bool Extract()
{
fsin.Seek(0, SeekOrigin.Begin);
for (int i = 0; i < 256; i++)
{
huffLength[i] = fsin.ReadByte();
huffCode[i] = (byte)fsin.ReadByte();
if (huffLength[i] > 0)
{
InsertIntoHuffTree(i);
}
}
oriFileSize = 0;
for (int i = 0; i < 8; i++)
{
oriFileSize <<= 8;
oriFileSize |= (long)(fsin.ReadByte() & 0xFF);
}
uint bit = 0;
HuffmanNode node = headNode;
ReadBitFromFile(ref bit);
do
{
while (node.mLeft != null && node.mRight != null)
{
if (bit == 0)
{
node = node.mLeft;
}
else
{
node = node.mRight;
}
ReadBitFromFile(ref bit);
}
fsout.WriteByte(node.mValue);
node = headNode;
}while (fsout.Position < oriFileSize);
return(true);
}
void InsertIntoHuffTree(int value)
{
try
{
if (headNode == null)
{
headNode = new HuffmanNode();
}
HuffmanNode curNode = headNode;
int length = huffLength[value];
uint code = huffCode[value];
while (length > 0)
{
uint bit = (code >> length - 1) & ~(~0 << 1);
if (bit == 0)
{
if (curNode.mLeft == null)
{
curNode.mLeft = new HuffmanNode();
}
curNode = curNode.mLeft;
}
else
{
if (curNode.mRight == null)
{
curNode.mRight = new HuffmanNode();
}
curNode = curNode.mRight;
}
length--;
}
curNode.mValue = (byte)value;
}
catch (Exception ex)
{
Console.WriteLine(ex.StackTrace + ", (" + ex.Message + ")");
}
}
public void MakeHuffmanTree()
{
nodeCount = 0;
for (int i = 0; i < 256; i++)
{
if (freq[i] > 0)
{
HuffmanNode node = new HuffmanNode();
node.mValue = (byte)i;
node.mFreq = freq[i];
node.mRight = null;
node.mLeft = null;
nodeCount++;
huffList[nodeCount - 1] = node;
}
}
int head = nodeCount;
while (head > 1)
{
int min = FindMinFrequency(head);
HuffmanNode node1 = huffList[min];
head--;
huffList[min] = huffList[head];
min = FindMinFrequency(head);
HuffmanNode node2 = huffList[min];
HuffmanNode node = new HuffmanNode();
node.mValue = 0;
node.mFreq = node1.mFreq + node2.mFreq;
node.mLeft = node1;
node.mRight = node2;
huffList[min] = node;
}
headNode = huffList[0];
}
public void MakeCode(HuffmanNode node, uint code, int length)
{
if (node.mLeft == null && node.mRight == null)
{
huffCode[node.mValue] = code;
huffLength[node.mValue] = length;
}
else
{
code = code << 1;
length++;
MakeCode(node.mLeft, code, length);
code = code | 1u;
MakeCode(node.mRight, code, length);
code = code >> 1;
length--;
}
}
private void DeleteHuffTree()
{
Stack <HuffmanNode> nodes = new Stack <HuffmanNode>();
nodes.Push(headNode);
while (nodes.Count > 0)
{
HuffmanNode i = nodes.Pop();
if (i.mRight != null)
{
nodes.Push(i.mRight);
}
if (i.mLeft != null)
{
nodes.Push(i.mLeft);
}
i.DeleteNode();
}
for (int i = 0; i < 256; i++)
{
huffList[i] = null;
freq[i] = 0;
huffCode[i] = 0;
huffLength[i] = 0;
}
cmpByte = 0;
cmpBit = 7;
extByte = 0;
extBit = -1;
}
