xref: /openbsd-src/gnu/usr.bin/perl/utf8.c (revision 8500990981f885cbe5e6a4958549cacc238b5ae6)
1 /*    utf8.c
2  *
3  *    Copyright (C) 2000, 2001, 2002, 2003, by Larry Wall and others
4  *
5  *    You may distribute under the terms of either the GNU General Public
6  *    License or the Artistic License, as specified in the README file.
7  *
8  */
9 
10 /*
11  * 'What a fix!' said Sam. 'That's the one place in all the lands we've ever
12  * heard of that we don't want to see any closer; and that's the one place
13  * we're trying to get to!  And that's just where we can't get, nohow.'
14  *
15  * 'Well do I understand your speech,' he answered in the same language;
16  * 'yet few strangers do so.  Why then do you not speak in the Common Tongue,
17  * as is the custom in the West, if you wish to be answered?'
18  *
19  * ...the travellers perceived that the floor was paved with stones of many
20  * hues; branching runes and strange devices intertwined beneath their feet.
21  */
22 
23 #include "EXTERN.h"
24 #define PERL_IN_UTF8_C
25 #include "perl.h"
26 
27 static char unees[] = "Malformed UTF-8 character (unexpected end of string)";
28 
29 /*
30 =head1 Unicode Support
31 
32 =for apidoc A|U8 *|uvuni_to_utf8_flags|U8 *d|UV uv|UV flags
33 
34 Adds the UTF-8 representation of the Unicode codepoint C<uv> to the end
35 of the string C<d>; C<d> should be have at least C<UTF8_MAXLEN+1> free
36 bytes available. The return value is the pointer to the byte after the
37 end of the new character. In other words,
38 
39     d = uvuni_to_utf8_flags(d, uv, flags);
40 
41 or, in most cases,
42 
43     d = uvuni_to_utf8(d, uv);
44 
45 (which is equivalent to)
46 
47     d = uvuni_to_utf8_flags(d, uv, 0);
48 
49 is the recommended Unicode-aware way of saying
50 
51     *(d++) = uv;
52 
53 =cut
54 */
55 
56 U8 *
57 Perl_uvuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
58 {
59     if (ckWARN(WARN_UTF8)) {
60 	 if (UNICODE_IS_SURROGATE(uv) &&
61 	     !(flags & UNICODE_ALLOW_SURROGATE))
62 	      Perl_warner(aTHX_ packWARN(WARN_UTF8), "UTF-16 surrogate 0x%04"UVxf, uv);
63 	 else if (
64 		  ((uv >= 0xFDD0 && uv <= 0xFDEF &&
65 		    !(flags & UNICODE_ALLOW_FDD0))
66 		   ||
67 		   ((uv & 0xFFFE) == 0xFFFE && /* Either FFFE or FFFF. */
68 		    !(flags & UNICODE_ALLOW_FFFF))) &&
69 		  /* UNICODE_ALLOW_SUPER includes
70 		   * FFFEs and FFFFs beyond 0x10FFFF. */
71 		  ((uv <= PERL_UNICODE_MAX) ||
72 		   !(flags & UNICODE_ALLOW_SUPER))
73 		  )
74 	      Perl_warner(aTHX_ packWARN(WARN_UTF8),
75 			 "Unicode character 0x%04"UVxf" is illegal", uv);
76     }
77     if (UNI_IS_INVARIANT(uv)) {
78 	*d++ = (U8)UTF_TO_NATIVE(uv);
79 	return d;
80     }
81 #if defined(EBCDIC)
82     else {
83 	STRLEN len  = UNISKIP(uv);
84 	U8 *p = d+len-1;
85 	while (p > d) {
86 	    *p-- = (U8)UTF_TO_NATIVE((uv & UTF_CONTINUATION_MASK) | UTF_CONTINUATION_MARK);
87 	    uv >>= UTF_ACCUMULATION_SHIFT;
88 	}
89 	*p = (U8)UTF_TO_NATIVE((uv & UTF_START_MASK(len)) | UTF_START_MARK(len));
90 	return d+len;
91     }
92 #else /* Non loop style */
93     if (uv < 0x800) {
94 	*d++ = (U8)(( uv >>  6)         | 0xc0);
95 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
96 	return d;
97     }
98     if (uv < 0x10000) {
99 	*d++ = (U8)(( uv >> 12)         | 0xe0);
100 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
101 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
102 	return d;
103     }
104     if (uv < 0x200000) {
105 	*d++ = (U8)(( uv >> 18)         | 0xf0);
106 	*d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
107 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
108 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
109 	return d;
110     }
111     if (uv < 0x4000000) {
112 	*d++ = (U8)(( uv >> 24)         | 0xf8);
113 	*d++ = (U8)(((uv >> 18) & 0x3f) | 0x80);
114 	*d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
115 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
116 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
117 	return d;
118     }
119     if (uv < 0x80000000) {
120 	*d++ = (U8)(( uv >> 30)         | 0xfc);
121 	*d++ = (U8)(((uv >> 24) & 0x3f) | 0x80);
122 	*d++ = (U8)(((uv >> 18) & 0x3f) | 0x80);
123 	*d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
124 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
125 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
126 	return d;
127     }
128 #ifdef HAS_QUAD
129     if (uv < UTF8_QUAD_MAX)
130 #endif
131     {
132 	*d++ =                            0xfe;	/* Can't match U+FEFF! */
133 	*d++ = (U8)(((uv >> 30) & 0x3f) | 0x80);
134 	*d++ = (U8)(((uv >> 24) & 0x3f) | 0x80);
135 	*d++ = (U8)(((uv >> 18) & 0x3f) | 0x80);
136 	*d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
137 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
138 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
139 	return d;
140     }
141 #ifdef HAS_QUAD
142     {
143 	*d++ =                            0xff;		/* Can't match U+FFFE! */
144 	*d++ =                            0x80;		/* 6 Reserved bits */
145 	*d++ = (U8)(((uv >> 60) & 0x0f) | 0x80);	/* 2 Reserved bits */
146 	*d++ = (U8)(((uv >> 54) & 0x3f) | 0x80);
147 	*d++ = (U8)(((uv >> 48) & 0x3f) | 0x80);
148 	*d++ = (U8)(((uv >> 42) & 0x3f) | 0x80);
149 	*d++ = (U8)(((uv >> 36) & 0x3f) | 0x80);
150 	*d++ = (U8)(((uv >> 30) & 0x3f) | 0x80);
151 	*d++ = (U8)(((uv >> 24) & 0x3f) | 0x80);
152 	*d++ = (U8)(((uv >> 18) & 0x3f) | 0x80);
153 	*d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
154 	*d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
155 	*d++ = (U8)(( uv        & 0x3f) | 0x80);
156 	return d;
157     }
158 #endif
159 #endif /* Loop style */
160 }
161 
162 U8 *
163 Perl_uvuni_to_utf8(pTHX_ U8 *d, UV uv)
164 {
165     return Perl_uvuni_to_utf8_flags(aTHX_ d, uv, 0);
166 }
167 
168 
169 /*
170 =for apidoc A|STRLEN|is_utf8_char|U8 *s
171 
172 Tests if some arbitrary number of bytes begins in a valid UTF-8
173 character.  Note that an INVARIANT (i.e. ASCII) character is a valid
174 UTF-8 character.  The actual number of bytes in the UTF-8 character
175 will be returned if it is valid, otherwise 0.
176 
177 =cut */
178 STRLEN
179 Perl_is_utf8_char(pTHX_ U8 *s)
180 {
181     U8 u = *s;
182     STRLEN slen, len;
183     UV uv, ouv;
184 
185     if (UTF8_IS_INVARIANT(u))
186 	return 1;
187 
188     if (!UTF8_IS_START(u))
189 	return 0;
190 
191     len = UTF8SKIP(s);
192 
193     if (len < 2 || !UTF8_IS_CONTINUATION(s[1]))
194 	return 0;
195 
196     slen = len - 1;
197     s++;
198     u &= UTF_START_MASK(len);
199     uv  = u;
200     ouv = uv;
201     while (slen--) {
202 	if (!UTF8_IS_CONTINUATION(*s))
203 	    return 0;
204 	uv = UTF8_ACCUMULATE(uv, *s);
205 	if (uv < ouv)
206 	    return 0;
207 	ouv = uv;
208 	s++;
209     }
210 
211     if ((STRLEN)UNISKIP(uv) < len)
212 	return 0;
213 
214     return len;
215 }
216 
217 /*
218 =for apidoc A|bool|is_utf8_string|U8 *s|STRLEN len
219 
220 Returns true if first C<len> bytes of the given string form a valid
221 UTF-8 string, false otherwise.  Note that 'a valid UTF-8 string' does
222 not mean 'a string that contains code points above 0x7F encoded in UTF-8'
223 because a valid ASCII string is a valid UTF-8 string.
224 
225 =cut
226 */
227 
228 bool
229 Perl_is_utf8_string(pTHX_ U8 *s, STRLEN len)
230 {
231     U8* x = s;
232     U8* send;
233     STRLEN c;
234 
235     if (!len)
236 	len = strlen((char *)s);
237     send = s + len;
238 
239     while (x < send) {
240 	 /* Inline the easy bits of is_utf8_char() here for speed... */
241 	 if (UTF8_IS_INVARIANT(*x))
242 	      c = 1;
243 	 else if (!UTF8_IS_START(*x))
244 	      return FALSE;
245 	 else {
246 	      /* ... and call is_utf8_char() only if really needed. */
247 	      c = is_utf8_char(x);
248 	      if (!c)
249 		   return FALSE;
250 	 }
251         x += c;
252     }
253     if (x != send)
254 	return FALSE;
255 
256     return TRUE;
257 }
258 
259 /*
260 =for apidoc A|bool|is_utf8_string_loc|U8 *s|STRLEN len|U8 **p
261 
262 Like is_ut8_string but store the location of the failure in
263 the last argument.
