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2026-02-02 04:50:13 +01:00

155 lines
4.1 KiB
C++

/* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "engines/stark/formats/iss.h"
#include "audio/decoders/adpcm_intern.h"
#include "audio/decoders/raw.h"
#include "common/substream.h"
namespace Stark {
namespace Formats {
/**
* ADPCM decoder for the .iss files
*/
class ISSADPCMStream : public Audio::Ima_ADPCMStream {
public:
ISSADPCMStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse, uint32 size, int rate, int channels, uint32 blockAlign)
: Ima_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign) {}
protected:
int readBuffer(int16 *buffer, const int numSamples) override {
// Similar to MS IMA, but without the four-bytes-per-channel requirement
int samples;
assert(numSamples % 2 == 0);
for (samples = 0; samples < numSamples && !endOfData(); samples += 2) {
if (_blockPos[0] == _blockAlign) {
// read block header
for (byte i = 0; i < _channels; i++) {
_status.ima_ch[i].last = _stream->readSint16LE();
_status.ima_ch[i].stepIndex = _stream->readSint16LE();
}
_blockPos[0] = 4 * _channels;
}
byte data = _stream->readByte();
buffer[samples + (isStereo() ? 1 : 0)] = decodeIMA(data & 0x0f, isStereo() ? 1 : 0);
buffer[samples + (isStereo() ? 0 : 1)] = decodeIMA((data >> 4) & 0x0f);
_blockPos[0]++;
}
return samples;
}
};
static void skipString(Common::SeekableReadStream *stream) {
// Skip until the next space. Note that this will read past \0
// characters as well. That's not a bug.
byte ch;
while ((ch = stream->readByte()) != 0x20)
;
}
static Common::String readString(Common::SeekableReadStream *stream) {
Common::String ret = "";
byte ch;
while ((ch = stream->readByte()) != 0x20)
ret += ch;
return ret;
}
Audio::RewindableAudioStream *makeISSStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse) {
Common::String codec;
uint16 blockSize, channels, freq = 44100;
uint32 size;
byte flags;
codec = readString(stream);
if (codec.equals("IMA_ADPCM_Sound")) {
codec = readString(stream);
blockSize = (uint16)strtol(codec.c_str(), 0, 10);
skipString(stream);
// name ?
skipString(stream);
// ?
codec = readString(stream);
channels = (uint16)strtol(codec.c_str(), 0, 10) + 1;
skipString(stream);
// ?
codec = readString(stream);
int val = strtol(codec.c_str(), 0, 10);
if (val)
freq /= val;
skipString(stream);
skipString(stream);
codec = readString(stream);
size = (uint32)strtol(codec.c_str(), 0, 10);
return new ISSADPCMStream(stream, DisposeAfterUse::YES, size, freq, channels, blockSize);
} else if (codec.equals("Sound")) {
skipString(stream);
// name ?
codec = readString(stream);
// sample count ?
codec = readString(stream);
channels = (uint16)strtol(codec.c_str(), 0, 10) + 1;
skipString(stream);
// ?
codec = readString(stream);
int val = strtol(codec.c_str(), 0, 10);
if (val)
freq /= val;
skipString(stream);
skipString(stream);
flags = Audio::FLAG_16BITS | Audio::FLAG_LITTLE_ENDIAN;
if (channels == 2)
flags |= Audio::FLAG_STEREO;
return Audio::makeRawStream(new Common::SeekableSubReadStream(stream, stream->pos(), stream->size(), DisposeAfterUse::YES), freq, flags, DisposeAfterUse::YES);
} else {
error("Unknown ISS codec '%s'", codec.c_str());
}
}
} // End of namespace Formats
} // End of namespace Stark