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Revision 550 - (hide annotations) (download)
Sun Oct 10 16:24:11 2010 UTC (3 years, 10 months ago) by ph10
File MIME type: text/plain
File size: 32236 byte(s)
Fix problem with (*THEN) not backing up far enough.

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     cc += _pcre_OP_lengths[op] + cc[1];
423 ph10 512 break;
424 ph10 455
425 ph10 550 case OP_THEN_ARG:
426     cc += _pcre_OP_lengths[op] + cc[1+LINK_SIZE];
427     break;
428    
429 ph10 455 /* For the record, these are the opcodes that are matched by "default":
430     OP_ACCEPT, OP_CLOSE, OP_COMMIT, OP_FAIL, OP_PRUNE, OP_SET_SOM, OP_SKIP,
431     OP_THEN. */
432 ph10 461
433 ph10 455 default:
434     cc += _pcre_OP_lengths[op];
435     break;
436     }
437     }
438     /* Control never gets here */
439     }
440    
441    
442    
443     /*************************************************
444 nigel 77 * Set a bit and maybe its alternate case *
445     *************************************************/
446    
447 ph10 535 /* Given a character, set its first byte's bit in the table, and also the
448 ph10 520 corresponding bit for the other version of a letter if we are caseless. In
449     UTF-8 mode, for characters greater than 127, we can only do the caseless thing
450     when Unicode property support is available.
451 nigel 77
452     Arguments:
453     start_bits points to the bit map
454 ph10 520 p points to the character
455 nigel 77 caseless the caseless flag
456     cd the block with char table pointers
457 ph10 535 utf8 TRUE for UTF-8 mode
458 nigel 77
459 ph10 520 Returns: pointer after the character
460 nigel 77 */
461    
462 ph10 520 static const uschar *
463     set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
464     compile_data *cd, BOOL utf8)
465 nigel 77 {
466 ph10 520 unsigned int c = *p;
467    
468 ph10 524 SET_BIT(c);
469    
470 ph10 520 #ifdef SUPPORT_UTF8
471     if (utf8 && c > 127)
472     {
473     GETCHARINC(c, p);
474     #ifdef SUPPORT_UCP
475     if (caseless)
476     {
477 ph10 535 uschar buff[8];
478 ph10 520 c = UCD_OTHERCASE(c);
479 ph10 535 (void)_pcre_ord2utf8(c, buff);
480     SET_BIT(buff[0]);
481     }
482     #endif
483 ph10 520 return p;
484     }
485 ph10 535 #endif
486 ph10 520
487     /* Not UTF-8 mode, or character is less than 127. */
488    
489 ph10 524 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
490 ph10 520 return p + 1;
491 nigel 77 }
492    
493    
494    
495     /*************************************************
496 ph10 539 * Set bits for a positive character type *
497     *************************************************/
498    
499     /* This function sets starting bits for a character type. In UTF-8 mode, we can
500     only do a direct setting for bytes less than 128, as otherwise there can be
501     confusion with bytes in the middle of UTF-8 characters. In a "traditional"
502     environment, the tables will only recognize ASCII characters anyway, but in at
503     least one Windows environment, some higher bytes bits were set in the tables.
504     So we deal with that case by considering the UTF-8 encoding.
505    
506     Arguments:
507     start_bits the starting bitmap
508     cbit type the type of character wanted
509     table_limit 32 for non-UTF-8; 16 for UTF-8
510 ph10 545 cd the block with char table pointers
511 ph10 539
512     Returns: nothing
513     */
514    
515     static void
516     set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
517     compile_data *cd)
518     {
519 ph10 545 register int c;
520 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
521     if (table_limit == 32) return;
522     for (c = 128; c < 256; c++)
523     {
524     if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
525     {
526     uschar buff[8];
527     (void)_pcre_ord2utf8(c, buff);
528 ph10 545 SET_BIT(buff[0]);
529     }
530     }
531 ph10 539 }
532    
533    
534     /*************************************************
535     * Set bits for a negative character type *
536     *************************************************/
537    
538     /* This function sets starting bits for a negative character type such as \D.
