Skip to content

feat: add proper comparisons #786

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
alejandro-vaz wants to merge 6 commits into
base: v2
Choose a base branch
from
Open

feat: add proper comparisons #786

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
8c8bb4b
feat: add proper comparisons
alejandro-vaz Oct 21, 2026
603715a
style: formatting
alejandro-vaz Oct 21, 2026
1b8b0b8
Merge branch 'v2' into proper-comparisons
alejandro-vaz Oct 21, 2026
0c7fbf8
Merge branch 'v2' into proper-comparisons
alejandro-vaz Oct 21, 2026
df82a85
Merge branch 'v2' into proper-comparisons
alejandro-vaz Oct 21, 2026
b902a17
refactor: explicit cfgs
alejandro-vaz Oct 22, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion fuzz/fuzz_targets/main.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -161,8 +161,9 @@ fn test_with_inline_cap<const N: usize>(
small_vec = SmallVec::with_capacity(cap.0);
std_vec = Vec::with_capacity(cap.0);
}
#[allow(deprecated)]
Op::FromVec => {
small_vec = SmallVec::from(Into::<Vec<_>>::into(small_vec));
small_vec = SmallVec::from(small_vec.into_vec());
// No-op on `Vec`
}
Op::FromSlice(data) => {
Expand Down
319 changes: 274 additions & 45 deletions src/comparisons.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,3 +1,8 @@
#[cfg(feature = "equivalent")]
use equivalent::{
Comparable,
Equivalent
};
use {
super::{
SmallVec,
Expand All @@ -11,68 +16,292 @@ use {
core::cmp::Ordering
};

macro_rules! __impl_slice_eq1 {
([$($vars:tt)*] $lhs:ty, $rhs:ty $(where $ty:ty: $bound:ident)?) => {
impl<Item, U, Heap: Allocator, const INLINE: usize, $($vars)*> PartialEq<$rhs> for $lhs
where
Item: PartialEq<U>,
$($ty: $bound)?
{
macro_rules! implementation {
([$($generics:tt)*] for $left:ty =? $right:ty $(where $typename:ty: $bound:ident)?) => {
impl<
Item: PartialEq<Other>,
Other,
Heap: Allocator,
const INLINE: usize,
$($generics)*
> PartialEq<$right> for $left $(where $typename: $bound)? {
#[inline]
fn eq(&self, other: &$right) -> bool {
*AsRef::<[Item]>::as_ref(self) == *AsRef::<[Other]>::as_ref(other)
}
}
};
([$($generics:tt)*] for $left:ty =<> $right:ty $(where $typename:ty: $bound:ident)?) => {
impl<
Item: PartialOrd<Other>,
Other,
Heap: Allocator,
const INLINE: usize,
$($generics)*
> PartialOrd<$right> for $left $(where $typename: $bound)? {
#[inline]
fn partial_cmp(&self, other: &$right) -> Option<Ordering> {
AsRef::<[Item]>::as_ref(self).iter().partial_cmp(AsRef::<[Other]>::as_ref(other))
}
}
};
([$($generics:tt)*] for $left:ty =?+ $right:ty $(where $typename:ty: $bound:ident)?) => {
impl<
Item: Equivalent<Other>,
Other,
Heap: Allocator,
const INLINE: usize,
$($generics)*
> Equivalent<$right> for $left $(where $typename: $bound)? {
#[inline]
fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] }
fn equivalent(&self, key: &$right) -> bool {
self.len() == key.len() && self.iter()
.zip(AsRef::<[Other]>::as_ref(key))
.all(|(item, key)| item.equivalent(key))
}
}
};
([$($generics:tt)*] for $left:ty =<>+ $right:ty $(where $typename:ty: $bound:ident)?) => {
impl<
Item: Comparable<Other>,
Other,
Heap: Allocator,
const INLINE: usize,
$($generics)*
> Comparable<$right> for $left $(where $typename: $bound)? {
fn compare(&self, other: &$right) -> Ordering {
self.iter()
.zip(AsRef::<[Other]>::as_ref(other))
.map(|(item, key)| item.compare(key))
.find(|&ordering| ordering != Ordering::Equal)
.unwrap_or_else(|| self.len().cmp(&other.len()))
}
}
}
}

