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Revision 550 - (show annotations) (download)
Sun Oct 10 16:24:11 2010 UTC (4 years, 1 month ago) by ph10
File MIME type: text/plain
File size: 32236 byte(s)
Fix problem with (*THEN) not backing up far enough.

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 };
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
73 Returns: the minimum length
74 -1 if \C was encountered
75 -2 internal error (missing capturing bracket)
76 */
77
78 static int
79 find_minlength(const uschar *code, const uschar *startcode, int options)
80 {
81 int length = -1;
82 BOOL utf8 = (options & PCRE_UTF8) != 0;
83 BOOL had_recurse = FALSE;
84 register int branchlength = 0;
85 register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
86
87 if (*code == OP_CBRA || *code == OP_SCBRA) cc += 2;
88
89 /* Scan along the opcodes for this branch. If we get to the end of the
90 branch, check the length against that of the other branches. */
91
92 for (;;)
93 {
94 int d, min;
95 uschar *cs, *ce;
96 register int op = *cc;
97
98 switch (op)
99 {
100 case OP_COND:
101 case OP_SCOND:
102
103 /* If there is only one branch in a condition, the implied branch has zero
104 length, so we don't add anything. This covers the DEFINE "condition"
105 automatically. */
106
107 cs = cc + GET(cc, 1);
108 if (*cs != OP_ALT)
109 {
110 cc = cs + 1 + LINK_SIZE;
111 break;
112 }
113
114 /* Otherwise we can fall through and treat it the same as any other
115 subpattern. */
116
117 case OP_CBRA:
118 case OP_SCBRA:
119 case OP_BRA:
120 case OP_SBRA:
121 case OP_ONCE:
122 d = find_minlength(cc, startcode, options);
123 if (d < 0) return d;
124 branchlength += d;
125 do cc += GET(cc, 1); while (*cc == OP_ALT);
126 cc += 1 + LINK_SIZE;
127 break;
128
129 /* Reached end of a branch; if it's a ket it is the end of a nested
130 call. If it's ALT it is an alternation in a nested call. If it is
131 END it's the end of the outer call. All can be handled by the same code. */
132
133 case OP_ALT:
134 case OP_KET:
135 case OP_KETRMAX:
136 case OP_KETRMIN:
137 case OP_END:
138 if (length < 0 || (!had_recurse && branchlength < length))
139 length = branchlength;
140 if (*cc != OP_ALT) return length;
141 cc += 1 + LINK_SIZE;
142 branchlength = 0;
143 had_recurse = FALSE;
144 break;
145
146 /* Skip over assertive subpatterns */
147
148 case OP_ASSERT:
149 case OP_ASSERT_NOT:
150 case OP_ASSERTBACK:
151 case OP_ASSERTBACK_NOT:
152 do cc += GET(cc, 1); while (*cc == OP_ALT);
153 /* Fall through */
154
155 /* Skip over things that don't match chars */
156
157 case OP_REVERSE:
158 case OP_CREF:
159 case OP_NCREF:
160 case OP_RREF:
161 case OP_NRREF:
162 case OP_DEF:
163 case OP_OPT:
164 case OP_CALLOUT:
165 case OP_SOD:
166 case OP_SOM:
167 case OP_EOD:
168 case OP_EODN:
169 case OP_CIRC:
170 case OP_DOLL:
171 case OP_NOT_WORD_BOUNDARY:
172 case OP_WORD_BOUNDARY:
173 cc += _pcre_OP_lengths[*cc];
174 break;
175
176 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
177
178 case OP_BRAZERO:
179 case OP_BRAMINZERO:
180 case OP_SKIPZERO:
181 cc += _pcre_OP_lengths[*cc];
182 do cc += GET(cc, 1); while (*cc == OP_ALT);
183 cc += 1 + LINK_SIZE;
184 break;
185
186 /* Handle literal characters and + repetitions */
187
188 case OP_CHAR:
189 case OP_CHARNC:
190 case OP_NOT:
191 case OP_PLUS:
192 case OP_MINPLUS:
