/[pcre]/code/trunk/pcre_study.c
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Revision 754 - (show annotations) (download)
Sat Nov 19 18:32:18 2011 UTC (2 years, 9 months ago) by ph10
File MIME type: text/plain
File size: 38961 byte(s)
Support \C in lookbehinds and DFA matching when not in UTF-8 mode.

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 uschar *code, const uschar *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 uschar *cc = (uschar *)code + 1 + LINK_SIZE;
89
90 if (*code == OP_CBRA || *code == OP_SCBRA ||
91 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += 2;
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 uschar *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 += _pcre_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 += _pcre_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 += _pcre_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 += 4;
247 #ifdef SUPPORT_UTF8
248 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
249 #endif
250 break;
251
252 case OP_TYPEEXACT:
253 branchlength += GET2(cc,1);
254 cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
255 break;
256
257 /* Handle single-char non-literal matchers */
258
259 case OP_PROP:
260 case OP_NOTPROP:
261 cc += 2;
262 /* Fall through */
263
264 case OP_NOT_DIGIT:
265 case OP_DIGIT:
266 case OP_NOT_WHITESPACE:
267 case OP_WHITESPACE:
268 case OP_NOT_WORDCHAR:
269 case OP_WORDCHAR:
270 case OP_ANY:
271 case OP_ALLANY:
272 case OP_EXTUNI:
273 case OP_HSPACE:
274 case OP_NOT_HSPACE:
275 case OP_VSPACE:
276 case OP_NOT_VSPACE:
277 branchlength++;
278 cc++;
279 break;
280
281 /* "Any newline" might match two characters, but it also might match just
282 one. */
283
284 case OP_ANYNL:
285 branchlength += 1;
286 cc++;
287 break;
288
289 /* The single-byte matcher means we can't proceed in UTF-8 mode. (In
290 non-UTF-8 mode \C will actually be turned into OP_ALLANY, so won't ever
291 appear, but leave the code, just in case.) */
292
293 case OP_ANYBYTE:
294 #ifdef SUPPORT_UTF8
295 if (utf8) return -1;
296 #endif
297 branchlength++;
298 cc++;
299 break;
300
301 /* For repeated character types, we have to test for \p and \P, which have
302 an extra two bytes of parameters. */
303
304 case OP_TYPESTAR:
305 case OP_TYPEMINSTAR:
306 case OP_TYPEQUERY:
307 case OP_TYPEMINQUERY:
308 case OP_TYPEPOSSTAR:
309 case OP_TYPEPOSQUERY:
310 if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
311 cc += _pcre_OP_lengths[op];
312 break;
313
314 case OP_TYPEUPTO:
315 case OP_TYPEMINUPTO:
316 case OP_TYPEPOSUPTO:
317 if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
318 cc += _pcre_OP_lengths[op];
319 break;
320
321 /* Check a class for variable quantification */
322
323 #ifdef SUPPORT_UTF8
324 case OP_XCLASS:
325 cc += GET(cc, 1) - 33;
326 /* Fall through */
327 #endif
328
329 case OP_CLASS:
330 case OP_NCLASS:
331 cc += 33;
332
333 switch (*cc)
334 {
335 case OP_CRPLUS:
336 case OP_CRMINPLUS:
337 branchlength++;
338 /* Fall through */
339
340 case OP_CRSTAR:
341 case OP_CRMINSTAR:
342 case OP_CRQUERY:
343 case OP_CRMINQUERY:
344 cc++;
345 break;
346
347 case OP_CRRANGE:
348 case OP_CRMINRANGE:
349 branchlength += GET2(cc,1);
350 cc += 5;
351 break;
352
353 default:
354 branchlength++;
355 break;
356 }
357 break;
358
359 /* Backreferences and subroutine calls are treated in the same way: we find
360 the minimum length for the subpattern. A recursion, however, causes an
361 a flag to be set that causes the length of this branch to be ignored. The
362 logic is that a recursion can only make sense if there is another
363 alternation that stops the recursing. That will provide the minimum length
364 (when no recursion happens). A backreference within the group that it is
365 referencing behaves in the same way.
