71 lines
1.5 KiB
Rust
71 lines
1.5 KiB
Rust
#[repr(C)]
|
|
#[derive(Clone, Copy)]
|
|
struct Pair<T, U>(T, U);
|
|
#[repr(C)]
|
|
#[derive(Clone, Copy)]
|
|
struct Triple<T>(T, T, T);
|
|
|
|
#[repr(C)]
|
|
union U<A: Copy, B: Copy> {
|
|
a: Pair<A, A>,
|
|
b: B,
|
|
}
|
|
|
|
#[repr(C)]
|
|
union W<A: Copy, B: Copy> {
|
|
a: A,
|
|
b: B,
|
|
}
|
|
|
|
#[cfg(target_endian = "little")]
|
|
unsafe fn check() {
|
|
let mut u = U::<u8, u16> { b: 0xDE_DE };
|
|
u.a.0 = 0xBE;
|
|
assert_eq!(u.b, 0xDE_BE);
|
|
|
|
let mut u = U::<u16, u32> { b: 0xDEAD_DEAD };
|
|
u.a.0 = 0xBEEF;
|
|
assert_eq!(u.b, 0xDEAD_BEEF);
|
|
|
|
let mut u = U::<u32, u64> { b: 0xDEADBEEF_DEADBEEF };
|
|
u.a.0 = 0xBAADF00D;
|
|
assert_eq!(u.b, 0xDEADBEEF_BAADF00D);
|
|
|
|
let mut w = W::<Pair<Triple<u8>, u8>, u32> { b: 0xDEAD_DEAD };
|
|
w.a.0 = Triple(0, 0, 0);
|
|
assert_eq!(w.b, 0xDE00_0000);
|
|
|
|
let mut w = W::<Pair<u8, Triple<u8>>, u32> { b: 0xDEAD_DEAD };
|
|
w.a.1 = Triple(0, 0, 0);
|
|
assert_eq!(w.b, 0x0000_00AD);
|
|
}
|
|
|
|
#[cfg(target_endian = "big")]
|
|
unsafe fn check() {
|
|
let mut u = U::<u8, u16> { b: 0xDE_DE };
|
|
u.a.0 = 0xBE;
|
|
assert_eq!(u.b, 0xBE_DE);
|
|
|
|
let mut u = U::<u16, u32> { b: 0xDEAD_DEAD };
|
|
u.a.0 = 0xBEEF;
|
|
assert_eq!(u.b, 0xBEEF_DEAD);
|
|
|
|
let mut u = U::<u32, u64> { b: 0xDEADBEEF_DEADBEEF };
|
|
u.a.0 = 0xBAADF00D;
|
|
assert_eq!(u.b, 0xBAADF00D_DEADBEEF);
|
|
|
|
let mut w = W::<Pair<Triple<u8>, u8>, u32> { b: 0xDEAD_DEAD };
|
|
w.a.0 = Triple(0, 0, 0);
|
|
assert_eq!(w.b, 0x0000_00AD);
|
|
|
|
let mut w = W::<Pair<u8, Triple<u8>>, u32> { b: 0xDEAD_DEAD };
|
|
w.a.1 = Triple(0, 0, 0);
|
|
assert_eq!(w.b, 0xDE00_0000);
|
|
}
|
|
|
|
fn main() {
|
|
unsafe {
|
|
check();
|
|
}
|
|
}
|