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Contents of /code/branches/pcre16/pcre_study.c

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Revision 770 - (show annotations)
Mon Nov 28 20:39:30 2011 UTC (7 years, 8 months ago) by zherczeg
File MIME type: text/plain
File size: 39733 byte(s)
Make character ranges 16 bit friendly
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) 1997-2010 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 code pointer to start of group (the bracket)
70 startcode pointer to start of the whole pattern
71 options the compiling options
72 int RECURSE depth
73
74 Returns: the minimum length
75 -1 if \C in UTF-8 mode or (*ACCEPT) was encountered
76 -2 internal error (missing capturing bracket)
77 -3 internal error (opcode not listed)
78 */
79
80 static int
81 find_minlength(const pcre_uchar *code, const pcre_uchar *startcode, int options,
82 int recurse_depth)
83 {
84 int length = -1;
85 BOOL utf8 = (options & PCRE_UTF8) != 0;
86 BOOL had_recurse = FALSE;
87 register int branchlength = 0;
88 register pcre_uchar *cc = (pcre_uchar *)code + 1 + LINK_SIZE;
89
90 if (*code == OP_CBRA || *code == OP_SCBRA ||
91 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += IMM2_SIZE;
92
93 /* Scan along the opcodes for this branch. If we get to the end of the
94 branch, check the length against that of the other branches. */
95
96 for (;;)
97 {
98 int d, min;
99 pcre_uchar *cs, *ce;
100 register int op = *cc;
101
102 switch (op)
103 {
104 case OP_COND:
105 case OP_SCOND:
106
107 /* If there is only one branch in a condition, the implied branch has zero
108 length, so we don't add anything. This covers the DEFINE "condition"
109 automatically. */
110
111 cs = cc + GET(cc, 1);
112 if (*cs != OP_ALT)
113 {
114 cc = cs + 1 + LINK_SIZE;
115 break;
116 }
117
118 /* Otherwise we can fall through and treat it the same as any other
119 subpattern. */
120
121 case OP_CBRA:
122 case OP_SCBRA:
123 case OP_BRA:
124 case OP_SBRA:
125 case OP_CBRAPOS:
126 case OP_SCBRAPOS:
127 case OP_BRAPOS:
128 case OP_SBRAPOS:
129 case OP_ONCE:
130 case OP_ONCE_NC:
131 d = find_minlength(cc, startcode, options, recurse_depth);
132 if (d < 0) return d;
133 branchlength += d;
134 do cc += GET(cc, 1); while (*cc == OP_ALT);
135 cc += 1 + LINK_SIZE;
136 break;
137
138 /* ACCEPT makes things far too complicated; we have to give up. */
139
140 case OP_ACCEPT:
141 case OP_ASSERT_ACCEPT:
142 return -1;
143
144 /* Reached end of a branch; if it's a ket it is the end of a nested
145 call. If it's ALT it is an alternation in a nested call. If it is END it's
146 the end of the outer call. All can be handled by the same code. If an
147 ACCEPT was previously encountered, use the length that was in force at that
148 time, and pass back the shortest ACCEPT length. */
149
150 case OP_ALT:
151 case OP_KET:
152 case OP_KETRMAX:
153 case OP_KETRMIN:
154 case OP_KETRPOS:
155 case OP_END:
156 if (length < 0 || (!had_recurse && branchlength < length))
157 length = branchlength;
158 if (op != OP_ALT) return length;
159 cc += 1 + LINK_SIZE;
160 branchlength = 0;
161 had_recurse = FALSE;
162 break;
163
164 /* Skip over assertive subpatterns */
165
166 case OP_ASSERT:
167 case OP_ASSERT_NOT:
168 case OP_ASSERTBACK:
169 case OP_ASSERTBACK_NOT:
170 do cc += GET(cc, 1); while (*cc == OP_ALT);
171 /* Fall through */
172
173 /* Skip over things that don't match chars */
174
175 case OP_REVERSE:
176 case OP_CREF:
177 case OP_NCREF:
178 case OP_RREF:
179 case OP_NRREF:
180 case OP_DEF:
181 case OP_CALLOUT:
182 case OP_SOD:
183 case OP_SOM:
184 case OP_EOD:
185 case OP_EODN:
186 case OP_CIRC:
187 case OP_CIRCM:
188 case OP_DOLL:
189 case OP_DOLLM:
190 case OP_NOT_WORD_BOUNDARY:
191 case OP_WORD_BOUNDARY:
192 cc += PRIV(OP_lengths)[*cc];
193 break;
194
195 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
196
197 case OP_BRAZERO:
198 case OP_BRAMINZERO:
199 case OP_BRAPOSZERO:
200 case OP_SKIPZERO:
201 cc += PRIV(OP_lengths)[*cc];
202 do cc += GET(cc, 1); while (*cc == OP_ALT);
203 cc += 1 + LINK_SIZE;
