public Int32 GetByteCount()
{
if (mSize != -2)
{
return(mSize);
}
mTree = new Node[T];
mLeaf = new Int32[N_SYM];
InitTree();
BitReaderB R = new BitReaderB(mData, mOffset);
Int32 ct = 0;
Int32 n;
while ((n = GetSymbol(R)) != -1)
{
UpdateNode(n); // this is what makes the coding "Adaptive"
if (n < 256)
{
ct++; // symbol encodes a single byte
}
else
{
ct += n - (256 - 3); // symbol encodes a length
if (GetPosition(R) == -1)
{
return(mSize = -1);
}
}
}
return(mSize = ct);
}
private Int32 GetSymbol(BitReaderB reader)
{
Int32 code = 0, len = 0;
Int32 p = T - 1; // start at root
while (mTree[p].L != -1)
{
Int32 bit = reader.Next(1);
if (bit == -1)
{
return(-1);
}
p = (bit == 0) ? mTree[p].L : mTree[p].R;
code <<= 1;
code += bit;
len++;
}
return(mTree[p].R);
}
private Int32 GetPosition(BitReaderB reader)
{
switch (reader.Next(4))
{
case 0: return(0x000 | reader.Next(5));
case 1: return(0x020 | reader.Next(5));
case 2: return(0x040 | reader.Next(6));
case 3: return(0x080 | reader.Next(6));
case 4: return(0x0c0 | reader.Next(6));
case 5: return(0x100 | reader.Next(7));
case 6: return(0x180 | reader.Next(7));
case 7: return(0x200 | reader.Next(7));
case 8: return(0x280 | reader.Next(7));
case 9: return(0x300 | reader.Next(8));
case 10: return(0x400 | reader.Next(8));
case 11: return(0x500 | reader.Next(8));
case 12: return(0x600 | reader.Next(9));
case 13: return(0x800 | reader.Next(9));
case 14: return(0xa00 | reader.Next(9));
case 15: return(0xc00 | reader.Next(10));
}
return(-1);
}
public Byte[] GetBytes()
{
Int32 q = GetByteCount();
if (q == -1)
{
return(null);
}
Byte[] data = new Byte[q];
q = 0;
Byte[] buf = new Byte[N];
Int32 p = N - F;
for (Int32 i = 0; i < p; i++)
{
buf[i] = 32;
}
InitTree();
BitReaderB R = new BitReaderB(mData, mOffset);
Int32 n;
while ((n = GetSymbol(R)) != -1)
{
UpdateNode(n); // this is what makes the coding "Adaptive"
if (n < 256)
{
data[q++] = (Byte)n; // symbol encodes a single byte
buf[p++] = (Byte)n;
if (p >= buf.Length)
{
p = 0;
}
}
else
{
n -= (256 - 3); // symbol encodes a length
Int32 m = GetPosition(R); // (position follows)
Int32 k = p - 1 - m;
if (k < 0)
{
k += buf.Length;
}
for (Int32 i = 0; i < n; i++)
{
data[q++] = buf[k];
buf[p++] = buf[k++];
if (p >= buf.Length)
{
p = 0;
}
if (k >= buf.Length)
{
k = 0;
}
}
}
}
return(data);
}
