/// <summary>
/// Calculates gcd of two numbers using euclidiean algorithm.
/// </summary>
/// <param name="first">First number.</param>
/// <param name="second">Second number.</param>
/// <returns>Returns gcd.</returns>
/// <exception cref="ArgumentException">Thrown if two numbers are 0.</exception>
/// <exception cref="ArgumentOutOfRangeException">Thrown when two numbers
/// are int.MinValue.
/// </exception>
public int Calculate(int first, int second)
{
GcdValidationHelper.CheckNumbers(first, second);
while (second != 0)
{
int temp = first % second;
first = second;
second = temp;
}
return(first);
}
/// <summary>
/// Calculates gcd of two numbers using stein (binary) algorithm.
/// </summary>
/// <param name="first">First number.</param>
/// <param name="second">Second number.</param>
/// <returns>Returns gcd.</returns>
/// <exception cref="ArgumentException">Thrown if two numbers are 0.</exception>
/// <exception cref="ArgumentOutOfRangeException">Thrown when two numbers
/// are int.MinValue.
/// </exception>
public int Calculate(int first, int second)
{
GcdValidationHelper.CheckNumbers(first, second);
int shift;
if (first == 0)
{
return(second);
}
if (second == 0)
{
return(first);
}
uint a = (uint)first;
uint b = (uint)second;
for (shift = 0; ((a | b) & 1) == 0; ++shift)
{
a >>= 1;
b >>= 1;
}
while ((a & 1) == 0)
{
a >>= 1;
}
do
{
while ((b & 1) == 0)
{
b >>= 1;
}
if (a > b)
{
uint t = b;
b = a;
a = t;
}
b = b - a;
}while (b != 0);
return((int)a << shift);
}
