Auto merge of #73951 - pickfire:liballoc-intoiter, r=Mark-Simulacrum

Liballoc intoiter refactor
This commit is contained in:
bors 2020-09-11 23:52:03 +00:00
commit 12c10e34a4

View File

@ -2882,25 +2882,21 @@ impl<T> Iterator for IntoIter<T> {
#[inline] #[inline]
fn next(&mut self) -> Option<T> { fn next(&mut self) -> Option<T> {
unsafe { if self.ptr as *const _ == self.end {
if self.ptr as *const _ == self.end { None
None } else if mem::size_of::<T>() == 0 {
} else { // purposefully don't use 'ptr.offset' because for
if mem::size_of::<T>() == 0 { // vectors with 0-size elements this would return the
// purposefully don't use 'ptr.offset' because for // same pointer.
// vectors with 0-size elements this would return the self.ptr = unsafe { arith_offset(self.ptr as *const i8, 1) as *mut T };
// same pointer.
self.ptr = arith_offset(self.ptr as *const i8, 1) as *mut T;
// Make up a value of this ZST. // Make up a value of this ZST.
Some(mem::zeroed()) Some(unsafe { mem::zeroed() })
} else { } else {
let old = self.ptr; let old = self.ptr;
self.ptr = self.ptr.offset(1); self.ptr = unsafe { self.ptr.offset(1) };
Some(ptr::read(old)) Some(unsafe { ptr::read(old) })
}
}
} }
} }
@ -2935,22 +2931,18 @@ impl<T> Iterator for IntoIter<T> {
impl<T> DoubleEndedIterator for IntoIter<T> { impl<T> DoubleEndedIterator for IntoIter<T> {
#[inline] #[inline]
fn next_back(&mut self) -> Option<T> { fn next_back(&mut self) -> Option<T> {
unsafe { if self.end == self.ptr {
if self.end == self.ptr { None
None } else if mem::size_of::<T>() == 0 {
} else { // See above for why 'ptr.offset' isn't used
if mem::size_of::<T>() == 0 { self.end = unsafe { arith_offset(self.end as *const i8, -1) as *mut T };
// See above for why 'ptr.offset' isn't used
self.end = arith_offset(self.end as *const i8, -1) as *mut T;
// Make up a value of this ZST. // Make up a value of this ZST.
Some(mem::zeroed()) Some(unsafe { mem::zeroed() })
} else { } else {
self.end = self.end.offset(-1); self.end = unsafe { self.end.offset(-1) };
Some(ptr::read(self.end)) Some(unsafe { ptr::read(self.end) })
}
}
} }
} }
} }