/[pcre]/code/trunk/pcre_study.c
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Revision 538 - (hide annotations) (download)
Wed Jun 9 19:30:57 2010 UTC (4 years, 2 months ago) by ph10
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File size: 30436 byte(s)
Fix pcre_study() problem with non-C-locale chartables in UTF-8 mode.

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     enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE };
56    
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     code pointer to start of group (the bracket)
70     startcode pointer to start of the whole pattern
71 ph10 461 options the compiling options
72 ph10 455
73     Returns: the minimum length
74     -1 if \C was encountered
75 ph10 461 -2 internal error (missing capturing bracket)
76 ph10 455 */
77    
78     static int
79     find_minlength(const uschar *code, const uschar *startcode, int options)
80     {
81     int length = -1;
82     BOOL utf8 = (options & PCRE_UTF8) != 0;
83     BOOL had_recurse = FALSE;
84     register int branchlength = 0;
85     register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
86    
87     if (*code == OP_CBRA || *code == OP_SCBRA) cc += 2;
88    
89     /* Scan along the opcodes for this branch. If we get to the end of the
90     branch, check the length against that of the other branches. */
91    
92     for (;;)
93     {
94     int d, min;
95 ph10 461 uschar *cs, *ce;
96 ph10 455 register int op = *cc;
97 ph10 461
98 ph10 455 switch (op)
99     {
100 ph10 471 case OP_COND:
101     case OP_SCOND:
102    
103     /* If there is only one branch in a condition, the implied branch has zero
104     length, so we don't add anything. This covers the DEFINE "condition"
105     automatically. */
106    
107     cs = cc + GET(cc, 1);
108     if (*cs != OP_ALT)
109     {
110     cc = cs + 1 + LINK_SIZE;
111     break;
112     }
113    
114     /* Otherwise we can fall through and treat it the same as any other
115     subpattern. */
116    
117 ph10 455 case OP_CBRA:
118 ph10 461 case OP_SCBRA:
119 ph10 455 case OP_BRA:
120 ph10 461 case OP_SBRA:
121 ph10 455 case OP_ONCE:
122     d = find_minlength(cc, startcode, options);
123     if (d < 0) return d;
124     branchlength += d;
125     do cc += GET(cc, 1); while (*cc == OP_ALT);
126     cc += 1 + LINK_SIZE;
127     break;
128    
129     /* Reached end of a branch; if it's a ket it is the end of a nested
130     call. If it's ALT it is an alternation in a nested call. If it is
131     END it's the end of the outer call. All can be handled by the same code. */
132    
133     case OP_ALT:
134     case OP_KET:
135     case OP_KETRMAX:
136     case OP_KETRMIN:
137     case OP_END:
138 ph10 461 if (length < 0 || (!had_recurse && branchlength < length))
139 ph10 455 length = branchlength;
140     if (*cc != OP_ALT) return length;
141     cc += 1 + LINK_SIZE;
142     branchlength = 0;
143 ph10 461 had_recurse = FALSE;
144 ph10 455 break;
145    
146     /* Skip over assertive subpatterns */
147    
148     case OP_ASSERT:
149     case OP_ASSERT_NOT:
150     case OP_ASSERTBACK:
151     case OP_ASSERTBACK_NOT:
152     do cc += GET(cc, 1); while (*cc == OP_ALT);
153     /* Fall through */
154    
155     /* Skip over things that don't match chars */
156    
157     case OP_REVERSE:
158     case OP_CREF:
159 ph10 459 case OP_NCREF:
160 ph10 455 case OP_RREF:
161 ph10 459 case OP_NRREF:
162 ph10 455 case OP_DEF:
163     case OP_OPT:
164     case OP_CALLOUT:
165     case OP_SOD:
166     case OP_SOM:
167     case OP_EOD:
168     case OP_EODN:
169     case OP_CIRC:
170     case OP_DOLL:
171     case OP_NOT_WORD_BOUNDARY:
172     case OP_WORD_BOUNDARY:
173     cc += _pcre_OP_lengths[*cc];
174     break;
175 ph10 461
176 ph10 455 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
177    
178     case OP_BRAZERO:
179 ph10 461 case OP_BRAMINZERO:
180 ph10 455 case OP_SKIPZERO:
181     cc += _pcre_OP_lengths[*cc];
182     do cc += GET(cc, 1); while (*cc == OP_ALT);
183     cc += 1 + LINK_SIZE;
184     break;
185    
186     /* Handle literal characters and + repetitions */
187    
188     case OP_CHAR:
