Function msReplaceSubstring

mapstring.c:521–577

------------------------------------------------------------------------------- */ Replace all occurances of old with new in str. */ It is assumed that str was dynamically created using malloc. */ ------------------------------------------------------------------------------- */

/*       It is assumed that str was dynamically created using malloc.              */
/* ------------------------------------------------------------------------------- */
char *msReplaceSubstring(char *str, const char *old, const char *new)
{
      size_t str_len, old_len, new_len, tmp_offset;
      char *tmp_ptr;

      if(new == NULL)
          new = "";

      /*
      ** If old is not found then leave str alone
      */
      if( (tmp_ptr = strstr(str, old)) == NULL)
	return(str);

      /*
      ** Grab some info about incoming strings
      */
      str_len = strlen(str);
      old_len = strlen(old);
      new_len = strlen(new);

      /*
      ** Now loop until old is NOT found in new
      */
      while( tmp_ptr != NULL ) {

	/*
	** re-allocate memory for buf assuming 1 replacement of old with new
        ** don't bother reallocating if old is larger than new)
	*/
        if (old_len < new_len) {
          tmp_offset = tmp_ptr - str;
          str_len = str_len - old_len + new_len;
          str = (char *)msSmallRealloc(str, (str_len + 1)); /* make new space for a copy */
          tmp_ptr = str + tmp_offset;
        }

        /*
        ** Move the trailing part of str to make some room unless old_len == new_len
        */
        if (old_len != new_len) {
            memmove(tmp_ptr+new_len, tmp_ptr+old_len, strlen(tmp_ptr)-old_len+1);
        }

        /*
        ** Now copy new over old
        */
        memcpy(tmp_ptr, new, new_len);

        /*
        ** And look for more matches in the rest of the string
        */
        tmp_ptr = strstr(tmp_ptr + new_len, old);
      }

      return(str);
}