#![feature(lang_items)]
#![feature(needs_allocator)]
#![feature(nonzero)]
-#![feature(offset_to)]
#![feature(optin_builtin_traits)]
#![feature(pattern)]
#![feature(pin)]
#![feature(placement_in_syntax)]
#![feature(placement_new_protocol)]
#![feature(ptr_internals)]
+#![feature(ptr_offset_from)]
#![feature(rustc_attrs)]
#![feature(slice_get_slice)]
#![feature(slice_rsplit)]
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
- let exact = match self.ptr.offset_to(self.end) {
- Some(x) => x as usize,
- None => (self.end as usize).wrapping_sub(self.ptr as usize),
+ let exact = if mem::size_of::<T>() == 0 {
+ (self.end as usize).wrapping_sub(self.ptr as usize)
+ } else {
+ unsafe { self.end.offset_from(self.ptr) as usize }
};
(exact, Some(exact))
}
///
/// ```
/// #![feature(offset_to)]
+ /// #![allow(deprecated)]
///
/// fn main() {
/// let a = [0; 5];
/// }
/// ```
#[unstable(feature = "offset_to", issue = "41079")]
+ #[rustc_deprecated(since = "1.27.0", reason = "Replaced by `wrapping_offset_from`, with the \
+ opposite argument order. If you're writing unsafe code, consider `offset_from`.")]
#[inline]
pub fn offset_to(self, other: *const T) -> Option<isize> where T: Sized {
let size = mem::size_of::<T>();
if size == 0 {
None
} else {
- let diff = (other as isize).wrapping_sub(self as isize);
- Some(diff / size as isize)
+ Some(other.wrapping_offset_from(self))
}
}
///
/// ```
/// #![feature(offset_to)]
+ /// #![allow(deprecated)]
///
/// fn main() {
/// let mut a = [0; 5];
/// }
/// ```
#[unstable(feature = "offset_to", issue = "41079")]
+ #[rustc_deprecated(since = "1.27.0", reason = "Replaced by `wrapping_offset_from`, with the \
+ opposite argument order. If you're writing unsafe code, consider `offset_from`.")]
#[inline]
pub fn offset_to(self, other: *const T) -> Option<isize> where T: Sized {
let size = mem::size_of::<T>();
if size == 0 {
None
} else {
- let diff = (other as isize).wrapping_sub(self as isize);
- Some(diff / size as isize)
+ Some(other.wrapping_offset_from(self))
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
- let exact = ptrdistance(self.ptr, self.end);
+ let exact = unsafe { ptrdistance(self.ptr, self.end) };
(exact, Some(exact))
}
// Return the number of elements of `T` from `start` to `end`.
// Return the arithmetic difference if `T` is zero size.
#[inline(always)]
-fn ptrdistance<T>(start: *const T, end: *const T) -> usize {
- match start.offset_to(end) {
- Some(x) => x as usize,
- None => (end as usize).wrapping_sub(start as usize),
+unsafe fn ptrdistance<T>(start: *const T, end: *const T) -> usize {
+ if mem::size_of::<T>() == 0 {
+ (end as usize).wrapping_sub(start as usize)
+ } else {
+ end.offset_from(start) as usize
}
}