public void Multiply(Natural factor1, Natural factor2)
{
if (factor1 == Natural.Zero || factor2 == Natural.Zero)
{
factor1.SetValue(Natural.Zero);
}
else if (factor1 == Natural.One)
{
factor1.SetValue(factor2);
}
else
{
Natural increase = factor1.Clone();
Natural decrease = factor2.Clone();
factor1.PushLength(factor1.usedDigits * factor2.usedDigits);
while (decrease > 1) // We already have 1 factor1
{
Natural.Add(factor1, increase);
Natural.Decrement(decrease);
}
factor1.PopLength();
}
}
public void Multiply(Natural factor1, Natural factor2, out Natural product)
{
if (factor1 == Natural.Zero || factor2 == Natural.Zero)
{
product = Natural.Zero;
}
else if (factor1 == Natural.One)
{
product = factor2.Clone();
}
else
{
Natural counter = factor2.Clone();
product = factor1.Clone();
product.PushLength(factor1.usedDigits * factor2.usedDigits);
while (counter > 1) // We already have 1 factor1
{
Natural.Add(product, factor1);
Natural.Decrement(counter);
}
product.PopLength();
}
}
public void Add(Natural x, Natural y)
{
int length = Math.Max(x.usedDigits, y.usedDigits);
x.PushLength(length + 1);
y.PushLength(length); // Expand so we know we can index those digits
Digit carry = 0;
for (int i = 0; i < length; i++)
{
Carry res = (Carry)x.digits[i] + y.digits[i] + carry;
Digit val;
if (res > Digit.MaxValue)
{
carry = 1;
val = (Digit)(res - Digit.MaxValue - 1);
}
else
{
carry = 0;
val = (Digit)res;
}
x.digits[i] = val;
}
x.digits[length] = carry;
x.usedDigits = length + (int)carry; // If carry == 1 we used another extra digit
x.PopLength();
y.PopLength();
}
