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Revision 459 - (hide annotations) (download)
Sun Oct 4 09:21:39 2009 UTC (5 years, 2 months ago) by ph10
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File size: 26882 byte(s)
Fix problems with conditional references to duplicate named subpatterns.

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 455 Copyright (c) 1997-2009 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    
52 nigel 93 /* Returns from set_start_bits() */
53    
54     enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE };
55    
56    
57 ph10 455
58 nigel 77 /*************************************************
59 ph10 455 * Find the minimum subject length for a group *
60     *************************************************/
61    
62     /* Scan a parenthesized group and compute the minimum length of subject that
63     is needed to match it. This is a lower bound; it does not mean there is a
64     string of that length that matches. In UTF8 mode, the result is in characters
65     rather than bytes.
66    
67     Arguments:
68     code pointer to start of group (the bracket)
69     startcode pointer to start of the whole pattern
70     options the compiling options
71    
72     Returns: the minimum length
73     -1 if \C was encountered
74     -2 internal error (missing capturing bracket)
75     */
76    
77     static int
78     find_minlength(const uschar *code, const uschar *startcode, int options)
79     {
80     int length = -1;
81     BOOL utf8 = (options & PCRE_UTF8) != 0;
82     BOOL had_recurse = FALSE;
83     register int branchlength = 0;
84     register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
85    
86     if (*code == OP_CBRA || *code == OP_SCBRA) cc += 2;
87    
88     /* Scan along the opcodes for this branch. If we get to the end of the
89     branch, check the length against that of the other branches. */
90    
91     for (;;)
92     {
93     int d, min;
94     uschar *cs, *ce;
95     register int op = *cc;
96    
97     switch (op)
98     {
99     case OP_CBRA:
100     case OP_SCBRA:
101     case OP_BRA:
102     case OP_SBRA:
103     case OP_ONCE:
104     case OP_COND:
105     case OP_SCOND:
106     d = find_minlength(cc, startcode, options);
107     if (d < 0) return d;
108     branchlength += d;
109     do cc += GET(cc, 1); while (*cc == OP_ALT);
110     cc += 1 + LINK_SIZE;
111     break;
112    
113     /* Reached end of a branch; if it's a ket it is the end of a nested
114     call. If it's ALT it is an alternation in a nested call. If it is
115     END it's the end of the outer call. All can be handled by the same code. */
116    
117     case OP_ALT:
118     case OP_KET:
119     case OP_KETRMAX:
120     case OP_KETRMIN:
121     case OP_END:
122     if (length < 0 || (!had_recurse && branchlength < length))
123     length = branchlength;
124     if (*cc != OP_ALT) return length;
125     cc += 1 + LINK_SIZE;
126     branchlength = 0;
127     had_recurse = FALSE;
128     break;
129    
130     /* Skip over assertive subpatterns */
131    
132     case OP_ASSERT:
133     case OP_ASSERT_NOT:
134     case OP_ASSERTBACK:
135     case OP_ASSERTBACK_NOT:
136     do cc += GET(cc, 1); while (*cc == OP_ALT);
137     /* Fall through */
138    
139     /* Skip over things that don't match chars */
140    
141     case OP_REVERSE:
142     case OP_CREF:
143 ph10 459 case OP_NCREF:
144 ph10 455 case OP_RREF:
145 ph10 459 case OP_NRREF:
146 ph10 455 case OP_DEF:
147     case OP_OPT:
148     case OP_CALLOUT:
149     case OP_SOD:
150     case OP_SOM:
151     case OP_EOD:
152     case OP_EODN:
153     case OP_CIRC:
154     case OP_DOLL:
155     case OP_NOT_WORD_BOUNDARY:
156     case OP_WORD_BOUNDARY:
157     cc += _pcre_OP_lengths[*cc];
158     break;
159    
160     /* Skip over a subpattern that has a {0} or {0,x} quantifier */
161    
162     case OP_BRAZERO:
163     case OP_BRAMINZERO:
164     case OP_SKIPZERO:
165     cc += _pcre_OP_lengths[*cc];
166     do cc += GET(cc, 1); while (*cc == OP_ALT);
