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350 lines
11 KiB
C
350 lines
11 KiB
C
/*************************************************
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* Perl-Compatible Regular Expressions *
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*************************************************/
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/*
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This is a library of functions to support regular expressions whose syntax
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and semantics are as close as possible to those of the Perl 5 language. See
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the file Tech.Notes for some information on the internals.
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Written by: Philip Hazel <ph10@cam.ac.uk>
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Copyright (c) 1997-2003 University of Cambridge
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-----------------------------------------------------------------------------
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Permission is granted to anyone to use this software for any purpose on any
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computer system, and to redistribute it freely, subject to the following
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restrictions:
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1. This software is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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2. The origin of this software must not be misrepresented, either by
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explicit claim or by omission.
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3. Altered versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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4. If PCRE is embedded in any software that is released under the GNU
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General Purpose Licence (GPL), then the terms of that licence shall
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supersede any condition above with which it is incompatible.
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-----------------------------------------------------------------------------
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*/
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/* This module contains some convenience functions for extracting substrings
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from the subject string after a regex match has succeeded. The original idea
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for these functions came from Scott Wimer <scottw@cgibuilder.com>. */
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/* Include the internals header, which itself includes Standard C headers plus
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the external pcre header. */
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#include "internal.h"
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/*************************************************
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* Find number for named string *
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*************************************************/
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/* This function is used by the two extraction functions below, as well
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as being generally available.
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Arguments:
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code the compiled regex
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stringname the name whose number is required
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Returns: the number of the named parentheses, or a negative number
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(PCRE_ERROR_NOSUBSTRING) if not found
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*/
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int
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pcre_get_stringnumber(const pcre *code, const char *stringname)
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{
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int rc;
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int entrysize;
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int top, bot;
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uschar *nametable;
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if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMECOUNT, &top)) != 0)
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return rc;
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if (top <= 0) return PCRE_ERROR_NOSUBSTRING;
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if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMEENTRYSIZE, &entrysize)) != 0)
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return rc;
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if ((rc = pcre_fullinfo(code, NULL, PCRE_INFO_NAMETABLE, &nametable)) != 0)
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return rc;
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bot = 0;
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while (top > bot)
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{
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int mid = (top + bot) / 2;
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uschar *entry = nametable + entrysize*mid;
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int c = strcmp(stringname, (char *)(entry + 2));
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if (c == 0) return (entry[0] << 8) + entry[1];
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if (c > 0) bot = mid + 1; else top = mid;
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}
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return PCRE_ERROR_NOSUBSTRING;
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}
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/*************************************************
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* Copy captured string to given buffer *
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*************************************************/
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/* This function copies a single captured substring into a given buffer.
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Note that we use memcpy() rather than strncpy() in case there are binary zeros
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in the string.
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Arguments:
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subject the subject string that was matched
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ovector pointer to the offsets table
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stringcount the number of substrings that were captured
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(i.e. the yield of the pcre_exec call, unless
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that was zero, in which case it should be 1/3
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of the offset table size)
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stringnumber the number of the required substring
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buffer where to put the substring
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size the size of the buffer
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Returns: if successful:
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the length of the copied string, not including the zero
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that is put on the end; can be zero
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if not successful:
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PCRE_ERROR_NOMEMORY (-6) buffer too small
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PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
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*/
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int
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pcre_copy_substring(const char *subject, int *ovector, int stringcount,
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int stringnumber, char *buffer, int size)
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{
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int yield;
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if (stringnumber < 0 || stringnumber >= stringcount)
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return PCRE_ERROR_NOSUBSTRING;
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stringnumber *= 2;
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yield = ovector[stringnumber+1] - ovector[stringnumber];
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if (size < yield + 1) return PCRE_ERROR_NOMEMORY;
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memcpy(buffer, subject + ovector[stringnumber], yield);
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buffer[yield] = 0;
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return yield;
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}
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/*************************************************
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* Copy named captured string to given buffer *
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*************************************************/
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/* This function copies a single captured substring into a given buffer,
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identifying it by name.
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Arguments:
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code the compiled regex
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subject the subject string that was matched
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ovector pointer to the offsets table
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stringcount the number of substrings that were captured
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(i.e. the yield of the pcre_exec call, unless
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that was zero, in which case it should be 1/3
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of the offset table size)
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stringname the name of the required substring
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buffer where to put the substring
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size the size of the buffer
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Returns: if successful:
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the length of the copied string, not including the zero
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that is put on the end; can be zero
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if not successful:
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PCRE_ERROR_NOMEMORY (-6) buffer too small
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PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
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*/
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int
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pcre_copy_named_substring(const pcre *code, const char *subject, int *ovector,
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int stringcount, const char *stringname, char *buffer, int size)
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{
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int n = pcre_get_stringnumber(code, stringname);
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if (n <= 0) return n;
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return pcre_copy_substring(subject, ovector, stringcount, n, buffer, size);
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}
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/*************************************************
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* Copy all captured strings to new store *
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*************************************************/
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/* This function gets one chunk of store and builds a list of pointers and all
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of the captured substrings in it. A NULL pointer is put on the end of the list.
