php 文件Zip压缩

// php 文件Zip压缩
function create_zip($files = array(), $destination ="", $overwrite = false) {
    if(file_exists($destination) && !$overwrite)
        return false;
    if(is_array($files)) {
        foreach($files as $file) {
            if(file_exists($file))
                $valid_files[] = $file;
        }
    }
    if(count($valid_files)) {
        $zip = new ZipArchive();
        if($zip->open($destination,$overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true)
            return false;
        foreach($valid_files as $file)
            $zip->addFile($file,$file);
        $zip->close();
        return file_exists($destination);
    }else
    return false;
}
$files=array("a.gif", "b.gif", "c.gif");
create_zip($files, "myzipfile.zip", true);