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

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Revision 806 - (show annotations)
Thu Dec 15 11:57:39 2011 UTC (9 years, 9 months ago) by zherczeg
File MIME type: text/plain
File size: 42113 byte(s)
lcc and inline printint.c fixes
1 /*************************************************
2 * Perl-Compatible Regular Expressions *
3 *************************************************/
4
5 /* PCRE is a library of functions to support regular expressions whose syntax
6 and semantics are as close as possible to those of the Perl 5 language.
7
8 Written by Philip Hazel
9 Copyright (c) 1997-2010 University of Cambridge
10
11 -----------------------------------------------------------------------------
12 Redistribution and use in source and binary forms, with or without
13 modification, are permitted provided that the following conditions are met:
14
15 * Redistributions of source code must retain the above copyright notice,
16 this list of conditions and the following disclaimer.
17
18 * Redistributions in binary form must reproduce the above copyright
19 notice, this list of conditions and the following disclaimer in the
20 documentation and/or other materials provided with the distribution.
21
22 * Neither the name of the University of Cambridge nor the names of its
23 contributors may be used to endorse or promote products derived from
24 this software without specific prior written permission.
25
26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
27 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
30 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 POSSIBILITY OF SUCH DAMAGE.
37 -----------------------------------------------------------------------------
38 */
39
40
41 /* This module contains the external function pcre_study(), along with local
42 supporting functions. */
43
44
45 #ifdef HAVE_CONFIG_H
46 #include "config.h"
47 #endif
48
49 #include "pcre_internal.h"
50
51 #define SET_BIT(c) start_bits[c/8] |= (1 << (c&7))
52
53 /* Returns from set_start_bits() */
54
55 enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE, SSB_UNKNOWN };
56
57
58
59 /*************************************************
60 * Find the minimum subject length for a group *
61 *************************************************/
62
63 /* Scan a parenthesized group and compute the minimum length of subject that
64 is needed to match it. This is a lower bound; it does not mean there is a
65 string of that length that matches. In UTF8 mode, the result is in characters
66 rather than bytes.
67
68 Arguments:
69 code pointer to start of group (the bracket)
70 startcode pointer to start of the whole pattern
71 options the compiling options
72 int RECURSE depth
73
74 Returns: the minimum length
75 -1 if \C in UTF-8 mode or (*ACCEPT) was encountered
76 -2 internal error (missing capturing bracket)
77 -3 internal error (opcode not listed)
78 */
79
80 static int
81 find_minlength(const pcre_uchar *code, const pcre_uchar *startcode, int options,
82 int recurse_depth)
83 {
84 int length = -1;
85 /* PCRE_UTF16 has the same value as PCRE_UTF8. */
86 BOOL utf = (options & PCRE_UTF8) != 0;
87 BOOL had_recurse = FALSE;
88 register int branchlength = 0;
89 register pcre_uchar *cc = (pcre_uchar *)code + 1 + LINK_SIZE;
90
91 if (*code == OP_CBRA || *code == OP_SCBRA ||
92 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += IMM2_SIZE;
93
94 /* Scan along the opcodes for this branch. If we get to the end of the
95 branch, check the length against that of the other branches. */
96
97 for (;;)
98 {
99 int d, min;
100 pcre_uchar *cs, *ce;
101 register int op = *cc;
102
103 switch (op)
104 {
105 case OP_COND:
106 case OP_SCOND:
107
108 /* If there is only one branch in a condition, the implied branch has zero
109 length, so we don't add anything. This covers the DEFINE "condition"
110 automatically. */
111
112 cs = cc + GET(cc, 1);
113 if (*cs != OP_ALT)
114 {
115 cc = cs + 1 + LINK_SIZE;
116 break;
117 }
118
119 /* Otherwise we can fall through and treat it the same as any other
120 subpattern. */
121
122 case OP_CBRA:
123 case OP_SCBRA:
124 case OP_BRA:
125 case OP_SBRA:
126 case OP_CBRAPOS:
127 case OP_SCBRAPOS:
128 case OP_BRAPOS:
129 case OP_SBRAPOS:
130 case OP_ONCE:
131 case OP_ONCE_NC:
132 d = find_minlength(cc, startcode, options, recurse_depth);
133 if (d < 0) return d;
134 branchlength += d;
135 do cc += GET(cc, 1); while (*cc == OP_ALT);
136 cc += 1 + LINK_SIZE;
137 break;
138
139 /* ACCEPT makes things far too complicated; we have to give up. */
140
141 case OP_ACCEPT:
142 case OP_ASSERT_ACCEPT:
143 return -1;
144
145 /* Reached end of a branch; if it's a ket it is the end of a nested
146 call. If it's ALT it is an alternation in a nested call. If it is END it's
147 the end of the outer call. All can be handled by the same code. If an
148 ACCEPT was previously encountered, use the length that was in force at that
149 time, and pass back the shortest ACCEPT length. */
150
151 case OP_ALT:
152 case OP_KET:
153 case OP_KETRMAX:
154 case OP_KETRMIN:
155 case OP_KETRPOS:
156 case OP_END:
