/// <summary>
/// This will take a visit from a byte. This will create new code entries as
/// necessary.
/// </summary>
/// <param name="data">The byte to get a visit from.</param>
public void Visit(byte data)
{
buffer.WriteByte(data);
byte[] curBuffer = buffer.ToArray();
LzwNode previous = null;
LzwNode current = this.Root;
bool createNewCode = false;
for (int i = 0; i < curBuffer.Length && current != null; i++)
{
previous = current;
current = current.GetNode(curBuffer[i]);
if (current == null)
{
createNewCode = true;
current = new LzwNode();
previous.SetNode(curBuffer[i], current);
}
}
if (createNewCode)
{
long code = nextCode++;
current.Code = code;
this.Add(code, curBuffer);
buffer = new MemoryStream();
buffer.WriteByte(data);
resetCodeSize();
}
}
public LzwNode GetNode(byte[] data)
{
LzwNode current = this;
for (int i = 0; i < data.Length && current != null; i++)
{
current = current.GetNode(data[i]);
}
return(current);
}
/// <summary>
/// This is the used for the LZWDecode filter. This represents the dictionary mappings
/// between codes and their values.
/// </summary>
/// <remarks>
public LzwDictionary(int size) : base(size)
{
Root = new LzwNode();
for (long i = 0; i < 256; i++)
{
LzwNode node = new LzwNode();
node.Code = i;
this.Root.SetNode((byte)i, node);
this.Add(i, new byte[] { (byte)i });
}
}
public void SetNode(byte b, LzwNode node)
{
subNodes.Add(b, node);
}