167     cc += 1 + LINK_SIZE;
168     break;
169    
170     /* Handle literal characters and + repetitions */
171    
172     case OP_CHAR:
173     case OP_CHARNC:
174     case OP_NOT:
175     case OP_PLUS:
176     case OP_MINPLUS:
177     case OP_POSPLUS:
178     case OP_NOTPLUS:
179     case OP_NOTMINPLUS:
180     case OP_NOTPOSPLUS:
181     branchlength++;
182     cc += 2;
183     #ifdef SUPPORT_UTF8
184     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
185     #endif
186     break;
187    
188     case OP_TYPEPLUS:
189     case OP_TYPEMINPLUS:
190     case OP_TYPEPOSPLUS:
191     branchlength++;
192     cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
193     break;
194    
195     /* Handle exact repetitions. The count is already in characters, but we
196     need to skip over a multibyte character in UTF8 mode. */
197    
198     case OP_EXACT:
199     case OP_NOTEXACT:
200     branchlength += GET2(cc,1);
201     cc += 4;
202     #ifdef SUPPORT_UTF8
203     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
204     #endif
205     break;
206    
207     case OP_TYPEEXACT:
208     branchlength += GET2(cc,1);
209     cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
210     break;
211    
212     /* Handle single-char non-literal matchers */
213    
214     case OP_PROP:
215     case OP_NOTPROP:
216     cc += 2;
217     /* Fall through */
218    
219     case OP_NOT_DIGIT:
220     case OP_DIGIT:
221     case OP_NOT_WHITESPACE:
222     case OP_WHITESPACE:
223     case OP_NOT_WORDCHAR:
224     case OP_WORDCHAR:
225     case OP_ANY:
226     case OP_ALLANY:
227     case OP_EXTUNI:
228     case OP_HSPACE:
229     case OP_NOT_HSPACE:
230     case OP_VSPACE:
231     case OP_NOT_VSPACE:
232     branchlength++;
233     cc++;
234     break;
235    
236     /* "Any newline" might match two characters */
237    
238     case OP_ANYNL:
239     branchlength += 2;
240     cc++;
241     break;
242    
243     /* The single-byte matcher means we can't proceed in UTF-8 mode */
244    
245     case OP_ANYBYTE:
246     #ifdef SUPPORT_UTF8
247     if (utf8) return -1;
248     #endif
249     branchlength++;
250     cc++;
251     break;
252    
253     /* For repeated character types, we have to test for \p and \P, which have
254     an extra two bytes of parameters. */
255    
256     case OP_TYPESTAR:
257     case OP_TYPEMINSTAR:
258     case OP_TYPEQUERY:
259     case OP_TYPEMINQUERY:
260     case OP_TYPEPOSSTAR:
261     case OP_TYPEPOSQUERY:
262     if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
263     cc += _pcre_OP_lengths[op];
264     break;
265    
266     case OP_TYPEUPTO:
267     case OP_TYPEMINUPTO:
268     case OP_TYPEPOSUPTO:
269     if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
270     cc += _pcre_OP_lengths[op];
271     break;
272    
273     /* Check a class for variable quantification */
274    
275     #ifdef SUPPORT_UTF8
276     case OP_XCLASS:
277     cc += GET(cc, 1) - 33;
278     /* Fall through */
279     #endif
280    
281     case OP_CLASS:
282     case OP_NCLASS:
283     cc += 33;
284    
285     switch (*cc)
286     {
287     case OP_CRPLUS:
288     case OP_CRMINPLUS:
289     branchlength++;
290     /* Fall through */
291    
292     case OP_CRSTAR:
293     case OP_CRMINSTAR:
294     case OP_CRQUERY:
295     case OP_CRMINQUERY:
296     cc++;
297     break;
298    
299     case OP_CRRANGE:
300     case OP_CRMINRANGE:
301     branchlength += GET2(cc,1);
302     cc += 5;
303     break;
304    
305     default:
306     branchlength++;
307     break;
308     }
309     break;
310    
311     /* Backreferences and subroutine calls are treated in the same way: we find
312     the minimum length for the subpattern. A recursion, however, causes an
313     a flag to be set that causes the length of this branch to be ignored. The
314     logic is that a recursion can only make sense if there is another
315     alternation that stops the recursing. That will provide the minimum length