157 if (length < 0 || (!had_recurse && branchlength < length))
158 length = branchlength;
159 if (op != OP_ALT) return length;
160 cc += 1 + LINK_SIZE;
161 branchlength = 0;
162 had_recurse = FALSE;
163 break;
164
165 /* Skip over assertive subpatterns */
166
167 case OP_ASSERT:
168 case OP_ASSERT_NOT:
169 case OP_ASSERTBACK:
170 case OP_ASSERTBACK_NOT:
171 do cc += GET(cc, 1); while (*cc == OP_ALT);
172 /* Fall through */
173
174 /* Skip over things that don't match chars */
175
176 case OP_REVERSE:
177 case OP_CREF:
178 case OP_NCREF:
179 case OP_RREF:
180 case OP_NRREF:
181 case OP_DEF:
182 case OP_CALLOUT:
183 case OP_SOD:
184 case OP_SOM:
185 case OP_EOD:
186 case OP_EODN:
187 case OP_CIRC:
188 case OP_CIRCM:
189 case OP_DOLL:
190 case OP_DOLLM:
191 case OP_NOT_WORD_BOUNDARY:
192 case OP_WORD_BOUNDARY:
193 cc += PRIV(OP_lengths)[*cc];
194 break;
195
196 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
197
198 case OP_BRAZERO:
199 case OP_BRAMINZERO:
200 case OP_BRAPOSZERO:
201 case OP_SKIPZERO:
202 cc += PRIV(OP_lengths)[*cc];
203 do cc += GET(cc, 1); while (*cc == OP_ALT);
204 cc += 1 + LINK_SIZE;
205 break;
206
207 /* Handle literal characters and + repetitions */
208
209 case OP_CHAR:
210 case OP_CHARI:
211 case OP_NOT:
212 case OP_NOTI:
213 case OP_PLUS:
214 case OP_PLUSI:
215 case OP_MINPLUS:
216 case OP_MINPLUSI:
217 case OP_POSPLUS:
218 case OP_POSPLUSI:
219 case OP_NOTPLUS:
220 case OP_NOTPLUSI:
221 case OP_NOTMINPLUS:
222 case OP_NOTMINPLUSI:
223 case OP_NOTPOSPLUS:
224 case OP_NOTPOSPLUSI:
225 branchlength++;
226 cc += 2;
227 #ifdef SUPPORT_UTF
228 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
229 #endif
230 break;
231
232 case OP_TYPEPLUS:
233 case OP_TYPEMINPLUS:
234 case OP_TYPEPOSPLUS:
235 branchlength++;
236 cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
237 break;
238
239 /* Handle exact repetitions. The count is already in characters, but we
240 need to skip over a multibyte character in UTF8 mode. */
241
242 case OP_EXACT:
243 case OP_EXACTI:
244 case OP_NOTEXACT:
245 case OP_NOTEXACTI:
246 branchlength += GET2(cc,1);
247 cc += 2 + IMM2_SIZE;
248 #ifdef SUPPORT_UTF
249 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
250 #endif
251 break;
252
253 case OP_TYPEEXACT:
254 branchlength += GET2(cc,1);
255 cc += 2 + IMM2_SIZE + ((cc[1 + IMM2_SIZE] == OP_PROP
256 || cc[1 + IMM2_SIZE] == OP_NOTPROP)? 2 : 0);
257 break;
258
259 /* Handle single-char non-literal matchers */
260
261 case OP_PROP:
262 case OP_NOTPROP:
263 cc += 2;
264 /* Fall through */
265
266 case OP_NOT_DIGIT:
267 case OP_DIGIT:
268 case OP_NOT_WHITESPACE:
269 case OP_WHITESPACE:
270 case OP_NOT_WORDCHAR:
271 case OP_WORDCHAR:
272 case OP_ANY:
273 case OP_ALLANY:
274 case OP_EXTUNI:
275 case OP_HSPACE:
276 case OP_NOT_HSPACE:
277 case OP_VSPACE:
278 case OP_NOT_VSPACE:
279 branchlength++;
280 cc++;
281 break;
282
283 /* "Any newline" might match two characters, but it also might match just
284 one. */
285
286 case OP_ANYNL:
287 branchlength += 1;
288 cc++;
289 break;
290
291 /* The single-byte matcher means we can't proceed in UTF-8 mode. (In
292 non-UTF-8 mode \C will actually be turned into OP_ALLANY, so won't ever
293 appear, but leave the code, just in case.) */
294
295 case OP_ANYBYTE:
296 #ifdef SUPPORT_UTF
297 if (utf) return -1;
298 #endif
299 branchlength++;
300 cc++;
301 break;
302
303 /* For repeated character types, we have to test for \p and \P, which have
304 an extra two bytes of parameters. */
305
306 case OP_TYPESTAR:
307 case OP_TYPEMINSTAR:
308 case OP_TYPEQUERY:
309 case OP_TYPEMINQUERY:
310 case OP_TYPEPOSSTAR:
311 case OP_TYPEPOSQUERY:
312 if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
313 cc += PRIV(OP_lengths)[op];
314 break;
315
316 case OP_TYPEUPTO:
317 case OP_TYPEMINUPTO:
318 case OP_TYPEPOSUPTO:
319 if (cc[1 + IMM2_SIZE] == OP_PROP
320 || cc[1 + IMM2_SIZE] == OP_NOTPROP) cc += 2;
321 cc += PRIV(OP_lengths)[op];
322 break;
323
324 /* Check a class for variable quantification */
325
326 #if defined SUPPORT_UTF || !defined COMPILE_PCRE8
327 case OP_XCLASS:
328 cc += GET(cc, 1) - PRIV(OP_lengths)[OP_CLASS];
329 /* Fall through */
330 #endif
331
332 case OP_CLASS:
333 case OP_NCLASS:
334 cc += PRIV(OP_lengths)[OP_CLASS];
335
336 switch (*cc)
337 {
338 case OP_CRPLUS:
339 case OP_CRMINPLUS:
340 branchlength++;
341 /* Fall through */
342
343 case OP_CRSTAR:
344 case OP_CRMINSTAR:
345 case OP_CRQUERY:
346 case OP_CRMINQUERY:
347 cc++;
348 break;
349
350 case OP_CRRANGE:
351 case OP_CRMINRANGE:
352 branchlength += GET2(cc,1);
353 cc += 1 + 2 * IMM2_SIZE;
354 break;
355
356 default:
357 branchlength++;
358 break;
359 }
360 break;
361
362 /* Backreferences and subroutine calls are treated in the same way: we find
363 the minimum length for the subpattern. A recursion, however, causes an
364 a flag to be set that causes the length of this branch to be ignored. The
365 logic is that a recursion can only make sense if there is another
366 alternation that stops the recursing. That will provide the minimum length
367 (when no recursion happens). A backreference within the group that it is
368 referencing behaves in the same way.
