diff options
Diffstat (limited to 'vendor/la-arena')
-rw-r--r-- | vendor/la-arena/.cargo-checksum.json | 1 | ||||
-rw-r--r-- | vendor/la-arena/Cargo.toml | 25 | ||||
-rw-r--r-- | vendor/la-arena/src/lib.rs | 526 | ||||
-rw-r--r-- | vendor/la-arena/src/map.rs | 304 |
4 files changed, 856 insertions, 0 deletions
diff --git a/vendor/la-arena/.cargo-checksum.json b/vendor/la-arena/.cargo-checksum.json new file mode 100644 index 000000000..15724b475 --- /dev/null +++ b/vendor/la-arena/.cargo-checksum.json @@ -0,0 +1 @@ +{"files":{"Cargo.toml":"e0ab2202ba612192387ce7931e940310ea6e80890fab03085f9398242ea91f6e","src/lib.rs":"3bb0569f60631442a07c9ebc31dc93d15ee34ee4ffdcdd6f8e5d527acae87d3f","src/map.rs":"c771c4921050eb5256759214995cbe3343217178efe9df14885cc715eaa0fc99"},"package":"3752f229dcc5a481d60f385fa479ff46818033d881d2d801aa27dffcfb5e8306"}
\ No newline at end of file diff --git a/vendor/la-arena/Cargo.toml b/vendor/la-arena/Cargo.toml new file mode 100644 index 000000000..f38dc4311 --- /dev/null +++ b/vendor/la-arena/Cargo.toml @@ -0,0 +1,25 @@ +# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO +# +# When uploading crates to the registry Cargo will automatically +# "normalize" Cargo.toml files for maximal compatibility +# with all versions of Cargo and also rewrite `path` dependencies +# to registry (e.g., crates.io) dependencies. +# +# If you are reading this file be aware that the original Cargo.toml +# will likely look very different (and much more reasonable). +# See Cargo.toml.orig for the original contents. + +[package] +edition = "2021" +rust-version = "1.56" +name = "la-arena" +version = "0.3.1" +description = "Simple index-based arena without deletion." +documentation = "https://docs.rs/la-arena" +categories = [ + "data-structures", + "memory-management", + "rust-patterns", +] +license = "MIT OR Apache-2.0" +repository = "https://github.com/rust-lang/rust-analyzer/tree/master/lib/la-arena" diff --git a/vendor/la-arena/src/lib.rs b/vendor/la-arena/src/lib.rs new file mode 100644 index 000000000..f39c3a3e4 --- /dev/null +++ b/vendor/la-arena/src/lib.rs @@ -0,0 +1,526 @@ +//! Yet another index-based arena. + +#![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)] +#![warn(missing_docs)] + +use std::{ + cmp, fmt, + hash::{Hash, Hasher}, + iter::{Enumerate, FusedIterator}, + marker::PhantomData, + ops::{Index, IndexMut, Range, RangeInclusive}, +}; + +mod map; +pub use map::{ArenaMap, Entry, OccupiedEntry, VacantEntry}; + +/// The raw index of a value in an arena. +#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub struct RawIdx(u32); + +impl RawIdx { + /// Constructs a [`RawIdx`] from a u32. + pub const fn from_u32(u32: u32) -> Self { + RawIdx(u32) + } + + /// Deconstructs a [`RawIdx`] into the underlying u32. + pub const fn into_u32(self) -> u32 { + self.0 + } +} + +impl From<RawIdx> for u32 { + #[inline] + fn from(raw: RawIdx) -> u32 { + raw.0 + } +} + +impl From<u32> for RawIdx { + #[inline] + fn from(idx: u32) -> RawIdx { + RawIdx(idx) + } +} + +impl fmt::Debug for RawIdx { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +impl fmt::Display for RawIdx { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +/// The index of a value allocated in an arena that holds `T`s. +pub struct Idx<T> { + raw: RawIdx, + _ty: PhantomData<fn() -> T>, +} + +impl<T> Ord for Idx<T> { + fn cmp(&self, other: &Self) -> cmp::Ordering { + self.raw.cmp(&other.raw) + } +} + +impl<T> PartialOrd for Idx<T> { + fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> { + self.raw.partial_cmp(&other.raw) + } +} + +impl<T> Clone for Idx<T> { + fn clone(&self) -> Self { + *self + } +} +impl<T> Copy for Idx<T> {} + +impl<T> PartialEq for Idx<T> { + fn eq(&self, other: &Idx<T>) -> bool { + self.raw == other.raw + } +} +impl<T> Eq for Idx<T> {} + +impl<T> Hash for Idx<T> { + fn hash<H: Hasher>(&self, state: &mut H) { + self.raw.hash(state); + } +} + +impl<T> fmt::Debug for Idx<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut type_name = std::any::type_name::<T>(); + if let Some(idx) = type_name.rfind(':') { + type_name = &type_name[idx + 1..]; + } + write!