/[pcre]/code/trunk/pcre_study.c
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Revision 754 - (hide annotations) (download)
Sat Nov 19 18:32:18 2011 UTC (2 years, 8 months ago) by ph10
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File size: 38961 byte(s)
Support \C in lookbehinds and DFA matching when not 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 ph10 605 enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE, SSB_UNKNOWN };
56 nigel 93
57    
58 ph10 455
59 nigel 77 /*************************************************
60 ph10 455 * Find the minimum subject length for a group *
61     *************************************************/
62    
63     /* Scan a parenthesized group and compute the minimum length of subject that
64 ph10 461 is needed to match it. This is a lower bound; it does not mean there is a
65 ph10 455 string of that length that matches. In UTF8 mode, the result is in characters
66     rather than bytes.
67    
68     Arguments:
69 ph10 697 code pointer to start of group (the bracket)
70     startcode pointer to start of the whole pattern
71     options the compiling options
72     int RECURSE depth
73 ph10 455
74     Returns: the minimum length
75 ph10 697 -1 if \C in UTF-8 mode or (*ACCEPT) was encountered
76 ph10 461 -2 internal error (missing capturing bracket)
77 ph10 605 -3 internal error (opcode not listed)
78 ph10 455 */
79    
80     static int
81 ph10 612 find_minlength(const uschar *code, const uschar *startcode, int options,
82 ph10 697 int recurse_depth)
83 ph10 455 {
84     int length = -1;
85     BOOL utf8 = (options & PCRE_UTF8) != 0;
86     BOOL had_recurse = FALSE;
87     register int branchlength = 0;
88     register uschar *cc = (uschar *)code + 1 + LINK_SIZE;
89    
90 ph10 604 if (*code == OP_CBRA || *code == OP_SCBRA ||
91     *code == OP_CBRAPOS || *code == OP_SCBRAPOS) cc += 2;
92 ph10 455
93     /* Scan along the opcodes for this branch. If we get to the end of the
94     branch, check the length against that of the other branches. */
95    
96     for (;;)
97     {
98     int d, min;
99 ph10 461 uschar *cs, *ce;
100 ph10 455 register int op = *cc;
101 ph10 461
102 ph10 455 switch (op)
103     {
104 ph10 471 case OP_COND:
105     case OP_SCOND:
106    
107     /* If there is only one branch in a condition, the implied branch has zero
108     length, so we don't add anything. This covers the DEFINE "condition"
109     automatically. */
110    
111     cs = cc + GET(cc, 1);
112     if (*cs != OP_ALT)
113     {
114     cc = cs + 1 + LINK_SIZE;
115     break;
116     }
117    
118     /* Otherwise we can fall through and treat it the same as any other
119     subpattern. */
120    
121 ph10 455 case OP_CBRA:
122 ph10 461 case OP_SCBRA:
123 ph10 455 case OP_BRA:
124 ph10 461 case OP_SBRA:
125 ph10 604 case OP_CBRAPOS:
126     case OP_SCBRAPOS:
127     case OP_BRAPOS:
128     case OP_SBRAPOS:
129 ph10 455 case OP_ONCE:
130 ph10 723 case OP_ONCE_NC:
131 ph10 697 d = find_minlength(cc, startcode, options, recurse_depth);
132 ph10 455 if (d < 0) return d;
133     branchlength += d;
134     do cc += GET(cc, 1); while (*cc == OP_ALT);
135     cc += 1 + LINK_SIZE;
136     break;
137    
138 ph10 697 /* ACCEPT makes things far too complicated; we have to give up. */
139 ph10 455
140 ph10 654 case OP_ACCEPT:
141     case OP_ASSERT_ACCEPT:
142 ph10 708 return -1;
143 ph10 697
144     /* Reached end of a branch; if it's a ket it is the end of a nested
145     call. If it's ALT it is an alternation in a nested call. If it is END it's
146 ph10 708 the end of the outer call. All can be handled by the same code. If an
147     ACCEPT was previously encountered, use the length that was in force at that
148 ph10 697 time, and pass back the shortest ACCEPT length. */
149 ph10 708
150 ph10 455 case OP_ALT:
151     case OP_KET:
152     case OP_KETRMAX:
153     case OP_KETRMIN:
154 ph10 605 case OP_KETRPOS:
155 ph10 455 case OP_END:
156 ph10 461 if (length < 0 || (!had_recurse && branchlength < length))
157 ph10 455 length = branchlength;
158 ph10 612 if (op != OP_ALT) return length;
159 ph10 455 cc += 1 + LINK_SIZE;
160     branchlength = 0;
161 ph10 461 had_recurse = FALSE;
162 ph10 455 break;
163    
164     /* Skip over assertive subpatterns */
165    
166     case OP_ASSERT:
167     case OP_ASSERT_NOT:
168     case OP_ASSERTBACK:
169     case OP_ASSERTBACK_NOT:
170     do cc += GET(cc, 1); while (*cc == OP_ALT);
171     /* Fall through */
172    
173     /* Skip over things that don't match chars */
174    
175     case OP_REVERSE:
176     case OP_CREF:
177 ph10 459 case OP_NCREF:
178 ph10 455 case OP_RREF:
179 ph10 459 case OP_NRREF:
180 ph10 455 case OP_DEF:
181     case OP_CALLOUT:
182     case OP_SOD:
183     case OP_SOM:
184     case OP_EOD:
185     case OP_EODN:
186     case OP_CIRC:
187 ph10 602 case OP_CIRCM:
188 ph10 455 case OP_DOLL:
189 ph10 602 case OP_DOLLM:
190 ph10 455 case OP_NOT_WORD_BOUNDARY:
191     case OP_WORD_BOUNDARY:
192     cc += _pcre_OP_lengths[*cc];
193     break;
194 ph10 461
