public bool Decode(Stream Data, string OutputFile)
{
Data.Seek(0, SeekOrigin.Begin);
FileHeader Header;
if (!IsArchivedStream(Data))
{
throw new Exception("The given stream is't my Huffman algorithm type.");
}
Header = (FileHeader)BinFormat.Deserialize(Data);
HuffmanTree huffmanTree = new HuffmanTree(Header.frequencyTable);
FileStream tempFS = new FileStream(OutputFile, FileMode.Create);
BitsStack Stack = new BitsStack();
long DataSize = Data.Length - Data.Position;
if (Header.ComplementsBits == 0)
{
DataSize += 1;
}
TreeNode TempNode = null;
while (true)
{
TempNode = huffmanTree.RootNode;
//Пока это не лист, идти вниз по дереву
while (TempNode.Left != null && TempNode.Right != null)
{
//Если стек пуст пополнить его.
if (Stack.IsEmpty())
{
Stack.FillStack((Byte)Data.ReadByte());
if ((--DataSize) == 0)
{
goto AlmostDone;
}
}
//влево или вправо в соответствии с битом
TempNode = Stack.PopFlag() ? TempNode.Left : TempNode.Right;
}
tempFS.WriteByte(TempNode.ByteValue);
}
AlmostDone:
short BitsLeft = (Byte)(Stack.NumOfBits() - Header.ComplementsBits);
// отдать остальную часть последнего байта.
if (BitsLeft != 8)
{
bool Test = TempNode.Left == null && TempNode.Right == null;
while (BitsLeft > 0)
{
// Если в itteration, TempNode не сделали спускаясь дерево Хаффмана.
if (Test)
{
TempNode = huffmanTree.RootNode;
}
while (TempNode.Left != null && TempNode.Right != null)
{
//влево или вправо в соответствии с битом
TempNode = Stack.PopFlag() ? TempNode.Left : TempNode.Right;
--BitsLeft;
}
// к листу и записать данные.
tempFS.WriteByte(TempNode.ByteValue);
Test = true;
}
}
tempFS.Close();
return(true);
}
public Stream Decode(Stream Data)
{
Data.Seek(0, SeekOrigin.Begin);
//Tempdirectory
String TempDir = Environment.GetEnvironmentVariable("temp");
FileHeader Header;
//Reading the header data from the stream
if (!IsArchivedStream(Data))
{
throw new Exception("The given stream is't Huffmans algorithm archive type.");
}
Header = (FileHeader)BinFormat.Deserialize(Data);
//Gernerating Huffman tree out of the frequency table in the header
HuffmanTree huffmanTree = new HuffmanTree(Header.frequencyTable);
//Creating temporary file
FileStream tempFS = new FileStream(TempDir + @"\TempArch.tmp", FileMode.Create);
BitsStack Stack = new BitsStack();
long DataSize = Data.Length - Data.Position;
if (Header.ComplementsBits == 0)
{
DataSize += 1;
}
TreeNode TempNode = null;
while (true)
{
TempNode = huffmanTree.RootNode;
//As long it's not a leaf, go down the tree
while (TempNode.Left != null && TempNode.Right != null)
{
//If the stack is empty refill it.
if (Stack.IsEmpty())
{
Stack.FillStack((Byte)Data.ReadByte());
if ((--DataSize) == 0)
{
goto AlmostDone;
}
}
//Going left or right according to the bit
TempNode = Stack.PopFlag() ? TempNode.Left : TempNode.Right;
}
//By now reached for a leaf and writes it's data.
tempFS.WriteByte(TempNode.ByteValue);
} //end of while
//To this lable u can jump only from the while loop (only one byte left).
AlmostDone:
short BitsLeft = (Byte)(Stack.NumOfBits() - Header.ComplementsBits);
//Writing the rest of the last byte.
if (BitsLeft != 8)
{
bool Test = TempNode.Left == null && TempNode.Right == null;
while (BitsLeft > 0)
{
//If at itteration, TempNode not done going down the huffman tree.
if (Test)
{
TempNode = huffmanTree.RootNode;
}
while (TempNode.Left != null && TempNode.Right != null)
{
//Going left or right according to the bit
TempNode = Stack.PopFlag() ? TempNode.Left : TempNode.Right;
--BitsLeft;
}
//By now reached for a leaf and writes it's data.
tempFS.WriteByte(TempNode.ByteValue);
Test = true;
}
}
tempFS.Seek(0, SeekOrigin.Begin);
return(tempFS);
}
