<?php
  /////////////////////////////////////////////////////////////////
  /// getID3() by James Heinrich <info@getid3.org>               //
  //  available at http://getid3.sourceforge.net                 //
  //            or http://www.getid3.org                         //

  //          also https://github.com/JamesHeinrich/getID3       //

  /////////////////////////////////////////////////////////////////
  // See readme.txt for more details                             //
  /////////////////////////////////////////////////////////////////
  //                                                             //
  // module.audio.mod.php                                        //
  // module for analyzing MOD Audio files                        //
  // dependencies: NONE                                          //
  //                                                            ///
  /////////////////////////////////////////////////////////////////
  
  
  class getid3_mod extends getid3_handler
  {

  	public function Analyze() {

  		$info = &$this->getid3->info;

  		$this->fseek($info['avdataoffset']);
  		$fileheader = $this->fread(1088);

  		if (preg_match('#^IMPM#', $fileheader)) {
  			return $this->getITheaderFilepointer();
  		} elseif (preg_match('#^Extended Module#', $fileheader)) {
  			return $this->getXMheaderFilepointer();
  		} elseif (preg_match('#^.{44}SCRM#', $fileheader)) {
  			return $this->getS3MheaderFilepointer();
  		} elseif (preg_match('#^.{1080}(M\\.K\\.|M!K!|FLT4|FLT8|[5-9]CHN|[1-3][0-9]CH)#', $fileheader)) {
  			return $this->getMODheaderFilepointer();
  		}
  		$info['error'][] = 'This is not a known type of MOD file';
  		return false;
  	}

  	public function getMODheaderFilepointer() {

  		$info = &$this->getid3->info;

  		$this->fseek($info['avdataoffset'] + 1080);
  		$FormatID = $this->fread(4);

  		if (!preg_match('#^(M.K.|[5-9]CHN|[1-3][0-9]CH)$#', $FormatID)) {
  			$info['error'][] = 'This is not a known type of MOD file';
  			return false;
  		}
  
  		$info['fileformat'] = 'mod';
  
  		$info['error'][] = 'MOD parsing not enabled in this version of getID3() ['.$this->getid3->version().']';
  		return false;
  	}

  	public function getXMheaderFilepointer() {

  		$info = &$this->getid3->info;

  		$this->fseek($info['avdataoffset']);
  		$FormatID = $this->fread(15);

  		if (!preg_match('#^Extended Module$#', $FormatID)) {
  			$info['error'][] = 'This is not a known type of XM-MOD file';
  			return false;
  		}
  
  		$info['fileformat'] = 'xm';
  
  		$info['error'][] = 'XM-MOD parsing not enabled in this version of getID3() ['.$this->getid3->version().']';
  		return false;
  	}

  	public function getS3MheaderFilepointer() {

  		$info = &$this->getid3->info;

  		$this->fseek($info['avdataoffset'] + 44);
  		$FormatID = $this->fread(4);

  		if (!preg_match('#^SCRM$#', $FormatID)) {
  			$info['error'][] = 'This is not a ScreamTracker MOD file';
  			return false;
  		}
  
  		$info['fileformat'] = 's3m';
  
  		$info['error'][] = 'ScreamTracker parsing not enabled in this version of getID3() ['.$this->getid3->version().']';
  		return false;
  	}

  	public function getITheaderFilepointer() {

  		$info = &$this->getid3->info;

  		$this->fseek($info['avdataoffset']);
  		$FormatID = $this->fread(4);

  		if (!preg_match('#^IMPM$#', $FormatID)) {
  			$info['error'][] = 'This is not an ImpulseTracker MOD file';
  			return false;
  		}
  
  		$info['fileformat'] = 'it';
  
  		$info['error'][] = 'ImpulseTracker parsing not enabled in this version of getID3() ['.$this->getid3->version().']';
  		return false;
  	}
  
  }