324 lines
8.2 KiB
C++
324 lines
8.2 KiB
C++
/***************************************************************************
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copyright : (C) 2002 - 2008 by Scott Wheeler
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email : wheeler@kde.org
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***************************************************************************/
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/***************************************************************************
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* This library is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU Lesser General Public License version *
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* 2.1 as published by the Free Software Foundation. *
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* *
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* This library is distributed in the hope that it will be useful, but *
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* WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
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* Lesser General Public License for more details. *
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* *
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* You should have received a copy of the GNU Lesser General Public *
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* License along with this library; if not, write to the Free Software *
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA *
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* 02110-1301 USA *
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* *
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* Alternatively, this file is available under the Mozilla Public *
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* License Version 1.1. You may obtain a copy of the License at *
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* http://www.mozilla.org/MPL/ *
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***************************************************************************/
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#include <stdlib.h>
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#include <bitset>
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#include <tstring.h>
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#include <tdebug.h>
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#include <taglib.h>
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#include "oggpageheader.h"
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#include "oggfile.h"
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using namespace TagLib;
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class Ogg::PageHeader::PageHeaderPrivate
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{
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public:
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PageHeaderPrivate(File *f, long pageOffset) :
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file(f),
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fileOffset(pageOffset),
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isValid(false),
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firstPacketContinued(false),
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lastPacketCompleted(false),
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firstPageOfStream(false),
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lastPageOfStream(false),
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absoluteGranularPosition(0),
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streamSerialNumber(0),
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pageSequenceNumber(-1),
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size(0),
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dataSize(0)
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{}
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File *file;
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long fileOffset;
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bool isValid;
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List<int> packetSizes;
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bool firstPacketContinued;
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bool lastPacketCompleted;
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bool firstPageOfStream;
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bool lastPageOfStream;
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long long absoluteGranularPosition;
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uint streamSerialNumber;
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int pageSequenceNumber;
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int size;
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int dataSize;
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};
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////////////////////////////////////////////////////////////////////////////////
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// public members
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////////////////////////////////////////////////////////////////////////////////
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Ogg::PageHeader::PageHeader(Ogg::File *file, long pageOffset)
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{
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d = new PageHeaderPrivate(file, pageOffset);
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if(file && pageOffset >= 0)
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read();
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}
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Ogg::PageHeader::~PageHeader()
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{
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delete d;
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}
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bool Ogg::PageHeader::isValid() const
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{
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return d->isValid;
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}
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List<int> Ogg::PageHeader::packetSizes() const
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{
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return d->packetSizes;
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}
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void Ogg::PageHeader::setPacketSizes(const List<int> &sizes)
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{
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d->packetSizes = sizes;
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}
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bool Ogg::PageHeader::firstPacketContinued() const
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{
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return d->firstPacketContinued;
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}
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void Ogg::PageHeader::setFirstPacketContinued(bool continued)
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{
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d->firstPacketContinued = continued;
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}
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bool Ogg::PageHeader::lastPacketCompleted() const
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{
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return d->lastPacketCompleted;
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}
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void Ogg::PageHeader::setLastPacketCompleted(bool completed)
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{
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d->lastPacketCompleted = completed;
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}
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bool Ogg::PageHeader::firstPageOfStream() const
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{
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return d->firstPageOfStream;
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}
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void Ogg::PageHeader::setFirstPageOfStream(bool first)
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{
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d->firstPageOfStream = first;
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}
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bool Ogg::PageHeader::lastPageOfStream() const
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{
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return d->lastPageOfStream;
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}
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void Ogg::PageHeader::setLastPageOfStream(bool last)
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{
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d->lastPageOfStream = last;
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}
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long long Ogg::PageHeader::absoluteGranularPosition() const
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{
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return d->absoluteGranularPosition;
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}
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void Ogg::PageHeader::setAbsoluteGranularPosition(long long agp)
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{
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d->absoluteGranularPosition = agp;
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}
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int Ogg::PageHeader::pageSequenceNumber() const