204 break;
205
206 /* Handle literal characters and + repetitions */
207
208 case OP_CHAR:
209 case OP_CHARI:
210 case OP_NOT:
211 case OP_NOTI:
212 case OP_PLUS:
213 case OP_PLUSI:
214 case OP_MINPLUS:
215 case OP_MINPLUSI:
216 case OP_POSPLUS:
217 case OP_POSPLUSI:
218 case OP_NOTPLUS:
219 case OP_NOTPLUSI:
220 case OP_NOTMINPLUS:
221 case OP_NOTMINPLUSI:
222 case OP_NOTPOSPLUS:
223 case OP_NOTPOSPLUSI:
224 branchlength++;
225 cc += 2;
226 #ifdef SUPPORT_UTF8
227 if (utf8 && cc[-1] >= 0xc0) cc += PRIV(utf8_table4)[cc[-1] & 0x3f];
228 #endif
229 break;
230
231 case OP_TYPEPLUS:
232 case OP_TYPEMINPLUS:
233 case OP_TYPEPOSPLUS:
234 branchlength++;
235 cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
236 break;
237
238 /* Handle exact repetitions. The count is already in characters, but we
239 need to skip over a multibyte character in UTF8 mode. */
240
241 case OP_EXACT:
242 case OP_EXACTI:
243 case OP_NOTEXACT:
244 case OP_NOTEXACTI:
245 branchlength += GET2(cc,1);
246 cc += 2 + IMM2_SIZE;
247 #ifdef SUPPORT_UTF8
248 if (utf8 && cc[-1] >= 0xc0) cc += PRIV(utf8_table4)[cc[-1] & 0x3f];
249 #endif
250 break;
251
252 case OP_TYPEEXACT:
253 branchlength += GET2(cc,1);
254 cc += 2 + IMM2_SIZE + ((cc[1 + IMM2_SIZE] == OP_PROP
255 || cc[1 + IMM2_SIZE] == OP_NOTPROP)? 2 : 0);
256 break;
257
258 /* Handle single-char non-literal matchers */
259
260 case OP_PROP:
261 case OP_NOTPROP:
262 cc += 2;
263 /* Fall through */
264
265 case OP_NOT_DIGIT:
266 case OP_DIGIT:
267 case OP_NOT_WHITESPACE:
268 case OP_WHITESPACE:
269 case OP_NOT_WORDCHAR:
270 case OP_WORDCHAR:
271 case OP_ANY:
272 case OP_ALLANY:
273 case OP_EXTUNI:
274 case OP_HSPACE:
275 case OP_NOT_HSPACE:
276 case OP_VSPACE:
277 case OP_NOT_VSPACE:
278 branchlength++;
279 cc++;
280 break;
281
282 /* "Any newline" might match two characters, but it also might match just
283 one. */
284
285 case OP_ANYNL:
286 branchlength += 1;
287 cc++;
288 break;
289
290 /* The single-byte matcher means we can't proceed in UTF-8 mode. (In
291 non-UTF-8 mode \C will actually be turned into OP_ALLANY, so won't ever
292 appear, but leave the code, just in case.) */
293
294 case OP_ANYBYTE:
295 #ifdef SUPPORT_UTF8
296 if (utf8) return -1;
297 #endif
298 branchlength++;
299 cc++;
300 break;
301
302 /* For repeated character types, we have to test for \p and \P, which have
303 an extra two bytes of parameters. */
304
305 case OP_TYPESTAR:
306 case OP_TYPEMINSTAR:
307 case OP_TYPEQUERY:
308 case OP_TYPEMINQUERY:
309 case OP_TYPEPOSSTAR:
310 case OP_TYPEPOSQUERY:
311 if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
312 cc += PRIV(OP_lengths)[op];
313 break;
314
315 case OP_TYPEUPTO:
316 case OP_TYPEMINUPTO:
317 case OP_TYPEPOSUPTO:
318 if (cc[1 + IMM2_SIZE] == OP_PROP
319 || cc[1 + IMM2_SIZE] == OP_NOTPROP) cc += 2;
320 cc += PRIV(OP_lengths)[op];
321 break;
322
323 /* Check a class for variable quantification */
324
325 #if defined SUPPORT_UTF8 || !defined COMPILE_PCRE8
326 case OP_XCLASS:
327 cc += GET(cc, 1) - PRIV(OP_lengths)[OP_CLASS];
328 /* Fall through */
329 #endif
330
331 case OP_CLASS:
332 case OP_NCLASS:
333 cc += PRIV(OP_lengths)[OP_CLASS];
334
335 switch (*cc)
336 {
337 case OP_CRPLUS:
338 case OP_CRMINPLUS:
339 branchlength++;
340 /* Fall through */
341
342 case OP_CRSTAR:
343 case OP_CRMINSTAR:
344 case OP_CRQUERY:
345 case OP_CRMINQUERY:
346 cc++;
347 break;
348
349 case OP_CRRANGE:
350 case OP_CRMINRANGE:
351 branchlength += GET2(cc,1);
352 cc += 1 + 2 * IMM2_SIZE;
353 break;
354
355 default:
356 branchlength++;
357 break;
358 }
359 break;
360
361 /* Backreferences and subroutine calls are treated in the same way: we find
362 the minimum length for the subpattern. A recursion, however, causes an
363 a flag to be set that causes the length of this branch to be ignored. The
364 logic is that a recursion can only make sense if there is another
365 alternation that stops the recursing. That will provide the minimum length
366 (when no recursion happens). A backreference within the group that it is
367 referencing behaves in the same way.