193 case OP_POSPLUS:
194 case OP_NOTPLUS:
195 case OP_NOTMINPLUS:
196 case OP_NOTPOSPLUS:
197 branchlength++;
198 cc += 2;
199 #ifdef SUPPORT_UTF8
200 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
201 #endif
202 break;
203
204 case OP_TYPEPLUS:
205 case OP_TYPEMINPLUS:
206 case OP_TYPEPOSPLUS:
207 branchlength++;
208 cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
209 break;
210
211 /* Handle exact repetitions. The count is already in characters, but we
212 need to skip over a multibyte character in UTF8 mode. */
213
214 case OP_EXACT:
215 case OP_NOTEXACT:
216 branchlength += GET2(cc,1);
217 cc += 4;
218 #ifdef SUPPORT_UTF8
219 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
220 #endif
221 break;
222
223 case OP_TYPEEXACT:
224 branchlength += GET2(cc,1);
225 cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
226 break;
227
228 /* Handle single-char non-literal matchers */
229
230 case OP_PROP:
231 case OP_NOTPROP:
232 cc += 2;
233 /* Fall through */
234
235 case OP_NOT_DIGIT:
236 case OP_DIGIT:
237 case OP_NOT_WHITESPACE:
238 case OP_WHITESPACE:
239 case OP_NOT_WORDCHAR:
240 case OP_WORDCHAR:
241 case OP_ANY:
242 case OP_ALLANY:
243 case OP_EXTUNI:
244 case OP_HSPACE:
245 case OP_NOT_HSPACE:
246 case OP_VSPACE:
247 case OP_NOT_VSPACE:
248 branchlength++;
249 cc++;
250 break;
251
252 /* "Any newline" might match two characters */
253
254 case OP_ANYNL:
255 branchlength += 2;
256 cc++;
257 break;
258
259 /* The single-byte matcher means we can't proceed in UTF-8 mode */
260
261 case OP_ANYBYTE:
262 #ifdef SUPPORT_UTF8
263 if (utf8) return -1;
264 #endif
265 branchlength++;
266 cc++;
267 break;
268
269 /* For repeated character types, we have to test for \p and \P, which have
270 an extra two bytes of parameters. */
271
272 case OP_TYPESTAR:
273 case OP_TYPEMINSTAR:
274 case OP_TYPEQUERY:
275 case OP_TYPEMINQUERY:
276 case OP_TYPEPOSSTAR:
277 case OP_TYPEPOSQUERY:
278 if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
279 cc += _pcre_OP_lengths[op];
280 break;
281
282 case OP_TYPEUPTO:
283 case OP_TYPEMINUPTO:
284 case OP_TYPEPOSUPTO:
285 if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
286 cc += _pcre_OP_lengths[op];
287 break;
288
289 /* Check a class for variable quantification */
290
291 #ifdef SUPPORT_UTF8
292 case OP_XCLASS:
293 cc += GET(cc, 1) - 33;
294 /* Fall through */
295 #endif
296
297 case OP_CLASS:
298 case OP_NCLASS:
299 cc += 33;
300
301 switch (*cc)
302 {
303 case OP_CRPLUS:
304 case OP_CRMINPLUS:
305 branchlength++;
306 /* Fall through */
307
308 case OP_CRSTAR:
309 case OP_CRMINSTAR:
310 case OP_CRQUERY:
311 case OP_CRMINQUERY:
312 cc++;
313 break;
314
315 case OP_CRRANGE:
316 case OP_CRMINRANGE:
317 branchlength += GET2(cc,1);
318 cc += 5;
319 break;
320
321 default:
322 branchlength++;
323 break;
324 }
325 break;
326
327 /* Backreferences and subroutine calls are treated in the same way: we find
328 the minimum length for the subpattern. A recursion, however, causes an
329 a flag to be set that causes the length of this branch to be ignored. The
330 logic is that a recursion can only make sense if there is another
331 alternation that stops the recursing. That will provide the minimum length
332 (when no recursion happens). A backreference within the group that it is
333 referencing behaves in the same way.