264 
265 =cut
266 */
267 
268 bool
269 Perl_is_utf8_string_loc(pTHX_ U8 *s, STRLEN len, U8 **p)
270 {
271     U8* x = s;
272     U8* send;
273     STRLEN c;
274 
275     if (!len)
276 	len = strlen((char *)s);
277     send = s + len;
278 
279     while (x < send) {
280 	 /* Inline the easy bits of is_utf8_char() here for speed... */
281 	 if (UTF8_IS_INVARIANT(*x))
282 	      c = 1;
283 	 else if (!UTF8_IS_START(*x)) {
284 	      if (p)
285 		  *p = x;
286 	      return FALSE;
287 	 }
288 	 else {
289 	      /* ... and call is_utf8_char() only if really needed. */
290 	      c = is_utf8_char(x);
291 	      if (!c) {
292 		   if (p)
293 		      *p = x;
294 		   return FALSE;
295 	      }
296 	 }
297         x += c;
298     }
299     if (x != send) {
300        if (p)
301 	   *p = x;
302 	return FALSE;
303     }
304 
305     return TRUE;
306 }
307 
308 /*
309 =for apidoc A|UV|utf8n_to_uvuni|U8 *s|STRLEN curlen|STRLEN *retlen|U32 flags
310 
311 Bottom level UTF-8 decode routine.
312 Returns the unicode code point value of the first character in the string C<s>
313 which is assumed to be in UTF-8 encoding and no longer than C<curlen>;
314 C<retlen> will be set to the length, in bytes, of that character.
315 
316 If C<s> does not point to a well-formed UTF-8 character, the behaviour
317 is dependent on the value of C<flags>: if it contains UTF8_CHECK_ONLY,
318 it is assumed that the caller will raise a warning, and this function
319 will silently just set C<retlen> to C<-1> and return zero.  If the
320 C<flags> does not contain UTF8_CHECK_ONLY, warnings about
321 malformations will be given, C<retlen> will be set to the expected
322 length of the UTF-8 character in bytes, and zero will be returned.
323 
324 The C<flags> can also contain various flags to allow deviations from
325 the strict UTF-8 encoding (see F<utf8.h>).
326 
327 Most code should use utf8_to_uvchr() rather than call this directly.
328 
329 =cut
330 */
331 
332 UV
333 Perl_utf8n_to_uvuni(pTHX_ U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
334 {
335     U8 *s0 = s;
336     UV uv = *s, ouv = 0;
337     STRLEN len = 1;
338     bool dowarn = ckWARN_d(WARN_UTF8);
339     UV startbyte = *s;
340     STRLEN expectlen = 0;
341     U32 warning = 0;
342 
343 /* This list is a superset of the UTF8_ALLOW_XXX. */
344 
345 #define UTF8_WARN_EMPTY				 1
346 #define UTF8_WARN_CONTINUATION			 2
347 #define UTF8_WARN_NON_CONTINUATION	 	 3
348 #define UTF8_WARN_FE_FF				 4
349 #define UTF8_WARN_SHORT				 5
350 #define UTF8_WARN_OVERFLOW			 6
351 #define UTF8_WARN_SURROGATE			 7
352 #define UTF8_WARN_LONG				 8
353 #define UTF8_WARN_FFFF				 9 /* Also FFFE. */
354 
355     if (curlen == 0 &&
356 	!(flags & UTF8_ALLOW_EMPTY)) {
357 	warning = UTF8_WARN_EMPTY;
358 	goto malformed;
359     }
360 
361     if (UTF8_IS_INVARIANT(uv)) {
362 	if (retlen)
363 	    *retlen = 1;
364 	return (UV) (NATIVE_TO_UTF(*s));
365     }
366 
367     if (UTF8_IS_CONTINUATION(uv) &&
368 	!(flags & UTF8_ALLOW_CONTINUATION)) {
369 	warning = UTF8_WARN_CONTINUATION;
370 	goto malformed;
371     }
372 
373     if (UTF8_IS_START(uv) && curlen > 1 && !UTF8_IS_CONTINUATION(s[1]) &&
374 	!(flags & UTF8_ALLOW_NON_CONTINUATION)) {
375 	warning = UTF8_WARN_NON_CONTINUATION;
376 	goto malformed;
377     }
378 
379 #ifdef EBCDIC
380     uv = NATIVE_TO_UTF(uv);
381 #else
382     if ((uv == 0xfe || uv == 0xff) &&
383 	!(flags & UTF8_ALLOW_FE_FF)) {
384 	warning = UTF8_WARN_FE_FF;
385 	goto malformed;
386     }
387 #endif
388 
389     if      (!(uv & 0x20))	{ len =  2; uv &= 0x1f; }
390     else if (!(uv & 0x10))	{ len =  3; uv &= 0x0f; }
391     else if (!(uv & 0x08))	{ len =  4; uv &= 0x07; }
392     else if (!(uv & 0x04))	{ len =  5; uv &= 0x03; }
393 #ifdef EBCDIC
394     else if (!(uv & 0x02))	{ len =  6; uv &= 0x01; }
395     else			{ len =  7; uv &= 0x01; }
396 #else
397     else if (!(uv & 0x02))	{ len =  6; uv &= 0x01; }
398     else if (!(uv & 0x01))	{ len =  7; uv = 0; }
399     else			{ len = 13; uv = 0; } /* whoa! */
400 #endif
401 
402     if (retlen)
403 	*retlen = len;
404 
405     expectlen = len;
406 
407     if ((curlen < expectlen) &&
408 	!(flags & UTF8_ALLOW_SHORT)) {
409 	warning = UTF8_WARN_SHORT;
410 	goto malformed;
411     }
412 
413     len--;
414     s++;
415     ouv = uv;
416 
417     while (len--) {
418 	if (!UTF8_IS_CONTINUATION(*s) &&
419 	    !(flags & UTF8_ALLOW_NON_CONTINUATION)) {
420 	    s--;
421 	    warning = UTF8_WARN_NON_CONTINUATION;
422 	    goto malformed;
423 	}
424 	else
425 	    uv = UTF8_ACCUMULATE(uv, *s);
426 	if (!(uv > ouv)) {
427 	    /* These cannot be allowed. */
428 	    if (uv == ouv) {
429 		if (!(flags & UTF8_ALLOW_LONG)) {
430 		    warning = UTF8_WARN_LONG;
431 		    goto malformed;
432 		}
433 	    }
434 	    else { /* uv < ouv */
435 		/* This cannot be allowed. */
436 		warning = UTF8_WARN_OVERFLOW;
437 		goto malformed;
438 	    }
439 	}
440 	s++;
441 	ouv = uv;
442     }
443 
444     if (UNICODE_IS_SURROGATE(uv) &&
445 	!(flags & UTF8_ALLOW_SURROGATE)) {
446 	warning = UTF8_WARN_SURROGATE;
447 	goto malformed;
448     } else if ((expectlen > (STRLEN)UNISKIP(uv)) &&
449 	       !(flags & UTF8_ALLOW_LONG)) {
450 	warning = UTF8_WARN_LONG;
451 	goto malformed;
452     } else if (UNICODE_IS_ILLEGAL(uv) &&
453 	       !(flags & UTF8_ALLOW_FFFF)) {
454 	warning = UTF8_WARN_FFFF;
455 	goto malformed;
456     }
457 
458     return uv;
459 
460 malformed:
461 
462     if (flags & UTF8_CHECK_ONLY) {
463 	if (retlen)
464 	    *retlen = -1;
465 	return 0;
466     }
467 
468     if (dowarn) {
469 	SV* sv = sv_2mortal(newSVpv("Malformed UTF-8 character ", 0));
470 
471 	switch (warning) {
472 	case 0: /* Intentionally empty. */ break;
473 	case UTF8_WARN_EMPTY:
474 	    Perl_sv_catpvf(aTHX_ sv, "(empty string)");
475 	    break;
476 	case UTF8_WARN_CONTINUATION:
477 	    Perl_sv_catpvf(aTHX_ sv, "(unexpected continuation byte 0x%02"UVxf", with no preceding start byte)", uv);
478 	    break;
479 	case UTF8_WARN_NON_CONTINUATION:
480 	    if (s == s0)
481 	        Perl_sv_catpvf(aTHX_ sv, "(unexpected non-continuation byte 0x%02"UVxf", immediately after start byte 0x%02"UVxf")",
482                            (UV)s[1], startbyte);
483 	    else
484 	        Perl_sv_catpvf(aTHX_ sv, "(unexpected non-continuation byte 0x%02"UVxf", %d byte%s after start byte 0x%02"UVxf", expected %d bytes)",
485                            (UV)s[1], s - s0, s - s0 > 1 ? "s" : "", startbyte, expectlen);
486 
487 	    break;
488 	case UTF8_WARN_FE_FF:
489 	    Perl_sv_catpvf(aTHX_ sv, "(byte 0x%02"UVxf")", uv);
490 	    break;
491 	case UTF8_WARN_SHORT:
492 	    Perl_sv_catpvf(aTHX_ sv, "(%d byte%s, need %d, after start byte 0x%02"UVxf")",
493                            curlen, curlen == 1 ? "" : "s", expectlen, startbyte);
494 	    expectlen = curlen;		/* distance for caller to skip */
495 	    break;
496 	case UTF8_WARN_OVERFLOW:
497 	    Perl_sv_catpvf(aTHX_ sv, "(overflow at 0x%"UVxf", byte 0x%02x, after start byte 0x%02"UVxf")",
498                            ouv, *s, startbyte);
499 	    break;
500 	case UTF8_WARN_SURROGATE:
501 	    Perl_sv_catpvf(aTHX_ sv, "(UTF-16 surrogate 0x%04"UVxf")", uv);
502 	    break;
503 	case UTF8_WARN_LONG:
504 	    Perl_sv_catpvf(aTHX_ sv, "(%d byte%s, need %d, after start byte 0x%02"UVxf")",
505 			   expectlen, expectlen == 1 ? "": "s", UNISKIP(uv), startbyte);
506 	    break;
507 	case UTF8_WARN_FFFF:
508 	    Perl_sv_catpvf(aTHX_ sv, "(character 0x%04"UVxf")", uv);
509 	    break;
510 	default:
511 	    Perl_sv_catpvf(aTHX_ sv, "(unknown reason)");
512 	    break;
513 	}
514 
515 	if (warning) {
516 	    char *s = SvPVX(sv);
517 
518 	    if (PL_op)
519 		Perl_warner(aTHX_ packWARN(WARN_UTF8),
520 			    "%s in %s", s,  OP_DESC(PL_op));
521 	    else
522 		Perl_warner(aTHX_ packWARN(WARN_UTF8), "%s", s);
523 	}
524     }
525 
526     if (retlen)
527 	*retlen = expectlen ? expectlen : len;
528 
529     return 0;
530 }
531 
532 /*
533 =for apidoc A|UV|utf8_to_uvchr|U8 *s|STRLEN *retlen
534 
535 Returns the native character value of the first character in the string C<s>
536 which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
537 length, in bytes, of that character.
