Files
plibreader/src/ID3/ExtendedHeader.php
svollbehr 4b68a78dc8 Refactoring the code
git-svn-id: http://php-reader.googlecode.com/svn/trunk@140 51a70ab9-7547-0410-9469-37e369ee0574
2009-02-19 14:30:29 +00:00

325 lines
10 KiB
PHP

<?php
/**
* PHP Reader Library
*
* Copyright (c) 2008-2009 The PHP Reader Project Workgroup. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the project workgroup nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* @package php-reader
* @subpackage ID3
* @copyright Copyright (c) 2008-2009 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id$
*/
/**#@+ @ignore */
require_once("ID3/Object.php");
/**#@-*/
/**
* The extended header contains information that can provide further insight in
* the structure of the tag, but is not vital to the correct parsing of the tag
* information; hence the extended header is optional.
*
* @package php-reader
* @subpackage ID3
* @author Sven Vollbehr <svollbehr@gmail.com>
* @author Ryan Butterfield <buttza@gmail.com>
* @copyright Copyright (c) 2008-2009 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Rev$
*/
final class ID3_ExtendedHeader extends ID3_Object
{
/**
* A flag to denote that the present tag is an update of a tag found earlier
* in the present file or stream. If frames defined as unique are found in
* the present tag, they are to override any corresponding ones found in the
* earlier tag. This flag has no corresponding data.
*
* @since ID3v2.4.0
*/
const UPDATE = 64;
/**
* @since ID3v2.4.0 A flag to denote that a CRC-32 data is included in the
* extended header. The CRC is calculated on all the data between the header
* and footer as indicated by the header's tag length field, minus the
* extended header. Note that this includes the padding (if there is any), but
* excludes the footer. The CRC-32 is stored as an 35 bit synchsafe integer,
* leaving the upper four bits always zeroed.
*
* @since ID3v2.3.0 The CRC is calculated before unsynchronisation on the data
* between the extended header and the padding, i.e. the frames and only the
* frames.
*/
const CRC32 = 32;
/**
* A flag to denote whether or not the tag has restrictions applied on it.
*
* @since ID3v2.4.0
*/
const RESTRICTED = 16;
/** @var integer */
private $_size;
/** @var integer */
private $_flags = 0;
/** @var integer */
private $_padding;
/** @var integer */
private $_crc;
/** @var integer */
private $_restrictions = 0;
/**
* Constructs the class with given parameters and reads object related data
* from the ID3v2 tag.
*
* @param 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)
return;
$offset = $this->_reader->getOffset();
$this->_size = $this->_reader->readUInt32BE();
/* ID3v2.3.0 ExtendedHeader */
if ($this->getOption("version", 4) < 4) {
if ($this->_reader->readUInt16BE() == 0x8000)
$this->_flags = self::CRC32;
$this->_padding = $this->_reader->readUInt32BE();
if ($this->hasFlag(self::CRC32))
$this->_crc = Transform::readUInt32BE();
}
/* ID3v2.4.0 ExtendedHeader */
else {
$this->_size = $this->_decodeSynchsafe32($this->_size);
$this->_reader->skip(1);
$this->_flags = $this->_reader->readInt8();
if ($this->hasFlag(self::UPDATE))
$this->_reader->skip(1);
if ($this->hasFlag(self::CRC32)) {
$this->_reader->skip(1);
$this->_crc =
Transform::fromInt8($this->_reader->read(1)) * (0xfffffff + 1) +
_decodeSynchsafe32(Transform::fromUInt32BE($this->_reader->read(4)));
}
if ($this->hasFlag(self::RESTRICTED)) {
$this->_reader->skip(1);
$this->_restrictions = $this->_reader->readInt8(1);
}
}
}
/**
* Returns the extended header size in bytes.
*
* @return integer
*/
public function getSize() { return $this->_size; }
/**
* Checks whether or not the flag is set. Returns <var>true</var> if the flag
* is set, <var>false</var> otherwise.
*
* @param integer $flag The flag to query.
* @return boolean
*/
public function hasFlag($flag) { return ($this->_flags & $flag) == $flag; }
/**
* Returns the flags byte.
*
* @return integer
*/
public function getFlags($flags) { return $this->_flags; }
/**
* Sets the flags byte.
*
* @param integer $flags The flags byte.
*/
public function setFlags($flags) { $this->_flags = $flags; }
/**
* Returns the CRC-32 data.
