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

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Revision 729 - (hide annotations) (download)
Mon Oct 10 16:02:20 2011 UTC (3 years, 2 months ago) by ph10
Original Path: code/trunk/pcre_study.c
File MIME type: text/plain
File size: 38862 byte(s)
Fix THEN:ARG bug introduced with *THEN refactoring.

1 nigel 77 /*************************************************
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 ph10 475 Copyright (c) 1997-2010 University of Cambridge
10 nigel 77
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 ph10 200 #ifdef HAVE_CONFIG_H
46 ph10 236 #include "config.h"
47 ph10 200 #endif
48 ph10 199
49 nigel 77 #include "pcre_internal.h"
50    
51 ph10 524 #define SET_BIT(c) start_bits[c/8] |= (1 << (c&7))
52 nigel 77
53 nigel 93 /* Returns from set_start_bits() */
54    
55 ph10 605 enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE, SSB_UNKNOWN };
56 nigel 93
57    
58 ph10 455
59 nigel 77 /*************************************************
60 ph10 455 * Find the minimum subject length for a group *
61     *************************************************/
62    
63     /* Scan a parenthesized group and compute the minimum length of subject that
64 ph10 461 is needed to match it. This is a lower bound; it does not mean there is a
65 ph10 455 string of that length that matches. In UTF8 mode, the result is in characters
66     rather than bytes.
67    
68     Arguments:
69 ph10 697 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 ph10 455
74     Returns: the minimum length
75 ph10 697 -1 if \C in UTF-8 mode or (*ACCEPT) was encountered
76 ph10 461 -2 internal error (missing capturing bracket)
77 ph10 605 -3 internal error (opcode not listed)
78 ph10 455 */
79    
80     static int
81 ph10 612 find_minlength(const uschar *code, const uschar *startcode, int options,
82 ph10 697 int recurse_depth)
83 ph10 455 {
84     int length = -1;
85     BOOL utf8 = (options & PCRE_UTF8) != 0;
86     BOOL had_recurse = FALSE;
87     register int branchlength = 0;
88     register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
89    
90 ph10 604 if (*code == OP_CBRA || *code == OP_SCBRA ||
91     *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += 2;
92 ph10 455
93     /* Scan along the opcodes for this branch. If we get to the end of the
94     branch, check the length against that of the other branches. */
95    
96     for (;;)
97     {
98     int d, min;
99 ph10 461 uschar *cs, *ce;
100 ph10 455 register int op = *cc;
101 ph10 461
102 ph10 455 switch (op)
103     {
104 ph10 471 case OP_COND:
105     case OP_SCOND:
106    
107     /* If there is only one branch in a condition, the implied branch has zero
108     length, so we don't add anything. This covers the DEFINE "condition"
109     automatically. */
110    
111     cs = cc + GET(cc, 1);
112     if (*cs != OP_ALT)
113     {
114     cc = cs + 1 + LINK_SIZE;
115     break;
116     }
117    
118     /* Otherwise we can fall through and treat it the same as any other
119     subpattern. */
120    
121 ph10 455 case OP_CBRA:
122 ph10 461 case OP_SCBRA:
123 ph10 455 case OP_BRA:
124 ph10 461 case OP_SBRA:
125 ph10 604 case OP_CBRAPOS:
126     case OP_SCBRAPOS:
127     case OP_BRAPOS:
128     case OP_SBRAPOS:
129 ph10 455 case OP_ONCE:
130 ph10 723 case OP_ONCE_NC:
131 ph10 697 d = find_minlength(cc, startcode, options, recurse_depth);
132 ph10 455 if (d < 0) return d;
133     branchlength += d;
134     do cc += GET(cc, 1); while (*cc == OP_ALT);
135     cc += 1 + LINK_SIZE;
136     break;
137    
138 ph10 697 /* ACCEPT makes things far too complicated; we have to give up. */
139 ph10 455
140 ph10 654 case OP_ACCEPT:
141     case OP_ASSERT_ACCEPT:
142 ph10 708 return -1;
143 ph10 697
144     /* Reached end of a branch; if it's a ket it is the end of a nested
145     call. If it's ALT it is an alternation in a nested call. If it is END it's
146 ph10 708 the end of the outer call. All can be handled by the same code. If an
147     ACCEPT was previously encountered, use the length that was in force at that
148 ph10 697 time, and pass back the shortest ACCEPT length. */
149 ph10 708
150 ph10 455 case OP_ALT:
151     case OP_KET:
152     case OP_KETRMAX:
153     case OP_KETRMIN:
154 ph10 605 case OP_KETRPOS:
155 ph10 455 case OP_END:
156 ph10 461 if (length < 0 || (!had_recurse && branchlength < length))
157 ph10 455 length = branchlength;
158 ph10 612 if (op != OP_ALT) return length;
159 ph10 455 cc += 1 + LINK_SIZE;
160     branchlength = 0;
161 ph10 461 had_recurse = FALSE;
162 ph10 455 break;
163    
164     /* Skip over assertive subpatterns */
165    
166     case OP_ASSERT:
167     case OP_ASSERT_NOT:
168     case OP_ASSERTBACK:
169     case OP_ASSERTBACK_NOT:
170     do cc += GET(cc, 1); while (*cc == OP_ALT);
171     /* Fall through */
172    
173     /* Skip over things that don't match chars */
174    
175     case OP_REVERSE:
176     case OP_CREF:
177 ph10 459 case OP_NCREF:
178 ph10 455 case OP_RREF:
179 ph10 459 case OP_NRREF:
180 ph10 455 case OP_DEF:
181     case OP_CALLOUT:
182     case OP_SOD:
183     case OP_SOM:
184     case OP_EOD:
185     case OP_EODN:
186     case OP_CIRC:
187 ph10 602 case OP_CIRCM:
188 ph10 455 case OP_DOLL:
189 ph10 602 case OP_DOLLM:
190 ph10 455 case OP_NOT_WORD_BOUNDARY:
191     case OP_WORD_BOUNDARY:
192     cc += _pcre_OP_lengths[*cc];
193     break;
194 ph10 461
195 ph10 455 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
196    
197     case OP_BRAZERO:
198 ph10 461 case OP_BRAMINZERO:
199 ph10 604 case OP_BRAPOSZERO:
200 ph10 455 case OP_SKIPZERO:
201     cc += _pcre_OP_lengths[*cc];
202     do cc += GET(cc, 1); while (*cc == OP_ALT);
203     cc += 1 + LINK_SIZE;
204     break;
205    
206     /* Handle literal characters and + repetitions */
207    
208     case OP_CHAR:
209 ph10 602 case OP_CHARI:
210 ph10 455 case OP_NOT:
211 ph10 602 case OP_NOTI:
212 ph10 455 case OP_PLUS:
213 ph10 603 case OP_PLUSI:
214 ph10 455 case OP_MINPLUS:
215 ph10 603 case OP_MINPLUSI:
216 ph10 455 case OP_POSPLUS:
217 ph10 603 case OP_POSPLUSI:
218 ph10 455 case OP_NOTPLUS:
219 ph10 603 case OP_NOTPLUSI:
220 ph10 455 case OP_NOTMINPLUS:
221 ph10 603 case OP_NOTMINPLUSI:
222 ph10 455 case OP_NOTPOSPLUS:
223 ph10 603 case OP_NOTPOSPLUSI:
224 ph10 455 branchlength++;
225     cc += 2;
226     #ifdef SUPPORT_UTF8
227     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
228     #endif
229     break;
230 ph10 461
231 ph10 455 case OP_TYPEPLUS:
232     case OP_TYPEMINPLUS:
233 ph10 461 case OP_TYPEPOSPLUS:
234 ph10 455 branchlength++;
235     cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
236     break;
237    
238     /* Handle exact repetitions. The count is already in characters, but we
239     need to skip over a multibyte character in UTF8 mode. */
240    
241     case OP_EXACT:
242 ph10 603 case OP_EXACTI:
243 ph10 461 case OP_NOTEXACT:
244 ph10 603 case OP_NOTEXACTI:
245 ph10 455 branchlength += GET2(cc,1);
246     cc += 4;
247     #ifdef SUPPORT_UTF8
248     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
249     #endif
250     break;
251    
252     case OP_TYPEEXACT:
253     branchlength += GET2(cc,1);
254     cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
255     break;
256    
257     /* Handle single-char non-literal matchers */
258    
259     case OP_PROP:
260     case OP_NOTPROP:
261     cc += 2;
262     /* Fall through */
263    
264     case OP_NOT_DIGIT:
265     case OP_DIGIT:
266     case OP_NOT_WHITESPACE:
267     case OP_WHITESPACE:
268     case OP_NOT_WORDCHAR:
269     case OP_WORDCHAR:
270     case OP_ANY:
271     case OP_ALLANY:
272     case OP_EXTUNI:
273 ph10 461 case OP_HSPACE:
274 ph10 455 case OP_NOT_HSPACE:
275     case OP_VSPACE:
276 ph10 461 case OP_NOT_VSPACE:
277 ph10 455 branchlength++;
278     cc++;
279     break;
280 ph10 461
281 ph10 654 /* "Any newline" might match two characters, but it also might match just
282 ph10 611 one. */
283 ph10 461
284 ph10 455 case OP_ANYNL:
285 ph10 611 branchlength += 1;
286 ph10 455 cc++;
287 ph10 461 break;
288 ph10 455
289     /* The single-byte matcher means we can't proceed in UTF-8 mode */
290    
291     case OP_ANYBYTE:
292     #ifdef SUPPORT_UTF8
293     if (utf8) return -1;
294     #endif
295     branchlength++;
296     cc++;
297 ph10 461 break;
298 ph10 455
299     /* For repeated character types, we have to test for \p and \P, which have
300     an extra two bytes of parameters. */
301    
302     case OP_TYPESTAR:
303     case OP_TYPEMINSTAR:
304     case OP_TYPEQUERY:
305     case OP_TYPEMINQUERY:
306     case OP_TYPEPOSSTAR:
307     case OP_TYPEPOSQUERY:
308     if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
309     cc += _pcre_OP_lengths[op];
310     break;
311    
312     case OP_TYPEUPTO:
313     case OP_TYPEMINUPTO:
314     case OP_TYPEPOSUPTO:
315     if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
316     cc += _pcre_OP_lengths[op];
317     break;
318    
319     /* Check a class for variable quantification */
320    
321     #ifdef SUPPORT_UTF8
322     case OP_XCLASS:
323     cc += GET(cc, 1) - 33;
324     /* Fall through */
325     #endif
326    
327     case OP_CLASS:
328     case OP_NCLASS:
329     cc += 33;
330    
331     switch (*cc)
332     {
333     case OP_CRPLUS:
334     case OP_CRMINPLUS:
335     branchlength++;
336 ph10 461 /* Fall through */
337 ph10 455
338     case OP_CRSTAR:
339     case OP_CRMINSTAR:
340     case OP_CRQUERY:
341     case OP_CRMINQUERY:
342 ph10 461 cc++;
343 ph10 455 break;
344 ph10 461
345 ph10 455 case OP_CRRANGE:
346     case OP_CRMINRANGE:
347     branchlength += GET2(cc,1);
348     cc += 5;
349     break;
350 ph10 461
351 ph10 455 default:
352     branchlength++;
353 ph10 461 break;
354 ph10 455 }
355     break;
356 ph10 461
357     /* Backreferences and subroutine calls are treated in the same way: we find
358     the minimum length for the subpattern. A recursion, however, causes an
359 ph10 455 a flag to be set that causes the length of this branch to be ignored. The
360     logic is that a recursion can only make sense if there is another
361     alternation that stops the recursing. That will provide the minimum length
362     (when no recursion happens). A backreference within the group that it is
363 ph10 469 referencing behaves in the same way.
