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Revision 199 - (show annotations) (download)
Tue Jul 31 14:39:09 2007 UTC (7 years ago) by ph10
File MIME type: text/plain
File size: 17805 byte(s)
Daniel's patch for config.h and Windows DLL declarations (not fully working).

1 /*************************************************
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 Copyright (c) 1997-2007 University of Cambridge
10
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 #ifdef HAVE_CONFIG_H
46 #include <config.h>
47 #endif
48
49 #include "pcre_internal.h"
50
51
52 /* Returns from set_start_bits() */
53
54 enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE };
55
56
57 /*************************************************
58 * Set a bit and maybe its alternate case *
59 *************************************************/
60
61 /* Given a character, set its bit in the table, and also the bit for the other
62 version of a letter if we are caseless.
63
64 Arguments:
65 start_bits points to the bit map
66 c is the character
67 caseless the caseless flag
68 cd the block with char table pointers
69
70 Returns: nothing
71 */
72
73 static void
74 set_bit(uschar *start_bits, unsigned int c, BOOL caseless, compile_data *cd)
75 {
76 start_bits[c/8] |= (1 << (c&7));
77 if (caseless && (cd->ctypes[c] & ctype_letter) != 0)
78 start_bits[cd->fcc[c]/8] |= (1 << (cd->fcc[c]&7));
79 }
80
81
82
83 /*************************************************
84 * Create bitmap of starting bytes *
85 *************************************************/
86
87 /* This function scans a compiled unanchored expression recursively and
88 attempts to build a bitmap of the set of possible starting bytes. As time goes
89 by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
90 useful for parenthesized groups in patterns such as (a*)b where the group
91 provides some optional starting bytes but scanning must continue at the outer
92 level to find at least one mandatory byte. At the outermost level, this
93 function fails unless the result is SSB_DONE.
94
95 Arguments:
96 code points to an expression
97 start_bits points to a 32-byte table, initialized to 0
98 caseless the current state of the caseless flag
99 utf8 TRUE if in UTF-8 mode
100 cd the block with char table pointers
101
102 Returns: SSB_FAIL => Failed to find any starting bytes
103 SSB_DONE => Found mandatory starting bytes
104 SSB_CONTINUE => Found optional starting bytes
105 */
106
107 static int
108 set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
109 BOOL utf8, compile_data *cd)
110 {
111 register int c;
112 int yield = SSB_DONE;
113
114 #if 0
115 /* ========================================================================= */
116 /* The following comment and code was inserted in January 1999. In May 2006,
117 when it was observed to cause compiler warnings about unused values, I took it
118 out again. If anybody is still using OS/2, they will have to put it back
119 manually. */
120
121 /* This next statement and the later reference to dummy are here in order to
122 trick the optimizer of the IBM C compiler for OS/2 into generating correct
123 code. Apparently IBM isn't going to fix the problem, and we would rather not
124 disable optimization (in this module it actually makes a big difference, and
125 the pcre module can use all the optimization it can get). */
126
127 volatile int dummy;
128 /* ========================================================================= */
129 #endif
130
131 do
132 {
133 const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
134 BOOL try_next = TRUE;
135
136 while (try_next) /* Loop for items in this branch */
137 {
138 int rc;
139 switch(*tcode)
140 {
141 /* Fail if we reach something we don't understand */
142
143 default:
144 return SSB_FAIL;
145
146 /* If we hit a bracket or a positive lookahead assertion, recurse to set
147 bits from within the subpattern. If it can't find anything, we have to
148 give up. If it finds some mandatory character(s), we are done for this
149 branch. Otherwise, carry on scanning after the subpattern. */
150
151 case OP_BRA:
152 case OP_SBRA:
153 case OP_CBRA:
154 case OP_SCBRA:
155 case OP_ONCE:
156 case OP_ASSERT:
