src/src/pcre/pcre_get.c

   1 /* $Cambridge: exim/src/src/pcre/pcre_get.c,v 1.6 2007/11/12 13:02:19 nm4 Exp $ */
   2
   3 /*************************************************
   4 *      Perl-Compatible Regular Expressions       *
   5 *************************************************/
   6
   7 /* PCRE is a library of functions to support regular expressions whose syntax
   8 and semantics are as close as possible to those of the Perl 5 language.
   9
  10                        Written by Philip Hazel
  11            Copyright (c) 1997-2007 University of Cambridge
  12
  13 -----------------------------------------------------------------------------
  14 Redistribution and use in source and binary forms, with or without
  15 modification, are permitted provided that the following conditions are met:
  16
  17     * Redistributions of source code must retain the above copyright notice,
  18       this list of conditions and the following disclaimer.
  19
  20     * Redistributions in binary form must reproduce the above copyright
  21       notice, this list of conditions and the following disclaimer in the
  22       documentation and/or other materials provided with the distribution.
  23
  24     * Neither the name of the University of Cambridge nor the names of its
  25       contributors may be used to endorse or promote products derived from
  26       this software without specific prior written permission.
  27
  28 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  29 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  32 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  33 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  34 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  35 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  36 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  37 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 POSSIBILITY OF SUCH DAMAGE.
  39 -----------------------------------------------------------------------------
  40 */
  41
  42
  43 /* This module contains some convenience functions for extracting substrings
  44 from the subject string after a regex match has succeeded. The original idea
  45 for these functions came from Scott Wimer. */
  46
  47
  48 #ifdef HAVE_CONFIG_H
  49 #include "config.h"
  50 #endif
  51
  52 #include "pcre_internal.h"
  53
  54
  55 /*************************************************
  56 *           Find number for named string         *
  57 *************************************************/
  58
  59 /* This function is used by the get_first_set() function below, as well
  60 as being generally available. It assumes that names are unique.
  61
  62 Arguments:
  63   code        the compiled regex
  64   stringname  the name whose number is required
  65
  66 Returns:      the number of the named parentheses, or a negative number
  67                 (PCRE_ERROR_NOSUBSTRING) if not found
  68 */
  69
  70 int
  71 pcre_get_stringnumber(const pcre *code, const char *stringname)
  72 {
  73 int rc;
  74 int entrysize;
  75 int top, bot;
  76 uschar *nametable;
  77
  78 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMECOUNT, &top)) != 0)
  79   return rc;
  80 if (top <= 0) return PCRE_ERROR_NOSUBSTRING;
  81
  82 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMEENTRYSIZE, &entrysize)) != 0)
  83   return rc;
  84 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMETABLE, &nametable)) != 0)
  85   return rc;
  86
  87 bot = 0;
  88 while (top > bot)
  89   {
  90   int mid = (top + bot) / 2;
  91   uschar *entry = nametable + entrysize*mid;
  92   int c = strcmp(stringname, (char *)(entry + 2));
  93   if (c == 0) return (entry[0] << 8) + entry[1];
  94   if (c > 0) bot = mid + 1; else top = mid;
  95   }
  96
  97 return PCRE_ERROR_NOSUBSTRING;
  98 }
  99
 100
 101
 102 /*************************************************
 103 *     Find (multiple) entries for named string   *
 104 *************************************************/
 105
 106 /* This is used by the get_first_set() function below, as well as being
 107 generally available. It is used when duplicated names are permitted.
