diff options
Diffstat (limited to 'library/core')
26 files changed, 292 insertions, 263 deletions
diff --git a/library/core/src/array/iter.rs b/library/core/src/array/iter.rs index 8259c087d22..73e2c2cfbbe 100644 --- a/library/core/src/array/iter.rs +++ b/library/core/src/array/iter.rs @@ -1,5 +1,6 @@ //! Defines the `IntoIter` owned iterator for arrays. +use crate::num::NonZeroUsize; use crate::{ fmt, iter::{self, ExactSizeIterator, FusedIterator, TrustedLen}, @@ -284,12 +285,11 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> { self.next_back() } - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - let original_len = self.len(); - + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // This also moves the start, which marks them as conceptually "dropped", // so if anything goes bad then our drop impl won't double-free them. let range_to_drop = self.alive.take_prefix(n); + let remaining = n - range_to_drop.len(); // SAFETY: These elements are currently initialized, so it's fine to drop them. unsafe { @@ -297,7 +297,7 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> { ptr::drop_in_place(MaybeUninit::slice_assume_init_mut(slice)); } - if n > original_len { Err(original_len) } else { Ok(()) } + NonZeroUsize::new(remaining).map_or(Ok(()), Err) } } @@ -334,12 +334,11 @@ impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, N> { }) } - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { - let original_len = self.len(); - + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // This also moves the end, which marks them as conceptually "dropped", // so if anything goes bad then our drop impl won't double-free them. let range_to_drop = self.alive.take_suffix(n); + let remaining = n - range_to_drop.len(); // SAFETY: These elements are currently initialized, so it's fine to drop them. unsafe { @@ -347,7 +346,7 @@ impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, N> { ptr::drop_in_place(MaybeUninit::slice_assume_init_mut(slice)); } - if n > original_len { Err(original_len) } else { Ok(()) } + NonZeroUsize::new(remaining).map_or(Ok(()), Err) } } diff --git a/library/core/src/iter/adapters/by_ref_sized.rs b/library/core/src/iter/adapters/by_ref_sized.rs index 477e7117c3e..4e0e19ddc78 100644 --- a/library/core/src/iter/adapters/by_ref_sized.rs +++ b/library/core/src/iter/adapters/by_ref_sized.rs @@ -1,3 +1,4 @@ +use crate::num::NonZeroUsize; use crate::ops::{NeverShortCircuit, Try}; /// Like `Iterator::by_ref`, but requiring `Sized` so it can forward generics. @@ -26,7 +27,7 @@ impl<I: Iterator> Iterator for ByRefSized<'_, I> { } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { I::advance_by(self.0, n) } @@ -62,7 +63,7 @@ impl<I: DoubleEndedIterator> DoubleEndedIterator for ByRefSized<'_, I> { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { I::advance_back_by(self.0, n) } diff --git a/library/core/src/iter/adapters/chain.rs b/library/core/src/iter/adapters/chain.rs index d4b2640e81d..2046b70c9c6 100644 --- a/library/core/src/iter/adapters/chain.rs +++ b/library/core/src/iter/adapters/chain.rs @@ -1,4 +1,5 @@ use crate::iter::{DoubleEndedIterator, FusedIterator, Iterator, TrustedLen}; +use crate::num::NonZeroUsize; use crate::ops::Try; /// An iterator that links two iterators together, in a chain. @@ -95,38 +96,33 @@ where } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - let mut rem = n; - + fn advance_by(&mut self, mut n: usize) -> Result<(), NonZeroUsize> { if let Some(ref mut a) = self.a { - match a.advance_by(rem) { + n = match a.advance_by(n) { Ok(()) => return Ok(()), - Err(k) => rem -= k, - } + Err(k) => k.get(), + }; self.a = None; } if let Some(ref mut b) = self.b { - match b.advance_by(rem) { - Ok(()) => return Ok(()), - Err(k) => rem -= k, - } + return b.advance_by(n); // we don't fuse the second iterator } - if rem == 0 { Ok(()) } else { Err(n - rem) } + NonZeroUsize::new(n).map_or(Ok(()), Err) } #[inline] fn nth(&mut self, mut n: usize) -> Option<Self::Item> { if let Some(ref mut a) = self.a { - match a.advance_by(n) { + n = match a.advance_by(n) { Ok(()) => match a.next() { - None => n = 0, + None => 0, x => return x, }, - Err(k) => n -= k, - } + Err(k) => k.get(), + }; self.a = None; } @@ -186,38 +182,33 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { - let mut rem = n; - + fn advance_back_by(&mut self, mut n: usize) -> Result<(), NonZeroUsize> { if let Some(ref mut b) = self.b { - match b.advance_back_by(rem) { + n = match b.advance_back_by(n) { Ok(()) => return Ok(()), - Err(k) => rem -= k, - } + Err(k) => k.get(), + }; self.b = None; } if let Some(ref mut a) = self.a { - match a.advance_back_by(rem) { - Ok(()) => return Ok(()), - Err(k) => rem -= k, - } + return a.advance_back_by(n); // we don't fuse the second iterator } - if rem == 0 { Ok(()) } else { Err(n - rem) } + NonZeroUsize::new(n).map_or(Ok(()), Err) } #[inline] fn nth_back(&mut self, mut n: usize) -> Option<Self::Item> { if let Some(ref mut b) = self.b { - match b.advance_back_by(n) { + n = match b.advance_back_by(n) { Ok(()) => match b.next_back() { - None => n = 0, + None => 0, x => return x, }, - Err(k) => n -= k, - } + Err(k) => k.get(), + }; self.b = None; } diff --git a/library/core/src/iter/adapters/copied.rs b/library/core/src/iter/adapters/copied.rs index a076ab925e3..2289025d0a7 100644 --- a/library/core/src/iter/adapters/copied.rs +++ b/library/core/src/iter/adapters/copied.rs @@ -4,6 +4,7 @@ use crate::iter::adapters::{ use crate::iter::{FusedIterator, TrustedLen}; use crate::mem::MaybeUninit; use crate::mem::SizedTypeProperties; +use crate::num::NonZeroUsize; use