Method Scan

pgtype/numeric.go:602–706

(src []byte, dst any)

type scanPlanBinaryNumericToNumericScanner struct{}

func (scanPlanBinaryNumericToNumericScanner) Scan(src []byte, dst any) error {
	scanner := (dst).(NumericScanner)

	if src == nil {
		return scanner.ScanNumeric(Numeric{})
	}

	if len(src) < 8 {
		return fmt.Errorf("numeric incomplete %v", src)
	}

	rp := 0
	ndigits := binary.BigEndian.Uint16(src[rp:])
	rp += 2
	weight := int16(binary.BigEndian.Uint16(src[rp:]))
	rp += 2
	sign := binary.BigEndian.Uint16(src[rp:])
	rp += 2
	dscale := int16(binary.BigEndian.Uint16(src[rp:]))
	rp += 2

	switch sign {
	case pgNumericNaNSign:
		return scanner.ScanNumeric(Numeric{NaN: true, Valid: true})
	case pgNumericPosInfSign:
		return scanner.ScanNumeric(Numeric{InfinityModifier: Infinity, Valid: true})
	case pgNumericNegInfSign:
		return scanner.ScanNumeric(Numeric{InfinityModifier: NegativeInfinity, Valid: true})
	}

	if ndigits == 0 {
		return scanner.ScanNumeric(Numeric{Int: big.NewInt(0), Valid: true})
	}

	if len(src[rp:]) < int(ndigits)*2 {
		return fmt.Errorf("numeric incomplete %v", src)
	}

	accum := &big.Int{}

	for i := 0; i < int(ndigits+3)/4; i++ {
		int64accum, bytesRead, digitsRead := nbaseDigitsToInt64(src[rp:])
		rp += bytesRead

		if i > 0 {
			var mul *big.Int
			switch digitsRead {
			case 1:
				mul = bigNBase
			case 2:
				mul = bigNBaseX2
			case 3:
				mul = bigNBaseX3
			case 4:
				mul = bigNBaseX4
			default:
				return fmt.Errorf("invalid digitsRead: %d (this can't happen)", digitsRead)
			}