334
335 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
336 matches an empty string (by default it causes a matching failure), so in
337 that case we must set the minimum length to zero. */
338
339 case OP_REF:
340 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
341 {
342 ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
343 if (cs == NULL) return -2;
344 do ce += GET(ce, 1); while (*ce == OP_ALT);
345 if (cc > cs && cc < ce)
346 {
347 d = 0;
348 had_recurse = TRUE;
349 }
350 else d = find_minlength(cs, startcode, options);
351 }
352 else d = 0;
353 cc += 3;
354
355 /* Handle repeated back references */
356
357 switch (*cc)
358 {
359 case OP_CRSTAR:
360 case OP_CRMINSTAR:
361 case OP_CRQUERY:
362 case OP_CRMINQUERY:
363 min = 0;
364 cc++;
365 break;
366
367 case OP_CRRANGE:
368 case OP_CRMINRANGE:
369 min = GET2(cc, 1);
370 cc += 5;
371 break;
372
373 default:
374 min = 1;
375 break;
376 }
377
378 branchlength += min * d;
379 break;
380
381 case OP_RECURSE:
382 cs = ce = (uschar *)startcode + GET(cc, 1);
383 if (cs == NULL) return -2;
384 do ce += GET(ce, 1); while (*ce == OP_ALT);
385 if (cc > cs && cc < ce)
386 had_recurse = TRUE;
387 else
388 branchlength += find_minlength(cs, startcode, options);
389 cc += 1 + LINK_SIZE;
390 break;
391
392 /* Anything else does not or need not match a character. We can get the
393 item's length from the table, but for those that can match zero occurrences
394 of a character, we must take special action for UTF-8 characters. */
395
396 case OP_UPTO:
397 case OP_NOTUPTO:
398 case OP_MINUPTO:
399 case OP_NOTMINUPTO:
400 case OP_POSUPTO:
401 case OP_STAR:
402 case OP_MINSTAR:
403 case OP_NOTMINSTAR:
404 case OP_POSSTAR:
405 case OP_NOTPOSSTAR:
406 case OP_QUERY:
407 case OP_MINQUERY:
408 case OP_NOTMINQUERY:
409 case OP_POSQUERY:
410 case OP_NOTPOSQUERY:
411 cc += _pcre_OP_lengths[op];
412 #ifdef SUPPORT_UTF8
413 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
414 #endif
415 break;
416
417 /* Skip these, but we need to add in the name length. */
418
419 case OP_MARK:
420 case OP_PRUNE_ARG:
421 case OP_SKIP_ARG:
422 cc += _pcre_OP_lengths[op] + cc[1];
423 break;
424
425 case OP_THEN_ARG:
426 cc += _pcre_OP_lengths[op] + cc[1+LINK_SIZE];
427 break;
428
429 /* For the record, these are the opcodes that are matched by "default":
430 OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
431 OP_THEN. */
432
433 default:
434 cc += _pcre_OP_lengths[op];
435 break;
436 }
437 }
438 /* Control never gets here */
439 }
440
441
442
443 /*************************************************
444 * Set a bit and maybe its alternate case *
445 *************************************************/
446
447 /* Given a character, set its first byte's bit in the table, and also the
448 corresponding bit for the other version of a letter if we are caseless. In
449 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
450 when Unicode property support is available.