364    
365 ph10 467 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
366     matches an empty string (by default it causes a matching failure), so in
367     that case we must set the minimum length to zero. */
368 ph10 461
369 ph10 455 case OP_REF:
370 ph10 602 case OP_REFI:
371 ph10 467 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
372 ph10 469 {
373 ph10 467 ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
374     if (cs == NULL) return -2;
375     do ce += GET(ce, 1); while (*ce == OP_ALT);
376     if (cc > cs && cc < ce)
377     {
378     d = 0;
379     had_recurse = TRUE;
380     }
381 ph10 654 else
382 ph10 612 {
383 ph10 697 d = find_minlength(cs, startcode, options, recurse_depth);
384 ph10 654 }
385 ph10 461 }
386 ph10 469 else d = 0;
387 ph10 461 cc += 3;
388 ph10 455
389     /* Handle repeated back references */
390 ph10 461
391 ph10 455 switch (*cc)
392     {
393     case OP_CRSTAR:
394     case OP_CRMINSTAR:
395     case OP_CRQUERY:
396     case OP_CRMINQUERY:
397     min = 0;
398     cc++;
399     break;
400 ph10 605
401     case OP_CRPLUS:
402     case OP_CRMINPLUS:
403     min = 1;
404     cc++;
405     break;
406    
407 ph10 455 case OP_CRRANGE:
408     case OP_CRMINRANGE:
409     min = GET2(cc, 1);
410     cc += 5;
411     break;
412 ph10 461
413 ph10 455 default:
414     min = 1;
415     break;
416     }
417    
418     branchlength += min * d;
419 ph10 461 break;
420 ph10 455
421 ph10 654 /* We can easily detect direct recursion, but not mutual recursion. This is
422     caught by a recursion depth count. */
423    
424 ph10 461 case OP_RECURSE:
425 ph10 455 cs = ce = (uschar *)startcode + GET(cc, 1);
426     if (cs == NULL) return -2;
427     do ce += GET(ce, 1); while (*ce == OP_ALT);
428 ph10 620 if ((cc > cs && cc < ce) || recurse_depth > 10)
429 ph10 461 had_recurse = TRUE;
430     else
431 ph10 654 {
432 ph10 697 branchlength += find_minlength(cs, startcode, options, recurse_depth + 1);
433 ph10 654 }
434 ph10 455 cc += 1 + LINK_SIZE;
435     break;
436    
437     /* Anything else does not or need not match a character. We can get the
438 ph10 461 item's length from the table, but for those that can match zero occurrences
439 ph10 602 of a character, we must take special action for UTF-8 characters. As it
440     happens, the "NOT" versions of these opcodes are used at present only for
441     ASCII characters, so they could be omitted from this list. However, in
442 ph10 605 future that may change, so we include them here so as not to leave a
443 ph10 603 gotcha for a future maintainer. */
444 ph10 461
445 ph10 455 case OP_UPTO:
446 ph10 602 case OP_UPTOI:
447 ph10 461 case OP_NOTUPTO:
448 ph10 602 case OP_NOTUPTOI:
449 ph10 455 case OP_MINUPTO:
450 ph10 602 case OP_MINUPTOI:
451 ph10 461 case OP_NOTMINUPTO:
452 ph10 602 case OP_NOTMINUPTOI:
453 ph10 455 case OP_POSUPTO:
454 ph10 602 case OP_POSUPTOI:
455     case OP_NOTPOSUPTO:
456     case OP_NOTPOSUPTOI:
457    
458 ph10 455 case OP_STAR:
459 ph10 602 case OP_STARI:
460     case OP_NOTSTAR:
461     case OP_NOTSTARI:
462 ph10 455 case OP_MINSTAR:
463 ph10 602 case OP_MINSTARI:
464 ph10 461 case OP_NOTMINSTAR:
465 ph10 602 case OP_NOTMINSTARI:
466 ph10 455 case OP_POSSTAR:
467 ph10 602 case OP_POSSTARI:
468 ph10 461 case OP_NOTPOSSTAR:
469 ph10 602 case OP_NOTPOSSTARI:
470    
471 ph10 455 case OP_QUERY:
472 ph10 602 case OP_QUERYI:
473     case OP_NOTQUERY:
474     case OP_NOTQUERYI:
475 ph10 455 case OP_MINQUERY:
476 ph10 602 case OP_MINQUERYI:
477 ph10 455 case OP_NOTMINQUERY:
478 ph10 602 case OP_NOTMINQUERYI:
479 ph10 455 case OP_POSQUERY:
480 ph10 602 case OP_POSQUERYI:
481 ph10 461 case OP_NOTPOSQUERY:
482 ph10 602 case OP_NOTPOSQUERYI:
483    
484 ph10 455 cc += _pcre_OP_lengths[op];
485 ph10 461 #ifdef SUPPORT_UTF8
486 ph10 455 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
487 ph10 461 #endif
488 ph10 455 break;
489 ph10 512
490 ph10 510 /* Skip these, but we need to add in the name length. */
491 ph10 512
492 ph10 510 case OP_MARK:
493     case OP_PRUNE_ARG:
494     case OP_SKIP_ARG:
495 ph10 729 case OP_THEN_ARG:
496 ph10 510 cc += _pcre_OP_lengths[op] + cc[1];
497 ph10 512 break;
498 ph10 455
499 ph10 603 /* The remaining opcodes are just skipped over. */
500 ph10 461
501 ph10 603 case OP_CLOSE:
502     case OP_COMMIT:
503     case OP_FAIL:
504     case OP_PRUNE:
505     case OP_SET_SOM:
506     case OP_SKIP:
507 ph10 605 case OP_THEN:
508 ph10 455 cc += _pcre_OP_lengths[op];
509     break;
510 ph10 605
511 ph10 603 /* This should not occur: we list all opcodes explicitly so that when
512     new ones get added they are properly considered. */
513    
514     default:
515     return -3;
516 ph10 455 }
517     }
518     /* Control never gets here */
519     }
520    
521    
522    
523     /*************************************************
524 nigel 77 * Set a bit and maybe its alternate case *
525     *************************************************/
526    
527 ph10 535 /* Given a character, set its first byte's bit in the table, and also the
528 ph10 520 corresponding bit for the other version of a letter if we are caseless. In
529     UTF-8 mode, for characters greater than 127, we can only do the caseless thing
530     when Unicode property support is available.
