<?php

// I don't have time or interest to write ID3v2 support. BUT I have beta
// code to read ID3v2 tags. If you want to finish this code go for it.
// If you get a good working copy either sent it to me or tell me where to
// redirect people that want it. You can check the _beta_ ID3v2 code at:
// http://leknor.com/code/php/view/beta/class.id3v2.php.txt

// Uncomment the folling define if you want the class to automatically
// read the MPEG frame info to get bitrate, mpeg version, layer, etc.
//
// NOTE: This is needed to maintain pre-version 1.0 behavior which maybe
// needed if you are using info that is from the mpeg frame. This includes
// the length of the song.
//
// This is discouraged because it will siginfincantly lengthen script
// execution time if all you need is the ID3 tag info.
// define('ID3_AUTO_STUDY', true);

// Uncomment the following define if you want tons of debgging info.
// Tip: make sure you use a <PRE> block so the print_r's are readable.
// define('ID3_SHOW_DEBUG', true);

class id3 {
    /*
     * id3 - A Class for reading/writing MP3 ID3 tags
     * 
     * By Sandy McArthur, Jr. <Leknor@Leknor.com>
     * 
     * Copyright 2001 (c) All Rights Reserved, All Responsibility Yours
     *
     * This code is released under the GNU LGPL Go read it over here:
     * http://www.gnu.org/copyleft/lesser.html
     * 
     * I do make one optional request, I would like an account on or a
     * copy of where this code is used. If that is not possible then
     * an email would be cool.
     * 
     * Warning: I really hope this doesn't mess up your MP3s but you
     * are on your own if bad things happen.
     *
     * Note: This code doesn't try to deal with corrupt mp3s. So if you get
     * incorrect length times or something else it may be your mp3. To fix just
     * re-enocde from the CD. :~)
     * 
     * To use this code first create a id3 object passing the path to the mp3 as the first
     * parameter. Then just access the ID3 fields directly (look below for their names).
     * If you want to update a tag just change the fields and then $id3->write();
     * The methods designed for general use are study(), write(), copy($from), remove(),
     * and genres(). Please read the comment before each method for the specifics of each.
     * 
     * eg:
     * 	require_once('class.id3.php');
     *	$id3 = new id3('/path/to/our lady peace - middle of yesterday.mp3');
     *  echo $id3->artists, ' - ', $id3->name;
     *	$id3->comment = 'Go buy some OLP CDs, they rock!';
     *	$id3->write();
     *
     * Change Log:
     *	1.24:	Small change to the write() method because the old way it worked was poorly
     *		thought out. The new write() method has optional parameters. $id3->frameoffset
     *		added which will have the byte offset of the first mpeg frame and $id3->filesize
     *	1.23:	MPEG Frame pasrsion code should be perfect on everything but VBR mp3's.
     *	1.20:	Reimplemented most of the mpeg frame parsing code plus a whole lot more.
     *	1.10:	ID3v1 and v1.1 functionality completed.
     *	1.00:	Decided to rewrite and correct all my poor choices and to implement ID3v1.1
     *		Looking at my old code I'm ashamed I ever released it and called it functional.
     * 
     * TODO:
     *	Implement ID3v2 reader and maybe writer if enought people want it.
     * 
     * The most recent version is available at:
     *	http://Leknor.com/code/
     *
     */

    var $_version = 1.24; // Version of the id3 class


    var $file = false;		// mp3/mpeg file name

    var $id3v1 = false;		// ID3 v1 tag found? (also true if v1.1 found)
    var $id3v11 = false;	// ID3 v1.1 tag found?
    var $id3v2 = false;		// ID3 v2 tag found? (not used yet)

    // ID3v1.1 Fields:
    var $name = '';		// track name
    var $artists = '';		// artists
    var $album = '';		// album
    var $year = '';		// year
    var $comment = '';		// comment
    var $track = 0;		// track number
    var $genre = '';		// genre name
    var $genreno = 255;		// genre number

