<?php

	/**
	*	$RCSfile: lib.gzVersionControl.php,v $
	*	@author   $Author: Cornelius Bolten $
	*	@version  $Revision: 1.2 $
	*
	*	@description
	*		this is the gz-Version of VersionControl
	*		The sub-class is capable of storing and retrieving the content articles in a 
	*		compressed format using the gzip library, so it can use less database table space.
	*
	*	@see lib.VersionControl.php
	*/

class gzVersionControl extends VersionControl {
	
		/**
		*	class variables
		*/
		var $gzLevel;			// Level of compression
		var $originalSize;		// original size of content article in uncompressed state
		var $compressedSize;	// size of content article in compressed state

	
		/**
		*	gzVersionControl
		*
		*	init-function
		*	@access public
		*	@param	Object	valid database-object
		*	@param	String	valid database-connection-name
		*	@param	String	TableName of VersionTable	
		*	@param	int		compression-level
		*/	
		function gzVersionControl($dbHandle, $dbHandleName, $vc_tablename, $compressionLevel) {
			$this->dbHandle 	=	$dbHandle;
			$this->dbHandleName	=	$dbHandleName;
			$this->vc_tablename	=	$vc_tablename;
			$this->gzLevel		=	$compressionLevel;
		}	
	
		/**
		*	encode
		*		
		*	function zipps and encodes data-record
		*	
		*	@access private
		*	@param	serializedArray
		*	return 	string	encoded array
		*/
		function encode($serialized) {
			$compressed	=	gzcompress($serialized,$this->gzLevel);
			$encArray	=	base64_encode($compressed);
			
			// save sizes
			$this->originalSize = strlen($serialized);
			$this->compressedSize = strlen($encArray);
			return ($encArray);
		}
		
		/**
		*	decode
		*		
		*	function unzips and decodes data-record
		*	@access private
		*	@param	string	encoded array
		*	return 	serialized array
		*/
		function decode($encArray) {
			$decoded	=	base64_decode($encArray);
			$serialized	=	gzuncompress($decoded);
			return ($serialized);
		}	
}

?>