531 nigel 77
532     Arguments:
533     start_bits points to the bit map
534 ph10 520 p points to the character
535 nigel 77 caseless the caseless flag
536     cd the block with char table pointers
537 ph10 535 utf8 TRUE for UTF-8 mode
538 nigel 77
539 ph10 520 Returns: pointer after the character
540 nigel 77 */
541    
542 ph10 520 static const uschar *
543     set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
544     compile_data *cd, BOOL utf8)
545 nigel 77 {
546 ph10 520 unsigned int c = *p;
547    
548 ph10 524 SET_BIT(c);
549    
550 ph10 520 #ifdef SUPPORT_UTF8
551     if (utf8 && c > 127)
552     {
553     GETCHARINC(c, p);
554     #ifdef SUPPORT_UCP
555     if (caseless)
556     {
557 ph10 535 uschar buff[8];
558 ph10 520 c = UCD_OTHERCASE(c);
559 ph10 535 (void)_pcre_ord2utf8(c, buff);
560     SET_BIT(buff[0]);
561     }
562     #endif
563 ph10 520 return p;
564     }
565 ph10 535 #endif
566 ph10 520
567     /* Not UTF-8 mode, or character is less than 127. */
568    
569 ph10 524 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
570 ph10 520 return p + 1;
571 nigel 77 }
572    
573    
574    
575     /*************************************************
576 ph10 539 * Set bits for a positive character type *
577     *************************************************/
578    
579     /* This function sets starting bits for a character type. In UTF-8 mode, we can
580     only do a direct setting for bytes less than 128, as otherwise there can be
581     confusion with bytes in the middle of UTF-8 characters. In a "traditional"
582     environment, the tables will only recognize ASCII characters anyway, but in at
583     least one Windows environment, some higher bytes bits were set in the tables.
584     So we deal with that case by considering the UTF-8 encoding.
585    
586     Arguments:
587     start_bits the starting bitmap
588     cbit type the type of character wanted
589     table_limit 32 for non-UTF-8; 16 for UTF-8
590 ph10 545 cd the block with char table pointers
591 ph10 539
592     Returns: nothing
593     */
594    
595     static void
596     set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
597     compile_data *cd)
598     {
599 ph10 545 register int c;
600 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
601     if (table_limit == 32) return;
602     for (c = 128; c < 256; c++)
603     {
604     if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
605     {
606     uschar buff[8];
607     (void)_pcre_ord2utf8(c, buff);
608 ph10 545 SET_BIT(buff[0]);
609     }
610     }
611 ph10 539 }
612    
613    
614     /*************************************************
615     * Set bits for a negative character type *
616     *************************************************/
617    
618     /* This function sets starting bits for a negative character type such as \D.
619     In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
620     otherwise there can be confusion with bytes in the middle of UTF-8 characters.
621 ph10 545 Unlike in the positive case, where we can set appropriate starting bits for
622 ph10 539 specific high-valued UTF-8 characters, in this case we have to set the bits for
623 ph10 545 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
624 ph10 539 0xc0 (192) for simplicity.
625    
626     Arguments:
627     start_bits the starting bitmap
628     cbit type the type of character wanted
629     table_limit 32 for non-UTF-8; 16 for UTF-8
630 ph10 545 cd the block with char table pointers
631 ph10 539
632     Returns: nothing
633     */
634    
635     static void
636     set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
637     compile_data *cd)
638     {
639 ph10 545 register int c;
640 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
641     if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
642     }
643    
644    
645    
646     /*************************************************
647 nigel 93 * Create bitmap of starting bytes *
648 nigel 77 *************************************************/
649    
650 nigel 93 /* This function scans a compiled unanchored expression recursively and
651     attempts to build a bitmap of the set of possible starting bytes. As time goes
652     by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
653     useful for parenthesized groups in patterns such as (a*)b where the group
654     provides some optional starting bytes but scanning must continue at the outer
655     level to find at least one mandatory byte. At the outermost level, this
656     function fails unless the result is SSB_DONE.
657 nigel 77
658     Arguments:
659     code points to an expression
660     start_bits points to a 32-byte table, initialized to 0
661     utf8 TRUE if in UTF-8 mode
662     cd the block with char table pointers
663    
664 nigel 93 Returns: SSB_FAIL => Failed to find any starting bytes
665     SSB_DONE => Found mandatory starting bytes
666     SSB_CONTINUE => Found optional starting bytes
667 ph10 605 SSB_UNKNOWN => Hit an unrecognized opcode
668 nigel 77 */
669    
670 nigel 93 static int
671 ph10 605 set_start_bits(const uschar *code, uschar *start_bits, BOOL utf8,
672 ph10 603 compile_data *cd)
673 nigel 77 {
674     register int c;
675 nigel 93 int yield = SSB_DONE;
676 ph10 538 int table_limit = utf8? 16:32;
677 nigel 77
678 nigel 91 #if 0
679     /* ========================================================================= */
680     /* The following comment and code was inserted in January 1999. In May 2006,
681     when it was observed to cause compiler warnings about unused values, I took it
682     out again. If anybody is still using OS/2, they will have to put it back
683     manually. */
684    
685 nigel 77 /* This next statement and the later reference to dummy are here in order to
