PHP Decode

<?  class ID3TagsReader { 
    var $aTV23 = array( // array of possible sys tags (for last version of ID3) 
        'TIT2', 
        'TALB', 
        'TPE1', 
        'TPE2', 
        'TRCK', 
        'TYER', 
        'TLEN', 
        'USLT', 
        'TPOS', 
        'TCON', 
        'TENC', 
        'TCOP', 
        'TPUB', 
        'TOPE', 
        'WXXX', 
        'COMM', 
        'TCOM' 
    ); 
    var $aTV23t = array( // array of titles for sys tags 
        'Title', 
        'Album', 
        'Author', 
        'AlbumAuthor', 
        'Track', 
        'Year', 
        'Lenght', 
        'Lyric', 
        'Desc', 
        'Genre', 
        'Encoded', 
        'Copyright', 
        'Publisher', 
        'OriginalArtist', 
        'URL', 
        'Comments', 
        'Composer' 
    ); 
    var $aTV22 = array( // array of possible sys tags (for old version of ID3) 
        'TT2', 
        'TAL', 
        'TP1', 
        'TRK', 
        'TYE', 
        'TLE', 
        'ULT' 
    ); 
    var $aTV22t = array( // array of titles for sys tags 
        'Title', 
        'Album', 
        'Author', 
        'Track', 
        'Year', 
        'Lenght', 
        'Lyric' 
    ); 
    // constructor 
    function ID3TagsReader() {} 
    // functions 
    function getTagsInfo($sFilepath) 
    { 
        // read source file 
        $iFSize = filesize($sFilepath); 
        $vFD = fopen($sFilepath, 'r'); 
        $sSrc = fread($vFD, $iFSize); 
        fclose($vFD); 
        // obtain base info 
        if (substr($sSrc, 0, 3) == 'ID3') { 
            $aInfo['FileName'] = $sFilepath; 
            $aInfo['Version'] = hexdec(bin2hex(substr($sSrc, 3, 1))). 
            '.'.hexdec(bin2hex(substr($sSrc, 4, 1))); 
        } 
        // passing through possible tags of idv2 (v3 and v4) 
        if ($aInfo['Version'] == '4.0' || $aInfo['Version'] == '3.0')  
        { 
            for ($i = 0; $i < count($this->aTV23); $i++) 
            { 
                if (strpos($sSrc, $this->aTV23[$i].chr(0)) != FALSE) 
                { 
                    $s = ''; 
                    $iPos = strpos($sSrc, $this - > aTV23[$i].chr(0)); 
                    $iLen = hexdec(bin2hex(substr($sSrc, ($iPos + 5), 3))); 
                    $data = substr($sSrc, $iPos, 9 + $iLen); 
                    for ($a = 0; $a < strlen($data); $a++)  
                    { 
                        $char = substr($data, $a, 1); 
                        if ($char >= ' ' && $char <= '~') 
                            $s. = $char; 
                    } 
                    if (substr($s, 0, 4) == $this->aTV23[$i])  
                    { 
                        $iSL = 4; 
                        if ($this->aTV23[$i] == 'USLT') { 
                            $iSL = 7; 
                        } 
                        elseif($this->aTV23[$i] == 'TALB') { 
                            $iSL = 5; 
                        } 
                        elseif($this->aTV23[$i] == 'TENC') { 
                            $iSL = 6; 
                        } 
                        $aInfo[$this->aTV23t[$i]] = substr($s, $iSL); 
                    } 
                } 
            } 
        } 
        // passing through possible tags of idv2 (v2) 
        if ($aInfo['Version'] == '2.0') 
        { 
            for ($i = 0; $i < count($this->aTV22); $i++)  
            { 
                if (strpos($sSrc, $this->aTV22[$i].chr(0)) != FALSE)  
               	{ 
                    $s = ''; 
                    $iPos = strpos($sSrc, $this->aTV22[$i].chr(0)); 
                    $iLen = hexdec(bin2hex(substr($sSrc, ($iPos + 3), 3))); 
                    $data = substr($sSrc, $iPos, 6+ $iLen); 
                    for ($a = 0; $a < strlen($data); $a++)  
                    { 
                        $char = substr($data, $a, 1); 
                        if ($char >= ' ' && $char <= '~') 
                            $s. = $char; 
                    } 
                    if (substr($s, 0, 3) == $this - > aTV22[$i])  
                    { 
                        $iSL = 3; 
                        if ($this - > aTV22[$i] == 'ULT') { 
                            $iSL = 6; 
                        } 
                        $aInfo[$this - > aTV22t[$i]] = substr($s, $iSL); 
                    } 
                } 
            } 
        } 
        return $aInfo; 
    } 
} ?>