195 ph10 455 /* Skip over a subpattern that has a {0} or {0,x} quantifier */
196    
197     case OP_BRAZERO:
198 ph10 461 case OP_BRAMINZERO:
199 ph10 604 case OP_BRAPOSZERO:
200 ph10 455 case OP_SKIPZERO:
201     cc += _pcre_OP_lengths[*cc];
202     do cc += GET(cc, 1); while (*cc == OP_ALT);
203     cc += 1 + LINK_SIZE;
204     break;
205    
206     /* Handle literal characters and + repetitions */
207    
208     case OP_CHAR:
209 ph10 602 case OP_CHARI:
210 ph10 455 case OP_NOT:
211 ph10 602 case OP_NOTI:
212 ph10 455 case OP_PLUS:
213 ph10 603 case OP_PLUSI:
214 ph10 455 case OP_MINPLUS:
215 ph10 603 case OP_MINPLUSI:
216 ph10 455 case OP_POSPLUS:
217 ph10 603 case OP_POSPLUSI:
218 ph10 455 case OP_NOTPLUS:
219 ph10 603 case OP_NOTPLUSI:
220 ph10 455 case OP_NOTMINPLUS:
221 ph10 603 case OP_NOTMINPLUSI:
222 ph10 455 case OP_NOTPOSPLUS:
223 ph10 603 case OP_NOTPOSPLUSI:
224 ph10 455 branchlength++;
225     cc += 2;
226     #ifdef SUPPORT_UTF8
227     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
228     #endif
229     break;
230 ph10 461
231 ph10 455 case OP_TYPEPLUS:
232     case OP_TYPEMINPLUS:
233 ph10 461 case OP_TYPEPOSPLUS:
234 ph10 455 branchlength++;
235     cc += (cc[1] == OP_PROP || cc[1] == OP_NOTPROP)? 4 : 2;
236     break;
237    
238     /* Handle exact repetitions. The count is already in characters, but we
239     need to skip over a multibyte character in UTF8 mode. */
240    
241     case OP_EXACT:
242 ph10 603 case OP_EXACTI:
243 ph10 461 case OP_NOTEXACT:
244 ph10 603 case OP_NOTEXACTI:
245 ph10 455 branchlength += GET2(cc,1);
246     cc += 4;
247     #ifdef SUPPORT_UTF8
248     if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
249     #endif
250     break;
251    
252     case OP_TYPEEXACT:
253     branchlength += GET2(cc,1);
254     cc += (cc[3] == OP_PROP || cc[3] == OP_NOTPROP)? 6 : 4;
255     break;
256    
257     /* Handle single-char non-literal matchers */
258    
259     case OP_PROP:
260     case OP_NOTPROP:
261     cc += 2;
262     /* Fall through */
263    
264     case OP_NOT_DIGIT:
265     case OP_DIGIT:
266     case OP_NOT_WHITESPACE:
267     case OP_WHITESPACE:
268     case OP_NOT_WORDCHAR:
269     case OP_WORDCHAR:
270     case OP_ANY:
271     case OP_ALLANY:
272     case OP_EXTUNI:
273 ph10 461 case OP_HSPACE:
274 ph10 455 case OP_NOT_HSPACE:
275     case OP_VSPACE:
276 ph10 461 case OP_NOT_VSPACE:
277 ph10 455 branchlength++;
278     cc++;
279     break;
280 ph10 461
281 ph10 654 /* "Any newline" might match two characters, but it also might match just
282 ph10 611 one. */
283 ph10 461
284 ph10 455 case OP_ANYNL:
285 ph10 611 branchlength += 1;
286 ph10 455 cc++;
287 ph10 461 break;
288 ph10 455
289 ph10 754 /* The single-byte matcher means we can't proceed in UTF-8 mode. (In
290     non-UTF-8 mode \C will actually be turned into OP_ALLANY, so won't ever
291     appear, but leave the code, just in case.) */
292 ph10 455
293     case OP_ANYBYTE:
294     #ifdef SUPPORT_UTF8
295     if (utf8) return -1;
296     #endif
297     branchlength++;
298     cc++;
299 ph10 461 break;
300 ph10 455
301     /* For repeated character types, we have to test for \p and \P, which have
302     an extra two bytes of parameters. */
303    
304     case OP_TYPESTAR:
305     case OP_TYPEMINSTAR:
306     case OP_TYPEQUERY:
307     case OP_TYPEMINQUERY:
308     case OP_TYPEPOSSTAR:
309     case OP_TYPEPOSQUERY:
310     if (cc[1] == OP_PROP || cc[1] == OP_NOTPROP) cc += 2;
311     cc += _pcre_OP_lengths[op];
312     break;
313    
314     case OP_TYPEUPTO:
315     case OP_TYPEMINUPTO:
316     case OP_TYPEPOSUPTO:
317     if (cc[3] == OP_PROP || cc[3] == OP_NOTPROP) cc += 2;
318     cc += _pcre_OP_lengths[op];
319     break;
320    
321     /* Check a class for variable quantification */
322    
323     #ifdef SUPPORT_UTF8
324     case OP_XCLASS:
325     cc += GET(cc, 1) - 33;
326     /* Fall through */
327     #endif
328    
329     case OP_CLASS:
330     case OP_NCLASS:
331     cc += 33;
332    
333     switch (*cc)
334     {
335     case OP_CRPLUS:
336     case OP_CRMINPLUS:
337     branchlength++;
338 ph10 461 /* Fall through */
339 ph10 455
340     case OP_CRSTAR:
341     case OP_CRMINSTAR:
342     case OP_CRQUERY:
343     case OP_CRMINQUERY:
344 ph10 461 cc++;
345 ph10 455 break;
346 ph10 461
347 ph10 455 case OP_CRRANGE:
348     case OP_CRMINRANGE:
349     branchlength += GET2(cc,1);
350     cc += 5;
351     break;
352 ph10 461
353 ph10 455 default:
354     branchlength++;
355 ph10 461 break;
356 ph10 455 }
357     break;
358 ph10 461
359     /* Backreferences and subroutine calls are treated in the same way: we find
360     the minimum length for the subpattern. A recursion, however, causes an
361 ph10 455 a flag to be set that causes the length of this branch to be ignored. The
362     logic is that a recursion can only make sense if there is another
363     alternation that stops the recursing. That will provide the minimum length
364     (when no recursion happens). A backreference within the group that it is
365 ph10 469 referencing behaves in the same way.