    // MP3 Frame Stuff
    var $studied = false;	// Was the file studied to learn more info?
    var $mpeg_ver = false;	// version of mpeg
    var $layer = false;		// version of layer
    var $bitrate = false;	// bitrate
    var $crc = false;		// Frames are crc protected?
    var $frequency = 0;		// Frequency
    var $padding = false;	// Frames padded
    var $private = false;	// Private bit set?
    var $mode = '';		// Mode (Stereo etc)
    var $copyright = false;	// Copyrighted?
    var $original = false;	// On Original Media? (never used)
    var $emphasis = '';		// Emphasis (also never used)
    var $filesize = -1;		// Bytes in file
    var $frameoffset = -1;	// Byte at which the first mpeg header was found.

    var $length = false;	// length of mp3 format hh:ss
    var $lengths = false;	// length of mp3 in seconds

    var $error = false;		// if any errors they will be here

    var $debug = false;		// print debugging info?
    var $debugbeg = '<DIV STYLE="margin: 0.5 em; padding: 0.5 em; border-width: thin; border-color: black; border-style: solid">';
    var $debugend = '</DIV>';

    /*
     * id3 constructor - creates a new id3 object and maybe loads a tag
     * from a file.
     *
     * $file - the path to the mp3/mpeg file. When in doubt use a full path.
     * $study - (Optional) - study the mpeg frame to get extra info like bitrate and frequency
     *		You should advoid studing alot of files as it will siginficantly slow this down.
     */
    function id3($file, $study = false) {
	if (defined('ID3_SHOW_DEBUG')) $this->debug = true;
	if ($this->debug) print($this->debugbeg . "id3('$file')<HR>\n");

	$this->file = $file;
	$this->_read_v1();

	if ($study or defined('ID3_AUTO_STUDY'))
	    $this->study();

	if ($this->debug) print($this->debugend);
    } // id3($file)

    /*
     * write - update the id3v1 tags on the file.
     *
     * $v1 - if true update/create an id3v1 tag on the file. (defaults to true)
     *
     * Note: If/when ID3v2 is implemented this method will probably get another
     *       parameters.
     */
    function write($v1 = true) {
	if ($this->debug) print($this->debugbeg . "write()<HR>\n");
	if ($v1) {
	    $this->_write_v1();
	}
	if ($this->debug) print($this->debugend);
    } // write()

    /*
     * study() - does extra work to get the MPEG frame info.
     */
    function study() {
	$this->studied = true;
	$this->_readframe();
    } // study()

    /*
     * copy($from) - set's the ID3 fields to the same as the fields in $from
     */
    function copy($from) {
	if ($this->debug) print($this->debugbeg . "copy(\$from)<HR>\n");
	$this->name	= $from->name;
	$this->artists	= $from->artists;
	$this->album	= $from->album;
	$this->year	= $from->year;
	$this->comment	= $from->comment;
	$this->track	= $from->track;
	$this->genre	= $from->genre;
	$this->genreno	= $from->genreno;
	if ($this->debug) print($this->debugend);
    } // copy($from)

    /*
     * remove - removes the id3 tag(s) from a file.
     *
     * $id3v1 - true to remove the tag
     * $id3v2 - true to remove the tag (Not yet implemented)
     */
    function remove($id3v1 = true, $id3v2 = true) {
	if ($this->debug) print($this->debugbeg . "remove()<HR>\n");

	if ($id3v1) {
	    $this->_remove_v1();
	}

	if ($id3v2) {
	    // TODO: write ID3v2 code
	}

	if ($this->debug) print($this->debugend);
    } // remove


    /*
     * _read_v1 - read a ID3 v1 or v1.1 tag from a file
     *
     * $file should be the path to the mp3 to look for a tag.
     * When in doubt use the full path.
     *
     * if there is an error it will return false and a message will be
     * put in $this->error
     */
    function _read_v1() {
	if ($this->debug) print($this->debugbeg . "_read_v1()<HR>\n");

	if (! ($f = fopen($this->file, 'rb')) ) {
	    $this->error = 'Unable to open ' . $file;
	    return false;
	}

	if (fseek($f, -128, SEEK_END) == -1) {
	    $this->error = 'Unable to see to end - 128 of ' . $file;
	    return false;
	}

	$r = fread($f, 128);
	fclose($f);

	if ($this->debug) {
	    $unp = unpack('H*raw', $r);
	    print_r($unp);
	}

	$id3tag = $this->_decode_v1($r);

	if($id3tag) {
	    $this->id3v1 = true;