451
452 Arguments:
453 start_bits points to the bit map
454 p points to the character
455 caseless the caseless flag
456 cd the block with char table pointers
457 utf8 TRUE for UTF-8 mode
458
459 Returns: pointer after the character
460 */
461
462 static const uschar *
463 set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
464 compile_data *cd, BOOL utf8)
465 {
466 unsigned int c = *p;
467
468 SET_BIT(c);
469
470 #ifdef SUPPORT_UTF8
471 if (utf8 && c > 127)
472 {
473 GETCHARINC(c, p);
474 #ifdef SUPPORT_UCP
475 if (caseless)
476 {
477 uschar buff[8];
478 c = UCD_OTHERCASE(c);
479 (void)_pcre_ord2utf8(c, buff);
480 SET_BIT(buff[0]);
481 }
482 #endif
483 return p;
484 }
485 #endif
486
487 /* Not UTF-8 mode, or character is less than 127. */
488
489 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
490 return p + 1;
491 }
492
493
494
495 /*************************************************
496 * Set bits for a positive character type *
497 *************************************************/
498
499 /* This function sets starting bits for a character type. In UTF-8 mode, we can
500 only do a direct setting for bytes less than 128, as otherwise there can be
501 confusion with bytes in the middle of UTF-8 characters. In a "traditional"
502 environment, the tables will only recognize ASCII characters anyway, but in at
503 least one Windows environment, some higher bytes bits were set in the tables.
504 So we deal with that case by considering the UTF-8 encoding.
505
506 Arguments:
507 start_bits the starting bitmap
508 cbit type the type of character wanted
509 table_limit 32 for non-UTF-8; 16 for UTF-8
510 cd the block with char table pointers
511
512 Returns: nothing
513 */
514
515 static void
516 set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
517 compile_data *cd)
518 {
519 register int c;
520 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
521 if (table_limit == 32) return;
522 for (c = 128; c < 256; c++)
523 {
524 if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
525 {
526 uschar buff[8];
527 (void)_pcre_ord2utf8(c, buff);
528 SET_BIT(buff[0]);
529 }
530 }
531 }
532
533
534 /*************************************************
535 * Set bits for a negative character type *
536 *************************************************/
537
538 /* This function sets starting bits for a negative character type such as \D.
539 In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
540 otherwise there can be confusion with bytes in the middle of UTF-8 characters.
541 Unlike in the positive case, where we can set appropriate starting bits for
542 specific high-valued UTF-8 characters, in this case we have to set the bits for
543 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
544 0xc0 (192) for simplicity.
545
546 Arguments:
547 start_bits the starting bitmap
548 cbit type the type of character wanted
549 table_limit 32 for non-UTF-8; 16 for UTF-8
550 cd the block with char table pointers
551
552 Returns: nothing
553 */
554
555 static void
556 set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
557 compile_data *cd)
558 {
559 register int c;
560 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
561 if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
562 }
563
564
565
566 /*************************************************
567 * Create bitmap of starting bytes *
568 *************************************************/
569
570 /* This function scans a compiled unanchored expression recursively and
571 attempts to build a bitmap of the set of possible starting bytes. As time goes
572 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
573 useful for parenthesized groups in patterns such as (a*)b where the group
574 provides some optional starting bytes but scanning must continue at the outer
575 level to find at least one mandatory byte. At the outermost level, this
576 function fails unless the result is SSB_DONE.
