Moved Oki ADPCM aka VOX decoder from SAGA engine to common sound/ directory.

Implemented IMA ADPCM decoder.

svn-id: r17903

3 files changed, 253 insertions, 0 deletions

diff --git a/sound/adpcm.cpp b/sound/adpcm.cpp
new file mode 100644
index 0000000000..18f600ed23
--- /dev/null
+++ b/sound/adpcm.cpp
@@ -0,0 +1,215 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2005 The ScummVM project
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#include "stdafx.h"
+#include "common/stream.h"
+
+#include "sound/audiostream.h"
+#include "sound/adpcm.h"
+
+
+// Routines to convert 12 bit linear samples to the
+// Dialogic or Oki ADPCM coding format aka VOX
+class ADPCMInputStream : public AudioStream {
+private:
+	bool _evenPos;
+	Common::SeekableReadStream *_stream;
+	typesADPCM _type;
+
+	struct adpcmStatus {
+		int16 last;
+		int16 stepIndex;
+	} _status;
+
+	int16 stepAdjust(byte);
+	int16 okiADPCMDecode(byte);
+	int16 imaADPCMDecode(byte);
+
+	int readOkiBuffer(int16 *buffer, const int numSamples);
+	int readIMABuffer(int16 *buffer, const int numSamples);
+
+public:
+	ADPCMInputStream(Common::SeekableReadStream *stream, typesADPCM type);
+	~ADPCMInputStream() {};
+
+	int readBuffer(int16 *buffer, const int numSamples);
+
+	bool endOfData() const { return _stream->eos(); }
+	bool isStereo() const	{ return false; }
+	int getRate() const	{ return 22050; }
+};
+
+
+ADPCMInputStream::ADPCMInputStream(Common::SeekableReadStream *stream, typesADPCM type)
+	: _stream(stream), _evenPos(true), _type(type) {
+
+	_status.last = 0;
+	_status.stepIndex = 0;
+}
+
+int ADPCMInputStream::readBuffer(int16 *buffer, const int numSamples) {
+	switch (_type) {
+	case kADPCMOki:
+		return readOkiBuffer(buffer, numSamples);
+		break;
+	case kADPCMIma:
+		return readIMABuffer(buffer, numSamples);
+		break;
+	default:
+		error("Unsupported ADPCM encoding");
+		break;
+	}
+	return 0;
+}
+
+int ADPCMInputStream::readOkiBuffer(int16 *buffer, const int numSamples) {
+	int samples;
+
+	for (samples = 0; samples < numSamples && !_stream->eos(); samples++) {
+		// * 16 effectively converts 12-bit input to 16-bit output
+		if (_evenPos) {
+			buffer[samples] = okiADPCMDecode((_stream->readByte() >> 4) & 0x0f) * 16;
+			// Rewind back so we will reget byte later
+			_stream->seek(-1, SEEK_CUR);
+		} else {
+			buffer[samples] = okiADPCMDecode(_stream->readByte() & 0x0f) * 16;
+		}
+		_evenPos = !_evenPos;
+	}
+	return samples;
+}
+
+int ADPCMInputStream::readIMABuffer(int16 *buffer, const int numSamples) {
+	int samples;
+
+	for (samples = 0; samples < numSamples && !_stream->eos(); samples++) {
+		if (_evenPos) {
+			buffer[samples] = imaADPCMDecode((_stream->readByte() >> 4) & 0x0f);
+			// Rewind back so we will reget byte later
+			_stream->seek(-1, SEEK_CUR);
+		} else {
+			buffer[samples] = imaADPCMDecode(_stream->readByte() & 0x0f);
+		}
+		_evenPos = !_evenPos;
+	}
+	return samples;
+}
+
+// adjust the step for use on the next sample.
+int16 ADPCMInputStream::stepAdjust(byte code) {
+	static const int16 adjusts[] = {-1, -1, -1, -1, 2, 4, 6, 8};
+
+	return adjusts[code & 0x07];
+}
+
+static const int16 okiStepSize[49] = {
