VAR/VAR.UrlCompressor
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Huffman: Refactor EncodeChar.

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Valeriano A.R.
2017-07-12 23:59:11 +02:00
parent a43a517a28
commit 39b62740c8
1 changed files with 31 additions and 26 deletions
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57
VAR.UrlCompressor/Huffman.cs
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@@ -65,32 +65,36 @@ namespace VAR.UrlCompressor
} }
} }
private int _bitPosition = 0;
private List<bool> _encodedSymbol = new List<bool>();
private byte[] _scratch = null;
private void EncodeChar(char data)
{
_encodedSymbol.Clear();
_encodedSymbol = Root.Traverse(data, _encodedSymbol);
foreach (bool v in _encodedSymbol)
{
_scratch.WriteBit(_bitPosition, 0, v);
_bitPosition++;
}
}
public byte[] Encode(byte[] data) public byte[] Encode(byte[] data)
{ {
byte[] scratch = new byte[data.Length * 2]; _scratch = new byte[data.Length * 2];
int bitPosition = 0; _bitPosition = 0;
var encodedSymbol = new List<bool>();
for (int i = 0; i < data.Length; i++) for (int i = 0; i < data.Length; i++)
{ {
encodedSymbol.Clear(); EncodeChar((char)data[i]);
encodedSymbol = Root.Traverse((char)data[i], encodedSymbol);
foreach(bool v in encodedSymbol)
{
scratch.WriteBit(bitPosition, 0, v);
bitPosition++;
}
} }
encodedSymbol.Clear(); EncodeChar(EOD);
encodedSymbol = Root.Traverse(EOD, encodedSymbol);
foreach (bool v in encodedSymbol) int byteLenght = (int)Math.Ceiling((double)_bitPosition / 8);
{
scratch.WriteBit(bitPosition, 0, v);
bitPosition++;
}
int byteLenght = (int)Math.Ceiling((double)bitPosition / 8);
byte[] compressedData = new byte[byteLenght]; byte[] compressedData = new byte[byteLenght];
Array.Copy(scratch, compressedData, byteLenght); Array.Copy(_scratch, compressedData, byteLenght);
_scratch = null;
return compressedData; return compressedData;
} }
@@ -98,15 +102,15 @@ namespace VAR.UrlCompressor
public byte[] Decode(byte[] data) public byte[] Decode(byte[] data)
{ {
HuffmanTreeNode current = Root; HuffmanTreeNode current = Root;
byte[] scratch = new byte[data.Length]; _scratch = new byte[data.Length];
int bitPosition = 0; _bitPosition = 0;
int bytePosition = 0; int bytePosition = 0;
int lenght = data.Length * 8; int lenght = data.Length * 8;
while (bitPosition < lenght) while (_bitPosition < lenght)
{ {
bool bit = data.ReadBit(bitPosition, 0); bool bit = data.ReadBit(_bitPosition, 0);
bitPosition++; _bitPosition++;
if (bit) if (bit)
{ {
if (current.Right != null) if (current.Right != null)
@@ -125,14 +129,15 @@ namespace VAR.UrlCompressor
if (current.IsLeaf()) if (current.IsLeaf())
{ {
if (current.Symbol == EOD) { break; } if (current.Symbol == EOD) { break; }
scratch = scratch.WriteByte(bytePosition, (byte)current.Symbol); _scratch = _scratch.WriteByte(bytePosition, (byte)current.Symbol);
bytePosition++; bytePosition++;
current = Root; current = Root;
} }
} }
byte[] decompressedData = new byte[bytePosition]; byte[] decompressedData = new byte[bytePosition];
Array.Copy(scratch, decompressedData, bytePosition); Array.Copy(_scratch, decompressedData, bytePosition);
_scratch = null;
return decompressedData; return decompressedData;
} }