf8n_to_uvchr_msgs
1464 
1465 THIS FUNCTION SHOULD BE USED IN ONLY VERY SPECIALIZED CIRCUMSTANCES.
1466 Most code should use L</utf8_to_uvchr_buf>() rather than call this directly.
1467 
1468 This function is for code that needs to know what the precise malformation(s)
1469 are when an error is found, and wants the corresponding warning and/or error
1470 messages to be returned to the caller rather than be displayed.  All messages
1471 that would have been displayed if all lexcial warnings are enabled will be
1472 returned.
1473 
1474 It is just like C<L</utf8n_to_uvchr_error>> but it takes an extra parameter
1475 placed after all the others, C<msgs>.  If this parameter is 0, this function
1476 behaves identically to C<L</utf8n_to_uvchr_error>>.  Otherwise, C<msgs> should
1477 be a pointer to an C<AV *> variable, in which this function creates a new AV to
1478 contain any appropriate messages.  The elements of the array are ordered so
1479 that the first message that would have been displayed is in the 0th element,
1480 and so on.  Each element is a hash with three key-value pairs, as follows:
1481 
1482 =over 4
1483 
1484 =item C<text>
1485 
1486 The text of the message as a C<SVpv>.
1487 
1488 =item C<warn_categories>
1489 
1490 The warning category (or categories) packed into a C<SVuv>.
1491 
1492 =item C<flag>
1493 
1494 A single flag bit associated with this message, in a C<SVuv>.
1495 The bit corresponds to some bit in the C<*errors> return value,
1496 such as C<UTF8_GOT_LONG>.
1497 
1498 =back
1499 
1500 It's important to note that specifying this parameter as non-null will cause
1501 any warnings this function would otherwise generate to be suppressed, and
1502 instead be placed in C<*msgs>.  The caller can check the lexical warnings state
1503 (or not) when choosing what to do with the returned messages.
1504 
1505 If the flag C<UTF8_CHECK_ONLY> is passed, no warnings are generated, and hence
1506 no AV is created.
1507 
1508 The caller, of course, is responsible for freeing any returned AV.
1509 
1510 =cut
1511 */
1512 
1513 UV
Perl__utf8n_to_uvchr_msgs_helper(const U8 * s,STRLEN curlen,STRLEN * retlen,const U32 flags,U32 * errors,AV ** msgs)1514 Perl__utf8n_to_uvchr_msgs_helper(const U8 *s,
1515                                STRLEN curlen,
1516                                STRLEN *retlen,
1517                                const U32 flags,
1518                                U32 * errors,
1519                                AV ** msgs)
1520 {
1521     const U8 * const s0 = s;
1522     const U8 * send = s0 + curlen;
1523     U32 possible_problems;  /* A bit is set here for each potential problem
1524                                found as we go along */
1525     UV uv;
1526     STRLEN expectlen;     /* How long should this sequence be? */
1527     STRLEN avail_len;     /* When input is too short, gives what that is */
1528     U32 discard_errors;   /* Used to save branches when 'errors' is NULL; this
1529                              gets set and discarded */
1530 
1531     /* The below are used only if there is both an overlong malformation and a
1532      * too short one.  Otherwise the first two are set to 's0' and 'send', and
1533      * the third not used at all */
1534     U8 * adjusted_s0;
1535     U8 temp_char_buf[UTF8_MAXBYTES + 1]; /* Used to avoid a Newx in this
1536                                             routine; see [perl #130921] */
1537     UV uv_so_far;
1538     dTHX;
1539 
1540     PERL_ARGS_ASSERT__UTF8N_TO_UVCHR_MSGS_HELPER;
1541 
1542     /* Here, is one of: a) malformed; b) a problematic code point (surrogate,
1543      * non-unicode, or nonchar); or c) on ASCII platforms, one of the Hangul
1544      * syllables that the dfa doesn't properly handle.  Quickly dispose of the
1545      * final case. */
1546 
1547 #ifndef EBCDIC
1548 
1549     /* Each of the affected Hanguls starts with \xED */
1550 
1551     if (is_HANGUL_ED_utf8_safe(s0, send)) {
1552         if (retlen) {
1553             *retlen = 3;
1554         }
1555         if (errors) {
1556             *errors = 0;
1557         }
1558         if (msgs) {
1559             *msgs = NULL;
1560         }
1561 
1562         return ((0xED & UTF_START_MASK(3)) << (2 * UTF_ACCUMULATION_SHIFT))
1563              | ((s0[1] & UTF_CONTINUATION_MASK) << UTF_ACCUMULATION_SHIFT)
1564              |  (s0[2] & UTF_CONTINUATION_MASK);
1565     }
1566 
1567 #endif
1568 
1569     /* In conjunction with the exhaustive tests that can be enabled in
1570      * APItest/t/utf8_warn_base.pl, this can make sure the dfa does precisely
1571      * what it is intended to do, and that no flaws in it are masked by
1572      * dropping down and executing the code below
1573     assert(! isUTF8_CHAR(s0, send)
1574           || UTF8_IS_SURROGATE(s0, send)
1575           || UTF8_IS_SUPER(s0, send)
1576           || UTF8_IS_NONCHAR(s0,send));
1577     */
1578 
1579     s = s0;
1580     uv = *s0;
1581     possible_problems = 0;
1582     expectlen = 0;
1583     avail_len = 0;
1584     discard_errors = 0;
1585     adjusted_s0 = (U8 *) s0;
1586     uv_so_far = 0;
1587 
1588     if (errors) {
1589         *errors = 0;
1590     }
1591     else {
1592         errors = &discard_errors;
1593     }
1594 
1595     /* The order of malformation tests here is important.  We should consume as
1596      * few bytes as possible in order to not skip any valid character.  This is
1597      * required by the Unicode Standard (section 3.9 of Unicode 6.0); see also
1598      * http://unicode.org/reports/tr36 for more discussion as to why.  For
1599      * example, once we've done a UTF8SKIP, we can tell the expected number of
1600      * bytes, and could fail right off the bat if the input parameters indicate
1601      * that there are too few available.  But it could be that just that first
1602      * byte is garbled, and the intended character occupies fewer bytes.  If we
1603      * blindly assumed that the first byte is correct, and skipped based on
1604      * that number, we could skip over a valid input character.  So instead, we
1605      * always examine the sequence byte-by-byte.
1606      *
1607      * We also should not consume too few bytes, otherwise someone could inject
1608      * things.  For example, an input could be deliberately designed to
1609      * overflow, and if this code bailed out immediately upon discovering that,
1610      * returning to the caller C<*retlen> pointing to the very next byte (one
1611      * which is actually part of of the overflowing sequence), that could look
1612      * legitimate to the caller, which could discard the initial partial
1613      * sequence and process the rest, inappropriately.
1614      *
1615      * Some possible input sequences are malformed in more than one way.  This
1616      * function goes to lengths to try to find all of them.  This is necessary
1617      * for correctness, as the inputs may allow one malformation but not
1618      * another, and if we abandon searching for others after finding the
1619      * allowed one, we could allow in something that shouldn't have been.
1620      */
1621 
1622     if (UNLIKELY(curlen == 0)) {
1623         possible_problems |= UTF8_GOT_EMPTY;
1624         curlen = 0;
1625         uv = UNICODE_REPLACEMENT;
1626 	goto ready_to_handle_errors;
1627     }
1628 
1629     expectlen = UTF8SKIP(s);
1630 
1631     /* A well-formed UTF-8 character, as the vast majority of calls to this
1632      * function will be for, has this expected length.  For efficiency, set
1633      * things up here to return it.  It will be overriden only in those rare
1634      * cases where a malformation is found */
1635     if (retlen) {
1636 	*retlen = expectlen;
1637     }
1638 
1639     /* A continuation character can't start a valid sequence */
1640     if (UNLIKELY(UTF8_IS_CONTINUATION(uv))) {
1641 	possible_problems |= UTF8_GOT_CONTINUATION;
1642         curlen = 1;
1643         uv = UNICODE_REPLACEMENT;
1644 	goto ready_to_handle_errors;
1645     }
1646 
1647     /* Here is not a continuation byte, nor an invariant.  The only thing left
1648      * is a start byte (possibly for an overlong).  (We can't use UTF8_IS_START
1649      * because it excludes start bytes like \xC0 that always lead to
1650      * overlongs.) */
1651 
1652     /* Convert to I8 on EBCDIC (no-op on ASCII), then remove the leading bits
1653      * that indicate the number of bytes in the character's whole UTF-8
1654      * sequence, leaving just the bits that are part of the value.  */
1655     uv = NATIVE_UTF8_TO_I8(uv) & UTF_START_MASK(expectlen);
1656 
1657     /* Setup the loop end point, making sure to not look past the end of the
1658      * input string, and flag it as too short if the size isn't big enough. */
1659     if (UNLIKELY(curlen < expectlen)) {
1660         possible_problems |= UTF8_GOT_SHORT;
1661         avail_len = curlen;
1662     }
1663     else {
1664         send = (U8*) s0 + expectlen;
1665     }
1666 
1667     /* Now, loop through the remaining bytes in the character's sequence,
1668      * accumulating each into the working value as we go. */
1669     for (s = s0 + 1; s < send; s++) {
1670 	if (LIKELY(UTF8_IS_CONTINUATION(*s))) {
1671 	    uv = UTF8_ACCUMULATE(uv, *s);
1672             continue;
1673         }
1674 
1675         /* Here, found a non-continuation before processing all expected bytes.
1676          * This byte indicates the beginning of a new character, so quit, even
1677          * if allowing this malformation. */
1678         possible_problems |= UTF8_GOT_NON_CONTINUATION;
1679         break;
1680     } /* End of loop through the character's bytes */
1681 
1682     /* Save how many bytes were actually in the character */
1683     curlen = s - s0;
1684 
1685     /* Note that there are two types of too-short malformation.  One is when
1686      * there is actual wrong data before the normal termination of the
1687      * sequence.  The other is that the sequence wasn't complete before the end
1688      * of the data we are allowed to look at, based on the input 'curlen'.
1689      * This means that we were passed data for a partial character, but it is
1690      * valid as far as we saw.  The other is definitely invalid.  This
1691      * distinction could be important to a caller, so the two types are kept
1692      * separate.
1693      *
1694      * A convenience macro that matches either of the too-short conditions.  */
1695 #   define UTF8_GOT_TOO_SHORT (UTF8_GOT_SHORT|UTF8_GOT_NON_CONTINUATION)
1696 
1697     if (UNLIKELY(possible_problems & UTF8_GOT_TOO_SHORT)) {
1698         uv_so_far = uv;
1699         uv = UNICODE_REPLACEMENT;
1700     }
1701 
1702     /* Check for overflow.  The algorithm requires us to not look past the end
1703      * of the current character, even if partial, so the upper limit is 's' */
1704     if (UNLIKELY(0 < does_utf8_overflow(s0, s,
1705                                          1 /* Do consider overlongs */
1706                                         )))
1707     {
1708         possible_problems |= UTF8_GOT_OVERFLOW;
1709         uv = UNICODE_REPLACEMENT;
1710     }
1711 
1712     /* Check for overlong.  If no problems so far, 'uv' is the correct code
1713      * point value.  Simply see if it is expressible in fewer bytes.  Otherwise
1714      * we must look at the UTF-8 byte sequence itself to see if it is for an
1715      * overlong */
1716     if (     (   LIKELY(! possible_problems)
1717               && UNLIKELY(expectlen > (STRLEN) OFFUNISKIP(uv)))
1718         || (       UNLIKELY(possible_problems)
1719             && (   UNLIKELY(! UTF8_IS_START(*s0))
1720                 || (   curlen > 1
1721                     && UNLIKELY(0 < is_utf8_overlong_given_start_byte_ok(s0,
1722                                                                 s - s0))))))
1723     {
1724         possible_problems |= UTF8_GOT_LONG;
1725 
1726         if (   UNLIKELY(   possible_problems & UTF8_GOT_TOO_SHORT)
1727 
1728                           /* The calculation in the 'true' branch of this 'if'
1729                            * below won't work if overflows, and isn't needed
1730                            * anyway.  Further below we handle all overflow
1731                            * cases */
1732             &&   LIKELY(! (possible_problems & UTF8_GOT_OVERFLOW)))
1733         {
1734             UV min_uv = uv_so_far;
1735             STRLEN i;
1736 
1737             /* Here, the input is both overlong and is missing some trailing
1738              * bytes.  There is no single code point it could be for, but there
1739              * may be enough information present to determine if what we have
1740              * so far is for an unallowed code point, such as for a surrogate.
1741              * The code further below has the intelligence to determine this,
1742              * but just for non-overlong UTF-8 sequences.  What we do here is
1743              * calculate the smallest code point the input could represent if
1744              * there were no too short malformation.  Then we compute and save
1745              * the UTF-8 for that, which is what the code below looks at
1746              * instead of the raw input.  It turns out that the smallest such
1747              * code point is all we need. */
1748             for (i = curlen; i < expectlen; i++) {
1749                 min_uv = UTF8_ACCUMULATE(min_uv,
1750                                      I8_TO_NATIVE_UTF8(UTF_CONTINUATION_MARK));
1751             }
1752 
1753             adjusted_s0 = temp_char_buf;
1754             (void) uvoffuni_to_utf8_flags(adjusted_s0, min_uv, 0);
1755         }
1756     }
1757 
1758     /* Here, we have found all the possible problems, except for when the input
1759      * is for a problematic code point not allowed by the input parameters. */
1760 
1761                                 /* uv is valid for overlongs */
1762     if (   (   (      LIKELY(! (possible_problems & ~UTF8_GOT_LONG))
1763 
1764                       /* isn't problematic if < this */
1765                    && uv >= UNICODE_SURROGATE_FIRST)
1766             || (   UNLIKELY(possible_problems)
1767 
1768                           /* if overflow, we know without looking further
1769                            * precisely which of the problematic types it is,
1770                            * and we deal with those in the overflow handling
1771                            * code */
1772                 && LIKELY(! (possible_problems & UTF8_GOT_OVERFLOW))
1773                 && (   isUTF8_POSSIBLY_PROBLEMATIC(*adjusted_s0)
1774                     || UNLIKELY(isUTF8_PERL_EXTENDED(s0)))))
1775 	&& ((flags & ( UTF8_DISALLOW_NONCHAR
1776                       |UTF8_DISALLOW_SURROGATE
1777                       |UTF8_DISALLOW_SUPER
1778                       |UTF8_DISALLOW_PERL_EXTENDED
1779 	              |UTF8_WARN_NONCHAR
1780                       |UTF8_WARN_SURROGATE
1781                       |UTF8_WARN_SUPER
1782                       |UTF8_WARN_PERL_EXTENDED))))
1783     {
1784         /* If there were no malformations, or the only malformation is an
1785          * overlong, 'uv' is valid */
1786         if (LIKELY(! (possible_problems & ~UTF8_GOT_LONG))) {
1787             if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
1788                 possible_problems |= UTF8_GOT_SURROGATE;
1789             }
1790             else if (UNLIKELY(uv > PERL_UNICODE_MAX)) {
1791                 possible_problems |= UTF8_GOT_SUPER;
1792             }
1793             else if (UNLIKELY(UNICODE_IS_NONCHAR(uv))) {
1794                 possible_problems |= UTF8_GOT_NONCHAR;
1795             }
1796         }
1797         else {  /* Otherwise, need to look at the source UTF-8, possibly
1798                    adjusted to be non-overlong */
1799 
1800             if (UNLIKELY(NATIVE_UTF8_TO_I8(*adjusted_s0)
1801                                 >= FIRST_START_BYTE_THAT_IS_DEFINITELY_SUPER))
1802             {
1803                 possible_problems |= UTF8_GOT_SUPER;
1804             }
1805             else if (curlen > 1) {
1806                 if (UNLIKELY(IS_UTF8_2_BYTE_SUPER(
1807                                       NATIVE_UTF8_TO_I8(*adjusted_s0),
1808                                       NATIVE_UTF8_TO_I8(*(adjusted_s0 + 1)))))
1809                 {
1810                     possible_problems |= UTF8_GOT_SUPER;
1811                 }
1812                 else if (UNLIKELY(IS_UTF8_2_BYTE_SURROGATE(
1813                                       NATIVE_UTF8_TO_I8(*adjusted_s0),
1814                                       NATIVE_UTF8_TO_I8(*(adjusted_s0 + 1)))))
1815                 {
1816                     possible_problems |= UTF8_GOT_SURROGATE;
1817                 }
1818             }
1819 
1820             /* We need a complete well-formed UTF-8 character to discern
1821              * non-characters, so can't look for them here */
1822         }
1823     }
1824 
1825   ready_to_handle_errors:
1826 
1827     /* At this point:
1828      * curlen               contains the number of bytes in the sequence that
1829      *                      this call should advance the input by.
1830      * avail_len            gives the available number of bytes passed in, but
1831      *                      only if this is less than the expected number of
1832      *                      bytes, based on the code point's start byte.
1833      * possible_problems'   is 0 if there weren't any problems; otherwise a bit
1834      *                      is set in it for each potential problem found.
1835      * uv                   contains the code point the input sequence
1836      *                      represents; or if there is a problem that prevents
1837      *                      a well-defined value from being computed, it is
1838      *                      some subsitute value, typically the REPLACEMENT
1839      *                      CHARACTER.
