diff options
Diffstat (limited to 'library/core/tests/const_ptr.rs')
-rw-r--r-- | library/core/tests/const_ptr.rs | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/library/core/tests/const_ptr.rs b/library/core/tests/const_ptr.rs new file mode 100644 index 000000000..152fed803 --- /dev/null +++ b/library/core/tests/const_ptr.rs @@ -0,0 +1,101 @@ +// Aligned to two bytes +const DATA: [u16; 2] = [u16::from_ne_bytes([0x01, 0x23]), u16::from_ne_bytes([0x45, 0x67])]; + +const fn unaligned_ptr() -> *const u16 { + // Since DATA.as_ptr() is aligned to two bytes, adding 1 byte to that produces an unaligned *const u16 + unsafe { (DATA.as_ptr() as *const u8).add(1) as *const u16 } +} + +#[test] +fn read() { + use core::ptr; + + const FOO: i32 = unsafe { ptr::read(&42 as *const i32) }; + assert_eq!(FOO, 42); + + const ALIGNED: i32 = unsafe { ptr::read_unaligned(&42 as *const i32) }; + assert_eq!(ALIGNED, 42); + + const UNALIGNED_PTR: *const u16 = unaligned_ptr(); + + const UNALIGNED: u16 = unsafe { ptr::read_unaligned(UNALIGNED_PTR) }; + assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); +} + +#[test] +fn const_ptr_read() { + const FOO: i32 = unsafe { (&42 as *const i32).read() }; + assert_eq!(FOO, 42); + + const ALIGNED: i32 = unsafe { (&42 as *const i32).read_unaligned() }; + assert_eq!(ALIGNED, 42); + + const UNALIGNED_PTR: *const u16 = unaligned_ptr(); + + const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() }; + assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); +} + +#[test] +fn mut_ptr_read() { + const FOO: i32 = unsafe { (&42 as *const i32 as *mut i32).read() }; + assert_eq!(FOO, 42); + + const ALIGNED: i32 = unsafe { (&42 as *const i32 as *mut i32).read_unaligned() }; + assert_eq!(ALIGNED, 42); + + const UNALIGNED_PTR: *mut u16 = unaligned_ptr() as *mut u16; + + const UNALIGNED: u16 = unsafe { UNALIGNED_PTR.read_unaligned() }; + assert_eq!(UNALIGNED, u16::from_ne_bytes([0x23, 0x45])); +} + +#[test] +fn write() { + use core::ptr; + + const fn write_aligned() -> i32 { + let mut res = 0; + unsafe { + ptr::write(&mut res as *mut _, 42); + } + res + } + const ALIGNED: i32 = write_aligned(); + assert_eq!(ALIGNED, 42); + + const fn write_unaligned() -> [u16; 2] { + let mut two_aligned = [0u16; 2]; + unsafe { + let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16; + ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45])); + } + two_aligned + } + const UNALIGNED: [u16; 2] = write_unaligned(); + assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]); +} + +#[test] +fn mut_ptr_write() { + const fn aligned() -> i32 { + let mut res = 0; + unsafe { + (&mut res as *mut i32).write(42); + } + res + } + const ALIGNED: i32 = aligned(); + assert_eq!(ALIGNED, 42); + + const fn write_unaligned() -> [u16; 2] { + let mut two_aligned = [0u16; 2]; + unsafe { + let unaligned_ptr = (two_aligned.as_mut_ptr() as *mut u8).add(1) as *mut u16; + unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45])); + } + two_aligned + } + const UNALIGNED: [u16; 2] = write_unaligned(); + assert_eq!(UNALIGNED, [u16::from_ne_bytes([0x00, 0x23]), u16::from_ne_bytes([0x45, 0x00])]); +} |