/**
* Parse frame out from v2.3 and higher tags
*
* Frame ID $xx xx xx xx (four characters)
* Size $xx xx xx xx (32-bit integer in v2.3, 28-bit synchsafe in v2.4+)
* Flags $xx xx
*
* @param string $frameData
*/
protected function _getFrame($frameData)
{
$info = array();
// take next 10 bytes for header
$info['frameHeader'] = substr($frameData, 0, 10);
// and leave the rest in $frame_data
$info['frameData'] = substr($frameData, 10);
$info['frameName'] = substr($info['frameHeader'], 0, 4);
$info['frameSize'] = $this->_tagVersion == 3 ? Zend_Id3_ByteConvert::bigEndian2Int(substr($info['frameHeader'], 4, 4)) : Zend_Id3_ByteConvert::bigEndianSyncSafe2Int(substr($info['frameHeader'], 4, 4));
if ($info['frameSize'] < strlen($frameData) + 4) {
$arrBrokenMP3extFrames = array("" . 'MP3', "" . 'MP', ' MP3', 'MP3e');
$nextFrameID = substr($frameData, $info['frameSize'], 4);
if ($this->_isValidID3v2FrameName($nextFrameID)) {
// next frame is OK
} else {
if (in_array($info['frameName'], $arrBrokenMP3extFrames)) {
// MP3ext known broken frames - "ok" for the purposes of this test
} else {
if ($this->_tagVersion == 4 && $this->_isValidID3v2FrameName(substr($info['frameData'], Zend_Id3_ByteConvert::bigEndian2Int(substr($info['frameHeader'], 4, 4)), 4), 3)) {
$this->_tagVersion = 3;
$info['frameSize'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($info['frameHeader'], 4, 4));
// 32-bit integer
}
}
}
}
$info['frameFlag'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($info['frameHeader'], 8, 2));
// padding encountered
if ($info['frameName'] == "") {
return $this->_parsePadding($info['frameData'], $info['frameHeader']);
}
return $info;
}
public static function littleEndian2Float($byte_word)
{
return Zend_Id3_ByteConvert::bigEndian2Float(strrev($byte_word));
}
/**
* Parse the Frame Flags
*
* @return array
* @throws Zend_Id3_Adapter_Id3v2_Frame_Exception
*/
private function _parseFrameFlags()
{
$flags = array();
switch ($this->_tagVersion) {
/**
* v2.3 Frame Header Flags
* %abc00000 %ijk00000
*/
case 3:
$flags['TagAlterPreservation'] = (bool) ($this->_data['frame_flags_raw'] & 0x8000);
// a - Tag alter preservation
$flags['FileAlterPreservation'] = (bool) ($this->_data['frame_flags_raw'] & 0x4000);
// b - File alter preservation
$flags['ReadOnly'] = (bool) ($this->_data['frame_flags_raw'] & 0x2000);
// c - Read only
$flags['compression'] = (bool) ($this->_data['frame_flags_raw'] & 0x80);
// i - Compression
$flags['Encryption'] = (bool) ($this->_data['frame_flags_raw'] & 0x40);
// j - Encryption
$flags['GroupingIdentity'] = (bool) ($this->_data['frame_flags_raw'] & 0x20);
// k - Grouping identity
break;
/**
* v2.4 Frame Header Flags
* %0abc0000 %0h00kmnp
*/
/**
* v2.4 Frame Header Flags
* %0abc0000 %0h00kmnp
*/
case 4:
$flags['TagAlterPreservation'] = (bool) ($this->_data['frame_flags_raw'] & 0x4000);
// a - Tag alter preservation
$flags['FileAlterPreservation'] = (bool) ($this->_data['frame_flags_raw'] & 0x2000);
// b - File alter preservation
$flags['ReadOnly'] = (bool) ($this->_data['frame_flags_raw'] & 0x1000);
// c - Read only
$flags['GroupingIdentity'] = (bool) ($this->_data['frame_flags_raw'] & 0x40);
// h - Grouping identity
$flags['compression'] = (bool) ($this->_data['frame_flags_raw'] & 0x8);
// k - Compression
$flags['Encryption'] = (bool) ($this->_data['frame_flags_raw'] & 0x4);
// m - Encryption
$flags['Unsynchronisation'] = (bool) ($this->_data['frame_flags_raw'] & 0x2);
// n - Unsynchronisation
$flags['DataLengthIndicator'] = (bool) ($this->_data['frame_flags_raw'] & 0x1);
// p - Data length indicator
// Frame-level de-unsynchronisation - ID3v2.4
if ($flags['Unsynchronisation']) {
$this->_data['data'] = str_replace("ÿ", "ÿ", $this->_data['data']);
}
break;
}
/**
* Frame-Level de-compression
*/
if ($flags['compression']) {
$this->_data['decompressed_size'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($this->_data['data'], 0, 4));
if (!function_exists('gzuncompress')) {
include_once 'Zend/Id3/Adapter/Id3v2/Frame/Exception.php';
throw new Zend_Id3_Adapter_Id3v2_Frame_Exception('gzuncompress() support required to decompress ID3v2 frame "' . $this->_data['frame_name'] . '"');
} elseif ($decompressed_data = @gzuncompress(substr($this->_data['data'], 4))) {
$this->_data['data'] = $decompressed_data;
