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Revision 524 - (show annotations)
Mon May 24 17:06:28 2010 UTC (5 years, 1 month ago) by ph10
File MIME type: text/plain
File size: 29768 byte(s)
Error occurred while calculating annotation data.
Make pcre_study() recognize \h, \v, and \R.
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 case OP_THEN_ARG:
423 cc += _pcre_OP_lengths[op] + cc[1];
424 break;
425
426 /* For the record, these are the opcodes that are matched by "default":
427 OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
428 OP_THEN. */
429
430 default:
431 cc += _pcre_OP_lengths[op];
432 break;
433 }
434 }
435 /* Control never gets here */
436 }
437
438
439
440 /*************************************************
441 * Set a bit and maybe its alternate case *
442 *************************************************/
443
444 /* Given a character, set its first byte's bit in the table, and also the
445 corresponding bit for the other version of a letter if we are caseless. In
446 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
447 when Unicode property support is available.
448
449 Arguments:
450 start_bits points to the bit map
451 p points to the character
452 caseless the caseless flag
453 cd the block with char table pointers
454 utf8 TRUE for UTF-8 mode
455
456 Returns: pointer after the character
457 */
458
459 static const uschar *
460 set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
461 compile_data *cd, BOOL utf8)
462 {
463 unsigned int c = *p;
464
465 SET_BIT(c);
466
467 #ifdef SUPPORT_UTF8
468 if (utf8 && c > 127)
469 {
470 GETCHARINC(c, p);
471 #ifdef SUPPORT_UCP
472 if (caseless)
473 {
474 uschar buff[8];
475 c = UCD_OTHERCASE(c);
476 (void)_pcre_ord2utf8(c, buff);
477 SET_BIT(buff[0]);
478 }
479 #endif
480 return p;
481 }
482 #endif
483
484 /* Not UTF-8 mode, or character is less than 127. */
485
486 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
487 return p + 1;
488 }
489
490
491
492 /*************************************************
493 * Create bitmap of starting bytes *
494 *************************************************/
495
496 /* This function scans a compiled unanchored expression recursively and
497 attempts to build a bitmap of the set of possible starting bytes. As time goes
498 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
499 useful for parenthesized groups in patterns such as (a*)b where the group
500 provides some optional starting bytes but scanning must continue at the outer
501 level to find at least one mandatory byte. At the outermost level, this
502 function fails unless the result is SSB_DONE.
503
504 Arguments:
505 code points to an expression
506 start_bits points to a 32-byte table, initialized to 0
507 caseless the current state of the caseless flag
508 utf8 TRUE if in UTF-8 mode
509 cd the block with char table pointers
510
511 Returns: SSB_FAIL => Failed to find any starting bytes
512 SSB_DONE => Found mandatory starting bytes
513 SSB_CONTINUE => Found optional starting bytes
514 */
515
516 static int
517 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
518 BOOL utf8, compile_data *cd)
519 {
520 register int c;
521 int yield = SSB_DONE;
522
523 #if 0
524 /* ========================================================================= */
525 /* The following comment and code was inserted in January 1999. In May 2006,
526 when it was observed to cause compiler warnings about unused values, I took it
527 out again. If anybody is still using OS/2, they will have to put it back
528 manually. */
529
530 /* This next statement and the later reference to dummy are here in order to
531 trick the optimizer of the IBM C compiler for OS/2 into generating correct
532 code. Apparently IBM isn't going to fix the problem, and we would rather not
533 disable optimization (in this module it actually makes a big difference, and
534 the pcre module can use all the optimization it can get). */
535
536 volatile int dummy;
537 /* ========================================================================= */
538 #endif
539
540 do
541 {
542 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
543 BOOL try_next = TRUE;
544
545 while (try_next) /* Loop for items in this branch */
546 {
547 int rc;
548 switch(*tcode)
549 {
550 /* Fail if we reach something we don't understand */
551
552 default:
553 return SSB_FAIL;
554
555 /* If we hit a bracket or a positive lookahead assertion, recurse to set
556 bits from within the subpattern. If it can't find anything, we have to
557 give up. If it finds some mandatory character(s), we are done for this
558 branch. Otherwise, carry on scanning after the subpattern. */
559
560 case OP_BRA:
561 case OP_SBRA:
562 case OP_CBRA:
563 case OP_SCBRA:
564 case OP_ONCE:
565 case OP_ASSERT:
566 rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
567 if (rc == SSB_FAIL) return SSB_FAIL;
568 if (rc == SSB_DONE) try_next = FALSE; else
569 {
570 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
571 tcode += 1 + LINK_SIZE;
572 }
573 break;
574
575 /* If we hit ALT or KET, it means we haven't found anything mandatory in
576 this branch, though we might have found something optional. For ALT, we
577 continue with the next alternative, but we have to arrange that the final
578 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
579 return SSB_CONTINUE: if this is the top level, that indicates failure,
580 but after a nested subpattern, it causes scanning to continue. */
581
582 case OP_ALT:
583 yield = SSB_CONTINUE;
584 try_next = FALSE;
585 break;
586
587 case OP_KET:
588 case OP_KETRMAX:
589 case OP_KETRMIN:
590 return SSB_CONTINUE;
591
592 /* Skip over callout */
593
594 case OP_CALLOUT:
595 tcode += 2 + 2*LINK_SIZE;
596 break;
597
598 /* Skip over lookbehind and negative lookahead assertions */
599
600 case OP_ASSERT_NOT:
601 case OP_ASSERTBACK:
602 case OP_ASSERTBACK_NOT:
603 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
604 tcode += 1 + LINK_SIZE;
605 break;
606
607 /* Skip over an option setting, changing the caseless flag */
608
609 case OP_OPT:
610 caseless = (tcode[1] & PCRE_CASELESS) != 0;
611 tcode += 2;
612 break;
613
614 /* BRAZERO does the bracket, but carries on. */
615
616 case OP_BRAZERO:
617 case OP_BRAMINZERO:
618 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
619 return SSB_FAIL;
620 /* =========================================================================
621 See the comment at the head of this function concerning the next line,
622 which was an old fudge for the benefit of OS/2.
