RageSoundReader::Read() returns sound data which may be at a

different rate than the source it's reading from; one second
of returned data may correspond to two seconds in the source
material.

GetStreamToSourceRatio returns the ratio of returned data in
the next Read() call to source data.  This is propagated
upwards in the filter tree, so rate changes by a speed changer
in the middle of the tree will be reflected in the final
GetStreamToSourceRatio().

This means that whenever the ratio changes, Read() stops
returning data; it returns whatever it has, so the caller
has an opportunity to call GetStreamToSourceRatio again
and notice the change.

These semantics can be annoying to implement in some
cases, where only the processing of Read() may notice
a ratio change.  Read() may want to return 0, to say
"something changed, call GetStreamToSourceRatio again",
but 0 means EOF.

Add RageSoundReader::END_OF_FILE.  0 is now no
longer a special case; it means "there's more data, I
just didn't return any this time".  This is functionally
equivalent to errno EINTR.

stepmania/src/RageSound.cpp

@@ -288,18 +288,29 @@ int RageSound::GetData( char *pBuffer, int iFrames )
 
 		fRate = m_pSource->GetStreamToSourceRatio();
 		int iNewSourceFrame = m_pSource->GetNextSourceFrame();
-		iGotFrames = m_pSource->Read( pBuffer, iFrames );
-		if( iGotFrames == -1 )
+		while( iGotFrames == 0 )
 		{
-			Fail( m_pSource->GetError() );
+			iGotFrames = m_pSource->Read( pBuffer, iFrames );
+			if( iGotFrames == RageSoundReader::ERROR )
+			{
+				Fail( m_pSource->GetError() );
 
-			/* Pretend we got EOF. */
-			return 0;
+				/* Pretend we got EOF. */
+				return 0;
+			}
+
+			if( iGotFrames == RageSoundReader::END_OF_FILE )
+			{
+				iGotFrames = 0;
+				break;
+			}
+
+			ASSERT_M( iGotFrames >= 0, ssprintf("%i", iGotFrames) ); // unhandled error condition
 		}
 
 		/* If we didn't get any data, don't update iSourceFrame, so we just keep
 		 * extrapolating if we're in M_CONTINUE. */
-		if( iGotFrames != 0 )
+		if( iGotFrames == 0 )
 			iSourceFrame = iNewSourceFrame;
 
 		if( m_pSource->GetNumChannels() == 1 )

stepmania/src/RageSoundReader.h

@@ -18,6 +18,12 @@ public:
 	virtual bool IsStreamingFromDisk() const = 0;
 	virtual bool SetProperty( const RString &sProperty, float fValue ) { return false; }
 
+	/* Return values for Read(). */
+	enum {
+		ERROR = -1,
+		END_OF_FILE = -2
+	};
+
 	/* GetNextSourceFrame() provides the source frame associated with the next frame
 	 * that will be read via Read().  GetStreamToSourceRatio() returns the ratio
 	 * for extrapolating the source frames of the remainder of the block.  These

stepmania/src/RageSoundReader_ChannelSplit.cpp

@@ -48,7 +48,7 @@ public:
 	}
 
 	/* Request that m_sBuffer contain frames [iStartFrame,iStartFrame+iFrames). */
-	bool ReadBuffer();
+	int ReadBuffer();
 	int m_iRefCount;
 
 	RageSoundReader *m_pSource;
@@ -111,10 +111,11 @@ bool RageSoundReader_Split::SetProperty( const RString &sProperty, float fValue
 int RageSoundReader_Split::Read( char *pBuf, int iFrames )
 {
 	m_iRequestFrames = iFrames;
-	if( !m_pImpl->ReadBuffer() )
+	int iRet = m_pImpl->ReadBuffer();
+	if( iRet < 0 )
 	{
 		this->SetError( m_pImpl->m_pSource->GetError() );
-		return -1;
+		return iRet;
 	}
 
 	int iBytesAvailable = m_pImpl->m_sBuffer.size();
@@ -153,7 +154,7 @@ int RageSoundReader_Split::Read( char *pBuf, int iFrames )
 	return iFramesAvailable;
 }
 