538 
539 If C<s> does not point to a well-formed UTF-8 character, zero is
540 returned and retlen is set, if possible, to -1.
541 
542 =cut
543 */
544 
545 UV
546 Perl_utf8_to_uvchr(pTHX_ U8 *s, STRLEN *retlen)
547 {
548     return Perl_utf8n_to_uvchr(aTHX_ s, UTF8_MAXLEN, retlen,
549 			       ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
550 }
551 
552 /*
553 =for apidoc A|UV|utf8_to_uvuni|U8 *s|STRLEN *retlen
554 
555 Returns the Unicode code point of the first character in the string C<s>
556 which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
557 length, in bytes, of that character.
558 
559 This function should only be used when returned UV is considered
560 an index into the Unicode semantic tables (e.g. swashes).
561 
562 If C<s> does not point to a well-formed UTF-8 character, zero is
563 returned and retlen is set, if possible, to -1.
564 
565 =cut
566 */
567 
568 UV
569 Perl_utf8_to_uvuni(pTHX_ U8 *s, STRLEN *retlen)
570 {
571     /* Call the low level routine asking for checks */
572     return Perl_utf8n_to_uvuni(aTHX_ s, UTF8_MAXLEN, retlen,
573 			       ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
574 }
575 
576 /*
577 =for apidoc A|STRLEN|utf8_length|U8 *s|U8 *e
578 
579 Return the length of the UTF-8 char encoded string C<s> in characters.
580 Stops at C<e> (inclusive).  If C<e E<lt> s> or if the scan would end
581 up past C<e>, croaks.
582 
583 =cut
584 */
585 
586 STRLEN
587 Perl_utf8_length(pTHX_ U8 *s, U8 *e)
588 {
589     STRLEN len = 0;
590 
591     /* Note: cannot use UTF8_IS_...() too eagerly here since e.g.
592      * the bitops (especially ~) can create illegal UTF-8.
593      * In other words: in Perl UTF-8 is not just for Unicode. */
594 
595     if (e < s) {
596         if (ckWARN_d(WARN_UTF8)) {
597 	    if (PL_op)
598 	        Perl_warner(aTHX_ packWARN(WARN_UTF8),
599 			    "%s in %s", unees, OP_DESC(PL_op));
600 	    else
601 	        Perl_warner(aTHX_ packWARN(WARN_UTF8), unees);
602 	}
603 	return 0;
604     }
605     while (s < e) {
606 	U8 t = UTF8SKIP(s);
607 
608 	if (e - s < t) {
609 	    if (ckWARN_d(WARN_UTF8)) {
610 	        if (PL_op)
611 		    Perl_warner(aTHX_ packWARN(WARN_UTF8),
612 				unees, OP_DESC(PL_op));
613 		else
614 		    Perl_warner(aTHX_ packWARN(WARN_UTF8), unees);
615 	    }
616 	    return len;
617 	}
618 	s += t;
619 	len++;
620     }
621 
622     return len;
623 }
624 
625 /*
626 =for apidoc A|IV|utf8_distance|U8 *a|U8 *b
627 
628 Returns the number of UTF-8 characters between the UTF-8 pointers C<a>
629 and C<b>.
630 
631 WARNING: use only if you *know* that the pointers point inside the
632 same UTF-8 buffer.
633 
634 =cut
635 */
636 
637 IV
638 Perl_utf8_distance(pTHX_ U8 *a, U8 *b)
639 {
640     IV off = 0;
641 
642     /* Note: cannot use UTF8_IS_...() too eagerly here since  e.g.
643      * the bitops (especially ~) can create illegal UTF-8.
644      * In other words: in Perl UTF-8 is not just for Unicode. */
645 
646     if (a < b) {
647 	while (a < b) {
648 	    U8 c = UTF8SKIP(a);
649 
650 	    if (b - a < c) {
651 	        if (ckWARN_d(WARN_UTF8)) {
652 		    if (PL_op)
653 		        Perl_warner(aTHX_ packWARN(WARN_UTF8),
654 				    "%s in %s", unees, OP_DESC(PL_op));
655 		    else
656 		        Perl_warner(aTHX_ packWARN(WARN_UTF8), unees);
657 		}
658 		return off;
659 	    }
660 	    a += c;
661 	    off--;
662 	}
663     }
664     else {
665 	while (b < a) {
666 	    U8 c = UTF8SKIP(b);
667 
668 	    if (a - b < c) {
669 	        if (ckWARN_d(WARN_UTF8)) {
670 		    if (PL_op)
671 		        Perl_warner(aTHX_ packWARN(WARN_UTF8),
672 				    "%s in %s", unees, OP_DESC(PL_op));
673 		    else
674 		        Perl_warner(aTHX_ packWARN(WARN_UTF8), unees);
675 		}
676 		return off;
677 	    }
678 	    b += c;
679 	    off++;
680 	}
681     }
682 
683     return off;
684 }
685 
686 /*
687 =for apidoc A|U8 *|utf8_hop|U8 *s|I32 off
688 
689 Return the UTF-8 pointer C<s> displaced by C<off> characters, either
690 forward or backward.
691 
692 WARNING: do not use the following unless you *know* C<off> is within
693 the UTF-8 data pointed to by C<s> *and* that on entry C<s> is aligned
694 on the first byte of character or just after the last byte of a character.
695 
696 =cut
697 */
698 
699 U8 *
700 Perl_utf8_hop(pTHX_ U8 *s, I32 off)
701 {
702     /* Note: cannot use UTF8_IS_...() too eagerly here since e.g
703      * the bitops (especially ~) can create illegal UTF-8.
704      * In other words: in Perl UTF-8 is not just for Unicode. */
705 
706     if (off >= 0) {
707 	while (off--)
708 	    s += UTF8SKIP(s);
709     }
710     else {
711 	while (off++) {
712 	    s--;
713 	    while (UTF8_IS_CONTINUATION(*s))
714 		s--;
715 	}
716     }
717     return s;
718 }
719 
720 /*
721 =for apidoc A|U8 *|utf8_to_bytes|U8 *s|STRLEN *len
722 
723 Converts a string C<s> of length C<len> from UTF-8 into byte encoding.
724 Unlike C<bytes_to_utf8>, this over-writes the original string, and
725 updates len to contain the new length.
726 Returns zero on failure, setting C<len> to -1.
727 
728 =cut
729 */
730 
731 U8 *
732 Perl_utf8_to_bytes(pTHX_ U8 *s, STRLEN *len)
733 {
734     U8 *send;
735     U8 *d;
736     U8 *save = s;
737 
738     /* ensure valid UTF-8 and chars < 256 before updating string */
739     for (send = s + *len; s < send; ) {
740         U8 c = *s++;
741 
742         if (!UTF8_IS_INVARIANT(c) &&
743             (!UTF8_IS_DOWNGRADEABLE_START(c) || (s >= send)
744 	     || !(c = *s++) || !UTF8_IS_CONTINUATION(c))) {
745             *len = -1;
746             return 0;
747         }
748     }
749 
750     d = s = save;
751     while (s < send) {
752         STRLEN ulen;
753         *d++ = (U8)utf8_to_uvchr(s, &ulen);
754         s += ulen;
755     }
756     *d = '\0';
757     *len = d - save;
758     return save;
759 }
760 
761 /*
762 =for apidoc A|U8 *|bytes_from_utf8|U8 *s|STRLEN *len|bool *is_utf8
763 
764 Converts a string C<s> of length C<len> from UTF-8 into byte encoding.
765 Unlike <utf8_to_bytes> but like C<bytes_to_utf8>, returns a pointer to
766 the newly-created string, and updates C<len> to contain the new
767 length.  Returns the original string if no conversion occurs, C<len>
768 is unchanged. Do nothing if C<is_utf8> points to 0. Sets C<is_utf8> to
769 0 if C<s> is converted or contains all 7bit characters.
770 
771 =cut
772 */
773 
774 U8 *
775 Perl_bytes_from_utf8(pTHX_ U8 *s, STRLEN *len, bool *is_utf8)
776 {
777     U8 *d;
778     U8 *start = s;
779     U8 *send;
780     I32 count = 0;
781 
782     if (!*is_utf8)
783 	return start;
784 
785     /* ensure valid UTF-8 and chars < 256 before converting string */
786     for (send = s + *len; s < send;) {
787 	U8 c = *s++;
788 	if (!UTF8_IS_INVARIANT(c)) {
789 	    if (UTF8_IS_DOWNGRADEABLE_START(c) && s < send &&
790                 (c = *s++) && UTF8_IS_CONTINUATION(c))
791 		count++;
792 	    else
793 		return start;
794 	}
795     }
796 
797     *is_utf8 = 0;
798 
799     Newz(801, d, (*len) - count + 1, U8);
800     s = start; start = d;
801     while (s < send) {
802 	U8 c = *s++;
803 	if (!UTF8_IS_INVARIANT(c)) {
804 	    /* Then it is two-byte encoded */
805 	    c = UTF8_ACCUMULATE(NATIVE_TO_UTF(c), *s++);
806 	    c = ASCII_TO_NATIVE(c);
807 	}
808 	*d++ = c;
809     }
810     *d = '\0';
811     *len = d - start;
812     return start;
813 }
814 
815 /*
816 =for apidoc A|U8 *|bytes_to_utf8|U8 *s|STRLEN *len
817 
818 Converts a string C<s> of length C<len> from ASCII into UTF-8 encoding.
819 Returns a pointer to the newly-created string, and sets C<len> to
820 reflect the new length.