__impl_slice_eq1! { [const M: usize, A2: Allocator]
SmallVec<Item, M, Heap>,
SmallVec<U, INLINE, A2>
implementation!([const LENGTH: usize, Assigner: Allocator] for SmallVec<Item, INLINE, Heap> =? SmallVec<Other, LENGTH, Assigner>);
impl<Item: Eq, const INLINE: usize, Heap: Allocator> Eq for SmallVec<Item, INLINE, Heap> {}
implementation!([const LENGTH: usize, Assigner: Allocator] for SmallVec<Item, INLINE, Heap> =<> SmallVec<Other, LENGTH, Assigner>);
impl<Item: Ord, const INLINE: usize, Heap: Allocator> Ord for SmallVec<Item, INLINE, Heap> {
#[inline]
fn cmp(&self, other: &SmallVec<Item, INLINE, Heap>) -> Ordering {
self.as_ref().cmp(other.as_ref())
}
}
__impl_slice_eq1! { [const M: usize] SmallVec<Item, M, Heap>, [U; INLINE] }
__impl_slice_eq1! { [const M: usize] SmallVec<Item, M, Heap>, &[U; INLINE] }
__impl_slice_eq1! { [] SmallVec<Item, INLINE, Heap>, [U] }
__impl_slice_eq1! { [] SmallVec<Item, INLINE, Heap>, &[U] }
__impl_slice_eq1! { [] SmallVec<Item, INLINE, Heap>, &mut [U] }
__impl_slice_eq1! { [] [Item], SmallVec<U, INLINE, Heap> }
__impl_slice_eq1! { [] &[Item], SmallVec<U, INLINE, Heap> }
__impl_slice_eq1! { [] &mut [Item], SmallVec<U, INLINE, Heap> }
__impl_slice_eq1! { [] Vec<Item>, SmallVec<U, INLINE, Heap> }
__impl_slice_eq1! { [] SmallVec<Item, INLINE, Heap>, Vec<U> }
__impl_slice_eq1! { [] Cow<'_, [Item]>, SmallVec<U, INLINE, Heap> where Item: Clone }
__impl_slice_eq1! { [] SmallVec<Item, INLINE, Heap>, Cow<'_, [U]> where U: Clone }

impl<Item, U, const INLINE: usize, Heap: Allocator> PartialEq<SmallVec<U, INLINE, Heap>>
for VecDeque<Item>
where Item: PartialEq<U>
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =? [Other; LENGTH]);
implementation!([const LENGTH: usize] for [Item; INLINE] =? SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =?+ [Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for [Item; INLINE] =?+ SmallVec<Other, LENGTH, Heap>);
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<> [Other; LENGTH]);
implementation!([const LENGTH: usize] for [Item; INLINE] =<> SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<>+ [Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for [Item; INLINE] =<>+ SmallVec<Other, LENGTH, Heap>);

implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =? &[Other; LENGTH]);
implementation!([const LENGTH: usize] for &[Item; INLINE] =? SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =?+ &[Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for &[Item; INLINE] =?+ SmallVec<Other, LENGTH, Heap>);
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<> &[Other; LENGTH]);
implementation!([const LENGTH: usize] for &[Item; INLINE] =<> SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<>+ &[Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for &[Item; INLINE] =<>+ SmallVec<Other, LENGTH, Heap>);

implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =? &mut [Other; LENGTH]);
implementation!([const LENGTH: usize] for &mut [Item; INLINE] =? SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =?+ &mut [Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for &mut [Item; INLINE] =?+ SmallVec<Other, LENGTH, Heap>);
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<> &mut [Other; LENGTH]);
implementation!([const LENGTH: usize] for &mut [Item; INLINE] =<> SmallVec<Other, LENGTH, Heap>);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for SmallVec<Item, INLINE, Heap> =<>+ &mut [Other; LENGTH]);
#[cfg(feature = "equivalent")]
implementation!([const LENGTH: usize] for &mut [Item; INLINE] =<>+ SmallVec<Other, LENGTH, Heap>);

implementation!([] for SmallVec<Item, INLINE, Heap> =? [Other]);
implementation!([] for [Item] =? SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =?+ [Other]);
implementation!([] for SmallVec<Item, INLINE, Heap> =<> [Other]);
implementation!([] for [Item] =<> SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =<>+ [Other]);

implementation!([] for SmallVec<Item, INLINE, Heap> =? &[Other]);
implementation!([] for &[Item] =? SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =?+ &[Other]);
#[cfg(feature = "equivalent")]
implementation!([] for &[Item] =?+ SmallVec<Other, INLINE, Heap>);
implementation!([] for SmallVec<Item, INLINE, Heap> =<> &[Other]);
implementation!([] for &[Item] =<> SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =<>+ &[Other]);
#[cfg(feature = "equivalent")]
implementation!([] for &[Item] =<>+ SmallVec<Other, INLINE, Heap>);

