getid3_id3v2

22class getid3_id3v2 extends getid3_handler23{24	public $StartingOffset = 0;25 26	/**27	 * @return bool28	 */29	public function Analyze() {30		$info = &$this->getid3->info;31 32		//    Overall tag structure:33		//        +-----------------------------+34		//        |      Header (10 bytes)      |35		//        +-----------------------------+36		//        |       Extended Header       |37		//        | (variable length, OPTIONAL) |38		//        +-----------------------------+39		//        |   Frames (variable length)  |40		//        +-----------------------------+41		//        |           Padding           |42		//        | (variable length, OPTIONAL) |43		//        +-----------------------------+44		//        | Footer (10 bytes, OPTIONAL) |45		//        +-----------------------------+46 47		//    Header48		//        ID3v2/file identifier      "ID3"49		//        ID3v2 version              $04 0050		//        ID3v2 flags                (%ab000000 in v2.2, %abc00000 in v2.3, %abcd0000 in v2.4.x)51		//        ID3v2 size             4 * %0xxxxxxx52 53 54		// shortcuts55		$info['id3v2']['header'] = true;56		$thisfile_id3v2                  = &$info['id3v2'];57		$thisfile_id3v2['flags']         =  array();58		$thisfile_id3v2_flags            = &$thisfile_id3v2['flags'];59 60 61		$this->fseek($this->StartingOffset);62		$header = $this->fread(10);63		if (substr($header, 0, 3) == 'ID3'  &&  strlen($header) == 10) {64 65			$thisfile_id3v2['majorversion'] = ord($header[3]);66			$thisfile_id3v2['minorversion'] = ord($header[4]);67 68			// shortcut69			$id3v2_majorversion = &$thisfile_id3v2['majorversion'];70 71		} else {72 73			unset($info['id3v2']);74			return false;75 76		}77 78		if ($id3v2_majorversion > 4) { // this script probably won't correctly parse ID3v2.5.x and above (if it ever exists)79 80			$this->error('this script only parses up to ID3v2.4.x - this tag is ID3v2.'.$id3v2_majorversion.'.'.$thisfile_id3v2['minorversion']);81			return false;82 83		}84 85		$id3_flags = ord($header[5]);86		switch ($id3v2_majorversion) {87			case 2:88				// %ab000000 in v2.289				$thisfile_id3v2_flags['unsynch']     = (bool) ($id3_flags & 0x80); // a - Unsynchronisation90				$thisfile_id3v2_flags['compression'] = (bool) ($id3_flags & 0x40); // b - Compression91				break;92 93			case 3:94				// %abc00000 in v2.395				$thisfile_id3v2_flags['unsynch']     = (bool) ($id3_flags & 0x80); // a - Unsynchronisation96				$thisfile_id3v2_flags['exthead']     = (bool) ($id3_flags & 0x40); // b - Extended header97				$thisfile_id3v2_flags['experim']     = (bool) ($id3_flags & 0x20); // c - Experimental indicator98				break;99 100			case 4:101				// %abcd0000 in v2.4