private static bool TryFormatInt64N(long value, byte precision, Span <byte> buffer, out int bytesWritten)
{
int digitCount = FormattingHelpers.CountDigits(value);
int groupSeparators = (int)FormattingHelpers.DivMod(digitCount, Utf8Constants.GroupSize, out long firstGroup);
if (firstGroup == 0)
{
firstGroup = 3;
groupSeparators--;
}
int trailingZeros = (precision == StandardFormat.NoPrecision) ? 2 : precision;
int idx = (int)((value >> 63) & 1) + digitCount + groupSeparators;
bytesWritten = idx;
if (trailingZeros > 0)
{
bytesWritten += trailingZeros + 1; // +1 for period.
}
if (buffer.Length < bytesWritten)
{
bytesWritten = 0;
return(false);
}
ref byte utf8Bytes = ref MemoryMarshal.GetReference(buffer);
private static bool TryFormatUInt64D(ulong value, byte precision, Span <byte> buffer, out int bytesWritten)
{
if (value <= long.MaxValue)
{
return(TryFormatInt64D((long)value, precision, buffer, out bytesWritten));
}
// Remove a single digit from the number. This will get it below long.MaxValue
// Then we call the faster long version and follow-up with writing the last
// digit. This ends up being faster by a factor of 2 than to just do the entire
// operation using the unsigned versions.
value = FormattingHelpers.DivMod(value, 10, out ulong lastDigit);
if (precision != StandardFormat.NoPrecision && precision > 0)
{
precision -= 1;
}
if (!TryFormatInt64D((long)value, precision, buffer, out bytesWritten))
{
return(false);
}
if (buffer.Length - 1 < bytesWritten)
{
bytesWritten = 0;
return(false);
}
ref byte utf8Bytes = ref buffer.DangerousGetPinnableReference();
private static bool TryFormatUInt64N(ulong value, byte precision, Span <byte> buffer, out int bytesWritten)
{
if (value <= long.MaxValue)
{
return(TryFormatInt64N((long)value, precision, buffer, out bytesWritten));
}
// The ulong path is much slower than the long path here, so we are doing the last group
// inside this method plus the zero padding but routing to the long version for the rest.
value = FormattingHelpers.DivMod(value, 1000, out ulong lastGroup);
if (!TryFormatInt64N((long)value, 0, buffer, out bytesWritten))
{
return(false);
}
if (precision == StandardFormat.NoPrecision)
{
precision = 2;
}
int idx = bytesWritten;
// Since this method routes entirely to the long version if the number is smaller than
// long.MaxValue, we are guaranteed to need to write 3 more digits here before the set
// of trailing zeros.
bytesWritten += 4; // 3 digits + group separator
if (precision > 0)
{
bytesWritten += precision + 1; // +1 for period.
}
if (buffer.Length < bytesWritten)
{
bytesWritten = 0;
return(false);
}
ref byte utf8Bytes = ref buffer.DangerousGetPinnableReference();
/// <summary>
/// Formats a TimeSpan as a UTF8 string.
/// </summary>
/// <param name="value">Value to format</param>
/// <param name="buffer">Buffer to write the UTF8-formatted value to</param>
/// <param name="bytesWritten">Receives the length of the formatted text in bytes</param>
/// <param name="format">The standard format to use</param>
/// <returns>
/// true for success. "bytesWritten" contains the length of the formatted text in bytes.
/// false if buffer was too short. Iteratively increase the size of the buffer and retry until it succeeds.
/// </returns>
/// <remarks>
/// Formats supported:
/// c/t/T (default) [-][d.]hh:mm:ss[.fffffff] (constant format)
/// G [-]d:hh:mm:ss.fffffff (general long)
/// g [-][d:]h:mm:ss[.f[f[f[f[f[f[f[]]]]]]] (general short)
/// </remarks>
/// <exceptions>
/// <cref>System.FormatException</cref> if the format is not valid for this data type.