189     case OP_CHARNC:
190     case OP_NOT:
191     case OP_PLUS:
192     case OP_MINPLUS:
193     case OP_POSPLUS:
194     case OP_NOTPLUS:
195     case OP_NOTMINPLUS:
196     case OP_NOTPOSPLUS:
197     branchlength++;
198     cc += 2;
199     #ifdef SUPPORT_UTF8
200     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
201     #endif
202     break;
203 ph10 461
204 ph10 455 case OP_TYPEPLUS:
205     case OP_TYPEMINPLUS:
206 ph10 461 case OP_TYPEPOSPLUS:
207 ph10 455 branchlength++;
208     cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
209     break;
210    
211     /* Handle exact repetitions. The count is already in characters, but we
212     need to skip over a multibyte character in UTF8 mode. */
213    
214     case OP_EXACT:
215 ph10 461 case OP_NOTEXACT:
216 ph10 455 branchlength += GET2(cc,1);
217     cc += 4;
218     #ifdef SUPPORT_UTF8
219     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
220     #endif
221     break;
222    
223     case OP_TYPEEXACT:
224     branchlength += GET2(cc,1);
225     cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
226     break;
227    
228     /* Handle single-char non-literal matchers */
229    
230     case OP_PROP:
231     case OP_NOTPROP:
232     cc += 2;
233     /* Fall through */
234    
235     case OP_NOT_DIGIT:
236     case OP_DIGIT:
237     case OP_NOT_WHITESPACE:
238     case OP_WHITESPACE:
239     case OP_NOT_WORDCHAR:
240     case OP_WORDCHAR:
241     case OP_ANY:
242     case OP_ALLANY:
243     case OP_EXTUNI:
244 ph10 461 case OP_HSPACE:
245 ph10 455 case OP_NOT_HSPACE:
246     case OP_VSPACE:
247 ph10 461 case OP_NOT_VSPACE:
248 ph10 455 branchlength++;
249     cc++;
250     break;
251 ph10 461
252 ph10 455 /* "Any newline" might match two characters */
253 ph10 461
254 ph10 455 case OP_ANYNL:
255     branchlength += 2;
256     cc++;
257 ph10 461 break;
258 ph10 455
259     /* The single-byte matcher means we can't proceed in UTF-8 mode */
260    
261     case OP_ANYBYTE:
262     #ifdef SUPPORT_UTF8
263     if (utf8) return -1;
264     #endif
265     branchlength++;
266     cc++;
267 ph10 461 break;
268 ph10 455
269     /* For repeated character types, we have to test for \p and \P, which have
270     an extra two bytes of parameters. */
271    
272     case OP_TYPESTAR:
273     case OP_TYPEMINSTAR:
274     case OP_TYPEQUERY:
275     case OP_TYPEMINQUERY:
276     case OP_TYPEPOSSTAR:
277     case OP_TYPEPOSQUERY:
278     if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
279     cc += _pcre_OP_lengths[op];
280     break;
281    
282     case OP_TYPEUPTO:
283     case OP_TYPEMINUPTO:
284     case OP_TYPEPOSUPTO:
285     if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
286     cc += _pcre_OP_lengths[op];
287     break;
288    
289     /* Check a class for variable quantification */
290    
291     #ifdef SUPPORT_UTF8
292     case OP_XCLASS:
293     cc += GET(cc, 1) - 33;
294     /* Fall through */
295     #endif
296    
297     case OP_CLASS:
298     case OP_NCLASS:
299     cc += 33;
300    
301     switch (*cc)
302     {
303     case OP_CRPLUS:
304     case OP_CRMINPLUS:
305     branchlength++;
306 ph10 461 /* Fall through */
307 ph10 455
308     case OP_CRSTAR:
309     case OP_CRMINSTAR:
310     case OP_CRQUERY:
311     case OP_CRMINQUERY:
312 ph10 461 cc++;
313 ph10 455 break;
314 ph10 461
315 ph10 455 case OP_CRRANGE:
316     case OP_CRMINRANGE:
317     branchlength += GET2(cc,1);
318     cc += 5;
319     break;
320 ph10 461
321 ph10 455 default:
322     branchlength++;
323 ph10 461 break;
324 ph10 455 }
325     break;
326 ph10 461
327     /* Backreferences and subroutine calls are treated in the same way: we find
328     the minimum length for the subpattern. A recursion, however, causes an
329 ph10 455 a flag to be set that causes the length of this branch to be ignored. The
330     logic is that a recursion can only make sense if there is another
331     alternation that stops the recursing. That will provide the minimum length
332     (when no recursion happens). A backreference within the group that it is
333 ph10 469 referencing behaves in the same way.
