* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id$
*/
abstract class Zend_Media_Id3_Frame extends Zend_Media_Id3_Object
{
/**
* This flag tells the tag parser what to do with this frame if it
* unknown and the tag is altered in any way. This applies to all kinds of
* alterations, including adding more padding and reordering the frames.
*/
const DISCARD_ON_TAGCHANGE = 16384;
/**
* This flag tells the tag parser what to do with this frame if it is
* unknown and the file, excluding the tag, is altered. This does not apply
* when the audio is completely replaced with other audio data.
*/
const DISCARD_ON_FILECHANGE = 8192;
/**
* This flag, if set, tells the software that the contents of this frame are
* intended to be read only. Changing the contents might break something,
* e.g. a signature.
*/
const READ_ONLY = 4096;
/**
* This flag indicates whether or not this frame belongs in a group with
* other frames. If set, a group identifier byte is added to the frame.
* Every frame with the same group identifier belongs to the same group.
*/
const GROUPING_IDENTITY = 32;
/**
* This flag indicates whether or not the frame is compressed. A Data
* Length Indicator byte is included in the frame.
*
* @see DATA_LENGTH_INDICATOR
*/
const COMPRESSION = 8;
/**
* This flag indicates whether or not the frame is encrypted. If set, one
* byte indicating with which method it was encrypted will be added to the
* frame. See description of the {@link Zend_Media_Id3_Frame_Encr ENCR}
* frame for more information about encryption method registration.
* Encryption should be done after compression. Whether or not setting this
* flag requires the presence of a Data Length Indicator depends on
* the specific algorithm used.
*
* @see DATA_LENGTH_INDICATOR
*/
const ENCRYPTION = 4;
/**
* This flag indicates whether or not unsynchronisation was applied to this
* frame.
*
* @since ID3v2.4.0
*/
const UNSYNCHRONISATION = 2;
/**
* This flag indicates that a data length indicator has been added to the
* frame.
*
* @since ID3v2.4.0
*/
const DATA_LENGTH_INDICATOR = 1;
/** @var integer */
private $_identifier;
/** @var integer */
private $_size = 0;
/** @var integer */
private $_flags = 0;
/**
* Constructs the class with given parameters and reads object related data
* from the ID3v2 tag.
*
* Replaces the reader instance with a string reader object instance that
* can be used to further process the data in the frame sub class.
*
* @todo Only limited subset of flags are processed.
* @param Zend_Io_Reader $reader The reader object.
* @param Array $options The options array.
*/
public function __construct($reader = null, &$options = array())
{
parent::__construct($reader, $options);
if ($reader === null) {
$this->_identifier = strtoupper(substr(get_class($this), -4));
} else {
$this->_identifier =
strtoupper($this->_reader->readString8(4, " "));
/* ID3v2.3.0 size and flags; convert flags to 2.4.0 format */
if ($this->getOption('version', 4) < 4) {
$this->_size = $this->_reader->readUInt32BE();
$flags = $this->_reader->readUInt16BE();
if (($flags & 0x8000) == 0x8000) {
$this->_flags |= self::DISCARD_ON_TAGCHANGE;
}
if (($flags & 0x4000) == 0x4000) {
$this->_flags |= self::DISCARD_ON_FILECHANGE;
}
if (($flags & 0x2000) == 0x2000) {
$this->_flags |= self::READ_ONLY;
}
if (($flags & 0x80) == 0x80) {
$this->_flags |= self::COMPRESSION;
}
if (($flags & 0x40) == 0x40) {
$this->_flags |= self::ENCRYPTION;
}
if (($flags & 0x20) == 0x20) {
$this->_flags |= self::GROUPING_IDENTITY;
}
}
/* ID3v2.4.0 size and flags */
else {
$this->_size =
$this->_decodeSynchsafe32($this->_reader->readUInt32BE());
$this->_flags = $this->_reader->readUInt16BE();
}
$dataLength = $this->_size;
if ($this->hasFlag(self::DATA_LENGTH_INDICATOR)) {
$dataLength =
$this->_decodeSynchsafe32($this->_reader->readUInt32BE());
$this->_size -= 4;
}
$data = $this->_reader->read($this->_size);
$this->_size = $dataLength;
if ($this->hasFlag(self::UNSYNCHRONISATION) ||
$this->getOption('unsynchronisation', false) === true) {
$data = $this->_decodeUnsynchronisation($data);
}
$this->_reader = new Zend_Io_StringReader($data);
}
}
/**
* Returns the frame identifier string.