 108
 109 Arguments:
 110   code        the compiled regex
 111   stringname  the name whose entries required
 112   firstptr    where to put the pointer to the first entry
 113   lastptr     where to put the pointer to the last entry
 114
 115 Returns:      the length of each entry, or a negative number
 116                 (PCRE_ERROR_NOSUBSTRING) if not found
 117 */
 118
 119 int
 120 pcre_get_stringtable_entries(const pcre *code, const char *stringname,
 121   char **firstptr, char **lastptr)
 122 {
 123 int rc;
 124 int entrysize;
 125 int top, bot;
 126 uschar *nametable, *lastentry;
 127
 128 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMECOUNT, &top)) != 0)
 129   return rc;
 130 if (top <= 0) return PCRE_ERROR_NOSUBSTRING;
 131
 132 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMEENTRYSIZE, &entrysize)) != 0)
 133   return rc;
 134 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMETABLE, &nametable)) != 0)
 135   return rc;
 136
 137 lastentry = nametable + entrysize * (top - 1);
 138 bot = 0;
 139 while (top > bot)
 140   {
 141   int mid = (top + bot) / 2;
 142   uschar *entry = nametable + entrysize*mid;
 143   int c = strcmp(stringname, (char *)(entry + 2));
 144   if (c == 0)
 145     {
 146     uschar *first = entry;
 147     uschar *last = entry;
 148     while (first > nametable)
 149       {
 150       if (strcmp(stringname, (char *)(first - entrysize + 2)) != 0) break;
 151       first -= entrysize;
 152       }
 153     while (last < lastentry)
 154       {
 155       if (strcmp(stringname, (char *)(last + entrysize + 2)) != 0) break;
 156       last += entrysize;
 157       }
 158     *firstptr = (char *)first;
 159     *lastptr = (char *)last;
 160     return entrysize;
 161     }
 162   if (c > 0) bot = mid + 1; else top = mid;
 163   }
 164
 165 return PCRE_ERROR_NOSUBSTRING;
 166 }
 167
 168
 169
 170 /*************************************************
 171 *    Find first set of multiple named strings    *
 172 *************************************************/
 173
 174 /* This function allows for duplicate names in the table of named substrings.
 175 It returns the number of the first one that was set in a pattern match.
 176
 177 Arguments:
 178   code         the compiled regex
 179   stringname   the name of the capturing substring
 180   ovector      the vector of matched substrings
 181
 182 Returns:       the number of the first that is set,
 183                or the number of the last one if none are set,
 184                or a negative number on error
 185 */
 186
 187 static int
 188 get_first_set(const pcre *code, const char *stringname, int *ovector)
 189 {
 190 const real_pcre *re = (const real_pcre *)code;
 191 int entrysize;
 192 char *first, *last;
 193 uschar *entry;
 194 if ((re->options & PCRE_DUPNAMES) == 0 && (re->flags & PCRE_JCHANGED) == 0)
 195   return pcre_get_stringnumber(code, stringname);
 196 entrysize = pcre_get_stringtable_entries(code, stringname, &first, &last);
 197 if (entrysize <= 0) return entrysize;
 198 for (entry = (uschar *)first; entry <= (uschar *)last; entry += entrysize)
 199   {
 200   int n = (entry[0] << 8) + entry[1];
 201   if (ovector[n*2] >= 0) return n;
 202   }
 203 return (first[0] << 8) + first[1];
 204 }
 205
 206
 207
 208
 209 /*************************************************
 210 *      Copy captured string to given buffer      *
 211 *************************************************/
 212
 213 /* This function copies a single captured substring into a given buffer.
 214 Note that we use memcpy() rather than strncpy() in case there are binary zeros
 215 in the string.