539     In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
540     otherwise there can be confusion with bytes in the middle of UTF-8 characters.
541 ph10 545 Unlike in the positive case, where we can set appropriate starting bits for
542 ph10 539 specific high-valued UTF-8 characters, in this case we have to set the bits for
543 ph10 545 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
544 ph10 539 0xc0 (192) for simplicity.
545    
546     Arguments:
547     start_bits the starting bitmap
548     cbit type the type of character wanted
549     table_limit 32 for non-UTF-8; 16 for UTF-8
550 ph10 545 cd the block with char table pointers
551 ph10 539
552     Returns: nothing
553     */
554    
555     static void
556     set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
557     compile_data *cd)
558     {
559 ph10 545 register int c;
560 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
561     if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
562     }
563    
564    
565    
566     /*************************************************
567 nigel 93 * Create bitmap of starting bytes *
568 nigel 77 *************************************************/
569    
570 nigel 93 /* This function scans a compiled unanchored expression recursively and
571     attempts to build a bitmap of the set of possible starting bytes. As time goes
572     by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
573     useful for parenthesized groups in patterns such as (a*)b where the group
574     provides some optional starting bytes but scanning must continue at the outer
575     level to find at least one mandatory byte. At the outermost level, this
576     function fails unless the result is SSB_DONE.
577 nigel 77
578     Arguments:
579     code points to an expression
580     start_bits points to a 32-byte table, initialized to 0
581     caseless the current state of the caseless flag
582     utf8 TRUE if in UTF-8 mode
583     cd the block with char table pointers
584    
585 nigel 93 Returns: SSB_FAIL => Failed to find any starting bytes
586     SSB_DONE => Found mandatory starting bytes
587     SSB_CONTINUE => Found optional starting bytes
588 nigel 77 */
589    
590 nigel 93 static int
591 nigel 77 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
592     BOOL utf8, compile_data *cd)
593     {
594     register int c;
595 nigel 93 int yield = SSB_DONE;
596 ph10 538 int table_limit = utf8? 16:32;
597 nigel 77
598 nigel 91 #if 0
599     /* ========================================================================= */
600     /* The following comment and code was inserted in January 1999. In May 2006,
601     when it was observed to cause compiler warnings about unused values, I took it
602     out again. If anybody is still using OS/2, they will have to put it back
603     manually. */
604    
605 nigel 77 /* This next statement and the later reference to dummy are here in order to
606     trick the optimizer of the IBM C compiler for OS/2 into generating correct
607     code. Apparently IBM isn't going to fix the problem, and we would rather not
608     disable optimization (in this module it actually makes a big difference, and
609     the pcre module can use all the optimization it can get). */
610    
611     volatile int dummy;
612 nigel 91 /* ========================================================================= */
613     #endif
614 nigel 77
615     do
616     {
617 nigel 93 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
618 nigel 77 BOOL try_next = TRUE;
619    
620 nigel 93 while (try_next) /* Loop for items in this branch */
621 nigel 77 {
622 nigel 93 int rc;
623     switch(*tcode)
624 nigel 77 {
625 nigel 93 /* Fail if we reach something we don't understand */
626 nigel 77
627     default:
628 nigel 93 return SSB_FAIL;
629 nigel 77
630 nigel 93 /* If we hit a bracket or a positive lookahead assertion, recurse to set
631     bits from within the subpattern. If it can't find anything, we have to
632     give up. If it finds some mandatory character(s), we are done for this
