Пример #1
0
        /// <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);
        }
Пример #2
0
        /// <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);
        }
Пример #3
0
 /// <summary>
 /// The right-shift operator
 /// </summary>
 public static BigInt operator >>(BigInt n1, int n2)
 {
     BigInt res = new BigInt(n1);
     res.RSH(n2);
     return res;
 }