1840      * s0                   points to the first byte of the character
1841      * s                    points to just after were we left off processing
1842      *                      the character
1843      * send                 points to just after where that character should
1844      *                      end, based on how many bytes the start byte tells
1845      *                      us should be in it, but no further than s0 +
1846      *                      avail_len
1847      */
1848 
1849     if (UNLIKELY(possible_problems)) {
1850         bool disallowed = FALSE;
1851         const U32 orig_problems = possible_problems;
1852 
1853         if (msgs) {
1854             *msgs = NULL;
1855         }
1856 
1857         while (possible_problems) { /* Handle each possible problem */
1858             UV pack_warn = 0;
1859             char * message = NULL;
1860             U32 this_flag_bit = 0;
1861 
1862             /* Each 'if' clause handles one problem.  They are ordered so that
1863              * the first ones' messages will be displayed before the later
1864              * ones; this is kinda in decreasing severity order.  But the
1865              * overlong must come last, as it changes 'uv' looked at by the
1866              * others */
1867             if (possible_problems & UTF8_GOT_OVERFLOW) {
1868 
1869                 /* Overflow means also got a super and are using Perl's
1870                  * extended UTF-8, but we handle all three cases here */
1871                 possible_problems
1872                   &= ~(UTF8_GOT_OVERFLOW|UTF8_GOT_SUPER|UTF8_GOT_PERL_EXTENDED);
1873                 *errors |= UTF8_GOT_OVERFLOW;
1874 
1875                 /* But the API says we flag all errors found */
1876                 if (flags & (UTF8_WARN_SUPER|UTF8_DISALLOW_SUPER)) {
1877                     *errors |= UTF8_GOT_SUPER;
1878                 }
1879                 if (flags
1880                         & (UTF8_WARN_PERL_EXTENDED|UTF8_DISALLOW_PERL_EXTENDED))
1881                 {
1882                     *errors |= UTF8_GOT_PERL_EXTENDED;
1883                 }
1884 
1885                 /* Disallow if any of the three categories say to */
1886                 if ( ! (flags &   UTF8_ALLOW_OVERFLOW)
1887                     || (flags & ( UTF8_DISALLOW_SUPER
1888                                  |UTF8_DISALLOW_PERL_EXTENDED)))
1889                 {
1890                     disallowed = TRUE;
1891                 }
1892 
1893                 /* Likewise, warn if any say to */
1894                 if (  ! (flags & UTF8_ALLOW_OVERFLOW)
1895                     ||  (flags & (UTF8_WARN_SUPER|UTF8_WARN_PERL_EXTENDED)))
1896                 {
1897 
1898                     /* The warnings code explicitly says it doesn't handle the
1899                      * case of packWARN2 and two categories which have
1900                      * parent-child relationship.  Even if it works now to
1901                      * raise the warning if either is enabled, it wouldn't
1902                      * necessarily do so in the future.  We output (only) the
1903                      * most dire warning */
1904                     if (! (flags & UTF8_CHECK_ONLY)) {
1905                         if (msgs || ckWARN_d(WARN_UTF8)) {
1906                             pack_warn = packWARN(WARN_UTF8);
1907                         }
1908                         else if (msgs || ckWARN_d(WARN_NON_UNICODE)) {
1909                             pack_warn = packWARN(WARN_NON_UNICODE);
1910                         }
1911                         if (pack_warn) {
1912                             message = Perl_form(aTHX_ "%s: %s (overflows)",
1913                                             malformed_text,
1914                                             _byte_dump_string(s0, curlen, 0));
1915                             this_flag_bit = UTF8_GOT_OVERFLOW;
1916                         }
1917                     }
1918                 }
1919             }
1920             else if (possible_problems & UTF8_GOT_EMPTY) {
1921                 possible_problems &= ~UTF8_GOT_EMPTY;
1922                 *errors |= UTF8_GOT_EMPTY;
1923 
1924                 if (! (flags & UTF8_ALLOW_EMPTY)) {
1925 
1926                     /* This so-called malformation is now treated as a bug in
1927                      * the caller.  If you have nothing to decode, skip calling
1928                      * this function */
1929                     assert(0);
1930 
1931                     disallowed = TRUE;
1932                     if (  (msgs
1933                         || ckWARN_d(WARN_UTF8)) && ! (flags & UTF8_CHECK_ONLY))
1934                     {
1935                         pack_warn = packWARN(WARN_UTF8);
1936                         message = Perl_form(aTHX_ "%s (empty string)",
1937                                                    malformed_text);
1938                         this_flag_bit = UTF8_GOT_EMPTY;
1939                     }
1940                 }
1941             }
1942             else if (possible_problems & UTF8_GOT_CONTINUATION) {
1943                 possible_problems &= ~UTF8_GOT_CONTINUATION;
1944                 *errors |= UTF8_GOT_CONTINUATION;
1945 
1946                 if (! (flags & UTF8_ALLOW_CONTINUATION)) {
1947                     disallowed = TRUE;
1948                     if ((   msgs
1949                          || ckWARN_d(WARN_UTF8)) && ! (flags & UTF8_CHECK_ONLY))
1950                     {
1951                         pack_warn = packWARN(WARN_UTF8);
1952                         message = Perl_form(aTHX_
1953                                 "%s: %s (unexpected continuation byte 0x%02x,"
1954                                 " with no preceding start byte)",
1955                                 malformed_text,
1956                                 _byte_dump_string(s0, 1, 0), *s0);
1957                         this_flag_bit = UTF8_GOT_CONTINUATION;
1958                     }
1959                 }
1960             }
1961             else if (possible_problems & UTF8_GOT_SHORT) {
1962                 possible_problems &= ~UTF8_GOT_SHORT;
1963                 *errors |= UTF8_GOT_SHORT;
1964 
1965                 if (! (flags & UTF8_ALLOW_SHORT)) {
1966                     disallowed = TRUE;
1967                     if ((   msgs
1968                          || ckWARN_d(WARN_UTF8)) && ! (flags & UTF8_CHECK_ONLY))
1969                     {
1970                         pack_warn = packWARN(WARN_UTF8);
1971                         message = Perl_form(aTHX_
1972                              "%s: %s (too short; %d byte%s available, need %d)",
1973                              malformed_text,
1974                              _byte_dump_string(s0, send - s0, 0),
1975                              (int)avail_len,
1976                              avail_len == 1 ? "" : "s",
1977                              (int)expectlen);
1978                         this_flag_bit = UTF8_GOT_SHORT;
1979                     }
1980                 }
1981 
1982             }
1983             else if (possible_problems & UTF8_GOT_NON_CONTINUATION) {
1984                 possible_problems &= ~UTF8_GOT_NON_CONTINUATION;
1985                 *errors |= UTF8_GOT_NON_CONTINUATION;
1986 
1987                 if (! (flags & UTF8_ALLOW_NON_CONTINUATION)) {
1988                     disallowed = TRUE;
1989                     if ((   msgs
1990                          || ckWARN_d(WARN_UTF8)) && ! (flags & UTF8_CHECK_ONLY))
1991                     {
1992 
1993                         /* If we don't know for sure that the input length is
1994                          * valid, avoid as much as possible reading past the
1995                          * end of the buffer */
1996                         int printlen = (flags & _UTF8_NO_CONFIDENCE_IN_CURLEN)
1997                                        ? s - s0
1998                                        : send - s0;
1999                         pack_warn = packWARN(WARN_UTF8);
2000                         message = Perl_form(aTHX_ "%s",
2001                             unexpected_non_continuation_text(s0,
2002                                                             printlen,
2003                                                             s - s0,
2004                                                             (int) expectlen));
2005                         this_flag_bit = UTF8_GOT_NON_CONTINUATION;
2006                     }
2007                 }
2008             }
2009             else if (possible_problems & UTF8_GOT_SURROGATE) {
2010                 possible_problems &= ~UTF8_GOT_SURROGATE;
2011 
2012                 if (flags & UTF8_WARN_SURROGATE) {
2013                     *errors |= UTF8_GOT_SURROGATE;
2014 
2015                     if (   ! (flags & UTF8_CHECK_ONLY)
2016                         && (msgs || ckWARN_d(WARN_SURROGATE)))
2017                     {
2018                         pack_warn = packWARN(WARN_SURROGATE);
2019 
2020                         /* These are the only errors that can occur with a
2021                         * surrogate when the 'uv' isn't valid */
2022                         if (orig_problems & UTF8_GOT_TOO_SHORT) {
2023                             message = Perl_form(aTHX_
2024                                     "UTF-16 surrogate (any UTF-8 sequence that"
2025                                     " starts with \"%s\" is for a surrogate)",
2026                                     _byte_dump_string(s0, curlen, 0));
2027                         }
2028                         else {
2029                             message = Perl_form(aTHX_ surrogate_cp_format, uv);
2030                         }
2031                         this_flag_bit = UTF8_GOT_SURROGATE;
2032                     }
2033                 }
2034 
2035                 if (flags & UTF8_DISALLOW_SURROGATE) {
2036                     disallowed = TRUE;
2037                     *errors |= UTF8_GOT_SURROGATE;
2038                 }
2039             }
2040             else if (possible_problems & UTF8_GOT_SUPER) {
2041                 possible_problems &= ~UTF8_GOT_SUPER;
2042 
2043                 if (flags & UTF8_WARN_SUPER) {
2044                     *errors |= UTF8_GOT_SUPER;
2045 
2046                     if (   ! (flags & UTF8_CHECK_ONLY)
2047                         && (msgs || ckWARN_d(WARN_NON_UNICODE)))
2048                     {
2049                         pack_warn = packWARN(WARN_NON_UNICODE);
2050 
2051                         if (orig_problems & UTF8_GOT_TOO_SHORT) {
2052                             message = Perl_form(aTHX_
2053                                     "Any UTF-8 sequence that starts with"
2054                                     " \"%s\" is for a non-Unicode code point,"
2055                                     " may not be portable",
2056                                     _byte_dump_string(s0, curlen, 0));
2057                         }
2058                         else {
2059                             message = Perl_form(aTHX_ super_cp_format, uv);
2060                         }
2061                         this_flag_bit = UTF8_GOT_SUPER;
2062                     }
2063                 }
2064 
2065                 /* Test for Perl's extended UTF-8 after the regular SUPER ones,
2066                  * and before possibly bailing out, so that the more dire
2067                  * warning will override the regular one. */
2068                 if (UNLIKELY(isUTF8_PERL_EXTENDED(s0))) {
2069                     if (  ! (flags & UTF8_CHECK_ONLY)
2070                         &&  (flags & (UTF8_WARN_PERL_EXTENDED|UTF8_WARN_SUPER))
2071                         &&  (msgs || ckWARN_d(WARN_NON_UNICODE)))
2072                     {
2073                         pack_warn = packWARN(WARN_NON_UNICODE);
2074 
2075                         /* If it is an overlong that evaluates to a code point
2076                          * that doesn't have to use the Perl extended UTF-8, it
2077                          * still used it, and so we output a message that
2078                          * doesn't refer to the code point.  The same is true
2079                          * if there was a SHORT malformation where the code
2080                          * point is not valid.  In that case, 'uv' will have
2081                          * been set to the REPLACEMENT CHAR, and the message
2082                          * below without the code point in it will be selected
2083                          * */
2084                         if (UNICODE_IS_PERL_EXTENDED(uv)) {
2085                             message = Perl_form(aTHX_
2086                                             perl_extended_cp_format, uv);
2087                         }
2088                         else {
2089                             message = Perl_form(aTHX_
2090                                         "Any UTF-8 sequence that starts with"
2091                                         " \"%s\" is a Perl extension, and"
2092                                         " so is not portable",
2093                                         _byte_dump_string(s0, curlen, 0));
2094                         }
2095                         this_flag_bit = UTF8_GOT_PERL_EXTENDED;
2096                     }
2097 
2098                     if (flags & ( UTF8_WARN_PERL_EXTENDED
2099                                  |UTF8_DISALLOW_PERL_EXTENDED))
2100                     {
2101                         *errors |= UTF8_GOT_PERL_EXTENDED;
2102 
2103                         if (flags & UTF8_DISALLOW_PERL_EXTENDED) {
2104                             disallowed = TRUE;
2105                         }
2106                     }
2107                 }
2108 
2109                 if (flags & UTF8_DISALLOW_SUPER) {
2110                     *errors |= UTF8_GOT_SUPER;
2111                     disallowed = TRUE;
2112                 }
2113             }
2114             else if (possible_problems & UTF8_GOT_NONCHAR) {
2115                 possible_problems &= ~UTF8_GOT_NONCHAR;
2116 
2117                 if (flags & UTF8_WARN_NONCHAR) {
2118                     *errors |= UTF8_GOT_NONCHAR;
2119 
2120                     if (  ! (flags & UTF8_CHECK_ONLY)
2121                         && (msgs || ckWARN_d(WARN_NONCHAR)))
2122                     {
2123                         /* The code above should have guaranteed that we don't
2124                          * get here with errors other than overlong */
2125                         assert (! (orig_problems
2126                                         & ~(UTF8_GOT_LONG|UTF8_GOT_NONCHAR)));
2127 
2128                         pack_warn = packWARN(WARN_NONCHAR);
2129                         message = Perl_form(aTHX_ nonchar_cp_format, uv);
2130                         this_flag_bit = UTF8_GOT_NONCHAR;
2131                     }
2132                 }
2133 
2134                 if (flags & UTF8_DISALLOW_NONCHAR) {
2135                     disallowed = TRUE;
2136                     *errors |= UTF8_GOT_NONCHAR;
2137                 }
2138             }
2139             else if (possible_problems & UTF8_GOT_LONG) {
2140                 possible_problems &= ~UTF8_GOT_LONG;
2141                 *errors |= UTF8_GOT_LONG;
2142 
2143                 if (flags & UTF8_ALLOW_LONG) {
2144 
2145                     /* We don't allow the actual overlong value, unless the
2146                      * special extra bit is also set */
2147                     if (! (flags & (   UTF8_ALLOW_LONG_AND_ITS_VALUE
2148                                     & ~UTF8_ALLOW_LONG)))
2149                     {
2150                         uv = UNICODE_REPLACEMENT;
2151                     }
2152                 }
2153                 else {
2154                     disallowed = TRUE;
2155 
2156                     if ((   msgs
2157                          || ckWARN_d(WARN_UTF8)) && ! (flags & UTF8_CHECK_ONLY))
2158                     {
2159                         pack_warn = packWARN(WARN_UTF8);
2160 
2161                         /* These error types cause 'uv' to be something that
2162                          * isn't what was intended, so can't use it in the
2163                          * message.  The other error types either can't
2164                          * generate an overlong, or else the 'uv' is valid */
2165                         if (orig_problems &
2166                                         (UTF8_GOT_TOO_SHORT|UTF8_GOT_OVERFLOW))
2167                         {
2168                             message = Perl_form(aTHX_
2169                                     "%s: %s (any UTF-8 sequence that starts"
2170                                     " with \"%s\" is overlong which can and"
2171                                     " should be represented with a"
2172                                     " different, shorter sequence)",
2173                                     malformed_text,
2174                                     _byte_dump_string(s0, send - s0, 0),
2175                                     _byte_dump_string(s0, curlen, 0));
2176                         }
2177                         else {
2178                             U8 tmpbuf[UTF8_MAXBYTES+1];
2179                             const U8 * const e = uvoffuni_to_utf8_flags(tmpbuf,
2180                                                                         uv, 0);
2181                             /* Don't use U+ for non-Unicode code points, which
2182                              * includes those in the Latin1 range */
2183                             const char * preface = (    uv > PERL_UNICODE_MAX
2184 #ifdef EBCDIC
2185                                                      || uv <= 0xFF
2186 #endif
2187                                                     )
2188                                                    ? "0x"
2189                                                    : "U+";
2190                             message = Perl_form(aTHX_
2191                                 "%s: %s (overlong; instead use %s to represent"
2192                                 " %s%0*" UVXf ")",
2193                                 malformed_text,
2194                                 _byte_dump_string(s0, send - s0, 0),
2195                                 _byte_dump_string(tmpbuf, e - tmpbuf, 0),
2196                                 preface,
2197                                 ((uv < 256) ? 2 : 4), /* Field width of 2 for
2198                                                          small code points */
2199                                 UNI_TO_NATIVE(uv));
2200                         }
2201                         this_flag_bit = UTF8_GOT_LONG;
2202                     }
2203                 }
2204             } /* End of looking through the possible flags */
2205 
2206             /* Display the message (if any) for the problem being handled in
2207              * this iteration of the loop */
2208             if (message) {
2209                 if (msgs) {
2210                     assert(this_flag_bit);
2211 
2212                     if (*msgs == NULL) {
2213                         *msgs = newAV();
2214                     }
2215 
2216                     av_push(*msgs, newRV_noinc((SV*) new_msg_hv(message,
2217                                                                 pack_warn,
2218                                                                 this_flag_bit)));
2219                 }
2220                 else if (PL_op)
2221                     Perl_warner(aTHX_ pack_warn, "%s in %s", message,
2222                                                  OP_DESC(PL_op));
2223                 else
2224                     Perl_warner(aTHX_ pack_warn, "%s", message);
2225             }
2226         }   /* End of 'while (possible_problems)' */
2227 
2228         /* Since there was a possible problem, the returned length may need to
2229          * be changed from the one stored at the beginning of this function.
2230          * Instead of trying to figure out if that's needed, just do it. */
2231         if (retlen) {
2232             *retlen = curlen;
2233         }
2234 
2235         if (disallowed) {
2236             if (flags & UTF8_CHECK_ONLY && retlen) {
2237                 *retlen = ((STRLEN) -1);
2238             }
2239             return 0;
2240         }
2241     }
2242 
2243     return UNI_TO_NATIVE(uv);
2244 }
2245 
2246 /*
2247 =for apidoc utf8_to_uvchr_buf
2248 
2249 Returns the native code point of the first character in the string C<s> which
2250 is assumed to be in UTF-8 encoding; C<send> points to 1 beyond the end of C<s>.
2251 C<*retlen> will be set to the length, in bytes, of that character.
2252 
2253 If C<s> does not point to a well-formed UTF-8 character and UTF8 warnings are
2254 enabled, zero is returned and C<*retlen> is set (if C<retlen> isn't
2255 C<NULL>) to -1.  If those warnings are off, the computed value, if well-defined
2256 (or the Unicode REPLACEMENT CHARACTER if not), is silently returned, and
2257 C<*retlen> is set (if C<retlen> isn't C<NULL>) so that (S<C<s> + C<*retlen>>) is
2258 the next possible position in C<s> that could begin a non-malformed character.
2259 See L</utf8n_to_uvchr> for details on when the REPLACEMENT CHARACTER is
2260 returned.
2261 
2262 =cut
2263 
2264 Also implemented as a macro in utf8.h
2265 
2266 */
2267 
2268 
2269 UV
Perl_utf8_to_uvchr_buf(pTHX_ const U8 * s,const U8 * send,STRLEN * retlen)2270 Perl_utf8_to_uvchr_buf(pTHX_ const U8 *s, const U8 *send, STRLEN *retlen)
2271 {
2272     PERL_ARGS_ASSERT_UTF8_TO_UVCHR_BUF;
2273 
2274     assert(s < send);
2275 
2276     return utf8n_to_uvchr(s, send - s, retlen,
2277                      ckWARN_d(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
2278 }
2279 
2280 /* This is marked as deprecated
2281  *
2282 =for apidoc utf8_to_uvuni_buf
2283 
2284 Only in very rare circumstances should code need to be dealing in Unicode
2285 (as opposed to native) code points.  In those few cases, use
2286 C<L<NATIVE_TO_UNI(utf8_to_uvchr_buf(...))|/utf8_to_uvchr_buf>> instead.  If you
2287 are not absolutely sure this is one of those cases, then assume it isn't and
2288 use plain C<utf8_to_uvchr_buf> instead.
2289 
2290 Returns the Unicode (not-native) code point of the first character in the
2291 string C<s> which
2292 is assumed to be in UTF-8 encoding; C<send> points to 1 beyond the end of C<s>.
2293 C<retlen> will be set to the length, in bytes, of that character.
2294 
2295 If C<s> does not point to a well-formed UTF-8 character and UTF8 warnings are
2296 enabled, zero is returned and C<*retlen> is set (if C<retlen> isn't
2297 NULL) to -1.  If those warnings are off, the computed value if well-defined (or
2298 the Unicode REPLACEMENT CHARACTER, if not) is silently returned, and C<*retlen>
2299 is set (if C<retlen> isn't NULL) so that (S<C<s> + C<*retlen>>) is the
2300 next possible position in C<s> that could begin a non-malformed character.
2301 See L</utf8n_to_uvchr> for details on when the REPLACEMENT CHARACTER is returned.
2302 
2303 =cut
2304 */
2305 
2306 UV
Perl_utf8_to_uvuni_buf(pTHX_ const U8 * s,const U8 * send,STRLEN * retlen)2307 Perl_utf8_to_uvuni_buf(pTHX_ const U8 *s, const U8 *send, STRLEN *retlen)
2308 {
2309     PERL_ARGS_ASSERT_UTF8_TO_UVUNI_BUF;
2310 
2311     assert(send > s);
2312 
2313     return NATIVE_TO_UNI(utf8_to_uvchr_buf(s, send, retlen));
2314 }
2315 
2316 /*
2317 =for apidoc utf8_length
2318 
2319 Returns the number of characters in the sequence of UTF-8-encoded bytes starting
2320 at C<s> and ending at the byte just before C<e>.  If <s> and <e> point to the
2321 same place, it returns 0 with no warning raised.
2322 
2323 If C<e E<lt> s> or if the scan would end up past C<e>, it raises a UTF8 warning
2324 and returns the number of valid characters.
2325 
2326 =cut
2327 */
2328 
2329 STRLEN
Perl_utf8_length(pTHX_ const U8 * s,const U8 * e)2330 Perl_utf8_length(pTHX_ const U8 *s, const U8 *e)
2331 {
2332     STRLEN len = 0;
2333 
2334     PERL_ARGS_ASSERT_UTF8_LENGTH;
2335 
2336     /* Note: cannot use UTF8_IS_...() too eagerly here since e.g.
2337      * the bitops (especially ~) can create illegal UTF-8.
2338      * In other words: in Perl UTF-8 is not just for Unicode. */
2339 
2340     if (UNLIKELY(e < s))
2341 	goto warn_and_return;
2342     while (s < e) {
2343         s += UTF8SKIP(s);
2344 	len++;
2345     }
2346 
2347     if (UNLIKELY(e != s)) {
2348 	len--;
2349         warn_and_return:
2350 	if (PL_op)
2351 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
2352 			     "%s in %s", unees, OP_DESC(PL_op));
2353 	else
2354 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8), "%s", unees);
2355     }
2356 
2357     return len;
2358 }
2359 
2360 /*
2361 =for apidoc bytes_cmp_utf8
2362 
2363 Compares the sequence of characters (stored as octets) in C<b>, C<blen> with the
2364 sequence of characters (stored as UTF-8)
2365 in C<u>, C<ulen>.  Returns 0 if they are
2366 equal, -1 or -2 if the first string is less than the second string, +1 or +2
2367 if the first string is greater than the second string.
2368 
2369 -1 or +1 is returned if the shorter string was identical to the start of the
2370 longer string.  -2 or +2 is returned if
2371 there was a difference between characters
2372 within the strings.
2373 
2374 =cut
2375 */
2376 
2377 int
Perl_bytes_cmp_utf8(pTHX_ const U8 * b,STRLEN blen,const U8 * u,STRLEN ulen)2378 Perl_bytes_cmp_utf8(pTHX_ const U8 *b, STRLEN blen, const U8 *u, STRLEN ulen)
2379 {
2380     const U8 *const bend = b + blen;
2381     const U8 *const uend = u + ulen;
2382 
2383     PERL_ARGS_ASSERT_BYTES_CMP_UTF8;
2384 
2385     while (b < bend && u < uend) {
2386         U8 c = *u++;
2387 	if (!UTF8_IS_INVARIANT(c)) {
2388 	    if (UTF8_IS_DOWNGRADEABLE_START(c)) {
2389 		if (u < uend) {
2390 		    U8 c1 = *u++;
2391 		    if (UTF8_IS_CONTINUATION(c1)) {
2392 			c = EIGHT_BIT_UTF8_TO_NATIVE(c, c1);
2393 		    } else {
2394                         /* diag_listed_as: Malformed UTF-8 character%s */
2395 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
2396                               "%s %s%s",
2397                               unexpected_non_continuation_text(u - 2, 2, 1, 2),
2398                               PL_op ? " in " : "",
2399                               PL_op ? OP_DESC(PL_op) : "");
2400 			return -2;
2401 		    }
2402 		} else {
2403 		    if (PL_op)
2404 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
2405 					 "%s in %s", unees, OP_DESC(PL_op));
2406 		    else
2407 			Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8), "%s", unees);
2408 		    return -2; /* Really want to return undef :-)  */
2409 		}
2410 	    } else {
2411 		return -2;
2412 	    }
2413 	}
2414 	if (*b != c) {
2415 	    return *b < c ? -2 : +2;
2416 	}
2417 	++b;
2418     }
2419 
2420     if (b == bend && u == uend)
2421 	return 0;
2422 
2423     return b < bend ? +1 : -1;
2424 }
2425 
2426 /*
2427 =for apidoc utf8_to_bytes
2428 
2429 Converts a string C<"s"> of length C<*lenp> from UTF-8 into native byte encoding.
2430 Unlike L</bytes_to_utf8>, this over-writes the original string, and
2431 updates C<*lenp> to contain the new length.
2432 Returns zero on failure (leaving C<"s"> unchanged) setting C<*lenp> to -1.
2433 
2434 Upon successful return, the number of variants in the string can be computed by
2435 having saved the value of C<*lenp> before the call, and subtracting the
2436 after-call value of C<*lenp> from it.
2437 
2438 If you need a copy of the string, see L</bytes_from_utf8>.
2439 
2440 =cut
2441 */
2442 
2443 U8 *
Perl_utf8_to_bytes(pTHX_ U8 * s,STRLEN * lenp)2444 Perl_utf8_to_bytes(pTHX_ U8 *s, STRLEN *lenp)
2445 {
2446     U8 * first_variant;
2447 
2448     PERL_ARGS_ASSERT_UTF8_TO_BYTES;
2449     PERL_UNUSED_CONTEXT;
2450 
2451     /* This is a no-op if no variants at all in the input */
2452     if (is_utf8_invariant_string_loc(s, *lenp, (const U8 **) &first_variant)) {
2453         return s;
2454     }
2455 
2456     {
2457         U8 * const save = s;
2458         U8 * const send = s + *lenp;
2459         U8 * d;
2460 
2461         /* Nothing before the first variant needs to be changed, so start the real
2462          * work there */
2463         s = first_variant;
2464         while (s < send) {
2465             if (! UTF8_IS_INVARIANT(*s)) {
2466                 if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s, send)) {
2467                     *lenp = ((STRLEN) -1);
2468                     return 0;
2469                 }
2470                 s++;
2471             }
2472             s++;
2473         }
2474 
2475         /* Is downgradable, so do it */
2476         d = s = first_variant;
2477         while (s < send) {
2478             U8 c = *s++;
2479             if (! UVCHR_IS_INVARIANT(c)) {
2480                 /* Then it is two-byte encoded */
2481                 c = EIGHT_BIT_UTF8_TO_NATIVE(c, *s);
2482                 s++;
2483             }
2484             *d++ = c;
2485         }
2486         *d = '\0';
2487         *lenp = d - save;
2488 
2489         return save;
2490     }
2491 }
2492 
2493 /*
2494 =for apidoc bytes_from_utf8
2495 
2496 Converts a potentially UTF-8 encoded string C<s> of length C<*lenp> into native
2497 byte encoding.  On input, the boolean C<*is_utf8p> gives whether or not C<s> is
2498 actually encoded in UTF-8.