686     trick the optimizer of the IBM C compiler for OS/2 into generating correct
687     code. Apparently IBM isn't going to fix the problem, and we would rather not
688     disable optimization (in this module it actually makes a big difference, and
689     the pcre module can use all the optimization it can get). */
690    
691     volatile int dummy;
692 nigel 91 /* ========================================================================= */
693     #endif
694 nigel 77
695     do
696     {
697     BOOL try_next = TRUE;
698 ph10 604 const uschar *tcode = code + 1 + LINK_SIZE;
699 ph10 605
700 ph10 604 if (*code == OP_CBRA || *code == OP_SCBRA ||
701     *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += 2;
702 nigel 77
703 nigel 93 while (try_next) /* Loop for items in this branch */
704 nigel 77 {
705 nigel 93 int rc;
706 ph10 612
707 nigel 93 switch(*tcode)
708 nigel 77 {
709 ph10 605 /* If we reach something we don't understand, it means a new opcode has
710     been created that hasn't been added to this code. Hopefully this problem
711     will be discovered during testing. */
712 nigel 77
713     default:
714 ph10 605 return SSB_UNKNOWN;
715    
716     /* Fail for a valid opcode that implies no starting bits. */
717    
718     case OP_ACCEPT:
719 ph10 654 case OP_ASSERT_ACCEPT:
720 ph10 605 case OP_ALLANY:
721     case OP_ANY:
722     case OP_ANYBYTE:
723     case OP_CIRC:
724 ph10 654 case OP_CIRCM:
725 ph10 605 case OP_CLOSE:
726     case OP_COMMIT:
727     case OP_COND:
728 ph10 654 case OP_CREF:
729 ph10 605 case OP_DEF:
730     case OP_DOLL:
731 ph10 654 case OP_DOLLM:
732 ph10 605 case OP_END:
733     case OP_EOD:
734 ph10 654 case OP_EODN:
735 ph10 605 case OP_EXTUNI:
736     case OP_FAIL:
737     case OP_MARK:
738     case OP_NCREF:
739     case OP_NOT:
740     case OP_NOTEXACT:
741     case OP_NOTEXACTI:
742 ph10 654 case OP_NOTI:
743 ph10 605 case OP_NOTMINPLUS:
744     case OP_NOTMINPLUSI:
745     case OP_NOTMINQUERY:
746     case OP_NOTMINQUERYI:
747     case OP_NOTMINSTAR:
748     case OP_NOTMINSTARI:
749     case OP_NOTMINUPTO:
750     case OP_NOTMINUPTOI:
751     case OP_NOTPLUS:
752     case OP_NOTPLUSI:
753     case OP_NOTPOSPLUS:
754     case OP_NOTPOSPLUSI:
755     case OP_NOTPOSQUERY:
756     case OP_NOTPOSQUERYI:
757     case OP_NOTPOSSTAR:
758     case OP_NOTPOSSTARI:
759     case OP_NOTPOSUPTO:
760     case OP_NOTPOSUPTOI:
761     case OP_NOTPROP:
762     case OP_NOTQUERY:
763     case OP_NOTQUERYI:
764     case OP_NOTSTAR:
765     case OP_NOTSTARI:
766     case OP_NOTUPTO:
767     case OP_NOTUPTOI:
768     case OP_NOT_HSPACE:
769     case OP_NOT_VSPACE:
770     case OP_NRREF:
771     case OP_PROP:
772     case OP_PRUNE:
773     case OP_PRUNE_ARG:
774     case OP_RECURSE:
775     case OP_REF:
776     case OP_REFI:
777     case OP_REVERSE:
778     case OP_RREF:
779 ph10 654 case OP_SCOND:
780 ph10 605 case OP_SET_SOM:
781     case OP_SKIP:
782     case OP_SKIP_ARG:
783     case OP_SOD:
784     case OP_SOM:
785     case OP_THEN:
786     case OP_THEN_ARG:
787     case OP_XCLASS:
788 nigel 93 return SSB_FAIL;
789 nigel 77
790 ph10 657 /* We can ignore word boundary tests. */
791 ph10 659
792 ph10 657 case OP_WORD_BOUNDARY:
793     case OP_NOT_WORD_BOUNDARY:
794 ph10 659 tcode++;
795     break;
796 ph10 657
797 nigel 93 /* If we hit a bracket or a positive lookahead assertion, recurse to set
798     bits from within the subpattern. If it can't find anything, we have to
799     give up. If it finds some mandatory character(s), we are done for this
800     branch. Otherwise, carry on scanning after the subpattern. */
801    
802     case OP_BRA:
803     case OP_SBRA:
804     case OP_CBRA:
805     case OP_SCBRA:
806 ph10 604 case OP_BRAPOS:
807     case OP_SBRAPOS:
808     case OP_CBRAPOS:
809     case OP_SCBRAPOS:
810 nigel 93 case OP_ONCE:
811 ph10 723 case OP_ONCE_NC:
812 nigel 93 case OP_ASSERT:
813 ph10 603 rc = set_start_bits(tcode, start_bits, utf8, cd);
814 ph10 605 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
815 nigel 93 if (rc == SSB_DONE) try_next = FALSE; else
816     {
817     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
818     tcode += 1 + LINK_SIZE;
819     }
820     break;
821    
822     /* If we hit ALT or KET, it means we haven't found anything mandatory in
823     this branch, though we might have found something optional. For ALT, we
824     continue with the next alternative, but we have to arrange that the final
825     result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
826     return SSB_CONTINUE: if this is the top level, that indicates failure,
827     but after a nested subpattern, it causes scanning to continue. */
828    
829     case OP_ALT:
830     yield = SSB_CONTINUE;
831     try_next = FALSE;
832     break;
833    
834     case OP_KET:
835     case OP_KETRMAX:
836     case OP_KETRMIN:
837 ph10 605 case OP_KETRPOS:
838 nigel 93 return SSB_CONTINUE;
839    
840 nigel 77 /* Skip over callout */
841    
842     case OP_CALLOUT:
843     tcode += 2 + 2*LINK_SIZE;
844     break;
845    
846     /* Skip over lookbehind and negative lookahead assertions */
847    
848     case OP_ASSERT_NOT:
849     case OP_ASSERTBACK:
850     case OP_ASSERTBACK_NOT:
851     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
852 nigel 93 tcode += 1 + LINK_SIZE;
853 nigel 77 break;
854    
855     /* BRAZERO does the bracket, but carries on. */
856    
857     case OP_BRAZERO:
858     case OP_BRAMINZERO:
859 ph10 604 case OP_BRAPOSZERO:
860 ph10 605 rc = set_start_bits(++tcode, start_bits, utf8, cd);
861     if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
862 nigel 91 /* =========================================================================
863     See the comment at the head of this function concerning the next line,
864     which was an old fudge for the benefit of OS/2.
