private static Int64 DoubleRoundToCents(double input, ParsingScale scale)
{
double epsilonLimit = 0.004;
double scalingFactor = 100.0;
if (scale == ParsingScale.Metacents) // factor 10,000 instead of 100
{
epsilonLimit /= 100.0;
scalingFactor *= 100.0;
}
// Epsilon and true-zero values
if (input > -epsilonLimit && input < epsilonLimit)
{
return(0);
}
// Positive values
if (input > 0.0)
{
return(Convert.ToInt64(input * scalingFactor + 0.2)); // +0.2 avoids rounding errors from epsilon losses of precision
}
// Negative values
return(Convert.ToInt64(input * scalingFactor - 0.2)); // -0.2 avoids rounding errors from epsilon losses of precision
}
public static Int64 ParseDoubleStringAsCents(string input, CultureInfo culture = null, ParsingScale scale = ParsingScale.Cents)
{
// Parses first according to culture, and if fails, according to neutral culture
// Throws ArgumentException if fails
double outputHolder;
bool success = false;
input = input.Trim();
if (culture == null)
{
culture = CultureInfo.CurrentCulture;
}
// Try current or provided culture first
success = Double.TryParse(input,
NumberStyles.AllowThousands | NumberStyles.AllowLeadingSign | NumberStyles.AllowDecimalPoint,
culture, out outputHolder);
if (success)
{
return(DoubleRoundToCents(outputHolder, scale));
}
// Try invariant (US) culture as fallback
success = Double.TryParse(input,
NumberStyles.AllowThousands | NumberStyles.AllowLeadingSign | NumberStyles.AllowDecimalPoint,
CultureInfo.InvariantCulture, out outputHolder);
if (success)
{
return(DoubleRoundToCents(outputHolder, scale));
}
// No joy, could not convert, so throw
throw new ArgumentException("Could not parse input as cents: " + input);
}
