public void Encode(Stream input, Stream output)
{
var rootNode = _treeBuilder.Build(input.ToArray(), _bitDepth, _byteOrder);
// For a more even distribution of the children over the branches, we'll label the tree nodes
var labelList = LabelTreeNodes(rootNode);
// Create huffman bit codes
var bitCodes = labelList[0].GetHuffCodes().ToDictionary(node => node.Item1, node => node.Item2);
// Write header + tree
using (var bw = new BinaryWriter(output))
{
// Write header
var header = new[] { (byte)(0x20 + _bitDepth), (byte)(input.Length & 0xFF), (byte)((input.Length >> 8) & 0xFF), (byte)((input.Length >> 16) & 0xFF) };
bw.Write(header, 0, 4);
bw.Write((byte)labelList.Count);
// Write Huffman tree
foreach (var node in labelList.Take(1).Concat(labelList.SelectMany(node => node.Children)))
{
if (node.Children != null)
{
node.Code |= node.Children.Select((child, i) => child.IsLeaf ? (byte)(0x80 >> i) : 0).Sum();
}
bw.Write((byte)node.Code);
}
// Write bits to stream
using (var bitWriter = new BitWriter(bw.BaseStream, BitOrder.MsbFirst, 4, ByteOrder.LittleEndian))
{
switch (_bitDepth)
{
case 4:
while (input.Position < input.Length)
{
var value = input.ReadByte();
if (_byteOrder == ByteOrder.LittleEndian)
{
foreach (var bit in bitCodes[value % 16])
{
bitWriter.WriteBit(bit - '0');
}
foreach (var bit in bitCodes[value / 16])
{
bitWriter.WriteBit(bit - '0');
}
}
else
{
foreach (var bit in bitCodes[value / 16])
{
bitWriter.WriteBit(bit - '0');
}
foreach (var bit in bitCodes[value % 16])
{
bitWriter.WriteBit(bit - '0');
}
}
}
break;
case 8:
while (input.Position < input.Length)
{
var value = input.ReadByte();
foreach (var bit in bitCodes[value])
{
bitWriter.WriteBit(bit - '0');
}
}
break;
}
bitWriter.Flush();
}
}
}
private HuffmanTreeNode CreateDisplacementIndexTree(Block block, IHuffmanTreeBuilder treeBuilder)
{
return(treeBuilder.Build(block.dispIndexes, 8, NibbleOrder.LowNibbleFirst));
}
private HuffmanTreeNode CreateRawValueTree(Stream input, Match[] matches, IHuffmanTreeBuilder treeBuilder)
{
var huffmanInput = RemoveMatchesFromInput(input.ToArray(), matches);
return(treeBuilder.Build(huffmanInput, 8, NibbleOrder.LowNibbleFirst));
}
private HuffmanTreeNode CreateIndexValueTree(Block block, IHuffmanTreeBuilder treeBuilder)
{
return(treeBuilder.Build(block.countIndexes, 8, NibbleOrder.LowNibbleFirst));
}
private HuffmanTreeNode CreateRawValueTree(Stream input, Match[] matches)
{
var huffmanInput = RemoveMatchesFromInput(input.ToArray(), matches);
return(_treeBuilder.Build(huffmanInput, 8, ByteOrder.LittleEndian));
}