1 files changed, 262 insertions, 0 deletions
diff --git a/lib/common/ReadGatherStream.cpp b/lib/common/ReadGatherStream.cpp
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+++ b/lib/common/ReadGatherStream.cpp
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+// --------------------------------------------------------------------------
+//
+// File
+//		Name:    ReadGatherStream.cpp
+//		Purpose: Build a stream (for reading only) out of a number of other streams.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+
+#include "Box.h"
+
+#include "ReadGatherStream.h"
+#include "CommonException.h"
+
+#include "MemLeakFindOn.h"
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::ReadGatherStream(bool)
+//		Purpose: Constructor. Args says whether or not all the component streams will be deleted when this
+//				 object is deleted.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+ReadGatherStream::ReadGatherStream(bool DeleteComponentStreamsOnDestruction)
+	: mDeleteComponentStreamsOnDestruction(DeleteComponentStreamsOnDestruction),
+	  mCurrentPosition(0),
+	  mTotalSize(0),
+	  mCurrentBlock(0),
+	  mPositionInCurrentBlock(0),
+	  mSeekDoneForCurrent(false)
+{
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::~ReadGatherStream()
+//		Purpose: Destructor. Will delete all the stream objects, if required.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+ReadGatherStream::~ReadGatherStream()
+{
+	// Delete compoenent streams?
+	if(mDeleteComponentStreamsOnDestruction)
+	{
+		for(unsigned int l = 0; l < mComponents.size(); ++l)
+		{
+			delete mComponents[l];
+		}
+	}
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::AddComponent(IOStream *)
+//		Purpose: Add a component to this stream, returning the index of this component
+//				 in the internal list. Use this with AddBlock()
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+int ReadGatherStream::AddComponent(IOStream *pStream)
+{
+	ASSERT(pStream != 0);
+
+	// Just add the component to the list, returning it's index.
+	int index = mComponents.size();
+	mComponents.push_back(pStream);
+	return index;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::AddBlock(int, pos_type, bool, pos_type)
+//		Purpose: Add a block to the list of blocks being gathered into one stream.
+//				 Length is length of block to read from this component, Seek == true
+//				 if a seek is required, and if true, SeekTo is the position (absolute)
+//				 in the stream to be seeked to when this block is required.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+void ReadGatherStream::AddBlock(int Component, pos_type Length, bool Seek, pos_type SeekTo)
+{
+	// Check block
+	if(Component < 0 || Component >= (int)mComponents.size() || Length < 0 || SeekTo < 0)
+	{
+		THROW_EXCEPTION(CommonException, ReadGatherStreamAddingBadBlock);
+	}
+	
+	// Add to list
+	Block b;
+	b.mLength = Length;
+	b.mSeekTo = SeekTo;
+	b.mComponent = Component;
+	b.mSeek = Seek;
+	
+	mBlocks.push_back(b);
+	
+	// And update the total size
+	mTotalSize += Length;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::Read(void *, int, int)
+//		Purpose: As interface.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+int ReadGatherStream::Read(void *pBuffer, int NBytes, int Timeout)
+{
+	int bytesToRead = NBytes;
+	uint8_t *buffer = (uint8_t*)pBuffer;
+	
+	while(bytesToRead > 0)
+	{
+		// Done?
+		if(mCurrentBlock >= mBlocks.size())
+		{
+			// Stop now, as have finished the last block
+			return NBytes - bytesToRead;
+		}
+			
+		// Seek?
+		if(mPositionInCurrentBlock == 0 && mBlocks[mCurrentBlock].mSeek && !mSeekDoneForCurrent)
+		{
+			// Do seeks in this manner so that seeks are done regardless of whether the block
+			// has length > 0, and it will only be done once, and at as late a stage as possible.
+			
+			mComponents[mBlocks[mCurrentBlock].mComponent]->Seek(mBlocks[mCurrentBlock].mSeekTo, IOStream::SeekType_Absolute);
+		
+			mSeekDoneForCurrent = true;
+		}
+
+		// Anything in the current block?
+		if(mPositionInCurrentBlock < mBlocks[mCurrentBlock].mLength)
+		{
+			// Read!
+			int s = mBlocks[mCurrentBlock].mLength - mPositionInCurrentBlock;
+			if(s > bytesToRead) s = bytesToRead;
+			
+			int r = mComponents[mBlocks[mCurrentBlock].mComponent]->Read(buffer, s, Timeout);
+			
+			// update variables
+			mPositionInCurrentBlock += r;
+			buffer += r;
+			bytesToRead -= r;
+			mCurrentPosition += r;
+			
+			if(r != s)
+			{
+				// Stream returned less than requested. To avoid blocking when not necessary,
+				// return now.
+				return NBytes - bytesToRead;
+			}
+		}
+		else
+		{
+			// Move to next block
+			++mCurrentBlock;
+			mPositionInCurrentBlock = 0;
+			mSeekDoneForCurrent = false;
+		}
+	}
+
+	return NBytes - bytesToRead;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::GetPosition()
+//		Purpose: As interface
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+IOStream::pos_type ReadGatherStream::GetPosition() const
+{
+	return mCurrentPosition;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::BytesLeftToRead()
+//		Purpose: As interface
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+IOStream::pos_type ReadGatherStream::BytesLeftToRead()
+{
+	return mTotalSize - mCurrentPosition;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::Write(const void *, int)
+//		Purpose: As interface.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+void ReadGatherStream::Write(const void *pBuffer, int NBytes)
+{
+	THROW_EXCEPTION(CommonException, CannotWriteToReadGatherStream);
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::StreamDataLeft()
+//		Purpose: As interface.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+bool ReadGatherStream::StreamDataLeft()
+{
+	if(mCurrentBlock >= mBlocks.size())
+	{
+		// Done all the blocks
+		return false;
+	}
+	
+	if(mCurrentBlock == (mBlocks.size() - 1)
+		&& mPositionInCurrentBlock >= mBlocks[mCurrentBlock].mLength)
+	{
+		// Are on the last block, and have got all the data from it.
+		return false;
+	}
+
+	// Otherwise, there's more data to be read
+	return true;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    ReadGatherStream::StreamClosed()
+//		Purpose: As interface. But the stream is always closed.
+//		Created: 10/12/03
+//
+// --------------------------------------------------------------------------
+bool ReadGatherStream::StreamClosed()
+{
+	return true;
+}
+
+