Initial commit

engines/stark/formats/iss.cpp

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+/* 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