633     branch. Otherwise, carry on scanning after the subpattern. */
634    
635     case OP_BRA:
636     case OP_SBRA:
637     case OP_CBRA:
638     case OP_SCBRA:
639     case OP_ONCE:
640     case OP_ASSERT:
641     rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
642     if (rc == SSB_FAIL) return SSB_FAIL;
643     if (rc == SSB_DONE) try_next = FALSE; else
644     {
645     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
646     tcode += 1 + LINK_SIZE;
647     }
648     break;
649    
650     /* If we hit ALT or KET, it means we haven't found anything mandatory in
651     this branch, though we might have found something optional. For ALT, we
652     continue with the next alternative, but we have to arrange that the final
653     result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
654     return SSB_CONTINUE: if this is the top level, that indicates failure,
655     but after a nested subpattern, it causes scanning to continue. */
656    
657     case OP_ALT:
658     yield = SSB_CONTINUE;
659     try_next = FALSE;
660     break;
661    
662     case OP_KET:
663     case OP_KETRMAX:
664     case OP_KETRMIN:
665     return SSB_CONTINUE;
666    
667 nigel 77 /* Skip over callout */
668    
669     case OP_CALLOUT:
670     tcode += 2 + 2*LINK_SIZE;
671     break;
672    
673     /* Skip over lookbehind and negative lookahead assertions */
674    
675     case OP_ASSERT_NOT:
676     case OP_ASSERTBACK:
677     case OP_ASSERTBACK_NOT:
678     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
679 nigel 93 tcode += 1 + LINK_SIZE;
680 nigel 77 break;
681    
682     /* Skip over an option setting, changing the caseless flag */
683    
684     case OP_OPT:
685     caseless = (tcode[1] & PCRE_CASELESS) != 0;
686     tcode += 2;
687     break;
688    
689     /* BRAZERO does the bracket, but carries on. */
690    
691     case OP_BRAZERO:
692     case OP_BRAMINZERO:
693 nigel 93 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
694     return SSB_FAIL;
695 nigel 91 /* =========================================================================
696     See the comment at the head of this function concerning the next line,
697     which was an old fudge for the benefit of OS/2.
698 nigel 77 dummy = 1;
699 nigel 91 ========================================================================= */
700 nigel 77 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
701 nigel 93 tcode += 1 + LINK_SIZE;
702 nigel 77 break;
703    
704 ph10 335 /* SKIPZERO skips the bracket. */
705    
706     case OP_SKIPZERO:
707 ph10 358 tcode++;
708 ph10 335 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
709     tcode += 1 + LINK_SIZE;
710     break;
711    
712 nigel 77 /* Single-char * or ? sets the bit and tries the next item */
713    
714     case OP_STAR:
715     case OP_MINSTAR:
716 nigel 93 case OP_POSSTAR:
717 nigel 77 case OP_QUERY:
718     case OP_MINQUERY:
719 nigel 93 case OP_POSQUERY:
720 ph10 520 tcode = set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
721 nigel 77 break;
722    
723     /* Single-char upto sets the bit and tries the next */
724    
725     case OP_UPTO:
726     case OP_MINUPTO:
727 nigel 93 case OP_POSUPTO:
728 ph10 520 tcode = set_table_bit(start_bits, tcode + 3, caseless, cd, utf8);
729 nigel 77 break;
730    
731     /* At least one single char sets the bit and stops */
732    
733     case OP_EXACT: /* Fall through */
734     tcode += 2;
735    
736     case OP_CHAR:
737     case OP_CHARNC:
738     case OP_PLUS:
739     case OP_MINPLUS:
740 nigel 93 case OP_POSPLUS:
741 ph10 520 (void)set_table_bit(start_bits, tcode + 1, caseless, cd, utf8);
742 nigel 77 try_next = FALSE;
743     break;
744 ph10 535
745     /* Special spacing and line-terminating items. These recognize specific
746     lists of characters. The difference between VSPACE and ANYNL is that the
747     latter can match the two-character CRLF sequence, but that is not
748     relevant for finding the first character, so their code here is
749 ph10 524 identical. */
750 ph10 535
751 ph10 524 case OP_HSPACE:
752     SET_BIT(0x09);
753     SET_BIT(0x20);