821 
822 If you want to convert to UTF-8 from other encodings than ASCII,
823 see sv_recode_to_utf8().
824 
825 =cut
826 */
827 
828 U8*
829 Perl_bytes_to_utf8(pTHX_ U8 *s, STRLEN *len)
830 {
831     U8 *send;
832     U8 *d;
833     U8 *dst;
834     send = s + (*len);
835 
836     Newz(801, d, (*len) * 2 + 1, U8);
837     dst = d;
838 
839     while (s < send) {
840         UV uv = NATIVE_TO_ASCII(*s++);
841         if (UNI_IS_INVARIANT(uv))
842             *d++ = (U8)UTF_TO_NATIVE(uv);
843         else {
844             *d++ = (U8)UTF8_EIGHT_BIT_HI(uv);
845             *d++ = (U8)UTF8_EIGHT_BIT_LO(uv);
846         }
847     }
848     *d = '\0';
849     *len = d-dst;
850     return dst;
851 }
852 
853 /*
854  * Convert native (big-endian) or reversed (little-endian) UTF-16 to UTF-8.
855  *
856  * Destination must be pre-extended to 3/2 source.  Do not use in-place.
857  * We optimize for native, for obvious reasons. */
858 
859 U8*
860 Perl_utf16_to_utf8(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
861 {
862     U8* pend;
863     U8* dstart = d;
864 
865     if (bytelen & 1)
866 	Perl_croak(aTHX_ "panic: utf16_to_utf8: odd bytelen");
867 
868     pend = p + bytelen;
869 
870     while (p < pend) {
871 	UV uv = (p[0] << 8) + p[1]; /* UTF-16BE */
872 	p += 2;
873 	if (uv < 0x80) {
874 	    *d++ = (U8)uv;
875 	    continue;
876 	}
877 	if (uv < 0x800) {
878 	    *d++ = (U8)(( uv >>  6)         | 0xc0);
879 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
880 	    continue;
881 	}
882 	if (uv >= 0xd800 && uv < 0xdbff) {	/* surrogates */
883 	    UV low = (p[0] << 8) + p[1];
884 	    p += 2;
885 	    if (low < 0xdc00 || low >= 0xdfff)
886 		Perl_croak(aTHX_ "Malformed UTF-16 surrogate");
887 	    uv = ((uv - 0xd800) << 10) + (low - 0xdc00) + 0x10000;
888 	}
889 	if (uv < 0x10000) {
890 	    *d++ = (U8)(( uv >> 12)         | 0xe0);
891 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
892 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
893 	    continue;
894 	}
895 	else {
896 	    *d++ = (U8)(( uv >> 18)         | 0xf0);
897 	    *d++ = (U8)(((uv >> 12) & 0x3f) | 0x80);
898 	    *d++ = (U8)(((uv >>  6) & 0x3f) | 0x80);
899 	    *d++ = (U8)(( uv        & 0x3f) | 0x80);
900 	    continue;
901 	}
902     }
903     *newlen = d - dstart;
904     return d;
905 }
906 
907 /* Note: this one is slightly destructive of the source. */
908 
909 U8*
910 Perl_utf16_to_utf8_reversed(pTHX_ U8* p, U8* d, I32 bytelen, I32 *newlen)
911 {
912     U8* s = (U8*)p;
913     U8* send = s + bytelen;
914     while (s < send) {
915 	U8 tmp = s[0];
916 	s[0] = s[1];
917 	s[1] = tmp;
918 	s += 2;
919     }
920     return utf16_to_utf8(p, d, bytelen, newlen);
921 }
922 
923 /* for now these are all defined (inefficiently) in terms of the utf8 versions */
924 
925 bool
926 Perl_is_uni_alnum(pTHX_ UV c)
927 {
928     U8 tmpbuf[UTF8_MAXLEN+1];
929     uvchr_to_utf8(tmpbuf, c);
930     return is_utf8_alnum(tmpbuf);
931 }
932 
933 bool
934 Perl_is_uni_alnumc(pTHX_ UV c)
935 {
936     U8 tmpbuf[UTF8_MAXLEN+1];
937     uvchr_to_utf8(tmpbuf, c);
938     return is_utf8_alnumc(tmpbuf);
939 }
940 
941 bool
942 Perl_is_uni_idfirst(pTHX_ UV c)
943 {
944     U8 tmpbuf[UTF8_MAXLEN+1];
945     uvchr_to_utf8(tmpbuf, c);
946     return is_utf8_idfirst(tmpbuf);
947 }
948 
949 bool
950 Perl_is_uni_alpha(pTHX_ UV c)
951 {
952     U8 tmpbuf[UTF8_MAXLEN+1];
953     uvchr_to_utf8(tmpbuf, c);
954     return is_utf8_alpha(tmpbuf);
955 }
956 
957 bool
958 Perl_is_uni_ascii(pTHX_ UV c)
959 {
960     U8 tmpbuf[UTF8_MAXLEN+1];
961     uvchr_to_utf8(tmpbuf, c);
962     return is_utf8_ascii(tmpbuf);
963 }
964 
965 bool
966 Perl_is_uni_space(pTHX_ UV c)
967 {
968     U8 tmpbuf[UTF8_MAXLEN+1];
969     uvchr_to_utf8(tmpbuf, c);
970     return is_utf8_space(tmpbuf);
971 }
972 
973 bool
974 Perl_is_uni_digit(pTHX_ UV c)
975 {
976     U8 tmpbuf[UTF8_MAXLEN+1];
977     uvchr_to_utf8(tmpbuf, c);
978     return is_utf8_digit(tmpbuf);
979 }
980 
981 bool
982 Perl_is_uni_upper(pTHX_ UV c)
983 {
984     U8 tmpbuf[UTF8_MAXLEN+1];
985     uvchr_to_utf8(tmpbuf, c);
986     return is_utf8_upper(tmpbuf);
987 }
988 
989 bool
990 Perl_is_uni_lower(pTHX_ UV c)
991 {
992     U8 tmpbuf[UTF8_MAXLEN+1];
993     uvchr_to_utf8(tmpbuf, c);
994     return is_utf8_lower(tmpbuf);
995 }
996 
997 bool
998 Perl_is_uni_cntrl(pTHX_ UV c)
999 {
1000     U8 tmpbuf[UTF8_MAXLEN+1];
1001     uvchr_to_utf8(tmpbuf, c);
1002     return is_utf8_cntrl(tmpbuf);
1003 }
1004 
1005 bool
1006 Perl_is_uni_graph(pTHX_ UV c)
1007 {
1008     U8 tmpbuf[UTF8_MAXLEN+1];
1009     uvchr_to_utf8(tmpbuf, c);
1010     return is_utf8_graph(tmpbuf);
1011 }
1012 
1013 bool
1014 Perl_is_uni_print(pTHX_ UV c)
1015 {
1016     U8 tmpbuf[UTF8_MAXLEN+1];
1017     uvchr_to_utf8(tmpbuf, c);
1018     return is_utf8_print(tmpbuf);
1019 }
1020 
1021 bool
1022 Perl_is_uni_punct(pTHX_ UV c)
1023 {
1024     U8 tmpbuf[UTF8_MAXLEN+1];
1025     uvchr_to_utf8(tmpbuf, c);
1026     return is_utf8_punct(tmpbuf);
1027 }
1028 
1029 bool
1030 Perl_is_uni_xdigit(pTHX_ UV c)
1031 {
1032     U8 tmpbuf[UTF8_MAXLEN_UCLC+1];
1033     uvchr_to_utf8(tmpbuf, c);
1034     return is_utf8_xdigit(tmpbuf);
1035 }
1036 
1037 UV
1038 Perl_to_uni_upper(pTHX_ UV c, U8* p, STRLEN *lenp)
1039 {
1040     uvchr_to_utf8(p, c);
1041     return to_utf8_upper(p, p, lenp);
1042 }
1043 
1044 UV
1045 Perl_to_uni_title(pTHX_ UV c, U8* p, STRLEN *lenp)
1046 {
1047     uvchr_to_utf8(p, c);
1048     return to_utf8_title(p, p, lenp);
1049 }
1050 
1051 UV
1052 Perl_to_uni_lower(pTHX_ UV c, U8* p, STRLEN *lenp)
1053 {
1054     uvchr_to_utf8(p, c);
1055     return to_utf8_lower(p, p, lenp);
1056 }
1057 
1058 UV
1059 Perl_to_uni_fold(pTHX_ UV c, U8* p, STRLEN *lenp)
1060 {
1061     uvchr_to_utf8(p, c);
1062     return to_utf8_fold(p, p, lenp);
1063 }
1064 
1065 /* for now these all assume no locale info available for Unicode > 255 */
1066 
1067 bool
1068 Perl_is_uni_alnum_lc(pTHX_ UV c)
1069 {
1070     return is_uni_alnum(c);	/* XXX no locale support yet */
1071 }
1072 
1073 bool
1074 Perl_is_uni_alnumc_lc(pTHX_ UV c)
1075 {
1076     return is_uni_alnumc(c);	/* XXX no locale support yet */
1077 }
1078 
1079 bool
1080 Perl_is_uni_idfirst_lc(pTHX_ UV c)
1081 {
1082     return is_uni_idfirst(c);	/* XXX no locale support yet */
1083 }
1084 
1085 bool
1086 Perl_is_uni_alpha_lc(pTHX_ UV c)
1087 {
1088     return is_uni_alpha(c);	/* XXX no locale support yet */
1089 }
1090 
1091 bool
1092 Perl_is_uni_ascii_lc(pTHX_ UV c)
1093 {
1094     return is_uni_ascii(c);	/* XXX no locale support yet */
1095 }
1096 
1097 bool
1098 Perl_is_uni_space_lc(pTHX_ UV c)
1099 {
1100     return is_uni_space(c);	/* XXX no locale support yet */
1101 }
1102 
1103 bool
1104 Perl_is_uni_digit_lc(pTHX_ UV c)
1105 {
1106     return is_uni_digit(c);	/* XXX no locale support yet */
1107 }
1108 
1109 bool
1110 Perl_is_uni_upper_lc(pTHX_ UV c)
1111 {
1112     return is_uni_upper(c);	/* XXX no locale support yet */
1113 }
1114 
1115 bool
1116 Perl_is_uni_lower_lc(pTHX_ UV c)
1117 {
1118     return is_uni_lower(c);	/* XXX no locale support yet */
1119 }
1120 
1121 bool
1122 Perl_is_uni_cntrl_lc(pTHX_ UV c)
1123 {
1124     return is_uni_cntrl(c);	/* XXX no locale support yet */