-bool RageSoundSplitterImpl::ReadBuffer()
+int RageSoundSplitterImpl::ReadBuffer()
 {
 	/* Discard any bytes that are no longer requested by any sound. */
 	int iMinFrameRequested = INT_MAX;
@@ -182,21 +183,21 @@ bool RageSoundSplitterImpl::ReadBuffer()
 
 	int iFramesToRead = iMaxFrameRequested - (m_iBufferPositionFrames + iFramesBuffered);
 	if( iFramesToRead <= 0 )
-		return true; // requested data already buffered
+		return 1; // requested data already buffered
 
 	int iBytesToRead = iFramesToRead * sizeof(int16_t) * m_pSource->GetNumChannels();
 	int iOldSizeBytes = m_sBuffer.size();
 	m_sBuffer.resize( iOldSizeBytes + iBytesToRead );
 	int iGotFrames = m_pSource->Read( &m_sBuffer[0] + iOldSizeBytes, iFramesToRead );
-	if( iGotFrames == -1 )
+	if( iGotFrames < 0 )
 	{
 		m_sBuffer.resize( iOldSizeBytes );
-		return false;
+		return iGotFrames;
 	}
 
 	int iGotBytes = iGotFrames * sizeof(int16_t) * m_pSource->GetNumChannels();
 	m_sBuffer.resize( iOldSizeBytes + iGotBytes );
-	return true;
+	return 1;
 }
 
 void RageSoundReader_Split::AddSourceChannelToSound( int iFromChannel, int iToChannel )

stepmania/src/RageSoundReader_MP3.cpp

@@ -765,9 +765,9 @@ int RageSoundReader_MP3::Read( char *buf, int iFrames )
 		/* Decode more from the MP3 stream. */
 		int ret = do_mad_frame_decode();
 		if( ret == 0 )
-			return iFramesWritten;
+			return END_OF_FILE;
 		if( ret == -1 )
-			return -1;
+			return ERROR;
 
 		synth_output();
 	}

stepmania/src/RageSoundReader_Pan.cpp

@@ -17,6 +17,12 @@ int RageSoundReader_Pan::Read( char *pBuf, int iFrames )
 		iFrames /= 2;
 
 	iFrames = m_pSource->Read( pBuf, iFrames );
+	if( iFrames < 0 )
+	{
+		this->SetError( m_pSource->GetError() );
+		return iFrames;
+	}
+
 	int iSamples = iFrames * m_pSource->GetNumChannels();
 	
 	int16_t *pSampleBuf = (int16_t *) pBuf;

stepmania/src/RageSoundReader_Preload.cpp

@@ -126,6 +126,8 @@ int RageSoundReader_Preload::Read( char *pBuffer, int iFrames )
 	const int iFramesAvail = iSizeFrames - m_iPosition;
 
 	iFrames = min( iFrames, iFramesAvail );
+	if( iFrames == 0 )
+		return END_OF_FILE;
 	memcpy( pBuffer, m_Buffer->data() + (m_iPosition * samplesize), iFrames * samplesize );
 	m_iPosition += iFrames;
 	

stepmania/src/RageSoundReader_Resample_Good.cpp

@@ -726,6 +726,7 @@ int RageSoundReader_Resample_Good::Read( char *pBuf_, int iFrames )
 			return iFramesRead;
 		}
 
+		// XXX: errors
 		return m_pSource->Read( pBuf_, iFrames );
 	}
 
@@ -735,10 +736,10 @@ int RageSoundReader_Resample_Good::Read( char *pBuf_, int iFrames )
 		ASSERT( pTmpBuf );
 		int iFramesIn = m_pSource->Read( (char *) pTmpBuf, iFramesNeeded );
 