334    
335 ph10 467 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
336     matches an empty string (by default it causes a matching failure), so in
337     that case we must set the minimum length to zero. */
338 ph10 461
339 ph10 455 case OP_REF:
340 ph10 467 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
341 ph10 469 {
342 ph10 467 ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
343     if (cs == NULL) return -2;
344     do ce += GET(ce, 1); while (*ce == OP_ALT);
345     if (cc > cs && cc < ce)
346     {
347     d = 0;
348     had_recurse = TRUE;
349     }
350     else d = find_minlength(cs, startcode, options);
351 ph10 461 }
352 ph10 469 else d = 0;
353 ph10 461 cc += 3;
354 ph10 455
355     /* Handle repeated back references */
356 ph10 461
357 ph10 455 switch (*cc)
358     {
359     case OP_CRSTAR:
360     case OP_CRMINSTAR:
361     case OP_CRQUERY:
362     case OP_CRMINQUERY:
363     min = 0;
364     cc++;
365     break;
366 ph10 461
367 ph10 455 case OP_CRRANGE:
368     case OP_CRMINRANGE:
369     min = GET2(cc, 1);
370     cc += 5;
371     break;
372 ph10 461
373 ph10 455 default:
374     min = 1;
375     break;
376     }
377    
378     branchlength += min * d;
379 ph10 461 break;
380 ph10 455
381 ph10 461 case OP_RECURSE:
382 ph10 455 cs = ce = (uschar *)startcode + GET(cc, 1);
383     if (cs == NULL) return -2;
384     do ce += GET(ce, 1); while (*ce == OP_ALT);
385     if (cc > cs && cc < ce)
386 ph10 461 had_recurse = TRUE;
387     else
388 ph10 455 branchlength += find_minlength(cs, startcode, options);
389     cc += 1 + LINK_SIZE;
390     break;
391    
392     /* Anything else does not or need not match a character. We can get the
393 ph10 461 item's length from the table, but for those that can match zero occurrences
394     of a character, we must take special action for UTF-8 characters. */
395    
396 ph10 455 case OP_UPTO:
397 ph10 461 case OP_NOTUPTO:
398 ph10 455 case OP_MINUPTO:
399 ph10 461 case OP_NOTMINUPTO:
400 ph10 455 case OP_POSUPTO:
401     case OP_STAR:
402     case OP_MINSTAR:
403 ph10 461 case OP_NOTMINSTAR:
404 ph10 455 case OP_POSSTAR:
405 ph10 461 case OP_NOTPOSSTAR:
406 ph10 455 case OP_QUERY:
407     case OP_MINQUERY:
408     case OP_NOTMINQUERY:
409     case OP_POSQUERY:
410 ph10 461 case OP_NOTPOSQUERY:
411 ph10 455 cc += _pcre_OP_lengths[op];
412 ph10 461 #ifdef SUPPORT_UTF8
413 ph10 455 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
414 ph10 461 #endif
415 ph10 455 break;
416 ph10 512
417 ph10 510 /* Skip these, but we need to add in the name length. */
418 ph10 512
419 ph10 510 case OP_MARK:
420     case OP_PRUNE_ARG:
421     case OP_SKIP_ARG:
422     case OP_THEN_ARG:
423     cc += _pcre_OP_lengths[op] + cc[1];
424 ph10 512 break;
425 ph10 455
426     /* For the record, these are the opcodes that are matched by "default":
427     OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
428     OP_THEN. */
429 ph10 461
430 ph10 455 default:
431     cc += _pcre_OP_lengths[op];
432     break;
433     }
434     }
435     /* Control never gets here */
436     }
437    
438    
439    
440     /*************************************************
441 nigel 77 * Set a bit and maybe its alternate case *
442     *************************************************/
443    
444 ph10 535 /* Given a character, set its first byte's bit in the table, and also the
445 ph10 520 corresponding bit for the other version of a letter if we are caseless. In
446     UTF-8 mode, for characters greater than 127, we can only do the caseless thing
447     when Unicode property support is available.
