remove some integer casts from slice iter

This commit is contained in:
Maybe Waffle 2022-09-04 20:45:29 +04:00
parent b11bf65e4a
commit fff92d5238

View File

@ -64,7 +64,7 @@ macro_rules! iterator {
// backwards by `n`. `n` must not exceed `self.len()`.
macro_rules! zst_shrink {
($self: ident, $n: ident) => {
$self.end = $self.end.wrapping_byte_offset(-$n);
$self.end = $self.end.wrapping_byte_sub($n);
}
}
@ -82,7 +82,7 @@ macro_rules! iterator {
// returning the old start.
// Unsafe because the offset must not exceed `self.len()`.
#[inline(always)]
unsafe fn post_inc_start(&mut self, offset: isize) -> * $raw_mut T {
unsafe fn post_inc_start(&mut self, offset: usize) -> * $raw_mut T {
if mem::size_of::<T>() == 0 {
zst_shrink!(self, offset);
self.ptr.as_ptr()
@ -90,7 +90,7 @@ macro_rules! iterator {
let old = self.ptr.as_ptr();
// SAFETY: the caller guarantees that `offset` doesn't exceed `self.len()`,
// so this new pointer is inside `self` and thus guaranteed to be non-null.
self.ptr = unsafe { NonNull::new_unchecked(self.ptr.as_ptr().offset(offset)) };
self.ptr = unsafe { NonNull::new_unchecked(self.ptr.as_ptr().add(offset)) };
old
}
}
@ -99,7 +99,7 @@ macro_rules! iterator {
// returning the new end.
// Unsafe because the offset must not exceed `self.len()`.
#[inline(always)]
unsafe fn pre_dec_end(&mut self, offset: isize) -> * $raw_mut T {
unsafe fn pre_dec_end(&mut self, offset: usize) -> * $raw_mut T {
if mem::size_of::<T>() == 0 {
zst_shrink!(self, offset);
self.ptr.as_ptr()
@ -107,7 +107,7 @@ macro_rules! iterator {
// SAFETY: the caller guarantees that `offset` doesn't exceed `self.len()`,
// which is guaranteed to not overflow an `isize`. Also, the resulting pointer
// is in bounds of `slice`, which fulfills the other requirements for `offset`.
self.end = unsafe { self.end.offset(-offset) };
self.end = unsafe { self.end.sub(offset) };
self.end
}
}
@ -180,7 +180,7 @@ macro_rules! iterator {
}
// SAFETY: We are in bounds. `post_inc_start` does the right thing even for ZSTs.
unsafe {
self.post_inc_start(n as isize);
self.post_inc_start(n);
Some(next_unchecked!(self))
}
}
@ -189,7 +189,7 @@ macro_rules! iterator {
fn advance_by(&mut self, n: usize) -> Result<(), usize> {
let advance = cmp::min(len!(self), n);
// SAFETY: By construction, `advance` does not exceed `self.len()`.
unsafe { self.post_inc_start(advance as isize) };
unsafe { self.post_inc_start(advance) };
if advance == n { Ok(()) } else { Err(advance) }
}
@ -375,7 +375,7 @@ macro_rules! iterator {
}
// SAFETY: We are in bounds. `pre_dec_end` does the right thing even for ZSTs.
unsafe {
self.pre_dec_end(n as isize);
self.pre_dec_end(n);
Some(next_back_unchecked!(self))
}
}
@ -384,7 +384,7 @@ macro_rules! iterator {
fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
let advance = cmp::min(len!(self), n);
// SAFETY: By construction, `advance` does not exceed `self.len()`.
unsafe { self.pre_dec_end(advance as isize) };
unsafe { self.pre_dec_end(advance) };
if advance == n { Ok(()) } else { Err(advance) }
}
}