157 rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
158 if (rc == SSB_FAIL) return SSB_FAIL;
159 if (rc == SSB_DONE) try_next = FALSE; else
160 {
161 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
162 tcode += 1 + LINK_SIZE;
163 }
164 break;
165
166 /* If we hit ALT or KET, it means we haven't found anything mandatory in
167 this branch, though we might have found something optional. For ALT, we
168 continue with the next alternative, but we have to arrange that the final
169 result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
170 return SSB_CONTINUE: if this is the top level, that indicates failure,
171 but after a nested subpattern, it causes scanning to continue. */
172
173 case OP_ALT:
174 yield = SSB_CONTINUE;
175 try_next = FALSE;
176 break;
177
178 case OP_KET:
179 case OP_KETRMAX:
180 case OP_KETRMIN:
181 return SSB_CONTINUE;
182
183 /* Skip over callout */
184
185 case OP_CALLOUT:
186 tcode += 2 + 2*LINK_SIZE;
187 break;
188
189 /* Skip over lookbehind and negative lookahead assertions */
190
191 case OP_ASSERT_NOT:
192 case OP_ASSERTBACK:
193 case OP_ASSERTBACK_NOT:
194 do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
195 tcode += 1 + LINK_SIZE;
196 break;
197
198 /* Skip over an option setting, changing the caseless flag */
199
200 case OP_OPT:
201 caseless = (tcode[1] & PCRE_CASELESS) != 0;
202 tcode += 2;
203 break;
204
205 /* BRAZERO does the bracket, but carries on. */
206
207 case OP_BRAZERO:
208 case OP_BRAMINZERO:
209 if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
210 return SSB_FAIL;
211 /* =========================================================================
212 See the comment at the head of this function concerning the next line,
213 which was an old fudge for the benefit of OS/2.
214 dummy = 1;
215 ========================================================================= */
216 do tcode += GET(tcode,1); while (*tcode == OP_ALT);
217 tcode += 1 + LINK_SIZE;
218 break;
219
220 /* Single-char * or ? sets the bit and tries the next item */
221
222 case OP_STAR:
223 case OP_MINSTAR:
224 case OP_POSSTAR:
225 case OP_QUERY:
226 case OP_MINQUERY:
227 case OP_POSQUERY:
228 set_bit(start_bits, tcode[1], caseless, cd);
229 tcode += 2;
230 #ifdef SUPPORT_UTF8
231 if (utf8 && tcode[-1] >= 0xc0)
232 tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
233 #endif
234 break;
235
236 /* Single-char upto sets the bit and tries the next */
237
238 case OP_UPTO:
239 case OP_MINUPTO:
240 case OP_POSUPTO:
241 set_bit(start_bits, tcode[3], caseless, cd);
242 tcode += 4;
243 #ifdef SUPPORT_UTF8
244 if (utf8 && tcode[-1] >= 0xc0)
245 tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
246 #endif
247 break;
248
249 /* At least one single char sets the bit and stops */
250
251 case OP_EXACT: /* Fall through */
252 tcode += 2;
253
254 case OP_CHAR:
255 case OP_CHARNC:
256 case OP_PLUS:
257 case OP_MINPLUS:
258 case OP_POSPLUS:
259 set_bit(start_bits, tcode[1], caseless, cd);
260 try_next = FALSE;
261 break;
262
263 /* Single character type sets the bits and stops */
264
265 case OP_NOT_DIGIT:
266 for (c = 0; c < 32; c++)
267 start_bits[c] |= ~cd->cbits[c+cbit_digit];
268 try_next = FALSE;
269 break;
270
271 case OP_DIGIT:
272 for (c = 0; c < 32; c++)
273 start_bits[c] |= cd->cbits[c+cbit_digit];
274 try_next = FALSE;
275 break;
276
277 /* The cbit_space table has vertical tab as whitespace; we have to
278 discard it. */
279
280 case OP_NOT_WHITESPACE:
281 for (c = 0; c < 32; c++)
282 {
283 int d = cd->cbits[c+cbit_space];
284 if (c == 1) d &= ~0x08;
285 start_bits[c] |= ~d;
286 }
287 try_next = FALSE;
288 break;
289
290 /* The cbit_space table has vertical tab as whitespace; we have to
291 discard it. */
292
293 case OP_WHITESPACE:
294 for (c = 0; c < 32; c++)
295 {
296 int d = cd->cbits[c+cbit_space];
297 if (c == 1) d &= ~0x08;
298 start_bits[c] |= d;
299 }
300 try_next = FALSE;
301 break;
302
303 case OP_NOT_WORDCHAR:
304 for (c = 0; c < 32; c++)
305 start_bits[c] |= ~cd->cbits[c+cbit_word];
306 try_next = FALSE;
307 break;
308
309 case OP_WORDCHAR:
310 for (c = 0; c < 32; c++)
311 start_bits[c] |= cd->cbits[c+cbit_word];
312 try_next = FALSE;
313 break;
314
315 /* One or more character type fudges the pointer and restarts, knowing
