src/src/pcre/get.c

   1 /*************************************************
   2 *      Perl-Compatible Regular Expressions       *
   3 *************************************************/
   4
   5 /*
   6 This is a library of functions to support regular expressions whose syntax
   7 and semantics are as close as possible to those of the Perl 5 language. See
   8 the file Tech.Notes for some information on the internals.
   9
  10 Written by: Philip Hazel <ph10@cam.ac.uk>
  11
  12            Copyright (c) 1997-2003 University of Cambridge
  13
  14 -----------------------------------------------------------------------------
  15 Redistribution and use in source and binary forms, with or without
  16 modification, are permitted provided that the following conditions are met:
  17
  18     * Redistributions of source code must retain the above copyright notice,
  19       this list of conditions and the following disclaimer.
  20
  21     * Redistributions in binary form must reproduce the above copyright
  22       notice, this list of conditions and the following disclaimer in the
  23       documentation and/or other materials provided with the distribution.
  24
  25     * Neither the name of the University of Cambridge nor the names of its
  26       contributors may be used to endorse or promote products derived from
  27       this software without specific prior written permission.
  28
  29 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  30 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  33 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  34 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  35 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  36 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  37 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  38 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  39 POSSIBILITY OF SUCH DAMAGE.
  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 /* Include the internals header, which itself includes Standard C headers plus
  49 the external pcre header. */
  50
  51 #include "internal.h"
  52
  53
  54 /*************************************************
  55 *           Find number for named string         *
  56 *************************************************/
  57
  58 /* This function is used by the two extraction functions below, as well
  59 as being generally available.
  60
  61 Arguments:
  62   code        the compiled regex
  63   stringname  the name whose number is required
  64
  65 Returns:      the number of the named parentheses, or a negative number
  66                 (PCRE_ERROR_NOSUBSTRING) if not found
  67 */
  68
  69 int
  70 pcre_get_stringnumber(const pcre *code, const char *stringname)
  71 {
  72 int rc;
  73 int entrysize;
  74 int top, bot;
  75 uschar *nametable;
  76
  77 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMECOUNT, &top)) != 0)
  78   return rc;
  79 if (top <= 0) return PCRE_ERROR_NOSUBSTRING;
  80
  81 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMEENTRYSIZE, &entrysize)) != 0)
  82   return rc;
  83 if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMETABLE, &nametable)) != 0)
  84   return rc;
  85
  86 bot = 0;
  87 while (top > bot)
  88   {
  89   int mid = (top + bot) / 2;
  90   uschar *entry = nametable + entrysize*mid;
  91   int c = strcmp(stringname, (char *)(entry + 2));
  92   if (c == 0) return (entry[0] << 8) + entry[1];
  93   if (c > 0) bot = mid + 1; else top = mid;
  94   }
  95
  96 return PCRE_ERROR_NOSUBSTRING;
  97 }
  98
  99
 100
 101 /*************************************************
 102 *      Copy captured string to given buffer      *
 103 *************************************************/
 104
 105 /* This function copies a single captured substring into a given buffer.
 106 Note that we use memcpy() rather than strncpy() in case there are binary zeros
 107 in the string.
