/// {
/// return null_mut();
/// };
-/// (self.arena.get() as *mut u8).add(allocated)
+/// self.arena.get().cast::<u8>().add(allocated)
/// }
/// unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
/// }
/// Accessing adjacent `u8` as `u16`
///
/// ```
- /// # fn foo(n: usize) {
- /// # use std::mem::align_of;
+ /// use std::mem::align_of;
+ ///
/// # unsafe {
- /// let x = [5u8, 6u8, 7u8, 8u8, 9u8];
- /// let ptr = x.as_ptr().add(n) as *const u8;
+ /// let x = [5_u8, 6, 7, 8, 9];
+ /// let ptr = x.as_ptr();
/// let offset = ptr.align_offset(align_of::<u16>());
- /// if offset < x.len() - n - 1 {
- /// let u16_ptr = ptr.add(offset) as *const u16;
- /// assert_ne!(*u16_ptr, 500);
+ ///
+ /// if offset < x.len() - 1 {
+ /// let u16_ptr = ptr.add(offset).cast::<u16>();
+ /// assert!(*u16_ptr == u16::from_ne_bytes([5, 6]) || *u16_ptr == u16::from_ne_bytes([6, 7]));
/// } else {
/// // while the pointer can be aligned via `offset`, it would point
/// // outside the allocation
/// }
- /// # } }
+ /// # }
/// ```
#[stable(feature = "align_offset", since = "1.36.0")]
#[rustc_const_unstable(feature = "const_align_offset", issue = "90962")]
/// Accessing adjacent `u8` as `u16`
///
/// ```
- /// # fn foo(n: usize) {
- /// # use std::mem::align_of;
+ /// use std::mem::align_of;
+ ///
/// # unsafe {
- /// let x = [5u8, 6u8, 7u8, 8u8, 9u8];
- /// let ptr = x.as_ptr().add(n) as *const u8;
+ /// let mut x = [5_u8, 6, 7, 8, 9];
+ /// let ptr = x.as_mut_ptr();
/// let offset = ptr.align_offset(align_of::<u16>());
- /// if offset < x.len() - n - 1 {
- /// let u16_ptr = ptr.add(offset) as *const u16;
- /// assert_ne!(*u16_ptr, 500);
+ ///
+ /// if offset < x.len() - 1 {
+ /// let u16_ptr = ptr.add(offset).cast::<u16>();
+ /// *u16_ptr = 0;
+ ///
+ /// assert!(x == [0, 0, 7, 8, 9] || x == [5, 0, 0, 8, 9]);
/// } else {
/// // while the pointer can be aligned via `offset`, it would point
/// // outside the allocation
/// }
- /// # } }
+ /// # }
/// ```
#[stable(feature = "align_offset", since = "1.36.0")]
#[rustc_const_unstable(feature = "const_align_offset", issue = "90962")]
assume(!ptr.is_null());
let end = if mem::size_of::<T>() == 0 {
- (ptr as *const u8).wrapping_add(slice.len()) as *const T
+ ptr.wrapping_byte_add(slice.len())
} else {
ptr.add(slice.len())
};
assume(!ptr.is_null());
let end = if mem::size_of::<T>() == 0 {
- (ptr as *mut u8).wrapping_add(slice.len()) as *mut T
+ ptr.wrapping_byte_add(slice.len())
} else {
ptr.add(slice.len())
};
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 }
+ unsafe { DATA.as_ptr().byte_add(1) }
}
#[test]
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;
+ let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
ptr::write_unaligned(unaligned_ptr, u16::from_ne_bytes([0x23, 0x45]));
}
two_aligned
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;
+ let unaligned_ptr = two_aligned.as_mut_ptr().byte_add(1);
unaligned_ptr.write_unaligned(u16::from_ne_bytes([0x23, 0x45]));
}
two_aligned
#![feature(const_maybe_uninit_assume_init_read)]
#![feature(const_nonnull_new)]
#![feature(const_num_from_num)]
+#![feature(const_pointer_byte_offsets)]
#![feature(const_ptr_as_ref)]
#![feature(const_ptr_read)]
#![feature(const_ptr_write)]
#![feature(never_type)]
#![feature(unwrap_infallible)]
#![feature(result_into_ok_or_err)]
+#![feature(pointer_byte_offsets)]
#![feature(portable_simd)]
#![feature(ptr_metadata)]
#![feature(once_cell)]
/// * the pointer is null.
/// * the pointed-to range is not in user memory.
unsafe fn check_ptr(ptr: *const Self) {
- let is_aligned = |p| -> bool { 0 == (p as usize) & (Self::align_of() - 1) };
+ let is_aligned = |p: *const u8| -> bool { 0 == p.addr() & (Self::align_of() - 1) };
assert!(is_aligned(ptr as *const u8));
assert!(is_user_range(ptr as _, mem::size_of_val(unsafe { &*ptr })));
use crate::alloc::{GlobalAlloc, Layout, System};
+use crate::ptr::null_mut;
#[stable(feature = "alloc_system_type", since = "1.28.0")]
unsafe impl GlobalAlloc for System {
#[inline]
unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
- 0 as *mut u8
+ null_mut()
}
#[inline]
unsafe fn alloc_zeroed(&self, _layout: Layout) -> *mut u8 {
- 0 as *mut u8
+ null_mut()
}
#[inline]
#[inline]
unsafe fn realloc(&self, _ptr: *mut u8, _layout: Layout, _new_size: usize) -> *mut u8 {
- 0 as *mut u8
+ null_mut()
}
}