754     if (utf8)
755 ph10 535 {
756 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
757 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
758     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
759 ph10 535 SET_BIT(0xE3); /* For U+3000 */
760 ph10 524 }
761 ph10 538 else SET_BIT(0xA0);
762 ph10 524 try_next = FALSE;
763 ph10 535 break;
764 nigel 77
765 ph10 535 case OP_ANYNL:
766 ph10 524 case OP_VSPACE:
767 ph10 535 SET_BIT(0x0A);
768     SET_BIT(0x0B);
769     SET_BIT(0x0C);
770     SET_BIT(0x0D);
771 ph10 545 if (utf8)
772     {
773     SET_BIT(0xC2); /* For U+0085 */
774 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
775 ph10 545 }
776 ph10 538 else SET_BIT(0x85);
777 ph10 524 try_next = FALSE;
778 ph10 535 break;
779 ph10 524
780 ph10 535 /* Single character types set the bits and stop. Note that if PCRE_UCP
781     is set, we do not see these op codes because \d etc are converted to
782 ph10 545 properties. Therefore, these apply in the case when only characters less
783 ph10 539 than 256 are recognized to match the types. */
784 nigel 77
785     case OP_NOT_DIGIT:
786 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
787 nigel 77 try_next = FALSE;
788     break;
789    
790     case OP_DIGIT:
791 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
792 nigel 77 try_next = FALSE;
793     break;
794    
795 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
796 ph10 539 ensure it is set as not whitespace. */
797 nigel 91
798 nigel 77 case OP_NOT_WHITESPACE:
799 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
800     start_bits[1] |= 0x08;
801 nigel 77 try_next = FALSE;
802     break;
803    
804 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
805 ph10 539 not set it from the table. */
806 nigel 91
807 nigel 77 case OP_WHITESPACE:
808 ph10 539 c = start_bits[1]; /* Save in case it was already set */
809     set_type_bits(start_bits, cbit_space, table_limit, cd);
810     start_bits[1] = (start_bits[1] & ~0x08) | c;
811 nigel 77 try_next = FALSE;
812     break;
813    
814     case OP_NOT_WORDCHAR:
815 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
816 nigel 77 try_next = FALSE;
817     break;
818    
819     case OP_WORDCHAR:
820 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
821 nigel 77 try_next = FALSE;
822     break;
823 ph10 545
824 nigel 77 /* One or more character type fudges the pointer and restarts, knowing
825     it will hit a single character type and stop there. */
826    
827     case OP_TYPEPLUS:
828     case OP_TYPEMINPLUS:
829 ph10 535 case OP_TYPEPOSPLUS:
830 nigel 77 tcode++;
831     break;
832    
833     case OP_TYPEEXACT:
834     tcode += 3;
835     break;
836    
837     /* Zero or more repeats of character types set the bits and then
838     try again. */
839    
840     case OP_TYPEUPTO:
841     case OP_TYPEMINUPTO:
842 nigel 93 case OP_TYPEPOSUPTO:
843 nigel 77 tcode += 2; /* Fall through */
844    
845     case OP_TYPESTAR:
846     case OP_TYPEMINSTAR:
847 nigel 93 case OP_TYPEPOSSTAR:
848 nigel 77 case OP_TYPEQUERY:
849     case OP_TYPEMINQUERY:
850 nigel 93 case OP_TYPEPOSQUERY:
851 nigel 77 switch(tcode[1])
852     {
853 ph10 523 default:
854 nigel 77 case OP_ANY:
855 ph10 345 case OP_ALLANY:
856 nigel 93 return SSB_FAIL;
857 ph10 535
858 ph10 524 case OP_HSPACE:
859     SET_BIT(0x09);
860     SET_BIT(0x20);
861     if (utf8)
862 ph10 535 {
863 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
864 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
865     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
866 ph10 535 SET_BIT(0xE3); /* For U+3000 */
867 ph10 524 }
868 ph10 538 else SET_BIT(0xA0);
869 ph10 535 break;
870    
871     case OP_ANYNL:
872 ph10 524 case OP_VSPACE:
873 ph10 535 SET_BIT(0x0A);
874     SET_BIT(0x0B);
875     SET_BIT(0x0C);
876     SET_BIT(0x0D);
877 ph10 545 if (utf8)
878 ph10 538 {
879 ph10 545 SET_BIT(0xC2); /* For U+0085 */
880 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
881 ph10 545 }
882 ph10 538 else SET_BIT(0x85);
883 ph10 535 break;
884    
885 nigel 77 case OP_NOT_DIGIT:
886 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
887 nigel 77 break;
888    
889     case OP_DIGIT:
890 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
891 nigel 77 break;
892    
893 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
894 ph10 539 ensure it gets set as not whitespace. */
895 nigel 91
896 nigel 77 case OP_NOT_WHITESPACE:
897 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
898 ph10 545 start_bits[1] |= 0x08;
899 nigel 77 break;
900    
901 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
902 ph10 539 avoid setting it. */
903 nigel 91
904 nigel 77 case OP_WHITESPACE:
905 ph10 539 c = start_bits[1]; /* Save in case it was already set */
906     set_type_bits(start_bits, cbit_space, table_limit, cd);
907     start_bits[1] = (start_bits[1] & ~0x08) | c;
908 nigel 77 break;
909    
910     case OP_NOT_WORDCHAR:
911 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
912 nigel 77 break;
913    
914     case OP_WORDCHAR:
915 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
916 nigel 77 break;
917     }
918    
919     tcode += 2;
920     break;
921    
922     /* Character class where all the information is in a bit map: set the
923     bits and either carry on or not, according to the repeat count. If it was
924     a negative class, and we are operating with UTF-8 characters, any byte
925     with a value >= 0xc4 is a potentially valid starter because it starts a
926     character with a value > 255. */
927    
928     case OP_NCLASS:
929 ph10 111 #ifdef SUPPORT_UTF8
930 nigel 77 if (utf8)
931     {
932     start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
933     memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
934     }
935 ph10 111 #endif
936 nigel 77 /* Fall through */
937    
938     case OP_CLASS:
939     {
940     tcode++;
941    
942     /* In UTF-8 mode, the bits in a bit map correspond to character
943     values, not to byte values. However, the bit map we are constructing is
944     for byte values. So we have to do a conversion for characters whose
945     value is > 127. In fact, there are only two possible starting bytes for
946     characters in the range 128 - 255. */
947    
948 ph10 107 #ifdef SUPPORT_UTF8
949 nigel 77 if (utf8)
950     {
951     for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
952     for (c = 128; c < 256; c++)
953     {
954     if ((tcode[c/8] && (1 << (c&7))) != 0)
955     {
956     int d = (c >> 6) | 0xc0; /* Set bit for this starter */
957     start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
958     c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
959     }
960     }
961     }
962    
963     /* In non-UTF-8 mode, the two bit maps are completely compatible. */
964    
965     else
966 ph10 111 #endif
967 nigel 77 {
968     for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
969     }
970    
971     /* Advance past the bit map, and act on what follows */
972    
973     tcode += 32;
974     switch (*tcode)
975     {
976     case OP_CRSTAR:
977     case OP_CRMINSTAR:
978     case OP_CRQUERY:
979     case OP_CRMINQUERY:
980     tcode++;
981     break;
982    
983     case OP_CRRANGE:
984     case OP_CRMINRANGE:
985     if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
986     else try_next = FALSE;
987     break;
988    
989     default:
990     try_next = FALSE;
991     break;
992     }
993     }
994     break; /* End of bitmap class handling */
995    
996     } /* End of switch */
997     } /* End of try_next loop */
998    
999     code += GET(code, 1); /* Advance to next branch */
1000     }
1001     while (*code == OP_ALT);
1002 nigel 93 return yield;
1003 nigel 77 }
1004    
1005    
1006    
1007     /*************************************************
1008     * Study a compiled expression *
1009     *************************************************/
1010    
1011     /* This function is handed a compiled expression that it must study to produce
1012     information that will speed up the matching. It returns a pcre_extra block
1013     which then gets handed back to pcre_exec().
