begin parsing work on AAC info parsing

git-svn-id: https://svn.musicpd.org/mpd/trunk@345 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/tag.c

@@ -173,7 +173,111 @@ MpdTag * mp3TagDup(char * utf8file) {
 #endif
 
 #ifdef HAVE_FAAD
-/* copied from FAAD2 frontend */
+typedef struct {
+	long bytesIntoBuffer;
+	long bytesConsumed;
+	long fileOffset;
+	unsigned char *buffer;
+	int atEof;
+	FILE *infile;
+} AacBuffer;
+
+void fillAacBuffer(AacBuffer *b) {
+	if(b->bytesConsumed > 0) {
+		int bread;
+
+		if(b->bytesIntoBuffer) {
+			memmove((void *)b->buffer,(void*)(b->buffer+
+					b->bytesConsumed),b->bytesIntoBuffer);
+		}
+
+		if(!b->atEof) {
+			bread = fread((void *)(b->buffer+b->bytesIntoBuffer),1,
+					b->bytesConsumed,b->infile);
+			if(bread!=b->bytesConsumed) b->atEof = 1;
+			b->bytesIntoBuffer+=bread;
+		}
+
+		b->bytesConsumed = 0;
+
+		if(b->bytesIntoBuffer > 3) {
+			if(memcmp(b->buffer,"TAG",3)==0) b->bytesIntoBuffer = 0;
+		}
+		if(b->bytesIntoBuffer > 11) {
+			if(memcmp(b->buffer,"LYRICSBEGIN",11)==0) {
+				b->bytesIntoBuffer = 0;
+			}
+		}
+		if(b->bytesIntoBuffer > 8) {
+			if(memcmp(b->buffer,"APETAGEX",8)==0) {
+				b->bytesIntoBuffer = 0;
+			}
+		}
+	}
+}
+
+void advanceAacBuffer(AacBuffer * b, int bytes) {
+	b->fileOffset+=bytes;
+	b->bytesConsumed = bytes;
+	b->bytesIntoBuffer-=bytes;
+}
+
+static int adtsSampleRates[] = {96000,88200,64000,48000,44100,32000,24000,22050,
+				16000,12000,11025,8000,7350,0,0,0};
+
+int adtsParse(AacBuffer * b, float * length) {
+	int frames, frameLength;
+	int tFrameLength = 0;
+	int sampleRate = 0;
+	float framesPerSec, bytesPerFrame;
+
+	/* Read all frames to ensure correct time and bitrate */
+	for(frames = 0; ;frames++) {
+		fillAacBuffer(b);
+
+		if(b->bytesIntoBuffer > 7) {
+			/* check syncword */
+			if (!((b->buffer[0] == 0xFF) && 
+				((b->buffer[1] & 0xF6) == 0xF0)))
+			{
+				break;
+			}
+
+			if(frames==0) {
+				sampleRate = adtsSampleRates[
+						(b->buffer[2]&0x3c)>>2];
+			}
+
+			frameLength =  ((((unsigned int)b->buffer[3] & 0x3)) 
+					<< 11) | (((unsigned int)b->buffer[4])  
+                			<< 3) | (b->buffer[5] >> 5);
+
+			tFrameLength+=frameLength;
+
+			if(frameLength > b->bytesIntoBuffer) break;
+
+			advanceAacBuffer(b,frameLength);
+		}
+		else break;
+	}
+
+	framesPerSec = (float)sampleRate/1024.0;
+	if(frames!=0) {
+		bytesPerFrame = (float)tFrameLength/(float)(frames*1000);
+	}
+	else bytesPerFrame = 0;
+	if(framesPerSec!=0) *length = (float)frames/framesPerSec;
+	else *length = 1;
+
+	return 1;
+}
+
+MpdTag * aacTagDup(char * utf8file) {
+	MpdTag * ret = NULL;
+
+	return ret;
+}
+
 MpdTag * mp4DataDup(char * utf8file, int * mp4MetadataFound) {
 	MpdTag * ret = NULL;
 	FILE * fh;