/// <summary>Adds the values of two specified <see cref="BigInteger" /> objects.</summary>
/// <returns>The sum of <paramref name="left" /> and <paramref name="right" />.</returns>
/// <param name="left">The first value to add.</param>
/// <param name="right">The second value to add.</param>
public static BigInteger operator +(BigInteger left, BigInteger right)
{
if (right.IsZero)
{
return(left);
}
if (left.IsZero)
{
return(right);
}
var signLeft = 1;
var signRight = 1;
var regLeft = new BigIntegerBuilder(left, ref signLeft);
var regRight = new BigIntegerBuilder(right, ref signRight);
if (signLeft != signRight)
{
regLeft.Sub(ref signLeft, ref regRight);
}
else
{
regLeft.Add(ref regRight);
}
return(regLeft.GetInteger(signLeft));
}
/// <summary>
/// Subtracts a <see cref="BigInteger" /> value from another
/// <see cref="BigInteger" /> value.
/// </summary>
/// <returns>The result of subtracting <paramref name="right" /> from <paramref name="left" />.</returns>
/// <param name="left">The value to subtract from (the minuend).</param>
/// <param name="right">The value to subtract (the subtrahend).</param>
public static BigInteger operator -(BigInteger left, BigInteger right)
{
if (right.IsZero)
{
return(left);
}
if (left.IsZero)
{
return(-right);
}
var leftSign = 1;
var rightSign = -1;
var regLeft = new BigIntegerBuilder(left, ref leftSign);
var regRight = new BigIntegerBuilder(right, ref rightSign);
if (leftSign != rightSign)
{
regLeft.Sub(ref leftSign, ref regRight);
}
else
{
regLeft.Add(ref regRight);
}
return(regLeft.GetInteger(leftSign));
}