<?php

// THIS IS BETA. DO NOT USE UNLESS YOU ENJOY THE RISK OF VERY BAD THINGS
// HAPPENING TO YOUR DATA. That said, it doesn't write anything so it
// should be harmless. This has been tested on a few ogg files I've
// created for testing but that is it.

// 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('OGG_SHOW_DEBUG', true);

class ogg {
    /*
     * ogg - A Class for reading Ogg comment 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 Ogg files but you
     * are on your own if bad things happen.
     *
     * To use this code first create a new instance on a file. Then loop
     * though the $ogg->fields array. Inside that loop, loop again. The
     * ogg comment format allows mome then one field with the same name
     * so it is possible for the ARTIST fields to appear twice if a work
     * has two performers.
     *
     * eg:
     *	require_once('class.ogg.php');
     *	$ogg = new ogg('/path/to/filename.ogg');
     *	echo '<UL>';
     *	foreach ($ogg->fields AS $name => $val) {
     *	    echo "<LI>$name:<OL>";
     *	    foreach ($val AS $contents) {
     *		echo '<LI>', $contents;
     *	    }
     *	    echo '</OL>';
     *	}
     *	echo '</UL>';
     *
     * This site was useful to me:
     *	http://www.xiph.org/ogg/vorbis/docs.html
     *
     * Change Log:
     *	0.10:	Clean up for release.
     *	0.01:	Got off my ass and wrote something until it works enough.
     * 
     * Thanks To:
     *
     * TODO:
     *	Collect nifty info like bitrate, etc...
     *	Maybe implement ogg comment writer. We'll see I don't like using php
     *	    to manipulate large amounts of data.
     * 
     * The most recent version is available at:
     *	http://Leknor.com/code/
     *
     */

    var $_version = 0.10;	// Version of the ogg class (float, not major/minor)

    var $file = false;		// ogg file name (you should never modify this)

    var $fields = array();	// comments fields, this is a two dimentional array.
    var $_rawfields = array();	// The comments fields read and split but not
orgainzed.

    var $error = false;		// Check here for an error message
    var $debug = false;		// print debugging info?
    var $debugbeg = '';
    var $debugend = '';

    /*
     * ogg constructor - creates a new ogg object
     *
     * $file - the path to the ogg file. When in doubt use a full path.
     */
    function ogg($file) {
	if (defined('OGG_SHOW_DEBUG')) $this->debug = true;
	if ($this->debug) print($this->debugbeg . "ogg('$file')<HR>\n");

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

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

    /*
     * _read() - finds the comment in a ogg stream. You should not call this.
     */
    function _read() {
	if ($this->debug) print($this->debugbeg . "_read()<HR>\n");

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

	$this->_find_page($f);
	$this->_find_page($f);

	fseek($f, 26 - 4, SEEK_CUR);
	$segs = fread($f, 1);
	$segs = unpack('C1size', $segs);
	$segs = $segs['size'];
	if ($this->debug) print("segs: $segs<BR>");
	fseek($f, $segs, SEEK_CUR);

	// Skip preable
	//$r = fread($f, 1);
	//print_r(unpack('H*raw', $r));
	fseek($f, 7, SEEK_CUR);

	// Skip Vendor
	$size = fread($f, 4);
	$size = unpack('V1size', $size);
	$size = $size['size'];
	if ($this->debug) print("vendor size: $size<BR>");
	fseek($f, $size, SEEK_CUR);

	// Comments
	$comments = fread($f, 4);
	$comments = unpack('V1comments', $comments);
	$comments = $comments['comments'];
	if ($this->debug) print("Comments: $comments<BR>");
	for ($i=0; $i < $comments; $i++) {
	    $size = fread($f, 4);
	    $size = unpack('V1size', $size);
	    $size = $size['size'];
	    if ($this->debug) print("comment size: $size<BR>");

	    $comment = fread($f, $size);
	    if ($this->debug) print("comment: $comment<BR>");
	    $comment = explode('=', $comment, 2);
	    $this->fields[strtoupper($comment[0])][] = $comment[1];
	    $this->_rawfields[] = $comment;
	}

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

    /*
     * _find_page - seeks to the next ogg page start.
     */
    function _find_page(&$f) {
	if ($this->debug) print($this->debugbeg . "_find_page($f)<HR>\n");

	$header = 'OggS'; // 0xf4 . 0x67 . 0x 67 . 0x53
	$bytes = fread($f, 4);

	while ($header != $bytes) {
	    //if ($this->debug) print('.');
	    $bytes = substr($bytes, 1);
	    $bytes .= fread($f, 1);
	}

	if ($this->debug) {
	    echo 'Page found at byte: ', ftell($f) - 4, '<BR>';
	    print($this->debugend);
	}
    } // _find_page(&$file)

} // end of class ogg

?>