316     (when no recursion happens). A backreference within the group that it is
317     referencing behaves in the same way. */
318    
319     case OP_REF:
320     ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
321     if (cs == NULL) return -2;
322     do ce += GET(ce, 1); while (*ce == OP_ALT);
323     if (cc > cs && cc < ce)
324     {
325     d = 0;
326     had_recurse = TRUE;
327     }
328     else d = find_minlength(cs, startcode, options);
329     cc += 3;
330    
331     /* Handle repeated back references */
332    
333     switch (*cc)
334     {
335     case OP_CRSTAR:
336     case OP_CRMINSTAR:
337     case OP_CRQUERY:
338     case OP_CRMINQUERY:
339     min = 0;
340     cc++;
341     break;
342    
343     case OP_CRRANGE:
344     case OP_CRMINRANGE:
345     min = GET2(cc, 1);
346     cc += 5;
347     break;
348    
349     default:
350     min = 1;
351     break;
352     }
353    
354     branchlength += min * d;
355     break;
356    
357     case OP_RECURSE:
358     cs = ce = (uschar *)startcode + GET(cc, 1);
359     if (cs == NULL) return -2;
360     do ce += GET(ce, 1); while (*ce == OP_ALT);
361     if (cc > cs && cc < ce)
362     had_recurse = TRUE;
363     else
364     branchlength += find_minlength(cs, startcode, options);
365     cc += 1 + LINK_SIZE;
366     break;
367    
368     /* Anything else does not or need not match a character. We can get the
369     item's length from the table, but for those that can match zero occurrences
370     of a character, we must take special action for UTF-8 characters. */
371    
372     case OP_UPTO:
373     case OP_NOTUPTO:
374     case OP_MINUPTO:
375     case OP_NOTMINUPTO:
376     case OP_POSUPTO:
377     case OP_STAR:
378     case OP_MINSTAR:
379     case OP_NOTMINSTAR:
380     case OP_POSSTAR:
381     case OP_NOTPOSSTAR:
382     case OP_QUERY:
383     case OP_MINQUERY:
384     case OP_NOTMINQUERY:
385     case OP_POSQUERY:
386     case OP_NOTPOSQUERY:
387     cc += _pcre_OP_lengths[op];
388     #ifdef SUPPORT_UTF8
389     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
390     #endif
391     break;
392    
393     /* For the record, these are the opcodes that are matched by "default":
394     OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
395     OP_THEN. */
396    
397     default:
398     cc += _pcre_OP_lengths[op];
399     break;
400     }
401     }
402     /* Control never gets here */
403     }
404    
405    
406    
407     /*************************************************
408 nigel 77 * Set a bit and maybe its alternate case *
409     *************************************************/
410    
411     /* Given a character, set its bit in the table, and also the bit for the other
412     version of a letter if we are caseless.
413    
414     Arguments:
415     start_bits points to the bit map
416     c is the character
417     caseless the caseless flag
418     cd the block with char table pointers
419    
420     Returns: nothing
421     */
422    
423     static void
424     set_bit(uschar *start_bits, unsigned int c, BOOL caseless, compile_data *cd)
425     {
426     start_bits[c/8] |= (1 << (c&7));
427     if (caseless && (cd->ctypes[c] & ctype_letter) != 0)
428     start_bits[cd->fcc[c]/8] |= (1 << (cd->fcc[c]&7));
429     }
430    
431    
432    
433     /*************************************************
434 nigel 93 * Create bitmap of starting bytes *
435 nigel 77 *************************************************/
436    
437 nigel 93 /* This function scans a compiled unanchored expression recursively and
438     attempts to build a bitmap of the set of possible starting bytes. As time goes
439     by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
440     useful for parenthesized groups in patterns such as (a*)b where the group
441     provides some optional starting bytes but scanning must continue at the outer
442     level to find at least one mandatory byte. At the outermost level, this
443     function fails unless the result is SSB_DONE.