 108
 109 Arguments:
 110   subject        the subject string that was matched
 111   ovector        pointer to the offsets table
 112   stringcount    the number of substrings that were captured
 113                    (i.e. the yield of the pcre_exec call, unless
 114                    that was zero, in which case it should be 1/3
 115                    of the offset table size)
 116   stringnumber   the number of the required substring
 117   buffer         where to put the substring
 118   size           the size of the buffer
 119
 120 Returns:         if successful:
 121                    the length of the copied string, not including the zero
 122                    that is put on the end; can be zero
 123                  if not successful:
 124                    PCRE_ERROR_NOMEMORY (-6) buffer too small
 125                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 126 */
 127
 128 int
 129 pcre_copy_substring(const char *subject, int *ovector, int stringcount,
 130   int stringnumber, char *buffer, int size)
 131 {
 132 int yield;
 133 if (stringnumber < 0 || stringnumber >= stringcount)
 134   return PCRE_ERROR_NOSUBSTRING;
 135 stringnumber *= 2;
 136 yield = ovector[stringnumber+1] - ovector[stringnumber];
 137 if (size < yield + 1) return PCRE_ERROR_NOMEMORY;
 138 memcpy(buffer, subject + ovector[stringnumber], yield);
 139 buffer[yield] = 0;
 140 return yield;
 141 }
 142
 143
 144
 145 /*************************************************
 146 *   Copy named captured string to given buffer   *
 147 *************************************************/
 148
 149 /* This function copies a single captured substring into a given buffer,
 150 identifying it by name.
 151
 152 Arguments:
 153   code           the compiled regex
 154   subject        the subject string that was matched
 155   ovector        pointer to the offsets table
 156   stringcount    the number of substrings that were captured
 157                    (i.e. the yield of the pcre_exec call, unless
 158                    that was zero, in which case it should be 1/3
 159                    of the offset table size)
 160   stringname     the name of the required substring
 161   buffer         where to put the substring
 162   size           the size of the buffer
 163
 164 Returns:         if successful:
 165                    the length of the copied string, not including the zero
 166                    that is put on the end; can be zero
 167                  if not successful:
 168                    PCRE_ERROR_NOMEMORY (-6) buffer too small
 169                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 170 */
 171
 172 int
 173 pcre_copy_named_substring(const pcre *code, const char *subject, int *ovector,
 174   int stringcount, const char *stringname, char *buffer, int size)
 175 {
 176 int n = pcre_get_stringnumber(code, stringname);
 177 if (n <= 0) return n;
 178 return pcre_copy_substring(subject, ovector, stringcount, n, buffer, size);
 179 }
 180
 181
 182
 183 /*************************************************
 184 *      Copy all captured strings to new store    *
 185 *************************************************/
 186
 187 /* This function gets one chunk of store and builds a list of pointers and all
 188 of the captured substrings in it. A NULL pointer is put on the end of the list.
 189
 190 Arguments:
 191   subject        the subject string that was matched
 192   ovector        pointer to the offsets table
 193   stringcount    the number of substrings that were captured
 194                    (i.e. the yield of the pcre_exec call, unless
 195                    that was zero, in which case it should be 1/3
 196                    of the offset table size)
 197   listptr        set to point to the list of pointers
 198
 199 Returns:         if successful: 0
 200                  if not successful:
 201                    PCRE_ERROR_NOMEMORY (-6) failed to get store
 202 */
 203
 204 int
 205 pcre_get_substring_list(const char *subject, int *ovector, int stringcount,
 206   const char ***listptr)
 207 {
 208 int i;
 209 int size = sizeof(char *);
 210 int double_count = stringcount * 2;
 211 char **stringlist;
 212 char *p;
 213
 214 for (i = 0; i < double_count; i += 2)
 215   size += sizeof(char *) + ovector[i+1] - ovector[i] + 1;
 216
 217 stringlist = (char **)(pcre_malloc)(size);
 218 if (stringlist == NULL) return PCRE_ERROR_NOMEMORY;
 219
 220 *listptr = (const char **)stringlist;
 221 p = (char *)(stringlist + stringcount + 1);
 222
 223 for (i = 0; i < double_count; i += 2)
 224   {
 225   int len = ovector[i+1] - ovector[i];
 226   memcpy(p, subject + ovector[i], len);
 227   *stringlist++ = p;
 228   p += len;
 229   *p++ = 0;
 230   }
 231
 232 *stringlist = NULL;
 233 return 0;
 234 }
 235
 236
 237
 238 /*************************************************
 239 *   Free store obtained by get_substring_list    *
 240 *************************************************/
 241
 242 /* This function exists for the benefit of people calling PCRE from non-C
 243 programs that can call its functions, but not free() or (pcre_free)() directly.