623 dummy = 1;
624 ========================================================================= */
625 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
626 tcode += 1 + LINK_SIZE;
627 break;
628
629 /* SKIPZERO skips the bracket. */
630
631 case OP_SKIPZERO:
632 tcode++;
633 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
634 tcode += 1 + LINK_SIZE;
635 break;
636
637 /* Single-char * or ? sets the bit and tries the next item */
638
639 case OP_STAR:
640 case OP_MINSTAR:
641 case OP_POSSTAR:
642 case OP_QUERY:
643 case OP_MINQUERY:
644 case OP_POSQUERY:
645 tcode = set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
646 break;
647
648 /* Single-char upto sets the bit and tries the next */
649
650 case OP_UPTO:
651 case OP_MINUPTO:
652 case OP_POSUPTO:
653 tcode = set_table_bit(start_bits, tcode + 3, caseless, cd, utf8);
654 break;
655
656 /* At least one single char sets the bit and stops */
657
658 case OP_EXACT: /* Fall through */
659 tcode += 2;
660
661 case OP_CHAR:
662 case OP_CHARNC:
663 case OP_PLUS:
664 case OP_MINPLUS:
665 case OP_POSPLUS:
666 (void)set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
667 try_next = FALSE;
668 break;
669
670 /* Special spacing and line-terminating items. These recognize specific
671 lists of characters. The difference between VSPACE and ANYNL is that the
672 latter can match the two-character CRLF sequence, but that is not
673 relevant for finding the first character, so their code here is
674 identical. */
675
676 case OP_HSPACE:
677 SET_BIT(0x09);
678 SET_BIT(0x20);
679 SET_BIT(0xA0);
680 if (utf8)
681 {
682 SET_BIT(0xE1); /* For U+1680, U+180E */
683 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
684 SET_BIT(0xE3); /* For U+3000 */
685 }
686 try_next = FALSE;
687 break;
688
689 case OP_ANYNL:
690 case OP_VSPACE:
691 SET_BIT(0x0A);
692 SET_BIT(0x0B);
693 SET_BIT(0x0C);
694 SET_BIT(0x0D);
695 SET_BIT(0x85);
696 if (utf8) SET_BIT(0xE2); /* For U+2028, U+2029 */
697 try_next = FALSE;
698 break;
699
700 /* Single character types set the bits and stop. Note that if PCRE_UCP
701 is set, we do not see these op codes because \d etc are converted to
702 properties. Therefore, these apply in the case when only ASCII characters
703 are recognized to match the types. */
704
705 case OP_NOT_DIGIT:
706 for (c = 0; c < 32; c++)
707 start_bits[c] |= ~cd->cbits[c+cbit_digit];
708 try_next = FALSE;
709 break;
710
711 case OP_DIGIT:
712 for (c = 0; c < 32; c++)
713 start_bits[c] |= cd->cbits[c+cbit_digit];
714 try_next = FALSE;
715 break;
716
717 /* The cbit_space table has vertical tab as whitespace; we have to
718 discard it. */
719
720 case OP_NOT_WHITESPACE:
721 for (c = 0; c < 32; c++)
722 {
723 int d = cd->cbits[c+cbit_space];
724 if (c == 1) d &= ~0x08;
725 start_bits[c] |= ~d;
726 }
727 try_next = FALSE;
728 break;
729
730 /* The cbit_space table has vertical tab as whitespace; we have to
731 discard it. */
732
733 case OP_WHITESPACE:
734 for (c = 0; c < 32; c++)
735 {
736 int d = cd->cbits[c+cbit_space];
737 if (c == 1) d &= ~0x08;
738 start_bits[c] |= d;
739 }
740 try_next = FALSE;
741 break;
742
743 case OP_NOT_WORDCHAR:
744 for (c = 0; c < 32; c++)
745 start_bits[c] |= ~cd->cbits[c+cbit_word];
746 try_next = FALSE;
747 break;
748
749 case OP_WORDCHAR:
750 for (c = 0; c < 32; c++)
751 start_bits[c] |= cd->cbits[c+cbit_word];
752 try_next = FALSE;
753 break;
754
755 /* One or more character type fudges the pointer and restarts, knowing
756 it will hit a single character type and stop there. */
757
758 case OP_TYPEPLUS:
759 case OP_TYPEMINPLUS:
760 case OP_TYPEPOSPLUS:
761 tcode++;
762 break;
763
764 case OP_TYPEEXACT:
765 tcode += 3;
766 break;
767
768 /* Zero or more repeats of character types set the bits and then
769 try again. */
770
771 case OP_TYPEUPTO:
772 case OP_TYPEMINUPTO:
773 case OP_TYPEPOSUPTO:
774 tcode += 2; /* Fall through */
775
776 case OP_TYPESTAR:
777 case OP_TYPEMINSTAR:
778 case OP_TYPEPOSSTAR:
779 case OP_TYPEQUERY:
780 case OP_TYPEMINQUERY:
781 case OP_TYPEPOSQUERY:
782 switch(tcode[1])
783 {
784 default:
785 case OP_ANY:
786 case OP_ALLANY:
787 return SSB_FAIL;
788
789 case OP_HSPACE:
790 SET_BIT(0x09);
791 SET_BIT(0x20);
792 SET_BIT(0xA0);
793 if (utf8)
794 {
795 SET_BIT(0xE1); /* For U+1680, U+180E */
796 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
797 SET_BIT(0xE3); /* For U+3000 */
798 }
799 break;
800
801 case OP_ANYNL:
802 case OP_VSPACE:
803 SET_BIT(0x0A);
804 SET_BIT(0x0B);
805 SET_BIT(0x0C);
806 SET_BIT(0x0D);
807 SET_BIT(0x85);
808 if (utf8) SET_BIT(0xE2); /* For U+2028, U+2029 */
809 break;
810
811 case OP_NOT_DIGIT:
812 for (c = 0; c < 32; c++)
813 start_bits[c] |= ~cd->cbits[c+cbit_digit];
814 break;
815
816 case OP_DIGIT:
817 for (c = 0; c < 32; c++)
818 start_bits[c] |= cd->cbits[c+cbit_digit];
819 break;
820
821 /* The cbit_space table has vertical tab as whitespace; we have to
822 discard it. */
823
824 case OP_NOT_WHITESPACE:
825 for (c = 0; c < 32; c++)
826 {
827 int d = cd->cbits[c+cbit_space];
828 if (c == 1) d &= ~0x08;
829 start_bits[c] |= ~d;
830 }
831 break;
832
833 /* The cbit_space table has vertical tab as whitespace; we have to
834 discard it. */
835
836 case OP_WHITESPACE:
837 for (c = 0; c < 32; c++)
838 {
839 int d = cd->cbits[c+cbit_space];
840 if (c == 1) d &= ~0x08;
841 start_bits[c] |= d;
842 }
843 break;
844
845 case OP_NOT_WORDCHAR:
846 for (c = 0; c < 32; c++)
847 start_bits[c] |= ~cd->cbits[c+cbit_word];
848 break;
849
850 case OP_WORDCHAR:
851 for (c = 0; c < 32; c++)
852 start_bits[c] |= cd->cbits[c+cbit_word];
853 break;
854 }
855
856 tcode += 2;
857 break;
858
859 /* Character class where all the information is in a bit map: set the
860 bits and either carry on or not, according to the repeat count. If it was
861 a negative class, and we are operating with UTF-8 characters, any byte
862 with a value >= 0xc4 is a potentially valid starter because it starts a
863 character with a value > 255. */
864
865 case OP_NCLASS:
866 #ifdef SUPPORT_UTF8
867 if (utf8)
868 {
869 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
870 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
871 }
872 #endif
873 /* Fall through */
874
875 case OP_CLASS:
876 {
877 tcode++;
878
879 /* In UTF-8 mode, the bits in a bit map correspond to character
880 values, not to byte values. However, the bit map we are constructing is
881 for byte values. So we have to do a conversion for characters whose
882 value is > 127. In fact, there are only two possible starting bytes for
883 characters in the range 128 - 255. */
884
885 #ifdef SUPPORT_UTF8
886 if (utf8)
887 {
888 for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
889 for (c = 128; c < 256; c++)
890 {
891 if ((tcode[c/8] && (1 << (c&7))) != 0)
892 {
893 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
894 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
895 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
896 }
897 }
898 }
899
900 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
901
902 else
903 #endif
904 {
905 for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
906 }
907
908 /* Advance past the bit map, and act on what follows */
909
910 tcode += 32;
911 switch (*tcode)
912 {
913 case OP_CRSTAR:
914 case OP_CRMINSTAR:
915 case OP_CRQUERY:
916 case OP_CRMINQUERY:
917 tcode++;
918 break;
919
920 case OP_CRRANGE:
921 case OP_CRMINRANGE:
922 if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
923 else try_next = FALSE;
924 break;
925
926 default:
927 try_next = FALSE;
928 break;
929 }
930 }
931 break; /* End of bitmap class handling */
932
933 } /* End of switch */
934 } /* End of try_next loop */
935
936 code += GET(code, 1); /* Advance to next branch */
937 }
938 while (*code == OP_ALT);
939 return yield;
940 }
941
942
943
944 /*************************************************
945 * Study a compiled expression *
946 *************************************************/
947
948 /* This function is handed a compiled expression that it must study to produce
949 information that will speed up the matching. It returns a pcre_extra block
950 which then gets handed back to pcre_exec().