2499 
2500 Unlike L</utf8_to_bytes> but like L</bytes_to_utf8>, this is non-destructive of
2501 the input string.
2502 
2503 Do nothing if C<*is_utf8p> is 0, or if there are code points in the string
2504 not expressible in native byte encoding.  In these cases, C<*is_utf8p> and
2505 C<*lenp> are unchanged, and the return value is the original C<s>.
2506 
2507 Otherwise, C<*is_utf8p> is set to 0, and the return value is a pointer to a
2508 newly created string containing a downgraded copy of C<s>, and whose length is
2509 returned in C<*lenp>, updated.  The new string is C<NUL>-terminated.  The
2510 caller is responsible for arranging for the memory used by this string to get
2511 freed.
2512 
2513 Upon successful return, the number of variants in the string can be computed by
2514 having saved the value of C<*lenp> before the call, and subtracting the
2515 after-call value of C<*lenp> from it.
2516 
2517 =cut
2518 
2519 There is a macro that avoids this function call, but this is retained for
2520 anyone who calls it with the Perl_ prefix */
2521 
2522 U8 *
Perl_bytes_from_utf8(pTHX_ const U8 * s,STRLEN * lenp,bool * is_utf8p)2523 Perl_bytes_from_utf8(pTHX_ const U8 *s, STRLEN *lenp, bool *is_utf8p)
2524 {
2525     PERL_ARGS_ASSERT_BYTES_FROM_UTF8;
2526     PERL_UNUSED_CONTEXT;
2527 
2528     return bytes_from_utf8_loc(s, lenp, is_utf8p, NULL);
2529 }
2530 
2531 /*
2532 No = here because currently externally undocumented
2533 for apidoc bytes_from_utf8_loc
2534 
2535 Like C<L</bytes_from_utf8>()>, but takes an extra parameter, a pointer to where
2536 to store the location of the first character in C<"s"> that cannot be
2537 converted to non-UTF8.
2538 
2539 If that parameter is C<NULL>, this function behaves identically to
2540 C<bytes_from_utf8>.
2541 
2542 Otherwise if C<*is_utf8p> is 0 on input, the function behaves identically to
2543 C<bytes_from_utf8>, except it also sets C<*first_non_downgradable> to C<NULL>.
2544 
2545 Otherwise, the function returns a newly created C<NUL>-terminated string
2546 containing the non-UTF8 equivalent of the convertible first portion of
2547 C<"s">.  C<*lenp> is set to its length, not including the terminating C<NUL>.
2548 If the entire input string was converted, C<*is_utf8p> is set to a FALSE value,
2549 and C<*first_non_downgradable> is set to C<NULL>.
2550 
2551 Otherwise, C<*first_non_downgradable> set to point to the first byte of the
2552 first character in the original string that wasn't converted.  C<*is_utf8p> is
2553 unchanged.  Note that the new string may have length 0.
2554 
2555 Another way to look at it is, if C<*first_non_downgradable> is non-C<NULL> and
2556 C<*is_utf8p> is TRUE, this function starts at the beginning of C<"s"> and
2557 converts as many characters in it as possible stopping at the first one it
2558 finds that can't be converted to non-UTF-8.  C<*first_non_downgradable> is
2559 set to point to that.  The function returns the portion that could be converted
2560 in a newly created C<NUL>-terminated string, and C<*lenp> is set to its length,
2561 not including the terminating C<NUL>.  If the very first character in the
2562 original could not be converted, C<*lenp> will be 0, and the new string will
2563 contain just a single C<NUL>.  If the entire input string was converted,
2564 C<*is_utf8p> is set to FALSE and C<*first_non_downgradable> is set to C<NULL>.
2565 
2566 Upon successful return, the number of variants in the converted portion of the
2567 string can be computed by having saved the value of C<*lenp> before the call,
2568 and subtracting the after-call value of C<*lenp> from it.
2569 
2570 =cut
2571 
2572 
2573 */
2574 
2575 U8 *
Perl_bytes_from_utf8_loc(const U8 * s,STRLEN * lenp,bool * is_utf8p,const U8 ** first_unconverted)2576 Perl_bytes_from_utf8_loc(const U8 *s, STRLEN *lenp, bool *is_utf8p, const U8** first_unconverted)
2577 {
2578     U8 *d;
2579     const U8 *original = s;
2580     U8 *converted_start;
2581     const U8 *send = s + *lenp;
2582 
2583     PERL_ARGS_ASSERT_BYTES_FROM_UTF8_LOC;
2584 
2585     if (! *is_utf8p) {
2586         if (first_unconverted) {
2587             *first_unconverted = NULL;
2588         }
2589 
2590         return (U8 *) original;
2591     }
2592 
2593     Newx(d, (*lenp) + 1, U8);
2594 
2595     converted_start = d;
2596     while (s < send) {
2597         U8 c = *s++;
2598         if (! UTF8_IS_INVARIANT(c)) {
2599 
2600             /* Then it is multi-byte encoded.  If the code point is above 0xFF,
2601              * have to stop now */
2602             if (UNLIKELY (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s - 1, send))) {
2603                 if (first_unconverted) {
2604                     *first_unconverted = s - 1;
2605                     goto finish_and_return;
2606                 }
2607                 else {
2608                     Safefree(converted_start);
2609                     return (U8 *) original;
2610                 }
2611             }
2612 
2613             c = EIGHT_BIT_UTF8_TO_NATIVE(c, *s);
2614             s++;
2615         }
2616         *d++ = c;
2617     }
2618 
2619     /* Here, converted the whole of the input */
2620     *is_utf8p = FALSE;
2621     if (first_unconverted) {
2622         *first_unconverted = NULL;
2623     }
2624 
2625   finish_and_return:
2626     *d = '\0';
2627     *lenp = d - converted_start;
2628 
2629     /* Trim unused space */
2630     Renew(converted_start, *lenp + 1, U8);
2631 
2632     return converted_start;
2633 }
2634 
2635 /*
2636 =for apidoc bytes_to_utf8
2637 
2638 Converts a string C<s> of length C<*lenp> bytes from the native encoding into
2639 UTF-8.
2640 Returns a pointer to the newly-created string, and sets C<*lenp> to
2641 reflect the new length in bytes.  The caller is responsible for arranging for
2642 the memory used by this string to get freed.
2643 
2644 Upon successful return, the number of variants in the string can be computed by
2645 having saved the value of C<*lenp> before the call, and subtracting it from the
2646 after-call value of C<*lenp>.
2647 
2648 A C<NUL> character will be written after the end of the string.
2649 
2650 If you want to convert to UTF-8 from encodings other than
2651 the native (Latin1 or EBCDIC),
2652 see L</sv_recode_to_utf8>().
2653 
2654 =cut
2655 */
2656 
2657 U8*
Perl_bytes_to_utf8(pTHX_ const U8 * s,STRLEN * lenp)2658 Perl_bytes_to_utf8(pTHX_ const U8 *s, STRLEN *lenp)
2659 {
2660     const U8 * const send = s + (*lenp);
2661     U8 *d;
2662     U8 *dst;
2663 
2664     PERL_ARGS_ASSERT_BYTES_TO_UTF8;
2665     PERL_UNUSED_CONTEXT;
2666 
2667     /* 1 for each byte + 1 for each byte that expands to two, + trailing NUL */
2668     Newx(d, (*lenp) + variant_under_utf8_count(s, send) + 1, U8);
2669     dst = d;
2670 
2671     while (s < send) {
2672         append_utf8_from_native_byte(*s, &d);
2673         s++;
2674     }
2675 
2676     *d = '\0';
2677     *lenp = d-dst;
2678 
2679     return dst;
2680 }
2681 
2682 /*
2683  * Convert native (big-endian) UTF-16 to UTF-8.  For reversed (little-endian),
2684  * use utf16_to_utf8_reversed().
2685  *
2686  * UTF-16 requires 2 bytes for every code point below 0x10000; otherwise 4 bytes.
2687  * UTF-8 requires 1-3 bytes for every code point below 0x1000; otherwise 4 bytes.
2688  * UTF-EBCDIC requires 1-4 bytes for every code point below 0x1000; otherwise 4-5 bytes.
2689  *
2690  * These functions don't check for overflow.  The worst case is every code
2691  * point in the input is 2 bytes, and requires 4 bytes on output.  (If the code
2692  * is never going to run in EBCDIC, it is 2 bytes requiring 3 on output.)  Therefore the
2693  * destination must be pre-extended to 2 times the source length.
2694  *
2695  * Do not use in-place.  We optimize for native, for obvious reasons. */
2696 
2697 U8*
Perl_utf16_to_utf8(pTHX_ U8 * p,U8 * d,I32 bytelen,I32 * newlen)2698 Perl_utf16_to_utf8(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
2699 {
2700     U8* pend;
2701     U8* dstart = d;
2702 
2703     PERL_ARGS_ASSERT_UTF16_TO_UTF8;
2704 
2705     if (bytelen & 1)
2706 	Perl_croak(aTHX_ "panic: utf16_to_utf8: odd bytelen %" UVuf,
2707                                                                (UV)bytelen);
2708 
2709     pend = p + bytelen;
2710 
2711     while (p < pend) {
2712 	UV uv = (p[0] << 8) + p[1]; /* UTF-16BE */
2713 	p += 2;
2714 	if (OFFUNI_IS_INVARIANT(uv)) {
2715 	    *d++ = LATIN1_TO_NATIVE((U8) uv);
2716 	    continue;
2717 	}
2718 	if (uv <= MAX_UTF8_TWO_BYTE) {
2719 	    *d++ = UTF8_TWO_BYTE_HI(UNI_TO_NATIVE(uv));
2720 	    *d++ = UTF8_TWO_BYTE_LO(UNI_TO_NATIVE(uv));
2721 	    continue;
2722 	}
2723 
2724 #define FIRST_HIGH_SURROGATE UNICODE_SURROGATE_FIRST
2725 #define LAST_HIGH_SURROGATE  0xDBFF
2726 #define FIRST_LOW_SURROGATE  0xDC00
2727 #define LAST_LOW_SURROGATE   UNICODE_SURROGATE_LAST
2728 #define FIRST_IN_PLANE1      0x10000
2729 
2730         /* This assumes that most uses will be in the first Unicode plane, not
2731          * needing surrogates */
2732 	if (UNLIKELY(uv >= UNICODE_SURROGATE_FIRST
2733                   && uv <= UNICODE_SURROGATE_LAST))
2734         {
2735             if (UNLIKELY(p >= pend) || UNLIKELY(uv > LAST_HIGH_SURROGATE)) {
2736                 Perl_croak(aTHX_ "Malformed UTF-16 surrogate");
2737             }
2738 	    else {
2739 		UV low = (p[0] << 8) + p[1];
2740 		if (   UNLIKELY(low < FIRST_LOW_SURROGATE)
2741                     || UNLIKELY(low > LAST_LOW_SURROGATE))
2742                 {
2743 		    Perl_croak(aTHX_ "Malformed UTF-16 surrogate");
2744                 }
2745 		p += 2;
2746 		uv = ((uv - FIRST_HIGH_SURROGATE) << 10)
2747                                 + (low - FIRST_LOW_SURROGATE) + FIRST_IN_PLANE1;
2748 	    }
2749 	}
2750 #ifdef EBCDIC
2751         d = uvoffuni_to_utf8_flags(d, uv, 0);
2752 #else
2753 	if (uv < FIRST_IN_PLANE1) {
2754 	    *d++ = (U8)(( uv >> 12)         | 0xe0);
2755 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
2756 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
2757 	    continue;
2758 	}
2759 	else {
2760 	    *d++ = (U8)(( uv >> 18)         | 0xf0);
2761 	    *d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
2762 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
2763 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
2764 	    continue;
2765 	}
2766 #endif
2767     }
2768     *newlen = d - dstart;
2769     return d;
2770 }
2771 
2772 /* Note: this one is slightly destructive of the source. */
2773 
2774 U8*
Perl_utf16_to_utf8_reversed(pTHX_ U8 * p,U8 * d,I32 bytelen,I32 * newlen)2775 Perl_utf16_to_utf8_reversed(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
2776 {
2777     U8* s = (U8*)p;
2778     U8* const send = s + bytelen;
2779 
2780     PERL_ARGS_ASSERT_UTF16_TO_UTF8_REVERSED;
2781 
2782     if (bytelen & 1)
2783 	Perl_croak(aTHX_ "panic: utf16_to_utf8_reversed: odd bytelen %" UVuf,
2784 		   (UV)bytelen);
2785 
2786     while (s < send) {
2787 	const U8 tmp = s[0];
2788 	s[0] = s[1];
2789 	s[1] = tmp;
2790 	s += 2;
2791     }
2792     return utf16_to_utf8(p, d, bytelen, newlen);
2793 }
2794 
2795 bool
Perl__is_uni_FOO(pTHX_ const U8 classnum,const UV c)2796 Perl__is_uni_FOO(pTHX_ const U8 classnum, const UV c)
2797 {
2798     dVAR;
2799     return _invlist_contains_cp(PL_XPosix_ptrs[classnum], c);
2800 }
2801 
2802 /* Internal function so we can deprecate the external one, and call
2803    this one from other deprecated functions in this file */
2804 
2805 bool
Perl__is_utf8_idstart(pTHX_ const U8 * p)2806 Perl__is_utf8_idstart(pTHX_ const U8 *p)
2807 {
2808     dVAR;
2809 
2810     PERL_ARGS_ASSERT__IS_UTF8_IDSTART;
2811 
2812     if (*p == '_')
2813 	return TRUE;
2814     return is_utf8_common(p, PL_utf8_idstart);
2815 }
2816 
2817 bool
Perl__is_uni_perl_idcont(pTHX_ UV c)2818 Perl__is_uni_perl_idcont(pTHX_ UV c)
2819 {
2820     dVAR;
2821     return _invlist_contains_cp(PL_utf8_perl_idcont, c);
2822 }
2823 
2824 bool
Perl__is_uni_perl_idstart(pTHX_ UV c)2825 Perl__is_uni_perl_idstart(pTHX_ UV c)
2826 {
2827     dVAR;
2828     return _invlist_contains_cp(PL_utf8_perl_idstart, c);
2829 }
2830 
2831 UV
Perl__to_upper_title_latin1(pTHX_ const U8 c,U8 * p,STRLEN * lenp,const char S_or_s)2832 Perl__to_upper_title_latin1(pTHX_ const U8 c, U8* p, STRLEN *lenp,
2833                                   const char S_or_s)
2834 {
2835     /* We have the latin1-range values compiled into the core, so just use
2836      * those, converting the result to UTF-8.  The only difference between upper
2837      * and title case in this range is that LATIN_SMALL_LETTER_SHARP_S is
2838      * either "SS" or "Ss".  Which one to use is passed into the routine in
2839      * 'S_or_s' to avoid a test */
2840 
2841     UV converted = toUPPER_LATIN1_MOD(c);
2842 
2843     PERL_ARGS_ASSERT__TO_UPPER_TITLE_LATIN1;
2844 
2845     assert(S_or_s == 'S' || S_or_s == 's');
2846 
2847     if (UVCHR_IS_INVARIANT(converted)) { /* No difference between the two for
2848 					     characters in this range */
2849 	*p = (U8) converted;
2850 	*lenp = 1;
2851 	return converted;
2852     }
2853 
2854     /* toUPPER_LATIN1_MOD gives the correct results except for three outliers,
2855      * which it maps to one of them, so as to only have to have one check for
2856      * it in the main case */
2857     if (UNLIKELY(converted == LATIN_SMALL_LETTER_Y_WITH_DIAERESIS)) {
2858 	switch (c) {
2859 	    case LATIN_SMALL_LETTER_Y_WITH_DIAERESIS:
2860 		converted = LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS;
2861 		break;
2862 	    case MICRO_SIGN:
2863 		converted = GREEK_CAPITAL_LETTER_MU;
2864 		break;
2865 #if    UNICODE_MAJOR_VERSION > 2                                        \
2866    || (UNICODE_MAJOR_VERSION == 2 && UNICODE_DOT_VERSION >= 1           \
2867                                   && UNICODE_DOT_DOT_VERSION >= 8)
2868 	    case LATIN_SMALL_LETTER_SHARP_S:
2869 		*(p)++ = 'S';
2870 		*p = S_or_s;
2871 		*lenp = 2;
2872 		return 'S';
2873 #endif
2874 	    default:
2875 		Perl_croak(aTHX_ "panic: to_upper_title_latin1 did not expect"
2876                                  " '%c' to map to '%c'",
2877                                  c, LATIN_SMALL_LETTER_Y_WITH_DIAERESIS);
2878 		NOT_REACHED; /* NOTREACHED */
2879 	}
2880     }
2881 
2882     *(p)++ = UTF8_TWO_BYTE_HI(converted);
2883     *p = UTF8_TWO_BYTE_LO(converted);
2884     *lenp = 2;
2885 
2886     return converted;
2887 }
2888 
2889 /* If compiled on an early Unicode version, there may not be auxiliary tables
2890  * */
2891 #ifndef HAS_UC_AUX_TABLES
2892 #  define UC_AUX_TABLE_ptrs     NULL
2893 #  define UC_AUX_TABLE_lengths  NULL
2894 #endif
2895 #ifndef HAS_TC_AUX_TABLES
2896 #  define TC_AUX_TABLE_ptrs     NULL
2897 #  define TC_AUX_TABLE_lengths  NULL
2898 #endif
2899 #ifndef HAS_LC_AUX_TABLES
2900 #  define LC_AUX_TABLE_ptrs     NULL
2901 #  define LC_AUX_TABLE_lengths  NULL
2902 #endif
2903 #ifndef HAS_CF_AUX_TABLES
2904 #  define CF_AUX_TABLE_ptrs     NULL
2905 #  define CF_AUX_TABLE_lengths  NULL
2906 #endif
2907 #ifndef HAS_UC_AUX_TABLES
2908 #  define UC_AUX_TABLE_ptrs     NULL
2909 #  define UC_AUX_TABLE_lengths  NULL
2910 #endif
2911 
2912 /* Call the function to convert a UTF-8 encoded character to the specified case.
2913  * Note that there may be more than one character in the result.
2914  * 's' is a pointer to the first byte of the input character
2915  * 'd' will be set to the first byte of the string of changed characters.  It
2916  *	needs to have space for UTF8_MAXBYTES_CASE+1 bytes
2917  * 'lenp' will be set to the length in bytes of the string of changed characters
2918  *
2919  * The functions return the ordinal of the first character in the string of
2920  * 'd' */
2921 #define CALL_UPPER_CASE(uv, s, d, lenp)                                     \
2922                 _to_utf8_case(uv, s, d, lenp, PL_utf8_toupper,              \
2923                                               Uppercase_Mapping_invmap,     \
2924                                               UC_AUX_TABLE_ptrs,            \
2925                                               UC_AUX_TABLE_lengths,         \
2926                                               "uppercase")
2927 #define CALL_TITLE_CASE(uv, s, d, lenp)                                     \
2928                 _to_utf8_case(uv, s, d, lenp, PL_utf8_totitle,              \
2929                                               Titlecase_Mapping_invmap,     \
2930                                               TC_AUX_TABLE_ptrs,            \
2931                                               TC_AUX_TABLE_lengths,         \
2932                                               "titlecase")
2933 #define CALL_LOWER_CASE(uv, s, d, lenp)                                     \
2934                 _to_utf8_case(uv, s, d, lenp, PL_utf8_tolower,              \
2935                                               Lowercase_Mapping_invmap,     \
2936                                               LC_AUX_TABLE_ptrs,            \
2937                                               LC_AUX_TABLE_lengths,         \
2938                                               "lowercase")
2939 
2940 
2941 /* This additionally has the input parameter 'specials', which if non-zero will
2942  * cause this to use the specials hash for folding (meaning get full case
2943  * folding); otherwise, when zero, this implies a simple case fold */
2944 #define CALL_FOLD_CASE(uv, s, d, lenp, specials)                            \
2945         (specials)                                                          \
2946         ?  _to_utf8_case(uv, s, d, lenp, PL_utf8_tofold,                    \
2947                                           Case_Folding_invmap,              \
2948                                           CF_AUX_TABLE_ptrs,                \
2949                                           CF_AUX_TABLE_lengths,             \
2950                                           "foldcase")                       \
2951         : _to_utf8_case(uv, s, d, lenp, PL_utf8_tosimplefold,               \
2952                                          Simple_Case_Folding_invmap,        \
2953                                          NULL, NULL,                        \
2954                                          "foldcase")
2955 
2956 UV
Perl_to_uni_upper(pTHX_ UV c,U8 * p,STRLEN * lenp)2957 Perl_to_uni_upper(pTHX_ UV c, U8* p, STRLEN *lenp)
2958 {
2959     /* Convert the Unicode character whose ordinal is <c> to its uppercase
2960      * version and store that in UTF-8 in <p> and its length in bytes in <lenp>.
2961      * Note that the <p> needs to be at least UTF8_MAXBYTES_CASE+1 bytes since
2962      * the changed version may be longer than the original character.
