public static void TestBitReaderAndBitWriter(string inputFile, string outputFile)
{
FileInfo file = new FileInfo(inputFile);
int nbr = 8 * (int)file.Length;
Random randomNb = new Random();
using (BitReader bitReader = new BitReader(inputFile))
using (BitWriter bitWriter = new BitWriter(outputFile))
{
while (nbr > 0)
{
int nb = randomNb.Next(31) + 1;
if (nb > nbr)
{
nb = nbr;
}
int bitSequence = bitReader.readNBits(nb);
bitWriter.WriteNBits(bitSequence, nb);
nbr -= nb;
}
bitWriter.WriteNBits(0, 7);
}
}
public void Compress(string inputFile, string outputFile)
{
FileInfo file = new FileInfo(inputFile);
int numberOfBits = 8 * (int)file.Length;
int indexMaxSize = Convert.ToInt32(Math.Pow(2, _index)) - 1;
using (BitReader bitReader = new BitReader(inputFile))
using (BitWriter bitWriter = new BitWriter(outputFile))
{
bitWriter.WriteBit(_inghetare ? 1 : 0);
bitWriter.WriteNBits(_index, 4);
string s = "";
char ch;
while (numberOfBits > 0)
{
ch = Convert.ToChar(bitReader.readNBits(8));
numberOfBits -= 8;
int firstOccurence = _symbolList.IndexOf(s + ch);
if (firstOccurence != -1 && firstOccurence <= indexMaxSize)
{
s += ch;
}
else
{
Encode(s, bitWriter);
if (_symbolList.Count > indexMaxSize)
{
if (!_inghetare)
{
_symbolList.Clear();
for (int i = 0; i < 256; i++)
{
_symbolList.Add(((char)i).ToString());
}
}
}
_symbolList.Add(s + ch);
s = Convert.ToString(ch);
}
}
Encode(s, bitWriter);
bitWriter.WriteNBits(0, 7);
}
}
private void Write(string s, BitWriter bitWriter)
{
for (int i = 0; i < s.Length; i++)
{
bitWriter.WriteNBits(Convert.ToInt32(Convert.ToChar(s[i])), 8);
}
}
private void WriteCharFrequencyOn4Bytes(BitWriter bitWriter)
{
foreach (int cFrequency in _charFrequency)
{
if (cFrequency != 0)
{
bitWriter.WriteNBits(cFrequency, 32);
}
}
}
public void Decompress(string inputFile, string outputFile)
{
FileInfo file = new FileInfo(inputFile);
int numberOfBits = (int)file.Length * 8;
bufferD = new byte[file.Length];
using (BitReader bitReader = new BitReader(inputFile))
using (BitWriter bitWriter = new BitWriter(outputFile))
{
int searchbufferLength, lookAheadBufferlength;
searchbufferLength = bitReader.readNBits(5);
lookAheadBufferlength = bitReader.readNBits(3);
int position, length, ch, indexD = 0;
while (numberOfBits > 0)
{
position = bitReader.readNBits(8);
length = bitReader.readNBits(8);
ch = bitReader.readNBits(8);
numberOfBits -= 24;
if (length == 0)
{
bitWriter.WriteNBits(ch, 8);
bufferD[indexD++] = Convert.ToByte(ch);
}
else
{
for (int i = indexD - position - 1; i < length; i++)
{
bufferD[indexD++] = bufferD[i];
bitWriter.WriteNBits(bufferD[i], 8);
}
bufferD[indexD++] = Convert.ToByte(ch);
bitWriter.WriteNBits(ch, 8);
}
}
}
}
public void Decompress(string inputFile, string outputFile)
{
FileInfo file = new FileInfo(inputFile);
int numberOfBits = 8 * (int)file.Length;
using (BitReader bitReader = new BitReader(inputFile))
using (BitWriter bitWriter = new BitWriter(outputFile))
{
bool inghetareD = bitReader.readNBits(1) == 1;
int indexD = bitReader.readNBits(4);
numberOfBits -= 5;
string s = "";
int indexMaxSize = Convert.ToInt32(Math.Pow(2, indexD)) - 1;
int chIndex;
chIndex = bitReader.readNBits(indexD);
numberOfBits -= indexD;
s = _decompressSymbolList[chIndex];
bitWriter.WriteNBits(Convert.ToInt32(Convert.ToChar(s)), s.Length * 8);
string entry = "";
while (numberOfBits >= indexD)
{
chIndex = bitReader.readNBits(indexD);
numberOfBits -= indexD;
if (chIndex >= _decompressSymbolList.Count)
{
entry = s + s[0];
}
else
{
entry = _decompressSymbolList[chIndex];
}
Write(entry, bitWriter);
if (_decompressSymbolList.Count > indexMaxSize)
{
if (!inghetareD)
{
_decompressSymbolList.Clear();
for (int i = 0; i < 256; i++)
{
_decompressSymbolList.Add(((char)i).ToString());
}
}
}
_decompressSymbolList.Add(s + entry[0]);
s = entry;
}
}
}
private void Write(string inputFile, string outputFile)
{
using (BitWriter bitWriter = new BitWriter(outputFile))
{
//header
WriteAlocationMap(bitWriter);
WriteCharFrequencyOn4Bytes(bitWriter);
FileInfo file = new FileInfo(inputFile);
int numberOfBits = 8 * (int)file.Length;
using (BitReader bitReader = new BitReader(inputFile))
{
while (numberOfBits > 0)
{
int character = bitReader.readNBits(8);
bitWriter.WriteNBits(_charCode[character], _codeLength[character]);
numberOfBits -= 8;
}
bitWriter.WriteNBits(0, 7);
}
}
}
private void DecodeAndWrite(BitReader bitReader, int fileLength, TreeNode <KeyValuePair <int, int> > huffmanTree, BitWriter bitWriter)
{
TreeNode <KeyValuePair <int, int> > currentNode;
for (int i = 0; i < fileLength; i++)
{
currentNode = huffmanTree;
while (!currentNode.IsLeaf())
{
int bit = bitReader.readBit();
currentNode = bit == 0 ? currentNode.leftChild : currentNode.rightChild;
}
//scrie caracterul
int decodedChar = currentNode.value.Key;
bitWriter.WriteNBits(decodedChar, 8);
}
}
private void Encode(string s, BitWriter bitWriter)
{
bitWriter.WriteNBits(_symbolList.IndexOf(s.ToString()), _index);
}
private void WriteToken(BitWriter bitWriter, int position, int length, int character)
{
bitWriter.WriteNBits(position, _p);
bitWriter.WriteNBits(length, _l);
bitWriter.WriteNBits(character, 8);
}