crate::ops::Try; use crate::{array, ptr}; @@ -89,7 +90,7 @@ where } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.it.advance_by(n) } @@ -130,7 +131,7 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.it.advance_back_by(n) } } diff --git a/library/core/src/iter/adapters/cycle.rs b/library/core/src/iter/adapters/cycle.rs index 02b5939072e..51bd09b6eff 100644 --- a/library/core/src/iter/adapters/cycle.rs +++ b/library/core/src/iter/adapters/cycle.rs @@ -1,3 +1,4 @@ +use crate::num::NonZeroUsize; use crate::{iter::FusedIterator, ops::Try}; /// An iterator that repeats endlessly. @@ -81,23 +82,22 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - let mut rem = n; - match self.iter.advance_by(rem) { - ret @ Ok(_) => return ret, - Err(advanced) => rem -= advanced, - } + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { + let mut n = match self.iter.advance_by(n) { + Ok(()) => return Ok(()), + Err(rem) => rem.get(), + }; - while rem > 0 { + while n > 0 { self.iter = self.orig.clone(); - match self.iter.advance_by(rem) { - ret @ Ok(_) => return ret, - Err(0) => return Err(n - rem), - Err(advanced) => rem -= advanced, - } + n = match self.iter.advance_by(n) { + Ok(()) => return Ok(()), + e @ Err(rem) if rem.get() == n => return e, + Err(rem) => rem.get(), + }; } - Ok(()) + NonZeroUsize::new(n).map_or(Ok(()), Err) } // No `fold` override, because `fold` doesn't make much sense for `Cycle`, diff --git a/library/core/src/iter/adapters/enumerate.rs b/library/core/src/iter/adapters/enumerate.rs index 8c32a35a12f..479ea6d83c7 100644 --- a/library/core/src/iter/adapters/enumerate.rs +++ b/library/core/src/iter/adapters/enumerate.rs @@ -2,6 +2,7 @@ use crate::iter::adapters::{ zip::try_get_unchecked, SourceIter, TrustedRandomAccess, TrustedRandomAccessNoCoerce, }; use crate::iter::{FusedIterator, InPlaceIterable, TrustedLen}; +use crate::num::NonZeroUsize; use crate::ops::Try; /// An iterator that yields the current count and the element during iteration. @@ -114,17 +115,14 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - match self.iter.advance_by(n) { - ret @ Ok(_) => { - self.count += n; - ret - } - ret @ Err(advanced) => { - self.count += advanced; - ret - } - } + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { + let remaining = self.iter.advance_by(n); + let advanced = match remaining { + Ok(()) => n, + Err(rem) => n - rem.get(), + }; + self.count += advanced; + remaining } #[rustc_inherit_overflow_checks] @@ -208,7 +206,7 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // we do not need to update the count since that only tallies the number of items // consumed from the front. consuming items from the back can never reduce that. self.iter.advance_back_by(n) diff --git a/library/core/src/iter/adapters/flatten.rs b/library/core/src/iter/adapters/flatten.rs index e4020c45f71..e0308e3360f 100644 --- a/library/core/src/iter/adapters/flatten.rs +++ b/library/core/src/iter/adapters/flatten.rs @@ -1,5 +1,6 @@ use crate::fmt; use crate::iter::{DoubleEndedIterator, Fuse, FusedIterator, Iterator, Map, TrustedLen}; +use crate::num::NonZeroUsize; use crate::ops::{ControlFlow, Try}; /// An iterator that maps each element to an iterator, and yields the elements @@ -75,7 +76,7 @@ where } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.inner.advance_by(n) } @@ -120,7 +121,7 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.inner.advance_back_by(n) } } @@ -236,7 +237,7 @@ where } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.inner.advance_by(n) } @@ -281,7 +282,7 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.inner.advance_back_by(n) } } @@ -552,18 +553,18 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { #[inline] #[rustc_inherit_overflow_checks] fn advance<U: Iterator>(n: usize, iter: &mut U) -> ControlFlow<(), usize> { match iter.advance_by(n) { Ok(()) => ControlFlow::Break(()), - Err(advanced) => ControlFlow::Continue(n - advanced), + Err(remaining) => ControlFlow::Continue(remaining.get()), } } match self.iter_try_fold(n, advance) { - ControlFlow::Continue(remaining) if remaining > 0 => Err(n - remaining), + ControlFlow::Continue(remaining) => NonZeroUsize::new(remaining).map_or(Ok(()), Err), _ => Ok(()), } } @@ -642,18 +643,18 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { #[inline] #[rustc_inherit_overflow_checks] fn advance<U: DoubleEndedIterator>(n: usize, iter: &mut U) -> ControlFlow<(), usize> { match iter.advance_back_by(n) { Ok(()) => ControlFlow::Break(()), - Err(advanced) => ControlFlow::Continue(n - advanced), + Err(remaining) => ControlFlow::Continue(remaining.get()), } } match self.iter_try_rfold(n, advance) { - ControlFlow::Continue(remaining) if remaining > 0 => Err(n - remaining), + ControlFlow::Continue(remaining) => NonZeroUsize::new(remaining).map_or(Ok(()), Err), _ => Ok(()), } } diff --git a/library/core/src/iter/adapters/rev.rs b/library/core/src/iter/adapters/rev.rs index 8ae6d96fde4..1d882087f69 100644 --- a/library/core/src/iter/adapters/rev.rs +++ b/library/core/src/iter/adapters/rev.rs @@ -1,4 +1,5 @@ use crate::iter::{FusedIterator, TrustedLen}; +use crate::num::NonZeroUsize; use crate::ops::Try; /// A double-ended iterator with the direction inverted. @@ -38,7 +39,7 @@ where } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.iter.advance_back_by(n) } @@ -83,7 +84,7 @@ where } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.iter.advance_by(n) } diff --git a/library/core/src/iter/adapters/skip.rs b/library/core/src/iter/adapters/skip.rs index c6334880db5..306338bc7cc 100644 --- a/library/core/src/iter/adapters/skip.rs +++ b/library/core/src/iter/adapters/skip.rs @@ -1,5 +1,6 @@ use crate::intrinsics::unlikely; use crate::iter::{adapters::SourceIter, FusedIterator, InPlaceIterable}; +use crate::num::NonZeroUsize; use crate::ops::{ControlFlow, Try}; /// An iterator that skips over `n` elements of `iter`. @@ -128,34 +129,27 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - let mut rem = n; - let step_one = self.n.saturating_add(rem); - - match self.iter.advance_by(step_one) { - Ok(_) => { - rem -= step_one - self.n; - self.n = 0; - } - Err(advanced) => { - let advanced_without_skip = advanced.saturating_sub(self.n); - self.n = self.n.saturating_sub(advanced); - return if n == 0 { Ok(()) } else { Err(advanced_without_skip) }; - } - } + fn advance_by(&mut self, mut n: usize) -> Result<(), NonZeroUsize> { + let skip_inner = self.n; + let skip_and_advance = skip_inner.saturating_add(n); - // step_one calculation may have saturated - if unlikely(rem > 0) { - return match self.iter.advance_by(rem) { - ret @ Ok(_) => ret, - Err(advanced) => { - rem -= advanced; - Err(n - rem) - } - }; + let remainder = match self.iter.advance_by(skip_and_advance) { + Ok(()) => 0, + Err(n) => n.get(), + }; + let advanced_inner = skip_and_advance - remainder; + n -= advanced_inner.saturating_sub(skip_inner); + self.n = self.n.saturating_sub(advanced_inner); + + // skip_and_advance may have saturated + if unlikely(remainder == 0 && n > 0) { + n = match self.iter.advance_by(n) { + Ok(()) => 0, + Err(n) => n.get(), + } } - Ok(()) + NonZeroUsize::new(n).map_or(Ok(()), Err) } } @@ -209,13 +203,11 @@ where impl_fold_via_try_fold! { rfold -> try_rfold } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { let min = crate::cmp::min(self.len(), n); - return match self.iter.advance_back_by(min) { - ret @ Ok(_) if n <= min => ret, - Ok(_) => Err(min), - _ => panic!("ExactSizeIterator contract violation"), - }; + let rem = self.iter.advance_back_by(min); + assert!(rem.is_ok(), "ExactSizeIterator contract violation"); + NonZeroUsize::new(n - min).map_or(Ok(()), Err) } } diff --git a/library/core/src/iter/adapters/take.rs b/library/core/src/iter/adapters/take.rs index d947c7b0e30..ce18bffe714 100644 --- a/library/core/src/iter/adapters/take.rs +++ b/library/core/src/iter/adapters/take.rs @@ -1,5 +1,6 @@ use crate::cmp; use crate::iter::{adapters::SourceIter, FusedIterator, InPlaceIterable, TrustedLen}; +use crate::num::NonZeroUsize; use crate::ops::{ControlFlow, Try}; /// An iterator that only iterates over the first `n` iterations of `iter`. @@ -121,18 +122,15 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { let min = self.n.min(n); - match self.iter.advance_by(min) { - Ok(_) => { - self.n -= min; - if min < n { Err(min) } else { Ok(()) } - } - ret @ Err(advanced) => { - self.n -= advanced; - ret - } - } + let rem = match self.iter.advance_by(min) { + Ok(()) => 0, + Err(rem) => rem.get(), + }; + let advanced = min - rem; + self.n -= advanced; + NonZeroUsize::new(n - advanced).map_or(Ok(()), Err) } } @@ -223,7 +221,7 @@ where #[inline] #[rustc_inherit_overflow_checks] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // The amount by which the inner iterator needs to be shortened for it to be // at most as long as the take() amount. let trim_inner = self.iter.len().saturating_sub(self.n); @@ -232,12 +230,14 @@ where // about having to advance more than usize::MAX here. let advance_by = trim_inner.saturating_add(n); - let advanced = match self.iter.advance_back_by(advance_by) { - Ok(_) => advance_by - trim_inner, - Err(advanced) => advanced - trim_inner, + let remainder = match self.iter.advance_back_by(advance_by) { + Ok(()) => 0, + Err(rem) => rem.get(), }; - self.n -= advanced; - return if advanced < n { Err(advanced) } else { Ok(()) }; + let advanced_by_inner = advance_by - remainder; + let advanced_by = advanced_by_inner - trim_inner; + self.n -= advanced_by; + NonZeroUsize::new(n - advanced_by).map_or(Ok(()), Err) } } diff --git a/library/core/src/iter/range.rs b/library/core/src/iter/range.rs index f19636fba5d..1cd71193bd7 100644 --- a/library/core/src/iter/range.rs +++ b/library/core/src/iter/range.rs @@ -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) -> Result<(), 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) -> Result<(), 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) -> Result<(), 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"); - if taken < n { Err(taken) } else { Ok(()) } + 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) -> Result<(), 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"); - if taken < n { Err(taken) } else { Ok(()) } + 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) -> Result<(), 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) }; - if taken < n { Err(taken) } else { Ok(()) } + 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) -> Result<(), 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) }; - if taken < n { Err(taken) } else { Ok(()) } + 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) -> Result<(), 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) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.spec_advance_back_by(n) } } diff --git a/library/core/src/iter/sources/repeat.rs b/library/core/src/iter/sources/repeat.rs index 733142ed011..67051f6e97b 100644 --- a/library/core/src/iter/sources/repeat.rs +++ b/library/core/src/iter/sources/repeat.rs @@ -1,4 +1,5 @@ use crate::iter::{FusedIterator, TrustedLen}; +use crate::num::NonZeroUsize; /// Creates a new iterator that endlessly repeats a single element. /// @@ -80,7 +81,7 @@ impl<A: Clone> Iterator for Repeat<A> { } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // Advancing an infinite iterator of a single element is a no-op. let _ = n; Ok(()) @@ -109,7 +110,7 @@ impl<A: Clone> DoubleEndedIterator for Repeat<A> { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { // Advancing an infinite iterator of a single element is a no-op. let _ = n; Ok(()) diff --git a/library/core/src/iter/sources/repeat_n.rs b/library/core/src/iter/sources/repeat_n.rs index dc61d6065b8..0b0445850bf 100644 --- a/library/core/src/iter/sources/repeat_n.rs +++ b/library/core/src/iter/sources/repeat_n.rs @@ -1,5 +1,6 @@ use crate::iter::{FusedIterator, TrustedLen}; use crate::mem::ManuallyDrop; +use crate::num::NonZeroUsize; /// Creates a new iterator that repeats a single element a given number of times. /// @@ -137,7 +138,7 @@ impl<A: Clone> Iterator for RepeatN<A> { } #[inline] - fn advance_by(&mut self, skip: usize) -> Result<(), usize> { + fn advance_by(&mut self, skip: usize) -> Result<(), NonZeroUsize> { let len = self.count; if skip >= len { @@ -145,7 +146,8 @@ impl<A: Clone> Iterator for RepeatN<A> { } if skip > len { - Err(len) + // SAFETY: we just checked that the difference is positive + Err(unsafe { NonZeroUsize::new_unchecked(skip - len) }) } else { self.count = len - skip; Ok(()) @@ -178,7 +180,7 @@ impl<A: Clone> DoubleEndedIterator for RepeatN<A> { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { self.advance_by(n) } diff --git a/library/core/src/iter/traits/double_ended.rs b/library/core/src/iter/traits/double_ended.rs index 7a10dea500a..d82ecb698dd 100644 --- a/library/core/src/iter/traits/double_ended.rs +++ b/library/core/src/iter/traits/double_ended.rs @@ -1,4 +1,5 @@ use crate::marker::Destruct; +use crate::num::NonZeroUsize; use crate::ops::{ControlFlow, Try}; /// An iterator able to yield elements from both ends. @@ -100,10 +101,11 @@ pub trait DoubleEndedIterator: Iterator { /// eagerly skip `n` elements starting from the back by calling [`next_back`] up /// to `n` times until [`None`] is encountered. /// - /// `advance_back_by(n)` will return [`Ok(())`] if the iterator successfully advances by - /// `n` elements, or [`Err(k)`] if [`None`] is encountered, where `k` is the number of - /// elements the iterator is advanced by before running out of elements (i.e. the length - /// of the iterator). Note that `k` is always less than `n`. + /// `advance_back_by(n)` will return `Ok(())` if the iterator successfully advances by + /// `n` elements, or a `Err(NonZeroUsize)` with value `k` if [`None`] is encountered, where `k` + /// is remaining number of steps that could not be advanced because the iterator ran out. + /// If `self` is empty and `n` is non-zero, then this returns `Err(n)`. + /// Otherwise, `k` is always less than `n`. /// /// Calling `advance_back_by(0)` can do meaningful work, for example [`Flatten`] can advance its /// outer iterator until it finds an inner iterator that is not empty, which then often @@ -120,25 +122,29 @@ pub trait DoubleEndedIterator: Iterator { /// ``` /// #![feature(iter_advance_by)] /// + /// use std::num::NonZeroUsize; /// let a = [3, 4, 5, 6]; /// let mut iter = a.iter(); /// /// assert_eq!(iter.advance_back_by(2), Ok(())); /// assert_eq!(iter.next_back(), Some(&4)); /// assert_eq!(iter.advance_back_by(0), Ok(())); - /// assert_eq!(iter.advance_back_by(100), Err(1)); // only `&3` was skipped + /// assert_eq!(iter.advance_back_by(100), Err(NonZeroUsize::new(99).unwrap())); // only `&3` was skipped /// ``` /// /// [`Ok(())`]: Ok /// [`Err(k)`]: Err #[inline] #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> where Self::Item: ~const Destruct, { for i in 0..n { - self.next_back().ok_or(i)?; + if self.next_back().is_none() { + // SAFETY: `i` is always less than `n`. + return Err(unsafe { NonZeroUsize::new_unchecked(n - i) }); + } } Ok(()) } @@ -188,7 +194,9 @@ pub trait DoubleEndedIterator: Iterator { #[stable(feature = "iter_nth_back", since = "1.37.0")] #[rustc_do_not_const_check] fn nth_back(&mut self, n: usize) -> Option<Self::Item> { - self.advance_back_by(n).ok()?; + if self.advance_back_by(n).is_err() { + return None; + } self.next_back() } @@ -374,7 +382,7 @@ impl<'a, I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for &'a mut I { fn next_back(&mut self) -> Option<I::Item> { (**self).next_back() } - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { (**self).advance_back_by(n) } fn nth_back(&mut self, n: usize) -> Option<I::Item> { diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs index 16c9f668b8e..080330fa41e 100644 --- a/library/core/src/iter/traits/iterator.rs +++ b/library/core/src/iter/traits/iterator.rs @@ -1,6 +1,7 @@ use crate::array; use crate::cmp::{self, Ordering}; use crate::marker::Destruct; +use crate::num::NonZeroUsize; use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, Residual, Try}; use super::super::try_process; @@ -308,10 +309,11 @@ pub trait Iterator { /// This method will eagerly skip `n` elements by calling [`next`] up to `n` /// times until [`None`] is encountered. /// - /// `advance_by(n)` will return [`Ok(())`][Ok] if the iterator successfully advances by - /// `n` elements, or [`Err(k)`][Err] if [`None`] is encountered, where `k` is the number - /// of elements the iterator is advanced by before running out of elements (i.e. the - /// length of the iterator). Note that `k` is always less than `n`. + /// `advance_by(n)` will return `Ok(())` if the iterator successfully advances by + /// `n` elements, or a `Err(NonZeroUsize)` with value `k` if [`None`] is encountered, + /// where `k` is remaining number of steps that could not be advanced because the iterator ran out. + /// If `self` is empty and `n` is non-zero, then this returns `Err(n)`. + /// Otherwise, `k` is always less than `n`. /// /// Calling `advance_by(0)` can do meaningful work, for example [`Flatten`] /// can advance its outer iterator until it finds an inner iterator that is not empty, which @@ -327,22 +329,26 @@ pub trait Iterator { /// ``` /// #![feature(iter_advance_by)] /// + /// use std::num::NonZeroUsize; /// let a = [1, 2, 3, 4]; /// let mut iter = a.iter(); /// /// assert_eq!