*
* @return string
*/
public final function getIdentifier()
{
return $this->_identifier;
}
/**
* Sets the frame identifier.
*
* @param string $identifier The identifier.
*/
public final function setIdentifier($identifier)
{
$this->_identifier = $identifier;
}
/**
* Returns the size of the data in the final frame, after encryption,
* compression and unsynchronisation. The size is excluding the frame
* header.
*
* @return integer
*/
public final function getSize()
{
return $this->_size;
}
/**
* Checks whether or not the flag is set. Returns true if the
* flag is set, false otherwise.
*
* @param integer $flag The flag to query.
* @return boolean
*/
public final function hasFlag($flag)
{
return ($this->_flags & $flag) == $flag;
}
/**
* Returns the frame flags byte.
*
* @return integer
*/
public final function getFlags($flags)
{
return $this->_flags;
}
/**
* Sets the frame flags byte.
*
* @param string $flags The flags byte.
*/
public final function setFlags($flags)
{
$this->_flags = $flags;
}
/**
* Writes the frame raw data without the header.
*
* @param Zend_Io_Writer $writer The writer object.
* @return void
*/
abstract protected function _writeData($writer);
/**
* Writes the frame data with the header.
*
* @param Zend_Io_Writer $writer The writer object.
* @return void
*/
public function write($writer)
{
/* ID3v2.3.0 Flags; convert from 2.4.0 format */
if ($this->getOption('version', 4) < 4) {
$flags = 0;
if ($this->hasFlag(self::DISCARD_ON_TAGCHANGE)) {
$flags = $flags | 0x8000;
}
if ($this->hasFlag(self::DISCARD_ON_FILECHANGE)) {
$flags = $flags | 0x4000;
}
if ($this->hasFlag(self::READ_ONLY)) {
$flags = $flags | 0x2000;
}
if ($this->hasFlag(self::COMPRESSION)) {
$flags = $flags | 0x80;
}
if ($this->hasFlag(self::ENCRYPTION)) {
$flags = $flags | 0x40;
}
if ($this->hasFlag(self::GROUPING_IDENTITY)) {
$flags = $flags | 0x20;
}
}
/* ID3v2.4.0 Flags */
else {
$flags = $this->_flags;
}
$this->_writeData($buffer = new Zend_Io_StringWriter());
$data = $buffer->toString();
$size = $this->_size = strlen($data);
// ID3v2.4.0 supports frame level unsynchronisation. The corresponding
// option is set to true when any of the frames use the
// unsynchronisation scheme. The usage is denoted by
// Zend_Media_Id3_Header flag that is set accordingly upon file write.
if ($this->getOption('version', 4) >= 4) {
$data = $this->_encodeUnsynchronisation($data);
if (($dataLength = strlen($data)) != $size) {
$size = 4 + $dataLength;
$flags |= self::DATA_LENGTH_INDICATOR | self::UNSYNCHRONISATION;
$this->setOption('unsynchronisation', true);
} else {
$flags &= ~(self::DATA_LENGTH_INDICATOR |
self::UNSYNCHRONISATION);
}
}
$writer->writeString8(substr($this->_identifier, 0, 4), 4, " ")
->writeUInt32BE($this->getOption('version', 4) < 4 ? $size : $this->_encodeSynchsafe32($size))
->writeUInt16BE($flags);
if (($flags & self::DATA_LENGTH_INDICATOR) ==
self::DATA_LENGTH_INDICATOR) {
$writer->writeUInt32BE
($this->getOption('version', 4) < 4 ? $this->_size : $this->_encodeSynchsafe32($this->_size));
}
$writer->write($data);
}
}