#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
- let diff = (self.end as usize).wrapping_sub(self.ptr as usize);
- let size = mem::size_of::<T>();
- let exact = diff / (if size == 0 {1} else {size});
+ let exact = ptrdistance(self.ptr, self.end);
(exact, Some(exact))
}
unsafe impl<'a, T> TrustedLen for IterMut<'a, T> {}
+// 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 {
+ let diff = (end as usize).wrapping_sub(start as usize);
+ let size = mem::size_of::<T>();
+ diff / (if size == 0 { 1 } else { size })
+}
+
// Extension methods for raw pointers, used by the iterators
trait PointerExt : Copy {
unsafe fn slice_offset(self, i: isize) -> Self;