	    $tmp = explode(Chr(0), $id3tag['NAME']);
	    $this->name = $tmp[0];

	    $tmp = explode(Chr(0), $id3tag['ARTISTS']);
	    $this->artists = $tmp[0];

	    $tmp = explode(Chr(0), $id3tag['ALBUM']);
	    $this->album = $tmp[0];

	    $tmp = explode(Chr(0), $id3tag['YEAR']);
	    $this->year = $tmp[0];

	    $tmp = explode(Chr(0), $id3tag['COMMENT']);
	    $this->comment = $tmp[0];

	    if (isset($id3tag['TRACK'])) {
		$this->id3v11 = true;
		$this->track = $id3tag['TRACK'];
	    }

	    $this->genreno = $id3tag['GENRENO'];
	    $this->genre = $id3tag['GENRE'];
	}

	if ($this->debug) print($this->debugend);
    } // _read_v1()

    /*
     * _decode_v1 - decodes that ID3v1 or ID3v1.1 tag
     *
     * false will be returned if there was an error decoding the tag
     * else an array will be returned
     */
    function _decode_v1($rawtag) {
	if ($this->debug) print($this->debugbeg . "_decode_v1(\$rawtag)<HR>\n");

	if ($rawtag[125] == Chr(0) and $rawtag[126] != Chr(0)) {
	    // ID3 v1.1
	    $format = 'a3TAG/a30NAME/a30ARTISTS/a30ALBUM/a4YEAR/a28COMMENT/x1/C1TRACK/C1GENRENO';
	} else {
	    // ID3 v1
	    $format = 'a3TAG/a30NAME/a30ARTISTS/a30ALBUM/a4YEAR/a30COMMENT/C1GENRENO';
	}

	$id3tag = unpack($format, $rawtag);
	if ($this->debug) print_r($id3tag);

	if ($id3tag['TAG'] == 'TAG') {
	    $id3tag['GENRE'] = $this->getgenre($id3tag['GENRENO']);
	} else {
	    $this->error = 'TAG not found';
	    $id3tag = false;
	}
	if ($this->debug) print($this->debugend);
	return $id3tag;
    } // _decode_v1()


    /*
     * _write_v1 - writes a ID3 v1 or v1.1 tag to a file
     *
     * if there is an error it will return false and a message will be
     * put in $this->error
     */
    function _write_v1() {
	if ($this->debug) print($this->debugbeg . "_write_v1()<HR>\n");

	$file = $this->file;

	if (! ($f = fopen($file, 'r+b')) ) {
	    $this->error = 'Unable to open ' . $file;
	    return false;
	}

	if (fseek($f, -128, SEEK_END) == -1) {
	    $this->error = 'Unable to see to end - 128 of ' . $file;
	    return false;
	}

	$this->genreno = $this->getgenreno($this->genre, $this->genreno);

	$newtag = $this->_encode_v1();

	$r = fread($f, 128);

	if ($this->_decode_v1($r)) {
	    if (fseek($f, -128, SEEK_END) == -1) {
		$this->error = 'Unable to see to end - 128 of ' . $file;
		return false;
	    }
	    fwrite($f, $newtag);
	} else {
	    if (fseek($f, 0, SEEK_END) == -1) {
		$this->error = 'Unable to see to end of ' . $file;
		return false;
	    }
	    fwrite($f, $newtag);
	}
	fclose($f);


	if ($this->debug) print($this->debugend);
    } // _write_v1()

    /*
     * _encode_v1 - encode the ID3 tag
     *
     * the newly built tag will be returned
     */
    function _encode_v1() {
	if ($this->debug) print($this->debugbeg . "_encode_v1()<HR>\n");

	if ($this->track) {
	    // ID3 v1.1
	    $id3pack = 'a3a30a30a30a4a28x1C1C1';
	    $newtag = pack($id3pack,
		    'TAG',
		    $this->name,
		    $this->artists,
		    $this->album,
		    $this->year,
		    $this->comment,
		    $this->track,
		    $this->genreno
			  );
	} else {
	    // ID3 v1
	    $id3pack = 'a3a30a30a30a4a30C1';
	    $newtag = pack($id3pack,
		    'TAG',
		    $this->name,
		    $this->artists,
		    $this->album,
		    $this->year,
		    $this->comment,
		    $this->genreno
			  );
	}

	if ($this->debug) {
	    print('id3pack: ' . $id3pack . "\n");
	    $unp = unpack('H*new', $newtag);
	    print_r($unp);
	}

	if ($this->debug) print($this->debugend);
	return $newtag;
    } // _encode_v1()

