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replace advance_by returning usize with Result<(), NonZeroUsize>

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The 8472
2023-03-13 20:07:53 +01:00
parent 69db91b8b2
commit e29b27b4a4
31 changed files with 340 additions and 271 deletions
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25
library/core/src/iter/range.rs
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@@ -1,6 +1,7 @@
use crate::convert::TryFrom;
use crate::marker::Destruct;
use crate::mem;
use crate::num::NonZeroUsize;
use crate::ops::{self, Try};
use super::{
@@ -530,12 +531,12 @@ trait RangeIteratorImpl {
// Iterator
fn spec_next(&mut self) -> Option<Self::Item>;
fn spec_nth(&mut self, n: usize) -> Option<Self::Item>;
fn spec_advance_by(&mut self, n: usize) -> usize;
fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize>;
// DoubleEndedIterator
fn spec_next_back(&mut self) -> Option<Self::Item>;
fn spec_nth_back(&mut self, n: usize) -> Option<Self::Item>;
fn spec_advance_back_by(&mut self, n: usize) -> usize;
fn spec_advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize>;
}
impl<A: ~const Step + ~const Destruct> const RangeIteratorImpl for ops::Range<A> {
@@ -567,7 +568,7 @@ impl<A: ~const Step + ~const Destruct> const RangeIteratorImpl for ops::Range<A>
}
#[inline]
default fn spec_advance_by(&mut self, n: usize) -> usize {
default fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let available = if self.start <= self.end {
Step::steps_between(&self.start, &self.end).unwrap_or(usize::MAX)
} else {
@@ -579,7 +580,7 @@ impl<A: ~const Step + ~const Destruct> const RangeIteratorImpl for ops::Range<A>
self.start =
Step::forward_checked(self.start.clone(), taken).expect("`Step` invariants not upheld");
n - taken
NonZeroUsize::new(n - taken).map_or(Ok(()), Err)
}
#[inline]
@@ -608,7 +609,7 @@ impl<A: ~const Step + ~const Destruct> const RangeIteratorImpl for ops::Range<A>
}
#[inline]
default fn spec_advance_back_by(&mut self, n: usize) -> usize {
default fn spec_advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let available = if self.start <= self.end {
Step::steps_between(&self.start, &self.end).unwrap_or(usize::MAX)
} else {
@@ -620,7 +621,7 @@ impl<A: ~const Step + ~const Destruct> const RangeIteratorImpl for ops::Range<A>
self.end =
Step::backward_checked(self.end.clone(), taken).expect("`Step` invariants not upheld");
n - taken
NonZeroUsize::new(n - taken).map_or(Ok(()), Err)
}
}
@@ -651,7 +652,7 @@ impl<T: ~const TrustedStep + ~const Destruct> const RangeIteratorImpl for ops::R
}
#[inline]
fn spec_advance_by(&mut self, n: usize) -> usize {
fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let available = if self.start <= self.end {
Step::steps_between(&self.start, &self.end).unwrap_or(usize::MAX)
} else {
@@ -666,7 +667,7 @@ impl<T: ~const TrustedStep + ~const Destruct> const RangeIteratorImpl for ops::R
// Otherwise 0 is returned which always safe to use.
self.start = unsafe { Step::forward_unchecked(self.start.clone(), taken) };
n - taken
NonZeroUsize::new(n - taken).map_or(Ok(()), Err)
}
#[inline]
@@ -695,7 +696,7 @@ impl<T: ~const TrustedStep + ~const Destruct> const RangeIteratorImpl for ops::R
}
#[inline]
fn spec_advance_back_by(&mut self, n: usize) -> usize {
fn spec_advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let available = if self.start <= self.end {
Step::steps_between(&self.start, &self.end).unwrap_or(usize::MAX)
} else {
@@ -707,7 +708,7 @@ impl<T: ~const TrustedStep + ~const Destruct> const RangeIteratorImpl for ops::R
// SAFETY: same as the spec_advance_by() implementation
self.end = unsafe { Step::backward_unchecked(self.end.clone(), taken) };
n - taken
NonZeroUsize::new(n - taken).map_or(Ok(()), Err)
}
}
@@ -757,7 +758,7 @@ impl<A: ~const Step + ~const Destruct> const Iterator for ops::Range<A> {
}
#[inline]
fn advance_by(&mut self, n: usize) -> usize {
fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
self.spec_advance_by(n)
}
@@ -836,7 +837,7 @@ impl<A: ~const Step + ~const Destruct> const DoubleEndedIterator for ops::Range<
}
#[inline]
fn advance_back_by(&mut self, n: usize) -> usize {
fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
self.spec_advance_back_by(n)
}
}