369
370 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
371 matches an empty string (by default it causes a matching failure), so in
372 that case we must set the minimum length to zero. */
373
374 case OP_REF:
375 case OP_REFI:
376 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
377 {
378 ce = cs = (pcre_uchar *)PRIV(find_bracket)(startcode, utf, GET2(cc, 1));
379 if (cs == NULL) return -2;
380 do ce += GET(ce, 1); while (*ce == OP_ALT);
381 if (cc > cs && cc < ce)
382 {
383 d = 0;
384 had_recurse = TRUE;
385 }
386 else
387 {
388 d = find_minlength(cs, startcode, options, recurse_depth);
389 }
390 }
391 else d = 0;
392 cc += 1 + IMM2_SIZE;
393
394 /* Handle repeated back references */
395
396 switch (*cc)
397 {
398 case OP_CRSTAR:
399 case OP_CRMINSTAR:
400 case OP_CRQUERY:
401 case OP_CRMINQUERY:
402 min = 0;
403 cc++;
404 break;
405
406 case OP_CRPLUS:
407 case OP_CRMINPLUS:
408 min = 1;
409 cc++;
410 break;
411
412 case OP_CRRANGE:
413 case OP_CRMINRANGE:
414 min = GET2(cc, 1);
415 cc += 1 + 2 * IMM2_SIZE;
416 break;
417
418 default:
419 min = 1;
420 break;
421 }
422
423 branchlength += min * d;
424 break;
425
426 /* We can easily detect direct recursion, but not mutual recursion. This is
427 caught by a recursion depth count. */
428
429 case OP_RECURSE:
430 cs = ce = (pcre_uchar *)startcode + GET(cc, 1);
431 do ce += GET(ce, 1); while (*ce == OP_ALT);
432 if ((cc > cs && cc < ce) || recurse_depth > 10)
433 had_recurse = TRUE;
434 else
435 {
436 branchlength += find_minlength(cs, startcode, options, recurse_depth + 1);
437 }
438 cc += 1 + LINK_SIZE;
439 break;
440
441 /* Anything else does not or need not match a character. We can get the
442 item's length from the table, but for those that can match zero occurrences
443 of a character, we must take special action for UTF-8 characters. As it
444 happens, the "NOT" versions of these opcodes are used at present only for
445 ASCII characters, so they could be omitted from this list. However, in
446 future that may change, so we include them here so as not to leave a
447 gotcha for a future maintainer. */
448
449 case OP_UPTO:
450 case OP_UPTOI:
451 case OP_NOTUPTO:
452 case OP_NOTUPTOI:
453 case OP_MINUPTO:
454 case OP_MINUPTOI:
455 case OP_NOTMINUPTO:
456 case OP_NOTMINUPTOI:
457 case OP_POSUPTO:
458 case OP_POSUPTOI:
459 case OP_NOTPOSUPTO:
460 case OP_NOTPOSUPTOI:
461
462 case OP_STAR:
463 case OP_STARI:
464 case OP_NOTSTAR:
465 case OP_NOTSTARI:
466 case OP_MINSTAR:
467 case OP_MINSTARI:
468 case OP_NOTMINSTAR:
469 case OP_NOTMINSTARI:
470 case OP_POSSTAR:
471 case OP_POSSTARI:
472 case OP_NOTPOSSTAR:
473 case OP_NOTPOSSTARI:
474
475 case OP_QUERY:
476 case OP_QUERYI:
477 case OP_NOTQUERY:
478 case OP_NOTQUERYI:
479 case OP_MINQUERY:
480 case OP_MINQUERYI:
481 case OP_NOTMINQUERY:
482 case OP_NOTMINQUERYI:
483 case OP_POSQUERY:
484 case OP_POSQUERYI:
485 case OP_NOTPOSQUERY:
486 case OP_NOTPOSQUERYI:
487
488 cc += PRIV(OP_lengths)[op];
489 #ifdef SUPPORT_UTF
490 if (utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
491 #endif
492 break;
493
494 /* Skip these, but we need to add in the name length. */
495
496 case OP_MARK:
497 case OP_PRUNE_ARG:
498 case OP_SKIP_ARG:
499 case OP_THEN_ARG:
500 cc += PRIV(OP_lengths)[op] + cc[1];
501 break;
502
503 /* The remaining opcodes are just skipped over. */
504
505 case OP_CLOSE:
506 case OP_COMMIT:
507 case OP_FAIL:
508 case OP_PRUNE:
509 case OP_SET_SOM:
510 case OP_SKIP:
511 case OP_THEN:
512 cc += PRIV(OP_lengths)[op];
513 break;
514
515 /* This should not occur: we list all opcodes explicitly so that when
516 new ones get added they are properly considered. */
517
518 default:
519 return -3;
520 }
521 }
522 /* Control never gets here */
523 }
524
525
526
527 /*************************************************
528 * Set a bit and maybe its alternate case *
529 *************************************************/
530
531 /* Given a character, set its first byte's bit in the table, and also the
532 corresponding bit for the other version of a letter if we are caseless. In
533 UTF-8 mode, for characters greater than 127, we can only do the caseless thing
534 when Unicode property support is available.