/// </exceptions>
public static bool TryFormat(TimeSpan value, Span <byte> buffer, out int bytesWritten, StandardFormat format = default)
{
char symbol = format.IsDefault ? 'c' : format.Symbol;
switch (symbol)
{
case 'G':
case 'g':
case 'c':
case 't':
case 'T':
{
bool longForm = (symbol == 'G');
bool constant = (symbol == 't' || symbol == 'T' || symbol == 'c');
long ticks = value.Ticks;
int days = (int)FormattingHelpers.DivMod(ticks, TimeSpan.TicksPerDay, out long timeLeft);
bool showSign = false;
if (ticks < 0)
{
showSign = true;
days = -days;
timeLeft = -timeLeft;
}
int hours = (int)FormattingHelpers.DivMod(timeLeft, TimeSpan.TicksPerHour, out timeLeft);
int minutes = (int)FormattingHelpers.DivMod(timeLeft, TimeSpan.TicksPerMinute, out timeLeft);
int seconds = (int)FormattingHelpers.DivMod(timeLeft, TimeSpan.TicksPerSecond, out long fraction);
int dayDigits = 0;
int hourDigits = (constant || longForm || hours > 9) ? 2 : 1;
int fractionDigits = 0;
bytesWritten = hourDigits + 6; // [h]h:mm:ss
if (showSign)
{
bytesWritten += 1; // [-]
}
if (longForm || days > 0)
{
dayDigits = FormattingHelpers.CountDigits(days);
bytesWritten += dayDigits + 1; // [d'.']
}
if (longForm || fraction > 0)
{
fractionDigits = (longForm || constant) ? Utf8Constants.DateTimeNumFractionDigits : FormattingHelpers.CountFractionDigits(fraction);
bytesWritten += fractionDigits + 1; // ['.'fffffff] or ['.'FFFFFFF] for short-form
}
if (buffer.Length < bytesWritten)
{
bytesWritten = 0;
return(false);
}
ref byte utf8Bytes = ref buffer.DangerousGetPinnableReference();
int idx = 0;
if (showSign)
{
Unsafe.Add(ref utf8Bytes, idx++) = Utf8Constants.Minus;
}
if (dayDigits > 0)
{
idx += FormattingHelpers.WriteDigits(days, dayDigits, ref utf8Bytes, idx);
Unsafe.Add(ref utf8Bytes, idx++) = constant ? Utf8Constants.Period : Utf8Constants.Colon;
}
idx += FormattingHelpers.WriteDigits(hours, hourDigits, ref utf8Bytes, idx);
Unsafe.Add(ref utf8Bytes, idx++) = Utf8Constants.Colon;
idx += FormattingHelpers.WriteDigits(minutes, 2, ref utf8Bytes, idx);
Unsafe.Add(ref utf8Bytes, idx++) = Utf8Constants.Colon;
idx += FormattingHelpers.WriteDigits(seconds, 2, ref utf8Bytes, idx);
if (fractionDigits > 0)
{
Unsafe.Add(ref utf8Bytes, idx++) = Utf8Constants.Period;
idx += FormattingHelpers.WriteFractionDigits(fraction, fractionDigits, ref utf8Bytes, idx);
}
return(true);
}
/// <summary>
/// Formats a TimeSpan as a UTF8 string.
/// </summary>
/// <param name="value">Value to format</param>
/// <param name="destination">Buffer to write the UTF8-formatted value to</param>
/// <param name="bytesWritten">Receives the length of the formatted text in bytes</param>
/// <param name="format">The standard format to use</param>
/// <returns>
/// true for success. "bytesWritten" contains the length of the formatted text in bytes.
/// false if buffer was too short. Iteratively increase the size of the buffer and retry until it succeeds.
/// </returns>
/// <remarks>
/// Formats supported:
/// c/t/T (default) [-][d.]hh:mm:ss[.fffffff] (constant format)
/// G [-]d:hh:mm:ss.fffffff (general long)
/// g [-][d:][h]h:mm:ss[.f[f[f[f[f[f[f]]]]]] (general short)
/// </remarks>
/// <exceptions>
/// <cref>System.FormatException</cref> if the format is not valid for this data type.
/// </exceptions>
public static bool TryFormat(TimeSpan value, Span <byte> destination, out int bytesWritten, StandardFormat format = default)
{
char symbol = FormattingHelpers.GetSymbolOrDefault(format, 'c');
switch (symbol)
{
case 'c':
case 'G':
case 'g':
break;
case 't':
case 'T':
symbol = 'c';
break;
default:
return(FormattingHelpers.TryFormatThrowFormatException(out bytesWritten));
}
// First, calculate how large an output buffer is needed to hold the entire output.
int requiredOutputLength = 8; // start with "hh:mm:ss" and adjust as necessary
uint fraction;
ulong totalSecondsRemaining;
{
// Turn this into a non-negative TimeSpan if possible.
var ticks = value.Ticks;
if (ticks < 0)
{
ticks = -ticks;
if (ticks < 0)
{
Debug.Assert(ticks == long.MinValue /* -9223372036854775808 */);
// We computed these ahead of time; they're straight from the decimal representation of Int64.MinValue.
