51 lines
1.6 KiB
Rust
51 lines
1.6 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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