 244
 245 Argument:   the result of a previous pcre_get_substring_list()
 246 Returns:    nothing
 247 */
 248
 249 void
 250 pcre_free_substring_list(const char **pointer)
 251 {
 252 (pcre_free)((void *)pointer);
 253 }
 254
 255
 256
 257 /*************************************************
 258 *      Copy captured string to new store         *
 259 *************************************************/
 260
 261 /* This function copies a single captured substring into a piece of new
 262 store
 263
 264 Arguments:
 265   subject        the subject string that was matched
 266   ovector        pointer to the offsets table
 267   stringcount    the number of substrings that were captured
 268                    (i.e. the yield of the pcre_exec call, unless
 269                    that was zero, in which case it should be 1/3
 270                    of the offset table size)
 271   stringnumber   the number of the required substring
 272   stringptr      where to put a pointer to the substring
 273
 274 Returns:         if successful:
 275                    the length of the string, not including the zero that
 276                    is put on the end; can be zero
 277                  if not successful:
 278                    PCRE_ERROR_NOMEMORY (-6) failed to get store
 279                    PCRE_ERROR_NOSUBSTRING (-7) substring not present
 280 */
 281
 282 int
 283 pcre_get_substring(const char *subject, int *ovector, int stringcount,
 284   int stringnumber, const char **stringptr)
 285 {
 286 int yield;
 287 char *substring;
 288 if (stringnumber < 0 || stringnumber >= stringcount)
 289   return PCRE_ERROR_NOSUBSTRING;
 290 stringnumber *= 2;
 291 yield = ovector[stringnumber+1] - ovector[stringnumber];
 292 substring = (char *)(pcre_malloc)(yield + 1);
 293 if (substring == NULL) return PCRE_ERROR_NOMEMORY;
 294 memcpy(substring, subject + ovector[stringnumber], yield);
 295 substring[yield] = 0;
 296 *stringptr = substring;
 297 return yield;
 298 }
 299
 300
 301
 302 /*************************************************
 303 *   Copy named captured string to new store      *
 304 *************************************************/
 305
 306 /* This function copies a single captured substring, identified by name, into
 307 new store.
 308
 309 Arguments:
 310   code           the compiled regex
 311   subject        the subject string that was matched
 312   ovector        pointer to the offsets table
 313   stringcount    the number of substrings that were captured
 314                    (i.e. the yield of the pcre_exec call, unless
 315                    that was zero, in which case it should be 1/3
 316                    of the offset table size)
 317   stringname     the name of the required substring
 318   stringptr      where to put the pointer
 319
 320 Returns:         if successful:
 321                    the length of the copied string, not including the zero
 322                    that is put on the end; can be zero
 323                  if not successful:
 324                    PCRE_ERROR_NOMEMORY (-6) couldn't get memory
 325                    PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
 326 */
 327
 328 int
 329 pcre_get_named_substring(const pcre *code, const char *subject, int *ovector,
 330   int stringcount, const char *stringname, const char **stringptr)
 331 {
 332 int n = pcre_get_stringnumber(code, stringname);
 333 if (n <= 0) return n;
 334 return pcre_get_substring(subject, ovector, stringcount, n, stringptr);
 335 }
 336
 337
 338
 339
 340 /*************************************************
 341 *       Free store obtained by get_substring     *
 342 *************************************************/
 343
 344 /* This function exists for the benefit of people calling PCRE from non-C
 345 programs that can call its functions, but not free() or (pcre_free)() directly.
 346
 347 Argument:   the result of a previous pcre_get_substring()
 348 Returns:    nothing
 349 */
 350
 351 void
 352 pcre_free_substring(const char *pointer)
 353 {
 354 (pcre_free)((void *)pointer);
 355 }
 356
 357 /* End of get.c */