zoneminder/src/zm_regexp.cpp

/*
 * ZoneMinder regular expression class implementation, $Date$, $Revision$
 * Copyright (C) 2003, 2004, 2005, 2006  Philip Coombes
 * 
 * This program 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.
 * 
 * This program 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.
*/ 

#include <string.h>

#include "zm.h"
#include "zm_regexp.h"

#if HAVE_LIBPCRE

RegExpr::RegExpr( const char *pattern, int flags, int p_max_matches ) : max_matches( p_max_matches ), match_buffers( 0 ), match_lengths( 0 ), match_valid( 0 )
{
	const char *errstr;
	int erroffset = 0;
	if ( !(regex = pcre_compile( pattern, flags, &errstr, &erroffset, 0 )) )
	{
		Fatal( "pcre_compile(%s): %s at %d", pattern, errstr, erroffset );
	}

	regextra = pcre_study( regex, 0, &errstr );
	if ( errstr )
	{
		Fatal( "pcre_study(%s): %s", pattern, errstr );
	}

	if ( ok = (bool)regex )
	{
		match_vectors = new int[3*max_matches];
		memset( match_vectors, 0, sizeof(*match_vectors)*3*max_matches );
		match_buffers = new char *[max_matches];
		memset( match_buffers, 0, sizeof(*match_buffers)*max_matches );
		match_lengths = new int[max_matches];
		memset( match_lengths, 0, sizeof(*match_lengths)*max_matches );
		match_valid = new bool[max_matches];
		memset( match_valid, 0, sizeof(*match_valid)*max_matches );
	}
	n_matches = 0;
}

RegExpr::~RegExpr()
{
	for ( int i = 0; i < max_matches; i++ )
	{
		if ( match_buffers[i] )
		{
			delete[] match_buffers[i];
		}
	}
	delete[] match_valid;
	delete[] match_lengths;
	delete[] match_buffers;
	delete[] match_vectors;
}

int RegExpr::Match( const char *subject_string, int subject_length, int flags )
{
	match_string = subject_string;

	n_matches = pcre_exec( regex, regextra, subject_string, subject_length, 0, flags, match_vectors, 2*max_matches );

	if ( n_matches <= 0 )
	{
		if ( n_matches < PCRE_ERROR_NOMATCH )
		{
			Error( "Error %d executing regular expression", n_matches );
		}
		return( n_matches = 0 );
	}

	for( int i = 0; i < max_matches; i++ )
	{
		match_valid[i] = false;
	}
	return( n_matches );
}

const char *RegExpr::MatchString( int match_index ) const
{
	if ( match_index > n_matches )
	{
		return( 0 );
	}
	if ( !match_valid[match_index] )
	{
		int match_len = match_vectors[(2*match_index)+1]-match_vectors[2*match_index];
		if ( match_lengths[match_index] < (match_len+1) )
		{
			delete[] match_buffers[match_index];
			match_buffers[match_index] = new char[match_len+1];
			match_lengths[match_index] = match_len+1;
		}
		memcpy( match_buffers[match_index], match_string+match_vectors[2*match_index], match_len );
		match_buffers[match_index][match_len] = '\0';
		match_valid[match_index] = true;
	}
	return( match_buffers[match_index] );
}

int RegExpr::MatchLength( int match_index ) const
{
	if ( match_index > n_matches )
	{
		return( 0 );
	}
	return( match_vectors[(2*match_index)+1]-match_vectors[2*match_index] );
}

#endif // HAVE_LIBPCRE