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Revision 1502 - (show annotations)
Mon Sep 15 13:56:18 2014 UTC (5 years, 1 month ago) by ph10
File MIME type: text/plain
File size: 47166 byte(s)
Files tidied for 8.36-RC1.
1 /*************************************************
2 * Perl-Compatible Regular Expressions *
3 *************************************************/
4
5 /* PCRE is a library of functions to support regular expressions whose syntax
6 and semantics are as close as possible to those of the Perl 5 language.
7
8 Written by Philip Hazel
9 Copyright (c) 1997-2012 University of Cambridge
10
11 -----------------------------------------------------------------------------
12 Redistribution and use in source and binary forms, with or without
13 modification, are permitted provided that the following conditions are met:
14
15 * Redistributions of source code must retain the above copyright notice,
16 this list of conditions and the following disclaimer.
17
18 * Redistributions in binary form must reproduce the above copyright
19 notice, this list of conditions and the following disclaimer in the
20 documentation and/or other materials provided with the distribution.
21
22 * Neither the name of the University of Cambridge nor the names of its
23 contributors may be used to endorse or promote products derived from
24 this software without specific prior written permission.
25
26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
27 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
30 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 POSSIBILITY OF SUCH DAMAGE.
37 -----------------------------------------------------------------------------
38 */
39
40
41 /* This module contains the external function pcre_study(), along with local
42 supporting functions. */
43
44
45 #ifdef HAVE_CONFIG_H
46 #include "config.h"
47 #endif
48
49 #include "pcre_internal.h"
50
51 #define SET_BIT(c) start_bits[c/8] |= (1 << (c&7))
52
53 /* Returns from set_start_bits() */
54
55 enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE, SSB_UNKNOWN };
56
57
58
59 /*************************************************
60 * Find the minimum subject length for a group *
61 *************************************************/
62
63 /* Scan a parenthesized group and compute the minimum length of subject that
64 is needed to match it. This is a lower bound; it does not mean there is a
65 string of that length that matches. In UTF8 mode, the result is in characters
66 rather than bytes.
67
68 Arguments:
69 re compiled pattern block
70 code pointer to start of group (the bracket)
71 startcode pointer to start of the whole pattern's code
72 options the compiling options
73 int RECURSE depth
74
75 Returns: the minimum length
76 -1 if \C in UTF-8 mode or (*ACCEPT) was encountered
77 -2 internal error (missing capturing bracket)
78 -3 internal error (opcode not listed)
79 */
80
81 static int
82 find_minlength(const REAL_PCRE *re, const pcre_uchar *code,
83 const pcre_uchar *startcode, int options, int recurse_depth)
84 {
85 int length = -1;
86 /* PCRE_UTF16 has the same value as PCRE_UTF8. */
87 BOOL utf = (options & PCRE_UTF8) != 0;
88 BOOL had_recurse = FALSE;
89 register int branchlength = 0;
90 register pcre_uchar *cc = (pcre_uchar *)code + 1 + LINK_SIZE;
91
92 if (*code == OP_CBRA || *code == OP_SCBRA ||
93 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += IMM2_SIZE;
94
95 /* Scan along the opcodes for this branch. If we get to the end of the
96 branch, check the length against that of the other branches. */
97
98 for (;;)
99 {
100 int d, min;
101 pcre_uchar *cs, *ce;
102 register pcre_uchar op = *cc;
103
104 switch (op)
105 {
106 case OP_COND:
107 case OP_SCOND:
108
109 /* If there is only one branch in a condition, the implied branch has zero
110 length, so we don't add anything. This covers the DEFINE "condition"
111 automatically. */
112
113 cs = cc + GET(cc, 1);
114 if (*cs != OP_ALT)
115 {
116 cc = cs + 1 + LINK_SIZE;
117 break;
118 }
119
120 /* Otherwise we can fall through and treat it the same as any other
121 subpattern. */
122
123 case OP_CBRA:
124 case OP_SCBRA:
125 case OP_BRA:
126 case OP_SBRA:
127 case OP_CBRAPOS:
128 case OP_SCBRAPOS:
129 case OP_BRAPOS:
130 case OP_SBRAPOS:
131 case OP_ONCE:
132 case OP_ONCE_NC:
133 d = find_minlength(re, cc, startcode, options, recurse_depth);
134 if (d < 0) return d;
135 branchlength += d;
136 do cc += GET(cc, 1); while (*cc == OP_ALT);
137 cc += 1 + LINK_SIZE;
138 break;
139
140 /* ACCEPT makes things far too complicated; we have to give up. */
141
142 case OP_ACCEPT:
143 case OP_ASSERT_ACCEPT:
144 return -1;
145
146 /* Reached end of a branch; if it's a ket it is the end of a nested
147 call. If it's ALT it is an alternation in a nested call. If it is END it's
148 the end of the outer call. All can be handled by the same code. If an
149 ACCEPT was previously encountered, use the length that was in force at that
150 time, and pass back the shortest ACCEPT length. */
151
152 case OP_ALT:
153 case OP_KET:
154 case OP_KETRMAX:
155 case OP_KETRMIN:
156 case OP_KETRPOS:
157 case OP_END:
158 if (length < 0 || (!had_recurse && branchlength < length))
159 length = branchlength;
160 if (op != OP_ALT) return length;
161 cc += 1 + LINK_SIZE;