1125 }
1126 
1127 bool
1128 Perl_is_uni_graph_lc(pTHX_ UV c)
1129 {
1130     return is_uni_graph(c);	/* XXX no locale support yet */
1131 }
1132 
1133 bool
1134 Perl_is_uni_print_lc(pTHX_ UV c)
1135 {
1136     return is_uni_print(c);	/* XXX no locale support yet */
1137 }
1138 
1139 bool
1140 Perl_is_uni_punct_lc(pTHX_ UV c)
1141 {
1142     return is_uni_punct(c);	/* XXX no locale support yet */
1143 }
1144 
1145 bool
1146 Perl_is_uni_xdigit_lc(pTHX_ UV c)
1147 {
1148     return is_uni_xdigit(c);	/* XXX no locale support yet */
1149 }
1150 
1151 U32
1152 Perl_to_uni_upper_lc(pTHX_ U32 c)
1153 {
1154     /* XXX returns only the first character -- do not use XXX */
1155     /* XXX no locale support yet */
1156     STRLEN len;
1157     U8 tmpbuf[UTF8_MAXLEN_UCLC+1];
1158     return (U32)to_uni_upper(c, tmpbuf, &len);
1159 }
1160 
1161 U32
1162 Perl_to_uni_title_lc(pTHX_ U32 c)
1163 {
1164     /* XXX returns only the first character XXX -- do not use XXX */
1165     /* XXX no locale support yet */
1166     STRLEN len;
1167     U8 tmpbuf[UTF8_MAXLEN_UCLC+1];
1168     return (U32)to_uni_title(c, tmpbuf, &len);
1169 }
1170 
1171 U32
1172 Perl_to_uni_lower_lc(pTHX_ U32 c)
1173 {
1174     /* XXX returns only the first character -- do not use XXX */
1175     /* XXX no locale support yet */
1176     STRLEN len;
1177     U8 tmpbuf[UTF8_MAXLEN_UCLC+1];
1178     return (U32)to_uni_lower(c, tmpbuf, &len);
1179 }
1180 
1181 bool
1182 Perl_is_utf8_alnum(pTHX_ U8 *p)
1183 {
1184     if (!is_utf8_char(p))
1185 	return FALSE;
1186     if (!PL_utf8_alnum)
1187 	/* NOTE: "IsWord", not "IsAlnum", since Alnum is a true
1188 	 * descendant of isalnum(3), in other words, it doesn't
1189 	 * contain the '_'. --jhi */
1190 	PL_utf8_alnum = swash_init("utf8", "IsWord", &PL_sv_undef, 0, 0);
1191     return swash_fetch(PL_utf8_alnum, p, TRUE) != 0;
1192 /*    return *p == '_' || is_utf8_alpha(p) || is_utf8_digit(p); */
1193 #ifdef SURPRISINGLY_SLOWER  /* probably because alpha is usually true */
1194     if (!PL_utf8_alnum)
1195 	PL_utf8_alnum = swash_init("utf8", "",
1196 	    sv_2mortal(newSVpv("+utf8::IsAlpha\n+utf8::IsDigit\n005F\n",0)), 0, 0);
1197     return swash_fetch(PL_utf8_alnum, p, TRUE) != 0;
1198 #endif
1199 }
1200 
1201 bool
1202 Perl_is_utf8_alnumc(pTHX_ U8 *p)
1203 {
1204     if (!is_utf8_char(p))
1205 	return FALSE;
1206     if (!PL_utf8_alnum)
1207 	PL_utf8_alnum = swash_init("utf8", "IsAlnumC", &PL_sv_undef, 0, 0);
1208     return swash_fetch(PL_utf8_alnum, p, TRUE) != 0;
1209 /*    return is_utf8_alpha(p) || is_utf8_digit(p); */
1210 #ifdef SURPRISINGLY_SLOWER  /* probably because alpha is usually true */
1211     if (!PL_utf8_alnum)
1212 	PL_utf8_alnum = swash_init("utf8", "",
1213 	    sv_2mortal(newSVpv("+utf8::IsAlpha\n+utf8::IsDigit\n005F\n",0)), 0, 0);
1214     return swash_fetch(PL_utf8_alnum, p, TRUE) != 0;
1215 #endif
1216 }
1217 
1218 bool
1219 Perl_is_utf8_idfirst(pTHX_ U8 *p) /* The naming is historical. */
1220 {
1221     if (*p == '_')
1222 	return TRUE;
1223     if (!is_utf8_char(p))
1224 	return FALSE;
1225     if (!PL_utf8_idstart) /* is_utf8_idstart would be more logical. */
1226 	PL_utf8_idstart = swash_init("utf8", "IdStart", &PL_sv_undef, 0, 0);
1227     return swash_fetch(PL_utf8_idstart, p, TRUE) != 0;
1228 }
1229 
1230 bool
1231 Perl_is_utf8_idcont(pTHX_ U8 *p)
1232 {
1233     if (*p == '_')
1234 	return TRUE;
1235     if (!is_utf8_char(p))
1236 	return FALSE;
1237     if (!PL_utf8_idcont)
1238 	PL_utf8_idcont = swash_init("utf8", "IdContinue", &PL_sv_undef, 0, 0);
1239     return swash_fetch(PL_utf8_idcont, p, TRUE) != 0;
1240 }
1241 
1242 bool
1243 Perl_is_utf8_alpha(pTHX_ U8 *p)
1244 {
1245     if (!is_utf8_char(p))
1246 	return FALSE;
1247     if (!PL_utf8_alpha)
1248 	PL_utf8_alpha = swash_init("utf8", "IsAlpha", &PL_sv_undef, 0, 0);
1249     return swash_fetch(PL_utf8_alpha, p, TRUE) != 0;
1250 }
1251 
1252 bool
1253 Perl_is_utf8_ascii(pTHX_ U8 *p)
1254 {
1255     if (!is_utf8_char(p))
1256 	return FALSE;
1257     if (!PL_utf8_ascii)
1258 	PL_utf8_ascii = swash_init("utf8", "IsAscii", &PL_sv_undef, 0, 0);
1259     return swash_fetch(PL_utf8_ascii, p, TRUE) != 0;
1260 }
1261 
1262 bool
1263 Perl_is_utf8_space(pTHX_ U8 *p)
1264 {
1265     if (!is_utf8_char(p))
1266 	return FALSE;
1267     if (!PL_utf8_space)
1268 	PL_utf8_space = swash_init("utf8", "IsSpacePerl", &PL_sv_undef, 0, 0);
1269     return swash_fetch(PL_utf8_space, p, TRUE) != 0;
1270 }
1271 
1272 bool
1273 Perl_is_utf8_digit(pTHX_ U8 *p)
1274 {
1275     if (!is_utf8_char(p))
1276 	return FALSE;
1277     if (!PL_utf8_digit)
1278 	PL_utf8_digit = swash_init("utf8", "IsDigit", &PL_sv_undef, 0, 0);
1279     return swash_fetch(PL_utf8_digit, p, TRUE) != 0;
1280 }
1281 
1282 bool
1283 Perl_is_utf8_upper(pTHX_ U8 *p)
1284 {
1285     if (!is_utf8_char(p))
1286 	return FALSE;
1287     if (!PL_utf8_upper)
1288 	PL_utf8_upper = swash_init("utf8", "IsUppercase", &PL_sv_undef, 0, 0);
1289     return swash_fetch(PL_utf8_upper, p, TRUE) != 0;
1290 }
1291 
1292 bool
1293 Perl_is_utf8_lower(pTHX_ U8 *p)
1294 {
1295     if (!is_utf8_char(p))
1296 	return FALSE;
1297     if (!PL_utf8_lower)
1298 	PL_utf8_lower = swash_init("utf8", "IsLowercase", &PL_sv_undef, 0, 0);
1299     return swash_fetch(PL_utf8_lower, p, TRUE) != 0;
1300 }
1301 
1302 bool
1303 Perl_is_utf8_cntrl(pTHX_ U8 *p)
1304 {
1305     if (!is_utf8_char(p))
1306 	return FALSE;
1307     if (!PL_utf8_cntrl)
1308 	PL_utf8_cntrl = swash_init("utf8", "IsCntrl", &PL_sv_undef, 0, 0);
1309     return swash_fetch(PL_utf8_cntrl, p, TRUE) != 0;
1310 }
1311 
1312 bool
1313 Perl_is_utf8_graph(pTHX_ U8 *p)
1314 {
1315     if (!is_utf8_char(p))
1316 	return FALSE;
1317     if (!PL_utf8_graph)
1318 	PL_utf8_graph = swash_init("utf8", "IsGraph", &PL_sv_undef, 0, 0);
1319     return swash_fetch(PL_utf8_graph, p, TRUE) != 0;
1320 }
1321 
1322 bool
1323 Perl_is_utf8_print(pTHX_ U8 *p)
1324 {
1325     if (!is_utf8_char(p))
1326 	return FALSE;
1327     if (!PL_utf8_print)
1328 	PL_utf8_print = swash_init("utf8", "IsPrint", &PL_sv_undef, 0, 0);
1329     return swash_fetch(PL_utf8_print, p, TRUE) != 0;
1330 }
1331 
1332 bool
1333 Perl_is_utf8_punct(pTHX_ U8 *p)
1334 {
1335     if (!is_utf8_char(p))
1336 	return FALSE;
1337     if (!PL_utf8_punct)
1338 	PL_utf8_punct = swash_init("utf8", "IsPunct", &PL_sv_undef, 0, 0);
1339     return swash_fetch(PL_utf8_punct, p, TRUE) != 0;
1340 }
1341 
1342 bool
1343 Perl_is_utf8_xdigit(pTHX_ U8 *p)
1344 {
1345     if (!is_utf8_char(p))
1346 	return FALSE;
1347     if (!PL_utf8_xdigit)
1348 	PL_utf8_xdigit = swash_init("utf8", "IsXDigit", &PL_sv_undef, 0, 0);
1349     return swash_fetch(PL_utf8_xdigit, p, TRUE) != 0;
1350 }
1351 
1352 bool
1353 Perl_is_utf8_mark(pTHX_ U8 *p)
1354 {
1355     if (!is_utf8_char(p))
1356 	return FALSE;
1357     if (!PL_utf8_mark)
1358 	PL_utf8_mark = swash_init("utf8", "IsM", &PL_sv_undef, 0, 0);
1359     return swash_fetch(PL_utf8_mark, p, TRUE) != 0;
1360 }
1361 
1362 /*
1363 =for apidoc A|UV|to_utf8_case|U8 *p|U8* ustrp|STRLEN *lenp|SV **swash|char *normal|char *special
1364 
1365 The "p" contains the pointer to the UTF-8 string encoding
1366 the character that is being converted.
