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https://github.com/libretro/scummvm.git
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120 lines
3.8 KiB
C++
120 lines
3.8 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "scumm/cdda.h"
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#include "common/stream.h"
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#include "audio/audiostream.h"
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namespace Scumm {
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#pragma mark -
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#pragma mark --- CDDA stream ---
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#pragma mark -
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#define START_OF_CDDA_DATA 800
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#define BLOCK_SIZE 1177
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class CDDAStream : public Audio::SeekableAudioStream {
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private:
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Common::SeekableReadStream *_stream;
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DisposeAfterUse::Flag _disposeAfterUse;
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byte _shiftLeft;
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byte _shiftRight;
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uint32 _pos;
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Audio::Timestamp _length;
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public:
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CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse);
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~CDDAStream() override;
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int readBuffer(int16 *buffer, const int numSamples) override;
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bool isStereo() const override { return true; }
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int getRate() const override { return 44100; }
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bool endOfData() const override { return _stream->eos(); }
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bool seek(const Audio::Timestamp &where) override;
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Audio::Timestamp getLength() const override { return _length; }
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};
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CDDAStream::CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse) :
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_stream(stream), _disposeAfterUse(disposeAfterUse), _pos(START_OF_CDDA_DATA) {
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_stream->seek(START_OF_CDDA_DATA, SEEK_SET);
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// The total size of CDDA.SOU is 289,808,802 bytes or (289808802 - 800) / 1177 = 246226 blocks
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// We also deduct the shift values to return the correct length
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uint32 blocks = (_stream->size() - START_OF_CDDA_DATA) / BLOCK_SIZE;
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_length = Audio::Timestamp(0, (_stream->size() - START_OF_CDDA_DATA - blocks) / (isStereo() ? 2 : 1), getRate());
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}
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CDDAStream::~CDDAStream() {
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if (_disposeAfterUse == DisposeAfterUse::YES)
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delete _stream;
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}
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bool CDDAStream::seek(const Audio::Timestamp &where) {
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const uint32 seekSample = convertTimeToStreamPos(where, getRate(), isStereo()).totalNumberOfFrames();
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uint32 blocks = seekSample / 1176;
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// Before seeking, read the shift values from the beginning of that block
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_stream->seek(START_OF_CDDA_DATA + blocks * BLOCK_SIZE, SEEK_SET);
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byte shiftVal = _stream->readByte();
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_shiftLeft = shiftVal >> 4;
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_shiftRight = shiftVal & 0x0F;
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_pos = START_OF_CDDA_DATA + blocks + seekSample;
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return _stream->seek(_pos, SEEK_SET);
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}
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int CDDAStream::readBuffer(int16 *buffer, const int numSamples) {
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int samples;
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for (samples = 0 ; samples < numSamples && !_stream->eos() ; ) {
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if (!((_pos - START_OF_CDDA_DATA) % BLOCK_SIZE)) {
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byte shiftVal = _stream->readByte();
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_shiftLeft = shiftVal >> 4;
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_shiftRight = shiftVal & 0x0F;
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_pos++;
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}
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buffer[samples++] = _stream->readSByte() << _shiftLeft;
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buffer[samples++] = _stream->readSByte() << _shiftRight;
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_pos += 2;
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}
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return samples;
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}
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#pragma mark -
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#pragma mark --- CDDA factory functions ---
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#pragma mark -
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Audio::SeekableAudioStream *makeCDDAStream(
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Common::SeekableReadStream *stream,
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DisposeAfterUse::Flag disposeAfterUse) {
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Audio::SeekableAudioStream *s = new CDDAStream(stream, disposeAfterUse);
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if (s && s->endOfData()) {
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delete s;
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return nullptr;
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} else {
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return s;
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}
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return nullptr;
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}
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} // End of namespace Scumm
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