implementation!([] for SmallVec<Item, INLINE, Heap> =? &mut [Other]);
implementation!([] for &mut [Item] =? SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =?+ &mut [Other]);
#[cfg(feature = "equivalent")]
implementation!([] for &mut [Item] =?+ SmallVec<Other, INLINE, Heap>);
implementation!([] for SmallVec<Item, INLINE, Heap> =<> &mut [Other]);
implementation!([] for &mut [Item] =<> SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =<>+ &mut [Other]);
#[cfg(feature = "equivalent")]
implementation!([] for &mut [Item] =<>+ SmallVec<Other, INLINE, Heap>);

implementation!([] for SmallVec<Item, INLINE, Heap> =? Vec<Other>);
implementation!([] for Vec<Item> =? SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =?+ Vec<Other>);
#[cfg(feature = "equivalent")]
implementation!([] for Vec<Item> =?+ SmallVec<Other, INLINE, Heap>);
implementation!([] for SmallVec<Item, INLINE, Heap> =<> Vec<Other>);
implementation!([] for Vec<Item> =<> SmallVec<Other, INLINE, Heap>);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =<>+ Vec<Other>);
#[cfg(feature = "equivalent")]
implementation!([] for Vec<Item> =<>+ SmallVec<Other, INLINE, Heap>);

implementation!([] for SmallVec<Item, INLINE, Heap> =? Cow<'_, [Other]> where Other: Clone);
implementation!([] for Cow<'_, [Item]> =? SmallVec<Other, INLINE, Heap> where Item: Clone);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =?+ Cow<'_, [Other]> where Other: Clone);
#[cfg(feature = "equivalent")]
implementation!([] for Cow<'_, [Item]> =?+ SmallVec<Other, INLINE, Heap> where Item: Clone);
implementation!([] for SmallVec<Item, INLINE, Heap> =<> Cow<'_, [Other]> where Other: Clone);
implementation!([] for Cow<'_, [Item]> =<> SmallVec<Other, INLINE, Heap> where Item: Clone);
#[cfg(feature = "equivalent")]
implementation!([] for SmallVec<Item, INLINE, Heap> =<>+ Cow<'_, [Other]> where Other: Clone);
#[cfg(feature = "equivalent")]
implementation!([] for Cow<'_, [Item]> =<>+ SmallVec<Other, INLINE, Heap> where Item: Clone);

impl<Item: PartialEq<Other>, Other, const INLINE: usize, Heap: Allocator>
PartialEq<SmallVec<Other, INLINE, Heap>> for VecDeque<Item>
{
#[inline]
fn eq(&self, other: &SmallVec<U, INLINE, Heap>) -> bool {
let other = other.as_ref();
if self.len() != other.len() {
fn eq(&self, other: &SmallVec<Other, INLINE, Heap>) -> bool {
let (first, second) = self.as_slices();
let Some((before, after)) = other.split_at_checked(first.len()) else {
return false;
}
let (sa, sb) = self.as_slices();
let (oa, ob) = other[..].split_at(sa.len());
sa == oa && sb == ob
};
first == before && second == after
}
}

impl<Item: Eq, const INLINE: usize, Heap: Allocator> Eq for SmallVec<Item, INLINE, Heap> {}

impl<Item, const INLINE: usize, Heap: Allocator> PartialOrd for SmallVec<Item, INLINE, Heap>
where Item: PartialOrd
impl<Item: PartialEq<Other>, Other, const INLINE: usize, Heap: Allocator> PartialEq<VecDeque<Other>>
for SmallVec<Item, INLINE, Heap>
{
#[inline]
fn partial_cmp(&self, other: &SmallVec<Item, INLINE, Heap>) -> Option<Ordering> {
self.as_ref().partial_cmp(other.as_ref())
fn eq(&self, other: &VecDeque<Other>) -> bool {
let (first, second) = other.as_slices();
let Some((before, after)) = self.split_at_checked(first.len()) else {
return false;
};
before == first && after == second
}
}

