path: root/modules/mpd/mpd.class.php

<?php
/*
 *  mpd.class.php - PHP Object Interface to the MPD Music Player Daemon
 *  Version 1.2, Released 05/05/2004
 *  Copyright (C) 2003-2004  Benjamin Carlisle (bcarlisle@24oz.com)
 *  http://mpd.24oz.com/ | http://www.musicpd.org/
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */ 

// Create common command definitions for MPD to use
define("MPD_CMD_STATUS",      "status");
define("MPD_CMD_STATISTICS",  "stats");
define("MPD_CMD_VOLUME",      "volume");
define("MPD_CMD_SETVOL",      "setvol");
define("MPD_CMD_PLAY",        "play");
define("MPD_CMD_STOP",        "stop");
define("MPD_CMD_PAUSE",       "pause");
define("MPD_CMD_NEXT",        "next");
define("MPD_CMD_PREV",        "previous");
define("MPD_CMD_PLLIST",      "playlistinfo");
define("MPD_CMD_PLADD",       "add");
define("MPD_CMD_PLREMOVE",    "delete");
define("MPD_CMD_PLCLEAR",     "clear");
define("MPD_CMD_PLSHUFFLE",   "shuffle");
define("MPD_CMD_PLLOAD",      "load");
define("MPD_CMD_PLSAVE",      "save");
define("MPD_CMD_KILL",        "kill");
define("MPD_CMD_REFRESH",     "update");
define("MPD_CMD_REPEAT",      "repeat");
define("MPD_CMD_LSDIR",       "lsinfo");
define("MPD_CMD_SEARCH",      "search");
define("MPD_CMD_START_BULK",  "command_list_begin");
define("MPD_CMD_END_BULK",    "command_list_end");
define("MPD_CMD_FIND",        "find");
define("MPD_CMD_RANDOM",      "random");
define("MPD_CMD_SEEK",        "seek");
define("MPD_CMD_PLSWAPTRACK", "swap");
define("MPD_CMD_PLMOVETRACK", "move");
define("MPD_CMD_PASSWORD",    "password");
define("MPD_CMD_TABLE",       "list");

// Predefined MPD Response messages
define("MPD_RESPONSE_ERR", "ACK");
define("MPD_RESPONSE_OK",  "OK");

// MPD State Constants
define("MPD_STATE_PLAYING", "play");
define("MPD_STATE_STOPPED", "stop");
define("MPD_STATE_PAUSED",  "pause");

// MPD Searching Constants
define("MPD_SEARCH_ARTIST", "artist");
define("MPD_SEARCH_TITLE",  "title");
define("MPD_SEARCH_ALBUM",  "album");

// MPD Cache Tables
define("MPD_TBL_ARTIST","artist");
define("MPD_TBL_ALBUM","album");

class mpd {
	// TCP/Connection variables
	var $host;
	var $port;
        var $password;

	var $mpd_sock   = NULL;
	var $connected  = FALSE;

	// MPD Status variables
	var $mpd_version    = "(unknown)";

	var $state;
	var $current_track_position;
	var $current_track_length;
	var $current_track_id;
	var $volume;
	var $repeat;
	var $random;

	var $uptime;
	var $playtime;
	var $db_last_refreshed;
	var $num_songs_played;
	var $playlist_count;
	
	var $num_artists;
	var $num_albums;
	var $num_songs;
	
	var $playlist		= array();

	// Misc Other Vars	
	var $mpd_class_version = "1.2";

	var $debugging   = FALSE;    // Set to TRUE to turn extended debugging on.
	var $errStr      = "";       // Used for maintaining information about the last error message

	var $command_queue;          // The list of commands for bulk command sending

    // =================== BEGIN OBJECT METHODS ================

	/* mpd() : Constructor
	 * 
	 * Builds the MPD object, connects to the server, and refreshes all local object properties.
	 */
	function mpd($srv,$port,$pwd = NULL) {
		$this->host = $srv;
		$this->port = $port;
        	$this->password = $pwd;
		
