1 // Aligned to two bytes
2 const DATA: [u16; 2] = [u16::from_ne_bytes([0x01, 0x23]), u16::from_ne_bytes([0x45, 0x67])];
4 const fn unaligned_ptr() -> *const u16 {
5 // Since DATA.as_ptr() is aligned to two bytes, adding 1 byte to that produces an unaligned *const u16
6 unsafe { DATA.as_ptr().byte_add(1) }
13 const FOO: i32 = unsafe { ptr::read(&42 as *const i32) };
16 const ALIGNED: i32 = unsafe { ptr::read_unaligned(&42 as *const i32) };
17 assert_eq!(ALIGNED, 42);
19 const UNALIGNED_PTR: *const u16 = unaligned_ptr();
21 const UNALIGNED: u16 = unsafe { ptr::read_unaligned(UNALIGNED_PTR) };
22 assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
27 const FOO: i32 = unsafe { (&42 as *const i32).read() };
30 const ALIGNED: i32 = unsafe { (&42 as *const i32).read_unaligned() };
31 assert_eq!(ALIGNED, 42);
33 const UNALIGNED_PTR: *const u16 = unaligned_ptr();
35 const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() };
36 assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
41 const FOO: i32 = unsafe { (&42 as *const i32 as *mut i32).read() };
44 const ALIGNED: i32 = unsafe { (&42 as *const i32 as *mut i32).read_unaligned() };
45 assert_eq!(ALIGNED, 42);
47 const UNALIGNED_PTR: *mut u16 = unaligned_ptr() as *mut u16;
49 const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() };
50 assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
57 const fn write_aligned() -> i32 {
60 ptr::write(&mut res as *mut _, 42);
64 const ALIGNED: i32 = write_aligned();
65 assert_eq!(ALIGNED, 42);
67 const fn write_unaligned() -> [u16; 2] {
68 let mut two_aligned = [0u16; 2];
70 let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
71 ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45]));
75 const UNALIGNED: [u16; 2] = write_unaligned();
76 assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]);
81 const fn aligned() -> i32 {
84 (&mut res as *mut i32).write(42);
88 const ALIGNED: i32 = aligned();
89 assert_eq!(ALIGNED, 42);
91 const fn write_unaligned() -> [u16; 2] {
92 let mut two_aligned = [0u16; 2];
94 let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
95 unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45]));
99 const UNALIGNED: [u16; 2] = write_unaligned();
100 assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]);