577
578 Arguments:
579 code points to an expression
580 start_bits points to a 32-byte table, initialized to 0
581 caseless the current state of the caseless flag
582 utf8 TRUE if in UTF-8 mode
583 cd the block with char table pointers
584
585 Returns: SSB_FAIL => Failed to find any starting bytes
586 SSB_DONE => Found mandatory starting bytes
587 SSB_CONTINUE => Found optional starting bytes
588 */
589
590 static int
591 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
592 BOOL utf8, compile_data *cd)
593 {
594 register int c;
595 int yield = SSB_DONE;
596 int table_limit = utf8? 16:32;
597
598 #if 0
599 /* ========================================================================= */
600 /* The following comment and code was inserted in January 1999. In May 2006,
601 when it was observed to cause compiler warnings about unused values, I took it
602 out again. If anybody is still using OS/2, they will have to put it back
603 manually. */
604
605 /* This next statement and the later reference to dummy are here in order to
606 trick the optimizer of the IBM C compiler for OS/2 into generating correct
607 code. Apparently IBM isn't going to fix the problem, and we would rather not
608 disable optimization (in this module it actually makes a big difference, and
609 the pcre module can use all the optimization it can get). */
610
611 volatile int dummy;
612 /* ========================================================================= */
613 #endif
614
615 do
616 {
617 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
618 BOOL try_next = TRUE;
619
620 while (try_next) /* Loop for items in this branch */
621 {
622 int rc;
623 switch(*tcode)
624 {
625 /* Fail if we reach something we don't understand */
626
627 default:
628 return SSB_FAIL;
629
630 /* If we hit a bracket or a positive lookahead assertion, recurse to set
631 bits from within the subpattern. If it can't find anything, we have to
632 give up. If it finds some mandatory character(s), we are done for this
633 branch. Otherwise, carry on scanning after the subpattern. */
634
635 case OP_BRA:
636 case OP_SBRA:
637 case OP_CBRA:
638 case OP_SCBRA:
639 case OP_ONCE:
640 case OP_ASSERT:
641 rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
642 if (rc == SSB_FAIL) return SSB_FAIL;
643 if (rc == SSB_DONE) try_next = FALSE; else
644 {
645 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
646 tcode += 1 + LINK_SIZE;
647 }
648 break;
649
650 /* If we hit ALT or KET, it means we haven't found anything mandatory in
651 this branch, though we might have found something optional. For ALT, we
652 continue with the next alternative, but we have to arrange that the final
653 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
654 return SSB_CONTINUE: if this is the top level, that indicates failure,
655 but after a nested subpattern, it causes scanning to continue. */
656
657 case OP_ALT:
658 yield = SSB_CONTINUE;
659 try_next = FALSE;
660 break;
661
662 case OP_KET:
663 case OP_KETRMAX:
664 case OP_KETRMIN:
665 return SSB_CONTINUE;
666
667 /* Skip over callout */
668
669 case OP_CALLOUT:
670 tcode += 2 + 2*LINK_SIZE;
671 break;
672
673 /* Skip over lookbehind and negative lookahead assertions */
674
675 case OP_ASSERT_NOT:
676 case OP_ASSERTBACK:
677 case OP_ASSERTBACK_NOT:
678 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
679 tcode += 1 + LINK_SIZE;
680 break;
681
682 /* Skip over an option setting, changing the caseless flag */
683
684 case OP_OPT:
685 caseless = (tcode[1] & PCRE_CASELESS) != 0;
686 tcode += 2;
687 break;
688
689 /* BRAZERO does the bracket, but carries on. */
690
691 case OP_BRAZERO:
692 case OP_BRAMINZERO:
693 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
694 return SSB_FAIL;
695 /* =========================================================================
696 See the comment at the head of this function concerning the next line,
697 which was an old fudge for the benefit of OS/2.