448 nigel 77
449     Arguments:
450     start_bits points to the bit map
451 ph10 520 p points to the character
452 nigel 77 caseless the caseless flag
453     cd the block with char table pointers
454 ph10 535 utf8 TRUE for UTF-8 mode
455 nigel 77
456 ph10 520 Returns: pointer after the character
457 nigel 77 */
458    
459 ph10 520 static const uschar *
460     set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
461     compile_data *cd, BOOL utf8)
462 nigel 77 {
463 ph10 520 unsigned int c = *p;
464    
465 ph10 524 SET_BIT(c);
466    
467 ph10 520 #ifdef SUPPORT_UTF8
468     if (utf8 && c > 127)
469     {
470     GETCHARINC(c, p);
471     #ifdef SUPPORT_UCP
472     if (caseless)
473     {
474 ph10 535 uschar buff[8];
475 ph10 520 c = UCD_OTHERCASE(c);
476 ph10 535 (void)_pcre_ord2utf8(c, buff);
477     SET_BIT(buff[0]);
478     }
479     #endif
480 ph10 520 return p;
481     }
482 ph10 535 #endif
483 ph10 520
484     /* Not UTF-8 mode, or character is less than 127. */
485    
486 ph10 524 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
487 ph10 520 return p + 1;
488 nigel 77 }
489    
490    
491    
492     /*************************************************
493 nigel 93 * Create bitmap of starting bytes *
494 nigel 77 *************************************************/
495    
496 nigel 93 /* This function scans a compiled unanchored expression recursively and
497     attempts to build a bitmap of the set of possible starting bytes. As time goes
498     by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
499     useful for parenthesized groups in patterns such as (a*)b where the group
500     provides some optional starting bytes but scanning must continue at the outer
501     level to find at least one mandatory byte. At the outermost level, this
502     function fails unless the result is SSB_DONE.
503 nigel 77
504     Arguments:
505     code points to an expression
506     start_bits points to a 32-byte table, initialized to 0
507     caseless the current state of the caseless flag
508     utf8 TRUE if in UTF-8 mode
509     cd the block with char table pointers
510    
511 nigel 93 Returns: SSB_FAIL => Failed to find any starting bytes
512     SSB_DONE => Found mandatory starting bytes
513     SSB_CONTINUE => Found optional starting bytes
514 nigel 77 */
515    
516 nigel 93 static int
517 nigel 77 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
518     BOOL utf8, compile_data *cd)
519     {
520     register int c;
521 nigel 93 int yield = SSB_DONE;
522 ph10 538 int table_limit = utf8? 16:32;
523 nigel 77
524 nigel 91 #if 0
525     /* ========================================================================= */
526     /* The following comment and code was inserted in January 1999. In May 2006,
527     when it was observed to cause compiler warnings about unused values, I took it
528     out again. If anybody is still using OS/2, they will have to put it back
529     manually. */
530    
531 nigel 77 /* This next statement and the later reference to dummy are here in order to
532     trick the optimizer of the IBM C compiler for OS/2 into generating correct
533     code. Apparently IBM isn't going to fix the problem, and we would rather not
534     disable optimization (in this module it actually makes a big difference, and
535     the pcre module can use all the optimization it can get). */
536    
537     volatile int dummy;
538 nigel 91 /* ========================================================================= */
539     #endif
540 nigel 77
541     do
542     {
543 nigel 93 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
544 nigel 77 BOOL try_next = TRUE;
545    
546 nigel 93 while (try_next) /* Loop for items in this branch */
547 nigel 77 {
548 nigel 93 int rc;
549     switch(*tcode)
550 nigel 77 {
551 nigel 93 /* Fail if we reach something we don't understand */
552 nigel 77
553     default:
554 nigel 93 return SSB_FAIL;
555 nigel 77
556 nigel 93 /* If we hit a bracket or a positive lookahead assertion, recurse to set
557     bits from within the subpattern. If it can't find anything, we have to
558     give up. If it finds some mandatory character(s), we are done for this
559     branch. Otherwise, carry on scanning after the subpattern. */
560    
