AUDIO: Add a packetized version of ADPCM streams

audio/decoders/adpcm.cpp

@@ -457,4 +457,34 @@ RewindableAudioStream *makeADPCMStream(Common::SeekableReadStream *stream, Dispo
 	}
 }
 
+class PacketizedADPCMStream : public StatelessPacketizedAudioStream {
+public:
+	PacketizedADPCMStream(ADPCMType type, int rate, int channels, uint32 blockAlign) :
+		StatelessPacketizedAudioStream(rate, channels), _type(type), _blockAlign(blockAlign) {}
+
+protected:
+	AudioStream *makeStream(Common::SeekableReadStream *data);
+
+private:
+	ADPCMType _type;
+	uint32 _blockAlign;
+};
+
+AudioStream *PacketizedADPCMStream::makeStream(Common::SeekableReadStream *data) {
+	return makeADPCMStream(data, DisposeAfterUse::YES, data->size(), _type, getRate(), getChannels(), _blockAlign);
+}
+
+PacketizedAudioStream *makePacketizedADPCMStream(ADPCMType type, int rate, int channels, uint32 blockAlign) {
+	// Filter out types we can't support (they're not fully stateless)
+	switch (type) {
+	case kADPCMOki:
+	case kADPCMDVI:
+		return 0;
+	default:
+		break;
+	}
+
+	return new PacketizedADPCMStream(type, rate, channels, blockAlign);
+}
+
 } // End of namespace Audio

audio/decoders/adpcm.h

@@ -44,6 +44,7 @@ class SeekableReadStream;
 
 namespace Audio {
 
+class PacketizedAudioStream;
 class RewindableAudioStream;
 
 // There are several types of ADPCM encoding, only some are supported here
@@ -81,6 +82,26 @@ RewindableAudioStream *makeADPCMStream(
     int channels,
     uint32 blockAlign = 0);
 
+/**
+ * Creates a PacketizedAudioStream that will automatically queue
+ * packets as individual AudioStreams like returned by makeADPCMStream.
+ *
+ * Due to the ADPCM types not necessarily supporting stateless
+ * streaming, OKI and DVI are not supported by this function
+ * and will return NULL.
+ *
+ * @param type              the compression type used
+ * @param rate              the sampling rate
+ * @param channels          the number of channels
+ * @param blockAlign        block alignment ???
+ * @return The new PacketizedAudioStream or NULL, if the type isn't supported.
+ */
+PacketizedAudioStream *makePacketizedADPCMStream(
+	ADPCMType type,
+	int rate,
+	int channels,
+	uint32 blockAlign = 0);
+
 } // End of namespace Audio
 
 #endif