Attempt to add rewinding to CoreAudio for streamed source files, but it doesn't work, it still fails to play anything from a stream

Plugins/CoreAudio/CoreAudioDecoder.h

@@ -32,6 +32,9 @@
     AudioFileID             _audioFile;
 	ExtAudioFileRef			_in;
     
+    long                    rewindStart;
+    NSMutableData         * rewindBuffer;
+
 	int bitrate;
 	int bitsPerSample;
     BOOL floatingPoint;

Plugins/CoreAudio/CoreAudioDecoder.m

@@ -24,6 +24,8 @@
 
 #import "Logging.h"
 
+#define REWIND_SIZE 131072
+
 @interface CoreAudioDecoder (Private)
 - (BOOL) readInfoFromExtAudioFileRef;
 @end
@@ -42,16 +44,49 @@ static OSStatus readProc(void* clientData,
     if (position != pSelf->_lastPosition) {
         if ([source seekable])
             [source seek:position whence:SEEK_SET];
-        else
+        else if (position < pSelf->rewindStart)
             return seekErr;
     }
 
-    size_t bytesRead = [source read:buffer amount:requestCount];
+    size_t copyMax = 0;
+    size_t bytesRead = 0;
+    size_t rewindBytes = 0;
+
+    if (![source seekable]) {
+        long rewindStart = pSelf->rewindStart;
+        rewindBytes = [pSelf->rewindBuffer length];
+
+        if ( position < rewindStart + rewindBytes ) {
+            const uint8_t * rewindBuffer = (const uint8_t *)([pSelf->rewindBuffer bytes]);
+            copyMax = rewindStart + rewindBytes - position;
+            if (copyMax > requestCount)
+                copyMax = requestCount;
+            memcpy(buffer, rewindBuffer + (position - rewindStart), copyMax);
+            requestCount -= copyMax;
+            position += copyMax;
+        }
+    }
+    
+    if ( requestCount )
+        bytesRead = [source read:(((uint8_t *)buffer) + copyMax) amount:requestCount];
+    
+    if (![source seekable]) {
+        size_t copyBytes = bytesRead;
+        if (copyBytes) {
+            ssize_t removeBytes = ((rewindBytes + copyBytes) - REWIND_SIZE);
+            if (removeBytes > 0) {
+                NSRange range = NSMakeRange(0, removeBytes);
+                [pSelf->rewindBuffer replaceBytesInRange:range withBytes:NULL length:0];
+                pSelf->rewindStart += removeBytes;
+            }
+            [pSelf->rewindBuffer appendBytes:buffer length:copyBytes];
+        }
+    }
     
     pSelf->_lastPosition = position + bytesRead;
 
     if(actualCount)
-        *actualCount = (UInt32) bytesRead;
+        *actualCount = (UInt32) (copyMax + bytesRead);
 
     return noErr;
 }
@@ -107,6 +142,9 @@ static SInt64 getSizeProc(void* clientData) {
     _audioSource = source;
     _lastPosition = [source tell];
     
+    rewindStart = _lastPosition;
+    rewindBuffer = [[NSMutableData alloc] init];
+
     err = AudioFileOpenWithCallbacks((__bridge void *)self, readProc, 0, getSizeProc, 0, 0, &_audioFile);
     if(noErr != err) {
         ALog(@"Error opening callback interface to file: %d", err);
@@ -244,9 +282,19 @@ static SInt64 getSizeProc(void* clientData) {
 
 + (NSArray *)mimeTypes
 {
+    OSStatus           err;
+    UInt32             size;
+    NSArray *sAudioMIMETypes;
+    
+    size    = sizeof(sAudioMIMETypes);
+    err     = AudioFileGetGlobalInfo(kAudioFileGlobalInfo_AllMIMETypes, 0, NULL, &size, &sAudioMIMETypes);
+    if(noErr != err) {
         return nil;
     }
     
+	return sAudioMIMETypes;
+}
+
 + (float)priority
 {
     return 1.0;