368
369 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
370 matches an empty string (by default it causes a matching failure), so in
371 that case we must set the minimum length to zero. */
372
373 case OP_REF:
374 case OP_REFI:
375 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
376 {
377 ce = cs = (pcre_uchar *)PRIV(find_bracket)(startcode, utf8, GET2(cc, 1));
378 if (cs == NULL) return -2;
379 do ce += GET(ce, 1); while (*ce == OP_ALT);
380 if (cc > cs && cc < ce)
381 {
382 d = 0;
383 had_recurse = TRUE;
384 }
385 else
386 {
387 d = find_minlength(cs, startcode, options, recurse_depth);
388 }
389 }
390 else d = 0;
391 cc += 1 + IMM2_SIZE;
392
393 /* Handle repeated back references */
394
395 switch (*cc)
396 {
397 case OP_CRSTAR:
398 case OP_CRMINSTAR:
399 case OP_CRQUERY:
400 case OP_CRMINQUERY:
401 min = 0;
402 cc++;
403 break;
404
405 case OP_CRPLUS:
406 case OP_CRMINPLUS:
407 min = 1;
408 cc++;
409 break;
410
411 case OP_CRRANGE:
412 case OP_CRMINRANGE:
413 min = GET2(cc, 1);
414 cc += 1 + 2 * IMM2_SIZE;
415 break;
416
417 default:
418 min = 1;
419 break;
420 }
421
422 branchlength += min * d;
423 break;
424
425 /* We can easily detect direct recursion, but not mutual recursion. This is
426 caught by a recursion depth count. */
427
428 case OP_RECURSE:
429 cs = ce = (pcre_uchar *)startcode + GET(cc, 1);
430 do ce += GET(ce, 1); while (*ce == OP_ALT);
431 if ((cc > cs && cc < ce) || recurse_depth > 10)
432 had_recurse = TRUE;
433 else
434 {
435 branchlength += find_minlength(cs, startcode, options, recurse_depth + 1);
436 }
437 cc += 1 + LINK_SIZE;
438 break;
439
440 /* Anything else does not or need not match a character. We can get the
441 item's length from the table, but for those that can match zero occurrences
442 of a character, we must take special action for UTF-8 characters. As it
443 happens, the "NOT" versions of these opcodes are used at present only for
444 ASCII characters, so they could be omitted from this list. However, in
445 future that may change, so we include them here so as not to leave a
446 gotcha for a future maintainer. */
447
448 case OP_UPTO:
449 case OP_UPTOI:
450 case OP_NOTUPTO:
451 case OP_NOTUPTOI:
452 case OP_MINUPTO:
453 case OP_MINUPTOI:
454 case OP_NOTMINUPTO:
455 case OP_NOTMINUPTOI:
456 case OP_POSUPTO:
457 case OP_POSUPTOI:
458 case OP_NOTPOSUPTO:
459 case OP_NOTPOSUPTOI:
460
461 case OP_STAR:
462 case OP_STARI:
463 case OP_NOTSTAR:
464 case OP_NOTSTARI:
465 case OP_MINSTAR:
466 case OP_MINSTARI:
467 case OP_NOTMINSTAR:
468 case OP_NOTMINSTARI:
469 case OP_POSSTAR:
470 case OP_POSSTARI:
471 case OP_NOTPOSSTAR:
472 case OP_NOTPOSSTARI:
473
474 case OP_QUERY:
475 case OP_QUERYI:
476 case OP_NOTQUERY:
477 case OP_NOTQUERYI:
478 case OP_MINQUERY:
479 case OP_MINQUERYI:
480 case OP_NOTMINQUERY:
481 case OP_NOTMINQUERYI:
482 case OP_POSQUERY:
483 case OP_POSQUERYI:
484 case OP_NOTPOSQUERY:
485 case OP_NOTPOSQUERYI:
486
487 cc += PRIV(OP_lengths)[op];
488 #ifdef SUPPORT_UTF8
489 if (utf8 && cc[-1] >= 0xc0) cc += PRIV(utf8_table4)[cc[-1] & 0x3f];
490 #endif
491 break;
492
493 /* Skip these, but we need to add in the name length. */
494
495 case OP_MARK:
496 case OP_PRUNE_ARG:
497 case OP_SKIP_ARG:
498 case OP_THEN_ARG:
499 cc += PRIV(OP_lengths)[op] + cc[1];
500 break;
501
502 /* The remaining opcodes are just skipped over. */
503
504 case OP_CLOSE:
505 case OP_COMMIT:
506 case OP_FAIL:
507 case OP_PRUNE:
508 case OP_SET_SOM:
509 case OP_SKIP:
510 case OP_THEN:
511 cc += PRIV(OP_lengths)[op];
512 break;
513
514 /* This should not occur: we list all opcodes explicitly so that when
515 new ones get added they are properly considered. */
516
517 default:
518 return -3;
519 }
520 }
521 /* Control never gets here */
522 }
523
524
525
526 /*************************************************
527 * Set a bit and maybe its alternate case *
528 *************************************************/
529
530 /* Given a character, set its first byte's bit in the table, and also the
531 corresponding bit for the other version of a letter if we are caseless. In
532 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
533 when Unicode property support is available.
