public static void StandardFormatToString(string expected, char symbol, byte precision)
{
StandardFormat format = new StandardFormat(symbol, precision);
string actual = format.ToString();
Assert.Equal(expected, actual);
}
//
// Common handler for TryFormat(Double) and TryFormat(Single). You may notice that this particular routine isn't getting into the "no allocation" spirit
// of things. The DoubleToNumber() code is incredibly complex and is one of the few pieces of Number formatting never C#-ized. It would be really
// be preferable not to have another version of that lying around. Until we really hit a scenario where floating point formatting needs the perf, we'll
// make do with this.
//
private static bool TryFormatFloatingPoint <T>(T value, Span <byte> buffer, out int bytesWritten, StandardFormat format) where T : IFormattable
{
if (format.IsDefault)
{
format = 'G';
}
switch (format.Symbol)
{
case 'g':
case 'G':
if (format.Precision != StandardFormat.NoPrecision)
{
throw new NotSupportedException(SR.Argument_GWithPrecisionNotSupported);
}
break;
case 'f':
case 'F':
case 'e':
case 'E':
break;
default:
return(ThrowHelper.TryFormatThrowFormatException(out bytesWritten));
}
string formatString = format.ToString();
string utf16Text = value.ToString(formatString, CultureInfo.InvariantCulture);
int length = utf16Text.Length;
if (length > buffer.Length)
{
bytesWritten = 0;
return(false);
}
for (int i = 0; i < length; i++)
{
Debug.Assert(utf16Text[i] < 128, "A culture-invariant ToString() of a floating point expected to produce ASCII characters only.");
buffer[i] = (byte)(utf16Text[i]);
}
bytesWritten = length;
return(true);
}
public static void StandardFormatToStringOversizedPrecision()
{
// Code coverage: Precision of 100 is not legal but ToString() isn't allowed to throw an exception for that.
// Make sure it doesn't.
const byte BadPrecision = 100;
StandardFormat format = default;
unsafe
{
// We're aiming for the Precision field but we don't know where it is so nuke 'em all.
new Span <byte>(&format, sizeof(StandardFormat)).Fill(BadPrecision);
}
string s = format.ToString();
Assert.NotNull(s);
}