444 nigel 77
445     Arguments:
446     code points to an expression
447     start_bits points to a 32-byte table, initialized to 0
448     caseless the current state of the caseless flag
449     utf8 TRUE if in UTF-8 mode
450     cd the block with char table pointers
451    
452 nigel 93 Returns: SSB_FAIL => Failed to find any starting bytes
453     SSB_DONE => Found mandatory starting bytes
454     SSB_CONTINUE => Found optional starting bytes
455 nigel 77 */
456    
457 nigel 93 static int
458 nigel 77 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
459     BOOL utf8, compile_data *cd)
460     {
461     register int c;
462 nigel 93 int yield = SSB_DONE;
463 nigel 77
464 nigel 91 #if 0
465     /* ========================================================================= */
466     /* The following comment and code was inserted in January 1999. In May 2006,
467     when it was observed to cause compiler warnings about unused values, I took it
468     out again. If anybody is still using OS/2, they will have to put it back
469     manually. */
470    
471 nigel 77 /* This next statement and the later reference to dummy are here in order to
472     trick the optimizer of the IBM C compiler for OS/2 into generating correct
473     code. Apparently IBM isn't going to fix the problem, and we would rather not
474     disable optimization (in this module it actually makes a big difference, and
475     the pcre module can use all the optimization it can get). */
476    
477     volatile int dummy;
478 nigel 91 /* ========================================================================= */
479     #endif
480 nigel 77
481     do
482     {
483 nigel 93 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
484 nigel 77 BOOL try_next = TRUE;
485    
486 nigel 93 while (try_next) /* Loop for items in this branch */
487 nigel 77 {
488 nigel 93 int rc;
489     switch(*tcode)
490 nigel 77 {
491 nigel 93 /* Fail if we reach something we don't understand */
492 nigel 77
493     default:
494 nigel 93 return SSB_FAIL;
495 nigel 77
496 nigel 93 /* If we hit a bracket or a positive lookahead assertion, recurse to set
497     bits from within the subpattern. If it can't find anything, we have to
498     give up. If it finds some mandatory character(s), we are done for this
499     branch. Otherwise, carry on scanning after the subpattern. */
500    
501     case OP_BRA:
502     case OP_SBRA:
503     case OP_CBRA:
504     case OP_SCBRA:
505     case OP_ONCE:
506     case OP_ASSERT:
507     rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
508     if (rc == SSB_FAIL) return SSB_FAIL;
509     if (rc == SSB_DONE) try_next = FALSE; else
510     {
511     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
512     tcode += 1 + LINK_SIZE;
513     }
514     break;
515    
516     /* If we hit ALT or KET, it means we haven't found anything mandatory in
517     this branch, though we might have found something optional. For ALT, we
518     continue with the next alternative, but we have to arrange that the final
519     result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
520     return SSB_CONTINUE: if this is the top level, that indicates failure,
521     but after a nested subpattern, it causes scanning to continue. */
522    
523     case OP_ALT:
524     yield = SSB_CONTINUE;
525     try_next = FALSE;
526     break;
527    
528     case OP_KET:
529     case OP_KETRMAX:
530     case OP_KETRMIN:
531     return SSB_CONTINUE;
532    
533 nigel 77 /* Skip over callout */
534    
535     case OP_CALLOUT:
536     tcode += 2 + 2*LINK_SIZE;
537     break;
538    
539     /* Skip over lookbehind and negative lookahead assertions */
540    
541     case OP_ASSERT_NOT:
542     case OP_ASSERTBACK:
543     case OP_ASSERTBACK_NOT:
544     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
545 nigel 93 tcode += 1 + LINK_SIZE;
546 nigel 77 break;
547    
548     /* Skip over an option setting, changing the caseless flag */
549    
550     case OP_OPT:
551     caseless = (tcode[1] & PCRE_CASELESS) != 0;
552     tcode += 2;
553     break;
554    
555     /* BRAZERO does the bracket, but carries on. */
556    
557     case OP_BRAZERO:
558     case OP_BRAMINZERO:
559 nigel 93 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
560     return SSB_FAIL;
561 nigel 91 /* =========================================================================
562     See the comment at the head of this function concerning the next line,
563     which was an old fudge for the benefit of OS/2.