534
535 Arguments:
536 start_bits points to the bit map
537 p points to the character
538 caseless the caseless flag
539 cd the block with char table pointers
540 utf8 TRUE for UTF-8 mode
541
542 Returns: pointer after the character
543 */
544
545 static const pcre_uchar *
546 set_table_bit(pcre_uint8 *start_bits, const pcre_uchar *p, BOOL caseless,
547 compile_data *cd, BOOL utf8)
548 {
549 unsigned int c = *p;
550
551 SET_BIT(c);
552
553 #ifdef SUPPORT_UTF8
554 if (utf8 && c > 127)
555 {
556 GETCHARINC(c, p);
557 #ifdef SUPPORT_UCP
558 if (caseless)
559 {
560 pcre_uint8 buff[8];
561 c = UCD_OTHERCASE(c);
562 (void)PRIV(ord2utf8)(c, buff);
563 SET_BIT(buff[0]);
564 }
565 #endif
566 return p;
567 }
568 #endif
569
570 /* Not UTF-8 mode, or character is less than 127. */
571
572 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
573 return p + 1;
574 }
575
576
577
578 /*************************************************
579 * Set bits for a positive character type *
580 *************************************************/
581
582 /* This function sets starting bits for a character type. In UTF-8 mode, we can
583 only do a direct setting for bytes less than 128, as otherwise there can be
584 confusion with bytes in the middle of UTF-8 characters. In a "traditional"
585 environment, the tables will only recognize ASCII characters anyway, but in at
586 least one Windows environment, some higher bytes bits were set in the tables.
587 So we deal with that case by considering the UTF-8 encoding.
588
589 Arguments:
590 start_bits the starting bitmap
591 cbit type the type of character wanted
592 table_limit 32 for non-UTF-8; 16 for UTF-8
593 cd the block with char table pointers
594
595 Returns: nothing
596 */
597
598 static void
599 set_type_bits(pcre_uint8 *start_bits, int cbit_type, int table_limit,
600 compile_data *cd)
601 {
602 register int c;
603 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
604 #ifdef SUPPORT_UTF8
605 if (table_limit == 32) return;
606 for (c = 128; c < 256; c++)
607 {
608 if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
609 {
610 pcre_uint8 buff[8];
611 (void)PRIV(ord2utf8)(c, buff);
612 SET_BIT(buff[0]);
613 }
614 }
615 #endif
616 }
617
618
619 /*************************************************
620 * Set bits for a negative character type *
621 *************************************************/
622
623 /* This function sets starting bits for a negative character type such as \D.
624 In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
625 otherwise there can be confusion with bytes in the middle of UTF-8 characters.
626 Unlike in the positive case, where we can set appropriate starting bits for
627 specific high-valued UTF-8 characters, in this case we have to set the bits for
628 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
629 0xc0 (192) for simplicity.
630
631 Arguments:
632 start_bits the starting bitmap
633 cbit type the type of character wanted
634 table_limit 32 for non-UTF-8; 16 for UTF-8
635 cd the block with char table pointers
636
637 Returns: nothing
638 */
639
640 static void
641 set_nottype_bits(pcre_uint8 *start_bits, int cbit_type, int table_limit,
642 compile_data *cd)
643 {
644 register int c;
645 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
646 if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
647 }
648
649
650
651 /*************************************************
652 * Create bitmap of starting bytes *
653 *************************************************/
654
655 /* This function scans a compiled unanchored expression recursively and
656 attempts to build a bitmap of the set of possible starting bytes. As time goes
657 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
658 useful for parenthesized groups in patterns such as (a*)b where the group
659 provides some optional starting bytes but scanning must continue at the outer
660 level to find at least one mandatory byte. At the outermost level, this
661 function fails unless the result is SSB_DONE.
662
663 Arguments:
664 code points to an expression
665 start_bits points to a 32-byte table, initialized to 0
666 utf8 TRUE if in UTF-8 mode
667 cd the block with char table pointers
668
669 Returns: SSB_FAIL => Failed to find any starting bytes
670 SSB_DONE => Found mandatory starting bytes
671 SSB_CONTINUE => Found optional starting bytes
672 SSB_UNKNOWN => Hit an unrecognized opcode
673 */
674
675 static int
676 set_start_bits(const pcre_uchar *code, pcre_uint8 *start_bits, BOOL utf8,
677 compile_data *cd)
678 {
679 register int c;
680 int yield = SSB_DONE;
681 int table_limit = utf8? 16:32;
682
683 #if 0
684 /* ========================================================================= */
685 /* The following comment and code was inserted in January 1999. In May 2006,
686 when it was observed to cause compiler warnings about unused values, I took it
687 out again. If anybody is still using OS/2, they will have to put it back
688 manually. */
689