366
367 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
368 matches an empty string (by default it causes a matching failure), so in
369 that case we must set the minimum length to zero. */
370
371 case OP_REF:
372 case OP_REFI:
373 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
374 {
375 ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
376 if (cs == NULL) return -2;
377 do ce += GET(ce, 1); while (*ce == OP_ALT);
378 if (cc > cs && cc < ce)
379 {
380 d = 0;
381 had_recurse = TRUE;
382 }
383 else
384 {
385 d = find_minlength(cs, startcode, options, recurse_depth);
386 }
387 }
388 else d = 0;
389 cc += 3;
390
391 /* Handle repeated back references */
392
393 switch (*cc)
394 {
395 case OP_CRSTAR:
396 case OP_CRMINSTAR:
397 case OP_CRQUERY:
398 case OP_CRMINQUERY:
399 min = 0;
400 cc++;
401 break;
402
403 case OP_CRPLUS:
404 case OP_CRMINPLUS:
405 min = 1;
406 cc++;
407 break;
408
409 case OP_CRRANGE:
410 case OP_CRMINRANGE:
411 min = GET2(cc, 1);
412 cc += 5;
413 break;
414
415 default:
416 min = 1;
417 break;
418 }
419
420 branchlength += min * d;
421 break;
422
423 /* We can easily detect direct recursion, but not mutual recursion. This is
424 caught by a recursion depth count. */
425
426 case OP_RECURSE:
427 cs = ce = (uschar *)startcode + GET(cc, 1);
428 do ce += GET(ce, 1); while (*ce == OP_ALT);
429 if ((cc > cs && cc < ce) || recurse_depth > 10)
430 had_recurse = TRUE;
431 else
432 {
433 branchlength += find_minlength(cs, startcode, options, recurse_depth + 1);
434 }
435 cc += 1 + LINK_SIZE;
436 break;
437
438 /* Anything else does not or need not match a character. We can get the
439 item's length from the table, but for those that can match zero occurrences
440 of a character, we must take special action for UTF-8 characters. As it
441 happens, the "NOT" versions of these opcodes are used at present only for
442 ASCII characters, so they could be omitted from this list. However, in
443 future that may change, so we include them here so as not to leave a
444 gotcha for a future maintainer. */
445
446 case OP_UPTO:
447 case OP_UPTOI:
448 case OP_NOTUPTO:
449 case OP_NOTUPTOI:
450 case OP_MINUPTO:
451 case OP_MINUPTOI:
452 case OP_NOTMINUPTO:
453 case OP_NOTMINUPTOI:
454 case OP_POSUPTO:
455 case OP_POSUPTOI:
456 case OP_NOTPOSUPTO:
457 case OP_NOTPOSUPTOI:
458
459 case OP_STAR:
460 case OP_STARI:
461 case OP_NOTSTAR:
462 case OP_NOTSTARI:
463 case OP_MINSTAR:
464 case OP_MINSTARI:
465 case OP_NOTMINSTAR:
466 case OP_NOTMINSTARI:
467 case OP_POSSTAR:
468 case OP_POSSTARI:
469 case OP_NOTPOSSTAR:
470 case OP_NOTPOSSTARI:
471
472 case OP_QUERY:
473 case OP_QUERYI:
474 case OP_NOTQUERY:
475 case OP_NOTQUERYI:
476 case OP_MINQUERY:
477 case OP_MINQUERYI:
478 case OP_NOTMINQUERY:
479 case OP_NOTMINQUERYI:
480 case OP_POSQUERY:
481 case OP_POSQUERYI:
482 case OP_NOTPOSQUERY:
483 case OP_NOTPOSQUERYI:
484
485 cc += _pcre_OP_lengths[op];
486 #ifdef SUPPORT_UTF8
487 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
488 #endif
489 break;
490
491 /* Skip these, but we need to add in the name length. */
492
493 case OP_MARK:
494 case OP_PRUNE_ARG:
495 case OP_SKIP_ARG:
496 case OP_THEN_ARG:
497 cc += _pcre_OP_lengths[op] + cc[1];
498 break;
499
500 /* The remaining opcodes are just skipped over. */
501
502 case OP_CLOSE:
503 case OP_COMMIT:
504 case OP_FAIL:
505 case OP_PRUNE:
506 case OP_SET_SOM:
507 case OP_SKIP:
508 case OP_THEN:
509 cc += _pcre_OP_lengths[op];
510 break;
511
512 /* This should not occur: we list all opcodes explicitly so that when
513 new ones get added they are properly considered. */
514
515 default:
516 return -3;
517 }
518 }
519 /* Control never gets here */
520 }
521
522
523
524 /*************************************************
525 * Set a bit and maybe its alternate case *
526 *************************************************/
527
528 /* Given a character, set its first byte's bit in the table, and also the
529 corresponding bit for the other version of a letter if we are caseless. In
530 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
531 when Unicode property support is available.