		$resp = $this->Connect();
		if ( is_null($resp) ) {
       			$this->errStr = "Could not connect";
			return;
		} 
		else {	list ( $this->mpd_version ) = sscanf($resp, MPD_RESPONSE_OK . " MPD %s\n");
                
		if ( ! is_null($pwd) ) {
                if ( is_null($this->SendCommand(MPD_CMD_PASSWORD,$pwd)) ) {
                    $this->connected = FALSE;
		    $this->errStr = "Password supplied is incorrect or Invalid Command";
                    return;  // bad password or command
                }
    			
		if ( is_null($this->RefreshInfo()) ) { // no read access -- might as well be disconnected!
                    $this->connected = FALSE;
                    $this->errStr = "Password supplied does not have read access";
                    return;
                }
            } else {
    			if ( is_null($this->RefreshInfo()) ) { // no read access -- might as well be disconnected!
                    $this->connected = FALSE;
                    $this->errStr = "Password required to access server";
                    return; 
                }
            }
		}
	}

	/* Connect()
	 * 
	 * Connects to the MPD server. 
	 * 
	 * NOTE: This is called automatically upon object instantiation; you should not need to call this directly.
	 */
	function Connect() {
		if ( $this->debugging ) echo "mpd->Connect() / host: ".$this->host.", port: ".$this->port."\n";
		$this->mpd_sock = fsockopen($this->host,$this->port,$errNo,$errStr,3);
		
		/* Vollmerize this bizatch, if we've got php4.3+ we should 
		 * have these functions and we need them
		 */
		if (function_exists('stream_set_timeout')) { 
		
			/* Set the timeout on the connection */
			stream_set_timeout($this->mpd_sock,2);
			
			/* We want blocking, cause otherwise it doesn't
			 * timeout, and feof just keeps on spinning 
			 */
			stream_set_blocking($this->mpd_sock,TRUE);
			$status = socket_get_status($this->mpd_sock);
		}
		if (!$this->mpd_sock) {
			$this->errStr = "Socket Error: $errStr ($errNo)";
			return NULL;
		} else {
			while(!feof($this->mpd_sock) && !$status['timed_out']) {
				$response =  fgets($this->mpd_sock,1024);
				if (function_exists('socket_get_status')) { 
					$status = socket_get_status($this->mpd_sock);
				}
				if (strncmp(MPD_RESPONSE_OK,$response,strlen(MPD_RESPONSE_OK)) == 0) {
					$this->connected = TRUE;
					return $response;
					break;
				}
				if (strncmp(MPD_RESPONSE_ERR,$response,strlen(MPD_RESPONSE_ERR)) == 0) {
					$this->errStr = "Server responded with: $response";
					return NULL;
				}

				
			} // end while
			// Generic response
			$this->errStr = "Connection not available";
			return NULL;
		}
	}

	/* SendCommand()
	 * 
	 * Sends a generic command to the MPD server. Several command constants are pre-defined for 
	 * use (see MPD_CMD_* constant definitions above). 
	 */
	function SendCommand($cmdStr,$arg1 = "",$arg2 = "") {
		if ( $this->debugging ) echo "mpd->SendCommand() / cmd: ".$cmdStr.", args: ".$arg1." ".$arg2."\n";
		if ( ! $this->connected ) {
			echo "mpd->SendCommand() / Error: Not connected\n";
		} else {
			// Clear out the error String
			$this->errStr = "";
			$respStr = "";

			// Check the command compatibility:
			if ( ! $this->_checkCompatibility($cmdStr) ) {
				return NULL;
			}

			if (strlen($arg1) > 0) $cmdStr .= " \"$arg1\"";
			if (strlen($arg2) > 0) $cmdStr .= " \"$arg2\"";
			fputs($this->mpd_sock,"$cmdStr\n");
			while(!feof($this->mpd_sock)) {
				$response = fgets($this->mpd_sock,1024);

				// An OK signals the end of transmission -- we'll ignore it
				if (strncmp(MPD_RESPONSE_OK,$response,strlen(MPD_RESPONSE_OK)) == 0) {
					break;
				}

				// An ERR signals the end of transmission with an error! Let's grab the single-line message.
				if (strncmp(MPD_RESPONSE_ERR,$response,strlen(MPD_RESPONSE_ERR)) == 0) {
					list ( $junk, $errTmp ) = split(MPD_RESPONSE_ERR . " ",$response );
					$this->errStr = strtok($errTmp,"\n");
				}

				if ( strlen($this->errStr) > 0 ) {
					return NULL;
				}

				// Build the response string
				$respStr .= $response;
			}
			if ( $this->debugging ) echo "mpd->SendCommand() / response: '".$respStr."'\n";
		}
		return $respStr;
	}