690 /* This next statement and the later reference to dummy are here in order to
691 trick the optimizer of the IBM C compiler for OS/2 into generating correct
692 code. Apparently IBM isn't going to fix the problem, and we would rather not
693 disable optimization (in this module it actually makes a big difference, and
694 the pcre module can use all the optimization it can get). */
695
696 volatile int dummy;
697 /* ========================================================================= */
698 #endif
699
700 do
701 {
702 BOOL try_next = TRUE;
703 const pcre_uchar *tcode = code + 1 + LINK_SIZE;
704
705 if (*code == OP_CBRA || *code == OP_SCBRA ||
706 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += IMM2_SIZE;
707
708 while (try_next) /* Loop for items in this branch */
709 {
710 int rc;
711
712 switch(*tcode)
713 {
714 /* If we reach something we don't understand, it means a new opcode has
715 been created that hasn't been added to this code. Hopefully this problem
716 will be discovered during testing. */
717
718 default:
719 return SSB_UNKNOWN;
720
721 /* Fail for a valid opcode that implies no starting bits. */
722
723 case OP_ACCEPT:
724 case OP_ASSERT_ACCEPT:
725 case OP_ALLANY:
726 case OP_ANY:
727 case OP_ANYBYTE:
728 case OP_CIRC:
729 case OP_CIRCM:
730 case OP_CLOSE:
731 case OP_COMMIT:
732 case OP_COND:
733 case OP_CREF:
734 case OP_DEF:
735 case OP_DOLL:
736 case OP_DOLLM:
737 case OP_END:
738 case OP_EOD:
739 case OP_EODN:
740 case OP_EXTUNI:
741 case OP_FAIL:
742 case OP_MARK:
743 case OP_NCREF:
744 case OP_NOT:
745 case OP_NOTEXACT:
746 case OP_NOTEXACTI:
747 case OP_NOTI:
748 case OP_NOTMINPLUS:
749 case OP_NOTMINPLUSI:
750 case OP_NOTMINQUERY:
751 case OP_NOTMINQUERYI:
752 case OP_NOTMINSTAR:
753 case OP_NOTMINSTARI:
754 case OP_NOTMINUPTO:
755 case OP_NOTMINUPTOI:
756 case OP_NOTPLUS:
757 case OP_NOTPLUSI:
758 case OP_NOTPOSPLUS:
759 case OP_NOTPOSPLUSI:
760 case OP_NOTPOSQUERY:
761 case OP_NOTPOSQUERYI:
762 case OP_NOTPOSSTAR:
763 case OP_NOTPOSSTARI:
764 case OP_NOTPOSUPTO:
765 case OP_NOTPOSUPTOI:
766 case OP_NOTPROP:
767 case OP_NOTQUERY:
768 case OP_NOTQUERYI:
769 case OP_NOTSTAR:
770 case OP_NOTSTARI:
771 case OP_NOTUPTO:
772 case OP_NOTUPTOI:
773 case OP_NOT_HSPACE:
774 case OP_NOT_VSPACE:
775 case OP_NRREF:
776 case OP_PROP:
777 case OP_PRUNE:
778 case OP_PRUNE_ARG:
779 case OP_RECURSE:
780 case OP_REF:
781 case OP_REFI:
782 case OP_REVERSE:
783 case OP_RREF:
784 case OP_SCOND:
785 case OP_SET_SOM:
786 case OP_SKIP:
787 case OP_SKIP_ARG:
788 case OP_SOD:
789 case OP_SOM:
790 case OP_THEN:
791 case OP_THEN_ARG:
792 #if defined SUPPORT_UTF8 || !defined COMPILE_PCRE8
793 case OP_XCLASS:
794 #endif
795 return SSB_FAIL;
796
797 /* We can ignore word boundary tests. */
798
799 case OP_WORD_BOUNDARY:
800 case OP_NOT_WORD_BOUNDARY:
801 tcode++;
802 break;
803
804 /* If we hit a bracket or a positive lookahead assertion, recurse to set
805 bits from within the subpattern. If it can't find anything, we have to
806 give up. If it finds some mandatory character(s), we are done for this
807 branch. Otherwise, carry on scanning after the subpattern. */
808
809 case OP_BRA:
810 case OP_SBRA:
811 case OP_CBRA:
812 case OP_SCBRA:
813 case OP_BRAPOS:
814 case OP_SBRAPOS:
815 case OP_CBRAPOS:
816 case OP_SCBRAPOS:
817 case OP_ONCE:
818 case OP_ONCE_NC:
819 case OP_ASSERT:
820 rc = set_start_bits(tcode, start_bits, utf8, cd);
821 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
822 if (rc == SSB_DONE) try_next = FALSE; else
823 {
824 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
825 tcode += 1 + LINK_SIZE;
826 }
827 break;
828
829 /* If we hit ALT or KET, it means we haven't found anything mandatory in
830 this branch, though we might have found something optional. For ALT, we
831 continue with the next alternative, but we have to arrange that the final
832 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
833 return SSB_CONTINUE: if this is the top level, that indicates failure,
834 but after a nested subpattern, it causes scanning to continue. */
835
836 case OP_ALT:
837 yield = SSB_CONTINUE;
838 try_next = FALSE;
839 break;
840
841 case OP_KET:
842 case OP_KETRMAX:
843 case OP_KETRMIN:
844 case OP_KETRPOS:
845 return SSB_CONTINUE;
846
847 /* Skip over callout */
848
849 case OP_CALLOUT:
850 tcode += 2 + 2*LINK_SIZE;
851 break;
852
853 /* Skip over lookbehind and negative lookahead assertions */
854
855 case OP_ASSERT_NOT:
856 case OP_ASSERTBACK:
857 case OP_ASSERTBACK_NOT:
858 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
859 tcode += 1 + LINK_SIZE;
860 break;
861
862 /* BRAZERO does the bracket, but carries on. */
863
864 case OP_BRAZERO:
865 case OP_BRAMINZERO:
866 case OP_BRAPOSZERO:
867 rc = set_start_bits(++tcode, start_bits, utf8, cd);
868 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
869 /* =========================================================================
870 See the comment at the head of this function concerning the next line,
871 which was an old fudge for the benefit of OS/2.