162 branchlength = 0;
163 had_recurse = FALSE;
164 break;
165
166 /* Skip over assertive subpatterns */
167
168 case OP_ASSERT:
169 case OP_ASSERT_NOT:
170 case OP_ASSERTBACK:
171 case OP_ASSERTBACK_NOT:
172 do cc += GET(cc, 1); while (*cc == OP_ALT);
173 /* Fall through */
174
175 /* Skip over things that don't match chars */
176
177 case OP_REVERSE:
178 case OP_CREF:
179 case OP_DNCREF:
180 case OP_RREF:
181 case OP_DNRREF:
182 case OP_DEF:
183 case OP_CALLOUT:
184 case OP_SOD:
185 case OP_SOM:
186 case OP_EOD:
187 case OP_EODN:
188 case OP_CIRC:
189 case OP_CIRCM:
190 case OP_DOLL:
191 case OP_DOLLM:
192 case OP_NOT_WORD_BOUNDARY:
193 case OP_WORD_BOUNDARY:
194 cc += PRIV(OP_lengths)[*cc];
195 break;
196
197 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
198
199 case OP_BRAZERO:
200 case OP_BRAMINZERO:
201 case OP_BRAPOSZERO:
202 case OP_SKIPZERO:
203 cc += PRIV(OP_lengths)[*cc];
204 do cc += GET(cc, 1); while (*cc == OP_ALT);
205 cc += 1 + LINK_SIZE;
206 break;
207
208 /* Handle literal characters and + repetitions */
209
210 case OP_CHAR:
211 case OP_CHARI:
212 case OP_NOT:
213 case OP_NOTI:
214 case OP_PLUS:
215 case OP_PLUSI:
216 case OP_MINPLUS:
217 case OP_MINPLUSI:
218 case OP_POSPLUS:
219 case OP_POSPLUSI:
220 case OP_NOTPLUS:
221 case OP_NOTPLUSI:
222 case OP_NOTMINPLUS:
223 case OP_NOTMINPLUSI:
224 case OP_NOTPOSPLUS:
225 case OP_NOTPOSPLUSI:
226 branchlength++;
227 cc += 2;
228 #ifdef SUPPORT_UTF
229 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
230 #endif
231 break;
232
233 case OP_TYPEPLUS:
234 case OP_TYPEMINPLUS:
235 case OP_TYPEPOSPLUS:
236 branchlength++;
237 cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
238 break;
239
240 /* Handle exact repetitions. The count is already in characters, but we
241 need to skip over a multibyte character in UTF8 mode. */
242
243 case OP_EXACT:
244 case OP_EXACTI:
245 case OP_NOTEXACT:
246 case OP_NOTEXACTI:
247 branchlength += GET2(cc,1);
248 cc += 2 + IMM2_SIZE;
249 #ifdef SUPPORT_UTF
250 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
251 #endif
252 break;
253
254 case OP_TYPEEXACT:
255 branchlength += GET2(cc,1);
256 cc += 2 + IMM2_SIZE + ((cc[1 + IMM2_SIZE] == OP_PROP
257 || cc[1 + IMM2_SIZE] == OP_NOTPROP)? 2 : 0);
258 break;
259
260 /* Handle single-char non-literal matchers */
261
262 case OP_PROP:
263 case OP_NOTPROP:
264 cc += 2;
265 /* Fall through */
266
267 case OP_NOT_DIGIT:
268 case OP_DIGIT:
269 case OP_NOT_WHITESPACE:
270 case OP_WHITESPACE:
271 case OP_NOT_WORDCHAR:
272 case OP_WORDCHAR:
273 case OP_ANY:
274 case OP_ALLANY:
275 case OP_EXTUNI:
276 case OP_HSPACE:
277 case OP_NOT_HSPACE:
278 case OP_VSPACE:
279 case OP_NOT_VSPACE:
280 branchlength++;
281 cc++;
282 break;
283
284 /* "Any newline" might match two characters, but it also might match just
285 one. */
286
287 case OP_ANYNL:
288 branchlength += 1;
289 cc++;
290 break;
291
292 /* The single-byte matcher means we can't proceed in UTF-8 mode. (In
293 non-UTF-8 mode \C will actually be turned into OP_ALLANY, so won't ever
294 appear, but leave the code, just in case.) */
295
296 case OP_ANYBYTE:
297 #ifdef SUPPORT_UTF
298 if (utf) return -1;
299 #endif
300 branchlength++;
301 cc++;
302 break;
303
304 /* For repeated character types, we have to test for \p and \P, which have
305 an extra two bytes of parameters. */
306
307 case OP_TYPESTAR:
308 case OP_TYPEMINSTAR:
309 case OP_TYPEQUERY:
310 case OP_TYPEMINQUERY:
311 case OP_TYPEPOSSTAR:
312 case OP_TYPEPOSQUERY:
313 if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
314 cc += PRIV(OP_lengths)[op];
315 break;
316
317 case OP_TYPEUPTO:
318 case OP_TYPEMINUPTO:
319 case OP_TYPEPOSUPTO:
320 if (cc[1 + IMM2_SIZE] == OP_PROP
321 || cc[1 + IMM2_SIZE] == OP_NOTPROP) cc += 2;
322 cc += PRIV(OP_lengths)[op];
323 break;
324
325 /* Check a class for variable quantification */
326
327 case OP_CLASS:
328 case OP_NCLASS:
329 #if defined SUPPORT_UTF || defined COMPILE_PCRE16 || defined COMPILE_PCRE32
330 case OP_XCLASS:
331 /* The original code caused an unsigned overflow in 64 bit systems,
332 so now we use a conditional statement. */
333 if (op == OP_XCLASS)
334 cc += GET(cc, 1);
335 else
336 cc += PRIV(OP_lengths)[OP_CLASS];
337 #else
338 cc += PRIV(OP_lengths)[OP_CLASS];
339 #endif
340
341 switch (*cc)
342 {
343 case OP_CRPLUS:
344 case OP_CRMINPLUS:
345 case OP_CRPOSPLUS:
346 branchlength++;
347 /* Fall through */
348
349 case OP_CRSTAR:
350 case OP_CRMINSTAR:
351 case OP_CRQUERY:
352 case OP_CRMINQUERY:
353 case OP_CRPOSSTAR:
354 case OP_CRPOSQUERY:
355 cc++;
356 break;
357
358 case OP_CRRANGE:
359 case OP_CRMINRANGE:
360 case OP_CRPOSRANGE:
361 branchlength += GET2(cc,1);
362 cc += 1 + 2 * IMM2_SIZE;
363 break;
364
365 default:
366 branchlength++;
367 break;
368 }
369 break;
370
371 /* Backreferences and subroutine calls are treated in the same way: we find
372 the minimum length for the subpattern. A recursion, however, causes an
373 a flag to be set that causes the length of this branch to be ignored. The
374 logic is that a recursion can only make sense if there is another
375 alternation that stops the recursing. That will provide the minimum length
376 (when no recursion happens). A backreference within the group that it is
377 referencing behaves in the same way.