*
* @return integer
*/
public function getCrc()
{
if ($this->hasFlag(self::CRC32))
return $this->_crc;
return false;
}
/**
* Sets whether the CRC-32 should be generated upon tag write.
*
* @param boolean $useCrc Whether CRC-32 should be generated.
*/
public function useCrc($useCrc)
{
if ($useCrc)
$this->setFlags($this->getFlags() | self::CRC32);
else
$this->setFlags($this->getFlags() & ~self::CRC32);
}
/**
* Sets the CRC-32. The CRC-32 value is calculated of all the frames in the
* tag and includes padding.
*
* @param integer $crc The 32-bit CRC value.
*/
public function setCrc($crc)
{
if (is_bool($crc))
$this->useCrc($crc);
else
$this->_crc = $crc;
}
/**
* Returns the restrictions. For some applications it might be desired to
* restrict a tag in more ways than imposed by the ID3v2 specification. Note
* that the presence of these restrictions does not affect how the tag is
* decoded, merely how it was restricted before encoding. If this flag is set
* the tag is restricted as follows:
*
* <pre>
* Restrictions %ppqrrstt
*
* p - Tag size restrictions
*
* 00 No more than 128 frames and 1 MB total tag size.
* 01 No more than 64 frames and 128 KB total tag size.
* 10 No more than 32 frames and 40 KB total tag size.
* 11 No more than 32 frames and 4 KB total tag size.
*
* q - Text encoding restrictions
*
* 0 No restrictions
* 1 Strings are only encoded with ISO-8859-1 or UTF-8.
*
* r - Text fields size restrictions
*
* 00 No restrictions
* 01 No string is longer than 1024 characters.
* 10 No string is longer than 128 characters.
* 11 No string is longer than 30 characters.
*
* Note that nothing is said about how many bytes is used to represent those
* characters, since it is encoding dependent. If a text frame consists of
* more than one string, the sum of the strungs is restricted as stated.
*
* s - Image encoding restrictions
*
* 0 No restrictions
* 1 Images are encoded only with PNG [PNG] or JPEG [JFIF].
*
* t - Image size restrictions
*
* 00 No restrictions
* 01 All images are 256x256 pixels or smaller.
* 10 All images are 64x64 pixels or smaller.
* 11 All images are exactly 64x64 pixels, unless required otherwise.
* </pre>
*
* @return integer
*/
public function getRestrictions() { return $this->_restrictions; }
/**
* Sets the restrictions byte. See {@link #getRestrictions} for more.
*
* @param integer $restrictions The restrictions byte.
*/
public function setRestrictions($restrictions)
{
$this->_restrictions = $restrictions;
}
/**
* Returns the total padding size, or simply the total tag size excluding the
* frames and the headers.
*
* @return integer
* @deprecated ID3v2.3.0
*/
public function getPadding() { return $this->_padding; }
/**
* Sets the total padding size, or simply the total tag size excluding the
* frames and the headers.
*
* @param integer $padding The padding size.
* @deprecated ID3v2.3.0
*/
public function setPadding($padding) { return $this->_padding = $padding; }
/**
* Returns the header data.
*
* @return string
*/
public function __toString()
{
/* ID3v2.3.0 ExtendedHeader */
if ($this->getOption("version", 4) < 4) {
return Transform::toUInt32BE($this->_size) .
Transform::toUInt16BE($this->hasFlag(self::CRC32) ? 0x8000 : 0) .
Transform::toUInt32BE($this->_padding) .
($this->hasFlag(self::CRC32) ? Transform::toUInt32BE($this->_crc) : "");
}
/* ID3v2.4.0 ExtendedHeader */
else {
return Transform::toUInt32BE($this->_encodeSynchsafe32($this->_size)) .
Transform::toInt8(1) . Transform::toInt8($this->_flags) .
($this->hasFlag(self::UPDATE) ? "\0" : "") .
($this->hasFlag(self::CRC32) ? Transform::toInt8(5) .
Transform::toInt8($this->_crc & 0xf0000000 >> 28 & 0xf /*eq >>> 28*/) .
Transform::toUInt32BE($this->_encodeSynchsafe32($this->_crc)) : "") .
($this->hasFlag(self::RESTRICTED) ?
Transform::toInt8(1) . Transform::toInt8($this->_restrictions) : "");
}
}
}