	/* QueueCommand() 
	 *
	 * Queues a generic command for later sending to the MPD server. The CommandQueue can hold 
	 * as many commands as needed, and are sent all at once, in the order they are queued, using 
	 * the SendCommandQueue() method. The syntax for queueing commands is identical to SendCommand(). 
     */
	function QueueCommand($cmdStr,$arg1 = "",$arg2 = "") {
		if ( $this->debugging ) echo "mpd->QueueCommand() / cmd: ".$cmdStr.", args: ".$arg1." ".$arg2."\n";
		if ( ! $this->connected ) {
			echo "mpd->QueueCommand() / Error: Not connected\n";
			return NULL;
		} else {
			if ( strlen($this->command_queue) == 0 ) {
				$this->command_queue = MPD_CMD_START_BULK . "\n";
			}
			if (strlen($arg1) > 0) $cmdStr .= " \"$arg1\"";
			if (strlen($arg2) > 0) $cmdStr .= " \"$arg2\"";

			$this->command_queue .= $cmdStr ."\n";

			if ( $this->debugging ) echo "mpd->QueueCommand() / return\n";
		}
		return TRUE;
	}

	/* SendCommandQueue() 
	 *
	 * Sends all commands in the Command Queue to the MPD server. See also QueueCommand().
     */
	function SendCommandQueue() {
		if ( $this->debugging ) echo "mpd->SendCommandQueue()\n";
		if ( ! $this->connected ) {
			echo "mpd->SendCommandQueue() / Error: Not connected\n";
			return NULL;
		} else {
			$this->command_queue .= MPD_CMD_END_BULK . "\n";
			if ( is_null($respStr = $this->SendCommand($this->command_queue)) ) {
				return NULL;
			} else {
				$this->command_queue = NULL;
				if ( $this->debugging ) echo "mpd->SendCommandQueue() / response: '".$respStr."'\n";
			}
		}
		return $respStr;
	}

	/* AdjustVolume() 
	 *
	 * Adjusts the mixer volume on the MPD by <modifier>, which can be a positive (volume increase),
	 * or negative (volume decrease) value. 
     */
	function AdjustVolume($modifier) {
		if ( $this->debugging ) echo "mpd->AdjustVolume()\n";
		if ( ! is_numeric($modifier) ) {
			$this->errStr = "AdjustVolume() : argument 1 must be a numeric value";
			return NULL;
		}

        $this->RefreshInfo();
        $newVol = $this->volume + $modifier;
        $ret = $this->SetVolume($newVol);

		if ( $this->debugging ) echo "mpd->AdjustVolume() / return\n";
		return $ret;
	}

	/* SetVolume() 
	 *
	 * Sets the mixer volume to <newVol>, which should be between 1 - 100.
     */
	function SetVolume($newVol) {
		if ( $this->debugging ) echo "mpd->SetVolume()\n";
		if ( ! is_numeric($newVol) ) {
			$this->errStr = "SetVolume() : argument 1 must be a numeric value";
			return NULL;
		}

        // Forcibly prevent out of range errors
		if ( $newVol < 0 )   $newVol = 0;
		if ( $newVol > 100 ) $newVol = 100;

        // If we're not compatible with SETVOL, we'll try adjusting using VOLUME
        if ( $this->_checkCompatibility(MPD_CMD_SETVOL) ) {
            if ( ! is_null($ret = $this->SendCommand(MPD_CMD_SETVOL,$newVol))) $this->volume = $newVol;
        } else {
    		$this->RefreshInfo();     // Get the latest volume
    		if ( is_null($this->volume) ) {
    			return NULL;
    		} else {
    			$modifier = ( $newVol - $this->volume );
                if ( ! is_null($ret = $this->SendCommand(MPD_CMD_VOLUME,$modifier))) $this->volume = $newVol;
    		}
        }

		if ( $this->debugging ) echo "mpd->SetVolume() / return\n";
		return $ret;
	}

	/* GetDir() 
	 * 
     * Retrieves a database directory listing of the <dir> directory and places the results into
	 * a multidimensional array. If no directory is specified, the directory listing is at the 
	 * base of the MPD music path. 
	 */
	function GetDir($dir = "") {
		if ( $this->debugging ) echo "mpd->GetDir()\n";
		$resp = $this->SendCommand(MPD_CMD_LSDIR,$dir);
		$dirlist = $this->_parseFileListResponse($resp);
		if ( $this->debugging ) echo "mpd->GetDir() / return ".print_r($dirlist)."\n";
		return $dirlist;
	}