2963      *
2964      * The ordinal of the first character of the changed version is returned
2965      * (but note, as explained above, that there may be more.) */
2966 
2967     dVAR;
2968     PERL_ARGS_ASSERT_TO_UNI_UPPER;
2969 
2970     if (c < 256) {
2971 	return _to_upper_title_latin1((U8) c, p, lenp, 'S');
2972     }
2973 
2974     return CALL_UPPER_CASE(c, NULL, p, lenp);
2975 }
2976 
2977 UV
Perl_to_uni_title(pTHX_ UV c,U8 * p,STRLEN * lenp)2978 Perl_to_uni_title(pTHX_ UV c, U8* p, STRLEN *lenp)
2979 {
2980     dVAR;
2981     PERL_ARGS_ASSERT_TO_UNI_TITLE;
2982 
2983     if (c < 256) {
2984 	return _to_upper_title_latin1((U8) c, p, lenp, 's');
2985     }
2986 
2987     return CALL_TITLE_CASE(c, NULL, p, lenp);
2988 }
2989 
2990 STATIC U8
S_to_lower_latin1(const U8 c,U8 * p,STRLEN * lenp,const char dummy)2991 S_to_lower_latin1(const U8 c, U8* p, STRLEN *lenp, const char dummy)
2992 {
2993     /* We have the latin1-range values compiled into the core, so just use
2994      * those, converting the result to UTF-8.  Since the result is always just
2995      * one character, we allow <p> to be NULL */
2996 
2997     U8 converted = toLOWER_LATIN1(c);
2998 
2999     PERL_UNUSED_ARG(dummy);
3000 
3001     if (p != NULL) {
3002 	if (NATIVE_BYTE_IS_INVARIANT(converted)) {
3003 	    *p = converted;
3004 	    *lenp = 1;
3005 	}
3006 	else {
3007             /* Result is known to always be < 256, so can use the EIGHT_BIT
3008              * macros */
3009 	    *p = UTF8_EIGHT_BIT_HI(converted);
3010 	    *(p+1) = UTF8_EIGHT_BIT_LO(converted);
3011 	    *lenp = 2;
3012 	}
3013     }
3014     return converted;
3015 }
3016 
3017 UV
Perl_to_uni_lower(pTHX_ UV c,U8 * p,STRLEN * lenp)3018 Perl_to_uni_lower(pTHX_ UV c, U8* p, STRLEN *lenp)
3019 {
3020     dVAR;
3021     PERL_ARGS_ASSERT_TO_UNI_LOWER;
3022 
3023     if (c < 256) {
3024 	return to_lower_latin1((U8) c, p, lenp, 0 /* 0 is a dummy arg */ );
3025     }
3026 
3027     return CALL_LOWER_CASE(c, NULL, p, lenp);
3028 }
3029 
3030 UV
Perl__to_fold_latin1(const U8 c,U8 * p,STRLEN * lenp,const unsigned int flags)3031 Perl__to_fold_latin1(const U8 c, U8* p, STRLEN *lenp, const unsigned int flags)
3032 {
3033     /* Corresponds to to_lower_latin1(); <flags> bits meanings:
3034      *	    FOLD_FLAGS_NOMIX_ASCII iff non-ASCII to ASCII folds are prohibited
3035      *	    FOLD_FLAGS_FULL  iff full folding is to be used;
3036      *
3037      *	Not to be used for locale folds
3038      */
3039 
3040     UV converted;
3041 
3042     PERL_ARGS_ASSERT__TO_FOLD_LATIN1;
3043 
3044     assert (! (flags & FOLD_FLAGS_LOCALE));
3045 
3046     if (UNLIKELY(c == MICRO_SIGN)) {
3047 	converted = GREEK_SMALL_LETTER_MU;
3048     }
3049 #if    UNICODE_MAJOR_VERSION > 3 /* no multifolds in early Unicode */   \
3050    || (UNICODE_MAJOR_VERSION == 3 && (   UNICODE_DOT_VERSION > 0)       \
3051                                       || UNICODE_DOT_DOT_VERSION > 0)
3052     else if (   (flags & FOLD_FLAGS_FULL)
3053              && UNLIKELY(c == LATIN_SMALL_LETTER_SHARP_S))
3054     {
3055         /* If can't cross 127/128 boundary, can't return "ss"; instead return
3056          * two U+017F characters, as fc("\df") should eq fc("\x{17f}\x{17f}")
3057          * under those circumstances. */
3058         if (flags & FOLD_FLAGS_NOMIX_ASCII) {
3059             *lenp = 2 * sizeof(LATIN_SMALL_LETTER_LONG_S_UTF8) - 2;
3060             Copy(LATIN_SMALL_LETTER_LONG_S_UTF8 LATIN_SMALL_LETTER_LONG_S_UTF8,
3061                  p, *lenp, U8);
3062             return LATIN_SMALL_LETTER_LONG_S;
3063         }
3064         else {
3065             *(p)++ = 's';
3066             *p = 's';
3067             *lenp = 2;
3068             return 's';
3069         }
3070     }
3071 #endif
3072     else { /* In this range the fold of all other characters is their lower
3073               case */
3074 	converted = toLOWER_LATIN1(c);
3075     }
3076 
3077     if (UVCHR_IS_INVARIANT(converted)) {
3078 	*p = (U8) converted;
3079 	*lenp = 1;
3080     }
3081     else {
3082 	*(p)++ = UTF8_TWO_BYTE_HI(converted);
3083 	*p = UTF8_TWO_BYTE_LO(converted);
3084 	*lenp = 2;
3085     }
3086 
3087     return converted;
3088 }
3089 
3090 UV
Perl__to_uni_fold_flags(pTHX_ UV c,U8 * p,STRLEN * lenp,U8 flags)3091 Perl__to_uni_fold_flags(pTHX_ UV c, U8* p, STRLEN *lenp, U8 flags)
3092 {
3093 
3094     /* Not currently externally documented, and subject to change
3095      *  <flags> bits meanings:
3096      *	    FOLD_FLAGS_FULL  iff full folding is to be used;
3097      *	    FOLD_FLAGS_LOCALE is set iff the rules from the current underlying
3098      *	                      locale are to be used.
3099      *	    FOLD_FLAGS_NOMIX_ASCII iff non-ASCII to ASCII folds are prohibited
3100      */
3101 
3102     dVAR;
3103     PERL_ARGS_ASSERT__TO_UNI_FOLD_FLAGS;
3104 
3105     if (flags & FOLD_FLAGS_LOCALE) {
3106         /* Treat a non-Turkic UTF-8 locale as not being in locale at all,
3107          * except for potentially warning */
3108         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
3109         if (IN_UTF8_CTYPE_LOCALE && ! PL_in_utf8_turkic_locale) {
3110             flags &= ~FOLD_FLAGS_LOCALE;
3111         }
3112         else {
3113             goto needs_full_generality;
3114         }
3115     }
3116 
3117     if (c < 256) {
3118         return _to_fold_latin1((U8) c, p, lenp,
3119 			    flags & (FOLD_FLAGS_FULL | FOLD_FLAGS_NOMIX_ASCII));
3120     }
3121 
3122     /* Here, above 255.  If no special needs, just use the macro */
3123     if ( ! (flags & (FOLD_FLAGS_LOCALE|FOLD_FLAGS_NOMIX_ASCII))) {
3124 	return CALL_FOLD_CASE(c, NULL, p, lenp, flags & FOLD_FLAGS_FULL);
3125     }
3126     else {  /* Otherwise, _toFOLD_utf8_flags has the intelligence to deal with
3127 	       the special flags. */
3128 	U8 utf8_c[UTF8_MAXBYTES + 1];
3129 
3130       needs_full_generality:
3131 	uvchr_to_utf8(utf8_c, c);
3132 	return _toFOLD_utf8_flags(utf8_c, utf8_c + sizeof(utf8_c),
3133                                   p, lenp, flags);
3134     }
3135 }
3136 
3137 PERL_STATIC_INLINE bool
S_is_utf8_common(pTHX_ const U8 * const p,SV * const invlist)3138 S_is_utf8_common(pTHX_ const U8 *const p, SV* const invlist)
3139 {
3140     /* returns a boolean giving whether or not the UTF8-encoded character that
3141      * starts at <p> is in the inversion list indicated by <invlist>.
3142      *
3143      * Note that it is assumed that the buffer length of <p> is enough to
3144      * contain all the bytes that comprise the character.  Thus, <*p> should
3145      * have been checked before this call for mal-formedness enough to assure
3146      * that.  This function, does make sure to not look past any NUL, so it is
3147      * safe to use on C, NUL-terminated, strings */
3148     STRLEN len = my_strnlen((char *) p, UTF8SKIP(p));
3149 
3150     PERL_ARGS_ASSERT_IS_UTF8_COMMON;
3151 
3152     /* The API should have included a length for the UTF-8 character in <p>,
3153      * but it doesn't.  We therefore assume that p has been validated at least
3154      * as far as there being enough bytes available in it to accommodate the
3155      * character without reading beyond the end, and pass that number on to the
3156      * validating routine */
3157     if (! isUTF8_CHAR(p, p + len)) {
3158         _force_out_malformed_utf8_message(p, p + len, _UTF8_NO_CONFIDENCE_IN_CURLEN,
3159                                           1 /* Die */ );
3160         NOT_REACHED; /* NOTREACHED */
3161     }
3162 
3163     return is_utf8_common_with_len(p, p + len, invlist);
3164 }
3165 
3166 PERL_STATIC_INLINE bool
S_is_utf8_common_with_len(pTHX_ const U8 * const p,const U8 * const e,SV * const invlist)3167 S_is_utf8_common_with_len(pTHX_ const U8 *const p, const U8 * const e,
3168                           SV* const invlist)
3169 {
3170     /* returns a boolean giving whether or not the UTF8-encoded character that
3171      * starts at <p>, and extending no further than <e - 1> is in the inversion
3172      * list <invlist>. */
3173 
3174     UV cp = utf8n_to_uvchr(p, e - p, NULL, 0);
3175 
3176     PERL_ARGS_ASSERT_IS_UTF8_COMMON_WITH_LEN;
3177 
3178     if (cp == 0 && (p >= e || *p != '\0')) {
3179         _force_out_malformed_utf8_message(p, e, 0, 1);
3180         NOT_REACHED; /* NOTREACHED */
3181     }
3182 
3183     assert(invlist);
3184     return _invlist_contains_cp(invlist, cp);
3185 }
3186 
3187 STATIC void
S_warn_on_first_deprecated_use(pTHX_ const char * const name,const char * const alternative,const bool use_locale,const char * const file,const unsigned line)3188 S_warn_on_first_deprecated_use(pTHX_ const char * const name,
3189                                      const char * const alternative,
3190                                      const bool use_locale,
3191                                      const char * const file,
3192                                      const unsigned line)
3193 {
3194     const char * key;
3195 
3196     PERL_ARGS_ASSERT_WARN_ON_FIRST_DEPRECATED_USE;
3197 
3198     if (ckWARN_d(WARN_DEPRECATED)) {
3199 
3200         key = Perl_form(aTHX_ "%s;%d;%s;%d", name, use_locale, file, line);
3201 	if (! hv_fetch(PL_seen_deprecated_macro, key, strlen(key), 0)) {
3202             if (! PL_seen_deprecated_macro) {
3203                 PL_seen_deprecated_macro = newHV();
3204             }
3205             if (! hv_store(PL_seen_deprecated_macro, key,
3206                            strlen(key), &PL_sv_undef, 0))
3207             {
3208 		Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed");
3209             }
3210 
3211             if (instr(file, "mathoms.c")) {
3212                 Perl_warner(aTHX_ WARN_DEPRECATED,
3213                             "In %s, line %d, starting in Perl v5.32, %s()"
3214                             " will be removed.  Avoid this message by"
3215                             " converting to use %s().\n",
3216                             file, line, name, alternative);
3217             }
3218             else {
3219                 Perl_warner(aTHX_ WARN_DEPRECATED,
3220                             "In %s, line %d, starting in Perl v5.32, %s() will"
3221                             " require an additional parameter.  Avoid this"
3222                             " message by converting to use %s().\n",
3223                             file, line, name, alternative);
3224             }
3225         }
3226     }
3227 }
3228 
3229 bool
Perl__is_utf8_FOO(pTHX_ U8 classnum,const U8 * const p,const char * const name,const char * const alternative,const bool use_utf8,const bool use_locale,const char * const file,const unsigned line)3230 Perl__is_utf8_FOO(pTHX_       U8   classnum,
3231                         const U8   * const p,
3232                         const char * const name,
3233                         const char * const alternative,
3234                         const bool use_utf8,
3235                         const bool use_locale,
3236                         const char * const file,
3237                         const unsigned line)
3238 {
3239     dVAR;
3240     PERL_ARGS_ASSERT__IS_UTF8_FOO;
3241 
3242     warn_on_first_deprecated_use(name, alternative, use_locale, file, line);
3243 
3244     if (use_utf8 && UTF8_IS_ABOVE_LATIN1(*p)) {
3245 
3246         switch (classnum) {
3247             case _CC_WORDCHAR:
3248             case _CC_DIGIT:
3249             case _CC_ALPHA:
3250             case _CC_LOWER:
3251             case _CC_UPPER:
3252             case _CC_PUNCT:
3253             case _CC_PRINT:
3254             case _CC_ALPHANUMERIC:
3255             case _CC_GRAPH:
3256             case _CC_CASED:
3257 
3258                 return is_utf8_common(p, PL_XPosix_ptrs[classnum]);
3259 
3260             case _CC_SPACE:
3261                 return is_XPERLSPACE_high(p);
3262             case _CC_BLANK:
3263                 return is_HORIZWS_high(p);
3264             case _CC_XDIGIT:
3265                 return is_XDIGIT_high(p);
3266             case _CC_CNTRL:
3267                 return 0;
3268             case _CC_ASCII:
3269                 return 0;
3270             case _CC_VERTSPACE:
3271                 return is_VERTWS_high(p);
3272             case _CC_IDFIRST:
3273                 return is_utf8_common(p, PL_utf8_perl_idstart);
3274             case _CC_IDCONT:
3275                 return is_utf8_common(p, PL_utf8_perl_idcont);
3276         }
3277     }
3278 
3279     /* idcont is the same as wordchar below 256 */
3280     if (classnum == _CC_IDCONT) {
3281         classnum = _CC_WORDCHAR;
3282     }
3283     else if (classnum == _CC_IDFIRST) {
3284         if (*p == '_') {
3285             return TRUE;
3286         }
3287         classnum = _CC_ALPHA;
3288     }
3289 
3290     if (! use_locale) {
3291         if (! use_utf8 || UTF8_IS_INVARIANT(*p)) {
3292             return _generic_isCC(*p, classnum);
3293         }
3294 
3295         return _generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p + 1 )), classnum);
3296     }
3297     else {
3298         if (! use_utf8 || UTF8_IS_INVARIANT(*p)) {
3299             return isFOO_lc(classnum, *p);
3300         }
3301 
3302         return isFOO_lc(classnum, EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p + 1 )));
3303     }
3304 
3305     NOT_REACHED; /* NOTREACHED */
3306 }
3307 
3308 bool
Perl__is_utf8_FOO_with_len(pTHX_ const U8 classnum,const U8 * p,const U8 * const e)3309 Perl__is_utf8_FOO_with_len(pTHX_ const U8 classnum, const U8 *p,
3310                                                             const U8 * const e)
3311 {
3312     dVAR;
3313     PERL_ARGS_ASSERT__IS_UTF8_FOO_WITH_LEN;
3314 
3315     return is_utf8_common_with_len(p, e, PL_XPosix_ptrs[classnum]);
3316 }
3317 
3318 bool
Perl__is_utf8_perl_idstart_with_len(pTHX_ const U8 * p,const U8 * const e)3319 Perl__is_utf8_perl_idstart_with_len(pTHX_ const U8 *p, const U8 * const e)
3320 {
3321     dVAR;
3322     PERL_ARGS_ASSERT__IS_UTF8_PERL_IDSTART_WITH_LEN;
3323 
3324     return is_utf8_common_with_len(p, e, PL_utf8_perl_idstart);
3325 }
3326 
3327 bool
Perl__is_utf8_xidstart(pTHX_ const U8 * p)3328 Perl__is_utf8_xidstart(pTHX_ const U8 *p)
3329 {
3330     dVAR;
3331     PERL_ARGS_ASSERT__IS_UTF8_XIDSTART;
3332 
3333     if (*p == '_')
3334 	return TRUE;
3335     return is_utf8_common(p, PL_utf8_xidstart);
3336 }
3337 
3338 bool
Perl__is_utf8_perl_idcont_with_len(pTHX_ const U8 * p,const U8 * const e)3339 Perl__is_utf8_perl_idcont_with_len(pTHX_ const U8 *p, const U8 * const e)
3340 {
3341     dVAR;
3342     PERL_ARGS_ASSERT__IS_UTF8_PERL_IDCONT_WITH_LEN;
3343 
3344     return is_utf8_common_with_len(p, e, PL_utf8_perl_idcont);
3345 }
3346 
3347 bool
Perl__is_utf8_idcont(pTHX_ const U8 * p)3348 Perl__is_utf8_idcont(pTHX_ const U8 *p)
3349 {
3350     dVAR;
3351     PERL_ARGS_ASSERT__IS_UTF8_IDCONT;
3352 
3353     return is_utf8_common(p, PL_utf8_idcont);
3354 }
3355 
3356 bool
Perl__is_utf8_xidcont(pTHX_ const U8 * p)3357 Perl__is_utf8_xidcont(pTHX_ const U8 *p)
3358 {
3359     dVAR;
3360     PERL_ARGS_ASSERT__IS_UTF8_XIDCONT;
3361 
3362     return is_utf8_common(p, PL_utf8_xidcont);
3363 }
3364 
3365 bool
Perl__is_utf8_mark(pTHX_ const U8 * p)3366 Perl__is_utf8_mark(pTHX_ const U8 *p)
3367 {
3368     dVAR;
3369     PERL_ARGS_ASSERT__IS_UTF8_MARK;
3370 
3371     return is_utf8_common(p, PL_utf8_mark);
3372 }
3373 
3374 STATIC UV
S__to_utf8_case(pTHX_ const UV uv1,const U8 * p,U8 * ustrp,STRLEN * lenp,SV * invlist,const int * const invmap,const unsigned int * const * const aux_tables,const U8 * const aux_table_lengths,const char * const normal)3375 S__to_utf8_case(pTHX_ const UV uv1, const U8 *p,
3376                       U8* ustrp, STRLEN *lenp,
3377                       SV *invlist, const int * const invmap,
3378                       const unsigned int * const * const aux_tables,
3379                       const U8 * const aux_table_lengths,
3380                       const char * const normal)
3381 {
3382     STRLEN len = 0;
3383 
3384     /* Change the case of code point 'uv1' whose UTF-8 representation (assumed
3385      * by this routine to be valid) begins at 'p'.  'normal' is a string to use
3386      * to name the new case in any generated messages, as a fallback if the
3387      * operation being used is not available.  The new case is given by the
3388      * data structures in the remaining arguments.
3389      *
3390      * On return 'ustrp' points to '*lenp' UTF-8 encoded bytes representing the
3391      * entire changed case string, and the return value is the first code point
3392      * in that string */
3393 
3394     PERL_ARGS_ASSERT__TO_UTF8_CASE;
3395 
3396     /* For code points that don't change case, we already know that the output
3397      * of this function is the unchanged input, so we can skip doing look-ups
3398      * for them.  Unfortunately the case-changing code points are scattered
3399      * around.  But there are some long consecutive ranges where there are no
3400      * case changing code points.  By adding tests, we can eliminate the lookup
3401      * for all the ones in such ranges.  This is currently done here only for
3402      * just a few cases where the scripts are in common use in modern commerce
3403      * (and scripts adjacent to those which can be included without additional
3404      * tests). */
3405 
3406     if (uv1 >= 0x0590) {
3407         /* This keeps from needing further processing the code points most
3408          * likely to be used in the following non-cased scripts: Hebrew,
3409          * Arabic, Syriac, Thaana, NKo, Samaritan, Mandaic, Devanagari,
3410          * Bengali, Gurmukhi, Gujarati, Oriya, Tamil, Telugu, Kannada,
3411          * Malayalam, Sinhala, Thai, Lao, Tibetan, Myanmar */
3412         if (uv1 < 0x10A0) {
3413             goto cases_to_self;
3414         }
3415 
3416         /* The following largish code point ranges also don't have case
3417          * changes, but khw didn't think they warranted extra tests to speed
3418          * them up (which would slightly slow down everything else above them):
3419          * 1100..139F   Hangul Jamo, Ethiopic
3420          * 1400..1CFF   Unified Canadian Aboriginal Syllabics, Ogham, Runic,
3421          *              Tagalog, Hanunoo, Buhid, Tagbanwa, Khmer, Mongolian,
3422          *              Limbu, Tai Le, New Tai Lue, Buginese, Tai Tham,
3423          *              Combining Diacritical Marks Extended, Balinese,
3424          *              Sundanese, Batak, Lepcha, Ol Chiki
3425          * 2000..206F   General Punctuation
3426          */
3427 
3428         if (uv1 >= 0x2D30) {
3429 
3430             /* This keeps the from needing further processing the code points
3431              * most likely to be used in the following non-cased major scripts:
3432              * CJK, Katakana, Hiragana, plus some less-likely scripts.
