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author | Max Horn | 2011-02-09 01:09:01 +0000 |
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committer | Max Horn | 2011-02-09 01:09:01 +0000 |
commit | 42ab839dd6c8a1570b232101eb97f4e54de57935 (patch) | |
tree | 3b763d8913a87482b793e0348c88b9a5f40eecc9 /audio/decoders/vag.cpp | |
parent | 386203a3d6ce1abf457c9110d695408ec5f01b85 (diff) | |
download | scummvm-rg350-42ab839dd6c8a1570b232101eb97f4e54de57935.tar.gz scummvm-rg350-42ab839dd6c8a1570b232101eb97f4e54de57935.tar.bz2 scummvm-rg350-42ab839dd6c8a1570b232101eb97f4e54de57935.zip |
AUDIO: Rename sound/ dir to audio/
svn-id: r55850
Diffstat (limited to 'audio/decoders/vag.cpp')
-rw-r--r-- | audio/decoders/vag.cpp | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/audio/decoders/vag.cpp b/audio/decoders/vag.cpp new file mode 100644 index 0000000000..2c3a36202a --- /dev/null +++ b/audio/decoders/vag.cpp @@ -0,0 +1,150 @@ +/* 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. + * + * $URL$ + * $Id$ + * + */ + +#include "audio/decoders/vag.h" +#include "audio/audiostream.h" +#include "common/stream.h" + +namespace Audio { + +class VagStream : public Audio::RewindableAudioStream { +public: + VagStream(Common::SeekableReadStream *stream, int rate); + ~VagStream(); + + bool isStereo() const { return false; } + bool endOfData() const { return _stream->pos() == _stream->size(); } + int getRate() const { return _rate; } + int readBuffer(int16 *buffer, const int numSamples); + + bool rewind(); +private: + Common::SeekableReadStream *_stream; + + byte _predictor; + double _samples[28]; + byte _samplesRemaining; + int _rate; + double _s1, _s2; +}; + +VagStream::VagStream(Common::SeekableReadStream *stream, int rate) : _stream(stream) { + _samplesRemaining = 0; + _predictor = 0; + _s1 = _s2 = 0.0; + _rate = rate; +} + + +VagStream::~VagStream() { + delete _stream; +} + +static const double s_vagDataTable[5][2] = + { + { 0.0, 0.0 }, + { 60.0 / 64.0, 0.0 }, + { 115.0 / 64.0, -52.0 / 64.0 }, + { 98.0 / 64.0, -55.0 / 64.0 }, + { 122.0 / 64.0, -60.0 / 64.0 } + }; + +int VagStream::readBuffer(int16 *buffer, const int numSamples) { + int32 samplesDecoded = 0; + + if (_samplesRemaining) { + byte i = 0; + + for (i = 28 - _samplesRemaining; i < 28 && samplesDecoded < numSamples; i++) { + _samples[i] = _samples[i] + _s1 * s_vagDataTable[_predictor][0] + _s2 * s_vagDataTable[_predictor][1]; + _s2 = _s1; + _s1 = _samples[i]; + int16 d = (int) (_samples[i] + 0.5); + buffer[samplesDecoded] = d; + samplesDecoded++; + } + +#if 0 + assert(i == 28); // We're screwed if this fails :P +#endif + // This might mean the file is corrupted, or that the stream has + // been closed. + if (i != 28) return 0; + + _samplesRemaining = 0; + } + + while (samplesDecoded < numSamples) { + byte i = 0; + + _predictor = _stream->readByte(); + byte shift = _predictor & 0xf; + _predictor >>= 4; + + if (_stream->readByte() == 7) + return samplesDecoded; + + for (i = 0; i < 28; i += 2) { + byte d = _stream->readByte(); + int16 s = (d & 0xf) << 12; + if (s & 0x8000) + s |= 0xffff0000; + _samples[i] = (double)(s >> shift); + s = (d & 0xf0) << 8; + if (s & 0x8000) + s |= 0xffff0000; + _samples[i + 1] = (double)(s >> shift); + } + + for (i = 0; i < 28 && samplesDecoded < numSamples; i++) { + _samples[i] = _samples[i] + _s1 * s_vagDataTable[_predictor][0] + _s2 * s_vagDataTable[_predictor][1]; + _s2 = _s1; + _s1 = _samples[i]; + int16 d = (int) (_samples[i] + 0.5); + buffer[samplesDecoded] = d; + samplesDecoded++; + } + + if (i != 27) + _samplesRemaining = 28 - i; + } + + return samplesDecoded; +} + +bool VagStream::rewind() { + _stream->seek(0); + _samplesRemaining = 0; + _predictor = 0; + _s1 = _s2 = 0.0; + + return true; +} + +RewindableAudioStream *makeVagStream(Common::SeekableReadStream *stream, int rate) { + return new VagStream(stream, rate); +} + +} |