(f, "Idx::<{}>({})", type_name, self.raw) + } +} + +impl<T> Idx<T> { + /// Creates a new index from a [`RawIdx`]. + pub const fn from_raw(raw: RawIdx) -> Self { + Idx { raw, _ty: PhantomData } + } + + /// Converts this index into the underlying [`RawIdx`]. + pub const fn into_raw(self) -> RawIdx { + self.raw + } +} + +/// A range of densely allocated arena values. +pub struct IdxRange<T> { + range: Range<u32>, + _p: PhantomData<T>, +} + +impl<T> IdxRange<T> { + /// Creates a new index range + /// inclusive of the start value and exclusive of the end value. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let a = arena.alloc("a"); + /// let b = arena.alloc("b"); + /// let c = arena.alloc("c"); + /// let d = arena.alloc("d"); + /// + /// let range = la_arena::IdxRange::new(b..d); + /// assert_eq!(&arena[range], &["b", "c"]); + /// ``` + pub fn new(range: Range<Idx<T>>) -> Self { + Self { range: range.start.into_raw().into()..range.end.into_raw().into(), _p: PhantomData } + } + + /// Creates a new index range + /// inclusive of the start value and end value. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let foo = arena.alloc("foo"); + /// let bar = arena.alloc("bar"); + /// let baz = arena.alloc("baz"); + /// + /// let range = la_arena::IdxRange::new_inclusive(foo..=baz); + /// assert_eq!(&arena[range], &["foo", "bar", "baz"]); + /// + /// let range = la_arena::IdxRange::new_inclusive(foo..=foo); + /// assert_eq!(&arena[range], &["foo"]); + /// ``` + pub fn new_inclusive(range: RangeInclusive<Idx<T>>) -> Self { + Self { + range: u32::from(range.start().into_raw())..u32::from(range.end().into_raw()) + 1, + _p: PhantomData, + } + } + + /// Returns whether the index range is empty. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let one = arena.alloc(1); + /// let two = arena.alloc(2); + /// + /// assert!(la_arena::IdxRange::new(one..one).is_empty()); + /// ``` + pub fn is_empty(&self) -> bool { + self.range.is_empty() + } + + /// Returns the start of the index range. + pub fn start(&self) -> Idx<T> { + Idx::from_raw(RawIdx::from(self.range.start)) + } + + /// Returns the end of the index range. + pub fn end(&self) -> Idx<T> { + Idx::from_raw(RawIdx::from(self.range.end)) + } +} + +impl<T> Iterator for IdxRange<T> { + type Item = Idx<T>; + + fn next(&mut self) -> Option<Self::Item> { + self.range.next().map(|raw| Idx::from_raw(raw.into())) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.range.size_hint() + } + + fn count(self) -> usize + where + Self: Sized, + { + self.range.count() + } + + fn last(self) -> Option<Self::Item> + where + Self: Sized, + { + self.range.last().map(|raw| Idx::from_raw(raw.into())) + } + + fn nth(&mut self, n: usize) -> Option<Self::Item> { + self.range.nth(n).map(|raw| Idx::from_raw(raw.into())) + } +} + +impl<T> DoubleEndedIterator for IdxRange<T> { + fn next_back(&mut self) -> Option<Self::Item> { + self.range.next_back().map(|raw| Idx::from_raw(raw.into())) + } +} + +impl<T> ExactSizeIterator for IdxRange<T> {} + +impl<T> FusedIterator for IdxRange<T> {} + +impl<T> fmt::Debug for IdxRange<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_tuple(&format!("IdxRange::<{}>", std::any::type_name::<T>())) + .field(&self.range) + .finish() + } +} + +impl<T> Clone for IdxRange<T> { + fn clone(&self) -> Self { + Self { range: self.range.clone(), _p: PhantomData } + } +} + +impl<T> PartialEq for IdxRange<T> { + fn eq(&self, other: &Self) -> bool { + self.range == other.range + } +} + +impl<T> Eq for IdxRange<T> {} + +/// Yet another index-based arena. +#[derive(Clone, PartialEq, Eq, Hash)] +pub struct Arena<T> { + data: Vec<T>, +} + +impl<T: fmt::Debug> fmt::Debug for Arena<T> { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt.debug_struct("Arena").field("len", &self.len()).field("data", &self.data).finish() + } +} + +impl<T> Arena<T> { + /// Creates a new empty arena. + /// + /// ``` + /// let arena: la_arena::Arena<i32> = la_arena::Arena::new(); + /// assert!