951
952 Arguments:
953 re points to the compiled expression
954 options contains option bits
955 errorptr points to where to place error messages;
956 set NULL unless error
957
958 Returns: pointer to a pcre_extra block, with study_data filled in and the
959 appropriate flags set;
960 NULL on error or if no optimization possible
961 */
962
963 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
964 pcre_study(const pcre *external_re, int options, const char **errorptr)
965 {
966 int min;
967 BOOL bits_set = FALSE;
968 uschar start_bits[32];
969 pcre_extra *extra;
970 pcre_study_data *study;
971 const uschar *tables;
972 uschar *code;
973 compile_data compile_block;
974 const real_pcre *re = (const real_pcre *)external_re;
975
976 *errorptr = NULL;
977
978 if (re == NULL || re->magic_number != MAGIC_NUMBER)
979 {
980 *errorptr = "argument is not a compiled regular expression";
981 return NULL;
982 }
983
984 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
985 {
986 *errorptr = "unknown or incorrect option bit(s) set";
987 return NULL;
988 }
989
990 code = (uschar *)re + re->name_table_offset +
991 (re->name_count * re->name_entry_size);
992
993 /* For an anchored pattern, or an unanchored pattern that has a first char, or
994 a multiline pattern that matches only at "line starts", there is no point in
995 seeking a list of starting bytes. */
996
997 if ((re->options & PCRE_ANCHORED) == 0 &&
998 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
999 {
1000 /* Set the character tables in the block that is passed around */
1001
1002 tables = re->tables;
1003 if (tables == NULL)
1004 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1005 (void *)(&tables));
1006
1007 compile_block.lcc = tables + lcc_offset;
1008 compile_block.fcc = tables + fcc_offset;
1009 compile_block.cbits = tables + cbits_offset;
1010 compile_block.ctypes = tables + ctypes_offset;
1011
1012 /* See if we can find a fixed set of initial characters for the pattern. */
1013
1014 memset(start_bits, 0, 32 * sizeof(uschar));
1015 bits_set = set_start_bits(code, start_bits,
1016 (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
1017 &compile_block) == SSB_DONE;
1018 }
1019
1020 /* Find the minimum length of subject string. */
1021
1022 min = find_minlength(code, code, re->options);
1023
1024 /* Return NULL if no optimization is possible. */
1025
1026 if (!bits_set && min < 0) return NULL;
1027
1028 /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
1029 the latter, which is pointed to by the former, which may also get additional
1030 data set later by the calling program. At the moment, the size of
1031 pcre_study_data is fixed. We nevertheless save it in a field for returning via
1032 the pcre_fullinfo() function so that if it becomes variable in the future, we
1033 don't have to change that code. */
1034
1035 extra = (pcre_extra *)(pcre_malloc)
1036 (sizeof(pcre_extra) + sizeof(pcre_study_data));
1037
1038 if (extra == NULL)
1039 {
1040 *errorptr = "failed to get memory";
1041 return NULL;
1042 }
1043
1044 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1045 extra->flags = PCRE_EXTRA_STUDY_DATA;
1046 extra->study_data = study;
1047
1048 study->size = sizeof(pcre_study_data);
1049 study->flags = 0;
1050
1051 if (bits_set)
1052 {
1053 study->flags |= PCRE_STUDY_MAPPED;
1054 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1055 }
1056
1057 if (min >= 0)
1058 {
1059 study->flags |= PCRE_STUDY_MINLEN;
1060 study->minlength = min;
1061 }
1062
1063 return extra;
1064 }
1065
1066 /* End of pcre_study.c */

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