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{
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return d->pageSequenceNumber;
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}
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void Ogg::PageHeader::setPageSequenceNumber(int sequenceNumber)
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{
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d->pageSequenceNumber = sequenceNumber;
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}
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TagLib::uint Ogg::PageHeader::streamSerialNumber() const
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{
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return d->streamSerialNumber;
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}
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void Ogg::PageHeader::setStreamSerialNumber(uint n)
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{
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d->streamSerialNumber = n;
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}
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int Ogg::PageHeader::size() const
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{
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return d->size;
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}
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int Ogg::PageHeader::dataSize() const
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{
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return d->dataSize;
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}
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ByteVector Ogg::PageHeader::render() const
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{
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ByteVector data;
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// capture patern
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data.append("OggS");
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// stream structure version
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data.append(char(0));
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// header type flag
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std::bitset<8> flags;
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flags[0] = d->firstPacketContinued;
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flags[1] = d->pageSequenceNumber == 0;
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flags[2] = d->lastPageOfStream;
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data.append(char(flags.to_ulong()));
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// absolute granular position
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data.append(ByteVector::fromLongLong(d->absoluteGranularPosition, false));
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// stream serial number
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data.append(ByteVector::fromUInt(d->streamSerialNumber, false));
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// page sequence number
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data.append(ByteVector::fromUInt(d->pageSequenceNumber, false));
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// checksum -- this is left empty and should be filled in by the Ogg::Page
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// class
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data.append(ByteVector(4, 0));
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// page segment count and page segment table
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ByteVector pageSegments = lacingValues();
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data.append(char(uchar(pageSegments.size())));
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data.append(pageSegments);
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return data;
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}
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////////////////////////////////////////////////////////////////////////////////
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// private members
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////////////////////////////////////////////////////////////////////////////////
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void Ogg::PageHeader::read()
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{
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d->file->seek(d->fileOffset);
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// An Ogg page header is at least 27 bytes, so we'll go ahead and read that
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// much and then get the rest when we're ready for it.
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ByteVector data = d->file->readBlock(27);
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// Sanity check -- make sure that we were in fact able to read as much data as
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// we asked for and that the page begins with "OggS".
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if(data.size() != 27 || !data.startsWith("OggS")) {
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debug("Ogg::PageHeader::read() -- error reading page header");
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return;
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}
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std::bitset<8> flags(data[5]);
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d->firstPacketContinued = flags.test(0);
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d->firstPageOfStream = flags.test(1);
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d->lastPageOfStream = flags.test(2);
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d->absoluteGranularPosition = data.toLongLong(6, false);
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d->streamSerialNumber = data.toUInt(14, false);
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d->pageSequenceNumber = data.toUInt(18, false);
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// Byte number 27 is the number of page segments, which is the only variable
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// length portion of the page header. After reading the number of page
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// segments we'll then read in the corresponding data for this count.
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int pageSegmentCount = uchar(data[26]);
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ByteVector pageSegments = d->file->readBlock(pageSegmentCount);
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// Another sanity check.
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if(pageSegmentCount < 1 || int(pageSegments.size()) != pageSegmentCount)
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return;
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// The base size of an Ogg page 27 bytes plus the number of lacing values.
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d->size = 27 + pageSegmentCount;
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int packetSize = 0;
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for(int i = 0; i < pageSegmentCount; i++) {
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d->dataSize += uchar(pageSegments[i]);
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packetSize += uchar(pageSegments[i]);
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if(uchar(pageSegments[i]) < 255) {
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d->packetSizes.append(packetSize);
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packetSize = 0;
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}
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}
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if(packetSize > 0) {
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d->packetSizes.append(packetSize);
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d->lastPacketCompleted = false;
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}
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else
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d->lastPacketCompleted = true;
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d->isValid = true;
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}
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ByteVector Ogg::PageHeader::lacingValues() const
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{
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ByteVector data;
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List<int> sizes = d->packetSizes;
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for(List<int>::ConstIterator it = sizes.begin(); it != sizes.end(); ++it) {
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// The size of a packet in an Ogg page is indicated by a series of "lacing
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// values" where the sum of the values is the packet size in bytes. Each of
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// these values is a byte. A value of less than 255 (0xff) indicates the end
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// of the packet.
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div_t n = div(*it, 255);
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for(int i = 0; i < n.quot; i++)
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data.append(char(uchar(255)));
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if(it != --sizes.end() || d->lastPacketCompleted)
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data.append(char(uchar(n.rem)));
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}
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return data;
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}
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