-		if( iFramesIn == -1 )
+		if( iFramesIn < 0 )
 		{
 			SetError( m_pSource->GetError() );
-			return -1;
+			return iFramesIn;
 		}
 
 		const int iSamplesIn = iFramesIn * iChannels;

stepmania/src/RageSoundReader_SpeedChange.cpp

@@ -85,7 +85,7 @@ static int FindClosestMatch( const int16_t *pBuffer, int iBufferSize, const int1
 	return iBestOffset;
 }
 
-void RageSoundReader_SpeedChange::FillData( int iMaxFrames )
+int RageSoundReader_SpeedChange::FillData( int iMaxFrames )
 {
 	/* XXX: If the rate or source frame offset changes in the source, we should stop
 	 * at that point, so the changes propagate upward.  That's tricky, since we want
@@ -97,13 +97,16 @@ void RageSoundReader_SpeedChange::FillData( int iMaxFrames )
 		int iFramesToRead = iMaxFrames - m_iDataBufferAvailFrames;
 		int iBytesToRead = iFramesToRead * m_Channels.size() * sizeof(int16_t);
 		if( iBytesToRead <= 0 )
-			return;
+			return m_iDataBufferAvailFrames;
 
 		int16_t *pTempBuffer = (int16_t *) alloca( iBytesToRead );
 		int iGotFrames = m_pSource->Read( (char *) pTempBuffer, iFramesToRead );
-		// if( iGotFrames == -1 ) XXX
-		if( !iGotFrames )
-			return;
+		if( iGotFrames < 0 )
+		{
+			if( iGotFrames == END_OF_FILE && m_iDataBufferAvailFrames )
+				return m_iDataBufferAvailFrames;
+			return iGotFrames;
+		}
 
 		for( size_t i = 0; i < m_Channels.size(); ++i )
 		{
@@ -124,6 +127,7 @@ void RageSoundReader_SpeedChange::FillData( int iMaxFrames )
 
 		m_iDataBufferAvailFrames += iGotFrames;
 	}
+	return m_iDataBufferAvailFrames;
 }
 
 void RageSoundReader_SpeedChange::EraseData( int iFramesToDelete )
@@ -145,15 +149,10 @@ void RageSoundReader_SpeedChange::EraseData( int iFramesToDelete )
 	}
 }
 
-bool RageSoundReader_SpeedChange::Step()
+int RageSoundReader_SpeedChange::Step()
 {
 	if( m_iDataBufferAvailFrames == 0 )
-	{
-		FillData( GetWindowSizeFrames() );
-		if( m_iDataBufferAvailFrames == 0 )
-			return false;
-		return true;
-	}
+		return FillData( GetWindowSizeFrames() );
 
 	/* If m_iPos is non-zero, we just finished playing a previous block, so advance forward. */
 	if( m_iPos )
@@ -186,15 +185,21 @@ bool RageSoundReader_SpeedChange::Step()
 	EraseData( iToDelete );
 
 	/* Fill as much data as we might need to do the search and use the result. */
-	int iMaxPositionNeeded = m_iUncorrelatedPos + GetToleranceFrames() + GetWindowSizeFrames();
-	for( size_t i = 0; i < m_Channels.size(); ++i )
-		iMaxPositionNeeded = max( iMaxPositionNeeded, m_Channels[i].m_iCorrelatedPos + GetWindowSizeFrames() );
-	FillData( iMaxPositionNeeded );
-	if( iMaxPositionNeeded > m_iDataBufferAvailFrames )
 	{
-		/* We're at EOF.  Flush the remaining data, if any. */
-		m_iUncorrelatedPos = m_Channels[0].m_iCorrelatedPos;
-		return true;
+		int iMaxPositionNeeded = m_iUncorrelatedPos + GetToleranceFrames() + GetWindowSizeFrames();
+		for( size_t i = 0; i < m_Channels.size(); ++i )
+			iMaxPositionNeeded = max( iMaxPositionNeeded, m_Channels[i].m_iCorrelatedPos + GetWindowSizeFrames() );
+
+		int iGot = FillData( iMaxPositionNeeded );
+		if( iGot < 0 )
+			return iGot;
+
+		if( iMaxPositionNeeded > m_iDataBufferAvailFrames )
+		{
+			/* We're at EOF.  Flush the remaining data, if any. */
+			m_iUncorrelatedPos = m_Channels[0].m_iCorrelatedPos;
+			return m_iDataBufferAvailFrames;
+		}
 	}
 