1367 
1368 The "ustrp" is a pointer to the character buffer to put the
1369 conversion result to.  The "lenp" is a pointer to the length
1370 of the result.
1371 
1372 The "swashp" is a pointer to the swash to use.
1373 
1374 Both the special and normal mappings are stored lib/unicore/To/Foo.pl,
1375 and loaded by SWASHGET, using lib/utf8_heavy.pl.  The special (usually,
1376 but not always, a multicharacter mapping), is tried first.
1377 
1378 The "special" is a string like "utf8::ToSpecLower", which means the
1379 hash %utf8::ToSpecLower.  The access to the hash is through
1380 Perl_to_utf8_case().
1381 
1382 The "normal" is a string like "ToLower" which means the swash
1383 %utf8::ToLower.
1384 
1385 =cut */
1386 
1387 UV
1388 Perl_to_utf8_case(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp, SV **swashp, char *normal, char *special)
1389 {
1390     UV uv0, uv1;
1391     U8 tmpbuf[UTF8_MAXLEN_FOLD+1];
1392     STRLEN len = 0;
1393 
1394     uv0 = utf8_to_uvchr(p, 0);
1395     /* The NATIVE_TO_UNI() and UNI_TO_NATIVE() mappings
1396      * are necessary in EBCDIC, they are redundant no-ops
1397      * in ASCII-ish platforms, and hopefully optimized away. */
1398     uv1 = NATIVE_TO_UNI(uv0);
1399     uvuni_to_utf8(tmpbuf, uv1);
1400 
1401     if (!*swashp) /* load on-demand */
1402          *swashp = swash_init("utf8", normal, &PL_sv_undef, 4, 0);
1403 
1404     if (special) {
1405          /* It might be "special" (sometimes, but not always,
1406 	  * a multicharacter mapping) */
1407 	 HV *hv;
1408 	 SV *keysv;
1409 	 HE *he;
1410 	 SV *val;
1411 
1412 	 if ((hv    = get_hv(special, FALSE)) &&
1413 	     (keysv = sv_2mortal(Perl_newSVpvf(aTHX_ "%04"UVXf, uv1))) &&
1414 	     (he    = hv_fetch_ent(hv, keysv, FALSE, 0)) &&
1415 	     (val   = HeVAL(he))) {
1416 	     char *s;
1417 
1418 	      s = SvPV(val, len);
1419 	      if (len == 1)
1420 		   len = uvuni_to_utf8(ustrp, NATIVE_TO_UNI(*(U8*)s)) - ustrp;
1421 	      else {
1422 #ifdef EBCDIC
1423 		   /* If we have EBCDIC we need to remap the characters
1424 		    * since any characters in the low 256 are Unicode
1425 		    * code points, not EBCDIC. */
1426 		   U8 *t = (U8*)s, *tend = t + len, *d;
1427 
1428 		   d = tmpbuf;
1429 		   if (SvUTF8(val)) {
1430 			STRLEN tlen = 0;
1431 
1432 			while (t < tend) {
1433 			     UV c = utf8_to_uvchr(t, &tlen);
1434 			     if (tlen > 0) {
1435 				  d = uvchr_to_utf8(d, UNI_TO_NATIVE(c));
1436 				  t += tlen;
1437 			     }
1438 			     else
1439 				  break;
1440 			}
1441 		   }
1442 		   else {
1443 			while (t < tend) {
1444 			     d = uvchr_to_utf8(d, UNI_TO_NATIVE(*t));
1445 			     t++;
1446 			}
1447 		   }
1448 		   len = d - tmpbuf;
1449 		   Copy(tmpbuf, ustrp, len, U8);
1450 #else
1451 		   Copy(s, ustrp, len, U8);
1452 #endif
1453 	      }
1454 	 }
1455     }
1456 
1457     if (!len && *swashp) {
1458 	 UV uv2 = swash_fetch(*swashp, tmpbuf, TRUE);
1459 
1460 	 if (uv2) {
1461 	      /* It was "normal" (a single character mapping). */
1462 	      UV uv3 = UNI_TO_NATIVE(uv2);
1463 
1464 	      len = uvchr_to_utf8(ustrp, uv3) - ustrp;
1465 	 }
1466     }
1467 
1468     if (!len) /* Neither: just copy. */
1469 	 len = uvchr_to_utf8(ustrp, uv0) - ustrp;
1470 
1471     if (lenp)
1472 	 *lenp = len;
1473 
1474     return len ? utf8_to_uvchr(ustrp, 0) : 0;
1475 }
1476 
1477 /*
1478 =for apidoc A|UV|to_utf8_upper|U8 *p|U8 *ustrp|STRLEN *lenp
1479 
1480 Convert the UTF-8 encoded character at p to its uppercase version and
1481 store that in UTF-8 in ustrp and its length in bytes in lenp.  Note
1482 that the ustrp needs to be at least UTF8_MAXLEN_UCLC+1 bytes since the
1483 uppercase version may be longer than the original character (up to two
1484 characters).
1485 
1486 The first character of the uppercased version is returned
1487 (but note, as explained above, that there may be more.)
1488 
1489 =cut */
1490 
1491 UV
1492 Perl_to_utf8_upper(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
1493 {
1494     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
1495                              &PL_utf8_toupper, "ToUpper", "utf8::ToSpecUpper");
1496 }
1497 
1498 /*
1499 =for apidoc A|UV|to_utf8_title|U8 *p|U8 *ustrp|STRLEN *lenp
1500 
1501 Convert the UTF-8 encoded character at p to its titlecase version and
1502 store that in UTF-8 in ustrp and its length in bytes in lenp.  Note
1503 that the ustrp needs to be at least UTF8_MAXLEN_UCLC+1 bytes since the
1504 titlecase version may be longer than the original character (up to two
1505 characters).
1506 
1507 The first character of the titlecased version is returned
1508 (but note, as explained above, that there may be more.)
1509 
1510 =cut */
1511 
1512 UV
1513 Perl_to_utf8_title(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
1514 {
1515     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
1516                              &PL_utf8_totitle, "ToTitle", "utf8::ToSpecTitle");
1517 }
1518 
1519 /*
1520 =for apidoc A|UV|to_utf8_lower|U8 *p|U8 *ustrp|STRLEN *lenp
1521 
1522 Convert the UTF-8 encoded character at p to its lowercase version and
1523 store that in UTF-8 in ustrp and its length in bytes in lenp.  Note
1524 that the ustrp needs to be at least UTF8_MAXLEN_UCLC+1 bytes since the
1525 lowercase version may be longer than the original character (up to two
1526 characters).
1527 
1528 The first character of the lowercased version is returned
1529 (but note, as explained above, that there may be more.)
1530 
1531 =cut */
1532 
1533 UV
1534 Perl_to_utf8_lower(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
1535 {
1536     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
1537                              &PL_utf8_tolower, "ToLower", "utf8::ToSpecLower");
1538 }
1539 
1540 /*
1541 =for apidoc A|UV|to_utf8_fold|U8 *p|U8 *ustrp|STRLEN *lenp
1542 
1543 Convert the UTF-8 encoded character at p to its foldcase version and
1544 store that in UTF-8 in ustrp and its length in bytes in lenp.  Note
1545 that the ustrp needs to be at least UTF8_MAXLEN_FOLD+1 bytes since the
1546 foldcase version may be longer than the original character (up to
1547 three characters).
1548 
1549 The first character of the foldcased version is returned
1550 (but note, as explained above, that there may be more.)
