/// <summary>
/// Calculates 'this' mod n2 (using the schoolbook division algorithm as above)
/// </summary>
/// <param name="n2"></param>
public void Mod(BigInt n2)
{
if (n2.digitArray.Length != digitArray.Length) MakeSafe(ref n2);
int OldLength = digitArray.Length;
//First, we need to prepare the operands for division using Div_32, which requires
//That the most significant digit of n2 be set. To do this, we need to shift n2 (and therefore n1) up.
//This operation can potentially increase the precision of the operands.
int shift = MakeSafeDiv(this, n2);
BigInt Q = new BigInt(this.pres);
BigInt R = new BigInt(this.pres);
Q.digitArray = new UInt32[this.digitArray.Length];
R.digitArray = new UInt32[this.digitArray.Length];
Div_32(this, n2, Q, R);
//Restore n2 to its pre-shift value
n2.RSH(shift);
R.RSH(shift);
R.sign = (sign != n2.sign);
AssignInt(R);
//Reset the lengths of the operands
SetNumDigits(OldLength);
n2.SetNumDigits(OldLength);
}
/// <summary>
/// Calculates 'this'^power
/// </summary>
/// <param name="power"></param>
public void Power(BigInt power)
{
if (power.IsZero() || power.sign)
{
Zero();
digitArray[0] = 1;
return;
}
BigInt pow = new BigInt(power);
BigInt temp = new BigInt(this);
BigInt powTerm = new BigInt(this);
pow.Decrement();
for (; !pow.IsZero(); pow.RSH(1))
{
if ((pow.digitArray[0] & 1) == 1)
{
temp.Mul(powTerm);
}
powTerm.Square();
}
Assign(temp);
}
/// <summary>
/// The right-shift operator
/// </summary>
public static BigInt operator >>(BigInt n1, int n2)
{
BigInt res = new BigInt(n1);
res.RSH(n2);
return res;
}