(arena.is_empty()); + /// ``` + pub const fn new() -> Arena<T> { + Arena { data: Vec::new() } + } + + /// Create a new empty arena with specific capacity. + /// + /// ``` + /// let arena: la_arena::Arena<i32> = la_arena::Arena::with_capacity(42); + /// assert!(arena.is_empty()); + /// ``` + pub fn with_capacity(capacity: usize) -> Arena<T> { + Arena { data: Vec::with_capacity(capacity) } + } + + /// Empties the arena, removing all contained values. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// + /// arena.alloc(1); + /// arena.alloc(2); + /// arena.alloc(3); + /// assert_eq!(arena.len(), 3); + /// + /// arena.clear(); + /// assert!(arena.is_empty()); + /// ``` + pub fn clear(&mut self) { + self.data.clear(); + } + + /// Returns the length of the arena. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// assert_eq!(arena.len(), 0); + /// + /// arena.alloc("foo"); + /// assert_eq!(arena.len(), 1); + /// + /// arena.alloc("bar"); + /// assert_eq!(arena.len(), 2); + /// + /// arena.alloc("baz"); + /// assert_eq!(arena.len(), 3); + /// ``` + pub fn len(&self) -> usize { + self.data.len() + } + + /// Returns whether the arena contains no elements. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// assert!(arena.is_empty()); + /// + /// arena.alloc(0.5); + /// assert!(!arena.is_empty()); + /// ``` + pub fn is_empty(&self) -> bool { + self.data.is_empty() + } + + /// Allocates a new value on the arena, returning the value’s index. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let idx = arena.alloc(50); + /// + /// assert_eq!(arena[idx], 50); + /// ``` + pub fn alloc(&mut self, value: T) -> Idx<T> { + let idx = self.next_idx(); + self.data.push(value); + idx + } + + /// Densely allocates multiple values, returning the values’ index range. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let range = arena.alloc_many(0..4); + /// + /// assert_eq!(arena[range], [0, 1, 2, 3]); + /// ``` + pub fn alloc_many<II: IntoIterator<Item = T>>(&mut self, iter: II) -> IdxRange<T> { + let start = self.next_idx(); + self.extend(iter); + let end = self.next_idx(); + IdxRange::new(start..end) + } + + /// Returns an iterator over the arena’s elements. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let idx1 = arena.alloc(20); + /// let idx2 = arena.alloc(40); + /// let idx3 = arena.alloc(60); + /// + /// let mut iterator = arena.iter(); + /// assert_eq!(iterator.next(), Some((idx1, &20))); + /// assert_eq!(iterator.next(), Some((idx2, &40))); + /// assert_eq!(iterator.next(), Some((idx3, &60))); + /// ``` + pub fn iter( + &self, + ) -> impl Iterator<Item = (Idx<T>, &T)> + ExactSizeIterator + DoubleEndedIterator + Clone { + self.data.iter().enumerate().map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value)) + } + + /// Returns an iterator over the arena’s mutable elements. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let idx1 = arena.alloc(20); + /// + /// assert_eq!(arena[idx1], 20); + /// + /// let mut iterator = arena.iter_mut(); + /// *iterator.next().unwrap().1 = 10; + /// drop(iterator); + /// + /// assert_eq!(arena[idx1], 10); + /// ``` + pub fn iter_mut( + &mut self, + ) -> impl Iterator<Item = (Idx<T>, &mut T)> + ExactSizeIterator + DoubleEndedIterator { + self.data + .iter_mut() + .enumerate() + .map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value)) + } + + /// Returns an iterator over the arena’s values. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let idx1 = arena.alloc(20); + /// let idx2 = arena.alloc(40); + /// let idx3 = arena.alloc(60); + /// + /// let mut iterator = arena.values(); + /// assert_eq!