/************************************************* * 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) 1997-2003 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 "pcre_internal.h" /* @func pcre_get_stringnumber ************************************************ ** ** Find number for named string ** ** This function is used by the two extraction functions below, as well ** as being generally available. ** ** @param [r] code [const pcre*] the compiled regex ** @param [r] stringname [const char*] the name whose number is required ** @return [int] the number of the named parentheses, or a negative number ** (PCRE_ERROR_NOSUBSTRING) if not found ******************************************************************************/ int pcre_get_stringnumber(const pcre *code, const char *stringname) { int rc; int entrysize; int top, bot; uschar *nametable; if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMECOUNT, &top)) != 0) return rc; if (top <= 0) return PCRE_ERROR_NOSUBSTRING; if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMEENTRYSIZE, &entrysize)) != 0) return rc; if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMETABLE, &nametable)) != 0) return rc; bot = 0; while (top > bot) { int mid = (top + bot) / 2; uschar *entry = nametable + entrysize*mid; int c = strcmp(stringname, (char *)(entry + 2)); if (c == 0) return (entry[0] << 8) + entry[1]; if (c > 0) bot = mid + 1; else top = mid; } return PCRE_ERROR_NOSUBSTRING; } /* @func pcre_copy_substring ************************************************** ** ** 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. ** ** @param [r] subject [const char*] the subject string that was matched ** @param [r] ovector [const int*] pointer to the offsets table ** @param [r] stringcount [int] 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) ** @param [r] stringnumber [int] the number of the required substring ** @param [w] buffer [char*] where to put the substring ** @param [r] size [int] the size of the buffer ** @return [int] 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, const 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; } /* @func pcre_copy_named_substring********************************************* ** ** Copy named captured string to given buffer ** ** This function copies a single captured substring into a given buffer, ** identifying it by name. ** ** @param [r] code [const pcre*] the compiled regex ** @param [r] subject [const char*] the subject string that was matched ** @param [r] ovector [const int*] pointer to the offsets table ** @param [r] stringcount [int] 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) ** @param [r] stringname [const char*] the name of the required substring ** @param [w] buffer [char*] where to put the substring ** @param [r] size [int] the size of the buffer ** @return [int] 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_named_substring(const pcre *code, const char *subject, const int *ovector, int stringcount, const char *stringname, char *buffer, int size) { int n = pcre_get_stringnumber(code, stringname); if (n <= 0) return n; return pcre_copy_substring(subject, ovector, stringcount, n, buffer, size); } /* @func pcre_get_substring_list ********************************************** ** ** 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. ** ** @param [r] subject [const char*] the subject string that was matched ** @param [w] ovector [const int*] pointer to the offsets table ** @param [r] stringcount [int] 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) ** @param [r] listptr [const char***] set to point to the list of pointers ** @return [int] if successful: 0 ** if not successful: ** PCRE_ERROR_NOMEMORY (-6) failed to get store ******************************************************************************/ int pcre_get_substring_list(const char *subject, const 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; } /* @func pcre_free_substring_list ********************************************* ** ** 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. ** @param [r] pointer [const char**] the result of a previous ** pcre_get_substring_list() ** @return [void] ******************************************************************************/ void pcre_free_substring_list(const char **pointer) { (pcre_free)((void *)pointer); } /* @func pcre_get_substring *************************************************** ** ** Copy captured string to new store ** ** This function copies a single captured substring into a piece of new ** store ** ** @param [r] subject [const char*] the subject string that was matched ** @param [r] ovector [const int*] pointer to the offsets table ** @param [r] stringcount [int] 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) ** @param [r] stringnumber [int] the number of the required substring ** @param [w] stringptr [const char**] where to put a pointer to the substring ** @return [int] 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, const 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; } /* @func pcre_get_named_substring ********************************************* ** ** Copy named captured string to new store ** ** This function copies a single captured substring, identified by name, into ** new store. ** ** @param [r] code [const pcre*] the compiled regex ** @param [r] subject [const char*] the subject string that was matched ** @param [r] ovector [const int*] pointer to the offsets table ** @param [r] stringcount [int] 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) ** @param [r] stringname [const char*] the name of the required substring ** @param [w] stringptr [const char**] where to put the pointer ** @return [int] 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) couldn't get memory ** PCRE_ERROR_NOSUBSTRING (-7) no such captured substring ******************************************************************************/ int pcre_get_named_substring(const pcre *code, const char *subject, const int *ovector, int stringcount, const char *stringname, const char **stringptr) { int n = pcre_get_stringnumber(code, stringname); if (n <= 0) return n; return pcre_get_substring(subject, ovector, stringcount, n, stringptr); } /* @func pcre_free_substring ************************************************** ** ** 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. ** ** @param [d] pointer [const char**] the result of a previous ** pcre_get_substring() ** @return [void] ******************************************************************************/ void pcre_free_substring(const char **pointer) { (pcre_free)((void *)*pointer); } /* End of get.c */