698 dummy = 1;
699 ========================================================================= */
700 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
701 tcode += 1 + LINK_SIZE;
702 break;
703
704 /* SKIPZERO skips the bracket. */
705
706 case OP_SKIPZERO:
707 tcode++;
708 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
709 tcode += 1 + LINK_SIZE;
710 break;
711
712 /* Single-char * or ? sets the bit and tries the next item */
713
714 case OP_STAR:
715 case OP_MINSTAR:
716 case OP_POSSTAR:
717 case OP_QUERY:
718 case OP_MINQUERY:
719 case OP_POSQUERY:
720 tcode = set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
721 break;
722
723 /* Single-char upto sets the bit and tries the next */
724
725 case OP_UPTO:
726 case OP_MINUPTO:
727 case OP_POSUPTO:
728 tcode = set_table_bit(start_bits, tcode + 3, caseless, cd, utf8);
729 break;
730
731 /* At least one single char sets the bit and stops */
732
733 case OP_EXACT: /* Fall through */
734 tcode += 2;
735
736 case OP_CHAR:
737 case OP_CHARNC:
738 case OP_PLUS:
739 case OP_MINPLUS:
740 case OP_POSPLUS:
741 (void)set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
742 try_next = FALSE;
743 break;
744
745 /* Special spacing and line-terminating items. These recognize specific
746 lists of characters. The difference between VSPACE and ANYNL is that the
747 latter can match the two-character CRLF sequence, but that is not
748 relevant for finding the first character, so their code here is
749 identical. */
750
751 case OP_HSPACE:
752 SET_BIT(0x09);
753 SET_BIT(0x20);
754 if (utf8)
755 {
756 SET_BIT(0xC2); /* For U+00A0 */
757 SET_BIT(0xE1); /* For U+1680, U+180E */
758 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
759 SET_BIT(0xE3); /* For U+3000 */
760 }
761 else SET_BIT(0xA0);
762 try_next = FALSE;
763 break;
764
765 case OP_ANYNL:
766 case OP_VSPACE:
767 SET_BIT(0x0A);
768 SET_BIT(0x0B);
769 SET_BIT(0x0C);
770 SET_BIT(0x0D);
771 if (utf8)
772 {
773 SET_BIT(0xC2); /* For U+0085 */
774 SET_BIT(0xE2); /* For U+2028, U+2029 */
775 }
776 else SET_BIT(0x85);
777 try_next = FALSE;
778 break;
779
780 /* Single character types set the bits and stop. Note that if PCRE_UCP
781 is set, we do not see these op codes because \d etc are converted to
782 properties. Therefore, these apply in the case when only characters less
783 than 256 are recognized to match the types. */
784
785 case OP_NOT_DIGIT:
786 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
787 try_next = FALSE;
788 break;
789
790 case OP_DIGIT:
791 set_type_bits(start_bits, cbit_digit, table_limit, cd);
792 try_next = FALSE;
793 break;
794
795 /* The cbit_space table has vertical tab as whitespace; we have to
796 ensure it is set as not whitespace. */
797
798 case OP_NOT_WHITESPACE:
799 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
800 start_bits[1] |= 0x08;
801 try_next = FALSE;
802 break;
803
804 /* The cbit_space table has vertical tab as whitespace; we have to
805 not set it from the table. */
806
807 case OP_WHITESPACE:
808 c = start_bits[1]; /* Save in case it was already set */
809 set_type_bits(start_bits, cbit_space, table_limit, cd);
810 start_bits[1] = (start_bits[1] & ~0x08) | c;
811 try_next = FALSE;
812 break;
813
814 case OP_NOT_WORDCHAR:
815 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
816 try_next = FALSE;
817 break;
818
819 case OP_WORDCHAR:
820 set_type_bits(start_bits, cbit_word, table_limit, cd);
821 try_next = FALSE;
822 break;
823
824 /* One or more character type fudges the pointer and restarts, knowing
825 it will hit a single character type and stop there. */
826
827 case OP_TYPEPLUS:
828 case OP_TYPEMINPLUS:
829 case OP_TYPEPOSPLUS:
830 tcode++;
831 break;
832
833 case OP_TYPEEXACT:
834 tcode += 3;
835 break;
836
837 /* Zero or more repeats of character types set the bits and then
838 try again. */
839
840 case OP_TYPEUPTO:
841 case OP_TYPEMINUPTO:
842 case OP_TYPEPOSUPTO:
843 tcode += 2; /* Fall through */
844
845 case OP_TYPESTAR:
846 case OP_TYPEMINSTAR:
847 case OP_TYPEPOSSTAR:
848 case OP_TYPEQUERY:
849 case OP_TYPEMINQUERY:
850 case OP_TYPEPOSQUERY:
851 switch(tcode[1])
852 {
853 default:
854 case OP_ANY:
855 case OP_ALLANY:
856 return SSB_FAIL;
857
858 case OP_HSPACE:
859 SET_BIT(0x09);
860 SET_BIT(0x20);
861 if (utf8)
862 {
863 SET_BIT(0xC2); /* For U+00A0 */
864 SET_BIT(0xE1); /* For U+1680, U+180E */
865 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
866 SET_BIT(0xE3); /* For U+3000 */
867 }
868 else SET_BIT(0xA0);
869 break;
870
871 case OP_ANYNL:
872 case OP_VSPACE:
873 SET_BIT(0x0A);
874 SET_BIT(0x0B);
875 SET_BIT(0x0C);
876 SET_BIT(0x0D);
877 if (utf8)
878 {
879 SET_BIT(0xC2); /* For U+0085 */
880 SET_BIT(0xE2); /* For U+2028, U+2029 */
881 }
882 else SET_BIT(0x85);
883 break;
884
885 case OP_NOT_DIGIT:
886 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
887 break;
888
889 case OP_DIGIT:
890 set_type_bits(start_bits, cbit_digit, table_limit, cd);
891 break;
892
893 /* The cbit_space table has vertical tab as whitespace; we have to
894 ensure it gets set as not whitespace. */
895
896 case OP_NOT_WHITESPACE:
897 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
898 start_bits[1] |= 0x08;
899 break;
900
901 /* The cbit_space table has vertical tab as whitespace; we have to
902 avoid setting it. */
903
904 case OP_WHITESPACE:
905 c = start_bits[1]; /* Save in case it was already set */
906 set_type_bits(start_bits, cbit_space, table_limit, cd);
907 start_bits[1] = (start_bits[1] & ~0x08) | c;
908 break;
909
910 case OP_NOT_WORDCHAR:
911 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
912 break;
913
914 case OP_WORDCHAR:
915 set_type_bits(start_bits, cbit_word, table_limit, cd);
916 break;
917 }
918
919 tcode += 2;
920 break;
921
922 /* Character class where all the information is in a bit map: set the
923 bits and either carry on or not, according to the repeat count. If it was
924 a negative class, and we are operating with UTF-8 characters, any byte
925 with a value >= 0xc4 is a potentially valid starter because it starts a
926 character with a value > 255. */
927
928 case OP_NCLASS:
929 #ifdef SUPPORT_UTF8
930 if (utf8)
931 {
932 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
933 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
934 }
935 #endif
936 /* Fall through */
937
938 case OP_CLASS:
939 {
940 tcode++;
941
942 /* In UTF-8 mode, the bits in a bit map correspond to character
943 values, not to byte values. However, the bit map we are constructing is
944 for byte values. So we have to do a conversion for characters whose
945 value is > 127. In fact, there are only two possible starting bytes for
946 characters in the range 128 - 255. */
947
948 #ifdef SUPPORT_UTF8
949 if (utf8)
950 {
951 for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
952 for (c = 128; c < 256; c++)
953 {
954 if ((tcode[c/8] && (1 << (c&7))) != 0)
955 {
956 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
957 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
958 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
959 }
960 }
961 }
962
963 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
964
965 else
966 #endif
967 {
968 for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
969 }
970
971 /* Advance past the bit map, and act on what follows */
972
973 tcode += 32;
974 switch (*tcode)
975 {
976 case OP_CRSTAR:
977 case OP_CRMINSTAR:
978 case OP_CRQUERY:
979 case OP_CRMINQUERY:
980 tcode++;
981 break;
982
983 case OP_CRRANGE:
984 case OP_CRMINRANGE:
985 if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
986 else try_next = FALSE;
987 break;
988
989 default:
990 try_next = FALSE;
991 break;
992 }
993 }
994 break; /* End of bitmap class handling */
995
996 } /* End of switch */
997 } /* End of try_next loop */
998
999 code += GET(code, 1); /* Advance to next branch */
1000 }
1001 while (*code == OP_ALT);
1002 return yield;
1003 }
1004
1005
1006
1007 /*************************************************
1008 * Study a compiled expression *
1009 *************************************************/
1010
1011 /* This function is handed a compiled expression that it must study to produce
1012 information that will speed up the matching. It returns a pcre_extra block
1013 which then gets handed back to pcre_exec().