(iterator.next(), Some(&20)); + /// assert_eq!(iterator.next(), Some(&40)); + /// assert_eq!(iterator.next(), Some(&60)); + /// ``` + pub fn values(&self) -> impl Iterator<Item = &T> + ExactSizeIterator + DoubleEndedIterator { + self.data.iter() + } + + /// Returns an iterator over the arena’s mutable values. + /// + /// ``` + /// let mut arena = la_arena::Arena::new(); + /// let idx1 = arena.alloc(20); + /// + /// assert_eq!(arena[idx1], 20); + /// + /// let mut iterator = arena.values_mut(); + /// *iterator.next().unwrap() = 10; + /// drop(iterator); + /// + /// assert_eq!(arena[idx1], 10); + /// ``` + pub fn values_mut( + &mut self, + ) -> impl Iterator<Item = &mut T> + ExactSizeIterator + DoubleEndedIterator { + self.data.iter_mut() + } + + /// Reallocates the arena to make it take up as little space as possible. + pub fn shrink_to_fit(&mut self) { + self.data.shrink_to_fit(); + } + + /// Returns the index of the next value allocated on the arena. + /// + /// This method should remain private to make creating invalid `Idx`s harder. + fn next_idx(&self) -> Idx<T> { + Idx::from_raw(RawIdx(self.data.len() as u32)) + } +} + +impl<T> AsMut<[T]> for Arena<T> { + fn as_mut(&mut self) -> &mut [T] { + self.data.as_mut() + } +} + +impl<T> Default for Arena<T> { + fn default() -> Arena<T> { + Arena { data: Vec::new() } + } +} + +impl<T> Index<Idx<T>> for Arena<T> { + type Output = T; + fn index(&self, idx: Idx<T>) -> &T { + let idx = idx.into_raw().0 as usize; + &self.data[idx] + } +} + +impl<T> IndexMut<Idx<T>> for Arena<T> { + fn index_mut(&mut self, idx: Idx<T>) -> &mut T { + let idx = idx.into_raw().0 as usize; + &mut self.data[idx] + } +} + +impl<T> Index<IdxRange<T>> for Arena<T> { + type Output = [T]; + fn index(&self, range: IdxRange<T>) -> &[T] { + let start = range.range.start as usize; + let end = range.range.end as usize; + &self.data[start..end] + } +} + +impl<T> FromIterator<T> for Arena<T> { + fn from_iter<I>(iter: I) -> Self + where + I: IntoIterator<Item = T>, + { + Arena { data: Vec::from_iter(iter) } + } +} + +/// An iterator over the arena’s elements. +pub struct IntoIter<T>(Enumerate<<Vec<T> as IntoIterator>::IntoIter>); + +impl<T> Iterator for IntoIter<T> { + type Item = (Idx<T>, T); + + fn next(&mut self) -> Option<Self::Item> { + self.0.next().map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value)) + } +} + +impl<T> IntoIterator for Arena<T> { + type Item = (Idx<T>, T); + + type IntoIter = IntoIter<T>; + + fn into_iter(self) -> Self::IntoIter { + IntoIter(self.data.into_iter().enumerate()) + } +} + +impl<T> Extend<T> for Arena<T> { + fn extend<II: IntoIterator<Item = T>>(&mut self, iter: II) { + for t in iter { + self.alloc(t); + } + } +} diff --git a/vendor/la-arena/src/map.rs b/vendor/la-arena/src/map.rs new file mode 100644 index 000000000..750f345b5 --- /dev/null +++ b/vendor/la-arena/src/map.rs @@ -0,0 +1,304 @@ +use std::iter::Enumerate; +use std::marker::PhantomData; + +use crate::Idx; + +/// A map from arena indexes to some other type. +/// Space requirement is O(highest index). +#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub struct ArenaMap<IDX, V> { + v: Vec<Option<V>>, + _ty: PhantomData<IDX>, +} + +impl<T, V> ArenaMap<Idx<T>, V> { + /// Creates a new empty map. + pub const fn new() -> Self { + Self { v: Vec::new(), _ty: PhantomData } + } + + /// Create a new empty map with specific capacity. + pub fn with_capacity(capacity: usize) -> Self { + Self { v: Vec::with_capacity(capacity), _ty: PhantomData } + } + + /// Reserves capacity for at least additional more elements to be inserted in the map. + pub fn reserve(&mut self, additional: usize) { + self.v.reserve(additional); + } + + /// Clears the map, removing all elements. + pub fn clear(&mut self) { + self.v.clear(); + } + + /// Shrinks the capacity of the map as much as possible. + pub fn shrink_to_fit(&mut self) { + let min_len = self.v.iter().rposition(|slot| slot.is_some()).map_or(0, |i| i + 1); + self.v.truncate(min_len); + self.v.shrink_to_fit(); + } + + /// Returns whether the map contains a value for the specified index. + pub fn contains_idx(&self, idx: Idx<T>) -> bool { + matches!