532
533 Arguments:
534 start_bits points to the bit map
535 p points to the character
536 caseless the caseless flag
537 cd the block with char table pointers
538 utf8 TRUE for UTF-8 mode
539
540 Returns: pointer after the character
541 */
542
543 static const uschar *
544 set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
545 compile_data *cd, BOOL utf8)
546 {
547 unsigned int c = *p;
548
549 SET_BIT(c);
550
551 #ifdef SUPPORT_UTF8
552 if (utf8 && c > 127)
553 {
554 GETCHARINC(c, p);
555 #ifdef SUPPORT_UCP
556 if (caseless)
557 {
558 uschar buff[8];
559 c = UCD_OTHERCASE(c);
560 (void)_pcre_ord2utf8(c, buff);
561 SET_BIT(buff[0]);
562 }
563 #endif
564 return p;
565 }
566 #endif
567
568 /* Not UTF-8 mode, or character is less than 127. */
569
570 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
571 return p + 1;
572 }
573
574
575
576 /*************************************************
577 * Set bits for a positive character type *
578 *************************************************/
579
580 /* This function sets starting bits for a character type. In UTF-8 mode, we can
581 only do a direct setting for bytes less than 128, as otherwise there can be
582 confusion with bytes in the middle of UTF-8 characters. In a "traditional"
583 environment, the tables will only recognize ASCII characters anyway, but in at
584 least one Windows environment, some higher bytes bits were set in the tables.
585 So we deal with that case by considering the UTF-8 encoding.
586
587 Arguments:
588 start_bits the starting bitmap
589 cbit type the type of character wanted
590 table_limit 32 for non-UTF-8; 16 for UTF-8
591 cd the block with char table pointers
592
593 Returns: nothing
594 */
595
596 static void
597 set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
598 compile_data *cd)
599 {
600 register int c;
601 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
602 if (table_limit == 32) return;
603 for (c = 128; c < 256; c++)
604 {
605 if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
606 {
607 uschar buff[8];
608 (void)_pcre_ord2utf8(c, buff);
609 SET_BIT(buff[0]);
610 }
611 }
612 }
613
614
615 /*************************************************
616 * Set bits for a negative character type *
617 *************************************************/
618
619 /* This function sets starting bits for a negative character type such as \D.
620 In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
621 otherwise there can be confusion with bytes in the middle of UTF-8 characters.
622 Unlike in the positive case, where we can set appropriate starting bits for
623 specific high-valued UTF-8 characters, in this case we have to set the bits for
624 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
625 0xc0 (192) for simplicity.
626
627 Arguments:
628 start_bits the starting bitmap
629 cbit type the type of character wanted
630 table_limit 32 for non-UTF-8; 16 for UTF-8
631 cd the block with char table pointers
632
633 Returns: nothing
634 */
635
636 static void
637 set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
638 compile_data *cd)
639 {
640 register int c;
641 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
642 if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
643 }
644
645
646
647 /*************************************************
648 * Create bitmap of starting bytes *
649 *************************************************/
650
651 /* This function scans a compiled unanchored expression recursively and
652 attempts to build a bitmap of the set of possible starting bytes. As time goes
653 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
654 useful for parenthesized groups in patterns such as (a*)b where the group
655 provides some optional starting bytes but scanning must continue at the outer
656 level to find at least one mandatory byte. At the outermost level, this
657 function fails unless the result is SSB_DONE.