535
536 Arguments:
537 start_bits points to the bit map
538 p points to the character
539 caseless the caseless flag
540 cd the block with char table pointers
541 utf TRUE for UTF-8 / UTF-16 mode
542
543 Returns: pointer after the character
544 */
545
546 static const pcre_uchar *
547 set_table_bit(pcre_uint8 *start_bits, const pcre_uchar *p, BOOL caseless,
548 compile_data *cd, BOOL utf)
549 {
550 unsigned int c = *p;
551
552 #ifdef COMPILE_PCRE8
553 SET_BIT(c);
554
555 #ifdef SUPPORT_UTF
556 if (utf && c > 127)
557 {
558 GETCHARINC(c, p);
559 #ifdef SUPPORT_UCP
560 if (caseless)
561 {
562 pcre_uchar buff[6];
563 c = UCD_OTHERCASE(c);
564 (void)PRIV(ord2utf)(c, buff);
565 SET_BIT(buff[0]);
566 }
567 #endif
568 return p;
569 }
570 #endif
571
572 /* Not UTF-8 mode, or character is less than 127. */
573
574 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
575 return p + 1;
576 #endif
577
578 #ifdef COMPILE_PCRE16
579 if (c > 0xff)
580 {
581 c = 0xff;
582 caseless = FALSE;
583 }
584 SET_BIT(c);
585
586 #ifdef SUPPORT_UTF
587 if (utf && c > 127)
588 {
589 GETCHARINC(c, p);
590 #ifdef SUPPORT_UCP
591 if (caseless)
592 {
593 c = UCD_OTHERCASE(c);
594 if (c > 0xff)
595 c = 0xff;
596 SET_BIT(c);
597 }
598 #endif
599 return p;
600 }
601 #endif
602
603 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
604 return p + 1;
605 #endif
606 }
607
608
609
610 /*************************************************
611 * Set bits for a positive character type *
612 *************************************************/
613
614 /* This function sets starting bits for a character type. In UTF-8 mode, we can
615 only do a direct setting for bytes less than 128, as otherwise there can be
616 confusion with bytes in the middle of UTF-8 characters. In a "traditional"
617 environment, the tables will only recognize ASCII characters anyway, but in at
618 least one Windows environment, some higher bytes bits were set in the tables.
619 So we deal with that case by considering the UTF-8 encoding.
620
621 Arguments:
622 start_bits the starting bitmap
623 cbit type the type of character wanted
624 table_limit 32 for non-UTF-8; 16 for UTF-8
625 cd the block with char table pointers
626
627 Returns: nothing
628 */
629
630 static void
631 set_type_bits(pcre_uint8 *start_bits, int cbit_type, int table_limit,
632 compile_data *cd)
633 {
634 register int c;
635 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
636 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
637 if (table_limit == 32) return;
638 for (c = 128; c < 256; c++)
639 {
640 if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
641 {
642 pcre_uchar buff[6];
643 (void)PRIV(ord2utf)(c, buff);
644 SET_BIT(buff[0]);
645 }
646 }
647 #endif
648 }
649
650
651 /*************************************************
652 * Set bits for a negative character type *
653 *************************************************/
654
655 /* This function sets starting bits for a negative character type such as \D.
656 In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
657 otherwise there can be confusion with bytes in the middle of UTF-8 characters.
658 Unlike in the positive case, where we can set appropriate starting bits for
659 specific high-valued UTF-8 characters, in this case we have to set the bits for
660 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
661 0xc0 (192) for simplicity.
662
663 Arguments:
664 start_bits the starting bitmap
665 cbit type the type of character wanted
666 table_limit 32 for non-UTF-8; 16 for UTF-8
667 cd the block with char table pointers
668
669 Returns: nothing
670 */
671
672 static void
673 set_nottype_bits(pcre_uint8 *start_bits, int cbit_type, int table_limit,
674 compile_data *cd)
675 {
676 register int c;
677 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
678 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
679 if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
680 #endif
681 }
682
683
684
685 /*************************************************
686 * Create bitmap of starting bytes *
687 *************************************************/
688
689 /* This function scans a compiled unanchored expression recursively and
690 attempts to build a bitmap of the set of possible starting bytes. As time goes
691 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
692 useful for parenthesized groups in patterns such as (a*)b where the group
693 provides some optional starting bytes but scanning must continue at the outer
694 level to find at least one mandatory byte. At the outermost level, this
695 function fails unless the result is SSB_DONE.
696
697 Arguments:
698 code points to an expression
699 start_bits points to a 32-byte table, initialized to 0
700 utf TRUE if in UTF-8 / UTF-16 mode
701 cd the block with char table pointers
702
703 Returns: SSB_FAIL => Failed to find any starting bytes
704 SSB_DONE => Found mandatory starting bytes
705 SSB_CONTINUE => Found optional starting bytes
706 SSB_UNKNOWN => Hit an unrecognized opcode
707 */
708
709 static int
710 set_start_bits(const pcre_uchar *code, pcre_uint8 *start_bits, BOOL utf,
711 compile_data *cd)
712 {
713 register int c;
714 int yield = SSB_DONE;
715 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
716 int table_limit = utf? 16:32;
717 #else
718 int table_limit = 32;
719 #endif
720
721 #if 0
