/// <summary>
/// Reduces this GF2nPolynomialElement modulo the field-polynomial
/// </summary>
private void ReduceThis()
{
if (polynomial.Length > mDegree)
{ // really reduce ?
if (((GF2nPolynomialField)mField).IsTrinomial)
{ // fieldpolonomial
// is trinomial
int tc;
try
{
tc = ((GF2nPolynomialField)mField).Tc;
}
catch (Exception NATExc)
{
throw new Exception("GF2nPolynomialElement.Reduce: the field polynomial is not a trinomial!");
}
// do we have to use slow bitwise reduction ?
if (((mDegree - tc) <= 32) || (polynomial.Length > (mDegree << 1)))
{
ReduceTrinomialBitwise(tc);
return;
}
polynomial.ReduceTrinomial(mDegree, tc);
return;
}
else if (((GF2nPolynomialField)mField).IsPentanomial) // fieldpolynomial is pentanomial
{
int[] pc;
try
{
pc = ((GF2nPolynomialField)mField).Pc;
}
catch (Exception NATExc)
{
throw new Exception("GF2nPolynomialElement.Reduce: the field polynomial is not a pentanomial!");
}
// do we have to use slow bitwise reduction ?
if (((mDegree - pc[2]) <= 32) || (polynomial.Length > (mDegree << 1)))
{
ReducePentanomialBitwise(pc);
return;
}
polynomial.ReducePentanomial(mDegree, pc);
return;
}
else
{ // fieldpolynomial is something else
polynomial = polynomial.Remainder(mField.FieldPolynomial);
polynomial.ExpandN(mDegree);
return;
}
}
if (polynomial.Length < mDegree)
{
polynomial.ExpandN(mDegree);
}
}