} else {
include_once 'Zend/Id3/Adapter/Id3v2/Frame/Exception.php';
throw new Zend_Id3_Adapter_Id3v2_Frame_Exception('gzuncompress() failed on compressed contents of ID3v2 frame "' . $this->_data['frame_name'] . '"');
}
}
return $flags;
}
/**
*
*/
protected function _proccessExtendedFrameHeader($frameData)
{
$extendedHeaderOffset = 0;
switch ($this->_tagMajorVersion) {
/**
* v2.3 definition:
*
* Extended header size $xx xx xx xx // 32-bit integer
* Extended Flags $xx xx
* %x0000000 %00000000 // v2.3
* x - CRC data present
* Size of padding $xx xx xx xx
*/
case 3:
$this->_tagInfo['id3v2']['exthead']['length'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 4), 0);
$extendedHeaderOffset += 4;
$this->_tagInfo['id3v2']['exthead']['flag_bytes'] = 2;
$this->_tagInfo['id3v2']['exthead']['flag_raw'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, $this->_tagInfo['id3v2']['exthead']['flag_bytes']));
$extendedHeaderOffset += $this->_tagInfo['id3v2']['exthead']['flag_bytes'];
$this->_tagInfo['id3v2']['exthead']['flags']['crc'] = (bool) ($this->_tagInfo['id3v2']['exthead']['flag_raw'] & 0x8000);
$this->_tagInfo['id3v2']['exthead']['padding_size'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 4));
$extendedHeaderOffset += 4;
if ($this->_tagInfo['id3v2']['exthead']['flags']['crc']) {
$this->_tagInfo['id3v2']['exthead']['flag_data']['crc'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 4));
$extendedHeaderOffset += 4;
}
$extendedHeaderOffset += $this->_tagInfo['id3v2']['exthead']['padding_size'];
break;
/**
* v2.4 definition:
*
* Extended header size 4 * %0xxxxxxx * 28-bit synchsafe integer
* Number of flag bytes $01
* Extended Flags $xx
* %0bcd0000 * v2.4
* b - Tag is an update
* Flag data length $00
* c - CRC data present
* Flag data length $05
* Total frame CRC 5 * %0xxxxxxx
* d - Tag restrictions
* Flag data length $01
*/
/**
* v2.4 definition:
*
* Extended header size 4 * %0xxxxxxx * 28-bit synchsafe integer
* Number of flag bytes $01
* Extended Flags $xx
* %0bcd0000 * v2.4
* b - Tag is an update
* Flag data length $00
* c - CRC data present
* Flag data length $05
* Total frame CRC 5 * %0xxxxxxx
* d - Tag restrictions
* Flag data length $01
*/
case 4:
$this->_tagInfo['id3v2']['exthead']['length'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 4), 1);
$extendedHeaderOffset += 4;
$this->_tagInfo['id3v2']['exthead']['flag_bytes'] = 1;
$this->_tagInfo['id3v2']['exthead']['flag_raw'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, $this->_tagInfo['id3v2']['exthead']['flag_bytes']));
$extendedHeaderOffset += $this->_tagInfo['id3v2']['exthead']['flag_bytes'];
$this->_tagInfo['id3v2']['exthead']['flags']['update'] = (bool) ($this->_tagInfo['id3v2']['exthead']['flag_raw'] & 0x4000);
$this->_tagInfo['id3v2']['exthead']['flags']['crc'] = (bool) ($this->_tagInfo['id3v2']['exthead']['flag_raw'] & 0x2000);
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions'] = (bool) ($this->_tagInfo['id3v2']['exthead']['flag_raw'] & 0x1000);
if ($this->_tagInfo['id3v2']['exthead']['flags']['crc']) {
$this->_tagInfo['id3v2']['exthead']['flag_data']['crc'] = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 5), 1);
$extendedHeaderOffset += 5;
}
if ($this->_tagInfo['id3v2']['exthead']['flags']['restrictions']) {
// %ppqrrstt
$restrictionsByte = Zend_Id3_ByteConvert::bigEndian2Int(substr($frameData, $extendedHeaderOffset, 1));
$extendedHeaderOffset += 1;
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions']['tagsize'] = ($restrictionsByte && 0xc0) >> 6;
// p - Tag size restrictions
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions']['textenc'] = ($restrictionsByte && 0x20) >> 5;
// q - Text encoding restrictions
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions']['textsize'] = ($restrictionsByte && 0x18) >> 3;
// r - Text fields size restrictions
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions']['imgenc'] = ($restrictionsByte && 0x4) >> 2;
// s - Image encoding restrictions
$this->_tagInfo['id3v2']['exthead']['flags']['restrictions']['imgsize'] = ($restrictionsByte && 0x3) >> 0;
// t - Image size restrictions
}
break;
}
$this->_frameDataOffset += $extendedHeaderOffset;
$frameData = substr($frameData, $extendedHeaderOffset);
return $frameData;
}