fraction = 4775808;
totalSecondsRemaining = 922337203685;
goto AfterComputeFraction;
}
}
totalSecondsRemaining = FormattingHelpers.DivMod((ulong)Math.Abs(value.Ticks), TimeSpan.TicksPerSecond, out ulong fraction64);
fraction = (uint)fraction64;
}
AfterComputeFraction:
int fractionDigits = 0;
if (symbol == 'c')
{
// Only write out the fraction if it's non-zero, and in that
// case write out the entire fraction (all digits).
if (fraction != 0)
{
fractionDigits = Utf8Constants.DateTimeNumFractionDigits;
}
}
else if (symbol == 'G')
{
// Always write out the fraction, even if it's zero.
fractionDigits = Utf8Constants.DateTimeNumFractionDigits;
}
else
{
// Only write out the fraction if it's non-zero, and in that
// case write out only the most significant digits.
if (fraction != 0)
{
fractionDigits = Utf8Constants.DateTimeNumFractionDigits - FormattingHelpers.CountDecimalTrailingZeros(fraction, out fraction);
}
}
Debug.Assert(fraction < 10_000_000);
// If we're going to write out a fraction, also need to write the leading decimal.
if (fractionDigits != 0)
{
requiredOutputLength += fractionDigits + 1;
}
ulong totalMinutesRemaining = 0;
ulong seconds = 0;
if (totalSecondsRemaining > 0)
{
// Only compute minutes if the TimeSpan has an absolute value of >= 1 minute.
totalMinutesRemaining = FormattingHelpers.DivMod(totalSecondsRemaining, 60 /* seconds per minute */, out seconds);
}
Debug.Assert(seconds < 60);
ulong totalHoursRemaining = 0;
ulong minutes = 0;
if (totalMinutesRemaining > 0)
{
// Only compute hours if the TimeSpan has an absolute value of >= 1 hour.
totalHoursRemaining = FormattingHelpers.DivMod(totalMinutesRemaining, 60 /* minutes per hour */, out minutes);
}
Debug.Assert(minutes < 60);
// At this point, we can switch over to 32-bit divmod since the data has shrunk far enough.
Debug.Assert(totalHoursRemaining <= uint.MaxValue);
uint days = 0;
uint hours = 0;
if (totalHoursRemaining > 0)
{
// Only compute days if the TimeSpan has an absolute value of >= 1 day.
days = FormattingHelpers.DivMod((uint)totalHoursRemaining, 24 /* hours per day */, out hours);
}
Debug.Assert(hours < 24);
int hourDigits = 2;
if (hours < 10 && symbol == 'g')
{
// Only writing a one-digit hour, not a two-digit hour
hourDigits--;
requiredOutputLength--;
}
int dayDigits = 0;
if (days == 0)
{
if (symbol == 'G')
{
requiredOutputLength += 2; // for the leading "0:"
dayDigits = 1;
}
}
else
{
dayDigits = FormattingHelpers.CountDigits(days);
requiredOutputLength += dayDigits + 1; // for the leading "d:" (or "d.")
}
if (value.Ticks < 0)
{
requiredOutputLength++; // for the leading '-' sign
}
if (destination.Length < requiredOutputLength)
{
bytesWritten = 0;
return(false);
}
bytesWritten = requiredOutputLength;
int idx = 0;
// Write leading '-' if necessary
if (value.Ticks < 0)
{
destination[idx++] = Utf8Constants.Minus;
}
// Write day (and separator) if necessary
if (dayDigits > 0)
{
FormattingHelpers.WriteDigits(days, destination.Slice(idx, dayDigits));
idx += dayDigits;
destination[idx++] = (symbol == 'c') ? Utf8Constants.Period : Utf8Constants.Colon;
}
// Write "[h]h:mm:ss"
FormattingHelpers.WriteDigits(hours, destination.Slice(idx, hourDigits));
idx += hourDigits;
destination[idx++] = Utf8Constants.Colon;
FormattingHelpers.WriteDigits((uint)minutes, destination.Slice(idx, 2));
idx += 2;
destination[idx++] = Utf8Constants.Colon;
FormattingHelpers.WriteDigits((uint)seconds, destination.Slice(idx, 2));
idx += 2;
// Write fraction (and separator) if necessary
if (fractionDigits > 0)
{
destination[idx++] = Utf8Constants.Period;
FormattingHelpers.WriteDigits(fraction, destination.Slice(idx, fractionDigits));
idx += fractionDigits;
}
// And we're done!
Debug.Assert(idx == requiredOutputLength);
return(true);
}
