1182f0e0ff
git-svn-id: http://php-reader.googlecode.com/svn/trunk@39 51a70ab9-7547-0410-9469-37e369ee0574
127 lines
4.8 KiB
PHP
127 lines
4.8 KiB
PHP
<?php
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/**
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* PHP Reader Library
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*
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* Copyright (c) 2008 The PHP Reader Project Workgroup. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* - Neither the name of the project workgroup nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* @package php-reader
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* @subpackage ID3
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* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
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* @license http://code.google.com/p/php-reader/wiki/License New BSD License
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* @version $Id$
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*/
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/**#@+ @ignore */
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require_once("ID3/Frame.php");
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/**#@-*/
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/**
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* Sometimes the server from which an audio file is streamed is aware of
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* transmission or coding problems resulting in interruptions in the audio
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* stream. In these cases, the size of the buffer can be recommended by the
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* server using the <i>Recommended buffer size</i> frame. If the embedded info
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* flag is set then this indicates that an ID3 tag with the maximum size
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* described in buffer size may occur in the audio stream. In such case the tag
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* should reside between two MPEG frames, if the audio is MPEG encoded. If the
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* position of the next tag is known, offset to next tag may be used. The offset
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* is calculated from the end of tag in which this frame resides to the first
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* byte of the header in the next. This field may be omitted. Embedded tags are
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* generally not recommended since this could render unpredictable behaviour
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* from present software/hardware.
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*
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* For applications like streaming audio it might be an idea to embed tags into
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* the audio stream though. If the clients connects to individual connections
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* like HTTP and there is a possibility to begin every transmission with a tag,
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* then this tag should include a recommended buffer size frame. If the client
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* is connected to a arbitrary point in the stream, such as radio or multicast,
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* then the recommended buffer size frame should be included in every tag.
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*
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* The buffer size should be kept to a minimum. There may only be one "RBUF"
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* frame in each tag.
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*
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* @package php-reader
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* @subpackage ID3
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* @author Sven Vollbehr <svollbehr@gmail.com>
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* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
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* @license http://code.google.com/p/php-reader/wiki/License New BSD License
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* @version $Rev$
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*/
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final class ID3_Frame_RBUF extends ID3_Frame
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{
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/**
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* A flag to denote that an ID3 tag with the maximum size described in buffer
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* size may occur in the audio stream.
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*/
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const EMBEDDED = 0x1;
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/** @var integer */
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private $_size;
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/** @var integer */
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private $_flags;
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/** @var integer */
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private $_offset;
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/**
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* Constructs the class with given parameters and parses object related data.
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*
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* @param Reader $reader The reader object.
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*/
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public function __construct($reader)
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{
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parent::__construct($reader);
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$this->_size = Transform::fromInt32BE(substr($this->_data, 0, 3));
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$this->_flags = substr($this->_data, 3, 1);
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$this->_offset = Transform::fromInt32BE(substr($this->_data, 4, 4));
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}
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/**
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* Returns the buffer size.
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*
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* @return integer
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*/
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public function getSize() { return $this->_size; }
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/**
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* Checks whether or not the flag is set. Returns <var>true</var> if the flag
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* is set, <var>false</var> otherwise.
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*
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* @param integer $flag The flag to query.
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* @return boolean
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*/
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public function hasFlag($flag) { return ($this->_flags & $flag) == $flag; }
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/**
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* Returns the offset to next tag.
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*
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* @return integer
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*/
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public function getOffset() { return $this->_size; }
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}
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