561     case OP_BRA:
562     case OP_SBRA:
563     case OP_CBRA:
564     case OP_SCBRA:
565     case OP_ONCE:
566     case OP_ASSERT:
567     rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
568     if (rc == SSB_FAIL) return SSB_FAIL;
569     if (rc == SSB_DONE) try_next = FALSE; else
570     {
571     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
572     tcode += 1 + LINK_SIZE;
573     }
574     break;
575    
576     /* If we hit ALT or KET, it means we haven't found anything mandatory in
577     this branch, though we might have found something optional. For ALT, we
578     continue with the next alternative, but we have to arrange that the final
579     result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
580     return SSB_CONTINUE: if this is the top level, that indicates failure,
581     but after a nested subpattern, it causes scanning to continue. */
582    
583     case OP_ALT:
584     yield = SSB_CONTINUE;
585     try_next = FALSE;
586     break;
587    
588     case OP_KET:
589     case OP_KETRMAX:
590     case OP_KETRMIN:
591     return SSB_CONTINUE;
592    
593 nigel 77 /* Skip over callout */
594    
595     case OP_CALLOUT:
596     tcode += 2 + 2*LINK_SIZE;
597     break;
598    
599     /* Skip over lookbehind and negative lookahead assertions */
600    
601     case OP_ASSERT_NOT:
602     case OP_ASSERTBACK:
603     case OP_ASSERTBACK_NOT:
604     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
605 nigel 93 tcode += 1 + LINK_SIZE;
606 nigel 77 break;
607    
608     /* Skip over an option setting, changing the caseless flag */
609    
610     case OP_OPT:
611     caseless = (tcode[1] & PCRE_CASELESS) != 0;
612     tcode += 2;
613     break;
614    
615     /* BRAZERO does the bracket, but carries on. */
616    
617     case OP_BRAZERO:
618     case OP_BRAMINZERO:
619 nigel 93 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
620     return SSB_FAIL;
621 nigel 91 /* =========================================================================
622     See the comment at the head of this function concerning the next line,
623     which was an old fudge for the benefit of OS/2.
624 nigel 77 dummy = 1;
625 nigel 91 ========================================================================= */
626 nigel 77 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
627 nigel 93 tcode += 1 + LINK_SIZE;
628 nigel 77 break;
629    
630 ph10 335 /* SKIPZERO skips the bracket. */
631    
632     case OP_SKIPZERO:
633 ph10 358 tcode++;
634 ph10 335 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
635     tcode += 1 + LINK_SIZE;
636     break;
637    
638 nigel 77 /* Single-char * or ? sets the bit and tries the next item */
639    
640     case OP_STAR:
641     case OP_MINSTAR:
642 nigel 93 case OP_POSSTAR:
643 nigel 77 case OP_QUERY:
644     case OP_MINQUERY:
645 nigel 93 case OP_POSQUERY:
646 ph10 520 tcode = set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
647 nigel 77 break;
648    
649     /* Single-char upto sets the bit and tries the next */
650    
651     case OP_UPTO:
652     case OP_MINUPTO:
653 nigel 93 case OP_POSUPTO:
654 ph10 520 tcode = set_table_bit(start_bits, tcode + 3, caseless, cd, utf8);
655 nigel 77 break;
656    
657     /* At least one single char sets the bit and stops */
658    
659     case OP_EXACT: /* Fall through */
660     tcode += 2;
661    
662     case OP_CHAR:
663     case OP_CHARNC:
664     case OP_PLUS:
665     case OP_MINPLUS:
666 nigel 93 case OP_POSPLUS:
667 ph10 520 (void)set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
668 nigel 77 try_next = FALSE;
669     break;
670 ph10 535
671     /* Special spacing and line-terminating items. These recognize specific
672     lists of characters. The difference between VSPACE and ANYNL is that the
673     latter can match the two-character CRLF sequence, but that is not
674     relevant for finding the first character, so their code here is
675 ph10 524 identical. */
676 ph10 535
677 ph10 524 case OP_HSPACE:
678     SET_BIT(0x09);
679     SET_BIT(0x20);
680     if (utf8)
681 ph10 535 {
682 ph10 538 SET_BIT(0xC2); /* For U+00A0 */
683 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
684     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
685 ph10 535 SET_BIT(0xE3); /* For U+3000 */