(iter.advance_by(2), Ok(())); /// assert_eq!(iter.next(), Some(&3)); /// assert_eq!(iter.advance_by(0), Ok(())); - /// assert_eq!(iter.advance_by(100), Err(1)); // only `&4` was skipped + /// assert_eq!(iter.advance_by(100), Err(NonZeroUsize::new(99).unwrap())); // only `&4` was skipped /// ``` #[inline] #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")] - fn advance_by(&mut self, n: usize) -> Result<(), usize> + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> where Self::Item: ~const Destruct, { for i in 0..n { - self.next().ok_or(i)?; + if self.next().is_none() { + // SAFETY: `i` is always less than `n`. + return Err(unsafe { NonZeroUsize::new_unchecked(n - i) }); + } } Ok(()) } @@ -4013,7 +4019,7 @@ impl<I: Iterator + ?Sized> Iterator for &mut I { fn size_hint(&self) -> (usize, Option<usize>) { (**self).size_hint() } - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { (**self).advance_by(n) } fn nth(&mut self, n: usize) -> Option<Self::Item> { diff --git a/library/core/src/ops/index_range.rs b/library/core/src/ops/index_range.rs index 3e06776d2c6..265022a394e 100644 --- a/library/core/src/ops/index_range.rs +++ b/library/core/src/ops/index_range.rs @@ -1,5 +1,6 @@ use crate::intrinsics::{assert_unsafe_precondition, unchecked_add, unchecked_sub}; use crate::iter::{FusedIterator, TrustedLen}; +use crate::num::NonZeroUsize; /// Like a `Range<usize>`, but with a safety invariant that `start <= end`. /// @@ -132,10 +133,9 @@ impl Iterator for IndexRange { } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - let original_len = self.len(); - self.take_prefix(n); - if n > original_len { Err(original_len) } else { Ok(()) } + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { + let taken = self.take_prefix(n); + NonZeroUsize::new(n - taken.len()).map_or(Ok(()), Err) } } @@ -151,10 +151,9 @@ impl DoubleEndedIterator for IndexRange { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { - let original_len = self.len(); - self.take_suffix(n); - if n > original_len { Err(original_len) } else { Ok(()) } + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { + let taken = self.take_suffix(n); + NonZeroUsize::new(n - taken.len()).map_or(Ok(()), Err) } } diff --git a/library/core/src/slice/iter/macros.rs b/library/core/src/slice/iter/macros.rs index a800da546b4..b73e35f1e91 100644 --- a/library/core/src/slice/iter/macros.rs +++ b/library/core/src/slice/iter/macros.rs @@ -176,11 +176,11 @@ macro_rules! iterator { } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { let advance = cmp::min(len!(self), n); // SAFETY: By construction, `advance` does not exceed `self.len()`. unsafe { self.post_inc_start(advance) }; - if advance == n { Ok(()) } else { Err(advance) } + NonZeroUsize::new(n - advance).map_or(Ok(()), Err) } #[inline] @@ -371,11 +371,11 @@ macro_rules! iterator { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { let advance = cmp::min(len!(self), n); // SAFETY: By construction, `advance` does not exceed `self.len()`. unsafe { self.pre_dec_end(advance) }; - if advance == n { Ok(()) } else { Err(advance) } + NonZeroUsize::new(n - advance).map_or(Ok(()), Err) } } diff --git a/library/core/tests/array.rs b/library/core/tests/array.rs index 5327e4f8139..0869644c040 100644 --- a/library/core/tests/array.rs +++ b/library/core/tests/array.rs @@ -1,5 +1,6 @@ -use core::array; +use core::{array, assert_eq}; use core::convert::TryFrom; +use core::num::NonZeroUsize; use core::sync::atomic::{AtomicUsize, Ordering}; #[test] @@ -557,7 +558,7 @@ fn array_intoiter_advance_by() { assert_eq!(counter.get(), 13); let r = it.advance_by(123456); - assert_eq!(r, Err(87)); + assert_eq!(r, Err(NonZeroUsize::new(123456 - 87).unwrap())); assert_eq!(it.len(), 0); assert_eq!(counter.get(), 100); @@ -567,7 +568,7 @@ fn array_intoiter_advance_by() { assert_eq!(counter.get(), 100); let r = it.advance_by(10); - assert_eq!(r, Err(0)); + assert_eq!(r, Err(NonZeroUsize::new(10).unwrap())); assert_eq!(it.len(), 0); assert_eq!(counter.get(), 100); } @@ -610,7 +611,7 @@ fn array_intoiter_advance_back_by() { assert_eq!(counter.get(), 13); let r = it.advance_back_by(123456); - assert_eq!(r, Err(87)); + assert_eq!(r, Err(NonZeroUsize::new(123456 - 87).unwrap())); assert_eq!(it.len(), 0); assert_eq!(counter.get(), 100); @@ -620,7 +621,7 @@ fn array_intoiter_advance_back_by() { assert_eq!(counter.get(), 100); let r = it.advance_back_by(10); - assert_eq!(r, Err(0)); + assert_eq!(r, Err(NonZeroUsize::new(10).unwrap())); assert_eq!(it.len(), 0); assert_eq!(counter.get(), 100); } @@ -679,8 +680,8 @@ fn array_into_iter_fold() { let a = [1, 2, 3, 4, 5, 6]; let mut it = a.into_iter(); - it.advance_by(1).unwrap(); - it.advance_back_by(2).unwrap(); + assert_eq!(it.advance_by(1), Ok(())); + assert_eq!(it.advance_back_by(2), Ok(())); let s = it.fold(10, |a, b| 10 * a + b); assert_eq!(s, 10234); } @@ -695,8 +696,8 @@ fn array_into_iter_rfold() { let a = [1, 2, 3, 4, 5, 6]; let mut it = a.into_iter(); - it.advance_by(1).unwrap(); - it.advance_back_by(2).unwrap(); + assert_eq!