    /*
     * _remove_v1 - if exists it removes an ID3v1 or v1.1 tag
     *
     * returns true if the tag was removed or none was found
     * else false if there was an error
     */
    function _remove_v1() {
	if ($this->debug) print($this->debugbeg . "_remove_v1()<HR>\n");

	$file = $this->file;

	if (! ($f = fopen($file, 'r+b')) ) {
	    $this->error = 'Unable to open ' . $file;
	    return false;
	}

	if (fseek($f, -128, SEEK_END) == -1) {
	    $this->error = 'Unable to see to end - 128 of ' . $file;
	    return false;
	}

	$r = fread($f, 128);

	$success = false;
	if ($this->_decode_v1($r)) {
	    $size = filesize($this->file) - 128;
	    if ($this->debug) print('size: old: ' . filesize($this->file));
	    $success = ftruncate($f, $size);	
	    clearstatcache();
	    if ($this->debug) print(' new: ' . filesize($this->file));
	}
	fclose($f);
	if ($this->debug) print($this->debugend);
	return $success;
    } // _remove_v1()

    function _readframe() {
	if ($this->debug) print($this->debugbeg . "_readframe()<HR>\n");

	$file = $this->file;

	if (! ($f = fopen($file, 'rb')) ) {
	    $this->error = 'Unable to open ' . $file;
	    if ($this->debug) print($this->debugend);
	    return false;
	}

	$this->filesize = filesize($file);

	do {
	    while (fread($f,1) != Chr(255)) { // Find the first frame
		//if ($this->debug) echo "Find...\n";
		if (feof($f)) {
		    $this->error = 'No mpeg frame found';
		    if ($this->debug) print($this->debugend);
		    return false;
		}
	    }
	    fseek($f, ftell($f) - 1); // back up one byte

	    $frameoffset = ftell($f);

	    $r = fread($f, 4);
	    // Binary to Hex to a binary sting. ugly but best I can think of.
	    $bits = unpack('H*bits', $r);
	    $bits =  base_convert($bits['bits'],16,2);
	} while (!$bits[8] and !$bits[9] and !$bits[10]); // 1st 8 bits true from the while
	if ($this->debug) print('Bits: ' . $bits . "\n");

	$this->frameoffset = $frameoffset;

	fclose($f);

	if ($bits[11] == 0) {
	    $this->mpeg_ver = "2.5";
	    $bitrates = array(
		    '1' => array(0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0),
		    '2' => array(0,  8, 16, 24, 32, 40, 48,  56,  64,  80,  96, 112, 128, 144, 160, 0),
		    '3' => array(0,  8, 16, 24, 32, 40, 48,  56,  64,  80,  96, 112, 128, 144, 160, 0),
			     );
	} else if ($bits[12] == 0) {
	    $this->mpeg_ver = "2";
	    $bitrates = array(
		    '1' => array(0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0),
		    '2' => array(0,  8, 16, 24, 32, 40, 48,  56,  64,  80,  96, 112, 128, 144, 160, 0),
		    '3' => array(0,  8, 16, 24, 32, 40, 48,  56,  64,  80,  96, 112, 128, 144, 160, 0),
			     );
	} else {
	    $this->mpeg_ver = "1";
	    $bitrates = array(
		    '1' => array(0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0),
		    '2' => array(0, 32, 48, 56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 384, 0),
		    '3' => array(0, 32, 40, 48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 0),
			     );
	}
	if ($this->debug) print('MPEG' . $this->mpeg_ver . "\n");