658
659 Arguments:
660 code points to an expression
661 start_bits points to a 32-byte table, initialized to 0
662 utf8 TRUE if in UTF-8 mode
663 cd the block with char table pointers
664
665 Returns: SSB_FAIL => Failed to find any starting bytes
666 SSB_DONE => Found mandatory starting bytes
667 SSB_CONTINUE => Found optional starting bytes
668 SSB_UNKNOWN => Hit an unrecognized opcode
669 */
670
671 static int
672 set_start_bits(const uschar *code, uschar *start_bits, BOOL utf8,
673 compile_data *cd)
674 {
675 register int c;
676 int yield = SSB_DONE;
677 int table_limit = utf8? 16:32;
678
679 #if 0
680 /* ========================================================================= */
681 /* The following comment and code was inserted in January 1999. In May 2006,
682 when it was observed to cause compiler warnings about unused values, I took it
683 out again. If anybody is still using OS/2, they will have to put it back
684 manually. */
685
686 /* This next statement and the later reference to dummy are here in order to
687 trick the optimizer of the IBM C compiler for OS/2 into generating correct
688 code. Apparently IBM isn't going to fix the problem, and we would rather not
689 disable optimization (in this module it actually makes a big difference, and
690 the pcre module can use all the optimization it can get). */
691
692 volatile int dummy;
693 /* ========================================================================= */
694 #endif
695
696 do
697 {
698 BOOL try_next = TRUE;
699 const uschar *tcode = code + 1 + LINK_SIZE;
700
701 if (*code == OP_CBRA || *code == OP_SCBRA ||
702 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += 2;
703
704 while (try_next) /* Loop for items in this branch */
705 {
706 int rc;
707
708 switch(*tcode)
709 {
710 /* If we reach something we don't understand, it means a new opcode has
711 been created that hasn't been added to this code. Hopefully this problem
712 will be discovered during testing. */
713
714 default:
715 return SSB_UNKNOWN;
716
717 /* Fail for a valid opcode that implies no starting bits. */
718
719 case OP_ACCEPT:
720 case OP_ASSERT_ACCEPT:
721 case OP_ALLANY:
722 case OP_ANY:
723 case OP_ANYBYTE:
724 case OP_CIRC:
725 case OP_CIRCM:
726 case OP_CLOSE:
727 case OP_COMMIT:
728 case OP_COND:
729 case OP_CREF:
730 case OP_DEF:
731 case OP_DOLL:
732 case OP_DOLLM:
733 case OP_END:
734 case OP_EOD:
735 case OP_EODN:
736 case OP_EXTUNI:
737 case OP_FAIL:
738 case OP_MARK:
739 case OP_NCREF:
740 case OP_NOT:
741 case OP_NOTEXACT:
742 case OP_NOTEXACTI:
743 case OP_NOTI:
744 case OP_NOTMINPLUS:
745 case OP_NOTMINPLUSI:
746 case OP_NOTMINQUERY:
747 case OP_NOTMINQUERYI:
748 case OP_NOTMINSTAR:
749 case OP_NOTMINSTARI:
750 case OP_NOTMINUPTO:
751 case OP_NOTMINUPTOI:
752 case OP_NOTPLUS:
753 case OP_NOTPLUSI:
754 case OP_NOTPOSPLUS:
755 case OP_NOTPOSPLUSI:
756 case OP_NOTPOSQUERY:
757 case OP_NOTPOSQUERYI:
758 case OP_NOTPOSSTAR:
759 case OP_NOTPOSSTARI:
760 case OP_NOTPOSUPTO:
761 case OP_NOTPOSUPTOI:
762 case OP_NOTPROP:
763 case OP_NOTQUERY:
764 case OP_NOTQUERYI:
765 case OP_NOTSTAR:
766 case OP_NOTSTARI:
767 case OP_NOTUPTO:
768 case OP_NOTUPTOI:
769 case OP_NOT_HSPACE:
770 case OP_NOT_VSPACE:
771 case OP_NRREF:
772 case OP_PROP:
773 case OP_PRUNE:
774 case OP_PRUNE_ARG:
775 case OP_RECURSE:
776 case OP_REF:
777 case OP_REFI:
778 case OP_REVERSE:
779 case OP_RREF:
780 case OP_SCOND:
781 case OP_SET_SOM:
782 case OP_SKIP:
783 case OP_SKIP_ARG:
784 case OP_SOD:
785 case OP_SOM:
786 case OP_THEN:
787 case OP_THEN_ARG:
788 case OP_XCLASS:
789 return SSB_FAIL;
790
791 /* We can ignore word boundary tests. */
792
793 case OP_WORD_BOUNDARY:
794 case OP_NOT_WORD_BOUNDARY:
795 tcode++;
796 break;
797