1014    
1015     Arguments:
1016     re points to the compiled expression
1017     options contains option bits
1018     errorptr points to where to place error messages;
1019     set NULL unless error
1020    
1021     Returns: pointer to a pcre_extra block, with study_data filled in and the
1022 ph10 455 appropriate flags set;
1023 nigel 77 NULL on error or if no optimization possible
1024     */
1025    
1026 ph10 359 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1027 nigel 77 pcre_study(const pcre *external_re, int options, const char **errorptr)
1028     {
1029 ph10 455 int min;
1030     BOOL bits_set = FALSE;
1031 nigel 77 uschar start_bits[32];
1032     pcre_extra *extra;
1033     pcre_study_data *study;
1034     const uschar *tables;
1035 nigel 91 uschar *code;
1036     compile_data compile_block;
1037 nigel 77 const real_pcre *re = (const real_pcre *)external_re;
1038    
1039     *errorptr = NULL;
1040    
1041     if (re == NULL || re->magic_number != MAGIC_NUMBER)
1042     {
1043     *errorptr = "argument is not a compiled regular expression";
1044     return NULL;
1045     }
1046    
1047     if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1048     {
1049     *errorptr = "unknown or incorrect option bit(s) set";
1050     return NULL;
1051     }
1052    
1053 nigel 91 code = (uschar *)re + re->name_table_offset +
1054     (re->name_count * re->name_entry_size);
1055    
1056 nigel 77 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1057 ph10 461 a multiline pattern that matches only at "line starts", there is no point in
1058 ph10 455 seeking a list of starting bytes. */
1059 nigel 77
1060 ph10 455 if ((re->options & PCRE_ANCHORED) == 0 &&
1061     (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1062     {
1063     /* Set the character tables in the block that is passed around */
1064 ph10 461
1065 ph10 455 tables = re->tables;
1066     if (tables == NULL)
1067     (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1068     (void *)(&tables));
1069 ph10 461
1070 ph10 455 compile_block.lcc = tables + lcc_offset;
1071     compile_block.fcc = tables + fcc_offset;
1072     compile_block.cbits = tables + cbits_offset;
1073     compile_block.ctypes = tables + ctypes_offset;
1074 ph10 461
1075 ph10 455 /* See if we can find a fixed set of initial characters for the pattern. */
1076 ph10 461
1077 ph10 455 memset(start_bits, 0, 32 * sizeof(uschar));
1078 ph10 461 bits_set = set_start_bits(code, start_bits,
1079     (re->options & PCRE_CASELESS) != 0, (re->options & PCRE_UTF8) != 0,
1080 ph10 455 &compile_block) == SSB_DONE;
1081     }
1082 ph10 461
1083 ph10 455 /* Find the minimum length of subject string. */
1084 nigel 77
1085 ph10 455 min = find_minlength(code, code, re->options);
1086 nigel 77
1087 ph10 455 /* Return NULL if no optimization is possible. */
1088 nigel 77
1089 ph10 455 if (!bits_set && min < 0) return NULL;
1090 nigel 77
1091     /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
1092     the latter, which is pointed to by the former, which may also get additional
1093     data set later by the calling program. At the moment, the size of
1094     pcre_study_data is fixed. We nevertheless save it in a field for returning via
1095     the pcre_fullinfo() function so that if it becomes variable in the future, we
1096     don't have to change that code. */
1097    
1098     extra = (pcre_extra *)(pcre_malloc)
1099     (sizeof(pcre_extra) + sizeof(pcre_study_data));
1100    
1101     if (extra == NULL)
1102     {
1103     *errorptr = "failed to get memory";
1104     return NULL;
1105     }
1106    
1107     study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1108     extra->flags = PCRE_EXTRA_STUDY_DATA;
1109     extra->study_data = study;
1110    
1111     study->size = sizeof(pcre_study_data);
1112 ph10 455 study->flags = 0;
1113 nigel 77
1114 ph10 455 if (bits_set)
1115     {
1116     study->flags |= PCRE_STUDY_MAPPED;
1117     memcpy(study->start_bits, start_bits, sizeof(start_bits));
1118     }
1119 ph10 461
1120 ph10 455 if (min >= 0)
1121     {
1122     study->flags |= PCRE_STUDY_MINLEN;
1123     study->minlength = min;
1124 ph10 461 }
1125 ph10 455
1126 nigel 77 return extra;
1127     }
1128    
1129     /* End of pcre_study.c */

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