Function isZeroBytes

proto/bytes.go:86–115

isZeroBytes is an optimized version of this loop: for i := range b { if b[i] != 0 { return false } } return true This implementation significantly reduces the CPU footprint of checking for slices to be zero, especially when the length increases (these cases should be rare tho). name

(b []byte)

// IsZeroBytes7    3.97ns ± 4%  3.26ns ± 3%  -18.02%  (p=0.000 n=10+10)
// IsZeroBytes64K  14.8µs ± 3%   1.9µs ± 3%  -87.34%  (p=0.000 n=10+10)
func isZeroBytes(b []byte) bool {
	if n := len(b) / 8; n != 0 {
		if !isZeroUint64(*(*[]uint64)(unsafe.Pointer(&sliceHeader{
			Data: unsafe.Pointer(&b[0]),
			Len:  n,
			Cap:  n,
		}))) {
			return false
		}
		b = b[n*8:]
	}
	switch len(b) {
	case 7:
		return bto32(b) == 0 && bto16(b[4:]) == 0 && b[6] == 0
	case 6:
		return bto32(b) == 0 && bto16(b[4:]) == 0
	case 5:
		return bto32(b) == 0 && b[4] == 0
	case 4:
		return bto32(b) == 0
	case 3:
		return bto16(b) == 0 && b[2] == 0
	case 2:
		return bto16(b) == 0
	case 1:
		return b[0] == 0
	default:
		return true
	}
}

func bto32(b []byte) uint32 {
	return *(*uint32)(unsafe.Pointer(&b[0]))