798 /* If we hit a bracket or a positive lookahead assertion, recurse to set
799 bits from within the subpattern. If it can't find anything, we have to
800 give up. If it finds some mandatory character(s), we are done for this
801 branch. Otherwise, carry on scanning after the subpattern. */
802
803 case OP_BRA:
804 case OP_SBRA:
805 case OP_CBRA:
806 case OP_SCBRA:
807 case OP_BRAPOS:
808 case OP_SBRAPOS:
809 case OP_CBRAPOS:
810 case OP_SCBRAPOS:
811 case OP_ONCE:
812 case OP_ONCE_NC:
813 case OP_ASSERT:
814 rc = set_start_bits(tcode, start_bits, utf8, cd);
815 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
816 if (rc == SSB_DONE) try_next = FALSE; else
817 {
818 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
819 tcode += 1 + LINK_SIZE;
820 }
821 break;
822
823 /* If we hit ALT or KET, it means we haven't found anything mandatory in
824 this branch, though we might have found something optional. For ALT, we
825 continue with the next alternative, but we have to arrange that the final
826 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
827 return SSB_CONTINUE: if this is the top level, that indicates failure,
828 but after a nested subpattern, it causes scanning to continue. */
829
830 case OP_ALT:
831 yield = SSB_CONTINUE;
832 try_next = FALSE;
833 break;
834
835 case OP_KET:
836 case OP_KETRMAX:
837 case OP_KETRMIN:
838 case OP_KETRPOS:
839 return SSB_CONTINUE;
840
841 /* Skip over callout */
842
843 case OP_CALLOUT:
844 tcode += 2 + 2*LINK_SIZE;
845 break;
846
847 /* Skip over lookbehind and negative lookahead assertions */
848
849 case OP_ASSERT_NOT:
850 case OP_ASSERTBACK:
851 case OP_ASSERTBACK_NOT:
852 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
853 tcode += 1 + LINK_SIZE;
854 break;
855
856 /* BRAZERO does the bracket, but carries on. */
857
858 case OP_BRAZERO:
859 case OP_BRAMINZERO:
860 case OP_BRAPOSZERO:
861 rc = set_start_bits(++tcode, start_bits, utf8, cd);
862 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
863 /* =========================================================================
864 See the comment at the head of this function concerning the next line,
865 which was an old fudge for the benefit of OS/2.
866 dummy = 1;
867 ========================================================================= */
868 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
869 tcode += 1 + LINK_SIZE;
870 break;
871
872 /* SKIPZERO skips the bracket. */
873
874 case OP_SKIPZERO:
875 tcode++;
876 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
877 tcode += 1 + LINK_SIZE;
878 break;
879
880 /* Single-char * or ? sets the bit and tries the next item */
881
882 case OP_STAR:
883 case OP_MINSTAR:
884 case OP_POSSTAR:
885 case OP_QUERY:
886 case OP_MINQUERY:
887 case OP_POSQUERY:
888 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
889 break;
890
891 case OP_STARI:
892 case OP_MINSTARI:
893 case OP_POSSTARI:
894 case OP_QUERYI:
895 case OP_MINQUERYI:
896 case OP_POSQUERYI:
897 tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
898 break;
899
900 /* Single-char upto sets the bit and tries the next */
901
902 case OP_UPTO:
903 case OP_MINUPTO:
904 case OP_POSUPTO:
905 tcode = set_table_bit(start_bits, tcode + 3, FALSE, cd, utf8);
906 break;
907
908 case OP_UPTOI:
909 case OP_MINUPTOI:
910 case OP_POSUPTOI:
911 tcode = set_table_bit(start_bits, tcode + 3, TRUE, cd, utf8);
912 break;
913
914 /* At least one single char sets the bit and stops */
915
916 case OP_EXACT:
917 tcode += 2;
918 /* Fall through */
919 case OP_CHAR:
920 case OP_PLUS:
921 case OP_MINPLUS:
922 case OP_POSPLUS:
923 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
924 try_next = FALSE;
925 break;
926
927 case OP_EXACTI:
928 tcode += 2;
929 /* Fall through */
930 case OP_CHARI:
931 case OP_PLUSI:
932 case OP_MINPLUSI:
933 case OP_POSPLUSI:
934 (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
935 try_next = FALSE;
936 break;
937
938 /* Special spacing and line-terminating items. These recognize specific
939 lists of characters. The difference between VSPACE and ANYNL is that the
940 latter can match the two-character CRLF sequence, but that is not
941 relevant for finding the first character, so their code here is
942 identical. */
943
944 case OP_HSPACE:
945 SET_BIT(0x09);
946 SET_BIT(0x20);
947 if (utf8)
948 {
949 SET_BIT(0xC2); /* For U+00A0 */
950 SET_BIT(0xE1); /* For U+1680, U+180E */
951 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
952 SET_BIT(0xE3); /* For U+3000 */
953 }
954 else SET_BIT(0xA0);
955 try_next = FALSE;
956 break;
957
958 case OP_ANYNL:
959 case OP_VSPACE:
960 SET_BIT(0x0A);
961 SET_BIT(0x0B);
962 SET_BIT(0x0C);
963 SET_BIT(0x0D);
964 if (utf8)
965 {
966 SET_BIT(0xC2); /* For U+0085 */
967 SET_BIT(0xE2); /* For U+2028, U+2029 */
968 }
969 else SET_BIT(0x85);
970 try_next = FALSE;
971 break;
972
973 /* Single character types set the bits and stop. Note that if PCRE_UCP
974 is set, we do not see these op codes because \d etc are converted to
975 properties. Therefore, these apply in the case when only characters less
976 than 256 are recognized to match the types. */
977
978 case OP_NOT_DIGIT:
979 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
980 try_next = FALSE;
981 break;
982
983 case OP_DIGIT:
984 set_type_bits(start_bits, cbit_digit, table_limit, cd);
985 try_next = FALSE;
986 break;
987
988 /* The cbit_space table has vertical tab as whitespace; we have to
989 ensure it is set as not whitespace. */
990
991 case OP_NOT_WHITESPACE:
992 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
993 start_bits[1] |= 0x08;
994 try_next = FALSE;
995 break;
996
997 /* The cbit_space table has vertical tab as whitespace; we have to
998 not set it from the table. */
999
1000 case OP_WHITESPACE:
1001 c = start_bits[1]; /* Save in case it was already set */
1002 set_type_bits(start_bits, cbit_space, table_limit, cd);
1003 start_bits[1] = (start_bits[1] & ~0x08) | c;
1004 try_next = FALSE;
1005 break;
1006
1007 case OP_NOT_WORDCHAR:
1008 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1009 try_next = FALSE;
1010 break;
1011
1012 case OP_WORDCHAR:
1013 set_type_bits(start_bits, cbit_word, table_limit, cd);
1014 try_next = FALSE;
1015 break;
1016
1017 /* One or more character type fudges the pointer and restarts, knowing
1018 it will hit a single character type and stop there. */
1019
1020 case OP_TYPEPLUS:
1021 case OP_TYPEMINPLUS:
1022 case OP_TYPEPOSPLUS:
1023 tcode++;
1024 break;
1025
1026 case OP_TYPEEXACT:
1027 tcode += 3;
1028 break;
1029
1030 /* Zero or more repeats of character types set the bits and then
1031 try again. */
1032
1033 case OP_TYPEUPTO:
1034 case OP_TYPEMINUPTO:
1035 case OP_TYPEPOSUPTO:
1036 tcode += 2; /* Fall through */
1037
1038 case OP_TYPESTAR:
1039 case OP_TYPEMINSTAR:
1040 case OP_TYPEPOSSTAR:
1041 case OP_TYPEQUERY:
1042 case OP_TYPEMINQUERY:
1043 case OP_TYPEPOSQUERY:
1044 switch(tcode[1])
1045 {
1046 default:
1047 case OP_ANY:
1048 case OP_ALLANY:
1049 return SSB_FAIL;
1050
1051 case OP_HSPACE:
1052 SET_BIT(0x09);
1053 SET_BIT(0x20);
1054 if (utf8)
1055 {
1056 SET_BIT(0xC2); /* For U+00A0 */
1057 SET_BIT(0xE1); /* For U+1680, U+180E */
1058 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1059 SET_BIT(0xE3); /* For U+3000 */
1060 }
1061 else SET_BIT(0xA0);
1062 break;
1063
1064 case OP_ANYNL:
1065 case OP_VSPACE:
1066 SET_BIT(0x0A);
1067 SET_BIT(0x0B);
1068 SET_BIT(0x0C);
1069 SET_BIT(0x0D);
1070 if (utf8)
1071 {
1072 SET_BIT(0xC2); /* For U+0085 */
1073 SET_BIT(0xE2); /* For U+2028, U+2029 */