3433              *
3434              * (0x2D30 above might have to be changed to 2F00 in the unlikely
3435              * event that Unicode eventually allocates the unused block as of
3436              * v8.0 2FE0..2FEF to code points that are cased.  khw has verified
3437              * that the test suite will start having failures to alert you
3438              * should that happen) */
3439             if (uv1 < 0xA640) {
3440                 goto cases_to_self;
3441             }
3442 
3443             if (uv1 >= 0xAC00) {
3444                 if (UNLIKELY(UNICODE_IS_SURROGATE(uv1))) {
3445                     if (ckWARN_d(WARN_SURROGATE)) {
3446                         const char* desc = (PL_op) ? OP_DESC(PL_op) : normal;
3447                         Perl_warner(aTHX_ packWARN(WARN_SURROGATE),
3448                             "Operation \"%s\" returns its argument for"
3449                             " UTF-16 surrogate U+%04" UVXf, desc, uv1);
3450                     }
3451                     goto cases_to_self;
3452                 }
3453 
3454                 /* AC00..FAFF Catches Hangul syllables and private use, plus
3455                  * some others */
3456                 if (uv1 < 0xFB00) {
3457                     goto cases_to_self;
3458                 }
3459 
3460                 if (UNLIKELY(UNICODE_IS_SUPER(uv1))) {
3461                     if (UNLIKELY(uv1 > MAX_LEGAL_CP)) {
3462                         Perl_croak(aTHX_ cp_above_legal_max, uv1,
3463                                          MAX_LEGAL_CP);
3464                     }
3465                     if (ckWARN_d(WARN_NON_UNICODE)) {
3466                         const char* desc = (PL_op) ? OP_DESC(PL_op) : normal;
3467                         Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
3468                             "Operation \"%s\" returns its argument for"
3469                             " non-Unicode code point 0x%04" UVXf, desc, uv1);
3470                     }
3471                     goto cases_to_self;
3472                 }
3473 #ifdef HIGHEST_CASE_CHANGING_CP_FOR_USE_ONLY_BY_UTF8_DOT_C
3474                 if (UNLIKELY(uv1
3475                     > HIGHEST_CASE_CHANGING_CP_FOR_USE_ONLY_BY_UTF8_DOT_C))
3476                 {
3477 
3478                     /* As of Unicode 10.0, this means we avoid swash creation
3479                      * for anything beyond high Plane 1 (below emojis)  */
3480                     goto cases_to_self;
3481                 }
3482 #endif
3483             }
3484         }
3485 
3486 	/* Note that non-characters are perfectly legal, so no warning should
3487          * be given. */
3488     }
3489 
3490     {
3491         unsigned int i;
3492         const unsigned int * cp_list;
3493         U8 * d;
3494 
3495         /* 'index' is guaranteed to be non-negative, as this is an inversion
3496          * map that covers all possible inputs.  See [perl #133365] */
3497         SSize_t index = _invlist_search(invlist, uv1);
3498         IV base = invmap[index];
3499 
3500         /* The data structures are set up so that if 'base' is non-negative,
3501          * the case change is 1-to-1; and if 0, the change is to itself */
3502         if (base >= 0) {
3503             IV lc;
3504 
3505             if (base == 0) {
3506                 goto cases_to_self;
3507             }
3508 
3509             /* This computes, e.g. lc(H) as 'H - A + a', using the lc table */
3510             lc = base + uv1 - invlist_array(invlist)[index];
3511             *lenp = uvchr_to_utf8(ustrp, lc) - ustrp;
3512             return lc;
3513         }
3514 
3515         /* Here 'base' is negative.  That means the mapping is 1-to-many, and
3516          * requires an auxiliary table look up.  abs(base) gives the index into
3517          * a list of such tables which points to the proper aux table.  And a
3518          * parallel list gives the length of each corresponding aux table. */
3519         cp_list = aux_tables[-base];
3520 
3521         /* Create the string of UTF-8 from the mapped-to code points */
3522         d = ustrp;
3523         for (i = 0; i < aux_table_lengths[-base]; i++) {
3524             d = uvchr_to_utf8(d, cp_list[i]);
3525         }
3526         *d = '\0';
3527         *lenp = d - ustrp;
3528 
3529         return cp_list[0];
3530     }
3531 
3532     /* Here, there was no mapping defined, which means that the code point maps
3533      * to itself.  Return the inputs */
3534   cases_to_self:
3535     if (p) {
3536         len = UTF8SKIP(p);
3537         if (p != ustrp) {   /* Don't copy onto itself */
3538             Copy(p, ustrp, len, U8);
3539         }
3540         *lenp = len;
3541     }
3542     else {
3543 	*lenp = uvchr_to_utf8(ustrp, uv1) - ustrp;
3544     }
3545 
3546     return uv1;
3547 
3548 }
3549 
3550 Size_t
Perl__inverse_folds(pTHX_ const UV cp,unsigned int * first_folds_to,const unsigned int ** remaining_folds_to)3551 Perl__inverse_folds(pTHX_ const UV cp, unsigned int * first_folds_to,
3552                           const unsigned int ** remaining_folds_to)
3553 {
3554     /* Returns the count of the number of code points that fold to the input
3555      * 'cp' (besides itself).
3556      *
3557      * If the return is 0, there is nothing else that folds to it, and
3558      * '*first_folds_to' is set to 0, and '*remaining_folds_to' is set to NULL.
3559      *
3560      * If the return is 1, '*first_folds_to' is set to the single code point,
3561      * and '*remaining_folds_to' is set to NULL.
3562      *
3563      * Otherwise, '*first_folds_to' is set to a code point, and
3564      * '*remaining_fold_to' is set to an array that contains the others.  The
3565      * length of this array is the returned count minus 1.
3566      *
3567      * The reason for this convolution is to avoid having to deal with
3568      * allocating and freeing memory.  The lists are already constructed, so
3569      * the return can point to them, but single code points aren't, so would
3570      * need to be constructed if we didn't employ something like this API */
3571 
3572     dVAR;
3573     /* 'index' is guaranteed to be non-negative, as this is an inversion map
3574      * that covers all possible inputs.  See [perl #133365] */
3575     SSize_t index = _invlist_search(PL_utf8_foldclosures, cp);
3576     int base = _Perl_IVCF_invmap[index];
3577 
3578     PERL_ARGS_ASSERT__INVERSE_FOLDS;
3579 
3580     if (base == 0) {            /* No fold */
3581         *first_folds_to = 0;
3582         *remaining_folds_to = NULL;
3583         return 0;
3584     }
3585 
3586 #ifndef HAS_IVCF_AUX_TABLES     /* This Unicode version only has 1-1 folds */
3587 
3588     assert(base > 0);
3589 
3590 #else
3591 
3592     if (UNLIKELY(base < 0)) {   /* Folds to more than one character */
3593 
3594         /* The data structure is set up so that the absolute value of 'base' is
3595          * an index into a table of pointers to arrays, with the array
3596          * corresponding to the index being the list of code points that fold
3597          * to 'cp', and the parallel array containing the length of the list
3598          * array */
3599         *first_folds_to = IVCF_AUX_TABLE_ptrs[-base][0];
3600         *remaining_folds_to = IVCF_AUX_TABLE_ptrs[-base] + 1; /* +1 excludes
3601                                                                  *first_folds_to
3602                                                                 */
3603         return IVCF_AUX_TABLE_lengths[-base];
3604     }
3605 
3606 #endif
3607 
3608     /* Only the single code point.  This works like 'fc(G) = G - A + a' */
3609     *first_folds_to = base + cp - invlist_array(PL_utf8_foldclosures)[index];
3610     *remaining_folds_to = NULL;
3611     return 1;
3612 }
3613 
3614 STATIC UV
S_check_locale_boundary_crossing(pTHX_ const U8 * const p,const UV result,U8 * const ustrp,STRLEN * lenp)3615 S_check_locale_boundary_crossing(pTHX_ const U8* const p, const UV result,
3616                                        U8* const ustrp, STRLEN *lenp)
3617 {
3618     /* This is called when changing the case of a UTF-8-encoded character above
3619      * the Latin1 range, and the operation is in a non-UTF-8 locale.  If the
3620      * result contains a character that crosses the 255/256 boundary, disallow
3621      * the change, and return the original code point.  See L<perlfunc/lc> for
3622      * why;
3623      *
3624      * p	points to the original string whose case was changed; assumed
3625      *          by this routine to be well-formed
3626      * result	the code point of the first character in the changed-case string
3627      * ustrp	points to the changed-case string (<result> represents its
3628      *          first char)
3629      * lenp	points to the length of <ustrp> */
3630 
3631     UV original;    /* To store the first code point of <p> */
3632 
3633     PERL_ARGS_ASSERT_CHECK_LOCALE_BOUNDARY_CROSSING;
3634 
3635     assert(UTF8_IS_ABOVE_LATIN1(*p));
3636 
3637     /* We know immediately if the first character in the string crosses the
3638      * boundary, so can skip testing */
3639     if (result > 255) {
3640 
3641 	/* Look at every character in the result; if any cross the
3642 	* boundary, the whole thing is disallowed */
3643 	U8* s = ustrp + UTF8SKIP(ustrp);
3644 	U8* e = ustrp + *lenp;
3645 	while (s < e) {
3646 	    if (! UTF8_IS_ABOVE_LATIN1(*s)) {
3647 		goto bad_crossing;
3648 	    }
3649 	    s += UTF8SKIP(s);
3650 	}
3651 
3652         /* Here, no characters crossed, result is ok as-is, but we warn. */
3653         _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(p, p + UTF8SKIP(p));
3654 	return result;
3655     }
3656 
3657   bad_crossing:
3658 
3659     /* Failed, have to return the original */
3660     original = valid_utf8_to_uvchr(p, lenp);
3661 
3662     /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
3663     Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
3664                            "Can't do %s(\"\\x{%" UVXf "}\") on non-UTF-8"
3665                            " locale; resolved to \"\\x{%" UVXf "}\".",
3666                            OP_DESC(PL_op),
3667                            original,
3668                            original);
3669     Copy(p, ustrp, *lenp, char);
3670     return original;
3671 }
3672 
3673 STATIC U32
S_check_and_deprecate(pTHX_ const U8 * p,const U8 ** e,const unsigned int type,const bool use_locale,const char * const file,const unsigned line)3674 S_check_and_deprecate(pTHX_ const U8 *p,
3675                             const U8 **e,
3676                             const unsigned int type,    /* See below */
3677                             const bool use_locale,      /* Is this a 'LC_'
3678                                                            macro call? */
3679                             const char * const file,
3680                             const unsigned line)
3681 {
3682     /* This is a temporary function to deprecate the unsafe calls to the case
3683      * changing macros and functions.  It keeps all the special stuff in just
3684      * one place.
3685      *
3686      * It updates *e with the pointer to the end of the input string.  If using
3687      * the old-style macros, *e is NULL on input, and so this function assumes
3688      * the input string is long enough to hold the entire UTF-8 sequence, and
3689      * sets *e accordingly, but it then returns a flag to pass the
3690      * utf8n_to_uvchr(), to tell it that this size is a guess, and to avoid
3691      * using the full length if possible.
3692      *
3693      * It also does the assert that *e > p when *e is not NULL.  This should be
3694      * migrated to the callers when this function gets deleted.
3695      *
3696      * The 'type' parameter is used for the caller to specify which case
3697      * changing function this is called from: */
3698 
3699 #       define DEPRECATE_TO_UPPER 0
3700 #       define DEPRECATE_TO_TITLE 1
3701 #       define DEPRECATE_TO_LOWER 2
3702 #       define DEPRECATE_TO_FOLD  3
3703 
3704     U32 utf8n_flags = 0;
3705     const char * name;
3706     const char * alternative;
3707 
3708     PERL_ARGS_ASSERT_CHECK_AND_DEPRECATE;
3709 
3710     if (*e == NULL) {
3711         utf8n_flags = _UTF8_NO_CONFIDENCE_IN_CURLEN;
3712 
3713         /* strnlen() makes this function safe for the common case of
3714          * NUL-terminated strings */
3715         *e = p + my_strnlen((char *) p, UTF8SKIP(p));
3716 
3717         /* For mathoms.c calls, we use the function name we know is stored
3718          * there.  It could be part of a larger path */
3719         if (type == DEPRECATE_TO_UPPER) {
3720             name = instr(file, "mathoms.c")
3721                    ? "to_utf8_upper"
3722                    : "toUPPER_utf8";
3723             alternative = "toUPPER_utf8_safe";
3724         }
3725         else if (type == DEPRECATE_TO_TITLE) {
3726             name = instr(file, "mathoms.c")
3727                    ? "to_utf8_title"
3728                    : "toTITLE_utf8";
3729             alternative = "toTITLE_utf8_safe";
3730         }
3731         else if (type == DEPRECATE_TO_LOWER) {
3732             name = instr(file, "mathoms.c")
3733                    ? "to_utf8_lower"
3734                    : "toLOWER_utf8";
3735             alternative = "toLOWER_utf8_safe";
3736         }
3737         else if (type == DEPRECATE_TO_FOLD) {
3738             name = instr(file, "mathoms.c")
3739                    ? "to_utf8_fold"
3740                    : "toFOLD_utf8";
3741             alternative = "toFOLD_utf8_safe";
3742         }
3743         else Perl_croak(aTHX_ "panic: Unexpected case change type");
3744 
3745         warn_on_first_deprecated_use(name, alternative, use_locale, file, line);
3746     }
3747     else {
3748         assert (p < *e);
3749     }
3750 
3751     return utf8n_flags;
3752 }
3753 
3754 STATIC UV
S_turkic_fc(pTHX_ const U8 * const p,const U8 * const e,U8 * ustrp,STRLEN * lenp)3755 S_turkic_fc(pTHX_ const U8 * const p, const U8 * const e,
3756                         U8 * ustrp, STRLEN *lenp)
3757 {
3758     /* Returns 0 if the foldcase of the input UTF-8 encoded sequence from
3759      * p0..e-1 according to Turkic rules is the same as for non-Turkic.
3760      * Otherwise, it returns the first code point of the Turkic foldcased
3761      * sequence, and the entire sequence will be stored in *ustrp.  ustrp will
3762      * contain *lenp bytes
3763      *
3764      * Turkic differs only from non-Turkic in that 'i' and LATIN CAPITAL LETTER
3765      * I WITH DOT ABOVE form a case pair, as do 'I' and LATIN SMALL LETTER
3766      * DOTLESS I */
3767 
3768     PERL_ARGS_ASSERT_TURKIC_FC;
3769     assert(e > p);
3770 
3771     if (UNLIKELY(*p == 'I')) {
3772         *lenp = 2;
3773         ustrp[0] = UTF8_TWO_BYTE_HI(LATIN_SMALL_LETTER_DOTLESS_I);
3774         ustrp[1] = UTF8_TWO_BYTE_LO(LATIN_SMALL_LETTER_DOTLESS_I);
3775         return LATIN_SMALL_LETTER_DOTLESS_I;
3776     }
3777 
3778     if (UNLIKELY(memBEGINs(p, e - p,
3779                            LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE_UTF8)))
3780     {
3781         *lenp = 1;
3782         *ustrp = 'i';
3783         return 'i';
3784     }
3785 
3786     return 0;
3787 }
3788 
3789 STATIC UV
S_turkic_lc(pTHX_ const U8 * const p0,const U8 * const e,U8 * ustrp,STRLEN * lenp)3790 S_turkic_lc(pTHX_ const U8 * const p0, const U8 * const e,
3791                         U8 * ustrp, STRLEN *lenp)
3792 {
3793     /* Returns 0 if the lowercase of the input UTF-8 encoded sequence from
3794      * p0..e-1 according to Turkic rules is the same as for non-Turkic.
3795      * Otherwise, it returns the first code point of the Turkic lowercased
3796      * sequence, and the entire sequence will be stored in *ustrp.  ustrp will
3797      * contain *lenp bytes */
3798 
3799     dVAR;
3800     PERL_ARGS_ASSERT_TURKIC_LC;
3801     assert(e > p0);
3802 
3803     /* A 'I' requires context as to what to do */
3804     if (UNLIKELY(*p0 == 'I')) {
3805         const U8 * p = p0 + 1;
3806 
3807         /* According to the Unicode SpecialCasing.txt file, a capital 'I'
3808          * modified by a dot above lowercases to 'i' even in turkic locales. */
3809         while (p < e) {
3810             UV cp;
3811 
3812             if (memBEGINs(p, e - p, COMBINING_DOT_ABOVE_UTF8)) {
3813                 ustrp[0] = 'i';
3814                 *lenp = 1;
3815                 return 'i';
3816             }
3817 
3818             /* For the dot above to modify the 'I', it must be part of a
3819              * combining sequence immediately following the 'I', and no other
3820              * modifier with a ccc of 230 may intervene */
3821             cp = utf8_to_uvchr_buf(p, e, NULL);
3822             if (! _invlist_contains_cp(PL_CCC_non0_non230, cp)) {
3823                 break;
3824             }
3825 
3826             /* Here the combining sequence continues */
3827             p += UTF8SKIP(p);
3828         }
3829     }
3830 
3831     /* In all other cases the lc is the same as the fold */
3832     return turkic_fc(p0, e, ustrp, lenp);
3833 }
3834 
3835 STATIC UV
S_turkic_uc(pTHX_ const U8 * const p,const U8 * const e,U8 * ustrp,STRLEN * lenp)3836 S_turkic_uc(pTHX_ const U8 * const p, const U8 * const e,
3837                         U8 * ustrp, STRLEN *lenp)
3838 {
3839     /* Returns 0 if the upper or title-case of the input UTF-8 encoded sequence
3840      * from p0..e-1 according to Turkic rules is the same as for non-Turkic.
3841      * Otherwise, it returns the first code point of the Turkic upper or
3842      * title-cased sequence, and the entire sequence will be stored in *ustrp.
3843      * ustrp will contain *lenp bytes
3844      *
3845      * Turkic differs only from non-Turkic in that 'i' and LATIN CAPITAL LETTER
3846      * I WITH DOT ABOVE form a case pair, as do 'I' and and LATIN SMALL LETTER
3847      * DOTLESS I */
3848 
3849     PERL_ARGS_ASSERT_TURKIC_UC;
3850     assert(e > p);
3851 
3852     if (*p == 'i') {
3853         *lenp = 2;
3854         ustrp[0] = UTF8_TWO_BYTE_HI(LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE);
3855         ustrp[1] = UTF8_TWO_BYTE_LO(LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE);
3856         return LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE;
3857     }
3858 
3859     if (memBEGINs(p, e - p, LATIN_SMALL_LETTER_DOTLESS_I_UTF8)) {
3860         *lenp = 1;
3861         *ustrp = 'I';
3862         return 'I';
3863     }
3864 
3865     return 0;
3866 }
3867 
3868 /* The process for changing the case is essentially the same for the four case
3869  * change types, except there are complications for folding.  Otherwise the
3870  * difference is only which case to change to.  To make sure that they all do
3871  * the same thing, the bodies of the functions are extracted out into the
3872  * following two macros.  The functions are written with the same variable
3873  * names, and these are known and used inside these macros.  It would be
3874  * better, of course, to have inline functions to do it, but since different
3875  * macros are called, depending on which case is being changed to, this is not
3876  * feasible in C (to khw's knowledge).  Two macros are created so that the fold
3877  * function can start with the common start macro, then finish with its special
3878  * handling; while the other three cases can just use the common end macro.
3879  *
3880  * The algorithm is to use the proper (passed in) macro or function to change
3881  * the case for code points that are below 256.  The macro is used if using
3882  * locale rules for the case change; the function if not.  If the code point is
3883  * above 255, it is computed from the input UTF-8, and another macro is called
3884  * to do the conversion.  If necessary, the output is converted to UTF-8.  If
3885  * using a locale, we have to check that the change did not cross the 255/256
3886  * boundary, see check_locale_boundary_crossing() for further details.
3887  *
3888  * The macros are split with the correct case change for the below-256 case
3889  * stored into 'result', and in the middle of an else clause for the above-255
3890  * case.  At that point in the 'else', 'result' is not the final result, but is
3891  * the input code point calculated from the UTF-8.  The fold code needs to
3892  * realize all this and take it from there.
3893  *
3894  * To deal with Turkic locales, the function specified by the parameter
3895  * 'turkic' is called when appropriate.
3896  *
3897  * If you read the two macros as sequential, it's easier to understand what's
3898  * going on. */
3899 #define CASE_CHANGE_BODY_START(locale_flags, LC_L1_change_macro, L1_func,    \
3900                                L1_func_extra_param, turkic)                  \
3901                                                                              \
3902     if (flags & (locale_flags)) {                                            \
3903         _CHECK_AND_WARN_PROBLEMATIC_LOCALE;                                  \
3904         if (IN_UTF8_CTYPE_LOCALE) {                                          \
3905             if (UNLIKELY(PL_in_utf8_turkic_locale)) {                        \
3906                 UV ret = turkic(p, e, ustrp, lenp);                          \
3907                 if (ret) return ret;                                         \
3908             }                                                                \
3909                                                                              \
3910             /* Otherwise, treat a UTF-8 locale as not being in locale at     \
3911              * all */                                                        \
3912             flags &= ~(locale_flags);                                        \
3913         }                                                                    \
3914     }                                                                        \
3915                                                                              \
3916     if (UTF8_IS_INVARIANT(*p)) {                                             \
3917         if (flags & (locale_flags)) {                                        \
3918             result = LC_L1_change_macro(*p);                                 \
3919         }                                                                    \
3920         else {                                                               \
3921             return L1_func(*p, ustrp, lenp, L1_func_extra_param);            \
3922         }                                                                    \
3923     }                                                                        \
3924     else if UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(p, e) {                          \
3925         U8 c = EIGHT_BIT_UTF8_TO_NATIVE(*p, *(p+1));                         \
3926         if (flags & (locale_flags)) {                                        \
3927             result = LC_L1_change_macro(c);                                  \
3928         }                                                                    \
3929         else {                                                               \
3930             return L1_func(c, ustrp, lenp,  L1_func_extra_param);            \
3931         }                                                                    \
3932     }                                                                        \
3933     else {  /* malformed UTF-8 or ord above 255 */                           \
3934         STRLEN len_result;                                                   \
3935         result = utf8n_to_uvchr(p, e - p, &len_result, UTF8_CHECK_ONLY);     \
3936         if (len_result == (STRLEN) -1) {                                     \
3937             _force_out_malformed_utf8_message(p, e, utf8n_flags,             \
3938                                                             1 /* Die */ );   \
3939         }
3940 
3941 #define CASE_CHANGE_BODY_END(locale_flags, change_macro)                     \
3942         result = change_macro(result, p, ustrp, lenp);                       \
3943                                                                              \
3944         if (flags & (locale_flags)) {                                        \
3945             result = check_locale_boundary_crossing(p, result, ustrp, lenp); \
3946         }                                                                    \
3947         return result;                                                       \
3948     }                                                                        \
3949                                                                              \
3950     /* Here, used locale rules.  Convert back to UTF-8 */                    \
3951     if (UTF8_IS_INVARIANT(result)) {                                         \
3952         *ustrp = (U8) result;                                                \
3953         *lenp = 1;                                                           \
3954     }                                                                        \
3955     else {                                                                   \
3956         *ustrp = UTF8_EIGHT_BIT_HI((U8) result);                             \
3957         *(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);                       \
3958         *lenp = 2;                                                           \
3959     }                                                                        \
3960                                                                              \
3961     return result;
3962 
3963 /*
3964 =for apidoc to_utf8_upper
3965 
3966 Instead use L</toUPPER_utf8_safe>.
3967 
3968 =cut */
3969 
3970 /* Not currently externally documented, and subject to change:
3971  * <flags> is set iff iff the rules from the current underlying locale are to
3972  *         be used. */
3973 
3974 UV
Perl__to_utf8_upper_flags(pTHX_ const U8 * p,const U8 * e,U8 * ustrp,STRLEN * lenp,bool flags,const char * const file,const int line)3975 Perl__to_utf8_upper_flags(pTHX_ const U8 *p,
3976                                 const U8 *e,
3977                                 U8* ustrp,
3978                                 STRLEN *lenp,
3979                                 bool flags,
3980                                 const char * const file,
3981                                 const int line)
3982 {
3983     dVAR;
3984     UV result;
3985     const U32 utf8n_flags = check_and_deprecate(p, &e, DEPRECATE_TO_UPPER,
3986                                                 cBOOL(flags), file, line);
3987 
3988     PERL_ARGS_ASSERT__TO_UTF8_UPPER_FLAGS;
3989 
3990     /* ~0 makes anything non-zero in 'flags' mean we are using locale rules */
3991     /* 2nd char of uc(U+DF) is 'S' */
3992     CASE_CHANGE_BODY_START(~0, toUPPER_LC, _to_upper_title_latin1, 'S',
3993                                                                     turkic_uc);
3994     CASE_CHANGE_BODY_END  (~0, CALL_UPPER_CASE);
3995 }
3996 
3997 /*
3998 =for apidoc to_utf8_title
3999 
4000 Instead use L</toTITLE_utf8_safe>.
4001 
4002 =cut */
4003 
4004 /* Not currently externally documented, and subject to change:
4005  * <flags> is set iff the rules from the current underlying locale are to be
4006  *         used.  Since titlecase is not defined in POSIX, for other than a
4007  *         UTF-8 locale, uppercase is used instead for code points < 256.
