public Boolean compress(String fileToRead)
{
initializeBuffer(fileToRead);
Token token;
int slidingWindowOffset = 0;
int currentPosition = 0;
char tokenCharacter;
int tokenOffset = 0;
int tokenLength = 0;
int patternLength = 0;
int i = 0;
int off = 0;
var pos = 0;
while ((currentPosition < entryBuffer.Count()) && (currentPosition < maxNoBitsForLength + entryBuffer.Count()))
{
tokenCharacter = (char)entryBuffer[currentPosition];
if (currentPosition != 0)
{
tokenLength = 0;
tokenOffset = 0;
for (off = 0; off < slidingWindowOffset; off++)
{
i = 0;
patternLength = 0;
pos = currentPosition - off + i - 1;
while ((pos < currentPosition) && (entryBuffer[pos] == entryBuffer[currentPosition + i]) && ((currentPosition + i) < maxNoBitsForLength))
{
i++;
patternLength++;
pos = currentPosition - off + i - 1;
}
if (i > 0)
{
if (patternLength > tokenLength)
{
tokenLength = patternLength;
tokenOffset = off;
tokenCharacter = (char)entryBuffer[currentPosition + i];
}
}
}
currentPosition += tokenLength + 1;
}
else
{
currentPosition++;
}
if ((currentPosition > entryBuffer.Count) && (tokenLength > 0))
{
token = new Token(tokenOffset, tokenLength - 1, (char)entryBuffer[currentPosition - 2]);
tokens.Add(token);
}
else
{
// var te = tokenLength;
token = new Token(tokenOffset, tokenLength, tokenCharacter);
tokens.Add(token);
}
slidingWindowOffset = ((currentPosition - maxNoBitsForOffset) > 0) ? (currentPosition - maxNoBitsForOffset) : (currentPosition);
}
//generate the compressed file
String compressedFile = "File.ext.o" + noBitsForOffset + "l" + noBitsForLength + ".lz77";
BitWriter bitWriter = new BitWriter(compressedFile);
writeTokensToFile(tokens, bitWriter);
return(true);
}
private void writeHeader(BitWriter bitWriter)
{
bitWriter.writeNBits(noBitsForOffset, 5);
bitWriter.writeNBits(noBitsForLength, 3);
}