	/* PLAdd() 
	 * 
     * Adds each track listed in a single-dimensional <trackArray>, which contains filenames 
	 * of tracks to add, to the end of the playlist. This is used to add many, many tracks to 
	 * the playlist in one swoop.
	 */
	function PLAddBulk($trackArray) {
		if ( $this->debugging ) echo "mpd->PLAddBulk()\n";
		$num_files = count($trackArray);
		for ( $i = 0; $i < $num_files; $i++ ) {
			$this->QueueCommand(MPD_CMD_PLADD,$trackArray[$i]);
		}
		$resp = $this->SendCommandQueue();
		$this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLAddBulk() / return\n";
		return $resp;
	}

	/* PLAdd() 
	 * 
	 * Adds the file <file> to the end of the playlist. <file> must be a track in the MPD database. 
	 */
	function PLAdd($fileName) {
		if ( $this->debugging ) echo "mpd->PLAdd()\n";
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLADD,$fileName))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLAdd() / return\n";
		return $resp;
	}

	/* PLMoveTrack() 
	 * 
	 * Moves track number <origPos> to position <newPos> in the playlist. This is used to reorder 
	 * the songs in the playlist.
	 */
	function PLMoveTrack($origPos, $newPos) {
		if ( $this->debugging ) echo "mpd->PLMoveTrack()\n";
		if ( ! is_numeric($origPos) ) {
			$this->errStr = "PLMoveTrack(): argument 1 must be numeric";
			return NULL;
		} 
		if ( $origPos < 0 or $origPos > $this->playlist_count ) {
			$this->errStr = "PLMoveTrack(): argument 1 out of range";
			return NULL;
		}
		if ( $newPos < 0 ) $newPos = 0;
		if ( $newPos > $this->playlist_count ) $newPos = $this->playlist_count;
		
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLMOVETRACK,$origPos,$newPos))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLMoveTrack() / return\n";
		return $resp;
	}

	/* PLShuffle() 
	 * 
	 * Randomly reorders the songs in the playlist.
	 */
	function PLShuffle() {
		if ( $this->debugging ) echo "mpd->PLShuffle()\n";
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLSHUFFLE))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLShuffle() / return\n";
		return $resp;
	}

	/* PLLoad() 
	 * 
	 * Retrieves the playlist from <file>.m3u and loads it into the current playlist. 
	 */
	function PLLoad($file) {
		if ( $this->debugging ) echo "mpd->PLLoad()\n";
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLLOAD,$file))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLLoad() / return\n";
		return $resp;
	}

	/* PLSave() 
	 * 
	 * Saves the playlist to <file>.m3u for later retrieval. The file is saved in the MPD playlist
	 * directory.
	 */
	function PLSave($file) {
		if ( $this->debugging ) echo "mpd->PLSave()\n";
		$resp = $this->SendCommand(MPD_CMD_PLSAVE,$file);
		if ( $this->debugging ) echo "mpd->PLSave() / return\n";
		return $resp;
	}

	/* PLClear() 
	 * 
	 * Empties the playlist.
	 */
	function PLClear() {
		if ( $this->debugging ) echo "mpd->PLClear()\n";
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLCLEAR))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLClear() / return\n";
		return $resp;
	}

	/* PLRemove() 
	 * 
	 * Removes track <id> from the playlist.
	 */
	function PLRemove($id) {
		if ( $this->debugging ) echo "mpd->PLRemove()\n";
		if ( ! is_numeric($id) ) {
			$this->errStr = "PLRemove() : argument 1 must be a numeric value";
			return NULL;
		}
		if ( ! is_null($resp = $this->SendCommand(MPD_CMD_PLREMOVE,$id))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->PLRemove() / return\n";
		return $resp;
	}

	/* SetRepeat() 
	 * 
	 * Enables 'loop' mode -- tells MPD continually loop the playlist. The <repVal> parameter 
	 * is either 1 (on) or 0 (off).
	 */
	function SetRepeat($repVal) {
		if ( $this->debugging ) echo "mpd->SetRepeat()\n";
		$rpt = $this->SendCommand(MPD_CMD_REPEAT,$repVal);
		$this->repeat = $repVal;
		if ( $this->debugging ) echo "mpd->SetRepeat() / return\n";
		return $rpt;
	}