316 it will hit a single character type and stop there. */
317
318 case OP_TYPEPLUS:
319 case OP_TYPEMINPLUS:
320 tcode++;
321 break;
322
323 case OP_TYPEEXACT:
324 tcode += 3;
325 break;
326
327 /* Zero or more repeats of character types set the bits and then
328 try again. */
329
330 case OP_TYPEUPTO:
331 case OP_TYPEMINUPTO:
332 case OP_TYPEPOSUPTO:
333 tcode += 2; /* Fall through */
334
335 case OP_TYPESTAR:
336 case OP_TYPEMINSTAR:
337 case OP_TYPEPOSSTAR:
338 case OP_TYPEQUERY:
339 case OP_TYPEMINQUERY:
340 case OP_TYPEPOSQUERY:
341 switch(tcode[1])
342 {
343 case OP_ANY:
344 return SSB_FAIL;
345
346 case OP_NOT_DIGIT:
347 for (c = 0; c < 32; c++)
348 start_bits[c] |= ~cd->cbits[c+cbit_digit];
349 break;
350
351 case OP_DIGIT:
352 for (c = 0; c < 32; c++)
353 start_bits[c] |= cd->cbits[c+cbit_digit];
354 break;
355
356 /* The cbit_space table has vertical tab as whitespace; we have to
357 discard it. */
358
359 case OP_NOT_WHITESPACE:
360 for (c = 0; c < 32; c++)
361 {
362 int d = cd->cbits[c+cbit_space];
363 if (c == 1) d &= ~0x08;
364 start_bits[c] |= ~d;
365 }
366 break;
367
368 /* The cbit_space table has vertical tab as whitespace; we have to
369 discard it. */
370
371 case OP_WHITESPACE:
372 for (c = 0; c < 32; c++)
373 {
374 int d = cd->cbits[c+cbit_space];
375 if (c == 1) d &= ~0x08;
376 start_bits[c] |= d;
377 }
378 break;
379
380 case OP_NOT_WORDCHAR:
381 for (c = 0; c < 32; c++)
382 start_bits[c] |= ~cd->cbits[c+cbit_word];
383 break;
384
385 case OP_WORDCHAR:
386 for (c = 0; c < 32; c++)
387 start_bits[c] |= cd->cbits[c+cbit_word];
388 break;
389 }
390
391 tcode += 2;
392 break;
393
394 /* Character class where all the information is in a bit map: set the
395 bits and either carry on or not, according to the repeat count. If it was
396 a negative class, and we are operating with UTF-8 characters, any byte
397 with a value >= 0xc4 is a potentially valid starter because it starts a
398 character with a value > 255. */
399
400 case OP_NCLASS:
401 #ifdef SUPPORT_UTF8
402 if (utf8)
403 {
404 start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
405 memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
406 }
407 #endif
408 /* Fall through */
409
410 case OP_CLASS:
411 {
412 tcode++;
413
414 /* In UTF-8 mode, the bits in a bit map correspond to character
415 values, not to byte values. However, the bit map we are constructing is
416 for byte values. So we have to do a conversion for characters whose
417 value is > 127. In fact, there are only two possible starting bytes for
418 characters in the range 128 - 255. */
419
420 #ifdef SUPPORT_UTF8
421 if (utf8)
422 {
423 for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
424 for (c = 128; c < 256; c++)
425 {
426 if ((tcode[c/8] && (1 << (c&7))) != 0)
427 {
428 int d = (c >> 6) | 0xc0; /* Set bit for this starter */
429 start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
430 c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
431 }
432 }
433 }
434
435 /* In non-UTF-8 mode, the two bit maps are completely compatible. */
436
437 else
438 #endif
439 {
440 for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
441 }
442
443 /* Advance past the bit map, and act on what follows */
444
445 tcode += 32;
446 switch (*tcode)
447 {
448 case OP_CRSTAR:
449 case OP_CRMINSTAR:
450 case OP_CRQUERY:
451 case OP_CRMINQUERY:
452 tcode++;
453 break;
454
455 case OP_CRRANGE:
456 case OP_CRMINRANGE:
457 if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
458 else try_next = FALSE;
459 break;
460
461 default:
462 try_next = FALSE;
463 break;
464 }
465 }
466 break; /* End of bitmap class handling */
467
468 } /* End of switch */
469 } /* End of try_next loop */
470
471 code += GET(code, 1); /* Advance to next branch */
472 }
473 while (*code == OP_ALT);
474 return yield;
475 }
476
477
478
479 /*************************************************
480 * Study a compiled expression *
481 *************************************************/
482
483 /* This function is handed a compiled expression that it must study to produce
484 information that will speed up the matching. It returns a pcre_extra block
485 which then gets handed back to pcre_exec().
