APE reader: optimize seeking

* The APE SDK can only decode rather big chunks at a time (several
seconds), so our reader keeps an internal buffer of the last decoded
chunk.
* However, this was always dropped when seeking, meaning the same few
seconds of sound were decoded again and again.
* I'm not sure why MediaPlayer is trying to seek to the position it
already is at, but we can make it work, so why not.

Now the existing buffer is reused if possible when seeking. This makes
it possible to play APE files in MediaPlayer.

Also, several more style fixes.

src/add-ons/media/plugins/ape_reader/APEReader.cpp

@@ -83,18 +83,20 @@ TAPEReader::GetNextChunk(void* oCookie, const void** oChunkBuffer,
 	// check whether song is finished or not
 	if (mReadPosTotal - mReadPos + mPlayPos >= mDataSize)
 		return B_ERROR;
+
 	// reading data
-	if ( mPlayPos >= mReadPos ) {
+	if (mPlayPos >= mReadPos )
 		ReadBlocks();
-	}
+
 	// passing data
-	if ( mReadPos-mPlayPos >= BUFFER_SIZE ) {
+	if (mReadPos-mPlayPos >= BUFFER_SIZE)
 		aOutSize = BUFFER_SIZE;
-	} else {
+	else
 		aOutSize = mReadPos-mPlayPos;
-	}
+
 	*oChunkBuffer = &mDecodedData[mPlayPos];
 	mPlayPos += aOutSize;
+
 	// passing info
 	*oChunkSize = aOutSize;
 	oMediaHeader->start_time = CurrentTime();
@@ -110,6 +112,7 @@ TAPEReader::GetStreamInfo(void* oCookie, int64* oFrameCount,
 {
 	if (LoadAPECheck() != B_OK)
 		return LoadAPECheck();
+
 	*oFrameCount = mDataSize / (mDecomp->GetInfo(APE_INFO_BITS_PER_SAMPLE) / 8
 			* mDecomp->GetInfo(APE_INFO_CHANNELS));
 	*oDuration = mDecomp->GetInfo(APE_INFO_LENGTH_MS)
@@ -118,11 +121,11 @@ TAPEReader::GetStreamInfo(void* oCookie, int64* oFrameCount,
 	oFormat->type = B_MEDIA_RAW_AUDIO;
 	oFormat->u.raw_audio.frame_rate = mDecomp->GetInfo(APE_INFO_SAMPLE_RATE);
 	oFormat->u.raw_audio.channel_count = mDecomp->GetInfo(APE_INFO_CHANNELS);
-	if ( mDecomp->GetInfo(APE_INFO_BITS_PER_SAMPLE) == 16 ) {
+	if ( mDecomp->GetInfo(APE_INFO_BITS_PER_SAMPLE) == 16 )
 		oFormat->u.raw_audio.format = media_raw_audio_format::B_AUDIO_SHORT;
-	} else {
+	else
 		oFormat->u.raw_audio.format = media_raw_audio_format::B_AUDIO_UCHAR;
-	}
+
 	oFormat->u.raw_audio.byte_order = B_MEDIA_LITTLE_ENDIAN;
 	oFormat->u.raw_audio.buffer_size = BUFFER_SIZE;
 	oInfoBuffer = NULL;
@@ -190,9 +193,16 @@ TAPEReader::Seek(void *cookie, uint32 flags, int64 *frame, bigtime_t *time)
 	} else
 		return B_ERROR;
 
+	int64 aNewTime = aNewBlock * mDecomp->GetInfo(APE_INFO_BLOCK_ALIGN);
+	if (mReadPosTotal - mReadPos < aNewTime && mReadPosTotal > aNewTime) {
+		// Requested seek frame is already in the current buffer, no need to
+		// actually seek, just set the play position
+		mPlayPos = aNewTime - mReadPosTotal + mReadPos;
+	} else {
 		mReadPosTotal = aNewBlock * mDecomp->GetInfo(APE_INFO_BLOCK_ALIGN);
 		mDecomp->Seek(aNewBlock);
 		ReadBlocks();
+	}
 	return B_OK;
 }
 
@@ -205,10 +215,12 @@ TAPEReader::Sniff(int32* oStreamCount)
 	mSrcPIO = dynamic_cast<BPositionIO*>(Source());
 	if (mSrcPIO == NULL)
 		return B_ERROR;
+
 	mPositionBridgeIO.SetPositionIO(mSrcPIO);
 	mDecomp = CreateIAPEDecompressEx(&mPositionBridgeIO);
 	if (mDecomp == NULL)
 		return B_ERROR;
+
 	// prepare about data
 	mDataSize = static_cast<int64>(mDecomp->GetInfo(APE_DECOMPRESS_TOTAL_BLOCKS))
 			*mDecomp->GetInfo(APE_INFO_BLOCK_ALIGN);

src/add-ons/media/plugins/ape_reader/APEReader.h

@@ -1,18 +1,19 @@
 #ifndef	___APEReader_H_
 #define	___APEReader_H_
-//------------------------------------------------------------------------------
+
-// BeOS
+
-// MAC
 #include "MACLib.h"
 #include "MonkeysAudioMIMEType.h"
 #include "PositionBridgeIO.h"
-// Proj
+
 #include "ReaderPlugin.h"		// Haiku private header
-//------------------------------------------------------------------------------
+
+
 const int32		BLOCK_COUNT = 1024*4;	// number of blocks, get from MACLib at once
 const int32		BUFFER_SIZE = 1024*4;	// size of audio data passing to Media Kit
 const int32		MEDIA_FILE_FORMAT_VERSION = 100;	// media_file_format::version
-//==============================================================================
+
+
 class	TAPEReader : public Reader
 {
 public:
@@ -28,7 +29,8 @@ public:
 	virtual	status_t	AllocateCookie(int32 oStreamNumber, void** oCookie);
 	virtual	status_t	FreeCookie(void* oCookie);
 
-	virtual	status_t	GetStreamInfo(void* oCookie, int64* oFrameCount, bigtime_t* oDuration, media_format* oFormat,
+	virtual	status_t	GetStreamInfo(void* oCookie, int64* oFrameCount,
+							bigtime_t* oDuration, media_format* oFormat,
 							const void** oInfoBuffer, size_t* oInfoSize);
 
 	virtual	status_t		Seek(void *cookie, uint32 flags,
@@ -37,7 +39,8 @@ public:
 	virtual	status_t		FindKeyFrame(void* cookie, uint32 flags,
 								int64* frame, bigtime_t* time);
 
-	virtual	status_t	GetNextChunk(void* oCookie, const void** oChunkBuffer, size_t* oChunkSize, media_header* oMediaHeader);
+	virtual	status_t	GetNextChunk(void* oCookie, const void** oChunkBuffer,
+								size_t* oChunkSize, media_header* oMediaHeader);
 
 private:
 	typedef	Reader	SUPER;
@@ -57,7 +60,8 @@ private:
 	IAPEDecompress*		mDecomp;
 	TPositionBridgeIO	mPositionBridgeIO;
 };
-//==============================================================================
+
+
 class	TAPEReaderPlugin : public ReaderPlugin
 {
 public:
@@ -66,7 +70,9 @@ public:
 
 	virtual	Reader*	NewReader();
 };
-//==============================================================================
+
+
 MediaPlugin*	instantiate_plugin();
-//==============================================================================
+
+
 #endif	// ___APEReader_H_