public byte[] DecompressData(byte[] compressedData, int tailZeroCount)
{
LogUtil.Log("Decompressing data...");
List <byte> originalData = new List <byte>();
int remainBitsInByte = 8;
long operatingByteIndex = 0;
byte operatingByte = compressedData[0];
HuffmanNode currentNode = RootNode;
while (true)
{
// Check if reached the end of data
if (operatingByteIndex == compressedData.LongLength - 1 &&
remainBitsInByte == tailZeroCount % 8)
{
return(originalData.ToArray());
}
// Get the highest bit of current byte as part of path
currentNode = (operatingByte >> 7) == L_BIT ? currentNode.LeftChild : currentNode.RightChild;
// If leaf node is found, get original byte of string and reset current node
if (currentNode.IsLeafNode)
{
originalData.Add(currentNode.NodeValue);
currentNode = RootNode;
}
// Check if need to move to next bit
remainBitsInByte--;
if (remainBitsInByte == 0)
{
remainBitsInByte = 8;
operatingByteIndex++;
//Console.WriteLine(compressedData.LongLength - operatingByteIndex);
if (operatingByteIndex == compressedData.LongLength)
{
return(originalData.ToArray());
}
operatingByte = compressedData[operatingByteIndex];
}
else
{
operatingByte <<= 1;
}
}
}
/// <summary>
/// Visit all nodes recursively and save the path of leaf node to path dictionary
/// </summary>
/// <param name="node">Next node</param>
/// <param name="nextString">String for next node</param>
/// <param name="pathDictionary">Dictionary for saving all strings</param>
private void GetPathOfNodeAndChildren(HuffmanNode node, string nextString,
Dictionary <byte, string> pathDictionary)
{
if (node.IsLeafNode)
{
// Save current string to dict
pathDictionary.Add(node.NodeValue, nextString);
}
if (node.LeftChild != null)
{
// If has left child, visit it
GetPathOfNodeAndChildren(node.LeftChild, nextString + "L", pathDictionary);
}
if (node.RightChild != null)
{
// If has right child, visit it
GetPathOfNodeAndChildren(node.RightChild, nextString + "R", pathDictionary);
}
}
