5ab1bb40f6
git-svn-id: http://php-reader.googlecode.com/svn/trunk@108 51a70ab9-7547-0410-9469-37e369ee0574
186 lines
7.5 KiB
PHP
186 lines
7.5 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 ASF
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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("ASF/Object.php");
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/**#@-*/
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/**
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* This top-level ASF object supplies the necessary indexing information for an
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* ASF file that contains more than just a plain script-audio-video combination.
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* It includes stream-specific indexing information based on an adjustable index
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* entry time interval. The index is designed to be broken into blocks to
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* facilitate storage that is more space-efficient by using 32-bit offsets
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* relative to a 64-bit base. That is, each index block has a full 64-bit offset
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* in the block header that is added to the 32-bit offsets found in each index
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* entry. If a file is larger than 2^32 bytes, then multiple index blocks can be
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* used to fully index the entire large file while still keeping index entry
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* offsets at 32 bits.
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*
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* Indices into the <i>Index Object</i> are in terms of presentation times. The
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* corresponding <i>Offset</i> field values of the <i>Index Entry</i> byte
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* offsets that, when combined with the <i>Block Position</i> value of the
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* <i>Index Block</i>, indicate the starting location in bytes of an ASF Data
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* Packet relative to the start of the first ASF Data Packet in the file.
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*
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* An offset value of 0xFFFFFFFF is used to indicate an invalid offset value.
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* Invalid offsets signify that this particular index entry does not identify a
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* valid indexible point. Invalid offsets may occur for the initial index
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* entries of a digital media stream whose first ASF Data Packet has a non-zero
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* send time. Invalid offsets may also occur in the case where a digital media
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* stream has a large gap in the presentation time of successive objects.
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*
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* The <i>Index Object</i> is not recommended for use with files where the
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* <i>Send Time</i> of the first <i>Data Packet</i> within the <i>Data
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* Object</i> has a <i>Send Time</i> value significantly greater than zero
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* (otherwise the index itself will be sparse and inefficient).
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*
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* Any ASF file containing an <i>Index Object</i> does also contain an <i>Index
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* Parameters Object</i> in its {@link ASF_Object_Header ASF Header}.
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*
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* @package php-reader
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* @subpackage ASF
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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 ASF_Object_Index extends ASF_Object
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{
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/**
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* Indicates that the index type is Nearest Past Data Packet. The Nearest
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* Past Data Packet indexes point to the data packet whose presentation time
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* is closest to the index entry time.
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*/
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const NEAREST_PAST_DATA_PACKET = 1;
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/**
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* Indicates that the index type is Nearest Past Media. The Nearest Past
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* Object indexes point to the closest data packet containing an entire object
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* or first fragment of an object.
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*/
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const NEAREST_PAST_MEDIA = 2;
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/**
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* Indicates that the index type is Nearest Past Cleanpoint. The Nearest Past
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* Cleanpoint indexes point to the closest data packet containing an entire
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* object (or first fragment of an object) that has the Cleanpoint Flag set.
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*
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* Nearest Past Cleanpoint is the most common type of index.
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*/
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const NEAREST_PAST_CLEANPOINT = 3;
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/** @var integer */
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private $_indexEntryTimeInterval;
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/** @var Array */
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private $_indexSpecifiers = array();
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/** @var Array */
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private $_indexBlocks = array();
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/**
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* Constructs the class with given parameters and reads object related data
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* from the ASF file.
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*
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* @param Reader $reader The reader object.
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* @param Array $options The options array.
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*/
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public function __construct($reader, &$options = array())
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{
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parent::__construct($reader, $options);
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$this->_indexEntryTimeInterval = $this->_reader->readUInt32LE();
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$indexSpecifiersCount = $this->_reader->readUInt16LE();
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$indexBlocksCount = $this->_reader->readUInt32LE();
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for ($i = 0; $i < $indexSpecifiersCount; $i++)
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$this->_indexSpecifiers[] = array
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("streamNumber" => $this->_reader->readUInt16LE(),
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"indexType" => $this->_reader->readUInt16LE());
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for ($i = 0; $i < $indexBlocksCount; $i++) {
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$indexEntryCount = $this->_reader->readUInt32LE();
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$blockPositions = array();
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for ($i = 0; $i < $indexSpecifiersCount; $i++)
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$blockPositions[] = $this->_reader->readInt64LE();
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$offsets = array();
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for ($i = 0; $i < $indexSpecifiersCount; $i++)
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$offsets[] = $this->_reader->readUInt32LE();
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$this->_indexBlocks[] = array
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("blockPositions" => $blockPositions,
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"indexEntryOffsets" => $offsets);
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}
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}
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/**
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* Returns the time interval between each index entry in ms.
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*
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* @return integer
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*/
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public function getIndexEntryTimeInterval()
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{
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return $this->_indexEntryTimeInterval;
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}
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/**
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* Returns an array of index specifiers. Each entry consists of the following
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* keys.
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*
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* o streamNumber -- Specifies the stream number that the <i>Index
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* Specifiers</i> refer to. Valid values are between 1 and 127.
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*
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* o indexType -- Specifies the type of index.
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*
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* @return Array
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*/
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public function getIndexSpecifiers() { return $this->_indexSpecifiers; }
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/**
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* Returns an array of index entries. Each entry consists of the following
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* keys.
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*
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* o blockPositions -- Specifies a list of byte offsets of the beginnings of
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* the blocks relative to the beginning of the first Data Packet (for
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* example, the beginning of the Data Object + 50 bytes).
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*
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* o indexEntryOffsets -- Specifies the offset. An offset value of
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* 0xffffffff indicates an invalid offset value.
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*
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* @return Array
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*/
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public function getIndexBlocks() { return $this->_indexBlocks; }
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}
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