Function DecimalToHLC

pkg/sql/sem/tree/as_of.go:138–169

DecimalToHLC performs the conversion from an inputted DECIMAL datum for an AS OF SYSTEM TIME query to an HLC timestamp.

(d *apd.Decimal)

// DecimalToHLC performs the conversion from an inputted DECIMAL datum for an
// AS OF SYSTEM TIME query to an HLC timestamp.
func DecimalToHLC(d *apd.Decimal) (hlc.Timestamp, error) {
	// Format the decimal into a string and split on `.` to extract the nanosecond
	// walltime and logical tick parts.
	// TODO(mjibson): use d.Modf() instead of converting to a string.
	s := d.Text('f')
	parts := strings.SplitN(s, ".", 2)
	nanos, err := strconv.ParseInt(parts[0], 10, 64)
	if err != nil {
		return hlc.Timestamp{}, pgerror.Wrapf(err, pgcode.Syntax, "parsing argument")
	}
	var logical int64
	if len(parts) > 1 {
		// logicalLength is the number of decimal digits expected in the
		// logical part to the right of the decimal. See the implementation of
		// cluster_logical_timestamp().
		const logicalLength = 10
		p := parts[1]
		if lp := len(p); lp > logicalLength {
			return hlc.Timestamp{}, pgerror.Newf(pgcode.Syntax, "logical part has too many digits")
		} else if lp < logicalLength {
			p += strings.Repeat("0", logicalLength-lp)
		}
		logical, err = strconv.ParseInt(p, 10, 32)
		if err != nil {
			return hlc.Timestamp{}, pgerror.Wrapf(err, pgcode.Syntax, "parsing argument")
		}
	}
	return hlc.Timestamp{
		WallTime: nanos,
		Logical:  int32(logical),
	}, nil
}