722 /* ========================================================================= */
723 /* The following comment and code was inserted in January 1999. In May 2006,
724 when it was observed to cause compiler warnings about unused values, I took it
725 out again. If anybody is still using OS/2, they will have to put it back
726 manually. */
727
728 /* This next statement and the later reference to dummy are here in order to
729 trick the optimizer of the IBM C compiler for OS/2 into generating correct
730 code. Apparently IBM isn't going to fix the problem, and we would rather not
731 disable optimization (in this module it actually makes a big difference, and
732 the pcre module can use all the optimization it can get). */
733
734 volatile int dummy;
735 /* ========================================================================= */
736 #endif
737
738 do
739 {
740 BOOL try_next = TRUE;
741 const pcre_uchar *tcode = code + 1 + LINK_SIZE;
742
743 if (*code == OP_CBRA || *code == OP_SCBRA ||
744 *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += IMM2_SIZE;
745
746 while (try_next) /* Loop for items in this branch */
747 {
748 int rc;
749
750 switch(*tcode)
751 {
752 /* If we reach something we don't understand, it means a new opcode has
753 been created that hasn't been added to this code. Hopefully this problem
754 will be discovered during testing. */
755
756 default:
757 return SSB_UNKNOWN;
758
759 /* Fail for a valid opcode that implies no starting bits. */
760
761 case OP_ACCEPT:
762 case OP_ASSERT_ACCEPT:
763 case OP_ALLANY:
764 case OP_ANY:
765 case OP_ANYBYTE:
766 case OP_CIRC:
767 case OP_CIRCM:
768 case OP_CLOSE:
769 case OP_COMMIT:
770 case OP_COND:
771 case OP_CREF:
772 case OP_DEF:
773 case OP_DOLL:
774 case OP_DOLLM:
775 case OP_END:
776 case OP_EOD:
777 case OP_EODN:
778 case OP_EXTUNI:
779 case OP_FAIL:
780 case OP_MARK:
781 case OP_NCREF:
782 case OP_NOT:
783 case OP_NOTEXACT:
784 case OP_NOTEXACTI:
785 case OP_NOTI:
786 case OP_NOTMINPLUS:
787 case OP_NOTMINPLUSI:
788 case OP_NOTMINQUERY:
789 case OP_NOTMINQUERYI:
790 case OP_NOTMINSTAR:
791 case OP_NOTMINSTARI:
792 case OP_NOTMINUPTO:
793 case OP_NOTMINUPTOI:
794 case OP_NOTPLUS:
795 case OP_NOTPLUSI:
796 case OP_NOTPOSPLUS:
797 case OP_NOTPOSPLUSI:
798 case OP_NOTPOSQUERY:
799 case OP_NOTPOSQUERYI:
800 case OP_NOTPOSSTAR:
801 case OP_NOTPOSSTARI:
802 case OP_NOTPOSUPTO:
803 case OP_NOTPOSUPTOI:
804 case OP_NOTPROP:
805 case OP_NOTQUERY:
806 case OP_NOTQUERYI:
807 case OP_NOTSTAR:
808 case OP_NOTSTARI:
809 case OP_NOTUPTO:
810 case OP_NOTUPTOI:
811 case OP_NOT_HSPACE:
812 case OP_NOT_VSPACE:
813 case OP_NRREF:
814 case OP_PROP:
815 case OP_PRUNE:
816 case OP_PRUNE_ARG:
817 case OP_RECURSE:
818 case OP_REF:
819 case OP_REFI:
820 case OP_REVERSE:
821 case OP_RREF:
822 case OP_SCOND:
823 case OP_SET_SOM:
824 case OP_SKIP:
825 case OP_SKIP_ARG:
826 case OP_SOD:
827 case OP_SOM:
828 case OP_THEN:
829 case OP_THEN_ARG:
830 #if defined SUPPORT_UTF || !defined COMPILE_PCRE8
831 case OP_XCLASS:
832 #endif
833 return SSB_FAIL;
834
835 /* We can ignore word boundary tests. */
836
837 case OP_WORD_BOUNDARY:
838 case OP_NOT_WORD_BOUNDARY:
839 tcode++;
840 break;
841
842 /* If we hit a bracket or a positive lookahead assertion, recurse to set
843 bits from within the subpattern. If it can't find anything, we have to
844 give up. If it finds some mandatory character(s), we are done for this
845 branch. Otherwise, carry on scanning after the subpattern. */
846
847 case OP_BRA:
848 case OP_SBRA:
849 case OP_CBRA:
850 case OP_SCBRA:
851 case OP_BRAPOS:
852 case OP_SBRAPOS:
853 case OP_CBRAPOS:
854 case OP_SCBRAPOS:
855 case OP_ONCE:
856 case OP_ONCE_NC:
857 case OP_ASSERT:
858 rc = set_start_bits(tcode, start_bits, utf, cd);
859 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
860 if (rc == SSB_DONE) try_next = FALSE; else
861 {
862 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
863 tcode += 1 + LINK_SIZE;
864 }
865 break;
866
867 /* If we hit ALT or KET, it means we haven't found anything mandatory in
868 this branch, though we might have found something optional. For ALT, we
869 continue with the next alternative, but we have to arrange that the final
870 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
871 return SSB_CONTINUE: if this is the top level, that indicates failure,
872 but after a nested subpattern, it causes scanning to continue. */
873
874 case OP_ALT:
875 yield = SSB_CONTINUE;
876 try_next = FALSE;
877 break;
878
879 case OP_KET:
880 case OP_KETRMAX:
881 case OP_KETRMIN:
882 case OP_KETRPOS:
883 return SSB_CONTINUE;
884
885 /* Skip over callout */
886
887 case OP_CALLOUT:
888 tcode += 2 + 2*LINK_SIZE;
889 break;
890
891 /* Skip over lookbehind and negative lookahead assertions */
892
893 case OP_ASSERT_NOT:
894 case OP_ASSERTBACK:
895 case OP_ASSERTBACK_NOT:
896 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
897 tcode += 1 + LINK_SIZE;
898 break;
899
900 /* BRAZERO does the bracket, but carries on. */
901
902 case OP_BRAZERO:
903 case OP_BRAMINZERO:
904 case OP_BRAPOSZERO:
905 rc = set_start_bits(++tcode, start_bits, utf, cd);
906 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
907 /* =========================================================================
908 See the comment at the head of this function concerning the next line,
909 which was an old fudge for the benefit of OS/2.