	/* SetRandom() 
	 * 
	 * Enables 'randomize' mode -- tells MPD to play songs in the playlist in random order. The
	 * <rndVal> parameter is either 1 (on) or 0 (off).
	 */
	function SetRandom($rndVal) {
		if ( $this->debugging ) echo "mpd->SetRandom()\n";
		$resp = $this->SendCommand(MPD_CMD_RANDOM,$rndVal);
		$this->random = $rndVal;
		if ( $this->debugging ) echo "mpd->SetRandom() / return\n";
		return $resp;
	}

	/* Shutdown() 
	 * 
	 * Shuts down the MPD server (aka sends the KILL command). This closes the current connection, 
	 * and prevents future communication with the server. 
	 */
	function Shutdown() {
		if ( $this->debugging ) echo "mpd->Shutdown()\n";
		$resp = $this->SendCommand(MPD_CMD_SHUTDOWN);

		$this->connected = FALSE;
		unset($this->mpd_version);
		unset($this->errStr);
		unset($this->mpd_sock);

		if ( $this->debugging ) echo "mpd->Shutdown() / return\n";
		return $resp;
	}

	/* DBRefresh() 
	 * 
	 * Tells MPD to rescan the music directory for new tracks, and to refresh the Database. Tracks 
	 * cannot be played unless they are in the MPD database.
	 */
	function DBRefresh() {
		if ( $this->debugging ) echo "mpd->DBRefresh()\n";
		$resp = $this->SendCommand(MPD_CMD_REFRESH);
		
		// Update local variables
		$this->RefreshInfo();

		if ( $this->debugging ) echo "mpd->DBRefresh() / return\n";
		return $resp;
	}

	/* Play() 
	 * 
	 * Begins playing the songs in the MPD playlist. 
	 */
	function Play() {
		if ( $this->debugging ) echo "mpd->Play()\n";
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_PLAY) )) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->Play() / return\n";
		return $rpt;
	}

	/* Stop() 
	 * 
	 * Stops playing the MPD. 
	 */
	function Stop() {
		if ( $this->debugging ) echo "mpd->Stop()\n";
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_STOP) )) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->Stop() / return\n";
		return $rpt;
	}

	/* Pause() 
	 * 
	 * Toggles pausing on the MPD. Calling it once will pause the player, calling it again
	 * will unpause. 
	 */
	function Pause() {
		if ( $this->debugging ) echo "mpd->Pause()\n";
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_PAUSE) )) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->Pause() / return\n";
		return $rpt;
	}
	
	/* SeekTo() 
	 * 
	 * Skips directly to the <idx> song in the MPD playlist. 
	 */
	function SkipTo($idx) { 
		if ( $this->debugging ) echo "mpd->SkipTo()\n";
		if ( ! is_numeric($idx) ) {
			$this->errStr = "SkipTo() : argument 1 must be a numeric value";
			return NULL;
		}
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_PLAY,$idx))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->SkipTo() / return\n";
		return $idx;
	}

	/* SeekTo() 
	 * 
	 * Skips directly to a given position within a track in the MPD playlist. The <pos> argument,
	 * given in seconds, is the track position to locate. The <track> argument, if supplied is
	 * the track number in the playlist. If <track> is not specified, the current track is assumed.
	 */
	function SeekTo($pos, $track = -1) { 
		if ( $this->debugging ) echo "mpd->SeekTo()\n";
		if ( ! is_numeric($pos) ) {
			$this->errStr = "SeekTo() : argument 1 must be a numeric value";
			return NULL;
		}
		if ( ! is_numeric($track) ) {
			$this->errStr = "SeekTo() : argument 2 must be a numeric value";
			return NULL;
		}
		if ( $track == -1 ) { 
			$track = $this->current_track_id;
		} 
		
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_SEEK,$track,$pos))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->SeekTo() / return\n";
		return $pos;
	}

	/* Next() 
	 * 
	 * Skips to the next song in the MPD playlist. If not playing, returns an error. 
	 */
	function Next() {
		if ( $this->debugging ) echo "mpd->Next()\n";
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_NEXT))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->Next() / return\n";
		return $rpt;
	}

	/* Previous() 
	 * 
	 * Skips to the previous song in the MPD playlist. If not playing, returns an error. 
	 */
	function Previous() {
		if ( $this->debugging ) echo "mpd->Previous()\n";
		if ( ! is_null($rpt = $this->SendCommand(MPD_CMD_PREV))) $this->RefreshInfo();
		if ( $this->debugging ) echo "mpd->Previous() / return\n";
		return $rpt;
	}
	