865 nigel 77 dummy = 1;
866 nigel 91 ========================================================================= */
867 nigel 77 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
868 nigel 93 tcode += 1 + LINK_SIZE;
869 nigel 77 break;
870    
871 ph10 335 /* SKIPZERO skips the bracket. */
872    
873     case OP_SKIPZERO:
874 ph10 358 tcode++;
875 ph10 335 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
876     tcode += 1 + LINK_SIZE;
877     break;
878    
879 nigel 77 /* Single-char * or ? sets the bit and tries the next item */
880    
881     case OP_STAR:
882     case OP_MINSTAR:
883 nigel 93 case OP_POSSTAR:
884 nigel 77 case OP_QUERY:
885     case OP_MINQUERY:
886 nigel 93 case OP_POSQUERY:
887 ph10 603 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
888 nigel 77 break;
889    
890 ph10 602 case OP_STARI:
891     case OP_MINSTARI:
892     case OP_POSSTARI:
893     case OP_QUERYI:
894     case OP_MINQUERYI:
895     case OP_POSQUERYI:
896     tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
897     break;
898    
899 nigel 77 /* Single-char upto sets the bit and tries the next */
900    
901     case OP_UPTO:
902     case OP_MINUPTO:
903 nigel 93 case OP_POSUPTO:
904 ph10 603 tcode = set_table_bit(start_bits, tcode + 3, FALSE, cd, utf8);
905 nigel 77 break;
906    
907 ph10 602 case OP_UPTOI:
908     case OP_MINUPTOI:
909     case OP_POSUPTOI:
910     tcode = set_table_bit(start_bits, tcode + 3, TRUE, cd, utf8);
911     break;
912    
913 nigel 77 /* At least one single char sets the bit and stops */
914    
915 ph10 602 case OP_EXACT:
916 nigel 77 tcode += 2;
917 ph10 602 /* Fall through */
918 nigel 77 case OP_CHAR:
919     case OP_PLUS:
920     case OP_MINPLUS:
921 nigel 93 case OP_POSPLUS:
922 ph10 603 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
923 nigel 77 try_next = FALSE;
924     break;
925 ph10 535
926 ph10 603 case OP_EXACTI:
927     tcode += 2;
928     /* Fall through */
929 ph10 602 case OP_CHARI:
930     case OP_PLUSI:
931     case OP_MINPLUSI:
932     case OP_POSPLUSI:
933     (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
934     try_next = FALSE;
935     break;
936    
937 ph10 535 /* Special spacing and line-terminating items. These recognize specific
938     lists of characters. The difference between VSPACE and ANYNL is that the
939     latter can match the two-character CRLF sequence, but that is not
940     relevant for finding the first character, so their code here is
941 ph10 524 identical. */
942 ph10 535
943 ph10 524 case OP_HSPACE:
944     SET_BIT(0x09);
945     SET_BIT(0x20);
946     if (utf8)
947 ph10 535 {
948 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
949 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
950     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
951 ph10 535 SET_BIT(0xE3); /* For U+3000 */
952 ph10 524 }
953 ph10 538 else SET_BIT(0xA0);
954 ph10 524 try_next = FALSE;
955 ph10 535 break;
956 nigel 77
957 ph10 535 case OP_ANYNL:
958 ph10 524 case OP_VSPACE:
959 ph10 535 SET_BIT(0x0A);
960     SET_BIT(0x0B);
961     SET_BIT(0x0C);
962     SET_BIT(0x0D);
963 ph10 545 if (utf8)
964     {
965     SET_BIT(0xC2); /* For U+0085 */
966 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
967 ph10 545 }
968 ph10 538 else SET_BIT(0x85);
969 ph10 524 try_next = FALSE;
970 ph10 535 break;
971 ph10 524
972 ph10 535 /* Single character types set the bits and stop. Note that if PCRE_UCP
973     is set, we do not see these op codes because \d etc are converted to
974 ph10 545 properties. Therefore, these apply in the case when only characters less
975 ph10 539 than 256 are recognized to match the types. */
976 nigel 77
977     case OP_NOT_DIGIT:
978 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
979 nigel 77 try_next = FALSE;
980     break;
981    
982     case OP_DIGIT:
983 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
984 nigel 77 try_next = FALSE;
985     break;
986    
987 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
988 ph10 539 ensure it is set as not whitespace. */
989 nigel 91
990 nigel 77 case OP_NOT_WHITESPACE:
991 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
992     start_bits[1] |= 0x08;
993 nigel 77 try_next = FALSE;
994     break;
995    
996 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
997 ph10 539 not set it from the table. */
998 nigel 91
999 nigel 77 case OP_WHITESPACE:
1000 ph10 539 c = start_bits[1]; /* Save in case it was already set */
1001     set_type_bits(start_bits, cbit_space, table_limit, cd);
1002     start_bits[1] = (start_bits[1] & ~0x08) | c;
1003 nigel 77 try_next = FALSE;
1004     break;
1005    
1006     case OP_NOT_WORDCHAR:
1007 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1008 nigel 77 try_next = FALSE;
1009     break;
1010    
1011     case OP_WORDCHAR:
1012 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
1013 nigel 77 try_next = FALSE;
1014     break;
1015 ph10 545
1016 nigel 77 /* One or more character type fudges the pointer and restarts, knowing
1017     it will hit a single character type and stop there. */
1018    
1019     case OP_TYPEPLUS:
1020     case OP_TYPEMINPLUS:
1021 ph10 535 case OP_TYPEPOSPLUS:
1022 nigel 77 tcode++;
1023     break;
1024    
1025     case OP_TYPEEXACT:
1026     tcode += 3;
1027     break;
1028    
1029     /* Zero or more repeats of character types set the bits and then
1030     try again. */
1031    
1032     case OP_TYPEUPTO:
1033     case OP_TYPEMINUPTO:
1034 nigel 93 case OP_TYPEPOSUPTO:
1035 nigel 77 tcode += 2; /* Fall through */