378
379 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
380 matches an empty string (by default it causes a matching failure), so in
381 that case we must set the minimum length to zero. */
382
383 case OP_DNREF: /* Duplicate named pattern back reference */
384 case OP_DNREFI:
385 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
386 {
387 int count = GET2(cc, 1+IMM2_SIZE);
388 pcre_uchar *slot = (pcre_uchar *)re +
389 re->name_table_offset + GET2(cc, 1) * re->name_entry_size;
390 d = INT_MAX;
391 while (count-- > 0)
392 {
393 ce = cs = (pcre_uchar *)PRIV(find_bracket)(startcode, utf, GET2(slot, 0));
394 if (cs == NULL) return -2;
395 do ce += GET(ce, 1); while (*ce == OP_ALT);
396 if (cc > cs && cc < ce)
397 {
398 d = 0;
399 had_recurse = TRUE;
400 break;
401 }
402 else
403 {
404 int dd = find_minlength(re, cs, startcode, options, recurse_depth);
405 if (dd < d) d = dd;
406 }
407 slot += re->name_entry_size;
408 }
409 }
410 else d = 0;
411 cc += 1 + 2*IMM2_SIZE;
412 goto REPEAT_BACK_REFERENCE;
413
414 case OP_REF: /* Single back reference */
415 case OP_REFI:
416 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
417 {
418 ce = cs = (pcre_uchar *)PRIV(find_bracket)(startcode, utf, GET2(cc, 1));
419 if (cs == NULL) return -2;
420 do ce += GET(ce, 1); while (*ce == OP_ALT);
421 if (cc > cs && cc < ce)
422 {
423 d = 0;
424 had_recurse = TRUE;
425 }
426 else
427 {
428 d = find_minlength(re, cs, startcode, options, recurse_depth);
429 }
430 }
431 else d = 0;
432 cc += 1 + IMM2_SIZE;
433
434 /* Handle repeated back references */
435
436 REPEAT_BACK_REFERENCE:
437 switch (*cc)
438 {
439 case OP_CRSTAR:
440 case OP_CRMINSTAR:
441 case OP_CRQUERY:
442 case OP_CRMINQUERY:
443 case OP_CRPOSSTAR:
444 case OP_CRPOSQUERY:
445 min = 0;
446 cc++;
447 break;
448
449 case OP_CRPLUS:
450 case OP_CRMINPLUS:
451 case OP_CRPOSPLUS:
452 min = 1;
453 cc++;
454 break;
455
456 case OP_CRRANGE:
457 case OP_CRMINRANGE:
458 case OP_CRPOSRANGE:
459 min = GET2(cc, 1);
460 cc += 1 + 2 * IMM2_SIZE;
461 break;
462
463 default:
464 min = 1;
465 break;
466 }
467
468 branchlength += min * d;
469 break;
470
471 /* We can easily detect direct recursion, but not mutual recursion. This is
472 caught by a recursion depth count. */
473
474 case OP_RECURSE:
475 cs = ce = (pcre_uchar *)startcode + GET(cc, 1);
476 do ce += GET(ce, 1); while (*ce == OP_ALT);
477 if ((cc > cs && cc < ce) || recurse_depth > 10)
478 had_recurse = TRUE;
479 else
480 {
481 branchlength += find_minlength(re, cs, startcode, options,
482 recurse_depth + 1);
483 }
484 cc += 1 + LINK_SIZE;
485 break;
486
487 /* Anything else does not or need not match a character. We can get the
488 item's length from the table, but for those that can match zero occurrences
489 of a character, we must take special action for UTF-8 characters. As it
490 happens, the "NOT" versions of these opcodes are used at present only for
491 ASCII characters, so they could be omitted from this list. However, in
492 future that may change, so we include them here so as not to leave a
493 gotcha for a future maintainer. */
494
495 case OP_UPTO:
496 case OP_UPTOI:
497 case OP_NOTUPTO:
498 case OP_NOTUPTOI:
499 case OP_MINUPTO:
500 case OP_MINUPTOI:
501 case OP_NOTMINUPTO:
502 case OP_NOTMINUPTOI:
503 case OP_POSUPTO:
504 case OP_POSUPTOI:
505 case OP_NOTPOSUPTO:
506 case OP_NOTPOSUPTOI:
507
508 case OP_STAR:
509 case OP_STARI:
510 case OP_NOTSTAR:
511 case OP_NOTSTARI:
512 case OP_MINSTAR:
513 case OP_MINSTARI:
514 case OP_NOTMINSTAR:
515 case OP_NOTMINSTARI:
516 case OP_POSSTAR:
517 case OP_POSSTARI:
518 case OP_NOTPOSSTAR:
519 case OP_NOTPOSSTARI:
520
521 case OP_QUERY:
522 case OP_QUERYI:
523 case OP_NOTQUERY:
524 case OP_NOTQUERYI:
525 case OP_MINQUERY:
526 case OP_MINQUERYI:
527 case OP_NOTMINQUERY:
528 case OP_NOTMINQUERYI:
529 case OP_POSQUERY:
530 case OP_POSQUERYI:
531 case OP_NOTPOSQUERY:
532 case OP_NOTPOSQUERYI:
533
534 cc += PRIV(OP_lengths)[op];
535 #ifdef SUPPORT_UTF
536 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
537 #endif
538 break;
539
540 /* Skip these, but we need to add in the name length. */
541
542 case OP_MARK:
543 case OP_PRUNE_ARG:
544 case OP_SKIP_ARG:
545 case OP_THEN_ARG:
546 cc += PRIV(OP_lengths)[op] + cc[1];
547 break;
548
549 /* The remaining opcodes are just skipped over. */
550
551 case OP_CLOSE:
552 case OP_COMMIT:
553 case OP_FAIL:
554 case OP_PRUNE:
555 case OP_SET_SOM:
556 case OP_SKIP:
557 case OP_THEN:
558 cc += PRIV(OP_lengths)[op];
559 break;
560
561 /* This should not occur: we list all opcodes explicitly so that when
562 new ones get added they are properly considered. */
563
564 default:
565 return -3;
566 }
567 }
568 /* Control never gets here */
569 }
570
571
572
573 /*************************************************
574 * Set a bit and maybe its alternate case *
575 *************************************************/
576
577 /* Given a character, set its first byte's bit in the table, and also the
578 corresponding bit for the other version of a letter if we are caseless. In
579 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
580 when Unicode property support is available.
581
582 Arguments:
583 start_bits points to the bit map
584 p points to the character
585 caseless the caseless flag
586 cd the block with char table pointers
587 utf TRUE for UTF-8 / UTF-16 / UTF-32 mode
588
589 Returns: pointer after the character
590 */
591
592 static const pcre_uchar *
593 set_table_bit(pcre_uint8 *start_bits, const pcre_uchar *p, BOOL caseless,
594 compile_data *cd, BOOL utf)
595 {
596 pcre_uint32 c = *p;
597
598 #ifdef COMPILE_PCRE8
599 SET_BIT(c);
600
601 #ifdef SUPPORT_UTF
602 if (utf && c > 127)
603 {
604 GETCHARINC(c, p);
605 #ifdef SUPPORT_UCP
606 if (caseless)
607 {
608 pcre_uchar buff[6];
609 c = UCD_OTHERCASE(c);
610 (void)PRIV(ord2utf)(c, buff);
611 SET_BIT(buff[0]);
612 }
613 #endif /* Not SUPPORT_UCP */
614 return p;
615 }
616 #else /* Not SUPPORT_UTF */
617 (void)(utf); /* Stops warning for unused parameter */
618 #endif /* SUPPORT_UTF */
619
620 /* Not UTF-8 mode, or character is less than 127. */
621
622 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
623 return p + 1;
624 #endif /* COMPILE_PCRE8 */
625
626 #if defined COMPILE_PCRE16 || defined COMPILE_PCRE32
627 if (c > 0xff)
628 {
629 c = 0xff;
630 caseless = FALSE;
631 }
632 SET_BIT(c);
633
634 #ifdef SUPPORT_UTF
635 if (utf && c > 127)
636 {
637 GETCHARINC(c, p);
638 #ifdef SUPPORT_UCP
639 if (caseless)
640 {
641 c = UCD_OTHERCASE(c);
642 if (c > 0xff)
643 c = 0xff;
644 SET_BIT(c);
645 }
646 #endif /* SUPPORT_UCP */
647 return p;
648 }
649 #else /* Not SUPPORT_UTF */
650 (void)(utf); /* Stops warning for unused parameter */
651 #endif /* SUPPORT_UTF */
652
653 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
654 return p + 1;
655 #endif
656 }
657
658
659
660 /*************************************************
661 * Set bits for a positive character type *
662 *************************************************/
663
664 /* This function sets starting bits for a character type. In UTF-8 mode, we can
665 only do a direct setting for bytes less than 128, as otherwise there can be
666 confusion with bytes in the middle of UTF-8 characters. In a "traditional"
667 environment, the tables will only recognize ASCII characters anyway, but in at
668 least one Windows environment, some higher bytes bits were set in the tables.