 216
 217 Arguments:
 218   subject        the subject string that was matched
 219   ovector        pointer to the offsets table
 220   stringcount    the number of substrings that were captured
 221                    (i.e. the yield of the pcre_exec call, unless
 222                    that was zero, in which case it should be 1/3
 223                    of the offset table size)
 224   stringnumber   the number of the required substring
 225   buffer         where to put the substring
 226   size           the size of the buffer
 227
 228 Returns:         if successful:
 229                    the length of the copied string, not including the zero
 230                    that is put on the end; can be zero
 231                  if not successful:
 232                    PCRE_ERROR_NOMEMORY (-6) buffer too small
 233                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 234 */
 235
 236 int
 237 pcre_copy_substring(const char *subject, int *ovector, int stringcount,
 238   int stringnumber, char *buffer, int size)
 239 {
 240 int yield;
 241 if (stringnumber < 0 || stringnumber >= stringcount)
 242   return PCRE_ERROR_NOSUBSTRING;
 243 stringnumber *= 2;
 244 yield = ovector[stringnumber+1] - ovector[stringnumber];
 245 if (size < yield + 1) return PCRE_ERROR_NOMEMORY;
 246 memcpy(buffer, subject + ovector[stringnumber], yield);
 247 buffer[yield] = 0;
 248 return yield;
 249 }
 250
 251
 252
 253 /*************************************************
 254 *   Copy named captured string to given buffer   *
 255 *************************************************/
 256
 257 /* This function copies a single captured substring into a given buffer,
 258 identifying it by name. If the regex permits duplicate names, the first
 259 substring that is set is chosen.
 260
 261 Arguments:
 262   code           the compiled regex
 263   subject        the subject string that was matched
 264   ovector        pointer to the offsets table
 265   stringcount    the number of substrings that were captured
 266                    (i.e. the yield of the pcre_exec call, unless
 267                    that was zero, in which case it should be 1/3
 268                    of the offset table size)
 269   stringname     the name of the required substring
 270   buffer         where to put the substring
 271   size           the size of the buffer
 272
 273 Returns:         if successful:
 274                    the length of the copied string, not including the zero
 275                    that is put on the end; can be zero
 276                  if not successful:
 277                    PCRE_ERROR_NOMEMORY (-6) buffer too small
 278                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 279 */
 280
 281 int
 282 pcre_copy_named_substring(const pcre *code, const char *subject, int *ovector,
 283   int stringcount, const char *stringname, char *buffer, int size)
 284 {
 285 int n = get_first_set(code, stringname, ovector);
 286 if (n <= 0) return n;
 287 return pcre_copy_substring(subject, ovector, stringcount, n, buffer, size);
 288 }
 289
 290
 291
 292 /*************************************************
 293 *      Copy all captured strings to new store    *
 294 *************************************************/
 295
 296 /* This function gets one chunk of store and builds a list of pointers and all
 297 of the captured substrings in it. A NULL pointer is put on the end of the list.
 298
 299 Arguments:
 300   subject        the subject string that was matched
 301   ovector        pointer to the offsets table
 302   stringcount    the number of substrings that were captured
 303                    (i.e. the yield of the pcre_exec call, unless
 304                    that was zero, in which case it should be 1/3
 305                    of the offset table size)
 306   listptr        set to point to the list of pointers
 307
 308 Returns:         if successful: 0
 309                  if not successful:
 310                    PCRE_ERROR_NOMEMORY (-6) failed to get store
 311 */
 312
 313 int
 314 pcre_get_substring_list(const char *subject, int *ovector, int stringcount,
 315   const char ***listptr)
 316 {
 317 int i;
 318 int size = sizeof(char *);
 319 int double_count = stringcount * 2;
 320 char **stringlist;
 321 char *p;
 322
 323 for (i = 0; i < double_count; i += 2)
 324   size += sizeof(char *) + ovector[i+1] - ovector[i] + 1;
 325
 326 stringlist = (char **)(pcre_malloc)(size);
 327 if (stringlist == NULL) return PCRE_ERROR_NOMEMORY;
 328
 329 *listptr = (const char **)stringlist;
 330 p = (char *)(stringlist + stringcount + 1);
 331
 332 for (i = 0; i < double_count; i += 2)
 333   {
 334   int len = ovector[i+1] - ovector[i];
 335   memcpy(p, subject + ovector[i], len);
 336   *stringlist++ = p;
 337   p += len;
 338   *p++ = 0;
 339   }
 340
 341 *stringlist = NULL;
 342 return 0;
 343 }
 344
 345
 346
 347 /*************************************************
 348 *   Free store obtained by get_substring_list    *
 349 *************************************************/
 350
 351 /* This function exists for the benefit of people calling PCRE from non-C
 352 programs that can call its functions, but not free() or (pcre_free)() directly.
