regexp.c

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/*
 * $Id: regexp.c 4518 2008-07-28 15:39:28Z henningw $
 *
 * Regular expression functions
 *
 * Copyright (C) 2003 Juha Heinanen
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/*!
 * \file 
 * \brief Regular Expression functions
 */

#include <sys/types.h>
#include <string.h>
#include <regex.h>
#include <ctype.h>
#include "regexp.h"
#include "dprint.h"

/*! \brief Replace in replacement tokens \\d with substrings of string pointed by
 * pmatch.
 */
int replace(regmatch_t* pmatch, char* string, char* replacement, str* result)
{
   int len, i, j, digit, size;

   len = strlen(replacement);
   j = 0;

   for (i = 0; i < len; i++) {
      if (replacement[i] == '\\') {
         if (i < len - 1) {
            if (isdigit((unsigned char)replacement[i+1])) {
               digit = replacement[i+1] - '0';
               if (pmatch[digit].rm_so != -1) {
                  size = pmatch[digit].rm_eo - pmatch[digit].rm_so;
                  if (j + size < result->len) {
                     memcpy(&(result->s[j]), string+pmatch[digit].rm_so, size);
                     j = j + size;
                  } else {
                     return -1;
                  }
               } else {
                  return -2;
               }
               i = i + 1;
               continue;
            } else {
               i = i + 1;
            }
         } else {
            return -3;
         }
      }
      if (j + 1 < result->len) {
         result->s[j] = replacement[i];
         j = j + 1;
      } else {
         return -4;
      }
   }
   result->len = j;
   return 1;
}


/*! \brief Match pattern against string and store result in pmatch */
int reg_match(char *pattern, char *string, regmatch_t *pmatch)
{
   regex_t preg;

   if (regcomp(&preg, pattern, REG_EXTENDED | REG_NEWLINE)) {
      return -1;
   }
   if (preg.re_nsub > MAX_MATCH) {
      regfree(&preg);
      return -2;
   }
   if (regexec(&preg, string, MAX_MATCH, pmatch, 0)) {
      regfree(&preg);
      return -3;
   }
   regfree(&preg);
   return 0;
}


/*! \brief Match pattern against string and, if match succeeds, and replace string
 * with replacement substituting tokens \\d with matched substrings.
 */
int reg_replace(char *pattern, char *replacement, char *string, str *result)
{
   regmatch_t pmatch[MAX_MATCH];

   LM_DBG("pattern: '%s', replacement: '%s', string: '%s'\n",
       pattern, replacement, string);

   if (reg_match(pattern, string, &(pmatch[0]))) {
      return -1;
   }

   return replace(&pmatch[0], string, replacement, result);

}

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