mirror of
https://github.com/libretro/scummvm.git
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126 lines
3.0 KiB
C++
126 lines
3.0 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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#include "sound/vag.h"
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namespace Audio {
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VagStream::VagStream(Common::SeekableReadStream *stream, bool loop, int rate) : _stream(stream) {
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_samplesRemaining = 0;
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_predictor = 0;
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_s1 = _s2 = 0.0;
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_loop = loop;
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_rate = rate;
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}
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VagStream::~VagStream() {
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delete _stream;
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}
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static const double s_vagDataTable[5][2] =
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{
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{ 0.0, 0.0 },
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{ 60.0 / 64.0, 0.0 },
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{ 115.0 / 64.0, -52.0 / 64.0 },
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{ 98.0 / 64.0, -55.0 / 64.0 },
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{ 122.0 / 64.0, -60.0 / 64.0 }
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};
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int VagStream::readBuffer(int16 *buffer, const int numSamples) {
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int32 samplesDecoded = 0;
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if (_samplesRemaining) {
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byte i = 0;
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for (i = 28 - _samplesRemaining; i < 28 && samplesDecoded < numSamples; i++) {
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_samples[i] = _samples[i] + _s1 * s_vagDataTable[_predictor][0] + _s2 * s_vagDataTable[_predictor][1];
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_s2 = _s1;
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_s1 = _samples[i];
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int16 d = (int) (_samples[i] + 0.5);
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buffer[samplesDecoded] = d;
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samplesDecoded++;
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}
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#if 0
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assert(i == 28); // We're screwed if this fails :P
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#endif
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// This might mean the file is corrupted, or that the stream has
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// been closed.
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if (i != 28) return 0;
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_samplesRemaining = 0;
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}
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while (samplesDecoded < numSamples) {
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byte i = 0;
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_predictor = _stream->readByte();
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byte shift = _predictor & 0xf;
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_predictor >>= 4;
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if (_stream->readByte() == 7)
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return samplesDecoded;
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for (i = 0; i < 28; i += 2) {
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byte d = _stream->readByte();
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int16 s = (d & 0xf) << 12;
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if (s & 0x8000)
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s |= 0xffff0000;
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_samples[i] = (double)(s >> shift);
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s = (d & 0xf0) << 8;
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if (s & 0x8000)
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s |= 0xffff0000;
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_samples[i + 1] = (double)(s >> shift);
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}
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for (i = 0; i < 28 && samplesDecoded < numSamples; i++) {
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_samples[i] = _samples[i] + _s1 * s_vagDataTable[_predictor][0] + _s2 * s_vagDataTable[_predictor][1];
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_s2 = _s1;
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_s1 = _samples[i];
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int16 d = (int) (_samples[i] + 0.5);
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buffer[samplesDecoded] = d;
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samplesDecoded++;
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}
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if (i != 27)
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_samplesRemaining = 28 - i;
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}
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if (_loop && _stream->eos())
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rewind();
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return samplesDecoded;
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}
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void VagStream::rewind() {
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_stream->seek(0);
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_samplesRemaining = 0;
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_predictor = 0;
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_s1 = _s2 = 0.0;
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}
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}
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