366    
367 ph10 467 If PCRE_JAVASCRIPT_COMPAT is set, a backreference to an unset bracket
368     matches an empty string (by default it causes a matching failure), so in
369     that case we must set the minimum length to zero. */
370 ph10 461
371 ph10 455 case OP_REF:
372 ph10 602 case OP_REFI:
373 ph10 467 if ((options & PCRE_JAVASCRIPT_COMPAT) == 0)
374 ph10 469 {
375 ph10 467 ce = cs = (uschar *)_pcre_find_bracket(startcode, utf8, GET2(cc, 1));
376     if (cs == NULL) return -2;
377     do ce += GET(ce, 1); while (*ce == OP_ALT);
378     if (cc > cs && cc < ce)
379     {
380     d = 0;
381     had_recurse = TRUE;
382     }
383 ph10 654 else
384 ph10 612 {
385 ph10 697 d = find_minlength(cs, startcode, options, recurse_depth);
386 ph10 654 }
387 ph10 461 }
388 ph10 469 else d = 0;
389 ph10 461 cc += 3;
390 ph10 455
391     /* Handle repeated back references */
392 ph10 461
393 ph10 455 switch (*cc)
394     {
395     case OP_CRSTAR:
396     case OP_CRMINSTAR:
397     case OP_CRQUERY:
398     case OP_CRMINQUERY:
399     min = 0;
400     cc++;
401     break;
402 ph10 605
403     case OP_CRPLUS:
404     case OP_CRMINPLUS:
405     min = 1;
406     cc++;
407     break;
408    
409 ph10 455 case OP_CRRANGE:
410     case OP_CRMINRANGE:
411     min = GET2(cc, 1);
412     cc += 5;
413     break;
414 ph10 461
415 ph10 455 default:
416     min = 1;
417     break;
418     }
419    
420     branchlength += min * d;
421 ph10 461 break;
422 ph10 455
423 ph10 654 /* We can easily detect direct recursion, but not mutual recursion. This is
424     caught by a recursion depth count. */
425    
426 ph10 461 case OP_RECURSE:
427 ph10 455 cs = ce = (uschar *)startcode + GET(cc, 1);
428     do ce += GET(ce, 1); while (*ce == OP_ALT);
429 ph10 620 if ((cc > cs && cc < ce) || recurse_depth > 10)
430 ph10 461 had_recurse = TRUE;
431     else
432 ph10 654 {
433 ph10 697 branchlength += find_minlength(cs, startcode, options, recurse_depth + 1);
434 ph10 654 }
435 ph10 455 cc += 1 + LINK_SIZE;
436     break;
437    
438     /* Anything else does not or need not match a character. We can get the
439 ph10 461 item's length from the table, but for those that can match zero occurrences
440 ph10 602 of a character, we must take special action for UTF-8 characters. As it
441     happens, the "NOT" versions of these opcodes are used at present only for
442     ASCII characters, so they could be omitted from this list. However, in
443 ph10 605 future that may change, so we include them here so as not to leave a
444 ph10 603 gotcha for a future maintainer. */
445 ph10 461
446 ph10 455 case OP_UPTO:
447 ph10 602 case OP_UPTOI:
448 ph10 461 case OP_NOTUPTO:
449 ph10 602 case OP_NOTUPTOI:
450 ph10 455 case OP_MINUPTO:
451 ph10 602 case OP_MINUPTOI:
452 ph10 461 case OP_NOTMINUPTO:
453 ph10 602 case OP_NOTMINUPTOI:
454 ph10 455 case OP_POSUPTO:
455 ph10 602 case OP_POSUPTOI:
456     case OP_NOTPOSUPTO:
457     case OP_NOTPOSUPTOI:
458    
459 ph10 455 case OP_STAR:
460 ph10 602 case OP_STARI:
461     case OP_NOTSTAR:
462     case OP_NOTSTARI:
463 ph10 455 case OP_MINSTAR:
464 ph10 602 case OP_MINSTARI:
465 ph10 461 case OP_NOTMINSTAR:
466 ph10 602 case OP_NOTMINSTARI:
467 ph10 455 case OP_POSSTAR:
468 ph10 602 case OP_POSSTARI:
469 ph10 461 case OP_NOTPOSSTAR:
470 ph10 602 case OP_NOTPOSSTARI:
471    
472 ph10 455 case OP_QUERY:
473 ph10 602 case OP_QUERYI:
474     case OP_NOTQUERY:
475     case OP_NOTQUERYI:
476 ph10 455 case OP_MINQUERY:
477 ph10 602 case OP_MINQUERYI:
478 ph10 455 case OP_NOTMINQUERY:
479 ph10 602 case OP_NOTMINQUERYI:
480 ph10 455 case OP_POSQUERY:
481 ph10 602 case OP_POSQUERYI:
482 ph10 461 case OP_NOTPOSQUERY:
483 ph10 602 case OP_NOTPOSQUERYI:
484    
485 ph10 455 cc += _pcre_OP_lengths[op];
486 ph10 461 #ifdef SUPPORT_UTF8
487 ph10 455 if (utf8 && cc[-1] >= 0xc0) cc += _pcre_utf8_table4[cc[-1] & 0x3f];
488 ph10 461 #endif
489 ph10 455 break;
490 ph10 512
491 ph10 510 /* Skip these, but we need to add in the name length. */
492 ph10 512
493 ph10 510 case OP_MARK:
494     case OP_PRUNE_ARG:
495     case OP_SKIP_ARG:
496 ph10 729 case OP_THEN_ARG:
497 ph10 510 cc += _pcre_OP_lengths[op] + cc[1];
498 ph10 512 break;
499 ph10 455
500 ph10 603 /* The remaining opcodes are just skipped over. */
501 ph10 461
502 ph10 603 case OP_CLOSE:
503     case OP_COMMIT:
504     case OP_FAIL:
505     case OP_PRUNE:
506     case OP_SET_SOM:
507     case OP_SKIP:
508 ph10 605 case OP_THEN:
509 ph10 455 cc += _pcre_OP_lengths[op];
510     break;
511 ph10 605
512 ph10 603 /* This should not occur: we list all opcodes explicitly so that when
513     new ones get added they are properly considered. */
514    
515     default:
516     return -3;
517 ph10 455 }
518     }
519     /* Control never gets here */
520     }
521    
522    
523    
524     /*************************************************
525 nigel 77 * Set a bit and maybe its alternate case *
526     *************************************************/
527    
528 ph10 535 /* Given a character, set its first byte's bit in the table, and also the
529 ph10 520 corresponding bit for the other version of a letter if we are caseless. In
530     UTF-8 mode, for characters greater than 127, we can only do the caseless thing
531     when Unicode property support is available.