1074 }
1075 else SET_BIT(0x85);
1076 break;
1077
1078 case OP_NOT_DIGIT:
1079 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1080 break;
1081
1082 case OP_DIGIT:
1083 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1084 break;
1085
1086 /* The cbit_space table has vertical tab as whitespace; we have to
1087 ensure it gets set as not whitespace. */
1088
1089 case OP_NOT_WHITESPACE:
1090 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1091 start_bits[1] |= 0x08;
1092 break;
1093
1094 /* The cbit_space table has vertical tab as whitespace; we have to
1095 avoid setting it. */
1096
1097 case OP_WHITESPACE:
1098 c = start_bits[1]; /* Save in case it was already set */
1099 set_type_bits(start_bits, cbit_space, table_limit, cd);
1100 start_bits[1] = (start_bits[1] & ~0x08) | c;
1101 break;
1102
1103 case OP_NOT_WORDCHAR:
1104 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1105 break;
1106
1107 case OP_WORDCHAR:
1108 set_type_bits(start_bits, cbit_word, table_limit, cd);
1109 break;
1110 }
1111
1112 tcode += 2;
1113 break;
1114
1115 /* Character class where all the information is in a bit map: set the
1116 bits and either carry on or not, according to the repeat count. If it was
1117 a negative class, and we are operating with UTF-8 characters, any byte
1118 with a value >= 0xc4 is a potentially valid starter because it starts a
1119 character with a value > 255. */
1120
1121 case OP_NCLASS:
1122 #ifdef SUPPORT_UTF8
1123 if (utf8)
1124 {
1125 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1126 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1127 }
1128 #endif
1129 /* Fall through */
1130
1131 case OP_CLASS:
1132 {
1133 tcode++;
1134
1135 /* In UTF-8 mode, the bits in a bit map correspond to character
1136 values, not to byte values. However, the bit map we are constructing is
1137 for byte values. So we have to do a conversion for characters whose
1138 value is > 127. In fact, there are only two possible starting bytes for
1139 characters in the range 128 - 255. */
1140
1141 #ifdef SUPPORT_UTF8
1142 if (utf8)
1143 {
1144 for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
1145 for (c = 128; c < 256; c++)
1146 {
1147 if ((tcode[c/8] && (1 << (c&7))) != 0)
1148 {
1149 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1150 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1151 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1152 }
1153 }
1154 }
1155
1156 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1157
1158 else
1159 #endif
1160 {
1161 for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
1162 }
1163
1164 /* Advance past the bit map, and act on what follows. For a zero
1165 minimum repeat, continue; otherwise stop processing. */
1166
1167 tcode += 32;
1168 switch (*tcode)
1169 {
1170 case OP_CRSTAR:
1171 case OP_CRMINSTAR:
1172 case OP_CRQUERY:
1173 case OP_CRMINQUERY:
1174 tcode++;
1175 break;
1176
1177 case OP_CRRANGE:
1178 case OP_CRMINRANGE:
1179 if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
1180 else try_next = FALSE;
1181 break;
1182
1183 default:
1184 try_next = FALSE;
1185 break;
1186 }
1187 }
1188 break; /* End of bitmap class handling */
1189
1190 } /* End of switch */
1191 } /* End of try_next loop */
1192
1193 code += GET(code, 1); /* Advance to next branch */
1194 }
1195 while (*code == OP_ALT);
1196 return yield;
1197 }
1198
1199
1200
1201
1202
1203 /*************************************************
1204 * Study a compiled expression *
1205 *************************************************/
1206
1207 /* This function is handed a compiled expression that it must study to produce
1208 information that will speed up the matching. It returns a pcre_extra block
1209 which then gets handed back to pcre_exec().
