public static bool Decompress(Stream input, Stream output)
{
if (!input.CanRead || !output.CanWrite)
{
return false;
}
BinaryReader reader = new BinaryReader(input);
int header = reader.ReadInt32();
if ((header & 0xFF) != 0x10)
{
return false;
}
var slidingWindow = new LinkedList<byte>();
//var slidingWindow = new LinkedArrayList<byte>(); doesn't work
int decompSize = header >> 8;
long startPosition = output.Position;
while ((output.Position - startPosition) < decompSize)
{
if (input.Position >= input.Length)
return false;
byte flags = reader.ReadByte();
for (int i = 0; i < BlockSize; i++)
{
if ((flags & (0x80 >> i)) != 0)
{
if (input.Position >= input.Length - 1)
return false;
byte first = reader.ReadByte();
byte second = reader.ReadByte();
int position = (((first << 8) + second + 1) & 0xFFF);
int amountToCopy = (3 + ((first >> 4) & 0xF));
if (position > (output.Position - startPosition))
return false;
byte[] dataToCopy =
slidingWindow
.EnumerateLast(position)
.Repeat()
.Take(amountToCopy)
.ToArray();
output.Write(dataToCopy, 0, dataToCopy.Length);
for (int slidingI = 0; slidingI < dataToCopy.Length; slidingI++)
{
slidingWindow.AddLast(dataToCopy[slidingI]);
}
slidingWindow.RemoveExtra(SlidingWindowSize);
}
else
{
if (input.Position > input.Length)
return false;
byte raw = reader.ReadByte();
slidingWindow.AddLast(raw);
slidingWindow.RemoveExtra(SlidingWindowSize);
output.WriteByte(raw);
}
if ((output.Position - startPosition) >= decompSize)
break;
}
}
slidingWindow.Clear();
return true;
}