 	/* Starting at our preferred position (m_iUncorrelatedPos), within GetToleranceFrames(),
@@ -214,7 +219,7 @@ bool RageSoundReader_SpeedChange::Step()
 		c.m_iCorrelatedPos = iBest + m_iUncorrelatedPos;
 		ASSERT( m_Channels[i].m_iCorrelatedPos + GetWindowSizeFrames() <= m_iDataBufferAvailFrames );
 	}
-	return true;
+	return m_iDataBufferAvailFrames;
 }
 
 int RageSoundReader_SpeedChange::GetCursorAvail() const
@@ -247,9 +252,11 @@ int RageSoundReader_SpeedChange::Read( char *buf, int iFrames )
 
 		if( iCursorAvail == 0 )
 		{
-			Step();
+			int iRet = Step();
+			if( iRet < 0 )
+				return iRet;
 			if( !GetCursorAvail() )
-				return 0; // EOF
+				return END_OF_FILE;
 			continue;
 		}
 

stepmania/src/RageSoundReader_SpeedChange.h

@@ -25,9 +25,9 @@ public:
 	bool NextReadWillStep() const { return GetCursorAvail() == 0; }
 
 protected:
-	void FillData( int iMax );
+	int FillData( int iMax );
 	void EraseData( int iToDelete );
-	bool Step();
+	int Step();
 	void Reset();
 
 	/* Get the ratio last set by SetSpeedRatio. */

stepmania/src/RageSoundReader_Vorbisfile.cpp

@@ -225,7 +225,7 @@ int RageSoundReader_Vorbisfile::Read( char *buf, int iFrames )
 			if( ret == OV_EBADLINK )
 			{
 				SetError( ssprintf("Read: OV_EBADLINK") );
-				return -1;
+				return ERROR;
 			}
 
 			if( ret == 0 )
@@ -243,6 +243,9 @@ int RageSoundReader_Vorbisfile::Read( char *buf, int iFrames )
 		iFrames -= iFramesRead;
 	}
 
+	if( !frames_read )
+		return END_OF_FILE;
+
 	return frames_read;
 }
 

stepmania/src/RageSoundReader_WAV.cpp

@@ -79,6 +79,9 @@ struct WavReaderPCM: public WavReader
 			len /= 2;
 
 		const int iBytesLeftInDataChunk = m_WavData.m_iDataChunkSize - (m_File.Tell() - m_WavData.m_iDataChunkPos);
+		if( !iBytesLeftInDataChunk )
+			return RageSoundReader::END_OF_FILE;
+
 		len = min( len, iBytesLeftInDataChunk );
 		int iGot = m_File.Read( buf, len );
 		int iGotSamples = 0;
@@ -296,10 +299,15 @@ public:
 			if( m_iBufferUsed == m_iBufferAvail )
 			{
 				if( !DecodeADPCMBlock() )
-					return -1;
+					return RageSoundReader::ERROR;
 			}
 			if( m_iBufferAvail == 0 )
-				break; /* EOF */
+			{
+				if( !iGotFrames )
+					return RageSoundReader::END_OF_FILE;
+				else
+					return iGotFrames;
+			}
 
 			int iFramesToCopy = (m_iBufferAvail-m_iBufferUsed) / iBytesPerFrame;
 			iFramesToCopy = min( iFramesToCopy, (int) (iFrames-iGotFrames) );