	/* Search() 
	 * 
     * Searches the MPD database. The search <type> should be one of the following: 
     *        MPD_SEARCH_ARTIST, MPD_SEARCH_TITLE, MPD_SEARCH_ALBUM
     * The search <string> is a case-insensitive locator string. Anything that contains 
	 * <string> will be returned in the results. 
	 */
	function Search($type,$string) {
		if ( $this->debugging ) echo "mpd->Search()\n";
		if ( $type != MPD_SEARCH_ARTIST and
	         $type != MPD_SEARCH_ALBUM and
			 $type != MPD_SEARCH_TITLE ) {
			$this->errStr = "mpd->Search(): invalid search type";
			return NULL;
		} else {
			if ( is_null($resp = $this->SendCommand(MPD_CMD_SEARCH,$type,$string)))	return NULL;
			$searchlist = $this->_parseFileListResponse($resp);
		}
		if ( $this->debugging ) echo "mpd->Search() / return ".print_r($searchlist)."\n";
		return $searchlist;
	}

	/* Find() 
	 * 
	 * Find() looks for exact matches in the MPD database. The find <type> should be one of 
	 * the following: 
     *         MPD_SEARCH_ARTIST, MPD_SEARCH_TITLE, MPD_SEARCH_ALBUM
     * The find <string> is a case-insensitive locator string. Anything that exactly matches 
	 * <string> will be returned in the results. 
	 */
	function Find($type,$string) {
		if ( $this->debugging ) echo "mpd->Find()\n";
		if ( $type != MPD_SEARCH_ARTIST and
	         $type != MPD_SEARCH_ALBUM and
			 $type != MPD_SEARCH_TITLE ) {
			$this->errStr = "mpd->Find(): invalid find type";
			return NULL;
		} else {
			if ( is_null($resp = $this->SendCommand(MPD_CMD_FIND,$type,$string)))	return NULL;
			$searchlist = $this->_parseFileListResponse($resp);
		}
		if ( $this->debugging ) echo "mpd->Find() / return ".print_r($searchlist)."\n";
		return $searchlist;
	}

	/* Disconnect() 
	 * 
	 * Closes the connection to the MPD server.
	 */
	function Disconnect() {
		if ( $this->debugging ) echo "mpd->Disconnect()\n";
		fclose($this->mpd_sock);

		$this->connected = FALSE;
		unset($this->mpd_version);
		unset($this->errStr);
		unset($this->mpd_sock);
	}

	/* GetArtists() 
	 * 
	 * Returns the list of artists in the database in an associative array.
	*/
	function GetArtists() {
		if ( $this->debugging ) echo "mpd->GetArtists()\n";
		if ( is_null($resp = $this->SendCommand(MPD_CMD_TABLE, MPD_TBL_ARTIST)))	return NULL;
        $arArray = array();
        
        $arLine = strtok($resp,"\n");
        $arName = "";
        $arCounter = -1;
        while ( $arLine ) {
            list ( $element, $value ) = split(": ",$arLine);
            if ( $element == "Artist" ) {
            	$arCounter++;
            	$arName = $value;
            	$arArray[$arCounter] = $arName;
            }

            $arLine = strtok("\n");
        }
		if ( $this->debugging ) echo "mpd->GetArtists()\n";
        return $arArray;
    }

    /* GetAlbums() 
	 * 
	 * Returns the list of albums in the database in an associative array. Optional parameter
     * is an artist Name which will list all albums by a particular artist.
	*/
	function GetAlbums( $ar = NULL) {
		if ( $this->debugging ) echo "mpd->GetAlbums()\n";
		if ( is_null($resp = $this->SendCommand(MPD_CMD_TABLE, MPD_TBL_ALBUM, $ar )))	return NULL;
        $alArray = array();

        $alLine = strtok($resp,"\n");
        $alName = "";
        $alCounter = -1;
        while ( $alLine ) {
            list ( $element, $value ) = split(": ",$alLine);
            if ( $element == "Album" ) {
            	$alCounter++;
            	$alName = $value;
            	$alArray[$alCounter] = $alName;
            }

            $alLine = strtok("\n");
        }
		if ( $this->debugging ) echo "mpd->GetAlbums()\n";
        return $alArray;
    }