564 nigel 77 dummy = 1;
565 nigel 91 ========================================================================= */
566 nigel 77 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
567 nigel 93 tcode += 1 + LINK_SIZE;
568 nigel 77 break;
569    
570 ph10 335 /* SKIPZERO skips the bracket. */
571    
572     case OP_SKIPZERO:
573 ph10 358 tcode++;
574 ph10 335 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
575     tcode += 1 + LINK_SIZE;
576     break;
577    
578 nigel 77 /* Single-char * or ? sets the bit and tries the next item */
579    
580     case OP_STAR:
581     case OP_MINSTAR:
582 nigel 93 case OP_POSSTAR:
583 nigel 77 case OP_QUERY:
584     case OP_MINQUERY:
585 nigel 93 case OP_POSQUERY:
586 nigel 77 set_bit(start_bits, tcode[1], caseless, cd);
587     tcode += 2;
588     #ifdef SUPPORT_UTF8
589 nigel 93 if (utf8 && tcode[-1] >= 0xc0)
590     tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
591 nigel 77 #endif
592     break;
593    
594     /* Single-char upto sets the bit and tries the next */
595    
596     case OP_UPTO:
597     case OP_MINUPTO:
598 nigel 93 case OP_POSUPTO:
599 nigel 77 set_bit(start_bits, tcode[3], caseless, cd);
600     tcode += 4;
601     #ifdef SUPPORT_UTF8
602 nigel 93 if (utf8 && tcode[-1] >= 0xc0)
603     tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
604 nigel 77 #endif
605     break;
606    
607     /* At least one single char sets the bit and stops */
608    
609     case OP_EXACT: /* Fall through */
610     tcode += 2;
611    
612     case OP_CHAR:
613     case OP_CHARNC:
614     case OP_PLUS:
615     case OP_MINPLUS:
616 nigel 93 case OP_POSPLUS:
617 nigel 77 set_bit(start_bits, tcode[1], caseless, cd);
618     try_next = FALSE;
619     break;
620    
621     /* Single character type sets the bits and stops */
622    
623     case OP_NOT_DIGIT:
624     for (c = 0; c < 32; c++)
625     start_bits[c] |= ~cd->cbits[c+cbit_digit];
626     try_next = FALSE;
627     break;
628    
629     case OP_DIGIT:
630     for (c = 0; c < 32; c++)
631     start_bits[c] |= cd->cbits[c+cbit_digit];
632     try_next = FALSE;
633     break;
634    
635 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
636     discard it. */
637    
638 nigel 77 case OP_NOT_WHITESPACE:
639     for (c = 0; c < 32; c++)
640 nigel 91 {
641     int d = cd->cbits[c+cbit_space];
642     if (c == 1) d &= ~0x08;
643     start_bits[c] |= ~d;
644     }
645 nigel 77 try_next = FALSE;
646     break;
647    
648 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
649     discard it. */
650    
651 nigel 77 case OP_WHITESPACE:
652     for (c = 0; c < 32; c++)
653 nigel 91 {
654     int d = cd->cbits[c+cbit_space];
655     if (c == 1) d &= ~0x08;
656     start_bits[c] |= d;
657     }
658 nigel 77 try_next = FALSE;
659     break;
660    
661     case OP_NOT_WORDCHAR:
662     for (c = 0; c < 32; c++)
663     start_bits[c] |= ~cd->cbits[c+cbit_word];
664     try_next = FALSE;
665     break;
666    
667     case OP_WORDCHAR:
668     for (c = 0; c < 32; c++)
669     start_bits[c] |= cd->cbits[c+cbit_word];
670     try_next = FALSE;
671     break;
672    
673     /* One or more character type fudges the pointer and restarts, knowing
674     it will hit a single character type and stop there. */
675    
676     case OP_TYPEPLUS:
677     case OP_TYPEMINPLUS:
678     tcode++;
679     break;
680    
681     case OP_TYPEEXACT:
682     tcode += 3;
683     break;
684    
685     /* Zero or more repeats of character types set the bits and then
686     try again. */
687    
688     case OP_TYPEUPTO:
689     case OP_TYPEMINUPTO:
690 nigel 93 case OP_TYPEPOSUPTO:
691 nigel 77 tcode += 2; /* Fall through */
692    
693     case OP_TYPESTAR:
694     case OP_TYPEMINSTAR:
695 nigel 93 case OP_TYPEPOSSTAR:
696 nigel 77 case OP_TYPEQUERY:
697     case OP_TYPEMINQUERY:
698 nigel 93 case OP_TYPEPOSQUERY:
699 nigel 77 switch(tcode[1])
700     {
701     case OP_ANY:
702 ph10 345 case OP_ALLANY:
703 nigel 93 return SSB_FAIL;
704 nigel 77
705     case OP_NOT_DIGIT:
706     for (c = 0; c < 32; c++)
707     start_bits[c] |= ~cd->cbits[c+cbit_digit];