1036    
1037     case OP_TYPESTAR:
1038     case OP_TYPEMINSTAR:
1039 nigel 93 case OP_TYPEPOSSTAR:
1040 nigel 77 case OP_TYPEQUERY:
1041     case OP_TYPEMINQUERY:
1042 nigel 93 case OP_TYPEPOSQUERY:
1043 nigel 77 switch(tcode[1])
1044     {
1045 ph10 523 default:
1046 nigel 77 case OP_ANY:
1047 ph10 345 case OP_ALLANY:
1048 nigel 93 return SSB_FAIL;
1049 ph10 535
1050 ph10 524 case OP_HSPACE:
1051     SET_BIT(0x09);
1052     SET_BIT(0x20);
1053     if (utf8)
1054 ph10 535 {
1055 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
1056 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
1057     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1058 ph10 535 SET_BIT(0xE3); /* For U+3000 */
1059 ph10 524 }
1060 ph10 538 else SET_BIT(0xA0);
1061 ph10 535 break;
1062    
1063     case OP_ANYNL:
1064 ph10 524 case OP_VSPACE:
1065 ph10 535 SET_BIT(0x0A);
1066     SET_BIT(0x0B);
1067     SET_BIT(0x0C);
1068     SET_BIT(0x0D);
1069 ph10 545 if (utf8)
1070 ph10 538 {
1071 ph10 545 SET_BIT(0xC2); /* For U+0085 */
1072 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
1073 ph10 545 }
1074 ph10 538 else SET_BIT(0x85);
1075 ph10 535 break;
1076    
1077 nigel 77 case OP_NOT_DIGIT:
1078 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1079 nigel 77 break;
1080    
1081     case OP_DIGIT:
1082 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1083 nigel 77 break;
1084    
1085 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
1086 ph10 539 ensure it gets set as not whitespace. */
1087 nigel 91
1088 nigel 77 case OP_NOT_WHITESPACE:
1089 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1090 ph10 545 start_bits[1] |= 0x08;
1091 nigel 77 break;
1092    
1093 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
1094 ph10 539 avoid setting it. */
1095 nigel 91
1096 nigel 77 case OP_WHITESPACE:
1097 ph10 539 c = start_bits[1]; /* Save in case it was already set */
1098     set_type_bits(start_bits, cbit_space, table_limit, cd);
1099     start_bits[1] = (start_bits[1] & ~0x08) | c;
1100 nigel 77 break;
1101    
1102     case OP_NOT_WORDCHAR:
1103 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1104 nigel 77 break;
1105    
1106     case OP_WORDCHAR:
1107 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
1108 nigel 77 break;
1109     }
1110    
1111     tcode += 2;
1112     break;
1113    
1114     /* Character class where all the information is in a bit map: set the
1115     bits and either carry on or not, according to the repeat count. If it was
1116     a negative class, and we are operating with UTF-8 characters, any byte
1117     with a value >= 0xc4 is a potentially valid starter because it starts a
1118     character with a value > 255. */
1119    
1120     case OP_NCLASS:
1121 ph10 111 #ifdef SUPPORT_UTF8
1122 nigel 77 if (utf8)
1123     {
1124     start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1125     memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1126     }
1127 ph10 111 #endif
1128 nigel 77 /* Fall through */
1129    
1130     case OP_CLASS:
1131     {
1132     tcode++;
1133    
1134     /* In UTF-8 mode, the bits in a bit map correspond to character
1135     values, not to byte values. However, the bit map we are constructing is
1136     for byte values. So we have to do a conversion for characters whose
1137     value is > 127. In fact, there are only two possible starting bytes for
1138     characters in the range 128 - 255. */
1139    
1140 ph10 107 #ifdef SUPPORT_UTF8
1141 nigel 77 if (utf8)
1142     {
1143     for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
1144     for (c = 128; c < 256; c++)
1145     {
1146     if ((tcode[c/8] && (1 << (c&7))) != 0)
1147     {
1148     int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1149     start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1150     c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1151     }
1152     }
1153     }
1154    
1155     /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1156    
1157     else
1158 ph10 111 #endif
1159 nigel 77 {
1160     for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
1161     }
1162    
1163 ph10 654 /* Advance past the bit map, and act on what follows. For a zero
1164 ph10 605 minimum repeat, continue; otherwise stop processing. */
1165 nigel 77
1166     tcode += 32;
1167     switch (*tcode)
1168     {
1169     case OP_CRSTAR:
1170     case OP_CRMINSTAR:
1171     case OP_CRQUERY:
1172     case OP_CRMINQUERY:
1173     tcode++;
1174     break;
1175    
1176     case OP_CRRANGE:
1177     case OP_CRMINRANGE:
1178     if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
1179     else try_next = FALSE;
1180     break;
1181 ph10 654
1182 nigel 77 default:
1183     try_next = FALSE;
1184     break;
1185     }
1186     }
1187     break; /* End of bitmap class handling */
1188    
1189     } /* End of switch */
1190     } /* End of try_next loop */
1191    
1192     code += GET(code, 1); /* Advance to next branch */
1193     }
1194     while (*code == OP_ALT);
1195 nigel 93 return yield;
1196 nigel 77 }
1197    
1198    
1199    
1200 ph10 605
1201    
1202 nigel 77 /*************************************************
1203     * Study a compiled expression *
1204     *************************************************/
1205    
1206     /* This function is handed a compiled expression that it must study to produce
1207     information that will speed up the matching. It returns a pcre_extra block
1208     which then gets handed back to pcre_exec().