	$layer = array(
		array(0,3),
		array(2,1),
		      );
	$this->layer = $layer[$bits[13]][$bits[14]];
	if ($this->debug) print('layer: ' . $this->layer . "\n");

	if ($bits[15] == 0) {
	    // It's backwards, if the bit is not set then it is protected.
	    if ($this->debug) print("protected (crc)\n");
	    $this->crc = true;
	}

	$bitrate = 0;
	if ($bits[16] == 1) $bitrate += 8;
	if ($bits[17] == 1) $bitrate += 4;
	if ($bits[18] == 1) $bitrate += 2;
	if ($bits[19] == 1) $bitrate += 1;
	$this->bitrate = $bitrates[$this->layer][$bitrate];

	$frequency = array(
		'1' => array(
		    '0' => array(44100, 48000),
		    '1' => array(32000, 0),
			    ),
		'2' => array(
		    '0' => array(22050, 24000),
		    '1' => array(16000, 0),
			    ),
		'2.5' => array(
		    '0' => array(11025, 12000),
		    '1' => array(8000, 0),
			      ),
		  );
	$this->frequency = $frequency[$this->mpeg_ver][$bits[20]][$bits[21]];

	$this->padding = $bits[22];
	$this->private = $bits[23];

	$mode = array(
		array('Stereo', 'Joint Stereo'),
		array('Dual Channel', 'Mono'),
		     );
	$this->mode = $mode[$bits[24]][$bits[25]];

	// XXX: I dunno what the mode extension is for bits 26,27

	$this->copyright = $bits[28];
	$this->original = $bits[29];

	$emphasis = array(
		array('none', '50/15ms'),
		array('', 'CCITT j.17'),
			 );
	$this->emphasis = $emphasis[$bits[30]][$bits[31]];

	if ($this->bitrate == 0) {
	    $s = -1;
	} else {
	    $s = ((8*filesize($this->file))/1000) / $this->bitrate;        
	}
	$this->length = sprintf('%02d:%02d',floor($s/60),floor($s-(floor($s/60)*60)));
	$this->lengths = (int)$s;

	if ($this->debug) print($this->debugend);
    } // _readframe()

    /*
     * getgenre - return the name of a genre number
     *
     * if no genre number is specified the genre number from
     * $this->genreno will be used.
     *
     * the genre is returned or false if an error or not found
     * no error message is ever returned
     */
    function getgenre($genreno) {
	if ($this->debug) print($this->debugbeg . "getgenre($genreno)<HR>\n");

	$genres = $this->genres();
	if (isset($genres[$genreno])) {
	    $genre = $genres[$genreno];
	    if ($this->debug) print($genre . "\n");
	} else {
	    $genre = '';
	}

	if ($this->debug) print($this->debugend);
	return $genre;
    } // getgenre($genreno)

    /*
     * getgenreno - return the number of the genre name
     *
     * the genre number is returned or 0xff (255) if a match is not found
     * you can specify the default genreno to use if one is not found
     * no error message is ever returned
     */
    function getgenreno($genre, $default = 0xff) {
	if ($this->debug) print($this->debugbeg . "getgenreno('$genre',$default)<HR>\n");

	$genres = $this->genres();
	$genreno = false;
	if ($genre) {
	    foreach ($genres as $no => $name) {
		if (strtolower($genre) == strtolower($name)) {
		    if ($this->debug) print("$no:'$name' == '$genre'");
		    $genreno = $no;
		}
	    }
	}
	if ($genreno === false) $genreno = $default;
	if ($this->debug) print($this->debugend);
	return $genreno;
    } // getgenreno($genre, $default = 0xff)