532 nigel 77
533     Arguments:
534     start_bits points to the bit map
535 ph10 520 p points to the character
536 nigel 77 caseless the caseless flag
537     cd the block with char table pointers
538 ph10 535 utf8 TRUE for UTF-8 mode
539 nigel 77
540 ph10 520 Returns: pointer after the character
541 nigel 77 */
542    
543 ph10 520 static const uschar *
544     set_table_bit(uschar *start_bits, const uschar *p, BOOL caseless,
545     compile_data *cd, BOOL utf8)
546 nigel 77 {
547 ph10 520 unsigned int c = *p;
548    
549 ph10 524 SET_BIT(c);
550    
551 ph10 520 #ifdef SUPPORT_UTF8
552     if (utf8 && c > 127)
553     {
554     GETCHARINC(c, p);
555     #ifdef SUPPORT_UCP
556     if (caseless)
557     {
558 ph10 535 uschar buff[8];
559 ph10 520 c = UCD_OTHERCASE(c);
560 ph10 535 (void)_pcre_ord2utf8(c, buff);
561     SET_BIT(buff[0]);
562     }
563     #endif
564 ph10 520 return p;
565     }
566 ph10 535 #endif
567 ph10 520
568     /* Not UTF-8 mode, or character is less than 127. */
569    
570 ph10 524 if (caseless && (cd->ctypes[c] & ctype_letter) != 0) SET_BIT(cd->fcc[c]);
571 ph10 520 return p + 1;
572 nigel 77 }
573    
574    
575    
576     /*************************************************
577 ph10 539 * Set bits for a positive character type *
578     *************************************************/
579    
580     /* This function sets starting bits for a character type. In UTF-8 mode, we can
581     only do a direct setting for bytes less than 128, as otherwise there can be
582     confusion with bytes in the middle of UTF-8 characters. In a "traditional"
583     environment, the tables will only recognize ASCII characters anyway, but in at
584     least one Windows environment, some higher bytes bits were set in the tables.
585     So we deal with that case by considering the UTF-8 encoding.
586    
587     Arguments:
588     start_bits the starting bitmap
589     cbit type the type of character wanted
590     table_limit 32 for non-UTF-8; 16 for UTF-8
591 ph10 545 cd the block with char table pointers
592 ph10 539
593     Returns: nothing
594     */
595    
596     static void
597     set_type_bits(uschar *start_bits, int cbit_type, int table_limit,
598     compile_data *cd)
599     {
600 ph10 545 register int c;
601 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= cd->cbits[c+cbit_type];
602     if (table_limit == 32) return;
603     for (c = 128; c < 256; c++)
604     {
605     if ((cd->cbits[c/8] & (1 << (c&7))) != 0)
606     {
607     uschar buff[8];
608     (void)_pcre_ord2utf8(c, buff);
609 ph10 545 SET_BIT(buff[0]);
610     }
611     }
612 ph10 539 }
613    
614    
615     /*************************************************
616     * Set bits for a negative character type *
617     *************************************************/
618    
619     /* This function sets starting bits for a negative character type such as \D.
620     In UTF-8 mode, we can only do a direct setting for bytes less than 128, as
621     otherwise there can be confusion with bytes in the middle of UTF-8 characters.
622 ph10 545 Unlike in the positive case, where we can set appropriate starting bits for
623 ph10 539 specific high-valued UTF-8 characters, in this case we have to set the bits for
624 ph10 545 all high-valued characters. The lowest is 0xc2, but we overkill by starting at
625 ph10 539 0xc0 (192) for simplicity.
626    
627     Arguments:
628     start_bits the starting bitmap
629     cbit type the type of character wanted
630     table_limit 32 for non-UTF-8; 16 for UTF-8
631 ph10 545 cd the block with char table pointers
632 ph10 539
633     Returns: nothing
634     */
635    
636     static void
637     set_nottype_bits(uschar *start_bits, int cbit_type, int table_limit,
638     compile_data *cd)
639     {
640 ph10 545 register int c;
641 ph10 539 for (c = 0; c < table_limit; c++) start_bits[c] |= ~cd->cbits[c+cbit_type];
642     if (table_limit != 32) for (c = 24; c < 32; c++) start_bits[c] = 0xff;
643     }
644    
645    
646    
647     /*************************************************
648 nigel 93 * Create bitmap of starting bytes *
649 nigel 77 *************************************************/
650    
651 nigel 93 /* This function scans a compiled unanchored expression recursively and
652     attempts to build a bitmap of the set of possible starting bytes. As time goes
653     by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
654     useful for parenthesized groups in patterns such as (a*)b where the group
655     provides some optional starting bytes but scanning must continue at the outer
656     level to find at least one mandatory byte. At the outermost level, this
657     function fails unless the result is SSB_DONE.
658 nigel 77
659     Arguments:
660     code points to an expression
661     start_bits points to a 32-byte table, initialized to 0
662     utf8 TRUE if in UTF-8 mode
663     cd the block with char table pointers
664    
665 nigel 93 Returns: SSB_FAIL => Failed to find any starting bytes
666     SSB_DONE => Found mandatory starting bytes
667     SSB_CONTINUE => Found optional starting bytes
668 ph10 605 SSB_UNKNOWN => Hit an unrecognized opcode
669 nigel 77 */
670    
671 nigel 93 static int
672 ph10 605 set_start_bits(const uschar *code, uschar *start_bits, BOOL utf8,
673 ph10 603 compile_data *cd)
674 nigel 77 {
675     register int c;
676 nigel 93 int yield = SSB_DONE;
677 ph10 538 int table_limit = utf8? 16:32;
678 nigel 77
679 nigel 91 #if 0
680     /* ========================================================================= */
681     /* The following comment and code was inserted in January 1999. In May 2006,
682     when it was observed to cause compiler warnings about unused values, I took it
683     out again. If anybody is still using OS/2, they will have to put it back
684     manually. */
685    
