public Boolean compress(String fileToRead)
{
BitReader bitReader = new BitReader(fileToRead);
FileInfo f = new FileInfo(fileToRead);
int nbr = 8 * (int)f.Length;
fillDictionaryFixedPart(symbolDictionary);
String symbol = "";
List <String> list;
int currentPosition = symbolDictionary.Count();
while (nbr > 0)
{
int character = bitReader.readNBits(8);
var c = (char)character;
var charString = c.ToString();
int charIndex = getIndexFromDictionary(symbolDictionary, symbol + charString);
if ((charIndex != -1) && (charIndex <= indexMaxSize))
{
symbol = symbol + charString;
}
else
{
if (symbolDictionary.Count > indexMaxSize)
{
if (freeze == 0)
{
symbolDictionary.Clear();
fillDictionaryFixedPart(symbolDictionary);
}
}
list = new List <string>();
list.Add(symbol + charString);
list.Add(symbol);
symbolDictionary.Add(currentPosition, list);
currentPosition++;
symbol = charString;
}
nbr -= 8;
if (nbr <= 0)
{
list = new List <string>();
list.Add(symbol + charString);
list.Add(symbol);
symbolDictionary.Add(currentPosition, list);
}
}
bitReader.cleanUp();
String compressedFile = "File.ext." + ((freeze == 1) ? "f" : "e") + "l" + index + ".lzw";
BitWriter bitWriter = new BitWriter(compressedFile);
writeCompressedFile(symbolDictionary, bitWriter);
bitWriter.cleanUp();
return(true);
}
private void writeCompressedFile(Dictionary <int, List <String> > symbolDictionary, BitWriter bitWriter)
{
writeheader(bitWriter);
Dictionary <int, List <String> > dictionaryFromInput = getDictionaryElements();
int valueIndex = 0;
foreach (KeyValuePair <int, List <String> > symbol in dictionaryFromInput)
{
var element = (symbol.Key != noOfSymbols) ? symbol.Value[1] : symbol.Value[0][0].ToString();
valueIndex = getIndexFromDictionary(symbolDictionary, element);
bitWriter.writeNBits(valueIndex, index);
}
bitWriter.writeNBits(0, 7);
}
private void writeheader(BitWriter bitWriter)
{
bitWriter.writeBit(freeze);
bitWriter.writeNBits(index, 4);
}
public Boolean decompress(String compressedFileToRead)
{
BitReader bitReader = new BitReader(compressedFileToRead);
FileInfo f = new FileInfo(compressedFileToRead);
int nbr = 8 * (int)f.Length;
symbolDecompressDictionary = new Dictionary <int, List <string> >();
fillDictionaryFixedPart(symbolDecompressDictionary);
String symbol = "";
List <String> list;
int currentPosition = noOfSymbols;
int[] headerData = getDataFromHeader(bitReader, nbr);
nbr -= 5;
this.freeze = headerData[0];
this.index = headerData[1];
int characterIndex = bitReader.readNBits(index);
var charString = symbolDecompressDictionary[characterIndex][0];
decompressedResult.Add(charString);
symbol = charString;
nbr -= index;
while (nbr >= index + 8)
{
characterIndex = bitReader.readNBits(index);
if (characterIndex >= symbolDecompressDictionary.Count)
{
charString = symbol + symbol[0];
}
else
{
charString = symbolDecompressDictionary[characterIndex][0];
}
decompressedResult.Add(charString);
if (symbolDictionary.Count > indexMaxSize)
{
if (freeze == 0)
{
symbolDecompressDictionary.Clear();
fillDictionaryFixedPart(symbolDecompressDictionary);
}
}
list = new List <string>();
list.Add(symbol + charString[0]);
symbolDecompressDictionary.Add(currentPosition, list);
currentPosition++;
symbol = charString;
nbr -= index;
}
//generate the decompressed file
String decompressedFile = "File.ext." + ((freeze == 1) ? "f" : "e") + "l" + index + ".lzw.ext";
BitWriter bitWriter = new BitWriter(decompressedFile);
writeDecompressedDataToFile(decompressedResult, bitWriter);
bitWriter.cleanUp();
return(true);
}
