[Scummvm-cvs-logs] SF.net SVN: scummvm:[35209] scummvm/trunk/sound/adpcm.cpp

[drmccoy at users.sourceforge.net]

Revision: 35209
          http://scummvm.svn.sourceforge.net/scummvm/?rev=35209&view=rev
Author:   drmccoy
Date:     2008-12-02 21:58:48 +0000 (Tue, 02 Dec 2008)

Log Message:
-----------
Apparently, constraining the number of mixing samples to be divisible by 4 is too strict, so I'm changing readBufferTinsel6() around a bit to allow for any number of samples (at the cost of adding 2 variables and a bit complexity ;))

Modified Paths:
--------------
    scummvm/trunk/sound/adpcm.cpp

Modified: scummvm/trunk/sound/adpcm.cpp
===================================================================
--- scummvm/trunk/sound/adpcm.cpp	2008-12-02 21:26:41 UTC (rev 35208)
+++ scummvm/trunk/sound/adpcm.cpp	2008-12-02 21:58:48 UTC (rev 35209)
@@ -43,6 +43,8 @@
 	typesADPCM _type;
 	uint32 _blockAlign;
 	uint32 _blockPos;
+	uint8 _chunkPos;
+	uint16 _chunkData;
 	int _blockLen;
 	int _rate;
 
@@ -111,6 +113,8 @@
 	_endpos = stream->pos() + size;
 	_blockLen = 0;
 	_blockPos = _blockAlign; // To make sure first header is read
+	_chunkPos = 0;
+	_chunkData = 0;
 
 	if (type == kADPCMMSIma && blockAlign == 0)
 		error("ADPCMInputStream(): blockAlign isn't specifiled for MS IMA ADPCM");
@@ -332,30 +336,43 @@
 
 int ADPCMInputStream::readBufferTinsel6(int channels, int16 *buffer, const int numSamples) {
 	int samples;
-	uint16 data;
 	const double eVal = 1.032226562;
 
 	samples = 0;
 
-	assert(numSamples % 4 == 0);
-
 	while (samples < numSamples && !_stream->eos() && _stream->pos() < _endpos) {
 		if (_blockPos == _blockAlign) {
 			readBufferTinselHeader();
 			_blockPos = 0;
+			_chunkPos = 0;
 		}
 
-		for (; samples < numSamples && _blockPos < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 4, _blockPos += 3) {
-			// Read 3 bytes = 24 bits = four 6 bit blocks
-			data = _stream->readByte();
-			buffer[samples] = TO_LE_16(decodeTinsel((data << 8) & 0xFC00, eVal));
-			data = (data << 8) | (_stream->readByte());
-			buffer[samples+1] = TO_LE_16(decodeTinsel((data << 6) & 0xFC00, eVal));
-			data = (data << 8) | (_stream->readByte());
-			buffer[samples+2] = TO_LE_16(decodeTinsel((data << 4) & 0xFC00, eVal));
-			data = (data << 8);
-			buffer[samples+3] = TO_LE_16(decodeTinsel((data << 2) & 0xFC00, eVal));
+		for (; samples < numSamples && _blockPos < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples++, _chunkPos = (_chunkPos + 1) % 4) {
+
+			switch (_chunkPos) {
+			case 0:
+				_chunkData = _stream->readByte();
+				buffer[samples] = TO_LE_16(decodeTinsel((_chunkData << 8) & 0xFC00, eVal));
+				break;
+			case 1:
+				_chunkData = (_chunkData << 8) | (_stream->readByte());
+				buffer[samples] = TO_LE_16(decodeTinsel((_chunkData << 6) & 0xFC00, eVal));
+				_blockPos++;
+				break;
+			case 2:
+				_chunkData = (_chunkData << 8) | (_stream->readByte());
+				buffer[samples] = TO_LE_16(decodeTinsel((_chunkData << 4) & 0xFC00, eVal));
+				_blockPos++;
+				break;
+			case 3:
+				_chunkData = (_chunkData << 8);
+				buffer[samples] = TO_LE_16(decodeTinsel((_chunkData << 2) & 0xFC00, eVal));
+				_blockPos++;
+				break;
+			}
+			
 		}
+
 	}
 
 	return samples;


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