686 nigel 77 /* This next statement and the later reference to dummy are here in order to
687     trick the optimizer of the IBM C compiler for OS/2 into generating correct
688     code. Apparently IBM isn't going to fix the problem, and we would rather not
689     disable optimization (in this module it actually makes a big difference, and
690     the pcre module can use all the optimization it can get). */
691    
692     volatile int dummy;
693 nigel 91 /* ========================================================================= */
694     #endif
695 nigel 77
696     do
697     {
698     BOOL try_next = TRUE;
699 ph10 604 const uschar *tcode = code + 1 + LINK_SIZE;
700 ph10 605
701 ph10 604 if (*code == OP_CBRA || *code == OP_SCBRA ||
702     *code == OP_CBRAPOS || *code == OP_SCBRAPOS) tcode += 2;
703 nigel 77
704 nigel 93 while (try_next) /* Loop for items in this branch */
705 nigel 77 {
706 nigel 93 int rc;
707 ph10 612
708 nigel 93 switch(*tcode)
709 nigel 77 {
710 ph10 605 /* If we reach something we don't understand, it means a new opcode has
711     been created that hasn't been added to this code. Hopefully this problem
712     will be discovered during testing. */
713 nigel 77
714     default:
715 ph10 605 return SSB_UNKNOWN;
716    
717     /* Fail for a valid opcode that implies no starting bits. */
718    
719     case OP_ACCEPT:
720 ph10 654 case OP_ASSERT_ACCEPT:
721 ph10 605 case OP_ALLANY:
722     case OP_ANY:
723     case OP_ANYBYTE:
724     case OP_CIRC:
725 ph10 654 case OP_CIRCM:
726 ph10 605 case OP_CLOSE:
727     case OP_COMMIT:
728     case OP_COND:
729 ph10 654 case OP_CREF:
730 ph10 605 case OP_DEF:
731     case OP_DOLL:
732 ph10 654 case OP_DOLLM:
733 ph10 605 case OP_END:
734     case OP_EOD:
735 ph10 654 case OP_EODN:
736 ph10 605 case OP_EXTUNI:
737     case OP_FAIL:
738     case OP_MARK:
739     case OP_NCREF:
740     case OP_NOT:
741     case OP_NOTEXACT:
742     case OP_NOTEXACTI:
743 ph10 654 case OP_NOTI:
744 ph10 605 case OP_NOTMINPLUS:
745     case OP_NOTMINPLUSI:
746     case OP_NOTMINQUERY:
747     case OP_NOTMINQUERYI:
748     case OP_NOTMINSTAR:
749     case OP_NOTMINSTARI:
750     case OP_NOTMINUPTO:
751     case OP_NOTMINUPTOI:
752     case OP_NOTPLUS:
753     case OP_NOTPLUSI:
754     case OP_NOTPOSPLUS:
755     case OP_NOTPOSPLUSI:
756     case OP_NOTPOSQUERY:
757     case OP_NOTPOSQUERYI:
758     case OP_NOTPOSSTAR:
759     case OP_NOTPOSSTARI:
760     case OP_NOTPOSUPTO:
761     case OP_NOTPOSUPTOI:
762     case OP_NOTPROP:
763     case OP_NOTQUERY:
764     case OP_NOTQUERYI:
765     case OP_NOTSTAR:
766     case OP_NOTSTARI:
767     case OP_NOTUPTO:
768     case OP_NOTUPTOI:
769     case OP_NOT_HSPACE:
770     case OP_NOT_VSPACE:
771     case OP_NRREF:
772     case OP_PROP:
773     case OP_PRUNE:
774     case OP_PRUNE_ARG:
775     case OP_RECURSE:
776     case OP_REF:
777     case OP_REFI:
778     case OP_REVERSE:
779     case OP_RREF:
780 ph10 654 case OP_SCOND:
781 ph10 605 case OP_SET_SOM:
782     case OP_SKIP:
783     case OP_SKIP_ARG:
784     case OP_SOD:
785     case OP_SOM:
786     case OP_THEN:
787     case OP_THEN_ARG:
788     case OP_XCLASS:
789 nigel 93 return SSB_FAIL;
790 nigel 77
791 ph10 657 /* We can ignore word boundary tests. */
792 ph10 659
793 ph10 657 case OP_WORD_BOUNDARY:
794     case OP_NOT_WORD_BOUNDARY:
795 ph10 659 tcode++;
796     break;
797 ph10 657
798 nigel 93 /* If we hit a bracket or a positive lookahead assertion, recurse to set
799     bits from within the subpattern. If it can't find anything, we have to
800     give up. If it finds some mandatory character(s), we are done for this
801     branch. Otherwise, carry on scanning after the subpattern. */
802    
803     case OP_BRA:
804     case OP_SBRA:
805     case OP_CBRA:
806     case OP_SCBRA:
807 ph10 604 case OP_BRAPOS:
808     case OP_SBRAPOS:
809     case OP_CBRAPOS:
810     case OP_SCBRAPOS:
811 nigel 93 case OP_ONCE:
812 ph10 723 case OP_ONCE_NC:
813 nigel 93 case OP_ASSERT:
814 ph10 603 rc = set_start_bits(tcode, start_bits, utf8, cd);
815 ph10 605 if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
816 nigel 93 if (rc == SSB_DONE) try_next = FALSE; else
817     {
818     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
819     tcode += 1 + LINK_SIZE;
820     }
821     break;
822    
823     /* If we hit ALT or KET, it means we haven't found anything mandatory in
824     this branch, though we might have found something optional. For ALT, we
825     continue with the next alternative, but we have to arrange that the final
826     result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
827     return SSB_CONTINUE: if this is the top level, that indicates failure,
828     but after a nested subpattern, it causes scanning to continue. */
829    
830     case OP_ALT:
831     yield = SSB_CONTINUE;
832     try_next = FALSE;
833     break;
834    
835     case OP_KET:
836     case OP_KETRMAX:
837     case OP_KETRMIN:
838 ph10 605 case OP_KETRPOS:
839 nigel 93 return SSB_CONTINUE;
840    
841 nigel 77 /* Skip over callout */
842    
843     case OP_CALLOUT:
844     tcode += 2 + 2*LINK_SIZE;
845     break;
846    
847     /* Skip over lookbehind and negative lookahead assertions */
848    
849     case OP_ASSERT_NOT:
850     case OP_ASSERTBACK:
851     case OP_ASSERTBACK_NOT:
852     do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
853 nigel 93 tcode += 1 + LINK_SIZE;
854 nigel 77 break;
855    
856     /* BRAZERO does the bracket, but carries on. */
857    
858     case OP_BRAZERO:
859     case OP_BRAMINZERO:
860 ph10 604 case OP_BRAPOSZERO:
861 ph10 605 rc = set_start_bits(++tcode, start_bits, utf8, cd);
862     if (rc == SSB_FAIL || rc == SSB_UNKNOWN) return rc;
863 nigel 91 /* =========================================================================
864     See the comment at the head of this function concerning the next line,
865     which was an old fudge for the benefit of OS/2.