4008  */
4009 
4010 UV
Perl__to_utf8_title_flags(pTHX_ const U8 * p,const U8 * e,U8 * ustrp,STRLEN * lenp,bool flags,const char * const file,const int line)4011 Perl__to_utf8_title_flags(pTHX_ const U8 *p,
4012                                 const U8 *e,
4013                                 U8* ustrp,
4014                                 STRLEN *lenp,
4015                                 bool flags,
4016                                 const char * const file,
4017                                 const int line)
4018 {
4019     dVAR;
4020     UV result;
4021     const U32 utf8n_flags = check_and_deprecate(p, &e, DEPRECATE_TO_TITLE,
4022                                                 cBOOL(flags), file, line);
4023 
4024     PERL_ARGS_ASSERT__TO_UTF8_TITLE_FLAGS;
4025 
4026     /* 2nd char of ucfirst(U+DF) is 's' */
4027     CASE_CHANGE_BODY_START(~0, toUPPER_LC, _to_upper_title_latin1, 's',
4028                                                                     turkic_uc);
4029     CASE_CHANGE_BODY_END  (~0, CALL_TITLE_CASE);
4030 }
4031 
4032 /*
4033 =for apidoc to_utf8_lower
4034 
4035 Instead use L</toLOWER_utf8_safe>.
4036 
4037 =cut */
4038 
4039 /* Not currently externally documented, and subject to change:
4040  * <flags> is set iff iff the rules from the current underlying locale are to
4041  *         be used.
4042  */
4043 
4044 UV
Perl__to_utf8_lower_flags(pTHX_ const U8 * p,const U8 * e,U8 * ustrp,STRLEN * lenp,bool flags,const char * const file,const int line)4045 Perl__to_utf8_lower_flags(pTHX_ const U8 *p,
4046                                 const U8 *e,
4047                                 U8* ustrp,
4048                                 STRLEN *lenp,
4049                                 bool flags,
4050                                 const char * const file,
4051                                 const int line)
4052 {
4053     dVAR;
4054     UV result;
4055     const U32 utf8n_flags = check_and_deprecate(p, &e, DEPRECATE_TO_LOWER,
4056                                                 cBOOL(flags), file, line);
4057 
4058     PERL_ARGS_ASSERT__TO_UTF8_LOWER_FLAGS;
4059 
4060     CASE_CHANGE_BODY_START(~0, toLOWER_LC, to_lower_latin1, 0 /* 0 is dummy */,
4061                                                                     turkic_lc);
4062     CASE_CHANGE_BODY_END  (~0, CALL_LOWER_CASE)
4063 }
4064 
4065 /*
4066 =for apidoc to_utf8_fold
4067 
4068 Instead use L</toFOLD_utf8_safe>.
4069 
4070 =cut */
4071 
4072 /* Not currently externally documented, and subject to change,
4073  * in <flags>
4074  *	bit FOLD_FLAGS_LOCALE is set iff the rules from the current underlying
4075  *	                      locale are to be used.
4076  *      bit FOLD_FLAGS_FULL   is set iff full case folds are to be used;
4077  *			      otherwise simple folds
4078  *      bit FOLD_FLAGS_NOMIX_ASCII is set iff folds of non-ASCII to ASCII are
4079  *			      prohibited
4080  */
4081 
4082 UV
Perl__to_utf8_fold_flags(pTHX_ const U8 * p,const U8 * e,U8 * ustrp,STRLEN * lenp,U8 flags,const char * const file,const int line)4083 Perl__to_utf8_fold_flags(pTHX_ const U8 *p,
4084                                const U8 *e,
4085                                U8* ustrp,
4086                                STRLEN *lenp,
4087                                U8 flags,
4088                                const char * const file,
4089                                const int line)
4090 {
4091     dVAR;
4092     UV result;
4093     const U32 utf8n_flags = check_and_deprecate(p, &e, DEPRECATE_TO_FOLD,
4094                                                 cBOOL(flags), file, line);
4095 
4096     PERL_ARGS_ASSERT__TO_UTF8_FOLD_FLAGS;
4097 
4098     /* These are mutually exclusive */
4099     assert (! ((flags & FOLD_FLAGS_LOCALE) && (flags & FOLD_FLAGS_NOMIX_ASCII)));
4100 
4101     assert(p != ustrp); /* Otherwise overwrites */
4102 
4103     CASE_CHANGE_BODY_START(FOLD_FLAGS_LOCALE, toFOLD_LC, _to_fold_latin1,
4104                  ((flags) & (FOLD_FLAGS_FULL | FOLD_FLAGS_NOMIX_ASCII)),
4105                                                                     turkic_fc);
4106 
4107 	result = CALL_FOLD_CASE(result, p, ustrp, lenp, flags & FOLD_FLAGS_FULL);
4108 
4109 	if (flags & FOLD_FLAGS_LOCALE) {
4110 
4111 #           define LONG_S_T      LATIN_SMALL_LIGATURE_LONG_S_T_UTF8
4112 #         ifdef LATIN_CAPITAL_LETTER_SHARP_S_UTF8
4113 #           define CAP_SHARP_S   LATIN_CAPITAL_LETTER_SHARP_S_UTF8
4114 
4115             /* Special case these two characters, as what normally gets
4116              * returned under locale doesn't work */
4117             if (memBEGINs((char *) p, e - p, CAP_SHARP_S))
4118             {
4119                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
4120                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
4121                               "Can't do fc(\"\\x{1E9E}\") on non-UTF-8 locale; "
4122                               "resolved to \"\\x{17F}\\x{17F}\".");
4123                 goto return_long_s;
4124             }
4125             else
4126 #endif
4127                  if (memBEGINs((char *) p, e - p, LONG_S_T))
4128             {
4129                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
4130                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
4131                               "Can't do fc(\"\\x{FB05}\") on non-UTF-8 locale; "
4132                               "resolved to \"\\x{FB06}\".");
4133                 goto return_ligature_st;
4134             }
4135 
4136 #if    UNICODE_MAJOR_VERSION   == 3         \
4137     && UNICODE_DOT_VERSION     == 0         \
4138     && UNICODE_DOT_DOT_VERSION == 1
4139 #           define DOTTED_I   LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE_UTF8
4140 
4141             /* And special case this on this Unicode version only, for the same
4142              * reaons the other two are special cased.  They would cross the
4143              * 255/256 boundary which is forbidden under /l, and so the code
4144              * wouldn't catch that they are equivalent (which they are only in
4145              * this release) */
4146             else if (memBEGINs((char *) p, e - p, DOTTED_I)) {
4147                 /* diag_listed_as: Can't do %s("%s") on non-UTF-8 locale; resolved to "%s". */
4148                 Perl_ck_warner(aTHX_ packWARN(WARN_LOCALE),
4149                               "Can't do fc(\"\\x{0130}\") on non-UTF-8 locale; "
4150                               "resolved to \"\\x{0131}\".");
4151                 goto return_dotless_i;
4152             }
4153 #endif
4154 
4155 	    return check_locale_boundary_crossing(p, result, ustrp, lenp);
4156 	}
4157 	else if (! (flags & FOLD_FLAGS_NOMIX_ASCII)) {
4158 	    return result;
4159 	}
4160 	else {
4161 	    /* This is called when changing the case of a UTF-8-encoded
4162              * character above the ASCII range, and the result should not
4163              * contain an ASCII character. */
4164 
4165 	    UV original;    /* To store the first code point of <p> */
4166 
4167 	    /* Look at every character in the result; if any cross the
4168 	    * boundary, the whole thing is disallowed */
4169 	    U8* s = ustrp;
4170 	    U8* e = ustrp + *lenp;
4171 	    while (s < e) {
4172 		if (isASCII(*s)) {
4173 		    /* Crossed, have to return the original */
4174 		    original = valid_utf8_to_uvchr(p, lenp);
4175 
4176                     /* But in these instances, there is an alternative we can
4177                      * return that is valid */
4178                     if (original == LATIN_SMALL_LETTER_SHARP_S
4179 #ifdef LATIN_CAPITAL_LETTER_SHARP_S /* not defined in early Unicode releases */
4180                         || original == LATIN_CAPITAL_LETTER_SHARP_S
4181 #endif
4182                     ) {
4183                         goto return_long_s;
4184                     }
4185                     else if (original == LATIN_SMALL_LIGATURE_LONG_S_T) {
4186                         goto return_ligature_st;
4187                     }
4188 #if    UNICODE_MAJOR_VERSION   == 3         \
4189     && UNICODE_DOT_VERSION     == 0         \
4190     && UNICODE_DOT_DOT_VERSION == 1
4191 
4192                     else if (original == LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE) {
4193                         goto return_dotless_i;
4194                     }
4195 #endif
4196 		    Copy(p, ustrp, *lenp, char);
4197 		    return original;
4198 		}
4199 		s += UTF8SKIP(s);
4200 	    }
4201 
4202 	    /* Here, no characters crossed, result is ok as-is */
4203 	    return result;
4204 	}
4205     }
4206 
4207     /* Here, used locale rules.  Convert back to UTF-8 */
4208     if (UTF8_IS_INVARIANT(result)) {
4209 	*ustrp = (U8) result;
4210 	*lenp = 1;
4211     }
4212     else {
4213 	*ustrp = UTF8_EIGHT_BIT_HI((U8) result);
4214 	*(ustrp + 1) = UTF8_EIGHT_BIT_LO((U8) result);
4215 	*lenp = 2;
4216     }
4217 
4218     return result;
4219 
4220   return_long_s:
4221     /* Certain folds to 'ss' are prohibited by the options, but they do allow
4222      * folds to a string of two of these characters.  By returning this
4223      * instead, then, e.g.,
4224      *      fc("\x{1E9E}") eq fc("\x{17F}\x{17F}")
4225      * works. */
4226 
4227     *lenp = 2 * sizeof(LATIN_SMALL_LETTER_LONG_S_UTF8) - 2;
4228     Copy(LATIN_SMALL_LETTER_LONG_S_UTF8   LATIN_SMALL_LETTER_LONG_S_UTF8,
4229         ustrp, *lenp, U8);
4230     return LATIN_SMALL_LETTER_LONG_S;
4231 
4232   return_ligature_st:
4233     /* Two folds to 'st' are prohibited by the options; instead we pick one and
4234      * have the other one fold to it */
4235 
4236     *lenp = sizeof(LATIN_SMALL_LIGATURE_ST_UTF8) - 1;
4237     Copy(LATIN_SMALL_LIGATURE_ST_UTF8, ustrp, *lenp, U8);
4238     return LATIN_SMALL_LIGATURE_ST;
4239 
4240 #if    UNICODE_MAJOR_VERSION   == 3         \
4241     && UNICODE_DOT_VERSION     == 0         \
4242     && UNICODE_DOT_DOT_VERSION == 1
4243 
4244   return_dotless_i:
4245     *lenp = sizeof(LATIN_SMALL_LETTER_DOTLESS_I_UTF8) - 1;
4246     Copy(LATIN_SMALL_LETTER_DOTLESS_I_UTF8, ustrp, *lenp, U8);
4247     return LATIN_SMALL_LETTER_DOTLESS_I;
4248 
4249 #endif
4250 
4251 }
4252 
4253 /* Note:
4254  * Returns a "swash" which is a hash described in utf8.c:Perl_swash_fetch().
4255  * C<pkg> is a pointer to a package name for SWASHNEW, should be "utf8".
4256  * For other parameters, see utf8::SWASHNEW in lib/utf8_heavy.pl.
4257  */
4258 
4259 SV*
4260 Perl_swash_init(pTHX_ const char* pkg, const char* name, SV *listsv,
4261                       I32 minbits, I32 none)
4262 {
4263     /* Returns a copy of a swash initiated by the called function.  This is the
4264      * public interface, and returning a copy prevents others from doing
4265      * mischief on the original.  The only remaining use of this is in tr/// */
4266 
4267     /*NOTE NOTE NOTE - If you want to use "return" in this routine you MUST
4268      * use the following define */
4269 
4270 #define SWASH_INIT_RETURN(x)   \
4271     PL_curpm= old_PL_curpm;         \
4272     return newSVsv(x)
4273 
4274     /* Initialize and return a swash, creating it if necessary.  It does this
4275      * by calling utf8_heavy.pl in the general case.
4276      *
4277      * pkg  is the name of the package that <name> should be in.
4278      * name is the name of the swash to find.
4279      * listsv is a string to initialize the swash with.  It must be of the form
4280      *	    documented as the subroutine return value in
4281      *	    L<perlunicode/User-Defined Character Properties>
4282      * minbits is the number of bits required to represent each data element.
4283      * none I (khw) do not understand this one, but it is used only in tr///.
4284      *
4285      * Thus there are two possible inputs to find the swash: <name> and
4286      * <listsv>.  At least one must be specified.  The result
4287      * will be the union of the specified ones, although <listsv>'s various
4288      * actions can intersect, etc. what <name> gives.  To avoid going out to
4289      * disk at all, <invlist> should specify completely what the swash should
4290      * have, and <listsv> should be &PL_sv_undef and <name> should be "".
4291      */
4292 
4293     PMOP *old_PL_curpm= PL_curpm; /* save away the old PL_curpm */
4294 
4295     SV* retval = &PL_sv_undef;
4296 
4297     PERL_ARGS_ASSERT_SWASH_INIT;
4298 
4299     assert(listsv != &PL_sv_undef || strNE(name, ""));
4300 
4301     PL_curpm= NULL; /* reset PL_curpm so that we dont get confused between the
4302                        regex that triggered the swash init and the swash init
4303                        perl logic itself.  See perl #122747 */
4304 
4305     /* If data was passed in to go out to utf8_heavy to find the swash of, do
4306      * so */
4307     if (listsv != &PL_sv_undef || strNE(name, "")) {
4308 	dSP;
4309 	const size_t pkg_len = strlen(pkg);
4310 	const size_t name_len = strlen(name);
4311 	HV * const stash = gv_stashpvn(pkg, pkg_len, 0);
4312 	SV* errsv_save;
4313 	GV *method;
4314 
4315 
4316 	PUSHSTACKi(PERLSI_MAGIC);
4317 	ENTER;
4318 	SAVEHINTS();
4319 	save_re_context();
4320 	/* We might get here via a subroutine signature which uses a utf8
4321 	 * parameter name, at which point PL_subname will have been set
4322 	 * but not yet used. */
4323 	save_item(PL_subname);
4324 	if (PL_parser && PL_parser->error_count)
4325 	    SAVEI8(PL_parser->error_count), PL_parser->error_count = 0;
4326 	method = gv_fetchmeth(stash, "SWASHNEW", 8, -1);
4327 	if (!method) {	/* demand load UTF-8 */
4328 	    ENTER;
4329 	    if ((errsv_save = GvSV(PL_errgv))) SAVEFREESV(errsv_save);
4330 	    GvSV(PL_errgv) = NULL;
4331 #ifndef NO_TAINT_SUPPORT
4332 	    /* It is assumed that callers of this routine are not passing in
4333 	     * any user derived data.  */
4334 	    /* Need to do this after save_re_context() as it will set
4335 	     * PL_tainted to 1 while saving $1 etc (see the code after getrx:
4336 	     * in Perl_magic_get).  Even line to create errsv_save can turn on
4337 	     * PL_tainted.  */
4338 	    SAVEBOOL(TAINT_get);
4339 	    TAINT_NOT;
4340 #endif
4341             require_pv("utf8_heavy.pl");
4342 	    {
4343 		/* Not ERRSV, as there is no need to vivify a scalar we are
4344 		   about to discard. */
4345 		SV * const errsv = GvSV(PL_errgv);
4346 		if (!SvTRUE(errsv)) {
4347 		    GvSV(PL_errgv) = SvREFCNT_inc_simple(errsv_save);
4348 		    SvREFCNT_dec(errsv);
4349 		}
4350 	    }
4351 	    LEAVE;
4352 	}
4353 	SPAGAIN;
4354 	PUSHMARK(SP);
4355 	EXTEND(SP,5);
4356 	mPUSHp(pkg, pkg_len);
4357 	mPUSHp(name, name_len);
4358 	PUSHs(listsv);
4359 	mPUSHi(minbits);
4360 	mPUSHi(none);
4361 	PUTBACK;
4362 	if ((errsv_save = GvSV(PL_errgv))) SAVEFREESV(errsv_save);
4363 	GvSV(PL_errgv) = NULL;
4364 	/* If we already have a pointer to the method, no need to use
4365 	 * call_method() to repeat the lookup.  */
4366 	if (method
4367             ? call_sv(MUTABLE_SV(method), G_SCALAR)
4368 	    : call_sv(newSVpvs_flags("SWASHNEW", SVs_TEMP), G_SCALAR | G_METHOD))
4369 	{
4370 	    retval = *PL_stack_sp--;
4371 	    SvREFCNT_inc(retval);
4372 	}
4373 	{
4374 	    /* Not ERRSV.  See above. */
4375 	    SV * const errsv = GvSV(PL_errgv);
4376 	    if (!SvTRUE(errsv)) {
4377 		GvSV(PL_errgv) = SvREFCNT_inc_simple(errsv_save);
4378 		SvREFCNT_dec(errsv);
4379 	    }
4380 	}
4381 	LEAVE;
4382 	POPSTACK;
4383 	if (IN_PERL_COMPILETIME) {
4384 	    CopHINTS_set(PL_curcop, PL_hints);
4385 	}
4386     } /* End of calling the module to find the swash */
4387 
4388     SWASH_INIT_RETURN(retval);
4389 #undef SWASH_INIT_RETURN
4390 }
4391 
4392 
4393 /* This API is wrong for special case conversions since we may need to
4394  * return several Unicode characters for a single Unicode character
4395  * (see lib/unicore/SpecCase.txt) The SWASHGET in lib/utf8_heavy.pl is
4396  * the lower-level routine, and it is similarly broken for returning
4397  * multiple values.  --jhi
4398  * For those, you should use S__to_utf8_case() instead */
4399 /* Now SWASHGET is recasted into S_swatch_get in this file. */
4400 
4401 /* Note:
4402  * Returns the value of property/mapping C<swash> for the first character
4403  * of the string C<ptr>. If C<do_utf8> is true, the string C<ptr> is
4404  * assumed to be in well-formed UTF-8. If C<do_utf8> is false, the string C<ptr>
4405  * is assumed to be in native 8-bit encoding. Caches the swatch in C<swash>.
4406  *
4407  * A "swash" is a hash which contains initially the keys/values set up by
4408  * SWASHNEW.  The purpose is to be able to completely represent a Unicode
4409  * property for all possible code points.  Things are stored in a compact form
4410  * (see utf8_heavy.pl) so that calculation is required to find the actual
4411  * property value for a given code point.  As code points are looked up, new
4412  * key/value pairs are added to the hash, so that the calculation doesn't have
4413  * to ever be re-done.  Further, each calculation is done, not just for the
4414  * desired one, but for a whole block of code points adjacent to that one.
4415  * For binary properties on ASCII machines, the block is usually for 64 code
4416  * points, starting with a code point evenly divisible by 64.  Thus if the
4417  * property value for code point 257 is requested, the code goes out and
4418  * calculates the property values for all 64 code points between 256 and 319,
4419  * and stores these as a single 64-bit long bit vector, called a "swatch",
4420  * under the key for code point 256.  The key is the UTF-8 encoding for code
4421  * point 256, minus the final byte.  Thus, if the length of the UTF-8 encoding
4422  * for a code point is 13 bytes, the key will be 12 bytes long.  If the value
4423  * for code point 258 is then requested, this code realizes that it would be
4424  * stored under the key for 256, and would find that value and extract the
4425  * relevant bit, offset from 256.
4426  *
4427  * Non-binary properties are stored in as many bits as necessary to represent
4428  * their values (32 currently, though the code is more general than that), not
4429  * as single bits, but the principle is the same: the value for each key is a
4430  * vector that encompasses the property values for all code points whose UTF-8
4431  * representations are represented by the key.  That is, for all code points
4432  * whose UTF-8 representations are length N bytes, and the key is the first N-1
4433  * bytes of that.
4434  */
4435 UV
4436 Perl_swash_fetch(pTHX_ SV *swash, const U8 *ptr, bool do_utf8)
4437 {
4438     HV *const hv = MUTABLE_HV(SvRV(swash));
4439     U32 klen;
4440     U32 off;
4441     STRLEN slen = 0;
4442     STRLEN needents;
4443     const U8 *tmps = NULL;
4444     SV *swatch;
4445     const U8 c = *ptr;
4446 
4447     PERL_ARGS_ASSERT_SWASH_FETCH;
4448 
4449     /* If it really isn't a hash, it isn't really swash; must be an inversion
4450      * list */
4451     if (SvTYPE(hv) != SVt_PVHV) {
4452         return _invlist_contains_cp((SV*)hv,
4453                                     (do_utf8)
4454                                      ? valid_utf8_to_uvchr(ptr, NULL)
4455                                      : c);
4456     }
4457 
4458     /* We store the values in a "swatch" which is a vec() value in a swash
4459      * hash.  Code points 0-255 are a single vec() stored with key length
4460      * (klen) 0.  All other code points have a UTF-8 representation
4461      * 0xAA..0xYY,0xZZ.  A vec() is constructed containing all of them which
4462      * share 0xAA..0xYY, which is the key in the hash to that vec.  So the key
4463      * length for them is the length of the encoded char - 1.  ptr[klen] is the
4464      * final byte in the sequence representing the character */
4465     if (!do_utf8 || UTF8_IS_INVARIANT(c)) {
4466         klen = 0;
4467 	needents = 256;
4468         off = c;
4469     }
4470     else if (UTF8_IS_DOWNGRADEABLE_START(c)) {
4471         klen = 0;
4472 	needents = 256;
4473         off = EIGHT_BIT_UTF8_TO_NATIVE(c, *(ptr + 1));
4474     }
4475     else {
4476         klen = UTF8SKIP(ptr) - 1;
4477 
4478         /* Each vec() stores 2**UTF_ACCUMULATION_SHIFT values.  The offset into
4479          * the vec is the final byte in the sequence.  (In EBCDIC this is
4480          * converted to I8 to get consecutive values.)  To help you visualize
4481          * all this:
4482          *                       Straight 1047   After final byte
4483          *             UTF-8      UTF-EBCDIC     I8 transform
4484          *  U+0400:  \xD0\x80    \xB8\x41\x41    \xB8\x41\xA0
4485          *  U+0401:  \xD0\x81    \xB8\x41\x42    \xB8\x41\xA1
4486          *    ...
