public BigInteger Subtract(
BigInteger n)
{
if (n.sign == 0)
return this;
if (this.sign == 0)
return n.Negate();
if (this.sign != n.sign)
return Add(n.Negate());
int compare = CompareNoLeadingZeroes(0, magnitude, 0, n.magnitude);
if (compare == 0)
return Zero;
BigInteger bigun, lilun;
if (compare < 0)
{
bigun = n;
lilun = this;
}
else
{
bigun = this;
lilun = n;
}
return new BigInteger(this.sign * compare, doSubBigLil(bigun.magnitude, lilun.magnitude), true);
}
public BigInteger Add(
BigInteger value)
{
if (this.sign == 0)
return value;
if (this.sign != value.sign)
{
if (value.sign == 0)
return this;
if (value.sign < 0)
return Subtract(value.Negate());
return value.Subtract(Negate());
}
return AddToMagnitude(value.magnitude);
}
public BigInteger ModPow(BigInteger e, BigInteger m)
{
if (m.sign < 1)
throw new ArithmeticException("Modulus must be positive");
if (m.Equals(One))
return Zero;
if (e.sign == 0)
return One;
if (sign == 0)
return Zero;
bool negExp = e.sign < 0;
if (negExp)
e = e.Negate();
BigInteger result = this.Mod(m);
if (!e.Equals(One))
{
if ((m.magnitude[m.magnitude.Length - 1] & 1) == 0)
{
result = ModPowBarrett(result, e, m);
}
else
{
result = ModPowMonty(result, e, m, true);
}
}
if (negExp)
result = result.ModInverse(m);
return result;
}