866 nigel 77 dummy = 1;
867 nigel 91 ========================================================================= */
868 nigel 77 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
869 nigel 93 tcode += 1 + LINK_SIZE;
870 nigel 77 break;
871    
872 ph10 335 /* SKIPZERO skips the bracket. */
873    
874     case OP_SKIPZERO:
875 ph10 358 tcode++;
876 ph10 335 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
877     tcode += 1 + LINK_SIZE;
878     break;
879    
880 nigel 77 /* Single-char * or ? sets the bit and tries the next item */
881    
882     case OP_STAR:
883     case OP_MINSTAR:
884 nigel 93 case OP_POSSTAR:
885 nigel 77 case OP_QUERY:
886     case OP_MINQUERY:
887 nigel 93 case OP_POSQUERY:
888 ph10 603 tcode = set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
889 nigel 77 break;
890    
891 ph10 602 case OP_STARI:
892     case OP_MINSTARI:
893     case OP_POSSTARI:
894     case OP_QUERYI:
895     case OP_MINQUERYI:
896     case OP_POSQUERYI:
897     tcode = set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
898     break;
899    
900 nigel 77 /* Single-char upto sets the bit and tries the next */
901    
902     case OP_UPTO:
903     case OP_MINUPTO:
904 nigel 93 case OP_POSUPTO:
905 ph10 603 tcode = set_table_bit(start_bits, tcode + 3, FALSE, cd, utf8);
906 nigel 77 break;
907    
908 ph10 602 case OP_UPTOI:
909     case OP_MINUPTOI:
910     case OP_POSUPTOI:
911     tcode = set_table_bit(start_bits, tcode + 3, TRUE, cd, utf8);
912     break;
913    
914 nigel 77 /* At least one single char sets the bit and stops */
915    
916 ph10 602 case OP_EXACT:
917 nigel 77 tcode += 2;
918 ph10 602 /* Fall through */
919 nigel 77 case OP_CHAR:
920     case OP_PLUS:
921     case OP_MINPLUS:
922 nigel 93 case OP_POSPLUS:
923 ph10 603 (void)set_table_bit(start_bits, tcode + 1, FALSE, cd, utf8);
924 nigel 77 try_next = FALSE;
925     break;
926 ph10 535
927 ph10 603 case OP_EXACTI:
928     tcode += 2;
929     /* Fall through */
930 ph10 602 case OP_CHARI:
931     case OP_PLUSI:
932     case OP_MINPLUSI:
933     case OP_POSPLUSI:
934     (void)set_table_bit(start_bits, tcode + 1, TRUE, cd, utf8);
935     try_next = FALSE;
936     break;
937    
938 ph10 535 /* Special spacing and line-terminating items. These recognize specific
939     lists of characters. The difference between VSPACE and ANYNL is that the
940     latter can match the two-character CRLF sequence, but that is not
941     relevant for finding the first character, so their code here is
942 ph10 524 identical. */
943 ph10 535
944 ph10 524 case OP_HSPACE:
945     SET_BIT(0x09);
946     SET_BIT(0x20);
947     if (utf8)
948 ph10 535 {
949 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
950 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
951     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
952 ph10 535 SET_BIT(0xE3); /* For U+3000 */
953 ph10 524 }
954 ph10 538 else SET_BIT(0xA0);
955 ph10 524 try_next = FALSE;
956 ph10 535 break;
957 nigel 77
958 ph10 535 case OP_ANYNL:
959 ph10 524 case OP_VSPACE:
960 ph10 535 SET_BIT(0x0A);
961     SET_BIT(0x0B);
962     SET_BIT(0x0C);
963     SET_BIT(0x0D);
964 ph10 545 if (utf8)
965     {
966     SET_BIT(0xC2); /* For U+0085 */
967 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
968 ph10 545 }
969 ph10 538 else SET_BIT(0x85);
970 ph10 524 try_next = FALSE;
971 ph10 535 break;
972 ph10 524
973 ph10 535 /* Single character types set the bits and stop. Note that if PCRE_UCP
974     is set, we do not see these op codes because \d etc are converted to
975 ph10 545 properties. Therefore, these apply in the case when only characters less
976 ph10 539 than 256 are recognized to match the types. */
977 nigel 77
978     case OP_NOT_DIGIT:
979 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
980 nigel 77 try_next = FALSE;
981     break;
982    
983     case OP_DIGIT:
984 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
985 nigel 77 try_next = FALSE;
986     break;
987    
988 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
989 ph10 539 ensure it is set as not whitespace. */
990 nigel 91
991 nigel 77 case OP_NOT_WHITESPACE:
992 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
993     start_bits[1] |= 0x08;
994 nigel 77 try_next = FALSE;
995     break;
996    
997 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
998 ph10 539 not set it from the table. */
999 nigel 91
1000 nigel 77 case OP_WHITESPACE:
1001 ph10 539 c = start_bits[1]; /* Save in case it was already set */
1002     set_type_bits(start_bits, cbit_space, table_limit, cd);
1003     start_bits[1] = (start_bits[1] & ~0x08) | c;
1004 nigel 77 try_next = FALSE;
1005     break;
1006    
1007     case OP_NOT_WORDCHAR:
1008 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1009 nigel 77 try_next = FALSE;
1010     break;
1011    
1012     case OP_WORDCHAR:
1013 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
1014 nigel 77 try_next = FALSE;
1015     break;
1016 ph10 545
1017 nigel 77 /* One or more character type fudges the pointer and restarts, knowing
1018     it will hit a single character type and stop there. */
1019    
1020     case OP_TYPEPLUS:
1021     case OP_TYPEMINPLUS:
1022 ph10 535 case OP_TYPEPOSPLUS:
1023 nigel 77 tcode++;
1024     break;
1025    
1026     case OP_TYPEEXACT:
1027     tcode += 3;
1028     break;
1029    
1030     /* Zero or more repeats of character types set the bits and then
1031     try again. */
1032    
1033     case OP_TYPEUPTO:
1034     case OP_TYPEMINUPTO:
1035 nigel 93 case OP_TYPEPOSUPTO:
1036 nigel 77 tcode += 2; /* Fall through */
1037    
