Merge support of apple's ALAC decoder

apple_alac.cpp

@@ -0,0 +1,58 @@
+#include <string.h>
+
+// these are headers for the ALAC decoder, utilities and endian utilities
+#include <alac/ALACDecoder.h>
+#include <alac/ALACBitUtilities.h>
+#include <alac/EndianPortable.h>
+
+#include "config.h"
+#include "apple_alac.h"
+
+typedef struct magicCookie {
+  ALACSpecificConfig config;
+  ALACAudioChannelLayout channelLayoutInfo; // seems to be unused
+} magicCookie;
+
+magicCookie cookie;
+ALACDecoder * theDecoder;
+
+extern "C" int apple_alac_init(int frame_size,int sample_size,int sample_rate) {
+
+  memset(&cookie,0,sizeof(magicCookie));
+  
+  #define CHANNELS_PER_FRAME  2
+
+  //create a magic cookie for the decoder
+  
+  cookie.config.frameLength = Swap32NtoB(frame_size);
+  cookie.config.compatibleVersion = 0;
+  cookie.config.bitDepth = sample_size;
+  cookie.config.pb = 40;
+  cookie.config.mb = 10;
+  cookie.config.kb = 14;
+  cookie.config.numChannels = CHANNELS_PER_FRAME;
+  cookie.config.maxRun = Swap16NtoB(255);
+  cookie.config.maxFrameBytes = 0;
+  cookie.config.avgBitRate = 0;
+  cookie.config.sampleRate = Swap32NtoB(sample_rate);
+  
+  theDecoder = new ALACDecoder;
+  theDecoder->Init(&cookie, sizeof(magicCookie));  
+
+  return 0;
+}
+
+extern "C" int apple_alac_decode_frame(unsigned char *sampleBuffer, uint32_t bufferLength, unsigned char *dest, int *outsize)
+{
+  uint32_t numFrames = 0;
+  BitBuffer theInputBuffer;
+  BitBufferInit(&theInputBuffer, sampleBuffer, bufferLength);
+  theDecoder->Decode(&theInputBuffer, dest, Swap32BtoN(cookie.config.frameLength), CHANNELS_PER_FRAME, &numFrames);
+  *outsize = numFrames;
+  return 0;
+}
+
+extern "C" int apple_alac_terminate() {
+  delete(theDecoder);
+}
+