872 dummy = 1;
873 ========================================================================= */
874 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
875 tcode += 1 + LINK_SIZE;
876 break;
877
878 /* SKIPZERO skips the bracket. */
879
880 case OP_SKIPZERO:
881 tcode++;
882 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
883 tcode += 1 + LINK_SIZE;
884 break;
885
886 /* Single-char * or ? sets the bit and tries the next item */
887
888 case OP_STAR:
889 case OP_MINSTAR:
890 case OP_POSSTAR:
891 case OP_QUERY:
892 case OP_MINQUERY:
893 case OP_POSQUERY:
894 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
895 break;
896
897 case OP_STARI:
898 case OP_MINSTARI:
899 case OP_POSSTARI:
900 case OP_QUERYI:
901 case OP_MINQUERYI:
902 case OP_POSQUERYI:
903 tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
904 break;
905
906 /* Single-char upto sets the bit and tries the next */
907
908 case OP_UPTO:
909 case OP_MINUPTO:
910 case OP_POSUPTO:
911 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, FALSE, cd, utf8);
912 break;
913
914 case OP_UPTOI:
915 case OP_MINUPTOI:
916 case OP_POSUPTOI:
917 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, TRUE, cd, utf8);
918 break;
919
920 /* At least one single char sets the bit and stops */
921
922 case OP_EXACT:
923 tcode += IMM2_SIZE;
924 /* Fall through */
925 case OP_CHAR:
926 case OP_PLUS:
927 case OP_MINPLUS:
928 case OP_POSPLUS:
929 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
930 try_next = FALSE;
931 break;
932
933 case OP_EXACTI:
934 tcode += IMM2_SIZE;
935 /* Fall through */
936 case OP_CHARI:
937 case OP_PLUSI:
938 case OP_MINPLUSI:
939 case OP_POSPLUSI:
940 (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
941 try_next = FALSE;
942 break;
943
944 /* Special spacing and line-terminating items. These recognize specific
945 lists of characters. The difference between VSPACE and ANYNL is that the
946 latter can match the two-character CRLF sequence, but that is not
947 relevant for finding the first character, so their code here is
948 identical. */
949
950 case OP_HSPACE:
951 SET_BIT(0x09);
952 SET_BIT(0x20);
953 if (utf8)
954 {
955 SET_BIT(0xC2); /* For U+00A0 */
956 SET_BIT(0xE1); /* For U+1680, U+180E */
957 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
958 SET_BIT(0xE3); /* For U+3000 */
959 }
960 else SET_BIT(0xA0);
961 try_next = FALSE;
962 break;
963
964 case OP_ANYNL:
965 case OP_VSPACE:
966 SET_BIT(0x0A);
967 SET_BIT(0x0B);
968 SET_BIT(0x0C);
969 SET_BIT(0x0D);
970 if (utf8)
971 {
972 SET_BIT(0xC2); /* For U+0085 */
973 SET_BIT(0xE2); /* For U+2028, U+2029 */
974 }
975 else SET_BIT(0x85);
976 try_next = FALSE;
977 break;
978
979 /* Single character types set the bits and stop. Note that if PCRE_UCP
980 is set, we do not see these op codes because \d etc are converted to
981 properties. Therefore, these apply in the case when only characters less
982 than 256 are recognized to match the types. */
983
984 case OP_NOT_DIGIT:
985 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
986 try_next = FALSE;
987 break;
988
989 case OP_DIGIT:
990 set_type_bits(start_bits, cbit_digit, table_limit, cd);
991 try_next = FALSE;
992 break;
993
994 /* The cbit_space table has vertical tab as whitespace; we have to
995 ensure it is set as not whitespace. */
996
997 case OP_NOT_WHITESPACE:
998 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
999 start_bits[1] |= 0x08;
1000 try_next = FALSE;
1001 break;
1002
1003 /* The cbit_space table has vertical tab as whitespace; we have to
1004 not set it from the table. */
1005
1006 case OP_WHITESPACE:
1007 c = start_bits[1]; /* Save in case it was already set */
1008 set_type_bits(start_bits, cbit_space, table_limit, cd);
1009 start_bits[1] = (start_bits[1] & ~0x08) | c;
1010 try_next = FALSE;
1011 break;
1012
1013 case OP_NOT_WORDCHAR:
1014 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1015 try_next = FALSE;
1016 break;
1017
1018 case OP_WORDCHAR:
1019 set_type_bits(start_bits, cbit_word, table_limit, cd);
1020 try_next = FALSE;
1021 break;
1022
1023 /* One or more character type fudges the pointer and restarts, knowing
1024 it will hit a single character type and stop there. */
1025
1026 case OP_TYPEPLUS:
1027 case OP_TYPEMINPLUS:
1028 case OP_TYPEPOSPLUS:
1029 tcode++;
1030 break;
1031
1032 case OP_TYPEEXACT:
1033 tcode += 1 + IMM2_SIZE;
1034 break;
1035
1036 /* Zero or more repeats of character types set the bits and then
1037 try again. */
1038
1039 case OP_TYPEUPTO:
1040 case OP_TYPEMINUPTO:
1041 case OP_TYPEPOSUPTO:
1042 tcode += IMM2_SIZE; /* Fall through */
1043
