102 lines
3.1 KiB
Rust
102 lines
3.1 KiB
Rust
// Aligned to two bytes
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const DATA: [u16; 2] = [u16::from_ne_bytes([0x01, 0x23]), u16::from_ne_bytes([0x45, 0x67])];
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const fn unaligned_ptr() -> *const u16 {
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// Since DATA.as_ptr() is aligned to two bytes, adding 1 byte to that produces an unaligned *const u16
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unsafe { (DATA.as_ptr() as *const u8).add(1) as *const u16 }
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}
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#[test]
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fn read() {
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use core::ptr;
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const FOO: i32 = unsafe { ptr::read(&42 as *const i32) };
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assert_eq!(FOO, 42);
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const ALIGNED: i32 = unsafe { ptr::read_unaligned(&42 as *const i32) };
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assert_eq!(ALIGNED, 42);
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const UNALIGNED_PTR: *const u16 = unaligned_ptr();
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const UNALIGNED: u16 = unsafe { ptr::read_unaligned(UNALIGNED_PTR) };
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assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
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}
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#[test]
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fn const_ptr_read() {
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const FOO: i32 = unsafe { (&42 as *const i32).read() };
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assert_eq!(FOO, 42);
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const ALIGNED: i32 = unsafe { (&42 as *const i32).read_unaligned() };
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assert_eq!(ALIGNED, 42);
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const UNALIGNED_PTR: *const u16 = unaligned_ptr();
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const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() };
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assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
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}
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#[test]
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fn mut_ptr_read() {
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const FOO: i32 = unsafe { (&42 as *const i32 as *mut i32).read() };
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assert_eq!(FOO, 42);
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const ALIGNED: i32 = unsafe { (&42 as *const i32 as *mut i32).read_unaligned() };
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assert_eq!(ALIGNED, 42);
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const UNALIGNED_PTR: *mut u16 = unaligned_ptr() as *mut u16;
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const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() };
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assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45]));
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}
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//#[test]
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//fn write() {
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// use core::ptr;
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//
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// const fn write_aligned() -> i32 {
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// let mut res = 0;
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// unsafe {
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// ptr::write(&mut res as *mut _, 42);
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// }
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// res
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// }
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// const ALIGNED: i32 = write_aligned();
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// assert_eq!(ALIGNED, 42);
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//
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// const fn write_unaligned() -> [u16; 2] {
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// let mut two_aligned = [0u16; 2];
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// unsafe {
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// let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16;
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// ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45]));
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// }
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// two_aligned
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// }
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// const UNALIGNED: [u16; 2] = write_unaligned();
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// assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]);
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//}
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//#[test]
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//fn mut_ptr_write() {
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// const fn aligned() -> i32 {
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// let mut res = 0;
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// unsafe {
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// (&mut res as *mut i32).write(42);
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// }
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// res
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// }
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// const ALIGNED: i32 = aligned();
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// assert_eq!(ALIGNED, 42);
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//
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// const fn write_unaligned() -> [u16; 2] {
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// let mut two_aligned = [0u16; 2];
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// unsafe {
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// let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16;
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// unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45]));
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// }
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// two_aligned
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// }
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// const UNALIGNED: [u16; 2] = write_unaligned();
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// assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]);
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//}
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