private static void SortNodes(HuffmanNode Node, List <HuffmanNode> Nodes)
{
if (Nodes.Contains(Node) == false)
{
Nodes.Add(Node);
}
if (Node.Left != null)
{
SortNodes(Node.Left, Nodes);
}
if (Node.Right != null)
{
SortNodes(Node.Right, Nodes);
}
}
public void Decompress(string FileName, string path)
{
FileInfo oFileInfo = new FileInfo(FileName);
if (oFileInfo.Exists == true)
{
string sCompressedFileName = String.Format("{0}.compressed", oFileInfo.FullName.Replace(oFileInfo.Extension, ""));
byte[] oBuffer = null;
using (FileStream oFileStream = File.OpenRead(sCompressedFileName))
{
oBuffer = new byte[oFileStream.Length];
oFileStream.Read(oBuffer, 0, oBuffer.Length);
}
// Deserialize binary tree
var root = new HuffmanNode();
using (Stream stream = File.Open(path, FileMode.Open))
{
var bformatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
root = (HuffmanNode)bformatter.Deserialize(stream);
}
// Find the zero node
HuffmanNode oZeroHuffmanNode = root;
while (oZeroHuffmanNode.Left != null)
{
oZeroHuffmanNode = oZeroHuffmanNode.Left;
}
// Unpack the file contents
HuffmanNode oCurrentHuffmanNode = null;
StringBuilder oStringBuilder = new StringBuilder();
for (int i = 0; i < oBuffer.Length; i++)
{
string sBinaryWord = "";
byte oByte = oBuffer[i];
if (oByte == 0)
{
sBinaryWord = oZeroHuffmanNode.BinaryWord;
}
else
{
sBinaryWord = Convert.ToString(oByte, 2);
}
if ((sBinaryWord.Length < 8) && (i < (oBuffer.Length - 1)))
{
// Pad binary word out to 8 places
StringBuilder oBinaryStringBuilder = new StringBuilder(sBinaryWord);
while (oBinaryStringBuilder.Length < 8)
{
oBinaryStringBuilder.Insert(0, "0");
}
sBinaryWord = oBinaryStringBuilder.ToString();
}
// Use the binary word to navigate the tree looking for the value
for (int j = 0; j < sBinaryWord.Length; j++)
{
char cValue = sBinaryWord[j];
if (oCurrentHuffmanNode == null)
{
oCurrentHuffmanNode = root;
}
if (cValue == '0')
{
oCurrentHuffmanNode = oCurrentHuffmanNode.Left;
}
else
{
oCurrentHuffmanNode = oCurrentHuffmanNode.Right;
}
if ((oCurrentHuffmanNode.Left == null) && (oCurrentHuffmanNode.Right == null))
{
// No more child nodes to choose from, so this must be a value node
oStringBuilder.Append(oCurrentHuffmanNode.Value.Value);
oCurrentHuffmanNode = null;
}
}
}
// Write out file
string sUncompressedFileName = Path.Combine(oFileInfo.Directory.FullName, String.Format("{0}.uncompressed", oFileInfo.Name.Replace(oFileInfo.Extension, "")));
if (File.Exists(sUncompressedFileName) == true)
{
File.Delete(sUncompressedFileName);
}
using (StreamWriter oStreamWriter = new StreamWriter(File.OpenWrite(sUncompressedFileName)))
{
oStreamWriter.Write(oStringBuilder.ToString());
}
}
}