1551 
1552 =cut */
1553 
1554 UV
1555 Perl_to_utf8_fold(pTHX_ U8 *p, U8* ustrp, STRLEN *lenp)
1556 {
1557     return Perl_to_utf8_case(aTHX_ p, ustrp, lenp,
1558                              &PL_utf8_tofold, "ToFold", "utf8::ToSpecFold");
1559 }
1560 
1561 /* a "swash" is a swatch hash */
1562 
1563 SV*
1564 Perl_swash_init(pTHX_ char* pkg, char* name, SV *listsv, I32 minbits, I32 none)
1565 {
1566     SV* retval;
1567     SV* tokenbufsv = sv_2mortal(NEWSV(0,0));
1568     dSP;
1569     HV *stash = gv_stashpvn(pkg, strlen(pkg), FALSE);
1570     SV* errsv_save;
1571 
1572     if (!gv_fetchmeth(stash, "SWASHNEW", 8, -1)) {	/* demand load utf8 */
1573 	ENTER;
1574 	errsv_save = newSVsv(ERRSV);
1575 	Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT, newSVpv(pkg,0), Nullsv);
1576 	if (!SvTRUE(ERRSV))
1577 	    sv_setsv(ERRSV, errsv_save);
1578 	SvREFCNT_dec(errsv_save);
1579 	LEAVE;
1580     }
1581     SPAGAIN;
1582     PUSHSTACKi(PERLSI_MAGIC);
1583     PUSHMARK(SP);
1584     EXTEND(SP,5);
1585     PUSHs(sv_2mortal(newSVpvn(pkg, strlen(pkg))));
1586     PUSHs(sv_2mortal(newSVpvn(name, strlen(name))));
1587     PUSHs(listsv);
1588     PUSHs(sv_2mortal(newSViv(minbits)));
1589     PUSHs(sv_2mortal(newSViv(none)));
1590     PUTBACK;
1591     ENTER;
1592     SAVEI32(PL_hints);
1593     PL_hints = 0;
1594     save_re_context();
1595     if (IN_PERL_COMPILETIME) {
1596 	/* XXX ought to be handled by lex_start */
1597 	SAVEI32(PL_in_my);
1598 	PL_in_my = 0;
1599 	sv_setpv(tokenbufsv, PL_tokenbuf);
1600     }
1601     errsv_save = newSVsv(ERRSV);
1602     if (call_method("SWASHNEW", G_SCALAR))
1603 	retval = newSVsv(*PL_stack_sp--);
1604     else
1605 	retval = &PL_sv_undef;
1606     if (!SvTRUE(ERRSV))
1607 	sv_setsv(ERRSV, errsv_save);
1608     SvREFCNT_dec(errsv_save);
1609     LEAVE;
1610     POPSTACK;
1611     if (IN_PERL_COMPILETIME) {
1612 	STRLEN len;
1613 	char* pv = SvPV(tokenbufsv, len);
1614 
1615 	Copy(pv, PL_tokenbuf, len+1, char);
1616 	PL_curcop->op_private = (U8)(PL_hints & HINT_PRIVATE_MASK);
1617     }
1618     if (!SvROK(retval) || SvTYPE(SvRV(retval)) != SVt_PVHV) {
1619         if (SvPOK(retval))
1620 	    Perl_croak(aTHX_ "Can't find Unicode property definition \"%"SVf"\"",
1621 		       retval);
1622 	Perl_croak(aTHX_ "SWASHNEW didn't return an HV ref");
1623     }
1624     return retval;
1625 }
1626 
1627 
1628 /* This API is wrong for special case conversions since we may need to
1629  * return several Unicode characters for a single Unicode character
1630  * (see lib/unicore/SpecCase.txt) The SWASHGET in lib/utf8_heavy.pl is
1631  * the lower-level routine, and it is similarly broken for returning
1632  * multiple values.  --jhi */
1633 UV
1634 Perl_swash_fetch(pTHX_ SV *sv, U8 *ptr, bool do_utf8)
1635 {
1636     HV* hv = (HV*)SvRV(sv);
1637     U32 klen;
1638     U32 off;
1639     STRLEN slen;
1640     STRLEN needents;
1641     U8 *tmps = NULL;
1642     U32 bit;
1643     SV *retval;
1644     U8 tmputf8[2];
1645     UV c = NATIVE_TO_ASCII(*ptr);
1646 
1647     if (!do_utf8 && !UNI_IS_INVARIANT(c)) {
1648         tmputf8[0] = (U8)UTF8_EIGHT_BIT_HI(c);
1649         tmputf8[1] = (U8)UTF8_EIGHT_BIT_LO(c);
1650         ptr = tmputf8;
1651     }
1652     /* Given a UTF-X encoded char 0xAA..0xYY,0xZZ
1653      * then the "swatch" is a vec() for al the chars which start
1654      * with 0xAA..0xYY
1655      * So the key in the hash (klen) is length of encoded char -1
1656      */
1657     klen = UTF8SKIP(ptr) - 1;
1658     off  = ptr[klen];
1659 
1660     if (klen == 0)
1661      {
1662       /* If char in invariant then swatch is for all the invariant chars
1663        * In both UTF-8 and UTF-8-MOD that happens to be UTF_CONTINUATION_MARK
1664        */
1665       needents = UTF_CONTINUATION_MARK;
1666       off      = NATIVE_TO_UTF(ptr[klen]);
1667      }
1668     else
1669      {
1670       /* If char is encoded then swatch is for the prefix */
1671       needents = (1 << UTF_ACCUMULATION_SHIFT);
1672       off      = NATIVE_TO_UTF(ptr[klen]) & UTF_CONTINUATION_MASK;
1673      }
1674 
1675     /*
1676      * This single-entry cache saves about 1/3 of the utf8 overhead in test
1677      * suite.  (That is, only 7-8% overall over just a hash cache.  Still,
1678      * it's nothing to sniff at.)  Pity we usually come through at least
1679      * two function calls to get here...
1680      *
1681      * NB: this code assumes that swatches are never modified, once generated!
1682      */
1683 
1684     if (hv   == PL_last_swash_hv &&
1685 	klen == PL_last_swash_klen &&
1686 	(!klen || memEQ((char *)ptr, (char *)PL_last_swash_key, klen)) )
1687     {
1688 	tmps = PL_last_swash_tmps;
1689 	slen = PL_last_swash_slen;
1690     }
1691     else {
1692 	/* Try our second-level swatch cache, kept in a hash. */
1693 	SV** svp = hv_fetch(hv, (char*)ptr, klen, FALSE);
1694 
1695 	/* If not cached, generate it via utf8::SWASHGET */
1696 	if (!svp || !SvPOK(*svp) || !(tmps = (U8*)SvPV(*svp, slen))) {
1697 	    dSP;
1698 	    /* We use utf8n_to_uvuni() as we want an index into
1699 	       Unicode tables, not a native character number.
1700 	     */
1701 	    UV code_point = utf8n_to_uvuni(ptr, UTF8_MAXLEN, 0,
1702 					   ckWARN(WARN_UTF8) ?
1703 					   0 : UTF8_ALLOW_ANY);
1704 	    SV *errsv_save;
1705 	    ENTER;
1706 	    SAVETMPS;
1707 	    save_re_context();
1708 	    PUSHSTACKi(PERLSI_MAGIC);
1709 	    PUSHMARK(SP);
1710 	    EXTEND(SP,3);
1711 	    PUSHs((SV*)sv);
1712 	    /* On EBCDIC & ~(0xA0-1) isn't a useful thing to do */
1713 	    PUSHs(sv_2mortal(newSViv((klen) ?
1714 				     (code_point & ~(needents - 1)) : 0)));
1715 	    PUSHs(sv_2mortal(newSViv(needents)));
1716 	    PUTBACK;
1717 	    errsv_save = newSVsv(ERRSV);
1718 	    if (call_method("SWASHGET", G_SCALAR))
1719 		retval = newSVsv(*PL_stack_sp--);
1720 	    else
1721 		retval = &PL_sv_undef;
1722 	    if (!SvTRUE(ERRSV))
1723 		sv_setsv(ERRSV, errsv_save);
1724 	    SvREFCNT_dec(errsv_save);
1725 	    POPSTACK;
1726 	    FREETMPS;
1727 	    LEAVE;
1728 	    if (IN_PERL_COMPILETIME)
1729 		PL_curcop->op_private = (U8)(PL_hints & HINT_PRIVATE_MASK);
1730 
1731 	    svp = hv_store(hv, (char*)ptr, klen, retval, 0);
1732 
1733 	    if (!svp || !(tmps = (U8*)SvPV(*svp, slen)) || (slen << 3) < needents)
1734 		Perl_croak(aTHX_ "SWASHGET didn't return result of proper length");
1735 	}
1736 
1737 	PL_last_swash_hv = hv;
1738 	PL_last_swash_klen = klen;
1739 	PL_last_swash_tmps = tmps;
1740 	PL_last_swash_slen = slen;
1741 	if (klen)
1742 	    Copy(ptr, PL_last_swash_key, klen, U8);
1743     }
1744 
1745     switch ((int)((slen << 3) / needents)) {
1746     case 1:
1747 	bit = 1 << (off & 7);
1748 	off >>= 3;
1749 	return (tmps[off] & bit) != 0;
1750     case 8:
1751 	return tmps[off];
1752     case 16:
1753 	off <<= 1;
1754 	return (tmps[off] << 8) + tmps[off + 1] ;
1755     case 32:
1756 	off <<= 2;
1757 	return (tmps[off] << 24) + (tmps[off+1] << 16) + (tmps[off+2] << 8) + tmps[off + 3] ;
1758     }
1759     Perl_croak(aTHX_ "panic: swash_fetch");
1760     return 0;
1761 }
1762 
1763 
1764 /*
1765 =for apidoc A|U8 *|uvchr_to_utf8|U8 *d|UV uv
1766 
1767 Adds the UTF-8 representation of the Native codepoint C<uv> to the end
1768 of the string C<d>; C<d> should be have at least C<UTF8_MAXLEN+1> free
1769 bytes available. The return value is the pointer to the byte after the
1770 end of the new character. In other words,
1771 
1772     d = uvchr_to_utf8(d, uv);
1773 
1774 is the recommended wide native character-aware way of saying
1775 
1776     *(d++) = uv;
1777 
1778 =cut
1779 */
1780 
1781 /* On ASCII machines this is normally a macro but we want a
1782    real function in case XS code wants it
1783 */
1784 #undef Perl_uvchr_to_utf8
1785 U8 *
1786 Perl_uvchr_to_utf8(pTHX_ U8 *d, UV uv)
1787 {
1788     return Perl_uvuni_to_utf8_flags(aTHX_ d, NATIVE_TO_UNI(uv), 0);
1789 }
1790 
1791 U8 *
1792 Perl_uvchr_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags)
1793 {
1794     return Perl_uvuni_to_utf8_flags(aTHX_ d, NATIVE_TO_UNI(uv), flags);
1795 }
1796 
1797 /*
1798 =for apidoc A|UV|utf8n_to_uvchr|U8 *s|STRLEN curlen|STRLEN *retlen|U32 flags
1799 
1800 Returns the native character value of the first character in the string C<s>
1801 which is assumed to be in UTF-8 encoding; C<retlen> will be set to the
1802 length, in bytes, of that character.
