public void TryToFillSearchBufferBasedOnLz77Token(Lz77Buffer lz77Buffer, Lz77Token lz77Token)
{
if (lz77Buffer == null)
{
throw new ArgumentNullException(nameof(lz77Buffer));
}
if (lz77Token == null)
{
throw new ArgumentNullException(nameof(lz77Token));
}
for (int index = 0; index < lz77Token.Length + 1; index++)
{
if (index > lz77Buffer.LookAheadBuffer.Count - 1)
{
break;
}
if (lz77Buffer.SearchBuffer.Count >= lz77Buffer.SearchBuffer.Capacity)
{
lz77Buffer.SearchBuffer.RemoveAt(0);
}
lz77Buffer.SearchBuffer.Add(lz77Buffer.LookAheadBuffer[index]);
}
}
private void InitializeLz77TokenExtractorMock()
{
lz77TokenReturnedByLz77TokenExtractor = new Lz77Token();
lz77TokenExtractorMock
.Setup(x => x.GetLz77TokenFromLz77Buffer(lz77Encoder.Lz77Buffer))
.Returns(lz77TokenReturnedByLz77TokenExtractor);
}
public void Setup()
{
lz77TokenWriter = new Lz77TokenWriter();
lz77Token = new Lz77Token {
Position = 4, Length = 5, Byte = 31
};
fileWriterMock = new Mock <IFileWriter>();
}
public void Setup()
{
lz77BufferManager = new Lz77BufferManager();
lz77Buffer = Constants.GetLz77Buffer1();
lz77Token = Constants.ExpectedTokenForLz77Buffer1();
fileReaderMock = new Mock <IFileReader>();
SetupFileReaderMock();
}
public void WriteToken(Lz77Token lz77Token, IFileWriter fileWriter, int bitsForOffset, int bitsForLength)
{
if (lz77Token == null)
{
throw new ArgumentNullException(nameof(lz77Token));
}
if (fileWriter == null)
{
throw new ArgumentNullException(nameof(fileWriter));
}
fileWriter.WriteValueOnBits((uint)lz77Token.Position, (byte)bitsForOffset);
fileWriter.WriteValueOnBits((uint)lz77Token.Length, (byte)bitsForLength);
fileWriter.WriteValueOnBits(lz77Token.Byte, 8);
}
private List <byte> GetBytesFromBufferBasedOnToken(List <byte> buffer, Lz77Token lz77Token)
{
var bytes = new List <byte>();
var position = buffer.Count - 1 - lz77Token.Position;
position = position < 0 ? 0 : position;
for (int i = 0; i < lz77Token.Length; i++)
{
bytes.Add(buffer[position]);
position++;
}
return(bytes);
}
public void EmptyLookAheadBufferBasedOnLz77Token(Lz77Buffer lz77Buffer, Lz77Token lz77Token)
{
if (lz77Buffer == null)
{
throw new ArgumentNullException(nameof(lz77Buffer));
}
if (lz77Token == null)
{
throw new ArgumentNullException(nameof(lz77Token));
}
var bytesToRemove = lz77Token.Length + 1;
while (bytesToRemove > 0 && lz77Buffer.LookAheadBuffer.Count > 0)
{
lz77Buffer.LookAheadBuffer.RemoveAt(0);
bytesToRemove--;
}
}
public void DecodeFile(IFileReader fileReader, IFileWriter fileWriter)
{
TokensFromPreviousRun.Clear();
var bitsForOffset = (byte)fileReader.ReadBits(4);
var bitsForLength = (byte)fileReader.ReadBits(3);
var bytesBuffer = new List <byte> {
Capacity = (int)Math.Pow(2, bitsForOffset) - 1
};
var tokenLengthInBits = bitsForOffset + bitsForLength + 8;
while (!fileReader.ReachedEndOfFile && fileReader.BitsLeft >= tokenLengthInBits)
{
var position = (int)fileReader.ReadBits(bitsForOffset);
var length = (int)fileReader.ReadBits(bitsForLength);
var byteRead = (byte)fileReader.ReadBits(8);
var lz77Token = new Lz77Token
{
Position = position,
Length = length,
Byte = byteRead
};
TokensFromPreviousRun.Add(lz77Token);
var bytes = GetBytesFromBufferBasedOnToken(bytesBuffer, lz77Token);
foreach (var b in bytes)
{
AddByteAndPrintIfBufferIsFull(bytesBuffer, b, fileWriter);
}
AddByteAndPrintIfBufferIsFull(bytesBuffer, lz77Token.Byte, fileWriter);
}
foreach (var byteLeft in bytesBuffer)
{
fileWriter.WriteValueOnBits(byteLeft, 8);
}
}