4487          *  U+0409:  \xD0\x89    \xB8\x41\x4A    \xB8\x41\xA9
4488          *  U+040A:  \xD0\x8A    \xB8\x41\x51    \xB8\x41\xAA
4489          *    ...
4490          *  U+0412:  \xD0\x92    \xB8\x41\x59    \xB8\x41\xB2
4491          *  U+0413:  \xD0\x93    \xB8\x41\x62    \xB8\x41\xB3
4492          *    ...
4493          *  U+041B:  \xD0\x9B    \xB8\x41\x6A    \xB8\x41\xBB
4494          *  U+041C:  \xD0\x9C    \xB8\x41\x70    \xB8\x41\xBC
4495          *    ...
4496          *  U+041F:  \xD0\x9F    \xB8\x41\x73    \xB8\x41\xBF
4497          *  U+0420:  \xD0\xA0    \xB8\x42\x41    \xB8\x42\x41
4498          *
4499          * (There are no discontinuities in the elided (...) entries.)
4500          * The UTF-8 key for these 33 code points is '\xD0' (which also is the
4501          * key for the next 31, up through U+043F, whose UTF-8 final byte is
4502          * \xBF).  Thus in UTF-8, each key is for a vec() for 64 code points.
4503          * The final UTF-8 byte, which ranges between \x80 and \xBF, is an
4504          * index into the vec() swatch (after subtracting 0x80, which we
4505          * actually do with an '&').
4506          * In UTF-EBCDIC, each key is for a 32 code point vec().  The first 32
4507          * code points above have key '\xB8\x41'. The final UTF-EBCDIC byte has
4508          * dicontinuities which go away by transforming it into I8, and we
4509          * effectively subtract 0xA0 to get the index. */
4510 	needents = (1 << UTF_ACCUMULATION_SHIFT);
4511 	off      = NATIVE_UTF8_TO_I8(ptr[klen]) & UTF_CONTINUATION_MASK;
4512     }
4513 
4514     /*
4515      * This single-entry cache saves about 1/3 of the UTF-8 overhead in test
4516      * suite.  (That is, only 7-8% overall over just a hash cache.  Still,
4517      * it's nothing to sniff at.)  Pity we usually come through at least
4518      * two function calls to get here...
4519      *
4520      * NB: this code assumes that swatches are never modified, once generated!
4521      */
4522 
4523     if (hv   == PL_last_swash_hv &&
4524 	klen == PL_last_swash_klen &&
4525 	(!klen || memEQ((char *)ptr, (char *)PL_last_swash_key, klen)) )
4526     {
4527 	tmps = PL_last_swash_tmps;
4528 	slen = PL_last_swash_slen;
4529     }
4530     else {
4531 	/* Try our second-level swatch cache, kept in a hash. */
4532 	SV** svp = hv_fetch(hv, (const char*)ptr, klen, FALSE);
4533 
4534 	/* If not cached, generate it via swatch_get */
4535 	if (!svp || !SvPOK(*svp)
4536 		 || !(tmps = (const U8*)SvPV_const(*svp, slen)))
4537         {
4538             if (klen) {
4539                 const UV code_point = valid_utf8_to_uvchr(ptr, NULL);
4540                 swatch = swatch_get(swash,
4541                                     code_point & ~((UV)needents - 1),
4542 				    needents);
4543             }
4544             else {  /* For the first 256 code points, the swatch has a key of
4545                        length 0 */
4546                 swatch = swatch_get(swash, 0, needents);
4547             }
4548 
4549 	    if (IN_PERL_COMPILETIME)
4550 		CopHINTS_set(PL_curcop, PL_hints);
4551 
4552 	    svp = hv_store(hv, (const char *)ptr, klen, swatch, 0);
4553 
4554 	    if (!svp || !(tmps = (U8*)SvPV(*svp, slen))
4555 		     || (slen << 3) < needents)
4556 		Perl_croak(aTHX_ "panic: swash_fetch got improper swatch, "
4557 			   "svp=%p, tmps=%p, slen=%" UVuf ", needents=%" UVuf,
4558 			   svp, tmps, (UV)slen, (UV)needents);
4559 	}
4560 
4561 	PL_last_swash_hv = hv;
4562 	assert(klen <= sizeof(PL_last_swash_key));
4563 	PL_last_swash_klen = (U8)klen;
4564 	/* FIXME change interpvar.h?  */
4565 	PL_last_swash_tmps = (U8 *) tmps;
4566 	PL_last_swash_slen = slen;
4567 	if (klen)
4568 	    Copy(ptr, PL_last_swash_key, klen, U8);
4569     }
4570 
4571     switch ((int)((slen << 3) / needents)) {
4572     case 1:
4573 	return ((UV) tmps[off >> 3] & (1 << (off & 7))) != 0;
4574     case 8:
4575 	return ((UV) tmps[off]);
4576     case 16:
4577 	off <<= 1;
4578 	return
4579             ((UV) tmps[off    ] << 8) +
4580             ((UV) tmps[off + 1]);
4581     case 32:
4582 	off <<= 2;
4583 	return
4584             ((UV) tmps[off    ] << 24) +
4585             ((UV) tmps[off + 1] << 16) +
4586             ((UV) tmps[off + 2] <<  8) +
4587             ((UV) tmps[off + 3]);
4588     }
4589     Perl_croak(aTHX_ "panic: swash_fetch got swatch of unexpected bit width, "
4590 	       "slen=%" UVuf ", needents=%" UVuf, (UV)slen, (UV)needents);
4591     NORETURN_FUNCTION_END;
4592 }
4593 
4594 /* Read a single line of the main body of the swash input text.  These are of
4595  * the form:
4596  * 0053	0056	0073
4597  * where each number is hex.  The first two numbers form the minimum and
4598  * maximum of a range, and the third is the value associated with the range.
4599  * Not all swashes should have a third number
4600  *
4601  * On input: l	  points to the beginning of the line to be examined; it points
4602  *		  to somewhere in the string of the whole input text, and is
4603  *		  terminated by a \n or the null string terminator.
4604  *	     lend   points to the null terminator of that string
4605  *	     wants_value    is non-zero if the swash expects a third number
4606  *	     typestr is the name of the swash's mapping, like 'ToLower'
4607  * On output: *min, *max, and *val are set to the values read from the line.
4608  *	      returns a pointer just beyond the line examined.  If there was no
4609  *	      valid min number on the line, returns lend+1
4610  */
4611 
4612 STATIC U8*
4613 S_swash_scan_list_line(pTHX_ U8* l, U8* const lend, UV* min, UV* max, UV* val,
4614 			     const bool wants_value, const U8* const typestr)
4615 {
4616     const int  typeto  = typestr[0] == 'T' && typestr[1] == 'o';
4617     STRLEN numlen;	    /* Length of the number */
4618     I32 flags = PERL_SCAN_SILENT_ILLDIGIT
4619 		| PERL_SCAN_DISALLOW_PREFIX
4620 		| PERL_SCAN_SILENT_NON_PORTABLE;
4621 
4622     /* nl points to the next \n in the scan */
4623     U8* const nl = (U8*)memchr(l, '\n', lend - l);
4624 
4625     PERL_ARGS_ASSERT_SWASH_SCAN_LIST_LINE;
4626 
4627     /* Get the first number on the line: the range minimum */
4628     numlen = lend - l;
4629     *min = grok_hex((char *)l, &numlen, &flags, NULL);
4630     *max = *min;    /* So can never return without setting max */
4631     if (numlen)	    /* If found a hex number, position past it */
4632 	l += numlen;
4633     else if (nl) {	    /* Else, go handle next line, if any */
4634 	return nl + 1;	/* 1 is length of "\n" */
4635     }
4636     else {		/* Else, no next line */
4637 	return lend + 1;	/* to LIST's end at which \n is not found */
4638     }
4639 
4640     /* The max range value follows, separated by a BLANK */
4641     if (isBLANK(*l)) {
4642 	++l;
4643 	flags = PERL_SCAN_SILENT_ILLDIGIT
4644 		| PERL_SCAN_DISALLOW_PREFIX
4645 		| PERL_SCAN_SILENT_NON_PORTABLE;
4646 	numlen = lend - l;
4647 	*max = grok_hex((char *)l, &numlen, &flags, NULL);
4648 	if (numlen)
4649 	    l += numlen;
4650 	else    /* If no value here, it is a single element range */
4651 	    *max = *min;
4652 
4653 	/* Non-binary tables have a third entry: what the first element of the
4654 	 * range maps to.  The map for those currently read here is in hex */
4655 	if (wants_value) {
4656 	    if (isBLANK(*l)) {
4657 		++l;
4658                 flags = PERL_SCAN_SILENT_ILLDIGIT
4659                     | PERL_SCAN_DISALLOW_PREFIX
4660                     | PERL_SCAN_SILENT_NON_PORTABLE;
4661                 numlen = lend - l;
4662                 *val = grok_hex((char *)l, &numlen, &flags, NULL);
4663                 if (numlen)
4664                     l += numlen;
4665                 else
4666                     *val = 0;
4667 	    }
4668 	    else {
4669 		*val = 0;
4670 		if (typeto) {
4671 		    /* diag_listed_as: To%s: illegal mapping '%s' */
4672 		    Perl_croak(aTHX_ "%s: illegal mapping '%s'",
4673 				     typestr, l);
4674 		}
4675 	    }
4676 	}
4677 	else
4678 	    *val = 0; /* bits == 1, then any val should be ignored */
4679     }
4680     else { /* Nothing following range min, should be single element with no
4681 	      mapping expected */
4682 	if (wants_value) {
4683 	    *val = 0;
4684 	    if (typeto) {
4685 		/* diag_listed_as: To%s: illegal mapping '%s' */
4686 		Perl_croak(aTHX_ "%s: illegal mapping '%s'", typestr, l);
4687 	    }
4688 	}
4689 	else
4690 	    *val = 0; /* bits == 1, then val should be ignored */
4691     }
4692 
4693     /* Position to next line if any, or EOF */
4694     if (nl)
4695 	l = nl + 1;
4696     else
4697 	l = lend;
4698 
4699     return l;
4700 }
4701 
4702 /* Note:
4703  * Returns a swatch (a bit vector string) for a code point sequence
4704  * that starts from the value C<start> and comprises the number C<span>.
4705  * A C<swash> must be an object created by SWASHNEW (see lib/utf8_heavy.pl).
4706  * Should be used via swash_fetch, which will cache the swatch in C<swash>.
4707  */
4708 STATIC SV*
4709 S_swatch_get(pTHX_ SV* swash, UV start, UV span)
4710 {
4711     SV *swatch;
4712     U8 *l, *lend, *x, *xend, *s;
4713     STRLEN lcur, xcur, scur;
4714     HV *const hv = MUTABLE_HV(SvRV(swash));
4715 
4716     SV** listsvp = NULL; /* The string containing the main body of the table */
4717     SV** extssvp = NULL;
4718     U8* typestr = NULL;
4719     STRLEN bits = 0;
4720     STRLEN octets; /* if bits == 1, then octets == 0 */
4721     UV  none;
4722     UV  end = start + span;
4723 
4724         SV** const bitssvp = hv_fetchs(hv, "BITS", FALSE);
4725         SV** const nonesvp = hv_fetchs(hv, "NONE", FALSE);
4726         SV** const typesvp = hv_fetchs(hv, "TYPE", FALSE);
4727         extssvp = hv_fetchs(hv, "EXTRAS", FALSE);
4728         listsvp = hv_fetchs(hv, "LIST", FALSE);
4729 
4730 	bits  = SvUV(*bitssvp);
4731 	none  = SvUV(*nonesvp);
4732 	typestr = (U8*)SvPV_nolen(*typesvp);
4733     octets = bits >> 3; /* if bits == 1, then octets == 0 */
4734 
4735     PERL_ARGS_ASSERT_SWATCH_GET;
4736 
4737     if (bits != 8 && bits != 16 && bits != 32) {
4738 	Perl_croak(aTHX_ "panic: swatch_get doesn't expect bits %" UVuf,
4739 						 (UV)bits);
4740     }
4741 
4742     /* If overflowed, use the max possible */
4743     if (end < start) {
4744 	end = UV_MAX;
4745 	span = end - start;
4746     }
4747 
4748     /* create and initialize $swatch */
4749     scur   = octets ? (span * octets) : (span + 7) / 8;
4750     swatch = newSV(scur);
4751     SvPOK_on(swatch);
4752     s = (U8*)SvPVX(swatch);
4753     if (octets && none) {
4754 	const U8* const e = s + scur;
4755 	while (s < e) {
4756 	    if (bits == 8)
4757 		*s++ = (U8)(none & 0xff);
4758 	    else if (bits == 16) {
4759 		*s++ = (U8)((none >>  8) & 0xff);
4760 		*s++ = (U8)( none        & 0xff);
4761 	    }
4762 	    else if (bits == 32) {
4763 		*s++ = (U8)((none >> 24) & 0xff);
4764 		*s++ = (U8)((none >> 16) & 0xff);
4765 		*s++ = (U8)((none >>  8) & 0xff);
4766 		*s++ = (U8)( none        & 0xff);
4767 	    }
4768 	}
4769 	*s = '\0';
4770     }
4771     else {
4772 	(void)memzero((U8*)s, scur + 1);
4773     }
4774     SvCUR_set(swatch, scur);
4775     s = (U8*)SvPVX(swatch);
4776 
4777     /* read $swash->{LIST} */
4778     l = (U8*)SvPV(*listsvp, lcur);
4779     lend = l + lcur;
4780     while (l < lend) {
4781 	UV min = 0, max = 0, val = 0, upper;
4782 	l = swash_scan_list_line(l, lend, &min, &max, &val,
4783                                                         cBOOL(octets), typestr);
4784 	if (l > lend) {
4785 	    break;
4786 	}
4787 
4788 	/* If looking for something beyond this range, go try the next one */
4789 	if (max < start)
4790 	    continue;
4791 
4792 	/* <end> is generally 1 beyond where we want to set things, but at the
4793 	 * platform's infinity, where we can't go any higher, we want to
4794 	 * include the code point at <end> */
4795         upper = (max < end)
4796                 ? max
4797                 : (max != UV_MAX || end != UV_MAX)
4798                   ? end - 1
4799                   : end;
4800 
4801 	if (octets) {
4802 	    UV key;
4803 	    if (min < start) {
4804 		if (!none || val < none) {
4805 		    val += start - min;
4806 		}
4807 		min = start;
4808 	    }
4809 	    for (key = min; key <= upper; key++) {
4810 		STRLEN offset;
4811 		/* offset must be non-negative (start <= min <= key < end) */
4812 		offset = octets * (key - start);
4813 		if (bits == 8)
4814 		    s[offset] = (U8)(val & 0xff);
4815 		else if (bits == 16) {
4816 		    s[offset    ] = (U8)((val >>  8) & 0xff);
4817 		    s[offset + 1] = (U8)( val        & 0xff);
4818 		}
4819 		else if (bits == 32) {
4820 		    s[offset    ] = (U8)((val >> 24) & 0xff);
4821 		    s[offset + 1] = (U8)((val >> 16) & 0xff);
4822 		    s[offset + 2] = (U8)((val >>  8) & 0xff);
4823 		    s[offset + 3] = (U8)( val        & 0xff);
4824 		}
4825 
4826 		if (!none || val < none)
4827 		    ++val;
4828 	    }
4829 	}
4830     } /* while */
4831 
4832     /* read $swash->{EXTRAS} */
4833     x = (U8*)SvPV(*extssvp, xcur);
4834     xend = x + xcur;
4835     while (x < xend) {
4836 	STRLEN namelen;
4837 	U8 *namestr;
4838 	SV** othersvp;
4839 	HV* otherhv;
4840 	STRLEN otherbits;
4841 	SV **otherbitssvp, *other;
4842 	U8 *s, *o, *nl;
4843 	STRLEN slen, olen;
4844 
4845 	const U8 opc = *x++;
4846 	if (opc == '\n')
4847 	    continue;
4848 
4849 	nl = (U8*)memchr(x, '\n', xend - x);
4850 
4851 	if (opc != '-' && opc != '+' && opc != '!' && opc != '&') {
4852 	    if (nl) {
4853 		x = nl + 1; /* 1 is length of "\n" */
4854 		continue;
4855 	    }
4856 	    else {
4857 		x = xend; /* to EXTRAS' end at which \n is not found */
4858 		break;
4859 	    }
4860 	}
4861 
4862 	namestr = x;
4863 	if (nl) {
4864 	    namelen = nl - namestr;
4865 	    x = nl + 1;
4866 	}
4867 	else {
4868 	    namelen = xend - namestr;
4869 	    x = xend;
4870 	}
4871 
4872 	othersvp = hv_fetch(hv, (char *)namestr, namelen, FALSE);
4873 	otherhv = MUTABLE_HV(SvRV(*othersvp));
4874 	otherbitssvp = hv_fetchs(otherhv, "BITS", FALSE);
4875 	otherbits = (STRLEN)SvUV(*otherbitssvp);
4876 	if (bits < otherbits)
4877 	    Perl_croak(aTHX_ "panic: swatch_get found swatch size mismatch, "
4878 		       "bits=%" UVuf ", otherbits=%" UVuf, (UV)bits, (UV)otherbits);
4879 
4880 	/* The "other" swatch must be destroyed after. */
4881 	other = swatch_get(*othersvp, start, span);
4882 	o = (U8*)SvPV(other, olen);
4883 
4884 	if (!olen)
4885 	    Perl_croak(aTHX_ "panic: swatch_get got improper swatch");
4886 
4887 	s = (U8*)SvPV(swatch, slen);
4888         {
4889 	    STRLEN otheroctets = otherbits >> 3;
4890 	    STRLEN offset = 0;
4891 	    U8* const send = s + slen;
4892 
4893 	    while (s < send) {
4894 		UV otherval = 0;
4895 
4896 		if (otherbits == 1) {
4897 		    otherval = (o[offset >> 3] >> (offset & 7)) & 1;
4898 		    ++offset;
4899 		}
4900 		else {
4901 		    STRLEN vlen = otheroctets;
4902 		    otherval = *o++;
4903 		    while (--vlen) {
4904 			otherval <<= 8;
4905 			otherval |= *o++;
4906 		    }
4907 		}
4908 
4909 		if (opc == '+' && otherval)
4910 		    NOOP;   /* replace with otherval */
4911 		else if (opc == '!' && !otherval)
4912 		    otherval = 1;
4913 		else if (opc == '-' && otherval)
4914 		    otherval = 0;
4915 		else if (opc == '&' && !otherval)
4916 		    otherval = 0;
4917 		else {
4918 		    s += octets; /* no replacement */
4919 		    continue;
4920 		}
4921 
4922 		if (bits == 8)
4923 		    *s++ = (U8)( otherval & 0xff);
4924 		else if (bits == 16) {
4925 		    *s++ = (U8)((otherval >>  8) & 0xff);
4926 		    *s++ = (U8)( otherval        & 0xff);
4927 		}
4928 		else if (bits == 32) {
4929 		    *s++ = (U8)((otherval >> 24) & 0xff);
4930 		    *s++ = (U8)((otherval >> 16) & 0xff);
4931 		    *s++ = (U8)((otherval >>  8) & 0xff);
4932 		    *s++ = (U8)( otherval        & 0xff);
4933 		}
4934             }
4935 	}
4936 	sv_free(other); /* through with it! */
4937     } /* while */
4938     return swatch;
4939 }
4940 
4941 bool
4942 Perl_check_utf8_print(pTHX_ const U8* s, const STRLEN len)
4943 {
4944     /* May change: warns if surrogates, non-character code points, or
4945      * non-Unicode code points are in 's' which has length 'len' bytes.
4946      * Returns TRUE if none found; FALSE otherwise.  The only other validity
4947      * check is to make sure that this won't exceed the string's length nor
4948      * overflow */
4949 
4950     const U8* const e = s + len;
4951     bool ok = TRUE;
4952 
4953     PERL_ARGS_ASSERT_CHECK_UTF8_PRINT;
4954 
4955     while (s < e) {
4956 	if (UTF8SKIP(s) > len) {
4957 	    Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
4958 			   "%s in %s", unees, PL_op ? OP_DESC(PL_op) : "print");
4959 	    return FALSE;
4960 	}
4961 	if (UNLIKELY(isUTF8_POSSIBLY_PROBLEMATIC(*s))) {
4962 	    if (UNLIKELY(UTF8_IS_SUPER(s, e))) {
4963                 if (   ckWARN_d(WARN_NON_UNICODE)
4964                     || UNLIKELY(0 < does_utf8_overflow(s, s + len,
4965                                                0 /* Don't consider overlongs */
4966                                                )))
4967                 {
4968                     /* A side effect of this function will be to warn */
4969                     (void) utf8n_to_uvchr(s, e - s, NULL, UTF8_WARN_SUPER);
4970                     ok = FALSE;
4971                 }
4972 	    }
4973 	    else if (UNLIKELY(UTF8_IS_SURROGATE(s, e))) {
4974 		if (ckWARN_d(WARN_SURROGATE)) {
4975                     /* This has a different warning than the one the called
4976                      * function would output, so can't just call it, unlike we
4977                      * do for the non-chars and above-unicodes */
4978 		    UV uv = utf8_to_uvchr_buf(s, e, NULL);
4979 		    Perl_warner(aTHX_ packWARN(WARN_SURROGATE),
4980 			"Unicode surrogate U+%04" UVXf " is illegal in UTF-8",
4981                                              uv);
4982 		    ok = FALSE;
4983 		}
4984 	    }
4985 	    else if (   UNLIKELY(UTF8_IS_NONCHAR(s, e))
4986                      && (ckWARN_d(WARN_NONCHAR)))
4987             {
4988                 /* A side effect of this function will be to warn */
4989                 (void) utf8n_to_uvchr(s, e - s, NULL, UTF8_WARN_NONCHAR);
4990 		ok = FALSE;
4991 	    }
4992 	}
4993 	s += UTF8SKIP(s);
4994     }
4995 
4996     return ok;
4997 }
4998 
4999 /*
5000 =for apidoc pv_uni_display
5001 
5002 Build to the scalar C<dsv> a displayable version of the string C<spv>,
5003 length C<len>, the displayable version being at most C<pvlim> bytes long
5004 (if longer, the rest is truncated and C<"..."> will be appended).