686 ph10 524 }
687 ph10 538 else SET_BIT(0xA0);
688 ph10 524 try_next = FALSE;
689 ph10 535 break;
690 nigel 77
691 ph10 535 case OP_ANYNL:
692 ph10 524 case OP_VSPACE:
693 ph10 535 SET_BIT(0x0A);
694     SET_BIT(0x0B);
695     SET_BIT(0x0C);
696     SET_BIT(0x0D);
697 ph10 538 if (utf8)
698     {
699     SET_BIT(0xC2); /* For U+0085 */
700     SET_BIT(0xE2); /* For U+2028, U+2029 */
701     }
702     else SET_BIT(0x85);
703 ph10 524 try_next = FALSE;
704 ph10 535 break;
705 ph10 524
706 ph10 535 /* Single character types set the bits and stop. Note that if PCRE_UCP
707     is set, we do not see these op codes because \d etc are converted to
708     properties. Therefore, these apply in the case when only ASCII characters
709 ph10 538 are recognized to match the types. In UTF-8 mode, we must restrict
710     ourselves to bytes less than 128, as otherwise there can be confusion
711     with bytes in the middle of UTF-8 characters. (In a "traditional"
712     environment, the tables will only recognize ASCII characters anyway, but
713     in at least one Windows environment, some higher bytes bits were set in
714     the tables.) */
715 nigel 77
716     case OP_NOT_DIGIT:
717 ph10 538 for (c = 0; c < table_limit; c++)
718 nigel 77 start_bits[c] |= ~cd->cbits[c+cbit_digit];
719     try_next = FALSE;
720     break;
721    
722     case OP_DIGIT:
723 ph10 538 for (c = 0; c < table_limit; c++)
724 nigel 77 start_bits[c] |= cd->cbits[c+cbit_digit];
725     try_next = FALSE;
726     break;
727    
728 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
729     discard it. */
730    
731 nigel 77 case OP_NOT_WHITESPACE:
732 ph10 538 for (c = 0; c < table_limit; c++)
733 nigel 91 {
734     int d = cd->cbits[c+cbit_space];
735     if (c == 1) d &= ~0x08;
736     start_bits[c] |= ~d;
737     }
738 nigel 77 try_next = FALSE;
739     break;
740    
741 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
742     discard it. */
743    
744 nigel 77 case OP_WHITESPACE:
745 ph10 538 for (c = 0; c < table_limit; c++)
746 nigel 91 {
747     int d = cd->cbits[c+cbit_space];
748     if (c == 1) d &= ~0x08;
749     start_bits[c] |= d;
750     }
751 nigel 77 try_next = FALSE;
752     break;
753    
754     case OP_NOT_WORDCHAR:
755 ph10 538 for (c = 0; c < table_limit; c++)
756 nigel 77 start_bits[c] |= ~cd->cbits[c+cbit_word];
757     try_next = FALSE;
758     break;
759    
760     case OP_WORDCHAR:
761 ph10 538 for (c = 0; c < table_limit; c++)
762 nigel 77 start_bits[c] |= cd->cbits[c+cbit_word];
763     try_next = FALSE;
764     break;
765    
766     /* One or more character type fudges the pointer and restarts, knowing
767     it will hit a single character type and stop there. */
768    
769     case OP_TYPEPLUS:
770     case OP_TYPEMINPLUS:
771 ph10 535 case OP_TYPEPOSPLUS:
772 nigel 77 tcode++;
773     break;
774    
775     case OP_TYPEEXACT:
776     tcode += 3;
777     break;
778    
779     /* Zero or more repeats of character types set the bits and then
780     try again. */
781    
782     case OP_TYPEUPTO:
783     case OP_TYPEMINUPTO:
784 nigel 93 case OP_TYPEPOSUPTO:
785 nigel 77 tcode += 2; /* Fall through */
786    
787     case OP_TYPESTAR:
788     case OP_TYPEMINSTAR:
789 nigel 93 case OP_TYPEPOSSTAR:
790 nigel 77 case OP_TYPEQUERY:
791     case OP_TYPEMINQUERY:
792 nigel 93 case OP_TYPEPOSQUERY:
793 nigel 77 switch(tcode[1])
794     {
795 ph10 523 default:
796 nigel 77 case OP_ANY:
797 ph10 345 case OP_ALLANY:
798 nigel 93 return SSB_FAIL;
799 ph10 535
800 ph10 524 case OP_HSPACE:
801     SET_BIT(0x09);
802     SET_BIT(0x20);
803     if (utf8)
804 ph10 535 {
805 ph10 538 SET_BIT(0xC2); /* For U+00A0 */
806 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
807     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
808 ph10 535 SET_BIT(0xE3); /* For U+3000 */
809 ph10 524 }
810 ph10 538 else SET_BIT(0xA0);
811 ph10 535 break;
812    
813     case OP_ANYNL:
814 ph10 524 case OP_VSPACE:
815 ph10 535 SET_BIT(0x0A);
816     SET_BIT(0x0B);
817     SET_BIT(0x0C);
818     SET_BIT(0x0D);
819 ph10 538 if (utf8)
820     {
821     SET_BIT(0xC2); /* For U+0085 */
822     SET_BIT(0xE2); /* For U+2028, U+2029 */
823     }
824     else SET_BIT(0x85);
825 ph10 535 break;
826    
