private byte[] DoLZWDecode(Bytes.Buffer input, int earlyChange)
{
List <byte[]> codeTable = new List <byte[]>();
int chunk = 9;
var decoded = new Bytes.Buffer();
long nextCommand;
long prevCommand = -1;
try
{
while ((nextCommand = input.ReadBits(chunk)) != EOD)
{
if (nextCommand == CLEAR_TABLE)
{
chunk = 9;
codeTable = CreateCodeTable();
prevCommand = -1;
}
else
{
if (nextCommand < codeTable.Count)
{
byte[] data = codeTable[(int)nextCommand];
byte firstByte = data[0];
decoded.Write(data);
if (prevCommand != -1)
{
CheckIndexBounds(codeTable, prevCommand, input);
data = codeTable[(int)prevCommand];
byte[] newData = data.CopyOf(data.Length + 1);
newData[data.Length] = firstByte;
codeTable.Add(newData);
}
}
else
{
CheckIndexBounds(codeTable, prevCommand, input);
byte[] data = codeTable[(int)prevCommand];
byte[] newData = data.CopyOf(data.Length + 1);
newData[data.Length] = data[0];
decoded.Write(newData);
codeTable.Add(newData);
}
chunk = CalculateChunk(codeTable.Count, earlyChange);
prevCommand = nextCommand;
}
}
}
catch (Exception ex)
{
Debug.WriteLine("warn: Premature EOF input LZW stream, EOD code missing " + ex);
}
return(decoded.GetBuffer());
}