private unsafe string Convert(double d)
{
var buffer = stackalloc char[24];
var len = FastDtoa.Convert(d, buffer);
return(new string(buffer, 0, len));
}
public static string ToNumberString(double m)
{
if (double.IsNaN(m))
{
return("NaN");
}
if (m.Equals(0))
{
return("0");
}
if (double.IsPositiveInfinity(m) || m >= double.MaxValue)
{
return("Infinity");
}
if (m < 0)
{
return("-" + ToNumberString(-m));
}
// V8 FastDtoa can't convert all numbers, so try it first but
// fall back to old DToA in case it fails
var result = FastDtoa.NumberToString(m);
if (result != null)
{
return(result);
}
// s is all digits (significand)
// k number of digits of s
// n total of digits in fraction s*10^n-k=m
// 123.4 s=1234, k=4, n=3
// 1234000 s = 1234, k=4, n=7
string s = null;
var rFormat = m.ToString("r");
if (rFormat.IndexOf("e", StringComparison.OrdinalIgnoreCase) == -1)
{
s = rFormat.Replace(".", "").TrimStart('0').TrimEnd('0');
}
const string format = "0.00000000000000000e0";
var parts = m.ToString(format, CultureInfo.InvariantCulture).Split('e');
if (s == null)
{
s = parts[0].TrimEnd('0').Replace(".", "");
}
var n = int.Parse(parts[1]) + 1;
var k = s.Length;
if (k <= n && n <= 21)
{
return(s + new string('0', n - k));
}
if (0 < n && n <= 21)
{
return(s.Substring(0, n) + '.' + s.Substring(n));
}
if (-6 < n && n <= 0)
{
return("0." + new string('0', -n) + s);
}
if (k == 1)
{
return(s + "e" + (n - 1 < 0 ? "-" : "+") + System.Math.Abs(n - 1));
}
return(s.Substring(0, 1) + "." + s.Substring(1) + "e" + (n - 1 < 0 ? "-" : "+") + System.Math.Abs(n - 1));
}
