Function DecodeVarintAscending

pkg/util/encoding/encoding.go:363–392

DecodeVarintAscending decodes a value encoded by EncodeVarintAscending.

(b []byte)

// DecodeVarintAscending decodes a value encoded by EncodeVarintAscending.
func DecodeVarintAscending(b []byte) ([]byte, int64, error) {
	if len(b) == 0 {
		return nil, 0, errors.Errorf("insufficient bytes to decode varint value")
	}
	length := int(b[0]) - intZero
	if length < 0 {
		length = -length
		remB := b[1:]
		if len(remB) < length {
			return nil, 0, errors.Errorf("insufficient bytes to decode varint value: %q", remB)
		}
		var v int64
		// Use the ones-complement of each encoded byte in order to build
		// up a positive number, then take the ones-complement again to
		// arrive at our negative value.
		for _, t := range remB[:length] {
			v = (v << 8) | int64(^t)
		}
		return remB[length:], ^v, nil
	}

	remB, v, err := DecodeUvarintAscending(b)
	if err != nil {
		return remB, 0, err
	}
	if v > math.MaxInt64 {
		return nil, 0, errors.Errorf("varint %d overflows int64", v)
	}
	return remB, int64(v), nil
}

// DecodeVarintDescending decodes a int64 value which was encoded
// using EncodeVarintDescending.