910 dummy = 1;
911 ========================================================================= */
912 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
913 tcode += 1 + LINK_SIZE;
914 break;
915
916 /* SKIPZERO skips the bracket. */
917
918 case OP_SKIPZERO:
919 tcode++;
920 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
921 tcode += 1 + LINK_SIZE;
922 break;
923
924 /* Single-char * or ? sets the bit and tries the next item */
925
926 case OP_STAR:
927 case OP_MINSTAR:
928 case OP_POSSTAR:
929 case OP_QUERY:
930 case OP_MINQUERY:
931 case OP_POSQUERY:
932 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf);
933 break;
934
935 case OP_STARI:
936 case OP_MINSTARI:
937 case OP_POSSTARI:
938 case OP_QUERYI:
939 case OP_MINQUERYI:
940 case OP_POSQUERYI:
941 tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf);
942 break;
943
944 /* Single-char upto sets the bit and tries the next */
945
946 case OP_UPTO:
947 case OP_MINUPTO:
948 case OP_POSUPTO:
949 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, FALSE, cd, utf);
950 break;
951
952 case OP_UPTOI:
953 case OP_MINUPTOI:
954 case OP_POSUPTOI:
955 tcode = set_table_bit(start_bits, tcode + 1 + IMM2_SIZE, TRUE, cd, utf);
956 break;
957
958 /* At least one single char sets the bit and stops */
959
960 case OP_EXACT:
961 tcode += IMM2_SIZE;
962 /* Fall through */
963 case OP_CHAR:
964 case OP_PLUS:
965 case OP_MINPLUS:
966 case OP_POSPLUS:
967 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf);
968 try_next = FALSE;
969 break;
970
971 case OP_EXACTI:
972 tcode += IMM2_SIZE;
973 /* Fall through */
974 case OP_CHARI:
975 case OP_PLUSI:
976 case OP_MINPLUSI:
977 case OP_POSPLUSI:
978 (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf);
979 try_next = FALSE;
980 break;
981
982 /* Special spacing and line-terminating items. These recognize specific
983 lists of characters. The difference between VSPACE and ANYNL is that the
984 latter can match the two-character CRLF sequence, but that is not
985 relevant for finding the first character, so their code here is
986 identical. */
987
988 case OP_HSPACE:
989 SET_BIT(0x09);
990 SET_BIT(0x20);
991 #ifdef SUPPORT_UTF
992 if (utf)
993 {
994 #ifdef COMPILE_PCRE8
995 SET_BIT(0xC2); /* For U+00A0 */
996 SET_BIT(0xE1); /* For U+1680, U+180E */
997 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
998 SET_BIT(0xE3); /* For U+3000 */
999 #endif
1000 #ifdef COMPILE_PCRE16
1001 SET_BIT(0xA0);
1002 SET_BIT(0xFF); /* For characters > 255 */
1003 #endif
1004 }
1005 else
1006 #endif /* SUPPORT_UTF */
1007 SET_BIT(0xA0);
1008 try_next = FALSE;
1009 break;
1010
1011 case OP_ANYNL:
1012 case OP_VSPACE:
1013 SET_BIT(0x0A);
1014 SET_BIT(0x0B);
1015 SET_BIT(0x0C);
1016 SET_BIT(0x0D);
1017 #ifdef SUPPORT_UTF
1018 if (utf)
1019 {
1020 #ifdef COMPILE_PCRE8
1021 SET_BIT(0xC2); /* For U+0085 */
1022 SET_BIT(0xE2); /* For U+2028, U+2029 */
1023 #endif
1024 #ifdef COMPILE_PCRE16
1025 SET_BIT(0x85);
1026 SET_BIT(0xFF); /* For characters > 255 */
1027 #endif
1028 }
1029 else
1030 #endif /* SUPPORT_UTF */
1031 SET_BIT(0x85);
1032 try_next = FALSE;
1033 break;
1034
1035 /* Single character types set the bits and stop. Note that if PCRE_UCP
1036 is set, we do not see these op codes because \d etc are converted to
1037 properties. Therefore, these apply in the case when only characters less
1038 than 256 are recognized to match the types. */
1039
1040 case OP_NOT_DIGIT:
1041 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1042 try_next = FALSE;
1043 break;
1044
1045 case OP_DIGIT:
1046 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1047 try_next = FALSE;
1048 break;
1049
1050 /* The cbit_space table has vertical tab as whitespace; we have to
1051 ensure it is set as not whitespace. */
1052
1053 case OP_NOT_WHITESPACE:
1054 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1055 start_bits[1] |= 0x08;
1056 try_next = FALSE;
1057 break;
1058
1059 /* The cbit_space table has vertical tab as whitespace; we have to
1060 not set it from the table. */
1061
1062 case OP_WHITESPACE:
1063 c = start_bits[1]; /* Save in case it was already set */
1064 set_type_bits(start_bits, cbit_space, table_limit, cd);
1065 start_bits[1] = (start_bits[1] & ~0x08) | c;
1066 try_next = FALSE;
1067 break;
1068
1069 case OP_NOT_WORDCHAR:
1070 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1071 try_next = FALSE;
1072 break;
1073
1074 case OP_WORDCHAR:
1075 set_type_bits(start_bits, cbit_word, table_limit, cd);
1076 try_next = FALSE;
1077 break;
1078
1079 /* One or more character type fudges the pointer and restarts, knowing
1080 it will hit a single character type and stop there. */
1081
1082 case OP_TYPEPLUS:
1083 case OP_TYPEMINPLUS:
1084 case OP_TYPEPOSPLUS:
1085 tcode++;
1086 break;
1087
1088 case OP_TYPEEXACT:
1089 tcode += 1 + IMM2_SIZE;
1090 break;
1091
1092 /* Zero or more repeats of character types set the bits and then
1093 try again. */
1094
1095 case OP_TYPEUPTO:
1096 case OP_TYPEMINUPTO:
1097 case OP_TYPEPOSUPTO:
1098 tcode += IMM2_SIZE; /* Fall through */
1099
1100 case OP_TYPESTAR:
1101 case OP_TYPEMINSTAR:
1102 case OP_TYPEPOSSTAR:
1103 case OP_TYPEQUERY:
1104 case OP_TYPEMINQUERY:
1105 case OP_TYPEPOSQUERY:
1106 switch(tcode[1])
1107 {
1108 default:
1109 case OP_ANY:
1110 case OP_ALLANY:
1111 return SSB_FAIL;
1112
1113 case OP_HSPACE:
1114 SET_BIT(0x09);
1115 SET_BIT(0x20);
1116 #ifdef COMPILE_PCRE8
1117 if (utf)
1118 {
1119 #ifdef COMPILE_PCRE8
1120 SET_BIT(0xC2); /* For U+00A0 */
1121 SET_BIT(0xE1); /* For U+1680, U+180E */
1122 SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1123 SET_BIT(0xE3); /* For U+3000 */
1124 #endif
1125 #ifdef COMPILE_PCRE16
1126 SET_BIT(0xA0);
1127 SET_BIT(0xFF); /* For characters > 255 */
1128 #endif
1129 }
1130 else
1131 #endif /* SUPPORT_UTF */
1132 SET_BIT(0xA0);
1133 break;
1134
1135 case OP_ANYNL:
1136 case OP_VSPACE:
1137 SET_BIT(0x0A);
1138 SET_BIT(0x0B);
1139 SET_BIT(0x0C);
1140 SET_BIT(0x0D);
1141 #ifdef COMPILE_PCRE8
1142 if (utf)
1143 {
1144 #ifdef COMPILE_PCRE8
1145 SET_BIT(0xC2); /* For U+0085 */
1146 SET_BIT(0xE2); /* For U+2028, U+2029 */
1147 #endif
1148 #ifdef COMPILE_PCRE16
1149 SET_BIT(0x85);
1150 SET_BIT(0xFF); /* For characters > 255 */
1151 #endif
1152 }
1153 else
1154 #endif /* SUPPORT_UTF */
1155 SET_BIT(0x85);
1156 break;
1157
1158 case OP_NOT_DIGIT:
1159 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1160 break;
1161
1162 case OP_DIGIT:
1163 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1164 break;
1165
1166 /* The cbit_space table has vertical tab as whitespace; we have to
1167 ensure it gets set as not whitespace. */
1168
1169 case OP_NOT_WHITESPACE:
1170 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1171 start_bits[1] |= 0x08;
1172 break;
1173
1174 /* The cbit_space table has vertical tab as whitespace; we have to
1175 avoid setting it. */
1176
1177 case OP_WHITESPACE:
1178 c = start_bits[1]; /* Save in case it was already set */
1179 set_type_bits(start_bits, cbit_space, table_limit, cd);
1180 start_bits[1] = (start_bits[1] & ~0x08) | c;
1181 break;
1182
1183 case OP_NOT_WORDCHAR:
1184 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1185 break;
1186
1187 case OP_WORDCHAR:
1188 set_type_bits(start_bits, cbit_word, table_limit, cd);
1189 break;
1190 }
1191
1192 tcode += 2;
1193 break;
1194
1195 /* Character class where all the information is in a bit map: set the
1196 bits and either carry on or not, according to the repeat count. If it was
1197 a negative class, and we are operating with UTF-8 characters, any byte
1198 with a value >= 0xc4 is a potentially valid starter because it starts a
1199 character with a value > 255. */
1200
1201 case OP_NCLASS:
1202 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
1203 if (utf)
1204 {
1205 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1206 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1207 }
1208 #endif
1209 #ifdef COMPILE_PCRE16
1210 SET_BIT(0xFF); /* For characters > 255 */
1211 #endif
1212 /* Fall through */
1213
1214 case OP_CLASS:
1215 {
1216 pcre_uint8 *map;
1217 tcode++;
1218 map = (pcre_uint8 *)tcode;
1219
1220 /* In UTF-8 mode, the bits in a bit map correspond to character
1221 values, not to byte values. However, the bit map we are constructing is
1222 for byte values. So we have to do a conversion for characters whose
1223 value is > 127. In fact, there are only two possible starting bytes for
1224 characters in the range 128 - 255. */
1225
1226 #if defined SUPPORT_UTF && defined COMPILE_PCRE8
1227 if (utf)
1228 {
1229 for (c = 0; c < 16; c++) start_bits[c] |= map[c];
1230 for (c = 128; c < 256; c++)
1231 {
1232 if ((map[c/8] && (1 << (c&7))) != 0)
1233 {
1234 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1235 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1236 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1237 }
1238 }
1239 }
1240 else
1241 #endif
1242 {
1243 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1244 for (c = 0; c < 32; c++) start_bits[c] |= map[c];
1245 }
1246
1247 /* Advance past the bit map, and act on what follows. For a zero
1248 minimum repeat, continue; otherwise stop processing. */
1249
1250 tcode += 32 / sizeof(pcre_uchar);
1251 switch (*tcode)
1252 {
1253 case OP_CRSTAR:
1254 case OP_CRMINSTAR:
1255 case OP_CRQUERY:
1256 case OP_CRMINQUERY:
1257 tcode++;
1258 break;
1259
1260 case OP_CRRANGE:
1261 case OP_CRMINRANGE:
1262 if (GET2(tcode, 1) == 0) tcode += 1 + 2 * IMM2_SIZE;
1263 else try_next = FALSE;
1264 break;
1265
1266 default:
1267 try_next = FALSE;
1268 break;
1269 }
1270 }
1271 break; /* End of bitmap class handling */
1272
1273 } /* End of switch */
1274 } /* End of try_next loop */
1275
1276 code += GET(code, 1); /* Advance to next branch */
1277 }
1278 while (*code == OP_ALT);
1279 return yield;
1280 }
1281
1282
1283
1284
1285
1286 /*************************************************
1287 * Study a compiled expression *
1288 *************************************************/
1289
1290 /* This function is handed a compiled expression that it must study to produce
1291 information that will speed up the matching. It returns a pcre_extra block
1292 which then gets handed back to pcre_exec().