669 So we deal with that case by considering the UTF-8 encoding.
670
671 Arguments:
672 start_bits the starting bitmap
673 cbit type the type of character wanted
674 table_limit 32 for non-UTF-8; 16 for UTF-8
675 cd the block with char table pointers
676
677 Returns: nothing
678 */
679
680 static void
681 set_type_bits(pcre_uint8 *start_bits, int cbit_type, unsigned int table_limit,
682 compile_data *cd)
683 {
684 register pcre_uint32 c;
685 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
686 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
687 if (table_limit == 32) return;
688 for (c = 128; c < 256; c++)
689 {
690 if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
691 {
692 pcre_uchar buff[6];
693 (void)PRIV(ord2utf)(c, buff);
694 SET_BIT(buff[0]);
695 }
696 }
697 #endif
698 }
699
700
701 /*************************************************
702 * Set bits for a negative character type *
703 *************************************************/
704
705 /* This function sets starting bits for a negative character type such as \D.
706 In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
707 otherwise there can be confusion with bytes in the middle of UTF-8 characters.
708 Unlike in the positive case, where we can set appropriate starting bits for
709 specific high-valued UTF-8 characters, in this case we have to set the bits for
710 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
711 0xc0 (192) for simplicity.
712
713 Arguments:
714 start_bits the starting bitmap
715 cbit type the type of character wanted
716 table_limit 32 for non-UTF-8; 16 for UTF-8
717 cd the block with char table pointers
718
719 Returns: nothing
720 */
721
722 static void
723 set_nottype_bits(pcre_uint8 *start_bits, int cbit_type, unsigned int table_limit,
724 compile_data *cd)
725 {
726 register pcre_uint32 c;
727 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
728 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
729 if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
730 #endif
731 }
732
733
734
735 /*************************************************
736 * Create bitmap of starting bytes *
737 *************************************************/
738
739 /* This function scans a compiled unanchored expression recursively and
740 attempts to build a bitmap of the set of possible starting bytes. As time goes
741 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
742 useful for parenthesized groups in patterns such as (a*)b where the group
743 provides some optional starting bytes but scanning must continue at the outer
744 level to find at least one mandatory byte. At the outermost level, this
745 function fails unless the result is SSB_DONE.
746
747 Arguments:
748 code points to an expression
749 start_bits points to a 32-byte table, initialized to 0
750 utf TRUE if in UTF-8 / UTF-16 / UTF-32 mode
751 cd the block with char table pointers
752
753 Returns: SSB_FAIL => Failed to find any starting bytes
754 SSB_DONE => Found mandatory starting bytes
755 SSB_CONTINUE => Found optional starting bytes
756 SSB_UNKNOWN => Hit an unrecognized opcode
757 */
758
759 static int
760 set_start_bits(const pcre_uchar *code, pcre_uint8 *start_bits, BOOL utf,
761 compile_data *cd)
762 {
763 register pcre_uint32 c;
764 int yield = SSB_DONE;
765 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
766 int table_limit = utf? 16:32;
767 #else
768 int table_limit = 32;
769 #endif
770
771 #if 0
772 /* ========================================================================= */
773 /* The following comment and code was inserted in January 1999. In May 2006,
774 when it was observed to cause compiler warnings about unused values, I took it
775 out again. If anybody is still using OS/2, they will have to put it back
776 manually. */
777
778 /* This next statement and the later reference to dummy are here in order to
779 trick the optimizer of the IBM C compiler for OS/2 into generating correct
780 code. Apparently IBM isn't going to fix the problem, and we would rather not
781 disable optimization (in this module it actually makes a big difference, and
782 the pcre module can use all the optimization it can get). */
783
784 volatile int dummy;
785 /* ========================================================================= */
786 #endif
787
788 do
789 {
790 BOOL try_next = TRUE;
791 const pcre_uchar *tcode = code + 1 + LINK_SIZE;
792
793 if (*code == OP_CBRA || *code == OP_SCBRA ||
794 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += IMM2_SIZE;
795
796 while (try_next) /* Loop for items in this branch */
797 {
798 int rc;
799
800 switch(*tcode)
801 {
802 /* If we reach something we don't understand, it means a new opcode has
803 been created that hasn't been added to this code. Hopefully this problem
804 will be discovered during testing. */
805
806 default:
807 return SSB_UNKNOWN;
808
809 /* Fail for a valid opcode that implies no starting bits. */
810
811 case OP_ACCEPT:
812 case OP_ASSERT_ACCEPT:
813 case OP_ALLANY:
814 case OP_ANY:
815 case OP_ANYBYTE:
816 case OP_CIRC:
817 case OP_CIRCM:
818 case OP_CLOSE:
819 case OP_COMMIT:
820 case OP_COND:
821 case OP_CREF:
822 case OP_DEF:
823 case OP_DNCREF:
824 case OP_DNREF:
825 case OP_DNREFI:
826 case OP_DNRREF:
827 case OP_DOLL:
828 case OP_DOLLM:
829 case OP_END:
830 case OP_EOD:
831 case OP_EODN:
832 case OP_EXTUNI:
833 case OP_FAIL:
834 case OP_MARK:
835 case OP_NOT:
836 case OP_NOTEXACT:
837 case OP_NOTEXACTI:
838 case OP_NOTI:
839 case OP_NOTMINPLUS:
840 case OP_NOTMINPLUSI:
841 case OP_NOTMINQUERY:
842 case OP_NOTMINQUERYI:
843 case OP_NOTMINSTAR:
844 case OP_NOTMINSTARI:
845 case OP_NOTMINUPTO:
846 case OP_NOTMINUPTOI:
847 case OP_NOTPLUS:
848 case OP_NOTPLUSI:
849 case OP_NOTPOSPLUS:
850 case OP_NOTPOSPLUSI:
851 case OP_NOTPOSQUERY:
852 case OP_NOTPOSQUERYI:
853 case OP_NOTPOSSTAR:
854 case OP_NOTPOSSTARI:
855 case OP_NOTPOSUPTO:
856 case OP_NOTPOSUPTOI:
857 case OP_NOTPROP:
858 case OP_NOTQUERY:
859 case OP_NOTQUERYI:
860 case OP_NOTSTAR:
861 case OP_NOTSTARI:
862 case OP_NOTUPTO:
863 case OP_NOTUPTOI:
864 case OP_NOT_HSPACE:
865 case OP_NOT_VSPACE:
866 case OP_PRUNE:
867 case OP_PRUNE_ARG:
868 case OP_RECURSE:
869 case OP_REF:
870 case OP_REFI:
871 case OP_REVERSE:
872 case OP_RREF:
873 case OP_SCOND:
874 case OP_SET_SOM:
875 case OP_SKIP:
876 case OP_SKIP_ARG:
877 case OP_SOD:
878 case OP_SOM:
879 case OP_THEN:
880 case OP_THEN_ARG:
881 return SSB_FAIL;
882
883 /* A "real" property test implies no starting bits, but the fake property
884 PT_CLIST identifies a list of characters. These lists are short, as they
885 are used for characters with more than one "other case", so there is no
886 point in recognizing them for OP_NOTPROP. */
887
888 case OP_PROP:
889 if (tcode[1] != PT_CLIST) return SSB_FAIL;
890 {
891 const pcre_uint32 *p = PRIV(ucd_caseless_sets) + tcode[2];
892 while ((c = *p++) < NOTACHAR)
893 {
894 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
895 if (utf)
896 {
897 pcre_uchar buff[6];
898 (void)PRIV(ord2utf)(c, buff);
899 c = buff[0];
900 }
901 #endif
902 if (c > 0xff) SET_BIT(0xff); else SET_BIT(c);
903 }
904 }
905 try_next = FALSE;
906 break;
907
908 /* We can ignore word boundary tests. */
909
910 case OP_WORD_BOUNDARY:
911 case OP_NOT_WORD_BOUNDARY:
912 tcode++;
913 break;
914
915 /* If we hit a bracket or a positive lookahead assertion, recurse to set
916 bits from within the subpattern. If it can't find anything, we have to
917 give up. If it finds some mandatory character(s), we are done for this
918 branch. Otherwise, carry on scanning after the subpattern. */
919
920 case OP_BRA:
921 case OP_SBRA:
922 case OP_CBRA:
923 case OP_SCBRA:
924 case OP_BRAPOS:
925 case OP_SBRAPOS:
926 case OP_CBRAPOS:
927 case OP_SCBRAPOS:
928 case OP_ONCE:
929 case OP_ONCE_NC:
930 case OP_ASSERT:
931 rc = set_start_bits(tcode, start_bits, utf, cd);
932 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
933 if (rc == SSB_DONE) try_next = FALSE; else
934 {
935 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
936 tcode += 1 + LINK_SIZE;
937 }
938 break;
939
940 /* If we hit ALT or KET, it means we haven't found anything mandatory in
941 this branch, though we might have found something optional. For ALT, we
942 continue with the next alternative, but we have to arrange that the final
943 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
944 return SSB_CONTINUE: if this is the top level, that indicates failure,
945 but after a nested subpattern, it causes scanning to continue. */
946
947 case OP_ALT:
948 yield = SSB_CONTINUE;
949 try_next = FALSE;
950 break;
951
952 case OP_KET:
953 case OP_KETRMAX:
954 case OP_KETRMIN:
955 case OP_KETRPOS:
956 return SSB_CONTINUE;
957
958 /* Skip over callout */
959
960 case OP_CALLOUT:
961 tcode += 2 + 2*LINK_SIZE;
962 break;
963
964 /* Skip over lookbehind and negative lookahead assertions */
965
966 case OP_ASSERT_NOT:
967 case OP_ASSERTBACK:
968 case OP_ASSERTBACK_NOT:
969 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
970 tcode += 1 + LINK_SIZE;
971 break;
972
973 /* BRAZERO does the bracket, but carries on. */
974
975 case OP_BRAZERO:
976 case OP_BRAMINZERO:
977 case OP_BRAPOSZERO:
978 rc = set_start_bits(++tcode, start_bits, utf, cd);
979 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
980 /* =========================================================================
981 See the comment at the head of this function concerning the next line,
982 which was an old fudge for the benefit of OS/2.
983 dummy = 1;
984 ========================================================================= */
985 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
986 tcode += 1 + LINK_SIZE;
987 break;
988
989 /* SKIPZERO skips the bracket. */
990
991 case OP_SKIPZERO:
992 tcode++;
993 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
994 tcode += 1 + LINK_SIZE;
995 break;
996
997 /* Single-char * or ? sets the bit and tries the next item */
998
999 case OP_STAR:
1000 case OP_MINSTAR:
1001 case OP_POSSTAR:
1002 case OP_QUERY:
1003 case OP_MINQUERY:
1004 case OP_POSQUERY:
1005 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf);
1006 break;
1007
1008 case OP_STARI:
1009 case OP_MINSTARI:
1010 case OP_POSSTARI:
1011 case OP_QUERYI:
1012 case OP_MINQUERYI:
1013 case OP_POSQUERYI:
1014 tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf);
1015 break;
1016
1017 /* Single-char upto sets the bit and tries the next */
1018
1019 case OP_UPTO:
1020 case OP_MINUPTO:
1021 case OP_POSUPTO:
1022 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, FALSE, cd, utf);
1023 break;
1024
1025 case OP_UPTOI:
1026 case OP_MINUPTOI:
1027 case OP_POSUPTOI:
1028 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, TRUE, cd, utf);
1029 break;
1030
1031 /* At least one single char sets the bit and stops */
1032
1033 case OP_EXACT:
1034 tcode += IMM2_SIZE;
1035 /* Fall through */
1036 case OP_CHAR:
1037 case OP_PLUS:
1038 case OP_MINPLUS:
1039 case OP_POSPLUS:
1040 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf);
1041 try_next = FALSE;
1042 break;
1043
1044 case OP_EXACTI:
1045 tcode += IMM2_SIZE;
1046 /* Fall through */
1047 case OP_CHARI:
1048 case OP_PLUSI:
1049 case OP_MINPLUSI:
1050 case OP_POSPLUSI:
1051 (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf);
1052 try_next = FALSE;
1053 break;
1054
1055 /* Special spacing and line-terminating items. These recognize specific
1056 lists of characters. The difference between VSPACE and ANYNL is that the
1057 latter can match the two-character CRLF sequence, but that is not
1058 relevant for finding the first character, so their code here is
1059 identical. */
1060
1061 case OP_HSPACE:
1062 SET_BIT(CHAR_HT);
1063 SET_BIT(CHAR_SPACE);
1064 #ifdef SUPPORT_UTF
1065 if (utf)
1066 {
1067 #ifdef COMPILE_PCRE8
1068 SET_BIT(0xC2); /* For U+00A0 */
1069 SET_BIT(0xE1); /* For U+1680, U+180E */
1070 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1071 SET_BIT(0xE3); /* For U+3000 */
1072 #elif defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1073 SET_BIT(0xA0);
1074 SET_BIT(0xFF); /* For characters > 255 */
1075 #endif /* COMPILE_PCRE[8|16|32] */
1076 }
1077 else
1078 #endif /* SUPPORT_UTF */
1079 {
1080 #ifndef EBCDIC
1081 SET_BIT(0xA0);
1082 #endif /* Not EBCDIC */
1083 #if defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1084 SET_BIT(0xFF); /* For characters > 255 */
1085 #endif /* COMPILE_PCRE[16|32] */
1086 }
1087 try_next = FALSE;
1088 break;
1089
1090 case OP_ANYNL:
1091 case OP_VSPACE:
1092 SET_BIT(CHAR_LF);
1093 SET_BIT(CHAR_VT);
1094 SET_BIT(CHAR_FF);
1095 SET_BIT(CHAR_CR);
1096 #ifdef SUPPORT_UTF
1097 if (utf)
1098 {
1099 #ifdef COMPILE_PCRE8
1100 SET_BIT(0xC2); /* For U+0085 */
1101 SET_BIT(0xE2); /* For U+2028, U+2029 */
1102 #elif defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1103 SET_BIT(CHAR_NEL);
1104 SET_BIT(0xFF); /* For characters > 255 */
1105 #endif /* COMPILE_PCRE[8|16|32] */
1106 }
1107 else
1108 #endif /* SUPPORT_UTF */
1109 {
1110 SET_BIT(CHAR_NEL);
1111 #if defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1112 SET_BIT(0xFF); /* For characters > 255 */
1113 #endif
1114 }
1115 try_next = FALSE;
1116 break;
1117
1118 /* Single character types set the bits and stop. Note that if PCRE_UCP
1119 is set, we do not see these op codes because \d etc are converted to
1120 properties. Therefore, these apply in the case when only characters less
1121 than 256 are recognized to match the types. */
1122
1123 case OP_NOT_DIGIT:
1124 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1125 try_next = FALSE;
1126 break;
1127
1128 case OP_DIGIT:
1129 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1130 try_next = FALSE;
1131 break;
1132
1133 /* The cbit_space table has vertical tab as whitespace; we no longer
1134 have to play fancy tricks because Perl added VT to its whitespace at
1135 release 5.18. PCRE added it at release 8.34. */
1136
1137 case OP_NOT_WHITESPACE:
1138 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1139 try_next = FALSE;
1140 break;
1141
1142 case OP_WHITESPACE:
1143 set_type_bits(start_bits, cbit_space, table_limit, cd);
1144 try_next = FALSE;
1145 break;
1146
1147 case OP_NOT_WORDCHAR:
1148 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1149 try_next = FALSE;
1150 break;
1151
1152 case OP_WORDCHAR:
1153 set_type_bits(start_bits, cbit_word, table_limit, cd);
1154 try_next = FALSE;
1155 break;
1156
1157 /* One or more character type fudges the pointer and restarts, knowing
1158 it will hit a single character type and stop there. */
1159
1160 case OP_TYPEPLUS:
1161 case OP_TYPEMINPLUS:
1162 case OP_TYPEPOSPLUS:
1163 tcode++;
1164 break;
1165
1166 case OP_TYPEEXACT:
1167 tcode += 1 + IMM2_SIZE;
1168 break;
1169
1170 /* Zero or more repeats of character types set the bits and then
1171 try again. */
1172
1173 case OP_TYPEUPTO:
1174 case OP_TYPEMINUPTO:
1175 case OP_TYPEPOSUPTO:
1176 tcode += IMM2_SIZE; /* Fall through */
1177
1178 case OP_TYPESTAR:
1179 case OP_TYPEMINSTAR:
1180 case OP_TYPEPOSSTAR:
1181 case OP_TYPEQUERY:
1182 case OP_TYPEMINQUERY:
1183 case OP_TYPEPOSQUERY:
1184 switch(tcode[1])
1185 {
1186 default:
1187 case OP_ANY:
1188 case OP_ALLANY:
1189 return SSB_FAIL;
1190
1191 case OP_HSPACE:
1192 SET_BIT(CHAR_HT);
1193 SET_BIT(CHAR_SPACE);
1194 #ifdef SUPPORT_UTF
1195 if (utf)
1196 {
1197 #ifdef COMPILE_PCRE8
1198 SET_BIT(0xC2); /* For U+00A0 */
1199 SET_BIT(0xE1); /* For U+1680, U+180E */
1200 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1201 SET_BIT(0xE3); /* For U+3000 */
1202 #elif defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1203 SET_BIT(0xA0);
1204 SET_BIT(0xFF); /* For characters > 255 */
1205 #endif /* COMPILE_PCRE[8|16|32] */
1206 }
1207 else
1208 #endif /* SUPPORT_UTF */
1209 #ifndef EBCDIC
1210 SET_BIT(0xA0);
1211 #endif /* Not EBCDIC */
1212 break;
1213
1214 case OP_ANYNL:
1215 case OP_VSPACE:
1216 SET_BIT(CHAR_LF);
1217 SET_BIT(CHAR_VT);
1218 SET_BIT(CHAR_FF);
1219 SET_BIT(CHAR_CR);
1220 #ifdef SUPPORT_UTF
1221 if (utf)
1222 {
1223 #ifdef COMPILE_PCRE8
1224 SET_BIT(0xC2); /* For U+0085 */
1225 SET_BIT(0xE2); /* For U+2028, U+2029 */
1226 #elif defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1227 SET_BIT(CHAR_NEL);
1228 SET_BIT(0xFF); /* For characters > 255 */
1229 #endif /* COMPILE_PCRE16 */
1230 }
1231 else
1232 #endif /* SUPPORT_UTF */
1233 SET_BIT(CHAR_NEL);
1234 break;
1235
1236 case OP_NOT_DIGIT:
1237 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1238 break;
1239
1240 case OP_DIGIT:
1241 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1242 break;
1243
1244 /* The cbit_space table has vertical tab as whitespace; we no longer
1245 have to play fancy tricks because Perl added VT to its whitespace at
1246 release 5.18. PCRE added it at release 8.34. */
1247
1248 case OP_NOT_WHITESPACE:
1249 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1250 break;
1251
1252 case OP_WHITESPACE:
1253 set_type_bits(start_bits, cbit_space, table_limit, cd);
1254 break;
1255
1256 case OP_NOT_WORDCHAR:
1257 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1258 break;
1259
1260 case OP_WORDCHAR:
1261 set_type_bits(start_bits, cbit_word, table_limit, cd);
1262 break;
1263 }
1264
1265 tcode += 2;
1266 break;
1267
1268 /* Character class where all the information is in a bit map: set the
1269 bits and either carry on or not, according to the repeat count. If it was
1270 a negative class, and we are operating with UTF-8 characters, any byte
1271 with a value >= 0xc4 is a potentially valid starter because it starts a