1210
1211 Arguments:
1212 re points to the compiled expression
1213 options contains option bits
1214 errorptr points to where to place error messages;
1215 set NULL unless error
1216
1217 Returns: pointer to a pcre_extra block, with study_data filled in and the
1218 appropriate flags set;
1219 NULL on error or if no optimization possible
1220 */
1221
1222 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1223 pcre_study(const pcre *external_re, int options, const char **errorptr)
1224 {
1225 int min;
1226 BOOL bits_set = FALSE;
1227 uschar start_bits[32];
1228 pcre_extra *extra = NULL;
1229 pcre_study_data *study;
1230 const uschar *tables;
1231 uschar *code;
1232 compile_data compile_block;
1233 const real_pcre *re = (const real_pcre *)external_re;
1234
1235 *errorptr = NULL;
1236
1237 if (re == NULL || re->magic_number != MAGIC_NUMBER)
1238 {
1239 *errorptr = "argument is not a compiled regular expression";
1240 return NULL;
1241 }
1242
1243 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1244 {
1245 *errorptr = "unknown or incorrect option bit(s) set";
1246 return NULL;
1247 }
1248
1249 code = (uschar *)re + re->name_table_offset +
1250 (re->name_count * re->name_entry_size);
1251
1252 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1253 a multiline pattern that matches only at "line starts", there is no point in
1254 seeking a list of starting bytes. */
1255
1256 if ((re->options & PCRE_ANCHORED) == 0 &&
1257 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1258 {
1259 int rc;
1260
1261 /* Set the character tables in the block that is passed around */
1262
1263 tables = re->tables;
1264 if (tables == NULL)
1265 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1266 (void *)(&tables));
1267
1268 compile_block.lcc = tables + lcc_offset;
1269 compile_block.fcc = tables + fcc_offset;
1270 compile_block.cbits = tables + cbits_offset;
1271 compile_block.ctypes = tables + ctypes_offset;
1272
1273 /* See if we can find a fixed set of initial characters for the pattern. */
1274
1275 memset(start_bits, 0, 32 * sizeof(uschar));
1276 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1277 &compile_block);
1278 bits_set = rc == SSB_DONE;
1279 if (rc == SSB_UNKNOWN)
1280 {
1281 *errorptr = "internal error: opcode not recognized";
1282 return NULL;
1283 }
1284 }
1285
1286 /* Find the minimum length of subject string. */
1287
1288 switch(min = find_minlength(code, code, re->options, 0))
1289 {
1290 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1291 case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1292 default: break;
1293 }
1294
1295 /* If a set of starting bytes has been identified, or if the minimum length is
1296 greater than zero, or if JIT optimization has been requested, get a pcre_extra
1297 block and a pcre_study_data block. The study data is put in the latter, which
1298 is pointed to by the former, which may also get additional data set later by
1299 the calling program. At the moment, the size of pcre_study_data is fixed. We
1300 nevertheless save it in a field for returning via the pcre_fullinfo() function
1301 so that if it becomes variable in the future, we don't have to change that
1302 code. */
1303
1304 if (bits_set || min > 0
1305 #ifdef SUPPORT_JIT
1306 || (options & PCRE_STUDY_JIT_COMPILE) != 0
1307 #endif
1308 )
1309 {
1310 extra = (pcre_extra *)(pcre_malloc)
1311 (sizeof(pcre_extra) + sizeof(pcre_study_data));
1312 if (extra == NULL)
1313 {
1314 *errorptr = "failed to get memory";
1315 return NULL;
1316 }
1317
1318 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1319 extra->flags = PCRE_EXTRA_STUDY_DATA;
1320 extra->study_data = study;
1321
1322 study->size = sizeof(pcre_study_data);
1323 study->flags = 0;
1324
1325 if (bits_set)
1326 {
1327 study->flags |= PCRE_STUDY_MAPPED;
1328 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1329 }
1330
1331 /* Always set the minlength value in the block, because the JIT compiler
1332 makes use of it. However, don't set the bit unless the length is greater than
1333 zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1334 checking the zero case. */
1335
1336 if (min > 0)
1337 {
1338 study->flags |= PCRE_STUDY_MINLEN;
1339 study->minlength = min;
1340 }
1341 else study->minlength = 0;
1342
1343 /* If JIT support was compiled and requested, attempt the JIT compilation.
1344 If no starting bytes were found, and the minimum length is zero, and JIT
1345 compilation fails, abandon the extra block and return NULL. */
1346
1347 #ifdef SUPPORT_JIT
1348 extra->executable_jit = NULL;
1349 if ((options & PCRE_STUDY_JIT_COMPILE) != 0) _pcre_jit_compile(re, extra);
1350 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0)
1351 {
1352 pcre_free_study(extra);
1353 extra = NULL;
1354 }
1355 #endif
1356 }
1357
1358 return extra;
1359 }
1360
1361
1362 /*************************************************
1363 * Free the study data *
1364 *************************************************/
1365
1366 /* This function frees the memory that was obtained by pcre_study().
1367
1368 Argument: a pointer to the pcre_extra block
1369 Returns: nothing
1370 */
1371
1372 PCRE_EXP_DEFN void
1373 pcre_free_study(pcre_extra *extra)
1374 {
1375 #ifdef SUPPORT_JIT
1376 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1377 extra->executable_jit != NULL)
1378 _pcre_jit_free(extra->executable_jit);
1379 #endif
1380 pcre_free(extra);
1381 }
1382
1383 /* End of pcre_study.c */

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