1209    
1210     Arguments:
1211     re points to the compiled expression
1212     options contains option bits
1213     errorptr points to where to place error messages;
1214     set NULL unless error
1215    
1216     Returns: pointer to a pcre_extra block, with study_data filled in and the
1217 ph10 455 appropriate flags set;
1218 nigel 77 NULL on error or if no optimization possible
1219     */
1220    
1221 ph10 359 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1222 nigel 77 pcre_study(const pcre *external_re, int options, const char **errorptr)
1223     {
1224 ph10 455 int min;
1225     BOOL bits_set = FALSE;
1226 nigel 77 uschar start_bits[32];
1227 ph10 688 pcre_extra *extra = NULL;
1228 nigel 77 pcre_study_data *study;
1229     const uschar *tables;
1230 nigel 91 uschar *code;
1231     compile_data compile_block;
1232 nigel 77 const real_pcre *re = (const real_pcre *)external_re;
1233    
1234     *errorptr = NULL;
1235    
1236     if (re == NULL || re->magic_number != MAGIC_NUMBER)
1237     {
1238     *errorptr = "argument is not a compiled regular expression";
1239     return NULL;
1240     }
1241    
1242     if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1243     {
1244     *errorptr = "unknown or incorrect option bit(s) set";
1245     return NULL;
1246     }
1247    
1248 nigel 91 code = (uschar *)re + re->name_table_offset +
1249     (re->name_count * re->name_entry_size);
1250    
1251 nigel 77 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1252 ph10 461 a multiline pattern that matches only at "line starts", there is no point in
1253 ph10 455 seeking a list of starting bytes. */
1254 nigel 77
1255 ph10 455 if ((re->options & PCRE_ANCHORED) == 0 &&
1256     (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1257     {
1258 ph10 605 int rc;
1259    
1260 ph10 455 /* Set the character tables in the block that is passed around */
1261 ph10 461
1262 ph10 455 tables = re->tables;
1263     if (tables == NULL)
1264     (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1265     (void *)(&tables));
1266 ph10 461
1267 ph10 455 compile_block.lcc = tables + lcc_offset;
1268     compile_block.fcc = tables + fcc_offset;
1269     compile_block.cbits = tables + cbits_offset;
1270     compile_block.ctypes = tables + ctypes_offset;
1271 ph10 461
1272 ph10 455 /* See if we can find a fixed set of initial characters for the pattern. */
1273 ph10 461
1274 ph10 455 memset(start_bits, 0, 32 * sizeof(uschar));
1275 ph10 605 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1276     &compile_block);
1277     bits_set = rc == SSB_DONE;
1278 ph10 691 if (rc == SSB_UNKNOWN)
1279 ph10 688 {
1280     *errorptr = "internal error: opcode not recognized";
1281     return NULL;
1282 ph10 691 }
1283 ph10 455 }
1284 ph10 461
1285 ph10 455 /* Find the minimum length of subject string. */
1286 nigel 77
1287 ph10 697 switch(min = find_minlength(code, code, re->options, 0))
1288 ph10 603 {
1289 ph10 688 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1290     case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1291 ph10 603 default: break;
1292 ph10 605 }
1293 ph10 708
1294 ph10 688 /* If a set of starting bytes has been identified, or if the minimum length is
1295     greater than zero, or if JIT optimization has been requested, get a pcre_extra
1296     block and a pcre_study_data block. The study data is put in the latter, which
1297     is pointed to by the former, which may also get additional data set later by
1298     the calling program. At the moment, the size of pcre_study_data is fixed. We
1299     nevertheless save it in a field for returning via the pcre_fullinfo() function
1300     so that if it becomes variable in the future, we don't have to change that
1301     code. */
1302 nigel 77
1303 ph10 691 if (bits_set || min > 0
1304 ph10 688 #ifdef SUPPORT_JIT
1305     || (options & PCRE_STUDY_JIT_COMPILE) != 0
1306     #endif
1307     )
1308 nigel 77 {
1309 ph10 688 extra = (pcre_extra *)(pcre_malloc)
1310     (sizeof(pcre_extra) + sizeof(pcre_study_data));
1311     if (extra == NULL)
1312     {
1313     *errorptr = "failed to get memory";
1314     return NULL;
1315     }
1316 ph10 691
1317 ph10 688 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1318     extra->flags = PCRE_EXTRA_STUDY_DATA;
1319     extra->study_data = study;
1320 ph10 691
1321 ph10 688 study->size = sizeof(pcre_study_data);
1322     study->flags = 0;
1323 ph10 691
1324 ph10 688 if (bits_set)
1325     {
1326     study->flags |= PCRE_STUDY_MAPPED;
1327     memcpy(study->start_bits, start_bits, sizeof(start_bits));
1328     }
1329 ph10 691
1330     /* Always set the minlength value in the block, because the JIT compiler
1331     makes use of it. However, don't set the bit unless the length is greater than
1332     zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1333 ph10 697 checking the zero case. */
1334 ph10 691
1335 ph10 708 if (min > 0)
1336 ph10 697 {
1337     study->flags |= PCRE_STUDY_MINLEN;
1338     study->minlength = min;
1339     }
1340 ph10 708 else study->minlength = 0;
1341 ph10 691
1342 ph10 688 /* If JIT support was compiled and requested, attempt the JIT compilation.
1343     If no starting bytes were found, and the minimum length is zero, and JIT
1344 ph10 689 compilation fails, abandon the extra block and return NULL. */
1345 ph10 691
1346 ph10 666 #ifdef SUPPORT_JIT
1347 ph10 688 extra->executable_jit = NULL;
1348     if ((options & PCRE_STUDY_JIT_COMPILE) != 0) _pcre_jit_compile(re, extra);
1349 ph10 689 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0)
1350 ph10 688 {
1351     pcre_free_study(extra);
1352     extra = NULL;
1353 ph10 691 }
1354 ph10 666 #endif
1355 ph10 688 }
1356 ph10 666
1357 nigel 77 return extra;
1358     }
1359    
1360 ph10 666
1361     /*************************************************
1362     * Free the study data *
1363     *************************************************/
1364    
1365     /* This function frees the memory that was obtained by pcre_study().
1366    
1367     Argument: a pointer to the pcre_extra block
1368     Returns: nothing
1369     */
1370    
1371     PCRE_EXP_DEFN void
1372     pcre_free_study(pcre_extra *extra)
1373     {
1374     #ifdef SUPPORT_JIT
1375 ph10 691 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1376 ph10 666 extra->executable_jit != NULL)
1377     _pcre_jit_free(extra->executable_jit);
1378     #endif
1379     pcre_free(extra);
1380     }
1381    
1382 nigel 77 /* End of pcre_study.c */

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