1038     case OP_TYPESTAR:
1039     case OP_TYPEMINSTAR:
1040 nigel 93 case OP_TYPEPOSSTAR:
1041 nigel 77 case OP_TYPEQUERY:
1042     case OP_TYPEMINQUERY:
1043 nigel 93 case OP_TYPEPOSQUERY:
1044 nigel 77 switch(tcode[1])
1045     {
1046 ph10 523 default:
1047 nigel 77 case OP_ANY:
1048 ph10 345 case OP_ALLANY:
1049 nigel 93 return SSB_FAIL;
1050 ph10 535
1051 ph10 524 case OP_HSPACE:
1052     SET_BIT(0x09);
1053     SET_BIT(0x20);
1054     if (utf8)
1055 ph10 535 {
1056 ph10 545 SET_BIT(0xC2); /* For U+00A0 */
1057 ph10 524 SET_BIT(0xE1); /* For U+1680, U+180E */
1058     SET_BIT(0xE2); /* For U+2000 - U+200A, U+202F, U+205F */
1059 ph10 535 SET_BIT(0xE3); /* For U+3000 */
1060 ph10 524 }
1061 ph10 538 else SET_BIT(0xA0);
1062 ph10 535 break;
1063    
1064     case OP_ANYNL:
1065 ph10 524 case OP_VSPACE:
1066 ph10 535 SET_BIT(0x0A);
1067     SET_BIT(0x0B);
1068     SET_BIT(0x0C);
1069     SET_BIT(0x0D);
1070 ph10 545 if (utf8)
1071 ph10 538 {
1072 ph10 545 SET_BIT(0xC2); /* For U+0085 */
1073 ph10 538 SET_BIT(0xE2); /* For U+2028, U+2029 */
1074 ph10 545 }
1075 ph10 538 else SET_BIT(0x85);
1076 ph10 535 break;
1077    
1078 nigel 77 case OP_NOT_DIGIT:
1079 ph10 539 set_nottype_bits(start_bits, cbit_digit, table_limit, cd);
1080 nigel 77 break;
1081    
1082     case OP_DIGIT:
1083 ph10 539 set_type_bits(start_bits, cbit_digit, table_limit, cd);
1084 nigel 77 break;
1085    
1086 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
1087 ph10 539 ensure it gets set as not whitespace. */
1088 nigel 91
1089 nigel 77 case OP_NOT_WHITESPACE:
1090 ph10 539 set_nottype_bits(start_bits, cbit_space, table_limit, cd);
1091 ph10 545 start_bits[1] |= 0x08;
1092 nigel 77 break;
1093    
1094 nigel 91 /* The cbit_space table has vertical tab as whitespace; we have to
1095 ph10 539 avoid setting it. */
1096 nigel 91
1097 nigel 77 case OP_WHITESPACE:
1098 ph10 539 c = start_bits[1]; /* Save in case it was already set */
1099     set_type_bits(start_bits, cbit_space, table_limit, cd);
1100     start_bits[1] = (start_bits[1] & ~0x08) | c;
1101 nigel 77 break;
1102    
1103     case OP_NOT_WORDCHAR:
1104 ph10 539 set_nottype_bits(start_bits, cbit_word, table_limit, cd);
1105 nigel 77 break;
1106    
1107     case OP_WORDCHAR:
1108 ph10 539 set_type_bits(start_bits, cbit_word, table_limit, cd);
1109 nigel 77 break;
1110     }
1111    
1112     tcode += 2;
1113     break;
1114    
1115     /* Character class where all the information is in a bit map: set the
1116     bits and either carry on or not, according to the repeat count. If it was
1117     a negative class, and we are operating with UTF-8 characters, any byte
1118     with a value >= 0xc4 is a potentially valid starter because it starts a
1119     character with a value > 255. */
1120    
1121     case OP_NCLASS:
1122 ph10 111 #ifdef SUPPORT_UTF8
1123 nigel 77 if (utf8)
1124     {
1125     start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
1126     memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
1127     }
1128 ph10 111 #endif
1129 nigel 77 /* Fall through */
1130    
1131     case OP_CLASS:
1132     {
1133     tcode++;
1134    
1135     /* In UTF-8 mode, the bits in a bit map correspond to character
1136     values, not to byte values. However, the bit map we are constructing is
1137     for byte values. So we have to do a conversion for characters whose
1138     value is > 127. In fact, there are only two possible starting bytes for
1139     characters in the range 128 - 255. */
1140    
1141 ph10 107 #ifdef SUPPORT_UTF8
1142 nigel 77 if (utf8)
1143     {
1144     for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
1145     for (c = 128; c < 256; c++)
1146     {
1147     if ((tcode[c/8] && (1 << (c&7))) != 0)
1148     {
1149     int d = (c >> 6) | 0xc0; /* Set bit for this starter */
1150     start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
1151     c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
1152     }
1153     }
1154     }
1155    
1156     /* In non-UTF-8 mode, the two bit maps are completely compatible. */
1157    
1158     else
1159 ph10 111 #endif
1160 nigel 77 {
1161     for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
1162     }
1163    
1164 ph10 654 /* Advance past the bit map, and act on what follows. For a zero
1165 ph10 605 minimum repeat, continue; otherwise stop processing. */
1166 nigel 77
1167     tcode += 32;
1168     switch (*tcode)
1169     {
1170     case OP_CRSTAR:
1171     case OP_CRMINSTAR:
1172     case OP_CRQUERY:
1173     case OP_CRMINQUERY:
1174     tcode++;
1175     break;
1176    
1177     case OP_CRRANGE:
1178     case OP_CRMINRANGE:
1179     if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
1180     else try_next = FALSE;
1181     break;
1182 ph10 654
1183 nigel 77 default:
1184     try_next = FALSE;
1185     break;
1186     }
1187     }
1188     break; /* End of bitmap class handling */
1189    
1190     } /* End of switch */
1191     } /* End of try_next loop */
1192    
1193     code += GET(code, 1); /* Advance to next branch */
1194     }
1195     while (*code == OP_ALT);
1196 nigel 93 return yield;
1197 nigel 77 }
1198    
1199    
1200    
1201 ph10 605
1202    
1203 nigel 77 /*************************************************
1204     * Study a compiled expression *
1205     *************************************************/
1206    
1207     /* This function is handed a compiled expression that it must study to produce
1208     information that will speed up the matching. It returns a pcre_extra block
1209     which then gets handed back to pcre_exec().
