/// <summary>
/// See <see cref="IByteProvider.InsertBytes" /> for more information.
/// </summary>
public void InsertBytes(long index, byte[] bs)
{
try
{
// Find the block affected.
long blockOffset;
DataBlock block = GetDataBlock(index, out blockOffset);
// If the insertion point is in a memory block, just insert it.
MemoryDataBlock memoryBlock = block as MemoryDataBlock;
if (memoryBlock != null)
{
memoryBlock.InsertBytes(index - blockOffset, bs);
return;
}
FileDataBlock fileBlock = (FileDataBlock)block;
// If the insertion point is at the start of a file block, and the previous block is a memory block, append it to that block.
if (blockOffset == index && block.PreviousBlock != null)
{
MemoryDataBlock previousMemoryBlock = block.PreviousBlock as MemoryDataBlock;
if (previousMemoryBlock != null)
{
previousMemoryBlock.InsertBytes(previousMemoryBlock.Length, bs);
return;
}
}
// Split the block into a prefix and a suffix and place a memory block in-between.
FileDataBlock prefixBlock = null;
if (index > blockOffset)
{
prefixBlock = new FileDataBlock(fileBlock.FileOffset, index - blockOffset);
}
FileDataBlock suffixBlock = null;
if (index < blockOffset + fileBlock.Length)
{
suffixBlock = new FileDataBlock(
fileBlock.FileOffset + index - blockOffset,
fileBlock.Length - (index - blockOffset));
}
block = _dataMap.Replace(block, new MemoryDataBlock(bs));
if (prefixBlock != null)
{
_dataMap.AddBefore(block, prefixBlock);
}
if (suffixBlock != null)
{
_dataMap.AddAfter(block, suffixBlock);
}
}
finally
{
_totalLength += bs.Length;
OnLengthChanged(EventArgs.Empty);
OnChanged(EventArgs.Empty);
}
}
void MoveFileBlock(FileDataBlock fileBlock, long dataOffset)
{
// First, determine whether the next file block needs to move before this one.
long nextDataOffset;
FileDataBlock nextFileBlock = GetNextFileDataBlock(fileBlock, dataOffset, out nextDataOffset);
if (nextFileBlock != null && dataOffset + fileBlock.Length > nextFileBlock.FileOffset)
{
// The next block needs to move first, so do that now.
MoveFileBlock(nextFileBlock, nextDataOffset);
}
// Now, move the block.
if (fileBlock.FileOffset > dataOffset)
{
// Move the section to earlier in the file stream (done in chunks starting at the beginning of the section).
byte[] buffer = new byte[COPY_BLOCK_SIZE];
for (long relativeOffset = 0; relativeOffset < fileBlock.Length; relativeOffset += buffer.Length)
{
long readOffset = fileBlock.FileOffset + relativeOffset;
int bytesToRead = (int)Math.Min(buffer.Length, fileBlock.Length - relativeOffset);
_stream.Position = readOffset;
_stream.Read(buffer, 0, bytesToRead);
long writeOffset = dataOffset + relativeOffset;
_stream.Position = writeOffset;
_stream.Write(buffer, 0, bytesToRead);
}
}
else
{
// Move the section to later in the file stream (done in chunks starting at the end of the section).
byte[] buffer = new byte[COPY_BLOCK_SIZE];
for (long relativeOffset = 0; relativeOffset < fileBlock.Length; relativeOffset += buffer.Length)
{
int bytesToRead = (int)Math.Min(buffer.Length, fileBlock.Length - relativeOffset);
long readOffset = fileBlock.FileOffset + fileBlock.Length - relativeOffset - bytesToRead;
_stream.Position = readOffset;
_stream.Read(buffer, 0, bytesToRead);
long writeOffset = dataOffset + fileBlock.Length - relativeOffset - bytesToRead;
_stream.Position = writeOffset;
_stream.Write(buffer, 0, bytesToRead);
}
}
// This block now points to a different position in the file.
fileBlock.SetFileOffset(dataOffset);
}
/// <summary>
/// See <see cref="IByteProvider.WriteByte" /> for more information.
/// </summary>
public void WriteByte(long index, byte value)
{
try
{
// Find the block affected.
long blockOffset;
DataBlock block = GetDataBlock(index, out blockOffset);
// If the byte is already in a memory block, modify it.
MemoryDataBlock memoryBlock = block as MemoryDataBlock;
if (memoryBlock != null)
{
memoryBlock.Data[index - blockOffset] = value;
return;
}
FileDataBlock fileBlock = (FileDataBlock)block;
// If the byte changing is the first byte in the block and the previous block is a memory block, extend that.
if (blockOffset == index && block.PreviousBlock != null)
{
MemoryDataBlock previousMemoryBlock = block.PreviousBlock as MemoryDataBlock;
if (previousMemoryBlock != null)
{
previousMemoryBlock.AddByteToEnd(value);
fileBlock.RemoveBytesFromStart(1);
if (fileBlock.Length == 0)
{
_dataMap.Remove(fileBlock);
}
return;
}
}
// If the byte changing is the last byte in the block and the next block is a memory block, extend that.
if (blockOffset + fileBlock.Length - 1 == index && block.NextBlock != null)
{
MemoryDataBlock nextMemoryBlock = block.NextBlock as MemoryDataBlock;
if (nextMemoryBlock != null)
{
nextMemoryBlock.AddByteToStart(value);
fileBlock.RemoveBytesFromEnd(1);
if (fileBlock.Length == 0)
{
_dataMap.Remove(fileBlock);
}
return;
}
}
// Split the block into a prefix and a suffix and place a memory block in-between.
FileDataBlock prefixBlock = null;
if (index > blockOffset)
{
prefixBlock = new FileDataBlock(fileBlock.FileOffset, index - blockOffset);
}
FileDataBlock suffixBlock = null;
if (index < blockOffset + fileBlock.Length - 1)
{
suffixBlock = new FileDataBlock(
fileBlock.FileOffset + index - blockOffset + 1,
fileBlock.Length - (index - blockOffset + 1));
}
block = _dataMap.Replace(block, new MemoryDataBlock(value));
if (prefixBlock != null)
{
_dataMap.AddBefore(block, prefixBlock);
}
if (suffixBlock != null)
{
_dataMap.AddAfter(block, suffixBlock);
}
}
finally
{
OnChanged(EventArgs.Empty);
}
}