    /*
     * genres - reuturns an array of the ID3v1 genres
     */
    function genres() {
	return array(
		0   => 'Blues',
		1   => 'Classic Rock',
		2   => 'Country',
		3   => 'Dance',
		4   => 'Disco',
		5   => 'Funk',
		6   => 'Grunge',
		7   => 'Hip-Hop',
		8   => 'Jazz',
		9   => 'Metal',
		10  => 'New Age',
		11  => 'Oldies',
		12  => 'Other',
		13  => 'Pop',
		14  => 'R&B',
		15  => 'Rap',
		16  => 'Reggae',
		17  => 'Rock',
		18  => 'Techno',
		19  => 'Industrial',
		20  => 'Alternative',
		21  => 'Ska',
		22  => 'Death Metal',
		23  => 'Pranks',
		24  => 'Soundtrack',
		25  => 'Euro-Techno',
		26  => 'Ambient',
		27  => 'Trip-Hop',
		28  => 'Vocal',
		29  => 'Jazz+Funk',
		30  => 'Fusion',
		31  => 'Trance',
		32  => 'Classical',
		33  => 'Instrumental',
		34  => 'Acid',
		35  => 'House',
		36  => 'Game',
		37  => 'Sound Clip',
		38  => 'Gospel',
		39  => 'Noise',
		40  => 'Alternative Rock',
		41  => 'Bass',
		42  => 'Soul',
		43  => 'Punk',
		44  => 'Space',
		45  => 'Meditative',
		46  => 'Instrumental Pop',
		47  => 'Instrumental Rock',
		48  => 'Ethnic',
		49  => 'Gothic',
		50  => 'Darkwave',
		51  => 'Techno-Industrial',
		52  => 'Electronic',
		53  => 'Pop-Folk',
		54  => 'Eurodance',
		55  => 'Dream',
		56  => 'Southern Rock',
		57  => 'Comedy',
		58  => 'Cult',
		59  => 'Gangsta',
		60  => 'Top 40',
		61  => 'Christian Rap',
		62  => 'Pop/Funk',
		63  => 'Jungle',
		64  => 'Native US',
		65  => 'Cabaret',
		66  => 'New Wave',
		67  => 'Psychadelic',
		68  => 'Rave',
		69  => 'Showtunes',
		70  => 'Trailer',
		71  => 'Lo-Fi',
		72  => 'Tribal',
		73  => 'Acid Punk',
		74  => 'Acid Jazz',
		75  => 'Polka',
		76  => 'Retro',
		77  => 'Musical',
		78  => 'Rock & Roll',
		79  => 'Hard Rock',
		80  => 'Folk',
		81  => 'Folk-Rock',
		82  => 'National Folk',
		83  => 'Swing',
		84  => 'Fast Fusion',
		85  => 'Bebob',
		86  => 'Latin',
		87  => 'Revival',
		88  => 'Celtic',
		89  => 'Bluegrass',
		90  => 'Avantgarde',
		91  => 'Gothic Rock',
		92  => 'Progressive Rock',
		93  => 'Psychedelic Rock',
		94  => 'Symphonic Rock',
		95  => 'Slow Rock',
		96  => 'Big Band',
		97  => 'Chorus',
		98  => 'Easy Listening',
		99  => 'Acoustic',
		100 => 'Humour',
		101 => 'Speech',
		102 => 'Chanson',
		103 => 'Opera',
		104 => 'Chamber Music',
		105 => 'Sonata',
		106 => 'Symphony',
		107 => 'Booty Bass',
		108 => 'Primus',
		109 => 'Porn Groove',
		110 => 'Satire',
		111 => 'Slow Jam',
		112 => 'Club',
		113 => 'Tango',
		114 => 'Samba',
		115 => 'Folklore',
		116 => 'Ballad',
		117 => 'Power Ballad',
		118 => 'Rhytmic Soul',
		119 => 'Freestyle',
		120 => 'Duet',
		121 => 'Punk Rock',
		122 => 'Drum Solo',
		123 => 'Acapella',
		124 => 'Euro-House',
		125 => 'Dance Hall',
		126 => 'Goa',
		127 => 'Drum & Bass',
		128 => 'Club-House',
		129 => 'Hardcore',
		130 => 'Terror',
		131 => 'Indie',
		132 => 'BritPop',
		133 => 'Negerpunk',
		134 => 'Polsk Punk',
		135 => 'Beat',
		136 => 'Christian Gangsta Rap',
		137 => 'Heavy Metal',
		138 => 'Black Metal',
		139 => 'Crossover',
		140 => 'Contemporary Christian',
		141 => 'Christian Rock',
		142 => 'Merengue',
		143 => 'Salsa',
		144 => 'Trash Metal',
		145 => 'Anime',
		146 => 'Jpop',
		147 => 'Synthpop'
		    );
    } // genres
} // end of id3

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