5005 
5006 The C<flags> argument can have C<UNI_DISPLAY_ISPRINT> set to display
5007 C<isPRINT()>able characters as themselves, C<UNI_DISPLAY_BACKSLASH>
5008 to display the C<\\[nrfta\\]> as the backslashed versions (like C<"\n">)
5009 (C<UNI_DISPLAY_BACKSLASH> is preferred over C<UNI_DISPLAY_ISPRINT> for C<"\\">).
5010 C<UNI_DISPLAY_QQ> (and its alias C<UNI_DISPLAY_REGEX>) have both
5011 C<UNI_DISPLAY_BACKSLASH> and C<UNI_DISPLAY_ISPRINT> turned on.
5012 
5013 The pointer to the PV of the C<dsv> is returned.
5014 
5015 See also L</sv_uni_display>.
5016 
5017 =cut */
5018 char *
5019 Perl_pv_uni_display(pTHX_ SV *dsv, const U8 *spv, STRLEN len, STRLEN pvlim,
5020                           UV flags)
5021 {
5022     int truncated = 0;
5023     const char *s, *e;
5024 
5025     PERL_ARGS_ASSERT_PV_UNI_DISPLAY;
5026 
5027     SvPVCLEAR(dsv);
5028     SvUTF8_off(dsv);
5029     for (s = (const char *)spv, e = s + len; s < e; s += UTF8SKIP(s)) {
5030 	 UV u;
5031 	  /* This serves double duty as a flag and a character to print after
5032 	     a \ when flags & UNI_DISPLAY_BACKSLASH is true.
5033 	  */
5034 	 char ok = 0;
5035 
5036 	 if (pvlim && SvCUR(dsv) >= pvlim) {
5037 	      truncated++;
5038 	      break;
5039 	 }
5040 	 u = utf8_to_uvchr_buf((U8*)s, (U8*)e, 0);
5041 	 if (u < 256) {
5042 	     const unsigned char c = (unsigned char)u & 0xFF;
5043 	     if (flags & UNI_DISPLAY_BACKSLASH) {
5044 	         switch (c) {
5045 		 case '\n':
5046 		     ok = 'n'; break;
5047 		 case '\r':
5048 		     ok = 'r'; break;
5049 		 case '\t':
5050 		     ok = 't'; break;
5051 		 case '\f':
5052 		     ok = 'f'; break;
5053 		 case '\a':
5054 		     ok = 'a'; break;
5055 		 case '\\':
5056 		     ok = '\\'; break;
5057 		 default: break;
5058 		 }
5059 		 if (ok) {
5060 		     const char string = ok;
5061 		     sv_catpvs(dsv, "\\");
5062 		     sv_catpvn(dsv, &string, 1);
5063 		 }
5064 	     }
5065 	     /* isPRINT() is the locale-blind version. */
5066 	     if (!ok && (flags & UNI_DISPLAY_ISPRINT) && isPRINT(c)) {
5067 		 const char string = c;
5068 		 sv_catpvn(dsv, &string, 1);
5069 		 ok = 1;
5070 	     }
5071 	 }
5072 	 if (!ok)
5073 	     Perl_sv_catpvf(aTHX_ dsv, "\\x{%" UVxf "}", u);
5074     }
5075     if (truncated)
5076 	 sv_catpvs(dsv, "...");
5077 
5078     return SvPVX(dsv);
5079 }
5080 
5081 /*
5082 =for apidoc sv_uni_display
5083 
5084 Build to the scalar C<dsv> a displayable version of the scalar C<sv>,
5085 the displayable version being at most C<pvlim> bytes long
5086 (if longer, the rest is truncated and "..." will be appended).
5087 
5088 The C<flags> argument is as in L</pv_uni_display>().
5089 
5090 The pointer to the PV of the C<dsv> is returned.
5091 
5092 =cut
5093 */
5094 char *
5095 Perl_sv_uni_display(pTHX_ SV *dsv, SV *ssv, STRLEN pvlim, UV flags)
5096 {
5097     const char * const ptr =
5098         isREGEXP(ssv) ? RX_WRAPPED((REGEXP*)ssv) : SvPVX_const(ssv);
5099 
5100     PERL_ARGS_ASSERT_SV_UNI_DISPLAY;
5101 
5102     return Perl_pv_uni_display(aTHX_ dsv, (const U8*)ptr,
5103 				SvCUR(ssv), pvlim, flags);
5104 }
5105 
5106 /*
5107 =for apidoc foldEQ_utf8
5108 
5109 Returns true if the leading portions of the strings C<s1> and C<s2> (either or
5110 both of which may be in UTF-8) are the same case-insensitively; false
5111 otherwise.  How far into the strings to compare is determined by other input
5112 parameters.
5113 
5114 If C<u1> is true, the string C<s1> is assumed to be in UTF-8-encoded Unicode;
5115 otherwise it is assumed to be in native 8-bit encoding.  Correspondingly for
5116 C<u2> with respect to C<s2>.
5117 
5118 If the byte length C<l1> is non-zero, it says how far into C<s1> to check for
5119 fold equality.  In other words, C<s1>+C<l1> will be used as a goal to reach.
5120 The scan will not be considered to be a match unless the goal is reached, and
5121 scanning won't continue past that goal.  Correspondingly for C<l2> with respect
5122 to C<s2>.
5123 
5124 If C<pe1> is non-C<NULL> and the pointer it points to is not C<NULL>, that
5125 pointer is considered an end pointer to the position 1 byte past the maximum
5126 point in C<s1> beyond which scanning will not continue under any circumstances.
5127 (This routine assumes that UTF-8 encoded input strings are not malformed;
5128 malformed input can cause it to read past C<pe1>).  This means that if both
5129 C<l1> and C<pe1> are specified, and C<pe1> is less than C<s1>+C<l1>, the match
5130 will never be successful because it can never
5131 get as far as its goal (and in fact is asserted against).  Correspondingly for
5132 C<pe2> with respect to C<s2>.
5133 
5134 At least one of C<s1> and C<s2> must have a goal (at least one of C<l1> and
5135 C<l2> must be non-zero), and if both do, both have to be
5136 reached for a successful match.   Also, if the fold of a character is multiple
5137 characters, all of them must be matched (see tr21 reference below for
5138 'folding').
5139 
5140 Upon a successful match, if C<pe1> is non-C<NULL>,
5141 it will be set to point to the beginning of the I<next> character of C<s1>
5142 beyond what was matched.  Correspondingly for C<pe2> and C<s2>.
5143 
5144 For case-insensitiveness, the "casefolding" of Unicode is used
5145 instead of upper/lowercasing both the characters, see
5146 L<http://www.unicode.org/unicode/reports/tr21/> (Case Mappings).
5147 
5148 =cut */
5149 
5150 /* A flags parameter has been added which may change, and hence isn't
5151  * externally documented.  Currently it is:
5152  *  0 for as-documented above
5153  *  FOLDEQ_UTF8_NOMIX_ASCII meaning that if a non-ASCII character folds to an
5154 			    ASCII one, to not match
5155  *  FOLDEQ_LOCALE	    is set iff the rules from the current underlying
5156  *	                    locale are to be used.
5157  *  FOLDEQ_S1_ALREADY_FOLDED  s1 has already been folded before calling this
5158  *                          routine.  This allows that step to be skipped.
5159  *                          Currently, this requires s1 to be encoded as UTF-8
5160  *                          (u1 must be true), which is asserted for.
5161  *  FOLDEQ_S1_FOLDS_SANE    With either NOMIX_ASCII or LOCALE, no folds may
5162  *                          cross certain boundaries.  Hence, the caller should
5163  *                          let this function do the folding instead of
5164  *                          pre-folding.  This code contains an assertion to
5165  *                          that effect.  However, if the caller knows what
5166  *                          it's doing, it can pass this flag to indicate that,
5167  *                          and the assertion is skipped.
5168  *  FOLDEQ_S2_ALREADY_FOLDED  Similar to FOLDEQ_S1_ALREADY_FOLDED, but applies
5169  *                          to s2, and s2 doesn't have to be UTF-8 encoded.
5170  *                          This introduces an asymmetry to save a few branches
5171  *                          in a loop.  Currently, this is not a problem, as
5172  *                          never are both inputs pre-folded.  Simply call this
5173  *                          function with the pre-folded one as the second
5174  *                          string.
5175  *  FOLDEQ_S2_FOLDS_SANE
5176  */
5177 I32
5178 Perl_foldEQ_utf8_flags(pTHX_ const char *s1, char **pe1, UV l1, bool u1,
5179                              const char *s2, char **pe2, UV l2, bool u2,
5180                              U32 flags)
5181 {
5182     const U8 *p1  = (const U8*)s1; /* Point to current char */
5183     const U8 *p2  = (const U8*)s2;
5184     const U8 *g1 = NULL;       /* goal for s1 */
5185     const U8 *g2 = NULL;
5186     const U8 *e1 = NULL;       /* Don't scan s1 past this */
5187     U8 *f1 = NULL;             /* Point to current folded */
5188     const U8 *e2 = NULL;
5189     U8 *f2 = NULL;
5190     STRLEN n1 = 0, n2 = 0;              /* Number of bytes in current char */
5191     U8 foldbuf1[UTF8_MAXBYTES_CASE+1];
5192     U8 foldbuf2[UTF8_MAXBYTES_CASE+1];
5193     U8 flags_for_folder = FOLD_FLAGS_FULL;
5194 
5195     PERL_ARGS_ASSERT_FOLDEQ_UTF8_FLAGS;
5196 
5197     assert( ! (             (flags & (FOLDEQ_UTF8_NOMIX_ASCII | FOLDEQ_LOCALE))
5198                && ((        (flags &  FOLDEQ_S1_ALREADY_FOLDED)
5199                         && !(flags &  FOLDEQ_S1_FOLDS_SANE))
5200                     || (    (flags &  FOLDEQ_S2_ALREADY_FOLDED)
5201                         && !(flags &  FOLDEQ_S2_FOLDS_SANE)))));
5202     /* The algorithm is to trial the folds without regard to the flags on
5203      * the first line of the above assert(), and then see if the result
5204      * violates them.  This means that the inputs can't be pre-folded to a
5205      * violating result, hence the assert.  This could be changed, with the
5206      * addition of extra tests here for the already-folded case, which would
5207      * slow it down.  That cost is more than any possible gain for when these
5208      * flags are specified, as the flags indicate /il or /iaa matching which
5209      * is less common than /iu, and I (khw) also believe that real-world /il
5210      * and /iaa matches are most likely to involve code points 0-255, and this
5211      * function only under rare conditions gets called for 0-255. */
5212 
5213     if (flags & FOLDEQ_LOCALE) {
5214         if (IN_UTF8_CTYPE_LOCALE) {
5215             if (UNLIKELY(PL_in_utf8_turkic_locale)) {
5216                 flags_for_folder |= FOLD_FLAGS_LOCALE;
5217             }
5218             else {
5219                 flags &= ~FOLDEQ_LOCALE;
5220             }
5221         }
5222         else {
5223             flags_for_folder |= FOLD_FLAGS_LOCALE;
5224         }
5225     }
5226     if (flags & FOLDEQ_UTF8_NOMIX_ASCII) {
5227         flags_for_folder |= FOLD_FLAGS_NOMIX_ASCII;
5228     }
5229 
5230     if (pe1) {
5231         e1 = *(U8**)pe1;
5232     }
5233 
5234     if (l1) {
5235         g1 = (const U8*)s1 + l1;
5236     }
5237 
5238     if (pe2) {
5239         e2 = *(U8**)pe2;
5240     }
5241 
5242     if (l2) {
5243         g2 = (const U8*)s2 + l2;
5244     }
5245 
5246     /* Must have at least one goal */
5247     assert(g1 || g2);
5248 
5249     if (g1) {
5250 
5251         /* Will never match if goal is out-of-bounds */
5252         assert(! e1  || e1 >= g1);
5253 
5254         /* Here, there isn't an end pointer, or it is beyond the goal.  We
5255         * only go as far as the goal */
5256         e1 = g1;
5257     }
5258     else {
5259 	assert(e1);    /* Must have an end for looking at s1 */
5260     }
5261 
5262     /* Same for goal for s2 */
5263     if (g2) {
5264         assert(! e2  || e2 >= g2);
5265         e2 = g2;
5266     }
5267     else {
5268 	assert(e2);
5269     }
5270 
5271     /* If both operands are already folded, we could just do a memEQ on the
5272      * whole strings at once, but it would be better if the caller realized
5273      * this and didn't even call us */
5274 
5275     /* Look through both strings, a character at a time */
5276     while (p1 < e1 && p2 < e2) {
5277 
5278         /* If at the beginning of a new character in s1, get its fold to use
5279 	 * and the length of the fold. */
5280         if (n1 == 0) {
5281 	    if (flags & FOLDEQ_S1_ALREADY_FOLDED) {
5282 		f1 = (U8 *) p1;
5283                 assert(u1);
5284 		n1 = UTF8SKIP(f1);
5285 	    }
5286 	    else {
5287                 if (isASCII(*p1) && ! (flags & FOLDEQ_LOCALE)) {
5288 
5289                     /* We have to forbid mixing ASCII with non-ASCII if the
5290                      * flags so indicate.  And, we can short circuit having to
5291                      * call the general functions for this common ASCII case,
5292                      * all of whose non-locale folds are also ASCII, and hence
5293                      * UTF-8 invariants, so the UTF8ness of the strings is not
5294                      * relevant. */
5295                     if ((flags & FOLDEQ_UTF8_NOMIX_ASCII) && ! isASCII(*p2)) {
5296                         return 0;
5297                     }
5298                     n1 = 1;
5299                     *foldbuf1 = toFOLD(*p1);
5300                 }
5301                 else if (u1) {
5302                     _toFOLD_utf8_flags(p1, e1, foldbuf1, &n1, flags_for_folder);
5303                 }
5304                 else {  /* Not UTF-8, get UTF-8 fold */
5305                     _to_uni_fold_flags(*p1, foldbuf1, &n1, flags_for_folder);
5306                 }
5307                 f1 = foldbuf1;
5308             }
5309         }
5310 
5311         if (n2 == 0) {    /* Same for s2 */
5312 	    if (flags & FOLDEQ_S2_ALREADY_FOLDED) {
5313 
5314                 /* Point to the already-folded character.  But for non-UTF-8
5315                  * variants, convert to UTF-8 for the algorithm below */
5316 		if (UTF8_IS_INVARIANT(*p2)) {
5317                     f2 = (U8 *) p2;
5318                     n2 = 1;
5319                 }
5320                 else if (u2) {
5321                     f2 = (U8 *) p2;
5322                     n2 = UTF8SKIP(f2);
5323                 }
5324                 else {
5325                     foldbuf2[0] = UTF8_EIGHT_BIT_HI(*p2);
5326                     foldbuf2[1] = UTF8_EIGHT_BIT_LO(*p2);
5327                     f2 = foldbuf2;
5328                     n2 = 2;
5329                 }
5330 	    }
5331 	    else {
5332                 if (isASCII(*p2) && ! (flags & FOLDEQ_LOCALE)) {
5333                     if ((flags & FOLDEQ_UTF8_NOMIX_ASCII) && ! isASCII(*p1)) {
5334                         return 0;
5335                     }
5336                     n2 = 1;
5337                     *foldbuf2 = toFOLD(*p2);
5338                 }
5339                 else if (u2) {
5340                     _toFOLD_utf8_flags(p2, e2, foldbuf2, &n2, flags_for_folder);
5341                 }
5342                 else {
5343                     _to_uni_fold_flags(*p2, foldbuf2, &n2, flags_for_folder);
5344                 }
5345                 f2 = foldbuf2;
5346 	    }
5347         }
5348 
5349 	/* Here f1 and f2 point to the beginning of the strings to compare.
5350 	 * These strings are the folds of the next character from each input
5351 	 * string, stored in UTF-8. */
5352 
5353         /* While there is more to look for in both folds, see if they
5354         * continue to match */
5355         while (n1 && n2) {
5356             U8 fold_length = UTF8SKIP(f1);
5357             if (fold_length != UTF8SKIP(f2)
5358                 || (fold_length == 1 && *f1 != *f2) /* Short circuit memNE
5359                                                        function call for single
5360                                                        byte */
5361                 || memNE((char*)f1, (char*)f2, fold_length))
5362             {
5363                 return 0; /* mismatch */
5364             }
5365 
5366             /* Here, they matched, advance past them */
5367             n1 -= fold_length;
5368             f1 += fold_length;
5369             n2 -= fold_length;
5370             f2 += fold_length;
5371         }
5372 
5373         /* When reach the end of any fold, advance the input past it */
5374         if (n1 == 0) {
5375             p1 += u1 ? UTF8SKIP(p1) : 1;
5376         }
5377         if (n2 == 0) {
5378             p2 += u2 ? UTF8SKIP(p2) : 1;
5379         }
5380     } /* End of loop through both strings */
5381 
5382     /* A match is defined by each scan that specified an explicit length
5383     * reaching its final goal, and the other not having matched a partial
5384     * character (which can happen when the fold of a character is more than one
5385     * character). */
5386     if (! ((g1 == 0 || p1 == g1) && (g2 == 0 || p2 == g2)) || n1 || n2) {
5387         return 0;
5388     }
5389 
5390     /* Successful match.  Set output pointers */
5391     if (pe1) {
5392         *pe1 = (char*)p1;
5393     }
5394     if (pe2) {
5395         *pe2 = (char*)p2;
5396     }
5397     return 1;
5398 }
5399 
5400 /* XXX The next two functions should likely be moved to mathoms.c once all
5401  * occurrences of them are removed from the core; some cpan-upstream modules
5402  * still use them */
5403 
5404 U8 *
5405 Perl_uvuni_to_utf8(pTHX_ U8 *d, UV uv)
5406 {
5407     PERL_ARGS_ASSERT_UVUNI_TO_UTF8;
5408 
5409     return uvoffuni_to_utf8_flags(d, uv, 0);
5410 }
5411 
5412 /*
5413 =for apidoc utf8n_to_uvuni
5414 
5415 Instead use L</utf8_to_uvchr_buf>, or rarely, L</utf8n_to_uvchr>.
5416 
5417 This function was useful for code that wanted to handle both EBCDIC and
5418 ASCII platforms with Unicode properties, but starting in Perl v5.20, the
5419 distinctions between the platforms have mostly been made invisible to most
5420 code, so this function is quite unlikely to be what you want.  If you do need
5421 this precise functionality, use instead
5422 C<L<NATIVE_TO_UNI(utf8_to_uvchr_buf(...))|/utf8_to_uvchr_buf>>
5423 or C<L<NATIVE_TO_UNI(utf8n_to_uvchr(...))|/utf8n_to_uvchr>>.
5424 
5425 =cut
5426 */
5427 
5428 UV
5429 Perl_utf8n_to_uvuni(pTHX_ const U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
5430 {
5431     PERL_ARGS_ASSERT_UTF8N_TO_UVUNI;
5432 
5433     return NATIVE_TO_UNI(utf8n_to_uvchr(s, curlen, retlen, flags));
5434 }
5435 
5436 /*
5437 =for apidoc uvuni_to_utf8_flags
5438 
5439 Instead you almost certainly want to use L</uvchr_to_utf8> or
5440 L</uvchr_to_utf8_flags>.
5441 
5442 This function is a deprecated synonym for L</uvoffuni_to_utf8_flags>,
5443 which itself, while not deprecated, should be used only in isolated
5444 circumstances.  These functions were useful for code that wanted to handle
5445 both EBCDIC and ASCII platforms with Unicode properties, but starting in Perl
5446 v5.20, the distinctions between the platforms have mostly been made invisible
5447 to most code, so this function is quite unlikely to be what you want.
5448 
5449 =cut
5450 */
5451 
5452 U8 *
5453 Perl_uvuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
5454 {
5455     PERL_ARGS_ASSERT_UVUNI_TO_UTF8_FLAGS;
5456 
5457     return uvoffuni_to_utf8_flags(d, uv, flags);
5458 }
5459 
5460 /*
5461 =for apidoc utf8_to_uvchr
5462 
5463 Returns the native code point of the first character in the string C<s>
5464 which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
5465 length, in bytes, of that character.
5466 
5467 Some, but not all, UTF-8 malformations are detected, and in fact, some
5468 malformed input could cause reading beyond the end of the input buffer, which
5469 is why this function is deprecated.  Use L</utf8_to_uvchr_buf> instead.
5470 
5471 If C<s> points to one of the detected malformations, and UTF8 warnings are
5472 enabled, zero is returned and C<*retlen> is set (if C<retlen> isn't
5473 C<NULL>) to -1.  If those warnings are off, the computed value if well-defined (or
5474 the Unicode REPLACEMENT CHARACTER, if not) is silently returned, and C<*retlen>
5475 is set (if C<retlen> isn't NULL) so that (S<C<s> + C<*retlen>>) is the
5476 next possible position in C<s> that could begin a non-malformed character.
5477 See L</utf8n_to_uvchr> for details on when the REPLACEMENT CHARACTER is returned.
5478 
5479 =cut
5480 */
5481 
5482 UV
5483 Perl_utf8_to_uvchr(pTHX_ const U8 *s, STRLEN *retlen)
5484 {
5485     PERL_ARGS_ASSERT_UTF8_TO_UVCHR;
5486 
5487     /* This function is unsafe if malformed UTF-8 input is given it, which is
5488      * why the function is deprecated.  If the first byte of the input
5489      * indicates that there are more bytes remaining in the sequence that forms
5490      * the character than there are in the input buffer, it can read past the
5491      * end.  But we can make it safe if the input string happens to be
5492      * NUL-terminated, as many strings in Perl are, by refusing to read past a
5493      * NUL.  A NUL indicates the start of the next character anyway.  If the
5494      * input isn't NUL-terminated, the function remains unsafe, as it always
5495      * has been.
5496      *
5497      * An initial NUL has to be handled separately, but all ASCIIs can be
5498      * handled the same way, speeding up this common case */
5499 
5500     if (UTF8_IS_INVARIANT(*s)) {  /* Assumes 's' contains at least 1 byte */
5501         if (retlen) {
5502             *retlen = 1;
5503         }
5504         return (UV) *s;
5505     }
5506 
5507     return utf8_to_uvchr_buf(s,
5508                              s + my_strnlen((char *) s, UTF8SKIP(s)),
5509                              retlen);
5510 }
5511 
5512 /*
5513  * ex: set ts=8 sts=4 sw=4 et:
5514  */
5515