internal static void Decode(BitReservoir br, int table, out float x, out float y, out float v, out float w)
{
var val = DecodeSymbol(br, table);
v = w = x = y = 0;
if ((val & 0x8) != 0)
{
if (br.Get1Bit() == 1)
{
v = -_floatLookup[1];
}
else
{
v = _floatLookup[1];
}
}
if ((val & 0x4) != 0)
{
if (br.Get1Bit() == 1)
{
w = -_floatLookup[1];
}
else
{
w = _floatLookup[1];
}
}
if ((val & 0x2) != 0)
{
if (br.Get1Bit() == 1)
{
x = -_floatLookup[1];
}
else
{
x = _floatLookup[1];
}
}
if ((val & 0x1) != 0)
{
if (br.Get1Bit() == 1)
{
y = -_floatLookup[1];
}
else
{
y = _floatLookup[1];
}
}
}
// In C#, bit operations are faster than the tree traversal the spec is written for.
static byte DecodeSymbol(BitReservoir br, int table)
{
// get the huffman node for decoding
int maxBits;
var node = GetNode(table, out maxBits);
// get some bits to work with
int readBits;
int bits = br.TryPeekBits(maxBits, out readBits);
if (readBits < maxBits)
{
bits <<= maxBits - readBits;
}
// try to find the correct node
while (node != null && node.Length <= readBits)
{
if ((bits & node.Mask) == node.Bits)
{
// found it! Advance the read counter
br.SkipBits(node.Length);
break;
}
node = node.Next;
}
// apply the value
if (node != null && node.Length <= readBits)
{
return node.Value;
}
else
{
// should we advance the reader???? need to check the spec
return 0;
}
}
internal static void Decode(BitReservoir br, int table, out float x, out float y)
{
if (table == 0 || table == 4 || table == 14)
{
x = y = 0;
}
else
{
var val = DecodeSymbol(br, table);
var ix = val >> 4;
var iy = val & 15;
int linBits = LIN_BITS[table];
if (linBits > 0 && ix == 15) ix += br.GetBits(linBits);
if (ix != 0 && br.Get1Bit() != 0)
{
x = -_floatLookup[ix];
}
else
{
x = _floatLookup[ix];
}
if (linBits > 0 && iy == 15) iy += br.GetBits(linBits);
if (iy != 0 && br.Get1Bit() != 0)
{
y = -_floatLookup[iy];
}
else
{
y = _floatLookup[iy];
}
}
}