1044 case OP_TYPESTAR:
1045 case OP_TYPEMINSTAR:
1046 case OP_TYPEPOSSTAR:
1047 case OP_TYPEQUERY:
1048 case OP_TYPEMINQUERY:
1049 case OP_TYPEPOSQUERY:
1050 switch(tcode[1])
1051 {
1052 default:
1053 case OP_ANY:
1054 case OP_ALLANY:
1055 return SSB_FAIL;
1056
1057 case OP_HSPACE:
1058 SET_BIT(0x09);
1059 SET_BIT(0x20);
1060 if (utf8)
1061 {
1062 SET_BIT(0xC2); /* For U+00A0 */
1063 SET_BIT(0xE1); /* For U+1680, U+180E */
1064 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1065 SET_BIT(0xE3); /* For U+3000 */
1066 }
1067 else SET_BIT(0xA0);
1068 break;
1069
1070 case OP_ANYNL:
1071 case OP_VSPACE:
1072 SET_BIT(0x0A);
1073 SET_BIT(0x0B);
1074 SET_BIT(0x0C);
1075 SET_BIT(0x0D);
1076 if (utf8)
1077 {
1078 SET_BIT(0xC2); /* For U+0085 */
1079 SET_BIT(0xE2); /* For U+2028, U+2029 */
1080 }
1081 else SET_BIT(0x85);
1082 break;
1083
1084 case OP_NOT_DIGIT:
1085 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1086 break;
1087
1088 case OP_DIGIT:
1089 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1090 break;
1091
1092 /* The cbit_space table has vertical tab as whitespace; we have to
1093 ensure it gets set as not whitespace. */
1094
1095 case OP_NOT_WHITESPACE:
1096 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1097 start_bits[1] |= 0x08;
1098 break;
1099
1100 /* The cbit_space table has vertical tab as whitespace; we have to
1101 avoid setting it. */
1102
1103 case OP_WHITESPACE:
1104 c = start_bits[1]; /* Save in case it was already set */
1105 set_type_bits(start_bits, cbit_space, table_limit, cd);
1106 start_bits[1] = (start_bits[1] & ~0x08) | c;
1107 break;
1108
1109 case OP_NOT_WORDCHAR:
1110 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1111 break;
1112
1113 case OP_WORDCHAR:
1114 set_type_bits(start_bits, cbit_word, table_limit, cd);
1115 break;
1116 }
1117
1118 tcode += 2;
1119 break;
1120
1121 /* Character class where all the information is in a bit map: set the
1122 bits and either carry on or not, according to the repeat count. If it was
1123 a negative class, and we are operating with UTF-8 characters, any byte
1124 with a value >= 0xc4 is a potentially valid starter because it starts a
1125 character with a value > 255. */
1126
1127 case OP_NCLASS:
1128 #ifdef SUPPORT_UTF8
1129 if (utf8)
1130 {
1131 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1132 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1133 }
1134 #endif
1135 /* Fall through */
1136
1137 case OP_CLASS:
1138 {
1139 pcre_uint8 *map;
1140 tcode++;
1141 map = (pcre_uint8 *)tcode;
1142
1143 /* In UTF-8 mode, the bits in a bit map correspond to character
1144 values, not to byte values. However, the bit map we are constructing is
1145 for byte values. So we have to do a conversion for characters whose
1146 value is > 127. In fact, there are only two possible starting bytes for
1147 characters in the range 128 - 255. */
1148
1149 #ifdef SUPPORT_UTF8
1150 if (utf8)
1151 {
1152 for (c = 0; c < 16; c++) start_bits[c] |= map[c];
1153 for (c = 128; c < 256; c++)
1154 {
1155 if ((map[c/8] && (1 << (c&7))) != 0)
1156 {
1157 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1158 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1159 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1160 }
1161 }
1162 }
1163
1164 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1165
1166 else
1167 #endif
1168 {
1169 for (c = 0; c < 32; c++) start_bits[c] |= map[c];
1170 }
1171
1172 /* Advance past the bit map, and act on what follows. For a zero
1173 minimum repeat, continue; otherwise stop processing. */
1174
1175 tcode += 32 / sizeof(pcre_uchar);
1176 switch (*tcode)
1177 {
1178 case OP_CRSTAR:
1179 case OP_CRMINSTAR:
1180 case OP_CRQUERY:
1181 case OP_CRMINQUERY:
1182 tcode++;
1183 break;
1184
1185 case OP_CRRANGE:
1186 case OP_CRMINRANGE:
1187 if (GET2(tcode, 1) == 0) tcode += 1 + 2 * IMM2_SIZE;
1188 else try_next = FALSE;
1189 break;
1190
1191 default:
1192 try_next = FALSE;
1193 break;
1194 }
1195 }
1196 break; /* End of bitmap class handling */
1197
1198 } /* End of switch */
1199 } /* End of try_next loop */
1200
1201 code += GET(code, 1); /* Advance to next branch */
1202 }
1203 while (*code == OP_ALT);
1204 return yield;
1205 }
1206
1207
1208
1209
1210
1211 /*************************************************
1212 * Study a compiled expression *
1213 *************************************************/
1214
1215 /* This function is handed a compiled expression that it must study to produce
1216 information that will speed up the matching. It returns a pcre_extra block
1217 which then gets handed back to pcre_exec().
