/// <summary>
/// Convert a 64-bit Ryu floating point number to a roundtrip notation string.
/// </summary>
public void ToRoundtripString(StringBuilder result, RyuFormatOptions options,
NumberFormatInfo info = null)
{
// Step 5: Print the decimal representation
if (info == null)
{
info = CultureInfo.CurrentCulture.NumberFormat;
}
if (sign)
{
result.Append(info.NegativeSign);
}
#if DEBUG
if (info.NumberDecimalSeparator.Length > 1)
{
throw new ArgumentException("Requires a single character decimal point");
}
#endif
ulong mantissa = this.mantissa;
uint mantissaShort;
int olength = RyuUtils.DecimalLength17(mantissa), start = result.Length, index =
olength + start;
result.Length = index + 1;
// Print the decimal digits: group of 8
if ((mantissa >> 32) != 0U)
{
// We prefer 32-bit operations, even on 64-bit platforms.
// We have at most 17 digits, and uint can store 9 digits.
// If output doesn't fit into uint, we cut off 8 digits,
// so the rest will fit into uint
ulong q = mantissa / 100000000UL;
mantissaShort = (uint)mantissa - 100000000U * (uint)q;
uint o10000 = mantissaShort / 10000U;
uint c0 = mantissaShort - 10000U * o10000, d0 = o10000 % 10000U;
uint c1 = c0 / 100U, d1 = d0 / 100U;
mantissa = q;
index = result.WriteDigits(index, c0 - 100U * c1);
index = result.WriteDigits(index, c1);
index = result.WriteDigits(index, d0 - 100U * d1);
index = result.WriteDigits(index, d1);
}
mantissaShort = (uint)mantissa;
index = RyuUtils.PrintGroups42(result, ref mantissaShort, index);
// Group of 1
if (mantissaShort >= 10U)
{
string digits = RyuTables.DIGIT_TABLE[mantissaShort];
// We can't use memcpy here: the decimal dot goes between these two digits
result[index--] = digits[1];
result[start] = digits[0];
}
else
{
result[start] = mantissaShort.DigitToChar();
}
// Print decimal point if needed
if (olength > 1)
{
result[start + 1] = info.NumberDecimalSeparator[0];
index += olength;
}
result.Length = index;
RyuUtils.AppendExponent(result, exponent + olength - 1, options, info);
}