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);
}
}