	//*******************************************************************************//
	//***************************** INTERNAL FUNCTIONS ******************************//
	//*******************************************************************************//

    /* _computeVersionValue()
     *
     * Computes a compatibility value from a version string
     *
     */
    function _computeVersionValue($verStr) {
		list ($ver_maj, $ver_min, $ver_rel ) = split("\.",$verStr);
		return ( 100 * $ver_maj ) + ( 10 * $ver_min ) + ( $ver_rel );
    }

	/* _checkCompatibility() 
	 * 
	 * Check MPD command compatibility against our internal table. If there is no version 
	 * listed in the table, allow it by default.
	*/
	function _checkCompatibility($cmd) {
        // Check minimum compatibility
		$req_ver_low = $this->COMPATIBILITY_MIN_TBL[$cmd];
		$req_ver_hi = $this->COMPATIBILITY_MAX_TBL[$cmd];

		$mpd_ver = $this->_computeVersionValue($this->mpd_version);

		if ( $req_ver_low ) {
			$req_ver = $this->_computeVersionValue($req_ver_low);

			if ( $mpd_ver < $req_ver ) {
				$this->errStr = "Command '$cmd' is not compatible with this version of MPD, version ".$req_ver_low." required";
				return FALSE;
			}
		}

        // Check maxmum compatibility -- this will check for deprecations
		if ( $req_ver_hi ) {
            $req_ver = $this->_computeVersionValue($req_ver_hi);

			if ( $mpd_ver > $req_ver ) {
				$this->errStr = "Command '$cmd' has been deprecated in this version of MPD.";
				return FALSE;
			}
		}

		return TRUE;
	}

	/* _parseFileListResponse() 
	 * 
	 * Builds a multidimensional array with MPD response lists.
     *
	 * NOTE: This function is used internally within the class. It should not be used.
	 */
	function _parseFileListResponse($resp) {
		if ( is_null($resp) ) {
			return NULL;
		} else {
			$plistArray = array();
			$plistLine = strtok($resp,"\n");
			$plistFile = "";
			$plCounter = -1;
			while ( $plistLine ) {
				list ( $element, $value ) = split(": ",$plistLine);
				if ( $element == "file" ) {
					$plCounter++;
					$plistFile = $value;
					$plistArray[$plCounter]["file"] = $plistFile;
				} else {
					$plistArray[$plCounter][$element] = $value;
				}

				$plistLine = strtok("\n");
			} 
		}
		return $plistArray;
	}

	/* RefreshInfo() 
	 * 
	 * Updates all class properties with the values from the MPD server.
     *
	 * NOTE: This function is automatically called upon Connect() as of v1.1.
	 */
	function RefreshInfo() {
        // Get the Server Statistics
		$statStr = $this->SendCommand(MPD_CMD_STATISTICS);
		if ( !$statStr ) {
			return NULL;
		} else {
			$stats = array();
			$statLine = strtok($statStr,"\n");
			while ( $statLine ) {
				list ( $element, $value ) = split(": ",$statLine);
				$stats[$element] = $value;
				$statLine = strtok("\n");
			} 
		}

        // Get the Server Status
		$statusStr = $this->SendCommand(MPD_CMD_STATUS);
		if ( ! $statusStr ) {
			return NULL;
		} else {
			$status = array();
			$statusLine = strtok($statusStr,"\n");
			while ( $statusLine ) {
				list ( $element, $value ) = split(": ",$statusLine);
				$status[$element] = $value;
				$statusLine = strtok("\n");
			}
		}

        // Get the Playlist
		$plStr = $this->SendCommand(MPD_CMD_PLLIST);
   		$this->playlist = $this->_parseFileListResponse($plStr);
    	$this->playlist_count = count($this->playlist);

        // Set Misc Other Variables
		$this->state = $status['state'];
		if ($status['playlistlength']>0) {
			$this->current_track_id = $status['song'];
		} else {
			$this->current_track_id = -1;
		}
		if ( ($this->state == MPD_STATE_PLAYING) || ($this->state == MPD_STATE_PAUSED) ) {
			list ($this->current_track_position, $this->current_track_length ) = split(":",$status['time']);
		} else {
//			$this->current_track_id = -1;
			$this->current_track_position = -1;
			$this->current_track_length = -1;
		}

		$this->repeat = $status['repeat'];
		$this->random = $status['random'];