(self.v.get(Self::to_idx(idx)), Some(Some(_))) + } + + /// Removes an index from the map, returning the value at the index if the index was previously in the map. + pub fn remove(&mut self, idx: Idx<T>) -> Option<V> { + self.v.get_mut(Self::to_idx(idx))?.take() + } + + /// Inserts a value associated with a given arena index into the map. + /// + /// If the map did not have this index present, None is returned. + /// Otherwise, the value is updated, and the old value is returned. + pub fn insert(&mut self, idx: Idx<T>, t: V) -> Option<V> { + let idx = Self::to_idx(idx); + + self.v.resize_with((idx + 1).max(self.v.len()), || None); + self.v[idx].replace(t) + } + + /// Returns a reference to the value associated with the provided index + /// if it is present. + pub fn get(&self, idx: Idx<T>) -> Option<&V> { + self.v.get(Self::to_idx(idx)).and_then(|it| it.as_ref()) + } + + /// Returns a mutable reference to the value associated with the provided index + /// if it is present. + pub fn get_mut(&mut self, idx: Idx<T>) -> Option<&mut V> { + self.v.get_mut(Self::to_idx(idx)).and_then(|it| it.as_mut()) + } + + /// Returns an iterator over the values in the map. + pub fn values(&self) -> impl Iterator<Item = &V> + DoubleEndedIterator { + self.v.iter().filter_map(|o| o.as_ref()) + } + + /// Returns an iterator over mutable references to the values in the map. + pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> + DoubleEndedIterator { + self.v.iter_mut().filter_map(|o| o.as_mut()) + } + + /// Returns an iterator over the arena indexes and values in the map. + pub fn iter(&self) -> impl Iterator<Item = (Idx<T>, &V)> + DoubleEndedIterator { + self.v.iter().enumerate().filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_ref()?))) + } + + /// Returns an iterator over the arena indexes and values in the map. + pub fn iter_mut(&mut self) -> impl Iterator<Item = (Idx<T>, &mut V)> { + self.v + .iter_mut() + .enumerate() + .filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_mut()?))) + } + + /// Gets the given key's corresponding entry in the map for in-place manipulation. + pub fn entry(&mut self, idx: Idx<T>) -> Entry<'_, Idx<T>, V> { + let idx = Self::to_idx(idx); + self.v.resize_with((idx + 1).max(self.v.len()), || None); + match &mut self.v[idx] { + slot @ Some(_) => Entry::Occupied(OccupiedEntry { slot, _ty: PhantomData }), + slot @ None => Entry::Vacant(VacantEntry { slot, _ty: PhantomData }), + } + } + + fn to_idx(idx: Idx<T>) -> usize { + u32::from(idx.into_raw()) as usize + } + + fn from_idx(idx: usize) -> Idx<T> { + Idx::from_raw((idx as u32).into()) + } +} + +impl<T, V> std::ops::Index<Idx<V>> for ArenaMap<Idx<V>, T> { + type Output = T; + fn index(&self, idx: Idx<V>) -> &T { + self.v[Self::to_idx(idx)].as_ref().unwrap() + } +} + +impl<T, V> std::ops::IndexMut<Idx<V>> for ArenaMap<Idx<V>, T> { + fn index_mut(&mut self, idx: Idx<V>) -> &mut T { + self.v[Self::to_idx(idx)].as_mut().unwrap() + } +} + +impl<T, V> Default for ArenaMap<Idx<V>, T> { + fn default() -> Self { + Self::new() + } +} + +impl<T, V> Extend<(Idx<V>, T)> for ArenaMap<Idx<V>, T> { + fn extend<I: IntoIterator<Item = (Idx<V>, T)>>(&mut self, iter: I) { + iter.into_iter().for_each(move |(k, v)| { + self.insert(k, v); + }); + } +} + +impl<T, V> FromIterator<(Idx<V>, T)> for ArenaMap<Idx<V>, T> { + fn from_iter<I: IntoIterator<Item = (Idx<V>, T)>>(iter: I) -> Self { + let mut this = Self::new(); + this.extend(iter); + this + } +} + +pub struct ArenaMapIter<IDX, V> { + iter: Enumerate<std::vec::IntoIter<Option<V>>>, + _ty: PhantomData<IDX>, +} + +impl<T, V> IntoIterator for ArenaMap<Idx<T>, V> { + type