1803 
1804 Allows length and flags to be passed to low level routine.
1805 
1806 =cut
1807 */
1808 /* On ASCII machines this is normally a macro but we want
1809    a real function in case XS code wants it
1810 */
1811 #undef Perl_utf8n_to_uvchr
1812 UV
1813 Perl_utf8n_to_uvchr(pTHX_ U8 *s, STRLEN curlen, STRLEN *retlen, U32 flags)
1814 {
1815     UV uv = Perl_utf8n_to_uvuni(aTHX_ s, curlen, retlen, flags);
1816     return UNI_TO_NATIVE(uv);
1817 }
1818 
1819 /*
1820 =for apidoc A|char *|pv_uni_display|SV *dsv|U8 *spv|STRLEN len|STRLEN pvlim|UV flags
1821 
1822 Build to the scalar dsv a displayable version of the string spv,
1823 length len, the displayable version being at most pvlim bytes long
1824 (if longer, the rest is truncated and "..." will be appended).
1825 
1826 The flags argument can have UNI_DISPLAY_ISPRINT set to display
1827 isPRINT()able characters as themselves, UNI_DISPLAY_BACKSLASH
1828 to display the \\[nrfta\\] as the backslashed versions (like '\n')
1829 (UNI_DISPLAY_BACKSLASH is preferred over UNI_DISPLAY_ISPRINT for \\).
1830 UNI_DISPLAY_QQ (and its alias UNI_DISPLAY_REGEX) have both
1831 UNI_DISPLAY_BACKSLASH and UNI_DISPLAY_ISPRINT turned on.
1832 
1833 The pointer to the PV of the dsv is returned.
1834 
1835 =cut */
1836 char *
1837 Perl_pv_uni_display(pTHX_ SV *dsv, U8 *spv, STRLEN len, STRLEN pvlim, UV flags)
1838 {
1839     int truncated = 0;
1840     char *s, *e;
1841 
1842     sv_setpvn(dsv, "", 0);
1843     for (s = (char *)spv, e = s + len; s < e; s += UTF8SKIP(s)) {
1844 	 UV u;
1845 	 bool ok = FALSE;
1846 
1847 	 if (pvlim && SvCUR(dsv) >= pvlim) {
1848 	      truncated++;
1849 	      break;
1850 	 }
1851 	 u = utf8_to_uvchr((U8*)s, 0);
1852 	 if (u < 256) {
1853 	     if (!ok && (flags & UNI_DISPLAY_BACKSLASH)) {
1854 	         switch (u & 0xFF) {
1855 		 case '\n':
1856 		     Perl_sv_catpvf(aTHX_ dsv, "\\n"); ok = TRUE; break;
1857 		 case '\r':
1858 		     Perl_sv_catpvf(aTHX_ dsv, "\\r"); ok = TRUE; break;
1859 		 case '\t':
1860 		     Perl_sv_catpvf(aTHX_ dsv, "\\t"); ok = TRUE; break;
1861 		 case '\f':
1862 		     Perl_sv_catpvf(aTHX_ dsv, "\\f"); ok = TRUE; break;
1863 		 case '\a':
1864 		     Perl_sv_catpvf(aTHX_ dsv, "\\a"); ok = TRUE; break;
1865 		 case '\\':
1866 		     Perl_sv_catpvf(aTHX_ dsv, "\\\\" ); ok = TRUE; break;
1867 		 default: break;
1868 		 }
1869 	     }
1870 	     /* isPRINT() is the locale-blind version. */
1871 	     if (!ok && (flags & UNI_DISPLAY_ISPRINT) && isPRINT(u & 0xFF)) {
1872 	         Perl_sv_catpvf(aTHX_ dsv, "%c", (char)(u & 0xFF));
1873 		 ok = TRUE;
1874 	     }
1875 	 }
1876 	 if (!ok)
1877 	     Perl_sv_catpvf(aTHX_ dsv, "\\x{%"UVxf"}", u);
1878     }
1879     if (truncated)
1880 	 sv_catpvn(dsv, "...", 3);
1881 
1882     return SvPVX(dsv);
1883 }
1884 
1885 /*
1886 =for apidoc A|char *|sv_uni_display|SV *dsv|SV *ssv|STRLEN pvlim|UV flags
1887 
1888 Build to the scalar dsv a displayable version of the scalar sv,
1889 the displayable version being at most pvlim bytes long
1890 (if longer, the rest is truncated and "..." will be appended).
1891 
1892 The flags argument is as in pv_uni_display().
1893 
1894 The pointer to the PV of the dsv is returned.
1895 
1896 =cut */
1897 char *
1898 Perl_sv_uni_display(pTHX_ SV *dsv, SV *ssv, STRLEN pvlim, UV flags)
1899 {
1900      return Perl_pv_uni_display(aTHX_ dsv, (U8*)SvPVX(ssv), SvCUR(ssv),
1901 				pvlim, flags);
1902 }
1903 
1904 /*
1905 =for apidoc A|I32|ibcmp_utf8|const char *s1|char **pe1|register UV l1|bool u1|const char *s2|char **pe2|register UV l2|bool u2
1906 
1907 Return true if the strings s1 and s2 differ case-insensitively, false
1908 if not (if they are equal case-insensitively).  If u1 is true, the
1909 string s1 is assumed to be in UTF-8-encoded Unicode.  If u2 is true,
1910 the string s2 is assumed to be in UTF-8-encoded Unicode.  If u1 or u2
1911 are false, the respective string is assumed to be in native 8-bit
1912 encoding.
1913 
1914 If the pe1 and pe2 are non-NULL, the scanning pointers will be copied
1915 in there (they will point at the beginning of the I<next> character).
1916 If the pointers behind pe1 or pe2 are non-NULL, they are the end
1917 pointers beyond which scanning will not continue under any
1918 circustances.  If the byte lengths l1 and l2 are non-zero, s1+l1 and
1919 s2+l2 will be used as goal end pointers that will also stop the scan,
1920 and which qualify towards defining a successful match: all the scans
1921 that define an explicit length must reach their goal pointers for
1922 a match to succeed).
1923 
1924 For case-insensitiveness, the "casefolding" of Unicode is used
1925 instead of upper/lowercasing both the characters, see
1926 http://www.unicode.org/unicode/reports/tr21/ (Case Mappings).
1927 
1928 =cut */
1929 I32
1930 Perl_ibcmp_utf8(pTHX_ const char *s1, char **pe1, register UV l1, bool u1, const char *s2, char **pe2, register UV l2, bool u2)
1931 {
1932      register U8 *p1  = (U8*)s1;
1933      register U8 *p2  = (U8*)s2;
1934      register U8 *e1 = 0, *f1 = 0, *q1 = 0;
1935      register U8 *e2 = 0, *f2 = 0, *q2 = 0;
1936      STRLEN n1 = 0, n2 = 0;
1937      U8 foldbuf1[UTF8_MAXLEN_FOLD+1];
1938      U8 foldbuf2[UTF8_MAXLEN_FOLD+1];
1939      U8 natbuf[1+1];
1940      STRLEN foldlen1, foldlen2;
1941      bool match;
1942 
1943      if (pe1)
1944 	  e1 = *(U8**)pe1;
1945      if (e1 == 0 || (l1 && l1 < (UV)(e1 - (U8*)s1)))
1946 	  f1 = (U8*)s1 + l1;
1947      if (pe2)
1948 	  e2 = *(U8**)pe2;
1949      if (e2 == 0 || (l2 && l2 < (UV)(e2 - (U8*)s2)))
1950 	  f2 = (U8*)s2 + l2;
1951 
1952      if ((e1 == 0 && f1 == 0) || (e2 == 0 && f2 == 0) || (f1 == 0 && f2 == 0))
1953 	  return 1; /* mismatch; possible infinite loop or false positive */
1954 
1955      if (!u1 || !u2)
1956 	  natbuf[1] = 0; /* Need to terminate the buffer. */
1957 
1958      while ((e1 == 0 || p1 < e1) &&
1959 	    (f1 == 0 || p1 < f1) &&
1960 	    (e2 == 0 || p2 < e2) &&
1961 	    (f2 == 0 || p2 < f2)) {
1962 	  if (n1 == 0) {
1963 	       if (u1)
1964 		    to_utf8_fold(p1, foldbuf1, &foldlen1);
1965 	       else {
1966 		    natbuf[0] = *p1;
1967 		    to_utf8_fold(natbuf, foldbuf1, &foldlen1);
1968 	       }
1969 	       q1 = foldbuf1;
1970 	       n1 = foldlen1;
1971 	  }
1972 	  if (n2 == 0) {
1973 	       if (u2)
1974 		    to_utf8_fold(p2, foldbuf2, &foldlen2);
1975 	       else {
1976 		    natbuf[0] = *p2;
1977 		    to_utf8_fold(natbuf, foldbuf2, &foldlen2);
1978 	       }
1979 	       q2 = foldbuf2;
1980 	       n2 = foldlen2;
1981 	  }
1982 	  while (n1 && n2) {
1983 	       if ( UTF8SKIP(q1) != UTF8SKIP(q2) ||
1984 		   (UTF8SKIP(q1) == 1 && *q1 != *q2) ||
1985 		    memNE((char*)q1, (char*)q2, UTF8SKIP(q1)) )
1986 		   return 1; /* mismatch */
1987 	       n1 -= UTF8SKIP(q1);
1988 	       q1 += UTF8SKIP(q1);
1989 	       n2 -= UTF8SKIP(q2);
1990 	       q2 += UTF8SKIP(q2);
1991 	  }
1992 	  if (n1 == 0)
1993 	       p1 += u1 ? UTF8SKIP(p1) : 1;
1994 	  if (n2 == 0)
1995 	       p2 += u2 ? UTF8SKIP(p2) : 1;
1996 
1997      }
1998 
1999      /* A match is defined by all the scans that specified
2000       * an explicit length reaching their final goals. */
2001      match = (f1 == 0 || p1 == f1) && (f2 == 0 || p2 == f2);
2002 
2003      if (match) {
2004 	  if (pe1)
2005 	       *pe1 = (char*)p1;
2006 	  if (pe2)
2007 	       *pe2 = (char*)p2;
2008      }
2009 
2010      return match ? 0 : 1; /* 0 match, 1 mismatch */
2011 }
2012 
2013