		$this->db_last_refreshed = $stats['db_update'];

		$this->volume = $status['volume'];
		$this->uptime = $stats['uptime'];
		$this->playtime = $stats['playtime'];
		$this->num_songs_played = $stats['songs_played'];
		$this->num_artists = $stats['num_artists'];
		$this->num_songs = $stats['num_songs'];
		$this->num_albums = $stats['num_albums'];
		return TRUE;
	}

    /* ------------------ DEPRECATED METHODS -------------------*/
	/* GetStatistics() 
	 * 
	 * Retrieves the 'statistics' variables from the server and tosses them into an array.
     *
	 * NOTE: This function really should not be used. Instead, use $this->[variable]. The function
	 *   will most likely be deprecated in future releases.
	 */
	function GetStatistics() {
		if ( $this->debugging ) echo "mpd->GetStatistics()\n";
		$stats = $this->SendCommand(MPD_CMD_STATISTICS);
		if ( !$stats ) {
			return NULL;
		} else {
			$statsArray = array();
			$statsLine = strtok($stats,"\n");
			while ( $statsLine ) {
				list ( $element, $value ) = split(": ",$statsLine);
				$statsArray[$element] = $value;
				$statsLine = strtok("\n");
			} 
		}
		if ( $this->debugging ) echo "mpd->GetStatistics() / return: " . print_r($statsArray) ."\n";
		return $statsArray;
	}

	/* GetStatus() 
	 * 
	 * Retrieves the 'status' variables from the server and tosses them into an array.
     *
	 * NOTE: This function really should not be used. Instead, use $this->[variable]. The function
	 *   will most likely be deprecated in future releases.
	 */
	function GetStatus() {
		if ( $this->debugging ) echo "mpd->GetStatus()\n";
		$status = $this->SendCommand(MPD_CMD_STATUS);
		if ( ! $status ) {
			return NULL;
		} else {
			$statusArray = array();
			$statusLine = strtok($status,"\n");
			while ( $statusLine ) {
				list ( $element, $value ) = split(": ",$statusLine);
				$statusArray[$element] = $value;
				$statusLine = strtok("\n");
			}
		}
		if ( $this->debugging ) echo "mpd->GetStatus() / return: " . print_r($statusArray) ."\n";
		return $statusArray;
	}

	/* GetVolume() 
	 * 
	 * Retrieves the mixer volume from the server.
     *
	 * NOTE: This function really should not be used. Instead, use $this->volume. The function
	 *   will most likely be deprecated in future releases.
	 */
	function GetVolume() {
		if ( $this->debugging ) echo "mpd->GetVolume()\n";
		$volLine = $this->SendCommand(MPD_CMD_STATUS);
		if ( ! $volLine ) {
			return NULL;
		} else {
			list ($vol) = sscanf($volLine,"volume: %d");
		}
		if ( $this->debugging ) echo "mpd->GetVolume() / return: $vol\n";
		return $vol;
	}

	/* GetPlaylist() 
	 * 
	 * Retrieves the playlist from the server and tosses it into a multidimensional array.
     *
	 * NOTE: This function really should not be used. Instead, use $this->playlist. The function
	 *   will most likely be deprecated in future releases.
	 */
	function GetPlaylist() {
		if ( $this->debugging ) echo "mpd->GetPlaylist()\n";
		$resp = $this->SendCommand(MPD_CMD_PLLIST);
		$playlist = $this->_parseFileListResponse($resp);
		if ( $this->debugging ) echo "mpd->GetPlaylist() / return ".print_r($playlist)."\n";
		return $playlist;
	}

    /* ----------------- Command compatibility tables --------------------- */
	var $COMPATIBILITY_MIN_TBL = array(
		MPD_CMD_SEEK 		=> "0.9.1"	,
		MPD_CMD_PLMOVE  	=> "0.9.1"	,
		MPD_CMD_RANDOM  	=> "0.9.1"	,
		MPD_CMD_PLSWAPTRACK	=> "0.9.1"	,
		MPD_CMD_PLMOVETRACK	=> "0.9.1"  ,
		MPD_CMD_PASSWORD	=> "0.10.0" ,
        MPD_CMD_SETVOL      => "0.10.0"
	);

    var $COMPATIBILITY_MAX_TBL = array(
        MPD_CMD_VOLUME      => "0.10.0"
    );

}   // ---------------------------- end of class ------------------------------


?>