Function DecodeIntoNonsortingDecimal

postgres/parser/encoding/decimal.go:640–691

DecodeIntoNonsortingDecimal is like DecodeNonsortingDecimal, but it operates on the passed-in *apd.Decimal instead of producing a new one.

(dec *apd.Decimal, buf []byte, tmp []byte)

// DecodeIntoNonsortingDecimal is like DecodeNonsortingDecimal, but it operates
// on the passed-in *apd.Decimal instead of producing a new one.
func DecodeIntoNonsortingDecimal(dec *apd.Decimal, buf []byte, tmp []byte) error {
	*dec = apd.Decimal{}
	switch buf[0] {
	case decimalNaN:
		dec.Form = apd.NaN
		return nil
	case decimalNegativeInfinity:
		dec.Form = apd.Infinite
		dec.Negative = true
		return nil
	case decimalInfinity:
		dec.Form = apd.Infinite
		return nil
	case decimalZero:
		return nil
	}

	dec.Form = apd.Finite
	switch {
	case buf[0] == decimalNegLarge:
		if err := decodeNonsortingDecimalValue(dec, false, buf[1:], tmp); err != nil {
			return err
		}
		dec.Negative = true
		return nil
	case buf[0] == decimalNegMedium:
		decodeNonsortingDecimalValueWithoutExp(dec, buf[1:], tmp)
		dec.Negative = true
		return nil
	case buf[0] == decimalNegSmall:
		if err := decodeNonsortingDecimalValue(dec, true, buf[1:], tmp); err != nil {
			return err
		}
		dec.Negative = true
		return nil
	case buf[0] == decimalPosSmall:
		if err := decodeNonsortingDecimalValue(dec, true, buf[1:], tmp); err != nil {
			return err
		}
		return nil
	case buf[0] == decimalPosMedium:
		decodeNonsortingDecimalValueWithoutExp(dec, buf[1:], tmp)
		return nil
	case buf[0] == decimalPosLarge:
		if err := decodeNonsortingDecimalValue(dec, false, buf[1:], tmp); err != nil {
			return err
		}
		return nil
	default:
		return errors.Errorf("unknown decimal prefix of the encoded byte slice: %q", buf)
	}
}

func decodeNonsortingDecimalValue(dec *apd.Decimal, negExp bool, buf, tmp []byte) error {
	// Decode the exponent.