Item = (Idx<T>, V); + + type IntoIter = ArenaMapIter<Idx<T>, V>; + + fn into_iter(self) -> Self::IntoIter { + let iter = self.v.into_iter().enumerate(); + Self::IntoIter { iter, _ty: PhantomData } + } +} + +impl<T, V> ArenaMapIter<Idx<T>, V> { + fn mapper((idx, o): (usize, Option<V>)) -> Option<(Idx<T>, V)> { + Some((ArenaMap::<Idx<T>, V>::from_idx(idx), o?)) + } +} + +impl<T, V> Iterator for ArenaMapIter<Idx<T>, V> { + type Item = (Idx<T>, V); + + #[inline] + fn next(&mut self) -> Option<Self::Item> { + for next in self.iter.by_ref() { + match Self::mapper(next) { + Some(r) => return Some(r), + None => continue, + } + } + + None + } + + #[inline] + fn size_hint(&self) -> (usize, Option<usize>) { + self.iter.size_hint() + } +} + +impl<T, V> DoubleEndedIterator for ArenaMapIter<Idx<T>, V> { + #[inline] + fn next_back(&mut self) -> Option<Self::Item> { + while let Some(next_back) = self.iter.next_back() { + match Self::mapper(next_back) { + Some(r) => return Some(r), + None => continue, + } + } + + None + } +} + +/// A view into a single entry in a map, which may either be vacant or occupied. +/// +/// This `enum` is constructed from the [`entry`] method on [`ArenaMap`]. +/// +/// [`entry`]: ArenaMap::entry +pub enum Entry<'a, IDX, V> { + /// A vacant entry. + Vacant(VacantEntry<'a, IDX, V>), + /// An occupied entry. + Occupied(OccupiedEntry<'a, IDX, V>), +} + +impl<'a, IDX, V> Entry<'a, IDX, V> { + /// Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to + /// the value in the entry. + pub fn or_insert(self, default: V) -> &'a mut V { + match self { + Self::Vacant(ent) => ent.insert(default), + Self::Occupied(ent) => ent.into_mut(), + } + } + + /// Ensures a value is in the entry by inserting the result of the default function if empty, and returns + /// a mutable reference to the value in the entry. + pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { + match self { + Self::Vacant(ent) => ent.insert(default()), + Self::Occupied(ent) => ent.into_mut(), + } + } + + /// Provides in-place mutable access to an occupied entry before any potential inserts into the map. + pub fn and_modify<F: FnOnce(&mut V)>(mut self, f: F) -> Self { + if let Self::Occupied(ent) = &mut self { + f(ent.get_mut()); + } + self + } +} + +impl<'a, IDX, V> Entry<'a, IDX, V> +where + V: Default, +{ + /// Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference + /// to the value in the entry. + pub fn or_default(self) -> &'a mut V { + self.or_insert_with(Default::default) + } +} + +/// A view into an vacant entry in a [`ArenaMap`]. It is part of the [`Entry`] enum. +pub struct VacantEntry<'a, IDX, V> { + slot: &'a mut Option<V>, + _ty: PhantomData<IDX>, +} + +impl<'a, IDX, V> VacantEntry<'a, IDX, V> { + /// Sets the value of the entry with the `VacantEntry`’s key, and returns a mutable reference to it. + pub fn insert(self, value: V) -> &'a mut V { + self.slot.insert(value) + } +} + +/// A view into an occupied entry in a [`ArenaMap`]. It is part of the [`Entry`] enum. +pub struct OccupiedEntry<'a, IDX, V> { + slot: &'a mut Option<V>, + _ty: PhantomData<IDX>, +} + +impl<'a, IDX, V> OccupiedEntry<'a, IDX, V> { + /// Gets a reference to the value in the entry. + pub fn get(&self) -> &V { + self.slot.as_ref().expect("Occupied") + } + + /// Gets a mutable reference to the value in the entry. + pub fn get_mut(&mut self) -> &mut V { + self.slot.as_mut().expect("Occupied") + } + + /// Converts the entry into a mutable reference to its value. + pub fn into_mut(self) -> &'a mut V { + self.slot.as_mut().expect("Occupied") + } + + /// Sets the value of the entry with the `OccupiedEntry`’s key, and returns the entry’s old value. + pub fn insert(&mut self, value: V) -> V { + self.slot.replace(value).expect("Occupied") + } + + /// Takes the value of the entry out of the map, and returns it. + pub fn remove(self) -> V { + self.slot.take().expect("Occupied") + } +} |