/************************************************* * Perl-Compatible Regular Expressions * *************************************************/ /* This is a library of functions to support regular expressions whose syntax and semantics are as close as possible to those of the Perl 5 language. See the file Tech.Notes for some information on the internals. Written by: Philip Hazel Copyright (c) 1997-2000 University of Cambridge ----------------------------------------------------------------------------- Permission is granted to anyone to use this software for any purpose on any computer system, and to redistribute it freely, subject to the following restrictions: 1. This software 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. 2. The origin of this software must not be misrepresented, either by explicit claim or by omission. 3. Altered versions must be plainly marked as such, and must not be misrepresented as being the original software. 4. If PCRE is embedded in any software that is released under the GNU General Purpose Licence (GPL), then the terms of that licence shall supersede any condition above with which it is incompatible. ----------------------------------------------------------------------------- */ /* This module contains some convenience functions for extracting substrings from the subject string after a regex match has succeeded. The original idea for these functions came from Scott Wimer . */ /* Include the internals header, which itself includes Standard C headers plus the external pcre header. */ #include "internal.h" /************************************************* * Copy captured string to given buffer * *************************************************/ /* This function copies a single captured substring into a given buffer. Note that we use memcpy() rather than strncpy() in case there are binary zeros in the string. Arguments: subject the subject string that was matched ovector pointer to the offsets table stringcount the number of substrings that were captured (i.e. the yield of the pcre_exec call, unless that was zero, in which case it should be 1/3 of the offset table size) stringnumber the number of the required substring buffer where to put the substring size the size of the buffer Returns: if successful: the length of the copied string, not including the zero that is put on the end; can be zero if not successful: PCRE_ERROR_NOMEMORY (-6) buffer too small PCRE_ERROR_NOSUBSTRING (-7) no such captured substring */ int pcre_copy_substring(const char *subject, int *ovector, int stringcount, int stringnumber, char *buffer, int size) { int yield; if (stringnumber < 0 || stringnumber >= stringcount) return PCRE_ERROR_NOSUBSTRING; stringnumber *= 2; yield = ovector[stringnumber+1] - ovector[stringnumber]; if (size < yield + 1) return PCRE_ERROR_NOMEMORY; memcpy(buffer, subject + ovector[stringnumber], yield); buffer[yield] = 0; return yield; } /************************************************* * Copy all captured strings to new store * *************************************************/ /* This function gets one chunk of store and builds a list of pointers and all of the captured substrings in it. A NULL pointer is put on the end of the list. Arguments: subject the subject string that was matched ovector pointer to the offsets table stringcount the number of substrings that were captured (i.e. the yield of the pcre_exec call, unless that was zero, in which case it should be 1/3 of the offset table size) listptr set to point to the list of pointers Returns: if successful: 0 if not successful: PCRE_ERROR_NOMEMORY (-6) failed to get store */ int pcre_get_substring_list(const char *subject, int *ovector, int stringcount, const char ***listptr) { int i; int size = sizeof(char *); int double_count = stringcount * 2; char **stringlist; char *p; for (i = 0; i < double_count; i += 2) size += sizeof(char *) + ovector[i+1] - ovector[i] + 1; stringlist = (char **)(pcre_malloc)(size); if (stringlist == NULL) return PCRE_ERROR_NOMEMORY; *listptr = (const char **)stringlist; p = (char *)(stringlist + stringcount + 1); for (i = 0; i < double_count; i += 2) { int len = ovector[i+1] - ovector[i]; memcpy(p, subject + ovector[i], len); *stringlist++ = p; p += len; *p++ = 0; } *stringlist = NULL; return 0; } /************************************************* * Free store obtained by get_substring_list * *************************************************/ /* This function exists for the benefit of people calling PCRE from non-C programs that can call its functions, but not free() or (pcre_free)() directly. Argument: the result of a previous pcre_get_substring_list() Returns: nothing */ void pcre_free_substring_list(const char **pointer) { (pcre_free)((void *)pointer); } /************************************************* * Copy captured string to new store * *************************************************/ /* This function copies a single captured substring into a piece of new store Arguments: subject the subject string that was matched ovector pointer to the offsets table stringcount the number of substrings that were captured (i.e. the yield of the pcre_exec call, unless that was zero, in which case it should be 1/3 of the offset table size) stringnumber the number of the required substring stringptr where to put a pointer to the substring Returns: if successful: the length of the string, not including the zero that is put on the end; can be zero if not successful: PCRE_ERROR_NOMEMORY (-6) failed to get store PCRE_ERROR_NOSUBSTRING (-7) substring not present */ int pcre_get_substring(const char *subject, int *ovector, int stringcount, int stringnumber, const char **stringptr) { int yield; char *substring; if (stringnumber < 0 || stringnumber >= stringcount) return PCRE_ERROR_NOSUBSTRING; stringnumber *= 2; yield = ovector[stringnumber+1] - ovector[stringnumber]; substring = (char *)(pcre_malloc)(yield + 1); if (substring == NULL) return PCRE_ERROR_NOMEMORY; memcpy(substring, subject + ovector[stringnumber], yield); substring[yield] = 0; *stringptr = substring; return yield; } /************************************************* * Free store obtained by get_substring * *************************************************/ /* This function exists for the benefit of people calling PCRE from non-C programs that can call its functions, but not free() or (pcre_free)() directly. Argument: the result of a previous pcre_get_substring() Returns: nothing */ void pcre_free_substring(const char *pointer) { (pcre_free)((void *)pointer); } /* End of get.c */