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Arguments:
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subject the subject string that was matched
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ovector pointer to the offsets table
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stringcount the number of substrings that were captured
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(i.e. the yield of the pcre_exec call, unless
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that was zero, in which case it should be 1/3
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of the offset table size)
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listptr set to point to the list of pointers
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Returns: if successful: 0
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if not successful:
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PCRE_ERROR_NOMEMORY (-6) failed to get store
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*/
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int
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pcre_get_substring_list(const char *subject, int *ovector, int stringcount,
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const char ***listptr)
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{
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int i;
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int size = sizeof(char *);
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int double_count = stringcount * 2;
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char **stringlist;
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char *p;
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for (i = 0; i < double_count; i += 2)
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size += sizeof(char *) + ovector[i+1] - ovector[i] + 1;
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stringlist = (char **)(pcre_malloc)(size);
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if (stringlist == NULL) return PCRE_ERROR_NOMEMORY;
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*listptr = (const char **)stringlist;
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p = (char *)(stringlist + stringcount + 1);
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for (i = 0; i < double_count; i += 2)
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{
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int len = ovector[i+1] - ovector[i];
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memcpy(p, subject + ovector[i], len);
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*stringlist++ = p;
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p += len;
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*p++ = 0;
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}
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*stringlist = NULL;
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return 0;
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}
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/*************************************************
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* Free store obtained by get_substring_list *
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*************************************************/
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/* This function exists for the benefit of people calling PCRE from non-C
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programs that can call its functions, but not free() or (pcre_free)() directly.
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Argument: the result of a previous pcre_get_substring_list()
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Returns: nothing
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*/
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void
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pcre_free_substring_list(const char **pointer)
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{
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(pcre_free)((void *)pointer);
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}
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/*************************************************
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* Copy captured string to new store *
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*************************************************/
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/* This function copies a single captured substring into a piece of new
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store
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Arguments:
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subject the subject string that was matched
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ovector pointer to the offsets table
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stringcount the number of substrings that were captured
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(i.e. the yield of the pcre_exec call, unless
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that was zero, in which case it should be 1/3
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of the offset table size)
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stringnumber the number of the required substring
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stringptr where to put a pointer to the substring
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Returns: if successful:
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the length of the string, not including the zero that
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is put on the end; can be zero
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if not successful:
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PCRE_ERROR_NOMEMORY (-6) failed to get store
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PCRE_ERROR_NOSUBSTRING (-7) substring not present
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*/
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int
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pcre_get_substring(const char *subject, int *ovector, int stringcount,
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int stringnumber, const char **stringptr)
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{
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int yield;
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char *substring;
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if (stringnumber < 0 || stringnumber >= stringcount)
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return PCRE_ERROR_NOSUBSTRING;
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stringnumber *= 2;
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yield = ovector[stringnumber+1] - ovector[stringnumber];
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substring = (char *)(pcre_malloc)(yield + 1);
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if (substring == NULL) return PCRE_ERROR_NOMEMORY;
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memcpy(substring, subject + ovector[stringnumber], yield);
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substring[yield] = 0;
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*stringptr = substring;
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return yield;
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}
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/*************************************************
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* Copy named captured string to new store *
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*************************************************/
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/* This function copies a single captured substring, identified by name, into
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new store.
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Arguments:
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code the compiled regex
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subject the subject string that was matched
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ovector pointer to the offsets table
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stringcount the number of substrings that were captured
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(i.e. the yield of the pcre_exec call, unless
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that was zero, in which case it should be 1/3
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of the offset table size)
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stringname the name of the required substring
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stringptr where to put the pointer
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Returns: if successful:
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the length of the copied string, not including the zero
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that is put on the end; can be zero
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if not successful:
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PCRE_ERROR_NOMEMORY (-6) couldn't get memory
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PCRE_ERROR_NOSUBSTRING (-7) no such captured substring
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*/
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int
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pcre_get_named_substring(const pcre *code, const char *subject, int *ovector,
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int stringcount, const char *stringname, const char **stringptr)
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{
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int n = pcre_get_stringnumber(code, stringname);
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if (n <= 0) return n;
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return pcre_get_substring(subject, ovector, stringcount, n, stringptr);
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}
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/*************************************************
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* Free store obtained by get_substring *
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*************************************************/
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/* This function exists for the benefit of people calling PCRE from non-C
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programs that can call its functions, but not free() or (pcre_free)() directly.
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Argument: the result of a previous pcre_get_substring()
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Returns: nothing
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*/
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void
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pcre_free_substring(const char *pointer)
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{
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(pcre_free)((void *)pointer);
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}
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/* End of get.c */
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