projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| 5869c6ff XL |
1 | // Aligned to two bytes |
| 2 | const DATA: [u16; 2] = [u16::from_ne_bytes([0x01, 0x23]), u16::from_ne_bytes([0x45, 0x67])]; | |
| 3 | ||
| 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() as *const u8).add(1) as *const u16 } | |
| 7 | } | |
| 8 | ||
| 9 | #[test] | |
| 10 | fn read() { | |
| 11 | use core::ptr; | |
| 12 | ||
| 13 | const FOO: i32 = unsafe { ptr::read(&42 as *const i32) }; | |
| 14 | assert_eq!(FOO, 42); | |
| 15 | ||
| 16 | const ALIGNED: i32 = unsafe { ptr::read_unaligned(&42 as *const i32) }; | |
| 17 | assert_eq!(ALIGNED, 42); | |
| 18 | ||
| 19 | const UNALIGNED_PTR: *const u16 = unaligned_ptr(); | |
| 20 | ||
| 21 | const UNALIGNED: u16 = unsafe { ptr::read_unaligned(UNALIGNED_PTR) }; | |
| 22 | assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); | |
| 23 | } | |
| 24 | ||
| 25 | #[test] | |
| 26 | fn const_ptr_read() { | |
| 27 | const FOO: i32 = unsafe { (&42 as *const i32).read() }; | |
| 28 | assert_eq!(FOO, 42); | |
| 29 | ||
| 30 | const ALIGNED: i32 = unsafe { (&42 as *const i32).read_unaligned() }; | |
| 31 | assert_eq!(ALIGNED, 42); | |
| 32 | ||
| 33 | const UNALIGNED_PTR: *const u16 = unaligned_ptr(); | |
| 34 | ||
| 35 | const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() }; | |
| 36 | assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); | |
| 37 | } | |
| 38 | ||
| 39 | #[test] | |
| 40 | fn mut_ptr_read() { | |
| 41 | const FOO: i32 = unsafe { (&42 as *const i32 as *mut i32).read() }; | |
| 42 | assert_eq!(FOO, 42); | |
| 43 | ||
| 44 | const ALIGNED: i32 = unsafe { (&42 as *const i32 as *mut i32).read_unaligned() }; | |
| 45 | assert_eq!(ALIGNED, 42); | |
| 46 | ||
| 47 | const UNALIGNED_PTR: *mut u16 = unaligned_ptr() as *mut u16; | |
| 48 | ||
| 49 | const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() }; | |
| 50 | assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); | |
| 51 | } | |
| 6a06907d | 52 | |
| 36d6ef2b XL |
53 | //#[test] |
| 54 | //fn write() { | |
| 55 | // use core::ptr; | |
| 56 | // | |
| 57 | // const fn write_aligned() -> i32 { | |
| 58 | // let mut res = 0; | |
| 59 | // unsafe { | |
| 60 | // ptr::write(&mut res as *mut _, 42); | |
| 61 | // } | |
| 62 | // res | |
| 63 | // } | |
| 64 | // const ALIGNED: i32 = write_aligned(); | |
| 65 | // assert_eq!(ALIGNED, 42); | |
| 66 | // | |
| 67 | // const fn write_unaligned() -> [u16; 2] { | |
| 68 | // let mut two_aligned = [0u16; 2]; | |
| 69 | // unsafe { | |
| 70 | // let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16; | |
| 71 | // ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45])); | |
| 72 | // } | |
| 73 | // two_aligned | |
| 74 | // } | |
| 75 | // const UNALIGNED: [u16; 2] = write_unaligned(); | |
| 76 | // assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]); | |
| 77 | //} | |
| 78 | ||
| 79 | //#[test] | |
| 80 | //fn mut_ptr_write() { | |
| 81 | // const fn aligned() -> i32 { | |
| 82 | // let mut res = 0; | |
| 83 | // unsafe { | |
| 84 | // (&mut res as *mut i32).write(42); | |
| 85 | // } | |
| 86 | // res | |
| 87 | // } | |
| 88 | // const ALIGNED: i32 = aligned(); | |
| 89 | // assert_eq!(ALIGNED, 42); | |
| 90 | // | |
| 91 | // const fn write_unaligned() -> [u16; 2] { | |
| 92 | // let mut two_aligned = [0u16; 2]; | |
| 93 | // unsafe { | |
| 94 | // let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16; | |
| 95 | // unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45])); | |
| 96 | // } | |
| 97 | // two_aligned | |
| 98 | // } | |
| 99 | // const UNALIGNED: [u16; 2] = write_unaligned(); | |
| 100 | // assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]); | |
| 101 | //} |