/// <summary>
/// Rounds the given non-negative value to the "nearest" integer. Nearest is
/// determined by the rounding method specified. Rounding methods are defined
/// in <seealso cref="BigDecimal"/>.
/// </summary>
/// <param name="unscaled"> Value to round. </param>
/// <param name="sign"> Sign of the original, scaled value. </param>
/// <param name="roundingMethod"> Rounding method, as defined in <seealso cref="BigDecimal"/>. </param>
/// <returns> the rounded value. </returns>
/// <exception cref="MathArithmeticException"> if an exact operation is required but result is not exact </exception>
/// <exception cref="MathIllegalArgumentException"> if {@code roundingMethod} is not a valid rounding method.
/// @since 1.1 (previously in {@code MathUtils}, moved as of version 3.0) </exception>
private static double RoundUnscaled(double unscaled, double sign, int roundingMethod)
{
switch (roundingMethod)
{
case decimal.ROUND_CEILING:
if (sign == -1)
{
unscaled = FastMath.Floor(FastMath.nextAfter(unscaled, double.NegativeInfinity));
}
else
{
unscaled = FastMath.Ceil(FastMath.nextAfter(unscaled, double.PositiveInfinity));
}
break;
case decimal.ROUND_DOWN:
unscaled = FastMath.Floor(FastMath.nextAfter(unscaled, double.NegativeInfinity));
break;
case decimal.ROUND_FLOOR:
if (sign == -1)
{
unscaled = FastMath.Ceil(FastMath.nextAfter(unscaled, double.PositiveInfinity));
}
else
{
unscaled = FastMath.Floor(FastMath.nextAfter(unscaled, double.NegativeInfinity));
}
break;
case decimal.ROUND_HALF_DOWN:
{
unscaled = FastMath.nextAfter(unscaled, double.NegativeInfinity);
double fraction = unscaled - FastMath.Floor(unscaled);
if (fraction > 0.5)
{
unscaled = FastMath.Ceil(unscaled);
}
else
{
unscaled = FastMath.Floor(unscaled);
}
break;
}
case decimal.ROUND_HALF_EVEN:
{
double fraction = unscaled - FastMath.Floor(unscaled);
if (fraction > 0.5)
{
unscaled = FastMath.Ceil(unscaled);
}
else if (fraction < 0.5)
{
unscaled = FastMath.Floor(unscaled);
}
else
{
// The following equality test is intentional and needed for rounding purposes
if (FastMath.Floor(unscaled) / 2.0 == FastMath.Floor(FastMath.Floor(unscaled) / 2.0))
{ // even
unscaled = FastMath.Floor(unscaled);
}
else
{ // odd
unscaled = FastMath.Ceil(unscaled);
}
}
break;
}
case decimal.ROUND_HALF_UP:
{
unscaled = FastMath.nextAfter(unscaled, double.PositiveInfinity);
double fraction = unscaled - FastMath.Floor(unscaled);
if (fraction >= 0.5)
{
unscaled = FastMath.Ceil(unscaled);
}
else
{
unscaled = FastMath.Floor(unscaled);
}
break;
}
case decimal.ROUND_UNNECESSARY:
if (unscaled != FastMath.Floor(unscaled))
{
throw new MathArithmeticException();
}
break;
case decimal.ROUND_UP:
// do not round if the discarded fraction is equal to zero
if (unscaled != FastMath.Floor(unscaled))
{
unscaled = FastMath.Ceil(FastMath.nextAfter(unscaled, double.PositiveInfinity));
}
break;
default:
throw new MathIllegalArgumentException(LocalizedFormats.INVALID_ROUNDING_METHOD, roundingMethod, "ROUND_CEILING", decimal.ROUND_CEILING, "ROUND_DOWN", decimal.ROUND_DOWN, "ROUND_FLOOR", decimal.ROUND_FLOOR, "ROUND_HALF_DOWN", decimal.ROUND_HALF_DOWN, "ROUND_HALF_EVEN", decimal.ROUND_HALF_EVEN, "ROUND_HALF_UP", decimal.ROUND_HALF_UP, "ROUND_UNNECESSARY", decimal.ROUND_UNNECESSARY, "ROUND_UP", decimal.ROUND_UP);
}
return(unscaled);
}