1218
1219 Arguments:
1220 re points to the compiled expression
1221 options contains option bits
1222 errorptr points to where to place error messages;
1223 set NULL unless error
1224
1225 Returns: pointer to a pcre_extra block, with study_data filled in and the
1226 appropriate flags set;
1227 NULL on error or if no optimization possible
1228 */
1229
1230 #ifdef COMPILE_PCRE8
1231 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1232 pcre_study(const pcre *external_re, int options, const char **errorptr)
1233 #else
1234 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1235 pcre16_study(const pcre *external_re, int options, const char **errorptr)
1236 #endif
1237 {
1238 int min;
1239 BOOL bits_set = FALSE;
1240 pcre_uint8 start_bits[32];
1241 pcre_extra *extra = NULL;
1242 pcre_study_data *study;
1243 const pcre_uint8 *tables;
1244 pcre_uchar *code;
1245 compile_data compile_block;
1246 const real_pcre *re = (const real_pcre *)external_re;
1247
1248 *errorptr = NULL;
1249
1250 if (re == NULL || re->magic_number != MAGIC_NUMBER)
1251 {
1252 *errorptr = "argument is not a compiled regular expression";
1253 return NULL;
1254 }
1255
1256 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1257 {
1258 *errorptr = "unknown or incorrect option bit(s) set";
1259 return NULL;
1260 }
1261
1262 code = (pcre_uchar *)re + re->name_table_offset +
1263 (re->name_count * re->name_entry_size);
1264
1265 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1266 a multiline pattern that matches only at "line starts", there is no point in
1267 seeking a list of starting bytes. */
1268
1269 if ((re->options & PCRE_ANCHORED) == 0 &&
1270 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1271 {
1272 int rc;
1273
1274 /* Set the character tables in the block that is passed around */
1275
1276 tables = re->tables;
1277 if (tables == NULL)
1278 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1279 (void *)(&tables));
1280
1281 compile_block.lcc = tables + lcc_offset;
1282 compile_block.fcc = tables + fcc_offset;
1283 compile_block.cbits = tables + cbits_offset;
1284 compile_block.ctypes = tables + ctypes_offset;
1285
1286 /* See if we can find a fixed set of initial characters for the pattern. */
1287
1288 memset(start_bits, 0, 32 * sizeof(pcre_uint8));
1289 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1290 &compile_block);
1291 bits_set = rc == SSB_DONE;
1292 if (rc == SSB_UNKNOWN)
1293 {
1294 *errorptr = "internal error: opcode not recognized";
1295 return NULL;
1296 }
1297 }
1298
1299 /* Find the minimum length of subject string. */
1300
1301 switch(min = find_minlength(code, code, re->options, 0))
1302 {
1303 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1304 case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1305 default: break;
1306 }
1307
1308 /* If a set of starting bytes has been identified, or if the minimum length is
1309 greater than zero, or if JIT optimization has been requested, get a pcre_extra
1310 block and a pcre_study_data block. The study data is put in the latter, which
1311 is pointed to by the former, which may also get additional data set later by
1312 the calling program. At the moment, the size of pcre_study_data is fixed. We
1313 nevertheless save it in a field for returning via the pcre_fullinfo() function
1314 so that if it becomes variable in the future, we don't have to change that
1315 code. */
1316
1317 if (bits_set || min > 0
1318 #ifdef SUPPORT_JIT
1319 || (options & PCRE_STUDY_JIT_COMPILE) != 0
1320 #endif
1321 )
1322 {
1323 extra = (pcre_extra *)(pcre_malloc)
1324 (sizeof(pcre_extra) + sizeof(pcre_study_data));
1325 if (extra == NULL)
1326 {
1327 *errorptr = "failed to get memory";
1328 return NULL;
1329 }
1330
1331 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1332 extra->flags = PCRE_EXTRA_STUDY_DATA;
1333 extra->study_data = study;
1334
1335 study->size = sizeof(pcre_study_data);
1336 study->flags = 0;
1337
1338 if (bits_set)
1339 {
1340 study->flags |= PCRE_STUDY_MAPPED;
1341 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1342 }
1343
1344 /* Always set the minlength value in the block, because the JIT compiler
1345 makes use of it. However, don't set the bit unless the length is greater than
1346 zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1347 checking the zero case. */
1348
1349 if (min > 0)
1350 {
1351 study->flags |= PCRE_STUDY_MINLEN;
1352 study->minlength = min;
1353 }
1354 else study->minlength = 0;
1355
1356 /* If JIT support was compiled and requested, attempt the JIT compilation.
1357 If no starting bytes were found, and the minimum length is zero, and JIT
1358 compilation fails, abandon the extra block and return NULL. */
1359
1360 #ifdef SUPPORT_JIT
1361 extra->executable_jit = NULL;
1362 if ((options & PCRE_STUDY_JIT_COMPILE) != 0) PRIV(jit_compile)(re, extra);
1363 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0)
1364 {
1365 pcre_free_study(extra);
1366 extra = NULL;
1367 }
1368 #endif
1369 }
1370
1371 return extra;
1372 }
1373
1374
1375 /*************************************************
1376 * Free the study data *
1377 *************************************************/
1378
1379 /* This function frees the memory that was obtained by pcre_study().
1380
1381 Argument: a pointer to the pcre_extra block
1382 Returns: nothing
1383 */
1384
1385 #ifdef COMPILE_PCRE8
1386 PCRE_EXP_DEFN void
1387 pcre_free_study(pcre_extra *extra)
1388 #else
1389 PCRE_EXP_DEFN void
1390 pcre16_free_study(pcre_extra *extra)
1391 #endif
1392 {
1393 #ifdef SUPPORT_JIT
1394 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1395 extra->executable_jit != NULL)
1396 PRIV(jit_free)(extra->executable_jit);
1397 #endif
1398 pcre_free(extra);
1399 }
1400
1401 /* End of pcre_study.c */

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