1272 character with a value > 255. */
1273
1274 #if defined SUPPORT_UTF || !defined COMPILE_PCRE8
1275 case OP_XCLASS:
1276 if ((tcode[1 + LINK_SIZE] & XCL_HASPROP) != 0)
1277 return SSB_FAIL;
1278 /* All bits are set. */
1279 if ((tcode[1 + LINK_SIZE] & XCL_MAP) == 0 && (tcode[1 + LINK_SIZE] & XCL_NOT) != 0)
1280 return SSB_FAIL;
1281 #endif
1282 /* Fall through */
1283
1284 case OP_NCLASS:
1285 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
1286 if (utf)
1287 {
1288 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1289 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1290 }
1291 #endif
1292 #if defined COMPILE_PCRE16 || defined COMPILE_PCRE32
1293 SET_BIT(0xFF); /* For characters > 255 */
1294 #endif
1295 /* Fall through */
1296
1297 case OP_CLASS:
1298 {
1299 pcre_uint8 *map;
1300 #if defined SUPPORT_UTF || !defined COMPILE_PCRE8
1301 map = NULL;
1302 if (*tcode == OP_XCLASS)
1303 {
1304 if ((tcode[1 + LINK_SIZE] & XCL_MAP) != 0)
1305 map = (pcre_uint8 *)(tcode + 1 + LINK_SIZE + 1);
1306 tcode += GET(tcode, 1);
1307 }
1308 else
1309 #endif
1310 {
1311 tcode++;
1312 map = (pcre_uint8 *)tcode;
1313 tcode += 32 / sizeof(pcre_uchar);
1314 }
1315
1316 /* In UTF-8 mode, the bits in a bit map correspond to character
1317 values, not to byte values. However, the bit map we are constructing is
1318 for byte values. So we have to do a conversion for characters whose
1319 value is > 127. In fact, there are only two possible starting bytes for
1320 characters in the range 128 - 255. */
1321
1322 #if defined SUPPORT_UTF || !defined COMPILE_PCRE8
1323 if (map != NULL)
1324 #endif
1325 {
1326 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
1327 if (utf)
1328 {
1329 for (c = 0; c < 16; c++) start_bits[c] |= map[c];
1330 for (c = 128; c < 256; c++)
1331 {
1332 if ((map[c/8] && (1 << (c&7))) != 0)
1333 {
1334 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1335 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1336 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1337 }
1338 }
1339 }
1340 else
1341 #endif
1342 {
1343 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1344 for (c = 0; c < 32; c++) start_bits[c] |= map[c];
1345 }
1346 }
1347
1348 /* Advance past the bit map, and act on what follows. For a zero
1349 minimum repeat, continue; otherwise stop processing. */
1350
1351 switch (*tcode)
1352 {
1353 case OP_CRSTAR:
1354 case OP_CRMINSTAR:
1355 case OP_CRQUERY:
1356 case OP_CRMINQUERY:
1357 case OP_CRPOSSTAR:
1358 case OP_CRPOSQUERY:
1359 tcode++;
1360 break;
1361
1362 case OP_CRRANGE:
1363 case OP_CRMINRANGE:
1364 case OP_CRPOSRANGE:
1365 if (GET2(tcode, 1) == 0) tcode += 1 + 2 * IMM2_SIZE;
1366 else try_next = FALSE;
1367 break;
1368
1369 default:
1370 try_next = FALSE;
1371 break;
1372 }
1373 }
1374 break; /* End of bitmap class handling */
1375
1376 } /* End of switch */
1377 } /* End of try_next loop */
1378
1379 code += GET(code, 1); /* Advance to next branch */
1380 }
1381 while (*code == OP_ALT);
1382 return yield;
1383 }
1384
1385
1386
1387
1388
1389 /*************************************************
1390 * Study a compiled expression *
1391 *************************************************/
1392
1393 /* This function is handed a compiled expression that it must study to produce
1394 information that will speed up the matching. It returns a pcre[16]_extra block
1395 which then gets handed back to pcre_exec().
1396
1397 Arguments:
1398 re points to the compiled expression
1399 options contains option bits
1400 errorptr points to where to place error messages;
1401 set NULL unless error
1402
1403 Returns: pointer to a pcre[16]_extra block, with study_data filled in and
1404 the appropriate flags set;
1405 NULL on error or if no optimization possible
1406 */
1407
1408 #if defined COMPILE_PCRE8
1409 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1410 pcre_study(const pcre *external_re, int options, const char **errorptr)
1411 #elif defined COMPILE_PCRE16
1412 PCRE_EXP_DEFN pcre16_extra * PCRE_CALL_CONVENTION
1413 pcre16_study(const pcre16 *external_re, int options, const char **errorptr)
1414 #elif defined COMPILE_PCRE32
1415 PCRE_EXP_DEFN pcre32_extra * PCRE_CALL_CONVENTION
1416 pcre32_study(const pcre32 *external_re, int options, const char **errorptr)
1417 #endif
1418 {
1419 int min;
1420 BOOL bits_set = FALSE;
1421 pcre_uint8 start_bits[32];
1422 PUBL(extra) *extra = NULL;
1423 pcre_study_data *study;
1424 const pcre_uint8 *tables;
1425 pcre_uchar *code;
1426 compile_data compile_block;
1427 const REAL_PCRE *re = (const REAL_PCRE *)external_re;
1428
1429
1430 *errorptr = NULL;
1431
1432 if (re == NULL || re->magic_number != MAGIC_NUMBER)
1433 {
1434 *errorptr = "argument is not a compiled regular expression";
1435 return NULL;
1436 }
1437
1438 if ((re->flags & PCRE_MODE) == 0)
1439 {
1440 #if defined COMPILE_PCRE8
1441 *errorptr = "argument not compiled in 8 bit mode";
1442 #elif defined COMPILE_PCRE16
1443 *errorptr = "argument not compiled in 16 bit mode";
1444 #elif defined COMPILE_PCRE32
1445 *errorptr = "argument not compiled in 32 bit mode";
1446 #endif
1447 return NULL;
1448 }
1449
1450 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1451 {
1452 *errorptr = "unknown or incorrect option bit(s) set";
1453 return NULL;
1454 }
1455
1456 code = (pcre_uchar *)re + re->name_table_offset +
1457 (re->name_count * re->name_entry_size);
1458
1459 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1460 a multiline pattern that matches only at "line starts", there is no point in
1461 seeking a list of starting bytes. */
1462
1463 if ((re->options & PCRE_ANCHORED) == 0 &&
1464 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1465 {
1466 int rc;
1467
1468 /* Set the character tables in the block that is passed around */
1469
1470 tables = re->tables;
1471