(it.advance_by(1), Ok(())); + assert_eq!(it.advance_back_by(2), Ok(())); let s = it.rfold(10, |a, b| 10 * a + b); assert_eq!(s, 10432); } diff --git a/library/core/tests/iter/adapters/chain.rs b/library/core/tests/iter/adapters/chain.rs index f419f9cec12..175a1b638e1 100644 --- a/library/core/tests/iter/adapters/chain.rs +++ b/library/core/tests/iter/adapters/chain.rs @@ -1,5 +1,6 @@ use super::*; use core::iter::*; +use core::num::NonZeroUsize; #[test] fn test_iterator_chain() { @@ -31,28 +32,28 @@ fn test_iterator_chain_advance_by() { for i in 0..xs.len() { let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); - iter.advance_by(i).unwrap(); + assert_eq!(iter.advance_by(i), Ok(())); assert_eq!(iter.next(), Some(&xs[i])); - assert_eq!(iter.advance_by(100), Err(len - i - 1)); - iter.advance_by(0).unwrap(); + assert_eq!(iter.advance_by(100), Err(NonZeroUsize::new(100 - (len - i - 1)).unwrap())); + assert_eq!(iter.advance_by(0), Ok(())); } for i in 0..ys.len() { let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); - iter.advance_by(xs.len() + i).unwrap(); + assert_eq!(iter.advance_by(xs.len() + i), Ok(())); assert_eq!(iter.next(), Some(&ys[i])); - assert_eq!(iter.advance_by(100), Err(ys.len() - i - 1)); - iter.advance_by(0).unwrap(); + assert_eq!(iter.advance_by(100), Err(NonZeroUsize::new(100 - (ys.len() - i - 1)).unwrap())); + assert_eq!(iter.advance_by(0), Ok(())); } let mut iter = xs.iter().chain(ys); - iter.advance_by(len).unwrap(); + assert_eq!(iter.advance_by(len), Ok(())); assert_eq!(iter.next(), None); - iter.advance_by(0).unwrap(); + assert_eq!(iter.advance_by(0), Ok(())); let mut iter = xs.iter().chain(ys); - assert_eq!(iter.advance_by(len + 1), Err(len)); - iter.advance_by(0).unwrap(); + assert_eq!(iter.advance_by(len + 1), Err(NonZeroUsize::new(1).unwrap())); + assert_eq!(iter.advance_by(0), Ok(())); } test_chain(&[], &[]); @@ -68,28 +69,28 @@ fn test_iterator_chain_advance_back_by() { for i in 0..ys.len() { let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); - iter.advance_back_by(i).unwrap(); + assert_eq!(iter.advance_back_by(i), Ok(())); assert_eq!(iter.next_back(), Some(&ys[ys.len() - i - 1])); - assert_eq!(iter.advance_back_by(100), Err(len - i - 1)); - iter.advance_back_by(0).unwrap(); + assert_eq!(iter.advance_back_by(100), Err(NonZeroUsize::new(100 - (len - i - 1)).unwrap())); + assert_eq!(iter.advance_back_by(0), Ok(())); } for i in 0..xs.len() { let mut iter = Unfuse::new(xs).chain(Unfuse::new(ys)); - iter.advance_back_by(ys.len() + i).unwrap(); + assert_eq!(iter.advance_back_by(ys.len() + i), Ok(())); assert_eq!(iter.next_back(), Some(&xs[xs.len() - i - 1])); - assert_eq!(iter.advance_back_by(100), Err(xs.len() - i - 1)); - iter.advance_back_by(0).unwrap(); + assert_eq!(iter.advance_back_by(100), Err(NonZeroUsize::new(100 - (xs.len() - i - 1)).unwrap())); + assert_eq!(iter.advance_back_by(0), Ok(())); } let mut iter = xs.iter().chain(ys); - iter.advance_back_by(len).unwrap(); + assert_eq!(iter.advance_back_by(len), Ok(())); assert_eq!(iter.next_back(), None); - iter.advance_back_by(0).unwrap(); + assert_eq!(iter.advance_back_by(0), Ok(())); let mut iter = xs.iter().chain(ys); - assert_eq!(iter.advance_back_by(len + 1), Err(len)); - iter.advance_back_by(0).unwrap(); + assert_eq!(iter.advance_back_by(len + 1), Err(NonZeroUsize::new(1).unwrap())); + assert_eq!(iter.advance_back_by(0), Ok(())); } test_chain(&[], &[]); diff --git a/library/core/tests/iter/adapters/enumerate.rs b/library/core/tests/iter/adapters/enumerate.rs index 0e603387847..ff57973a62a 100644 --- a/library/core/tests/iter/adapters/enumerate.rs +++ b/library/core/tests/iter/adapters/enumerate.rs @@ -1,4 +1,5 @@ use core::iter::*; +use core::num::NonZeroUsize; #[test] fn test_iterator_enumerate() { @@ -56,6 +57,20 @@ fn test_iterator_enumerate_count() { } #[test] +fn test_iterator_enumerate_advance_by() { + let xs = [0, 1, 2, 3, 4, 5]; + let mut it = xs.iter().enumerate(); + assert_eq!(it.advance_by(0), Ok(())); + assert_eq!(it.next(), Some((0, &0))); + assert_eq!(it.advance_by(1), Ok(())); + assert_eq!(it.next(), Some((2, &2))); + assert_eq!(it.advance_by(2), Ok(())); + assert_eq!(it.next(), Some((5, &5))); + assert_eq!(it.advance_by(1), Err(NonZeroUsize::new(1).unwrap())); + assert_eq!(it.next(), None); +} + +#[test] fn test_iterator_enumerate_fold() { let xs = [0, 1, 2, 3, 4, 5]; let mut it = xs.iter().enumerate(); diff --git a/library/core/tests/iter/adapters/flatten.rs b/library/core/tests/iter/adapters/flatten.rs index 690fd0c2197..91809c9e5fd 100644 --- a/library/core/tests/iter/adapters/flatten.rs +++ b/library/core/tests/iter/adapters/flatten.rs @@ -1,5 +1,7 @@ +use core::assert_eq; use super::*; use core::iter::*; +use core::num::NonZeroUsize; #[test] fn test_iterator_flatten() { @@ -61,19 +63,19 @@ fn test_flatten_try_folds() { fn test_flatten_advance_by() { let mut it = once(0..10).chain(once(10..30)).chain(once(30..40)).flatten(); - it.advance_by(5).unwrap(); + assert_eq!(it.advance_by(5), Ok(())); assert_eq!(it.next(), Some(5)); - it.advance_by(9).unwrap(); + assert_eq!(it.advance_by(9), Ok(())); assert_eq!(it.next(), Some(15)); - it.advance_back_by(4).unwrap(); + assert_eq!(it.advance_back_by(4), Ok(())); assert_eq!(it.next_back(), Some(35)); - it.advance_back_by(9).unwrap(); + assert_eq!(it.advance_back_by(9), Ok(())); assert_eq!(it.next_back(), Some(25)); - assert_eq!(it.advance_by(usize::MAX), Err(9)); - assert_eq!(it.advance_back_by(usize::MAX), Err(0)); - it.advance_by(0).unwrap(); - it.advance_back_by(0).unwrap(); + assert_eq!