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<?php
/**
* PHP Reader Library
*
* Copyright (c) 2008 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 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id: RBUF.php 105 2008-07-30 14:56:47Z svollbehr $
*/
/**#@+ @ignore */
require_once("ID3/Frame.php");
/**#@-*/
/**
* Sometimes the server from which an audio file is streamed is aware of
* transmission or coding problems resulting in interruptions in the audio
* stream. In these cases, the size of the buffer can be recommended by the
* server using the <i>Recommended buffer size</i> frame. If the embedded info
* flag is set then this indicates that an ID3 tag with the maximum size
* described in buffer size may occur in the audio stream. In such case the tag
* should reside between two MPEG frames, if the audio is MPEG encoded. If the
* position of the next tag is known, offset to next tag may be used. The offset
* is calculated from the end of tag in which this frame resides to the first
* byte of the header in the next. This field may be omitted. Embedded tags are
* generally not recommended since this could render unpredictable behaviour
* from present software/hardware.
*
* For applications like streaming audio it might be an idea to embed tags into
* the audio stream though. If the clients connects to individual connections
* like HTTP and there is a possibility to begin every transmission with a tag,
* then this tag should include a recommended buffer size frame. If the client
* is connected to a arbitrary point in the stream, such as radio or multicast,
* then the recommended buffer size frame should be included in every tag.
*
* The buffer size should be kept to a minimum. There may only be one RBUF
* frame in each tag.
*
* @package php-reader
* @subpackage ID3
* @author Sven Vollbehr <svollbehr@gmail.com>
* @author Ryan Butterfield <buttza@gmail.com>
* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Rev: 105 $
*/
final class ID3_Frame_RBUF extends ID3_Frame
{
/**
* A flag to denote that an ID3 tag with the maximum size described in buffer
* size may occur in the audio stream.
*/
const EMBEDDED = 0x1;
/** @var integer */
private $_bufferSize;
/** @var integer */
private $_infoFlags;
/** @var integer */
private $_offset = 0;
/**
* Constructs the class with given parameters and parses object related data.
*
* @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;
$this->_bufferSize =
Transform::fromUInt32BE("\0" . substr($this->_data, 0, 3));
$this->_infoFlags = Transform::fromInt8($this->_data[3]);
if ($this->getSize() > 4)
$this->_offset = Transform::fromInt32BE(substr($this->_data, 4, 4));
}
/**
* Returns the buffer size.
*
* @return integer
*/
public function getBufferSize() { return $this->_bufferSize; }
/**
* Sets the buffer size.
*
* @param integer $size The buffer size.
*/
public function setBufferSize($bufferSize)
{
$this->_bufferSize = $bufferSize;
}
/**
* Checks whether or not the flag is set. Returns <var>true</var> if the flag
* is set, <var>false</var> otherwise.
*
* @param integer $flag The flag to query.
* @return boolean
*/
public function hasInfoFlag($flag)
{
return ($this->_infoFlags & $flag) == $flag;
}
/**
* Returns the flags byte.
*
* @return integer
*/
public function getInfoFlags() { return $this->_infoFlags; }
/**
* Sets the flags byte.
*
* @param string $flags The flags byte.
*/
public function setInfoFlags($infoFlags) { $this->_infoFlags = $infoFlags; }
/**
* Returns the offset to next tag.
*
* @return integer
*/
public function getOffset() { return $this->_offset; }
/**
* Sets the offset to next tag.
*
* @param integer $offset The offset.
*/
public function setOffset($offset) { $this->_offset = $offset; }
/**
* Returns the frame raw data.
*
* @return string
*/
public function __toString()
{
$this->setData
(substr(Transform::toUInt32BE($this->_bufferSize), 1, 3) .
Transform::toInt8($this->_infoFlags) .
Transform::toInt32BE($this->_offset));
return parent::__toString();
}
}
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