Initial commit

engines/bladerunner/aud_stream.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 "bladerunner/aud_stream.h"
+
+#include "bladerunner/audio_cache.h"
+
+#include "common/util.h"
+
+namespace BladeRunner {
+
+AudStream::AudStream(byte *data, int overrideFrequency) {
+	_hash  = 0;
+	_cache = nullptr;
+	_overrideFrequency = overrideFrequency;
+
+	init(data);
+}
+
+AudStream::AudStream(AudioCache *cache, int32 hash, int overrideFrequency) {
+	assert(cache != nullptr);
+
+	_cache = cache;
+	_hash  = hash;
+	_overrideFrequency = overrideFrequency;
+
+	_cache->incRef(_hash);
+
+	init(_cache->findByHash(_hash));
+}
+
+void AudStream::init(byte *data) {
+	_data = data;
+	_frequency = READ_LE_UINT16(_data);
+	_size = READ_LE_UINT32(_data + 2);
+	_sizeDecompressed = READ_LE_UINT32(_data + 6);
+	_flags = *(_data + 10);
+	_compressionType = *(_data + 11);
+
+	_end = _data + _size + 12;
+	assert(_end - _data >= 12);
+
+	_deafBlockRemain = 0;
+	_p = _data + 12;
+}
+
+AudStream::~AudStream() {
+	if (_cache) {
+		_cache->decRef(_hash);
+	}
+}
+
+int AudStream::readBuffer(int16 *buffer, const int numSamples) {
+	int samplesRead = 0;
+
+	if (_compressionType == 99) {
+		assert(numSamples % 2 == 0);
+
+		while (samplesRead < numSamples) {
+			if (_deafBlockRemain == 0) {
+				if (_end - _p == 0)
+					break;
+
+				assert(_end - _p >= 6);
+
+				uint16 blockSize     = READ_LE_UINT16(_p);
+				uint16 blockOutSize  = READ_LE_UINT16(_p + 2);
+				uint32 sig           = READ_LE_UINT32(_p + 4);
+				_p += 8;
+
+				assert(sig == 0xdeaf);
+				assert(_end - _p >= blockSize);
+
+				// TODO: Previously we asserted that
+				// blockOutSize == 4 * blockSize, but
+				// occasionally, at the end of an AUD,
+				// we see blockOutSize == 4 * blockSize + 2
+				// Investigate how BLADE.EXE handles this.
+
+				assert(blockOutSize / 4 == blockSize);
+
+				_deafBlockRemain = blockSize;
+			}
+
+			assert(_end - _p >= _deafBlockRemain);
+
+			int bytesConsumed = MIN<int>(_deafBlockRemain, (numSamples - samplesRead) / 2);
+			if (buffer) {
+				_decoder.decode(_p, bytesConsumed, buffer + samplesRead, false);
+			} else {
+				_decoder.decode(_p, bytesConsumed, nullptr, false);
+			}
+			_p += bytesConsumed;
+			_deafBlockRemain -= bytesConsumed;
+
+			samplesRead += 2 * bytesConsumed;
+		}
+	} else {
+		samplesRead = MIN(numSamples, (int)(_end - _p) / 2);
+		if (buffer) {
+			for (int i = 0; i < samplesRead; ++i, _p += 2) {
+				buffer[i] = READ_LE_UINT16(_p);
+			}
+		}
+	}
+
+	return samplesRead;
+}
+
+int AudStream::getBytesPerSecond() const {
+	int bytesPerSecond = _overrideFrequency > 0 ? _overrideFrequency : _frequency;
+	if (_flags & 1) { // 16 bit
+		bytesPerSecond *= 2;
+	}
+	if (_flags & 2) { // stereo
+		bytesPerSecond *= 2;
+	}
+	return bytesPerSecond;
+}
+
+bool AudStream::startAtSecond(uint32 startSecond) {
+	uint32 audStreamLengthMillis = getLength();
+	if (startSecond == 0 || startSecond * 1000 > audStreamLengthMillis || audStreamLengthMillis == 0) { 
+		return false;
+	}
+	if (rewind()) {
+		int samplesPerSecond = _overrideFrequency > 0 ? _overrideFrequency : _frequency;
+		readBuffer(nullptr, startSecond * samplesPerSecond);
+		return true;
+	}
+	return false;
+}
+
+bool AudStream::rewind() {
+	_p = _data + 12;
+	_decoder.setParameters(0, 0);
+	return true;
+}
+
+/**
+* Returns audio length in milliseconds
+*/
+uint32 AudStream::getLength() const {
+	// since everything is 44100, we easily get overflows with ints
+	// thus we must use doubles
+	int bytesPerSecond = getBytesPerSecond();
+	if (bytesPerSecond <= 0) {
+		return 0u;
+	}
+	double res = (double)_sizeDecompressed * 1000.0 / (double)bytesPerSecond;
+	return (uint32)res;
+}
+
+} // End of namespace BladeRunner