native endianness

native.go

package foo

import (
	"encoding/binary"
	"unsafe"
)

var NativeEndianV1 = func() binary.ByteOrder {
	switch *(*uint32)(unsafe.Pointer(&[4]byte{1, 2, 3, 4})) {
	case 0x01020304:
		return binary.BigEndian
	case 0x04030201:
		return binary.LittleEndian
	default:
		panic("unknown endianness")
	}
}()

var NativeEndianV2 = [2]binary.ByteOrder{binary.LittleEndian, binary.BigEndian}[*(*uint16)(unsafe.Pointer(&[2]byte{0, 1}))&1]