 353
 354 Argument:   the result of a previous pcre_get_substring_list()
 355 Returns:    nothing
 356 */
 357
 358 void
 359 pcre_free_substring_list(const char **pointer)
 360 {
 361 (pcre_free)((void *)pointer);
 362 }
 363
 364
 365
 366 /*************************************************
 367 *      Copy captured string to new store         *
 368 *************************************************/
 369
 370 /* This function copies a single captured substring into a piece of new
 371 store
 372
 373 Arguments:
 374   subject        the subject string that was matched
 375   ovector        pointer to the offsets table
 376   stringcount    the number of substrings that were captured
 377                    (i.e. the yield of the pcre_exec call, unless
 378                    that was zero, in which case it should be 1/3
 379                    of the offset table size)
 380   stringnumber   the number of the required substring
 381   stringptr      where to put a pointer to the substring
 382
 383 Returns:         if successful:
 384                    the length of the string, not including the zero that
 385                    is put on the end; can be zero
 386                  if not successful:
 387                    PCRE_ERROR_NOMEMORY (-6) failed to get store
 388                    PCRE_ERROR_NOSUBSTRING (-7) substring not present
 389 */
 390
 391 int
 392 pcre_get_substring(const char *subject, int *ovector, int stringcount,
 393   int stringnumber, const char **stringptr)
 394 {
 395 int yield;
 396 char *substring;
 397 if (stringnumber < 0 || stringnumber >= stringcount)
 398   return PCRE_ERROR_NOSUBSTRING;
 399 stringnumber *= 2;
 400 yield = ovector[stringnumber+1] - ovector[stringnumber];
 401 substring = (char *)(pcre_malloc)(yield + 1);
 402 if (substring == NULL) return PCRE_ERROR_NOMEMORY;
 403 memcpy(substring, subject + ovector[stringnumber], yield);
 404 substring[yield] = 0;
 405 *stringptr = substring;
 406 return yield;
 407 }
 408
 409
 410
 411 /*************************************************
 412 *   Copy named captured string to new store      *
 413 *************************************************/
 414
 415 /* This function copies a single captured substring, identified by name, into
 416 new store. If the regex permits duplicate names, the first substring that is
 417 set is chosen.
 418
 419 Arguments:
 420   code           the compiled regex
 421   subject        the subject string that was matched
 422   ovector        pointer to the offsets table
 423   stringcount    the number of substrings that were captured
 424                    (i.e. the yield of the pcre_exec call, unless
 425                    that was zero, in which case it should be 1/3
 426                    of the offset table size)
 427   stringname     the name of the required substring
 428   stringptr      where to put the pointer
 429
 430 Returns:         if successful:
 431                    the length of the copied string, not including the zero
 432                    that is put on the end; can be zero
 433                  if not successful:
 434                    PCRE_ERROR_NOMEMORY (-6) couldn't get memory
 435                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 436 */
 437
 438 int
 439 pcre_get_named_substring(const pcre *code, const char *subject, int *ovector,
 440   int stringcount, const char *stringname, const char **stringptr)
 441 {
 442 int n = get_first_set(code, stringname, ovector);
 443 if (n <= 0) return n;
 444 return pcre_get_substring(subject, ovector, stringcount, n, stringptr);
 445 }
 446
 447
 448
 449
 450 /*************************************************
 451 *       Free store obtained by get_substring     *
 452 *************************************************/
 453
 454 /* This function exists for the benefit of people calling PCRE from non-C
 455 programs that can call its functions, but not free() or (pcre_free)() directly.
 456
 457 Argument:   the result of a previous pcre_get_substring()
 458 Returns:    nothing
 459 */
 460
 461 void
 462 pcre_free_substring(const char *pointer)
 463 {
 464 (pcre_free)((void *)pointer);
 465 }
 466
 467 /* End of pcre_get.c */