PHP create ZIP Archive function

zip.php

<?php
/* creates a compressed zip file */
function create_zip($files = array(), $destination = '', $overwrite = false) {
	//if the zip file already exists and overwrite is false, return false
	if(file_exists($destination) && !$overwrite) { return false; }
	//vars
	$valid_files = array();
	//if files were passed in...
	if(is_array($files)) {
		//cycle through each file
		foreach($files as $path => $filename) {
			//make sure the file exists
			if(file_exists($path.$filename)) {
				$valid_files[$path] = $filename;
			}
		}
	}
	//if we have good files...
	if(count($valid_files)) {
		//create the archive
		$zip = new ZipArchive();
		if($zip->open($destination, $overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true) {
			return false;
		}
		//add the files
		foreach($valid_files as $path => $filename) {
			$zip->addFile($path.$filename, $filename);
		}
		//debug
		//return ('The zip archive contains '.$zip->numFiles.' files with a status of '.$zip->status);		
		//close the zip -- done!
		$zip->close();		
		//check to make sure the file exists
		return file_exists($destination);
	}else{
		return false;
	}
}
?>