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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: ASPI.php 75 2008-04-14 23:57:21Z svollbehr $
* @since ID3v2.4.0
*/
/**#@+ @ignore */
require_once("ID3/Frame.php");
/**#@-*/
/**
* Audio files with variable bit rates are intrinsically difficult to deal with
* in the case of seeking within the file. The <i>Audio seek point index</i> or
* ASPI frame makes seeking easier by providing a list a seek points within the
* audio file. The seek points are a fractional offset within the audio data,
* providing a starting point from which to find an appropriate point to start
* decoding. The presence of an ASPI frame requires the existence of a
* {@link ID3_Frame_TLEN} frame, indicating the duration of the file in
* milliseconds. There may only be one audio seek point index frame in a tag.
*
* @todo Data parsing and write support
* @package php-reader
* @subpackage ID3
* @author Sven Vollbehr <svollbehr@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: 75 $
* @since ID3v2.4.0
*/
final class ID3_Frame_ASPI extends ID3_Frame
{
/** @var integer */
private $_dataStart;
/** @var integer */
private $_dataLength;
/** @var integer */
private $_size;
/** @var Array */
private $_fractions = array();
/**
* 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)
throw new ID3_Exception("Write not supported yet");
$this->_dataStart = Transform::fromInt32BE(substr($this->_data, 0, 4));
$this->_dataLength = Transform::fromInt32BE(substr($this->_data, 4, 4));
$this->_size = Transform::fromInt16BE(substr($this->_data, 8, 2));
$bitsPerPoint = Transform::fromInt8($this->_data[10]);
/*for ($i = 0, $offset = 11; $i < $this->_size; $i++) {
if ($bitsPerPoint == 16) {
$this->_fractions[$i] = substr($this->_data, $offset, 2);
$offset += 2;
} else {
$this->_fractions[$i] = substr($this->_data, $offset, 1);
$offset ++;
}
}*/
}
/**
* Returns the byte offset from the beginning of the file.
*
* @return integer
*/
public function getDataStart() { return $this->_dataStart; }
/**
* Sets the byte offset from the beginning of the file.
*
* @param integer $dataStart The offset.
*/
public function setDataStart($dataStart) { $this->_dataStart = $dataStart; }
/**
* Returns the byte length of the audio data being indexed.
*
* @return integer
*/
public function getDataLength() { return $this->_dataLength; }
/**
* Sets the byte length of the audio data being indexed.
*
* @param integer $dataLength The length.
*/
public function setDataLength($dataLength)
{
$this->_dataLength = $dataLength;
}
/**
* Returns the number of index points in the frame.
*
* @return integer
*/
public function getSize() { return count($this->_fractions); }
/**
* Returns the numerator of the fraction representing a relative position in
* the data or <var>false</var> if index not defined. The denominator is 2
* to the power of b.
*
* @param integer $index The fraction numerator.
* @return integer
*/
public function getFractionAt($index)
{
if (isset($this->_fractions[$index]))
return $this->_fractions[$index];
return false;
}
}
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