(it.advance_by(usize::MAX), Err(NonZeroUsize::new(usize::MAX - 9).unwrap())); + assert_eq!(it.advance_back_by(usize::MAX), Err(NonZeroUsize::new(usize::MAX).unwrap())); + assert_eq!(it.advance_by(0), Ok(())); + assert_eq!(it.advance_back_by(0), Ok(())); assert_eq!(it.size_hint(), (0, Some(0))); } @@ -174,19 +176,19 @@ fn test_flatten_count() { let mut it = once(0..10).chain(once(10..30)).chain(once(30..40)).flatten(); assert_eq!(it.clone().count(), 40); - it.advance_by(5).unwrap(); + assert_eq!(it.advance_by(5), Ok(())); assert_eq!(it.clone().count(), 35); - it.advance_back_by(5).unwrap(); + assert_eq!(it.advance_back_by(5), Ok(())); assert_eq!(it.clone().count(), 30); - it.advance_by(10).unwrap(); + assert_eq!(it.advance_by(10), Ok(())); assert_eq!(it.clone().count(), 20); - it.advance_back_by(8).unwrap(); + assert_eq!(it.advance_back_by(8), Ok(())); assert_eq!(it.clone().count(), 12); - it.advance_by(4).unwrap(); + assert_eq!(it.advance_by(4), Ok(())); assert_eq!(it.clone().count(), 8); - it.advance_back_by(5).unwrap(); + assert_eq!(it.advance_back_by(5), Ok(())); assert_eq!(it.clone().count(), 3); - it.advance_by(3).unwrap(); + assert_eq!(it.advance_by(3), Ok(())); assert_eq!(it.clone().count(), 0); } @@ -195,18 +197,18 @@ fn test_flatten_last() { let mut it = once(0..10).chain(once(10..30)).chain(once(30..40)).flatten(); assert_eq!(it.clone().last(), Some(39)); - it.advance_by(5).unwrap(); // 5..40 + assert_eq!(it.advance_by(5), Ok(())); // 5..40 assert_eq!(it.clone().last(), Some(39)); - it.advance_back_by(5).unwrap(); // 5..35 + assert_eq!(it.advance_back_by(5), Ok(())); // 5..35 assert_eq!(it.clone().last(), Some(34)); - it.advance_by(10).unwrap(); // 15..35 + assert_eq!(it.advance_by(10), Ok(())); // 15..35 assert_eq!(it.clone().last(), Some(34)); - it.advance_back_by(8).unwrap(); // 15..27 + assert_eq!(it.advance_back_by(8), Ok(())); // 15..27 assert_eq!(it.clone().last(), Some(26)); - it.advance_by(4).unwrap(); // 19..27 + assert_eq!(it.advance_by(4), Ok(())); // 19..27 assert_eq!(it.clone().last(), Some(26)); - it.advance_back_by(5).unwrap(); // 19..22 + assert_eq!(it.advance_back_by(5), Ok(())); // 19..22 assert_eq!(it.clone().last(), Some(21)); - it.advance_by(3).unwrap(); // 22..22 + assert_eq!(it.advance_by(3), Ok(())); // 22..22 assert_eq!(it.clone().last(), None); } diff --git a/library/core/tests/iter/adapters/skip.rs b/library/core/tests/iter/adapters/skip.rs index 754641834e8..e3e88a84fad 100644 --- a/library/core/tests/iter/adapters/skip.rs +++ b/library/core/tests/iter/adapters/skip.rs @@ -1,4 +1,5 @@ use core::iter::*; +use core::num::NonZeroUsize; use super::Unfuse; @@ -74,11 +75,14 @@ fn test_iterator_skip_nth() { #[test] fn test_skip_advance_by() { assert_eq!((0..0).skip(10).advance_by(0), Ok(())); - assert_eq!((0..0).skip(10).advance_by(1), Err(0)); - assert_eq!((0u128..(usize::MAX as u128) + 1).skip(usize::MAX).advance_by(usize::MAX), Err(1)); - assert_eq!((0u128..u128::MAX).skip(usize::MAX).advance_by(1), Ok(())); - - assert_eq!((0..2).skip(1).advance_back_by(10), Err(1)); + assert_eq!((0..0).skip(10).advance_by(1), Err(NonZeroUsize::new(1).unwrap())); + assert_eq!( + (0u128..(usize::MAX as u128) + 1).skip(usize::MAX - 10).advance_by(usize::MAX - 5), + Err(NonZeroUsize::new(usize::MAX - 16).unwrap()) + ); + assert_eq!((0u128..u128::MAX).skip(usize::MAX - 10).advance_by(20), Ok(())); + + assert_eq!((0..2).skip(1).advance_back_by(10), Err(NonZeroUsize::new(9).unwrap())); assert_eq!((0..0).skip(1).advance_back_by(0), Ok(())); } diff --git a/library/core/tests/iter/adapters/take.rs b/library/core/tests/iter/adapters/take.rs index 3e26b43a2ed..3cad47c06de 100644 --- a/library/core/tests/iter/adapters/take.rs +++ b/library/core/tests/iter/adapters/take.rs @@ -1,4 +1,5 @@ use core::iter::*; +use core::num::NonZeroUsize; #[test] fn test_iterator_take() { @@ -78,21 +79,21 @@ fn test_take_advance_by() { let mut take = (0..10).take(3); assert_eq!(take.advance_by(2), Ok(())); assert_eq!(take.next(), Some(2)); - assert_eq!(take.advance_by(1), Err(0)); + assert_eq!(take.advance_by(1), Err(NonZeroUsize::new(1).unwrap())); assert_eq!((0..0).take(10).advance_by(0), Ok(())); - assert_eq!((0..0).take(10).advance_by(1), Err(0)); - assert_eq!((0..10).take(4).advance_by(5), Err(4)); + assert_eq!((0..0).take(10).advance_by(1), Err(NonZeroUsize::new(1).unwrap())); + assert_eq!((0..10).take(4).advance_by(5), Err(NonZeroUsize::new(1).unwrap())); let mut take = (0..10).take(3); assert_eq!(take.advance_back_by(2), Ok(())); assert_eq!(take.next(), Some(0)); - assert_eq!(take.advance_back_by(1), Err(0)); + assert_eq!(take.advance_back_by(1), Err(NonZeroUsize::new(1).unwrap())); - assert_eq!((0..2).take(1).advance_back_by(10), Err(1)); - assert_eq!((0..0).take(1).advance_back_by(1), Err(0)); + assert_eq!((0..2).take(1).advance_back_by(10), Err(NonZeroUsize::new(9).unwrap())); + assert_eq!((0..0).take(1).advance_back_by(1), Err(NonZeroUsize::new(1).unwrap())); assert_eq!((0..0).take(1).advance_back_by(0), Ok(())); - assert_eq!((0..usize::MAX).take(100).advance_back_by(usize::MAX), Err(100)); + assert_eq!((0..usize::MAX).take(100).advance_back_by(usize::MAX), Err(NonZeroUsize::new(usize::MAX - 100).unwrap())); } #[test] diff --git a/library/core/tests/iter/range.rs b/library/core/tests/iter/range.rs index 0f91ffe2dfc..0a77ecddb84 100644 --- a/library/core/tests/iter/range.rs +++ b/library/core/tests/iter/range.rs @@ -1,3 +1,4 @@ +use core::num::NonZeroUsize; use super::*; #[test] @@ -287,25 +288,25 @@ fn test_range_step() { #[test] fn test_range_advance_by() { let mut r = 0..usize::MAX; - r.advance_by(0).unwrap(); - r.advance_back_by(0).unwrap(); + assert_eq!