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Diffstat (limited to 'engines/scumm/cdda.cpp')
| -rw-r--r-- | engines/scumm/cdda.cpp | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/engines/scumm/cdda.cpp b/engines/scumm/cdda.cpp new file mode 100644 index 0000000000..adb414ecce --- /dev/null +++ b/engines/scumm/cdda.cpp @@ -0,0 +1,120 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +#include "scumm/cdda.h" +#include "common/stream.h" +#include "audio/audiostream.h" + +namespace Scumm { + + +#pragma mark - +#pragma mark --- CDDA stream --- +#pragma mark - + +#define START_OF_CDDA_DATA 800 +#define BLOCK_SIZE 1177 + +class CDDAStream : public Audio::SeekableAudioStream { +private: + Common::SeekableReadStream *_stream; + DisposeAfterUse::Flag _disposeAfterUse; + byte _shiftLeft; + byte _shiftRight; + uint32 _pos; + Audio::Timestamp _length; + +public: + CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse); + virtual ~CDDAStream(); + + int readBuffer(int16 *buffer, const int numSamples); + bool isStereo() const { return true; } + int getRate() const { return 44100; } + bool endOfData() const { return _stream->eos(); } + bool seek(const Audio::Timestamp &where); + Audio::Timestamp getLength() const { return _length; } +}; + +CDDAStream::CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse) : + _stream(stream), _disposeAfterUse(disposeAfterUse), _pos(START_OF_CDDA_DATA) { + _stream->seek(START_OF_CDDA_DATA, SEEK_SET); + // The total size of CDDA.SOU is 289,808,802 bytes or (289808802 - 800) / 1177 = 246226 blocks + // We also deduct the shift values to return the correct length + uint32 blocks = (_stream->size() - START_OF_CDDA_DATA) / BLOCK_SIZE; + _length = Audio::Timestamp(0, (_stream->size() - START_OF_CDDA_DATA - blocks) / (isStereo() ? 2 : 1), getRate()); +} + +CDDAStream::~CDDAStream() { + if (_disposeAfterUse == DisposeAfterUse::YES) + delete _stream; +} + +bool CDDAStream::seek(const Audio::Timestamp &where) { + const uint32 seekSample = convertTimeToStreamPos(where, getRate(), isStereo()).totalNumberOfFrames(); + uint32 blocks = seekSample / 1176; + + // Before seeking, read the shift values from the beginning of that block + _stream->seek(START_OF_CDDA_DATA + blocks * BLOCK_SIZE, SEEK_SET); + byte shiftVal = _stream->readByte(); + _shiftLeft = shiftVal >> 4; + _shiftRight = shiftVal & 0x0F; + + _pos = START_OF_CDDA_DATA + blocks + seekSample; + return _stream->seek(_pos, SEEK_SET); +} + +int CDDAStream::readBuffer(int16 *buffer, const int numSamples) { + int samples; + + for (samples = 0 ; samples < numSamples && !_stream->eos() ; ) { + if (!((_pos - START_OF_CDDA_DATA) % BLOCK_SIZE)) { + byte shiftVal = _stream->readByte(); + _shiftLeft = shiftVal >> 4; + _shiftRight = shiftVal & 0x0F; + _pos++; + } + buffer[samples++] = _stream->readSByte() << _shiftLeft; + buffer[samples++] = _stream->readSByte() << _shiftRight; + _pos += 2; + } + return samples; +} + +#pragma mark - +#pragma mark --- CDDA factory functions --- +#pragma mark - + +Audio::SeekableAudioStream *makeCDDAStream( + Common::SeekableReadStream *stream, + DisposeAfterUse::Flag disposeAfterUse) { + Audio::SeekableAudioStream *s = new CDDAStream(stream, disposeAfterUse); + if (s && s->endOfData()) { + delete s; + return 0; + } else { + return s; + } + return 0; +} + +} // End of namespace Scumm |