827 nigel 77 case OP_NOT_DIGIT:
828 ph10 538 for (c = 0; c < table_limit; c++)
829 nigel 77 start_bits[c] |= ~cd->cbits[c+cbit_digit];
830     break;
831    
832     case OP_DIGIT:
833 ph10 538 for (c = 0; c < table_limit; c++)
834 nigel 77 start_bits[c] |= cd->cbits[c+cbit_digit];
835     break;
836    
837 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
838     discard it. */
839    
840 nigel 77 case OP_NOT_WHITESPACE:
841 ph10 538 for (c = 0; c < table_limit; c++)
842 nigel 91 {
843     int d = cd->cbits[c+cbit_space];
844     if (c == 1) d &= ~0x08;
845     start_bits[c] |= ~d;
846     }
847 nigel 77 break;
848    
849 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
850     discard it. */
851    
852 nigel 77 case OP_WHITESPACE:
853 ph10 538 for (c = 0; c < table_limit; c++)
854 nigel 91 {
855     int d = cd->cbits[c+cbit_space];
856     if (c == 1) d &= ~0x08;
857     start_bits[c] |= d;
858     }
859 nigel 77 break;
860    
861     case OP_NOT_WORDCHAR:
862 ph10 538 for (c = 0; c < table_limit; c++)
863 nigel 77 start_bits[c] |= ~cd->cbits[c+cbit_word];
864     break;
865    
866     case OP_WORDCHAR:
867 ph10 538 for (c = 0; c < table_limit; c++)
868 nigel 77 start_bits[c] |= cd->cbits[c+cbit_word];
869     break;
870     }
871    
872     tcode += 2;
873     break;
874    
875     /* Character class where all the information is in a bit map: set the
876     bits and either carry on or not, according to the repeat count. If it was
877     a negative class, and we are operating with UTF-8 characters, any byte
878     with a value >= 0xc4 is a potentially valid starter because it starts a
879     character with a value > 255. */
880    
881     case OP_NCLASS:
882 ph10 111 #ifdef SUPPORT_UTF8
883 nigel 77 if (utf8)
884     {
885     start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
886     memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
887     }
888 ph10 111 #endif
889 nigel 77 /* Fall through */
890    
891     case OP_CLASS:
892     {
893     tcode++;
894    
895     /* In UTF-8 mode, the bits in a bit map correspond to character
896     values, not to byte values. However, the bit map we are constructing is
897     for byte values. So we have to do a conversion for characters whose
898     value is > 127. In fact, there are only two possible starting bytes for
899     characters in the range 128 - 255. */
900    
901 ph10 107 #ifdef SUPPORT_UTF8
902 nigel 77 if (utf8)
903     {
904     for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
905     for (c = 128; c < 256; c++)
906     {
907     if ((tcode[c/8] && (1 << (c&7))) != 0)
908     {
909     int d = (c >> 6) | 0xc0; /* Set bit for this starter */
910     start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
911     c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
912     }
913     }
914     }
915    
916     /* In non-UTF-8 mode, the two bit maps are completely compatible. */
917    
918     else
919 ph10 111 #endif
920 nigel 77 {
921     for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
922     }
923    
924     /* Advance past the bit map, and act on what follows */
925    
926     tcode += 32;
927     switch (*tcode)
928     {
929     case OP_CRSTAR:
930     case OP_CRMINSTAR:
931     case OP_CRQUERY:
932     case OP_CRMINQUERY:
933     tcode++;
934     break;
935    
936     case OP_CRRANGE:
937     case OP_CRMINRANGE:
938     if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
939     else try_next = FALSE;
940     break;
941    
942     default:
943     try_next = FALSE;
944     break;
945     }
946     }
947     break; /* End of bitmap class handling */
948    
949     } /* End of switch */
950     } /* End of try_next loop */
951    
952     code += GET(code, 1); /* Advance to next branch */
953     }
954     while (*code == OP_ALT);
955 nigel 93 return yield;
956 nigel 77 }
957    
958    
959    
960     /*************************************************
961     * Study a compiled expression *
962     *************************************************/
963    
964     /* This function is handed a compiled expression that it must study to produce
965     information that will speed up the matching. It returns a pcre_extra block
966     which then gets handed back to pcre_exec().
