Function decodeVarint

proto/decode.go:32–56

(b []byte)

var errVarintOverflow = errors.New("varint overflowed 64 bits integer")

func decodeVarint(b []byte) (uint64, int, error) {
	if len(b) != 0 && b[0] < 0x80 {
		// Fast-path for decoding the common case of varints that fit on a
		// single byte.
		//
		// This path is ~60% faster than calling binary.Uvarint.
		return uint64(b[0]), 1, nil
	}

	var x uint64
	var s uint

	for i, c := range b {
		if c < 0x80 {
			if i > 9 || i == 9 && c > 1 {
				return 0, i, errVarintOverflow
			}
			return x | uint64(c)<<s, i + 1, nil
		}
		x |= uint64(c&0x7f) << s
		s += 7
	}

	return x, len(b), io.ErrUnexpectedEOF
}

func decodeVarintZigZag(b []byte) (int64, int, error) {
	v, n, err := decodeVarint(b)