+	  16,   17,   19,   21,   23,   25,   28,   31,
+	  34,   37,   41,   45,   50,   55,   60,   66,
+	  73,   80,   88,   97,  107,  118,  130,  143,
+	 157,  173,  190,  209,  230,  253,  279,  307,
+	 337,  371,  408,  449,  494,  544,  598,  658,
+	 724,  796,  876,  963, 1060, 1166, 1282, 1408,
+	1552
+};
+
+// Decode Linear to ADPCM
+int16 ADPCMInputStream::okiADPCMDecode(byte code) {
+	int16 diff, E, SS, samp;
+
+	SS = okiStepSize[_status.stepIndex];
+	E = SS/8;
+	if (code & 0x01)
+		E += SS/4;
+	if (code & 0x02)
+		E += SS/2;
+	if (code & 0x04)
+		E += SS;
+	diff = (code & 0x08) ? -E : E;
+	samp = _status.last + diff;
+
+    // Clip the values to +/- 2^11 (supposed to be 12 bits)
+	if(samp > 2048)
+		samp = 2048;
+	if(samp < -2048)
+		samp = -2048;
+
+	_status.last = samp;
+	_status.stepIndex += stepAdjust(code);
+	if(_status.stepIndex < 0)
+		_status.stepIndex = 0;
+	if(_status.stepIndex > 48)
+		_status.stepIndex = 48;
+
+	return samp;
+}
+
+AudioStream *makeADPCMStream(Common::SeekableReadStream &stream, typesADPCM type) {
+	AudioStream *audioStream = new ADPCMInputStream(&stream, type);
+
+	return audioStream;
+}
+
+
+static const uint16 imaStepTable[89] = {
+		7,	  8,	9,	 10,   11,	 12,   13,	 14,
+	   16,	 17,   19,	 21,   23,	 25,   28,	 31,
+	   34,	 37,   41,	 45,   50,	 55,   60,	 66,
+	   73,	 80,   88,	 97,  107,	118,  130,	143,
+	  157,	173,  190,	209,  230,	253,  279,	307,
+	  337,	371,  408,	449,  494,	544,  598,	658,
+	  724,	796,  876,	963, 1060, 1166, 1282, 1411,
+	 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024,
+	 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484,
+	 7132, 7845, 8630, 9493,10442,11487,12635,13899,
+	15289,16818,18500,20350,22385,24623,27086,29794,
+	32767
+};
+
+
+int16 ADPCMInputStream::imaADPCMDecode(byte code) {
+	int diff, E, SS, samp;
+
+	SS = imaStepTable[_status.stepIndex];
+
+	E = SS/8;
+	if (code & 0x01)
+		E += SS/4;
+	if (code & 0x02)
+		E += SS/2;
+	if (code & 0x04)
+		E += SS;
+	diff = (code & 0x08) ? -E : E;
+	samp = _status.last + diff;
+
+	if(samp < -0x8000)
+		samp = -0x8000;
+	else if(samp > 0x7fff)
+		samp = 0x7fff;
+
+	_status.last = samp;
+	_status.stepIndex += stepAdjust(code);
+	if(_status.stepIndex < 0)
+		_status.stepIndex = 0;
+	if(_status.stepIndex > 88)
+		_status.stepIndex = 88;
+
+	return samp;
+}
diff --git a/sound/adpcm.h b/sound/adpcm.h
new file mode 100644
index 0000000000..e5c51f36aa
--- /dev/null
+++ b/sound/adpcm.h
@@ -0,0 +1,37 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2005 The ScummVM project
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#ifndef SOUND_ADPCM_H
+#define SOUND_ADPCM_H
+
+#include "stdafx.h"
+#include "common/scummsys.h"
+
+class AudioStream;
+
+enum typesADPCM {
+	kADPCMOki,
+	kADPCMIma
+};
+
+AudioStream *makeADPCMStream(Common::SeekableReadStream &stream, typesADPCM type);
+
+#endif
diff --git a/sound/module.mk b/sound/module.mk
index e57d145b55..5d0297bb11 100644
--- a/sound/module.mk
+++ b/sound/module.mk
@@ -1,6 +1,7 @@
 MODULE := sound
 
 MODULE_OBJS := \
+	sound/adpcm.o \
 	sound/audiocd.o \
 	sound/audiostream.o \
 	sound/flac.o \