1014
1015 Arguments:
1016 re points to the compiled expression
1017 options contains option bits
1018 errorptr points to where to place error messages;
1019 set NULL unless error
1020
1021 Returns: pointer to a pcre_extra block, with study_data filled in and the
1022 appropriate flags set;
1023 NULL on error or if no optimization possible
1024 */
1025
1026 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1027 pcre_study(const pcre *external_re, int options, const char **errorptr)
1028 {
1029 int min;
1030 BOOL bits_set = FALSE;
1031 uschar start_bits[32];
1032 pcre_extra *extra;
1033 pcre_study_data *study;
1034 const uschar *tables;
1035 uschar *code;
1036 compile_data compile_block;
1037 const real_pcre *re = (const real_pcre *)external_re;
1038
1039 *errorptr = NULL;
1040
1041 if (re == NULL || re->magic_number != MAGIC_NUMBER)
1042 {
1043 *errorptr = "argument is not a compiled regular expression";
1044 return NULL;
1045 }
1046
1047 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1048 {
1049 *errorptr = "unknown or incorrect option bit(s) set";
1050 return NULL;
1051 }
1052
1053 code = (uschar *)re + re->name_table_offset +
1054 (re->name_count * re->name_entry_size);
1055
1056 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1057 a multiline pattern that matches only at "line starts", there is no point in
1058 seeking a list of starting bytes. */
1059
1060 if ((re->options & PCRE_ANCHORED) == 0 &&
1061 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1062 {
1063 /* Set the character tables in the block that is passed around */
1064
1065 tables = re->tables;
1066 if (tables == NULL)
1067 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1068 (void *)(&tables));
1069
1070 compile_block.lcc = tables + lcc_offset;
1071 compile_block.fcc = tables + fcc_offset;
1072 compile_block.cbits = tables + cbits_offset;
1073 compile_block.ctypes = tables + ctypes_offset;
1074
1075 /* See if we can find a fixed set of initial characters for the pattern. */
1076
1077 memset(start_bits, 0, 32 * sizeof(uschar));
1078 bits_set = set_start_bits(code, start_bits,
1079 (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
1080 &compile_block) == SSB_DONE;
1081 }
1082
1083 /* Find the minimum length of subject string. */
1084
1085 min = find_minlength(code, code, re->options);
1086
1087 /* Return NULL if no optimization is possible. */
1088
1089 if (!bits_set && min < 0) return NULL;
1090
1091 /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
1092 the latter, which is pointed to by the former, which may also get additional
1093 data set later by the calling program. At the moment, the size of
1094 pcre_study_data is fixed. We nevertheless save it in a field for returning via
1095 the pcre_fullinfo() function so that if it becomes variable in the future, we
1096 don't have to change that code. */
1097
1098 extra = (pcre_extra *)(pcre_malloc)
1099 (sizeof(pcre_extra) + sizeof(pcre_study_data));
1100
1101 if (extra == NULL)
1102 {
1103 *errorptr = "failed to get memory";
1104 return NULL;
1105 }
1106
1107 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1108 extra->flags = PCRE_EXTRA_STUDY_DATA;
1109 extra->study_data = study;
1110
1111 study->size = sizeof(pcre_study_data);
1112 study->flags = 0;
1113
1114 if (bits_set)
1115 {
1116 study->flags |= PCRE_STUDY_MAPPED;
1117 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1118 }
1119
1120 if (min >= 0)
1121 {
1122 study->flags |= PCRE_STUDY_MINLEN;
1123 study->minlength = min;
1124 }
1125
1126 return extra;
1127 }
1128
1129 /* End of pcre_study.c */

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