1472 #if defined COMPILE_PCRE8
1473 if (tables == NULL)
1474 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1475 (void *)(&tables));
1476 #elif defined COMPILE_PCRE16
1477 if (tables == NULL)
1478 (void)pcre16_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1479 (void *)(&tables));
1480 #elif defined COMPILE_PCRE32
1481 if (tables == NULL)
1482 (void)pcre32_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1483 (void *)(&tables));
1484 #endif
1485
1486 compile_block.lcc = tables + lcc_offset;
1487 compile_block.fcc = tables + fcc_offset;
1488 compile_block.cbits = tables + cbits_offset;
1489 compile_block.ctypes = tables + ctypes_offset;
1490
1491 /* See if we can find a fixed set of initial characters for the pattern. */
1492
1493 memset(start_bits, 0, 32 * sizeof(pcre_uint8));
1494 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1495 &compile_block);
1496 bits_set = rc == SSB_DONE;
1497 if (rc == SSB_UNKNOWN)
1498 {
1499 *errorptr = "internal error: opcode not recognized";
1500 return NULL;
1501 }
1502 }
1503
1504 /* Find the minimum length of subject string. */
1505
1506 switch(min = find_minlength(re, code, code, re->options, 0))
1507 {
1508 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1509 case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1510 default: break;
1511 }
1512
1513 /* If a set of starting bytes has been identified, or if the minimum length is
1514 greater than zero, or if JIT optimization has been requested, or if
1515 PCRE_STUDY_EXTRA_NEEDED is set, get a pcre[16]_extra block and a
1516 pcre_study_data block. The study data is put in the latter, which is pointed to
1517 by the former, which may also get additional data set later by the calling
1518 program. At the moment, the size of pcre_study_data is fixed. We nevertheless
1519 save it in a field for returning via the pcre_fullinfo() function so that if it
1520 becomes variable in the future, we don't have to change that code. */
1521
1522 if (bits_set || min > 0 || (options & (
1523 #ifdef SUPPORT_JIT
1524 PCRE_STUDY_JIT_COMPILE | PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE |
1525 PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE |
1526 #endif
1527 PCRE_STUDY_EXTRA_NEEDED)) != 0)
1528 {
1529 extra = (PUBL(extra) *)(PUBL(malloc))
1530 (sizeof(PUBL(extra)) + sizeof(pcre_study_data));
1531 if (extra == NULL)
1532 {
1533 *errorptr = "failed to get memory";
1534 return NULL;
1535 }
1536
1537 study = (pcre_study_data *)((char *)extra + sizeof(PUBL(extra)));
1538 extra->flags = PCRE_EXTRA_STUDY_DATA;
1539 extra->study_data = study;
1540
1541 study->size = sizeof(pcre_study_data);
1542 study->flags = 0;
1543
1544 /* Set the start bits always, to avoid unset memory errors if the
1545 study data is written to a file, but set the flag only if any of the bits
1546 are set, to save time looking when none are. */
1547
1548 if (bits_set)
1549 {
1550 study->flags |= PCRE_STUDY_MAPPED;
1551 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1552 }
1553 else memset(study->start_bits, 0, 32 * sizeof(pcre_uint8));
1554
1555 #ifdef PCRE_DEBUG
1556 if (bits_set)
1557 {
1558 pcre_uint8 *ptr = start_bits;
1559 int i;
1560
1561 printf("Start bits:\n");
1562 for (i = 0; i < 32; i++)
1563 printf("%3d: %02x%s", i * 8, *ptr++, ((i + 1) & 0x7) != 0? " " : "\n");
1564 }
1565 #endif
1566
1567 /* Always set the minlength value in the block, because the JIT compiler
1568 makes use of it. However, don't set the bit unless the length is greater than
1569 zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1570 checking the zero case. */
1571
1572 if (min > 0)
1573 {
1574 study->flags |= PCRE_STUDY_MINLEN;
1575 study->minlength = min;
1576 }
1577 else study->minlength = 0;
1578
1579 /* If JIT support was compiled and requested, attempt the JIT compilation.
1580 If no starting bytes were found, and the minimum length is zero, and JIT
1581 compilation fails, abandon the extra block and return NULL, unless
1582 PCRE_STUDY_EXTRA_NEEDED is set. */
1583
1584 #ifdef SUPPORT_JIT
1585 extra->executable_jit = NULL;
1586 if ((options & PCRE_STUDY_JIT_COMPILE) != 0)
1587 PRIV(jit_compile)(re, extra, JIT_COMPILE);
1588 if ((options & PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE) != 0)
1589 PRIV(jit_compile)(re, extra, JIT_PARTIAL_SOFT_COMPILE);
1590 if ((options & PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE) != 0)
1591 PRIV(jit_compile)(re, extra, JIT_PARTIAL_HARD_COMPILE);
1592
1593 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0 &&
1594 (options & PCRE_STUDY_EXTRA_NEEDED) == 0)
1595 {
1596 #if defined COMPILE_PCRE8
1597 pcre_free_study(extra);
1598 #elif defined COMPILE_PCRE16
1599 pcre16_free_study(extra);
1600 #elif defined COMPILE_PCRE32
1601 pcre32_free_study(extra);
1602 #endif
1603 extra = NULL;
1604 }
1605 #endif
1606 }
1607
1608 return extra;
1609 }
1610
1611
1612 /*************************************************
1613 * Free the study data *
1614 *************************************************/
1615
1616 /* This function frees the memory that was obtained by pcre_study().
1617
1618 Argument: a pointer to the pcre[16]_extra block
1619 Returns: nothing
1620 */
1621
1622 #if defined COMPILE_PCRE8
1623 PCRE_EXP_DEFN void
1624 pcre_free_study(pcre_extra *extra)
1625 #elif defined COMPILE_PCRE16
1626 PCRE_EXP_DEFN void
1627 pcre16_free_study(pcre16_extra *extra)
1628 #elif defined COMPILE_PCRE32
1629 PCRE_EXP_DEFN void
1630 pcre32_free_study(pcre32_extra *extra)
1631 #endif
1632 {
1633 if (extra == NULL)
1634 return;
1635 #ifdef SUPPORT_JIT
1636 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1637 extra->executable_jit != NULL)
1638 PRIV(jit_free)(extra->executable_jit);
1639 #endif
1640 PUBL(free)(extra);
1641 }
1642
1643 /* End of pcre_study.c */

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