708     break;
709    
710     case OP_DIGIT:
711     for (c = 0; c < 32; c++)
712     start_bits[c] |= cd->cbits[c+cbit_digit];
713     break;
714    
715 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
716     discard it. */
717    
718 nigel 77 case OP_NOT_WHITESPACE:
719     for (c = 0; c < 32; c++)
720 nigel 91 {
721     int d = cd->cbits[c+cbit_space];
722     if (c == 1) d &= ~0x08;
723     start_bits[c] |= ~d;
724     }
725 nigel 77 break;
726    
727 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
728     discard it. */
729    
730 nigel 77 case OP_WHITESPACE:
731     for (c = 0; c < 32; c++)
732 nigel 91 {
733     int d = cd->cbits[c+cbit_space];
734     if (c == 1) d &= ~0x08;
735     start_bits[c] |= d;
736     }
737 nigel 77 break;
738    
739     case OP_NOT_WORDCHAR:
740     for (c = 0; c < 32; c++)
741     start_bits[c] |= ~cd->cbits[c+cbit_word];
742     break;
743    
744     case OP_WORDCHAR:
745     for (c = 0; c < 32; c++)
746     start_bits[c] |= cd->cbits[c+cbit_word];
747     break;
748     }
749    
750     tcode += 2;
751     break;
752    
753     /* Character class where all the information is in a bit map: set the
754     bits and either carry on or not, according to the repeat count. If it was
755     a negative class, and we are operating with UTF-8 characters, any byte
756     with a value >= 0xc4 is a potentially valid starter because it starts a
757     character with a value > 255. */
758    
759     case OP_NCLASS:
760 ph10 111 #ifdef SUPPORT_UTF8
761 nigel 77 if (utf8)
762     {
763     start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
764     memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
765     }
766 ph10 111 #endif
767 nigel 77 /* Fall through */
768    
769     case OP_CLASS:
770     {
771     tcode++;
772    
773     /* In UTF-8 mode, the bits in a bit map correspond to character
774     values, not to byte values. However, the bit map we are constructing is
775     for byte values. So we have to do a conversion for characters whose
776     value is > 127. In fact, there are only two possible starting bytes for
777     characters in the range 128 - 255. */
778    
779 ph10 107 #ifdef SUPPORT_UTF8
780 nigel 77 if (utf8)
781     {
782     for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
783     for (c = 128; c < 256; c++)
784     {
785     if ((tcode[c/8] && (1 << (c&7))) != 0)
786     {
787     int d = (c >> 6) | 0xc0; /* Set bit for this starter */
788     start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
789     c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
790     }
791     }
792     }
793    
794     /* In non-UTF-8 mode, the two bit maps are completely compatible. */
795    
796     else
797 ph10 111 #endif
798 nigel 77 {
799     for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
800     }
801    
802     /* Advance past the bit map, and act on what follows */
803    
804     tcode += 32;
805     switch (*tcode)
806     {
807     case OP_CRSTAR:
808     case OP_CRMINSTAR:
809     case OP_CRQUERY:
810     case OP_CRMINQUERY:
811     tcode++;
812     break;
813    
814     case OP_CRRANGE:
815     case OP_CRMINRANGE:
816     if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
817     else try_next = FALSE;
818     break;
819    
820     default:
821     try_next = FALSE;
822     break;
823     }
824     }
825     break; /* End of bitmap class handling */
826    
827     } /* End of switch */
828     } /* End of try_next loop */
829    
830     code += GET(code, 1); /* Advance to next branch */
831     }
832     while (*code == OP_ALT);
833 nigel 93 return yield;
834 nigel 77 }
835    
836    
837    
838     /*************************************************
839     * Study a compiled expression *
840     *************************************************/
841    
842     /* This function is handed a compiled expression that it must study to produce
843     information that will speed up the matching. It returns a pcre_extra block
844     which then gets handed back to pcre_exec().