1210    
1211     Arguments:
1212     re points to the compiled expression
1213     options contains option bits
1214     errorptr points to where to place error messages;
1215     set NULL unless error
1216    
1217     Returns: pointer to a pcre_extra block, with study_data filled in and the
1218 ph10 455 appropriate flags set;
1219 nigel 77 NULL on error or if no optimization possible
1220     */
1221    
1222 ph10 359 PCRE_EXP_DEFN pcre_extra * PCRE_CALL_CONVENTION
1223 nigel 77 pcre_study(const pcre *external_re, int options, const char **errorptr)
1224     {
1225 ph10 455 int min;
1226     BOOL bits_set = FALSE;
1227 nigel 77 uschar start_bits[32];
1228 ph10 688 pcre_extra *extra = NULL;
1229 nigel 77 pcre_study_data *study;
1230     const uschar *tables;
1231 nigel 91 uschar *code;
1232     compile_data compile_block;
1233 nigel 77 const real_pcre *re = (const real_pcre *)external_re;
1234    
1235     *errorptr = NULL;
1236    
1237     if (re == NULL || re->magic_number != MAGIC_NUMBER)
1238     {
1239     *errorptr = "argument is not a compiled regular expression";
1240     return NULL;
1241     }
1242    
1243     if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
1244     {
1245     *errorptr = "unknown or incorrect option bit(s) set";
1246     return NULL;
1247     }
1248    
1249 nigel 91 code = (uschar *)re + re->name_table_offset +
1250     (re->name_count * re->name_entry_size);
1251    
1252 nigel 77 /* For an anchored pattern, or an unanchored pattern that has a first char, or
1253 ph10 461 a multiline pattern that matches only at "line starts", there is no point in
1254 ph10 455 seeking a list of starting bytes. */
1255 nigel 77
1256 ph10 455 if ((re->options & PCRE_ANCHORED) == 0 &&
1257     (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) == 0)
1258     {
1259 ph10 605 int rc;
1260    
1261 ph10 455 /* Set the character tables in the block that is passed around */
1262 ph10 461
1263 ph10 455 tables = re->tables;
1264     if (tables == NULL)
1265     (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
1266     (void *)(&tables));
1267 ph10 461
1268 ph10 455 compile_block.lcc = tables + lcc_offset;
1269     compile_block.fcc = tables + fcc_offset;
1270     compile_block.cbits = tables + cbits_offset;
1271     compile_block.ctypes = tables + ctypes_offset;
1272 ph10 461
1273 ph10 455 /* See if we can find a fixed set of initial characters for the pattern. */
1274 ph10 461
1275 ph10 455 memset(start_bits, 0, 32 * sizeof(uschar));
1276 ph10 605 rc = set_start_bits(code, start_bits, (re->options & PCRE_UTF8) != 0,
1277     &compile_block);
1278     bits_set = rc == SSB_DONE;
1279 ph10 691 if (rc == SSB_UNKNOWN)
1280 ph10 688 {
1281     *errorptr = "internal error: opcode not recognized";
1282     return NULL;
1283 ph10 691 }
1284 ph10 455 }
1285 ph10 461
1286 ph10 455 /* Find the minimum length of subject string. */
1287 nigel 77
1288 ph10 697 switch(min = find_minlength(code, code, re->options, 0))
1289 ph10 603 {
1290 ph10 688 case -2: *errorptr = "internal error: missing capturing bracket"; return NULL;
1291     case -3: *errorptr = "internal error: opcode not recognized"; return NULL;
1292 ph10 603 default: break;
1293 ph10 605 }
1294 ph10 708
1295 ph10 688 /* If a set of starting bytes has been identified, or if the minimum length is
1296     greater than zero, or if JIT optimization has been requested, get a pcre_extra
1297     block and a pcre_study_data block. The study data is put in the latter, which
1298     is pointed to by the former, which may also get additional data set later by
1299     the calling program. At the moment, the size of pcre_study_data is fixed. We
1300     nevertheless save it in a field for returning via the pcre_fullinfo() function
1301     so that if it becomes variable in the future, we don't have to change that
1302     code. */
1303 nigel 77
1304 ph10 691 if (bits_set || min > 0
1305 ph10 688 #ifdef SUPPORT_JIT
1306     || (options & PCRE_STUDY_JIT_COMPILE) != 0
1307     #endif
1308     )
1309 nigel 77 {
1310 ph10 688 extra = (pcre_extra *)(pcre_malloc)
1311     (sizeof(pcre_extra) + sizeof(pcre_study_data));
1312     if (extra == NULL)
1313     {
1314     *errorptr = "failed to get memory";
1315     return NULL;
1316     }
1317 ph10 691
1318 ph10 688 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
1319     extra->flags = PCRE_EXTRA_STUDY_DATA;
1320     extra->study_data = study;
1321 ph10 691
1322 ph10 688 study->size = sizeof(pcre_study_data);
1323     study->flags = 0;
1324 ph10 691
1325 ph10 688 if (bits_set)
1326     {
1327     study->flags |= PCRE_STUDY_MAPPED;
1328     memcpy(study->start_bits, start_bits, sizeof(start_bits));
1329     }
1330 ph10 691
1331     /* Always set the minlength value in the block, because the JIT compiler
1332     makes use of it. However, don't set the bit unless the length is greater than
1333     zero - the interpretive pcre_exec() and pcre_dfa_exec() needn't waste time
1334 ph10 697 checking the zero case. */
1335 ph10 691
1336 ph10 708 if (min > 0)
1337 ph10 697 {
1338     study->flags |= PCRE_STUDY_MINLEN;
1339     study->minlength = min;
1340     }
1341 ph10 708 else study->minlength = 0;
1342 ph10 691
1343 ph10 688 /* If JIT support was compiled and requested, attempt the JIT compilation.
1344     If no starting bytes were found, and the minimum length is zero, and JIT
1345 ph10 689 compilation fails, abandon the extra block and return NULL. */
1346 ph10 691
1347 ph10 666 #ifdef SUPPORT_JIT
1348 ph10 688 extra->executable_jit = NULL;
1349     if ((options & PCRE_STUDY_JIT_COMPILE) != 0) _pcre_jit_compile(re, extra);
1350 ph10 689 if (study->flags == 0 && (extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) == 0)
1351 ph10 688 {
1352     pcre_free_study(extra);
1353     extra = NULL;
1354 ph10 691 }
1355 ph10 666 #endif
1356 ph10 688 }
1357 ph10 666
1358 nigel 77 return extra;
1359     }
1360    
1361 ph10 666
1362     /*************************************************
1363     * Free the study data *
1364     *************************************************/
1365    
1366     /* This function frees the memory that was obtained by pcre_study().
1367    
1368     Argument: a pointer to the pcre_extra block
1369     Returns: nothing
1370     */
1371    
1372     PCRE_EXP_DEFN void
1373     pcre_free_study(pcre_extra *extra)
1374     {
1375     #ifdef SUPPORT_JIT
1376 ph10 691 if ((extra->flags & PCRE_EXTRA_EXECUTABLE_JIT) != 0 &&
1377 ph10 666 extra->executable_jit != NULL)
1378     _pcre_jit_free(extra->executable_jit);
1379     #endif
1380     pcre_free(extra);
1381     }
1382    
1383 nigel 77 /* End of pcre_study.c */

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