impl<Item, const INLINE: usize, Heap: Allocator> Ord for SmallVec<Item, INLINE, Heap>
where Item: Ord
#[cfg(feature = "equivalent")]
impl<Item: Equivalent<Other>, Other, const INLINE: usize, Heap: Allocator>
Equivalent<SmallVec<Other, INLINE, Heap>> for VecDeque<Item>
{
#[inline]
fn cmp(&self, other: &SmallVec<Item, INLINE, Heap>) -> Ordering {
self.as_ref().cmp(other.as_ref())
fn equivalent(&self, key: &SmallVec<Other, INLINE, Heap>) -> bool {
let (first, second) = self.as_slices();
let Some((before, after)) = key.split_at_checked(first.len()) else {
return false;
};
first.len() == before.len()
&& first
.iter()
.zip(before)
.all(|(item, key)| item.equivalent(key))
&& second.len() == after.len()
&& second
.iter()
.zip(after)
.all(|(item, key)| item.equivalent(key))
}
}
#[cfg(feature = "equivalent")]
impl<Item: Equivalent<Other>, Other, const INLINE: usize, Heap: Allocator>
Equivalent<VecDeque<Other>> for SmallVec<Item, INLINE, Heap>
{
#[inline]
fn equivalent(&self, key: &VecDeque<Other>) -> bool {
let (first, second) = key.as_slices();
let Some((before, after)) = self.split_at_checked(first.len()) else {
return false;
};
first.len() == before.len()
&& first
.iter()
.zip(before)
.all(|(item, key)| key.equivalent(item))
&& second.len() == after.len()
&& second
.iter()
.zip(after)
.all(|(item, key)| key.equivalent(item))
}
}
impl<Item: PartialOrd<Other>, Other, const INLINE: usize, Heap: Allocator>
PartialOrd<SmallVec<Other, INLINE, Heap>> for VecDeque<Item>
{
#[inline]
fn partial_cmp(&self, other: &SmallVec<Other, INLINE, Heap>) -> Option<Ordering> {
self.iter().partial_cmp(other.iter())
}
}
impl<Item: PartialOrd<Other>, Other, const INLINE: usize, Heap: Allocator>
PartialOrd<VecDeque<Other>> for SmallVec<Item, INLINE, Heap>
{
#[inline]
fn partial_cmp(&self, other: &VecDeque<Other>) -> Option<Ordering> {
self.iter().partial_cmp(other.iter())
}
}
#[cfg(feature = "equivalent")]
impl<Item: Comparable<Other>, Other, const INLINE: usize, Heap: Allocator>
Comparable<SmallVec<Other, INLINE, Heap>> for VecDeque<Item>
{
#[inline]
fn compare(&self, key: &SmallVec<Other, INLINE, Heap>) -> Ordering {
let (first, second) = self.as_slices();
first
.iter()
.chain(second.iter())
.map(|item| item)
.zip(key.iter())
.map(|(item, key)| item.compare(key))
.find(|&ordering| ordering != Ordering::Equal)
.unwrap_or_else(|| self.len().cmp(&key.len()))
}
}
#[cfg(feature = "equivalent")]
impl<Item: Comparable<Other>, Other, const INLINE: usize, Heap: Allocator>
Comparable<VecDeque<Other>> for SmallVec<Item, INLINE, Heap>
{
#[inline]
fn compare(&self, key: &VecDeque<Other>) -> Ordering {
let (first, second) = key.as_slices();
self.iter()
.zip(first.iter().chain(second.iter()))
.map(|(item, key)| item.compare(key))
.find(|&ordering| ordering != Ordering::Equal)
.unwrap_or_else(|| self.len().cmp(&key.len()))
}
}
11 changes: 0 additions & 11 deletions src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1833,17 +1833,6 @@ impl<Item: Debug, const INLINE: usize, Heap: Allocator> Debug for SmallVec<Item,
}
}

#[cfg(feature = "equivalent")]
#[cfg_attr(docsrs, doc(cfg(feature = "equivalent")))]
impl<Item, Other, const INLINE: usize, Heap: Allocator> equivalent::Equivalent<[Other]>
for SmallVec<Item, INLINE, Heap>
where Item: equivalent::Equivalent<Other>
{
fn equivalent(&self, key: &[Other]) -> bool {
self.len() == key.len() && self.iter().zip(key).all(|(item, key)| item.equivalent(key))
}
}

#[cfg(feature = "zeroize")]
impl<Item: Zeroize, const INLINE: usize, Heap: Allocator> Zeroize for SmallVec<Item, INLINE, Heap> {
fn zeroize(&mut self) {
Expand Down
Loading