845    
846     Arguments:
847     re points to the compiled expression
848     options contains option bits
849     errorptr points to where to place error messages;
850     set NULL unless error
851    
852     Returns: pointer to a pcre_extra block, with study_data filled in and the
853 ph10 455 appropriate flags set;
854 nigel 77 NULL on error or if no optimization possible
855     */
856    
857 ph10 359 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
858 nigel 77 pcre_study(const pcre *external_re, int options, const char **errorptr)
859     {
860 ph10 455 int min;
861     BOOL bits_set = FALSE;
862 nigel 77 uschar start_bits[32];
863     pcre_extra *extra;
864     pcre_study_data *study;
865     const uschar *tables;
866 nigel 91 uschar *code;
867     compile_data compile_block;
868 nigel 77 const real_pcre *re = (const real_pcre *)external_re;
869    
870     *errorptr = NULL;
871    
872     if (re == NULL || re->magic_number != MAGIC_NUMBER)
873     {
874     *errorptr = "argument is not a compiled regular expression";
875     return NULL;
876     }
877    
878     if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
879     {
880     *errorptr = "unknown or incorrect option bit(s) set";
881     return NULL;
882     }
883    
884 nigel 91 code = (uschar *)re + re->name_table_offset +
885     (re->name_count * re->name_entry_size);
886    
887 nigel 77 /* For an anchored pattern, or an unanchored pattern that has a first char, or
888 ph10 455 a multiline pattern that matches only at "line starts", there is no point in
889     seeking a list of starting bytes. */
890 nigel 77
891 ph10 455 if ((re->options & PCRE_ANCHORED) == 0 &&
892     (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
893     {
894     /* Set the character tables in the block that is passed around */
895    
896     tables = re->tables;
897     if (tables == NULL)
898     (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
899     (void *)(&tables));
900    
901     compile_block.lcc = tables + lcc_offset;
902     compile_block.fcc = tables + fcc_offset;
903     compile_block.cbits = tables + cbits_offset;
904     compile_block.ctypes = tables + ctypes_offset;
905    
906     /* See if we can find a fixed set of initial characters for the pattern. */
907    
908     memset(start_bits, 0, 32 * sizeof(uschar));
909     bits_set = set_start_bits(code, start_bits,
910     (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
911     &compile_block) == SSB_DONE;
912     }
913    
914     /* Find the minimum length of subject string. */
915 nigel 77
916 ph10 455 min = find_minlength(code, code, re->options);
917 nigel 77
918 ph10 455 /* Return NULL if no optimization is possible. */
919 nigel 77
920 ph10 455 if (!bits_set && min < 0) return NULL;
921 nigel 77
922     /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
923     the latter, which is pointed to by the former, which may also get additional
924     data set later by the calling program. At the moment, the size of
925     pcre_study_data is fixed. We nevertheless save it in a field for returning via
926     the pcre_fullinfo() function so that if it becomes variable in the future, we
927     don't have to change that code. */
928    
929     extra = (pcre_extra *)(pcre_malloc)
930     (sizeof(pcre_extra) + sizeof(pcre_study_data));
931    
932     if (extra == NULL)
933     {
934     *errorptr = "failed to get memory";
935     return NULL;
936     }
937    
938     study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
939     extra->flags = PCRE_EXTRA_STUDY_DATA;
940     extra->study_data = study;
941    
942     study->size = sizeof(pcre_study_data);
943 ph10 455 study->flags = 0;
944 nigel 77
945 ph10 455 if (bits_set)
946     {
947     study->flags |= PCRE_STUDY_MAPPED;
948     memcpy(study->start_bits, start_bits, sizeof(start_bits));
949     }
950    
951     if (min >= 0)
952     {
953     study->flags |= PCRE_STUDY_MINLEN;
954     study->minlength = min;
955     }
956    
957 nigel 77 return extra;
958     }
959    
960     /* End of pcre_study.c */

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