public byte[] Decode(Stream stream)
{
using (var ms = new MemoryStream())
{
var br = new BitReader(stream);
int value;
int i = 0;
int prevValue = -1;
byte lastChar = 0;
if (br.BitsRead + lookup.CodeLen <= br.BitsLength)
{
value = br.ReadBits(lookup.CodeLen);
lastChar = lookup.OutputText(lastChar, value, ms);
prevValue = value;
}
while (br.BitsRead < br.BitsLength)
{
if (lookup.Count >= 0xFFF)
{
lookup.Reset();
if (br.BitsRead + lookup.CodeLen <= br.BitsLength)
{
value = br.ReadBits(lookup.CodeLen);
lastChar = lookup.OutputText(lastChar, value, ms);
prevValue = value;
}
}
if (br.BitsRead + lookup.CodeLen <= br.BitsLength)
{
lookup.EnsureCodeLen();
value = br.ReadBits(lookup.CodeLen);
}
else
{
break;
}
if (value != lookup.Count)
{
lastChar = lookup.OutputText(lastChar, value, ms);
lookup.AppendChar(lastChar, prevValue);
}
else
{
lookup.AppendChar(lastChar, prevValue);
lastChar = lookup.OutputText(lastChar, value, ms);
}
prevValue = value;
}
return(ms.ToArray());
}
}
public byte[] Encode(byte[] input)
{
var buffer = new byte[0xffff];
var bufferIdx = 0;
using (var ms = new MemoryStream())
{
using (var bw = new BitWriter(ms))
{
int i = 0;
string w = "";
while (i < input.Length)
{
bufferIdx = 0;
buffer[bufferIdx++] = input[i++];
int cur = -1, prev = -1;
while ((cur = lookup.FindEntry(buffer, 0, bufferIdx)) != -1 && i < input.Length)
{
buffer[bufferIdx++] = input[i++];
prev = cur;
}
if (cur == -1)
{
//Debug.WriteLine("E: " + prev);
bw.WriteBits((uint)prev, (uint)lookup.CodeLen);
lookup.AppendChar(buffer[bufferIdx - 1], prev);
i--;
}
else
{
//Debug.WriteLine("E: " + cur);
bw.WriteBits((uint)cur, (uint)lookup.CodeLen);
}
lookup.EnsureCodeLen2();
if (lookup.Count > 0xFFF)
{
lookup.Reset();
}
}
}
return(ms.ToArray());
}
}