967    
968     Arguments:
969     re points to the compiled expression
970     options contains option bits
971     errorptr points to where to place error messages;
972     set NULL unless error
973    
974     Returns: pointer to a pcre_extra block, with study_data filled in and the
975 ph10 455 appropriate flags set;
976 nigel 77 NULL on error or if no optimization possible
977     */
978    
979 ph10 359 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
980 nigel 77 pcre_study(const pcre *external_re, int options, const char **errorptr)
981     {
982 ph10 455 int min;
983     BOOL bits_set = FALSE;
984 nigel 77 uschar start_bits[32];
985     pcre_extra *extra;
986     pcre_study_data *study;
987     const uschar *tables;
988 nigel 91 uschar *code;
989     compile_data compile_block;
990 nigel 77 const real_pcre *re = (const real_pcre *)external_re;
991    
992     *errorptr = NULL;
993    
994     if (re == NULL || re->magic_number != MAGIC_NUMBER)
995     {
996     *errorptr = "argument is not a compiled regular expression";
997     return NULL;
998     }
999    
1000     if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1001     {
1002     *errorptr = "unknown or incorrect option bit(s) set";
1003     return NULL;
1004     }
1005    
1006 nigel 91 code = (uschar *)re + re->name_table_offset +
1007     (re->name_count * re->name_entry_size);
1008    
1009 nigel 77 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1010 ph10 461 a multiline pattern that matches only at "line starts", there is no point in
1011 ph10 455 seeking a list of starting bytes. */
1012 nigel 77
1013 ph10 455 if ((re->options & PCRE_ANCHORED) == 0 &&
1014     (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1015     {
1016     /* Set the character tables in the block that is passed around */
1017 ph10 461
1018 ph10 455 tables = re->tables;
1019     if (tables == NULL)
1020     (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1021     (void *)(&tables));
1022 ph10 461
1023 ph10 455 compile_block.lcc = tables + lcc_offset;
1024     compile_block.fcc = tables + fcc_offset;
1025     compile_block.cbits = tables + cbits_offset;
1026     compile_block.ctypes = tables + ctypes_offset;
1027 ph10 461
1028 ph10 455 /* See if we can find a fixed set of initial characters for the pattern. */
1029 ph10 461
1030 ph10 455 memset(start_bits, 0, 32 * sizeof(uschar));
1031 ph10 461 bits_set = set_start_bits(code, start_bits,
1032     (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
1033 ph10 455 &compile_block) == SSB_DONE;
1034     }
1035 ph10 461
1036 ph10 455 /* Find the minimum length of subject string. */
1037 nigel 77
1038 ph10 455 min = find_minlength(code, code, re->options);
1039 nigel 77
1040 ph10 455 /* Return NULL if no optimization is possible. */
1041 nigel 77
1042 ph10 455 if (!bits_set && min < 0) return NULL;
1043 nigel 77
1044     /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
1045     the latter, which is pointed to by the former, which may also get additional
1046     data set later by the calling program. At the moment, the size of
1047     pcre_study_data is fixed. We nevertheless save it in a field for returning via
1048     the pcre_fullinfo() function so that if it becomes variable in the future, we
1049     don't have to change that code. */
1050    
1051     extra = (pcre_extra *)(pcre_malloc)
1052     (sizeof(pcre_extra) + sizeof(pcre_study_data));
1053    
1054     if (extra == NULL)
1055     {
1056     *errorptr = "failed to get memory";
1057     return NULL;
1058     }
1059    
1060     study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1061     extra->flags = PCRE_EXTRA_STUDY_DATA;
1062     extra->study_data = study;
1063    
1064     study->size = sizeof(pcre_study_data);
1065 ph10 455 study->flags = 0;
1066 nigel 77
1067 ph10 455 if (bits_set)
1068     {
1069     study->flags |= PCRE_STUDY_MAPPED;
1070     memcpy(study->start_bits, start_bits, sizeof(start_bits));
1071     }
1072 ph10 461
1073 ph10 455 if (min >= 0)
1074     {
1075     study->flags |= PCRE_STUDY_MINLEN;
1076     study->minlength = min;
1077 ph10 461 }
1078 ph10 455
1079 nigel 77 return extra;
1080     }
1081    
1082     /* End of pcre_study.c */

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