(Ok(()), r.advance_by(0)); + assert_eq!(Ok(()), r.advance_back_by(0)); assert_eq!(r.len(), usize::MAX); - r.advance_by(1).unwrap(); - r.advance_back_by(1).unwrap(); + assert_eq!(Ok(()), r.advance_by(1)); + assert_eq!(Ok(()), r.advance_back_by(1)); assert_eq!((r.start, r.end), (1, usize::MAX - 1)); - assert_eq!(r.advance_by(usize::MAX), Err(usize::MAX - 2)); + assert_eq!(Err(NonZeroUsize::new(2).unwrap()), r.advance_by(usize::MAX)); - r.advance_by(0).unwrap(); - r.advance_back_by(0).unwrap(); + assert_eq!(Ok(()), r.advance_by(0)); + assert_eq!(Ok(()), r.advance_back_by(0)); let mut r = 0u128..u128::MAX; - r.advance_by(usize::MAX).unwrap(); - r.advance_back_by(usize::MAX).unwrap(); + assert_eq!(Ok(()), r.advance_by(usize::MAX)); + assert_eq!(Ok(()), r.advance_back_by(usize::MAX)); assert_eq!((r.start, r.end), (0u128 + usize::MAX as u128, u128::MAX - usize::MAX as u128)); } diff --git a/library/core/tests/iter/traits/iterator.rs b/library/core/tests/iter/traits/iterator.rs index 62566a9502d..9eebfb1f1f3 100644 --- a/library/core/tests/iter/traits/iterator.rs +++ b/library/core/tests/iter/traits/iterator.rs @@ -1,3 +1,5 @@ +use core::num::NonZeroUsize; + /// A wrapper struct that implements `Eq` and `Ord` based on the wrapped /// integer modulo 3. Used to test that `Iterator::max` and `Iterator::min` /// return the correct element if some of them are equal. @@ -150,11 +152,11 @@ fn test_iterator_advance_by() { let mut iter = v.iter(); assert_eq!(iter.advance_by(i), Ok(())); assert_eq!(iter.next().unwrap(), &v[i]); - assert_eq!(iter.advance_by(100), Err(v.len() - 1 - i)); + assert_eq!(iter.advance_by(100), Err(NonZeroUsize::new(100 - (v.len() - 1 - i)).unwrap())); } assert_eq!(v.iter().advance_by(v.len()), Ok(())); - assert_eq!(v.iter().advance_by(100), Err(v.len())); + assert_eq!(v.iter().advance_by(100), Err(NonZeroUsize::new(100 - v.len()).unwrap())); } #[test] @@ -165,11 +167,11 @@ fn test_iterator_advance_back_by() { let mut iter = v.iter(); assert_eq!(iter.advance_back_by(i), Ok(())); assert_eq!(iter.next_back().unwrap(), &v[v.len() - 1 - i]); - assert_eq!(iter.advance_back_by(100), Err(v.len() - 1 - i)); + assert_eq!(iter.advance_back_by(100), Err(NonZeroUsize::new(100 - (v.len() - 1 - i)).unwrap())); } assert_eq!(v.iter().advance_back_by(v.len()), Ok(())); - assert_eq!(v.iter().advance_back_by(100), Err(v.len())); + assert_eq!(v.iter().advance_back_by(100), Err(NonZeroUsize::new(100 - v.len()).unwrap())); } #[test] @@ -180,11 +182,11 @@ fn test_iterator_rev_advance_back_by() { let mut iter = v.iter().rev(); assert_eq!(iter.advance_back_by(i), Ok(())); assert_eq!(iter.next_back().unwrap(), &v[i]); - assert_eq!(iter.advance_back_by(100), Err(v.len() - 1 - i)); + assert_eq!(iter.advance_back_by(100), Err(NonZeroUsize::new(100 - (v.len() - 1 - i)).unwrap())); } assert_eq!(v.iter().rev().advance_back_by(v.len()), Ok(())); - assert_eq!(v.iter().rev().advance_back_by(100), Err(v.len())); + assert_eq!(v.iter().rev().advance_back_by(100), Err(NonZeroUsize::new(100 - v.len()).unwrap())); } #[test] @@ -424,11 +426,11 @@ fn test_iterator_rev_advance_by() { let mut iter = v.iter().rev(); assert_eq!(iter.advance_by(i), Ok(())); assert_eq!(iter.next().unwrap(), &v[v.len() - 1 - i]); - assert_eq!(iter.advance_by(100), Err(v.len() - 1 - i)); + assert_eq!(iter.advance_by(100), Err(NonZeroUsize::new(100 - (v.len() - 1 - i)).unwrap())); } assert_eq!(v.iter().rev().advance_by(v.len()), Ok(())); - assert_eq!(v.iter().rev().advance_by(100), Err(v.len())); + assert_eq!(v.iter().rev().advance_by(100), Err(NonZeroUsize::new(100 - v.len()).unwrap())); } #[test] diff --git a/library/core/tests/slice.rs b/library/core/tests/slice.rs index 39559cdbb5e..88f54591bb4 100644 --- a/library/core/tests/slice.rs +++ b/library/core/tests/slice.rs @@ -1,6 +1,7 @@ use core::cell::Cell; use core::cmp::Ordering; use core::mem::MaybeUninit; +use core::num::NonZeroUsize; use core::result::Result::{Err, Ok}; use core::slice; @@ -142,20 +143,20 @@ fn test_iterator_advance_by() { for i in 0..=v.len() { let mut iter = v.iter(); - iter.advance_by(i).unwrap(); + assert_eq!(iter.advance_by(i), Ok(())); assert_eq!(iter.as_slice(), &v[i..]); } let mut iter = v.iter(); - assert_eq!(iter.advance_by(v.len() + 1), Err(v.len())); + assert_eq!(iter.advance_by(v.len() + 1), Err(NonZeroUsize::new(1).unwrap())); assert_eq!(iter.as_slice(), &[]); let mut iter = v.iter(); - iter.advance_by(3).unwrap(); + assert_eq!(iter.advance_by(3), Ok(())); assert_eq!(iter.as_slice(), &v[3..]); - iter.advance_by(2).unwrap(); + assert_eq!(iter.advance_by(2), Ok(())); assert_eq!(iter.as_slice(), &[]); - iter.advance_by(0).unwrap(); + assert_eq!(iter.advance_by(0), Ok(())); } #[test] @@ -164,20 +165,20 @@ fn test_iterator_advance_back_by() { for i in 0..=v.len() { let mut iter = v.iter(); - iter.advance_back_by(i).unwrap(); + assert_eq!(iter.advance_back_by(i), Ok(())); assert_eq!(iter.as_slice(), &v[..v.len() - i]); } let mut iter = v.iter(); - assert_eq!(iter.advance_back_by(v.len() + 1), Err(v.len())); + assert_eq!(iter.advance_back_by(v.len() + 1), Err(NonZeroUsize::new(1).unwrap())); assert_eq!(iter.as_slice(), &[]); let mut iter = v.iter(); - iter.advance_back_by(3).unwrap(); + assert_eq!(iter.advance_back_by(3), Ok(())); assert_eq!(iter.as_slice(), &v[..v.len() - 3]); - iter.advance_back_by(2).unwrap(); + assert_eq!(iter.advance_back_by(2), Ok(())); assert_eq!(iter.as_slice(), &[]); - iter.advance_back_by(0).unwrap(); + assert_eq!(iter.advance_back_by(0), Ok(())); } #[test] |