1293
1294 Arguments:
1295 re points to the compiled expression
1296 options contains option bits
1297 errorptr points to where to place error messages;
1298 set NULL unless error
1299
1300 Returns: pointer to a pcre_extra block, with study_data filled in and the
1301 appropriate flags set;
1302 NULL on error or if no optimization possible
1303 */
1304
1305 #ifdef COMPILE_PCRE8
1306 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1307 pcre_study(const pcre *external_re, int options, const char **errorptr)
1308 #else
1309 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1310 pcre16_study(const pcre *external_re, int options, const char **errorptr)
1311 #endif
1312 {
1313 int min;
1314 BOOL bits_set = FALSE;
1315 pcre_uint8 start_bits[32];
1316 pcre_extra *extra = NULL;
1317 pcre_study_data *study;
1318 const pcre_uint8 *tables;
1319 pcre_uchar *code;
1320 compile_data compile_block;
1321 const real_pcre *re = (const real_pcre *)external_re;
1322
1323 *errorptr = NULL;
1324
1325 if (re == NULL || re->magic_number != MAGIC_NUMBER)
1326 {
1327 *errorptr = "argument is not a compiled regular expression";
1328 return NULL;
1329 }
1330
1331 if ((re->flags & PCRE_MODE) == 0)
1332 {
1333 #ifdef COMPILE_PCRE8
1334 *errorptr = "argument is compiled in 16 bit mode";
1335 #else
1336 *errorptr = "argument is compiled in 8 bit mode";
1337 #endif
1338 return NULL;
1339 }
1340
1341 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1342 {
1343 *errorptr = "unknown or incorrect option bit(s) set";
1344 return NULL;
1345 }
1346
1347 code = (pcre_uchar *)re + re->name_table_offset +
1348 (re->name_count * re->name_entry_size);
1349
1350 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1351 a multiline pattern that matches only at "line starts", there is no point in
1352 seeking a list of starting bytes. */
1353
1354 if ((re->options & PCRE_ANCHORED) == 0 &&
1355 (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1356 {
1357 int rc;
1358
1359 /* Set the character tables in the block that is passed around */
1360
1361 tables = re->tables;
1362
1363 #ifdef COMPILE_PCRE8
1364 if (tables == NULL)
1365 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1366 (void *)(&tables));
1367 #else
1368 if (tables == NULL)
1369 (void)pcre16_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1370 (void *)(&tables));
1371 #endif
1372
1373 compile_block.lcc = tables + lcc_offset;
1374 compile_block.fcc = tables + fcc_offset;
1375 compile_block.cbits = tables + cbits_offset;
1376 compile_block.ctypes = tables + ctypes_offset;
1377
1378 /* See if we can find a fixed set of initial characters for the pattern. */
1379
1380 memset(start_bits, 0, 32 * sizeof(pcre_uint8));
1381 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1382 &compile_block);
1383 bits_set = rc == SSB_DONE;
1384 if (rc == SSB_UNKNOWN)
1385 {
1386 *errorptr = "internal error: opcode not recognized";
1387 return NULL;
1388 }
1389 }
1390
1391 /* Find the minimum length of subject string. */
1392
1393 switch(min = find_minlength(code, code, re->options, 0))
1394 {
1395 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1396 case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1397 default: break;
1398 }
1399
1400 /* If a set of starting bytes has been identified, or if the minimum length is
1401 greater than zero, or if JIT optimization has been requested, get a pcre_extra
1402 block and a pcre_study_data block. The study data is put in the latter, which
1403 is pointed to by the former, which may also get additional data set later by
1404 the calling program. At the moment, the size of pcre_study_data is fixed. We
1405 nevertheless save it in a field for returning via the pcre_fullinfo() function
1406 so that if it becomes variable in the future, we don't have to change that
1407 code. */
1408
1409 if (bits_set || min > 0
1410 #ifdef SUPPORT_JIT
1411 || (options & PCRE_STUDY_JIT_COMPILE) != 0
1412 #endif
1413 )
1414 {
1415 extra = (pcre_extra *)(PUBL(malloc))
1416 (sizeof(pcre_extra) + sizeof(pcre_study_data));
1417 if (extra == NULL)
1418 {
1419 *errorptr = "failed to get memory";
1420 return NULL;
1421 }
1422
1423 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1424 extra->flags = PCRE_EXTRA_STUDY_DATA;
1425 extra->study_data = study;
1426
1427 study->size = sizeof(pcre_study_data);
1428 study->flags = 0;
1429
1430 /* Set the start bits always, to avoid unset memory errors if the
1431 study data is written to a file, but set the flag only if any of the bits
1432 are set, to save time looking when none are. */
1433
1434 if (bits_set)
1435 {
1436 study->flags |= PCRE_STUDY_MAPPED;
1437 memcpy(study->start_bits, start_bits, sizeof(start_bits));
1438 }
1439 else memset(study->start_bits, 0, 32 * sizeof(pcre_uint8));
1440
1441 #ifdef PCRE_DEBUG
1442 if (bits_set)
1443 {
1444 pcre_uint8 *ptr = (pcre_uint32 *)start_bits;
1445 int i;
1446
1447 printf("Start bits:\n");
1448 for (i = 0; i < 32; i++)
1449 printf("%3d: %02x%s", i * 8, *ptr++, ((i + 1) & 0x7) != 0? " " : "\n");
1450 }
1451 #endif
1452
1453 /* Always set the minlength value in the block, because the JIT compiler
1454 makes use of it. However, don't set the bit unless the length is greater than
1455 zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1456 checking the zero case. */
1457
1458 if (min > 0)
1459 {
1460 study->flags |= PCRE_STUDY_MINLEN;
1461 study->minlength = min;
1462 }
1463 else study->minlength = 0;
1464
1465 /* If JIT support was compiled and requested, attempt the JIT compilation.
1466 If no starting bytes were found, and the minimum length is zero, and JIT
1467 compilation fails, abandon the extra block and return NULL. */
1468
1469 #ifdef SUPPORT_JIT
1470 extra->executable_jit = NULL;
1471 if ((options & PCRE_STUDY_JIT_COMPILE) != 0) PRIV(jit_compile)(re, extra);
1472 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0)
1473 {
1474 pcre_free_study(extra);
1475 extra = NULL;
1476 }
1477 #endif
1478 }
1479
1480 return extra;
1481 }
1482
1483
1484 /*************************************************
1485 * Free the study data *
1486 *************************************************/
1487
1488 /* This function frees the memory that was obtained by pcre_study().
1489
1490 Argument: a pointer to the pcre_extra block
1491 Returns: nothing
1492 */
1493
1494 #ifdef COMPILE_PCRE8
1495 PCRE_EXP_DEFN void
1496 pcre_free_study(pcre_extra *extra)
1497 #else
1498 PCRE_EXP_DEFN void
1499 pcre16_free_study(pcre_extra *extra)
1500 #endif
1501 {
1502 #ifdef SUPPORT_JIT
1503 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1504 extra->executable_jit != NULL)
1505 PRIV(jit_free)(extra->executable_jit);
1506 #endif
1507 PUBL(free)(extra);
1508 }
1509
1510 /* End of pcre_study.c */

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