486
487 Arguments:
488 re points to the compiled expression
489 options contains option bits
490 errorptr points to where to place error messages;
491 set NULL unless error
492
493 Returns: pointer to a pcre_extra block, with study_data filled in and the
494 appropriate flag set;
495 NULL on error or if no optimization possible
496 */
497
498 PCRE_EXP_DEFN pcre_extra *
499 pcre_study(const pcre *external_re, int options, const char **errorptr)
500 {
501 uschar start_bits[32];
502 pcre_extra *extra;
503 pcre_study_data *study;
504 const uschar *tables;
505 uschar *code;
506 compile_data compile_block;
507 const real_pcre *re = (const real_pcre *)external_re;
508
509 *errorptr = NULL;
510
511 if (re == NULL || re->magic_number != MAGIC_NUMBER)
512 {
513 *errorptr = "argument is not a compiled regular expression";
514 return NULL;
515 }
516
517 if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
518 {
519 *errorptr = "unknown or incorrect option bit(s) set";
520 return NULL;
521 }
522
523 code = (uschar *)re + re->name_table_offset +
524 (re->name_count * re->name_entry_size);
525
526 /* For an anchored pattern, or an unanchored pattern that has a first char, or
527 a multiline pattern that matches only at "line starts", no further processing
528 at present. */
529
530 if ((re->options & (PCRE_ANCHORED|PCRE_FIRSTSET|PCRE_STARTLINE)) != 0)
531 return NULL;
532
533 /* Set the character tables in the block that is passed around */
534
535 tables = re->tables;
536 if (tables == NULL)
537 (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
538 (void *)(&tables));
539
540 compile_block.lcc = tables + lcc_offset;
541 compile_block.fcc = tables + fcc_offset;
542 compile_block.cbits = tables + cbits_offset;
543 compile_block.ctypes = tables + ctypes_offset;
544
545 /* See if we can find a fixed set of initial characters for the pattern. */
546
547 memset(start_bits, 0, 32 * sizeof(uschar));
548 if (set_start_bits(code, start_bits, (re->options & PCRE_CASELESS) != 0,
549 (re->options & PCRE_UTF8) != 0, &compile_block) != SSB_DONE) return NULL;
550
551 /* Get a pcre_extra block and a pcre_study_data block. The study data is put in
552 the latter, which is pointed to by the former, which may also get additional
553 data set later by the calling program. At the moment, the size of
554 pcre_study_data is fixed. We nevertheless save it in a field for returning via
555 the pcre_fullinfo() function so that if it becomes variable in the future, we
556 don't have to change that code. */
557
558 extra = (pcre_extra *)(pcre_malloc)
559 (sizeof(pcre_extra) + sizeof(pcre_study_data));
560
561 if (extra == NULL)
562 {
563 *errorptr = "failed to get memory";
564 return NULL;
565 }
566
567 study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
568 extra->flags = PCRE_EXTRA_STUDY_DATA;
569 extra->study_data = study;
570
571 study->size = sizeof(pcre_study_data);
572 study->options = PCRE_STUDY_MAPPED;
573 memcpy(study->start_bits, start_bits, sizeof(start_bits));
574
575 return extra;
576 }
577
578 /* End of pcre_study.c */

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