vendor/litemap/src/map.rs - toolchain/rustc - Git at Google

 // This file is part of ICU4X. For terms of use, please see the file
 // called LICENSE at the top level of the ICU4X source tree
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

 use crate::store::*;
 use alloc::borrow::Borrow;
 use alloc::vec::Vec;
 use core::cmp::Ordering;
 use core::iter::FromIterator;
 use core::marker::PhantomData;
 use core::mem;
 use core::ops::{Index, IndexMut};

 /// A simple "flat" map based on a sorted vector
 ///
 /// See the [module level documentation][super] for why one should use this.
 ///
 /// The API is roughly similar to that of [`std::collections::BTreeMap`].
 #[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 #[cfg_attr(feature = "yoke", derive(yoke::Yokeable))]
 pub struct LiteMap<K: ?Sized, V: ?Sized, S = alloc::vec::Vec<(K, V)>> {
     pub(crate) values: S,
     pub(crate) _key_type: PhantomData<K>,
     pub(crate) _value_type: PhantomData<V>,
 }

 impl<K, V> LiteMap<K, V> {
     /// Construct a new [`LiteMap`] backed by Vec
     pub const fn new_vec() -> Self {
         Self {
             values: alloc::vec::Vec::new(),
             _key_type: PhantomData,
             _value_type: PhantomData,
         }
     }
 }

 impl<K, V, S> LiteMap<K, V, S> {
     /// Construct a new [`LiteMap`] using the given values
     ///
     /// The store must be sorted and have no duplicate keys.
     pub const fn from_sorted_store_unchecked(values: S) -> Self {
         Self {
             values,
             _key_type: PhantomData,
             _value_type: PhantomData,
         }
     }
 }

 impl<K, V> LiteMap<K, V, Vec<(K, V)>> {
     /// Convert a [`LiteMap`] into a sorted `Vec<(K, V)>`.
     #[inline]
     pub fn into_tuple_vec(self) -> Vec<(K, V)> {
         self.values
     }
 }

 impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
 where
     S: StoreConstEmpty<K, V>,
 {
     /// Create a new empty [`LiteMap`]
     pub const fn new() -> Self {
         Self {
             values: S::EMPTY,
             _key_type: PhantomData,
             _value_type: PhantomData,
         }
     }
 }

 impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
 where
     S: Store<K, V>,
 {
     /// The number of elements in the [`LiteMap`]
     pub fn len(&self) -> usize {
         self.values.lm_len()
     }

     /// Whether the [`LiteMap`] is empty
     pub fn is_empty(&self) -> bool {
         self.values.lm_is_empty()
     }

     /// Get the key-value pair residing at a particular index
     ///
     /// In most cases, prefer [`LiteMap::get()`] over this method.
     #[inline]
     pub fn get_indexed(&self, index: usize) -> Option<(&K, &V)> {
         self.values.lm_get(index)
     }
 }

 impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
 where
     K: Ord,
     S: Store<K, V>,
 {
     /// Get the value associated with `key`, if it exists.
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// assert_eq!(map.get(&1), Some(&"one"));
     /// assert_eq!(map.get(&3), None);
     /// ```
     pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V>
     where
         K: Borrow<Q>,
         Q: Ord,
     {
         match self.find_index(key) {
             #[allow(clippy::unwrap_used)] // find_index returns a valid index
             Ok(found) => Some(self.values.lm_get(found).unwrap().1),
             Err(_) => None,
         }
     }

     /// Binary search the map with `predicate` to find a key, returning the value.
     pub fn get_by(&self, predicate: impl FnMut(&K) -> Ordering) -> Option<&V> {
         let index = self.values.lm_binary_search_by(predicate).ok()?;
         self.values.lm_get(index).map(|(_, v)| v)
     }

     /// Returns whether `key` is contained in this map
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// assert!(map.contains_key(&1));
     /// assert!(!map.contains_key(&3));
     /// ```
     pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool
     where
         K: Borrow<Q>,
         Q: Ord,
     {
         self.find_index(key).is_ok()
     }

     /// Get the lowest-rank key/value pair from the `LiteMap`, if it exists.
     ///
     /// # Examples
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map: LiteMap<i32, &str, Vec<_>> =
     ///     LiteMap::from_iter([(1, "uno"), (3, "tres")].into_iter());
     ///
     /// assert_eq!(map.first(), Some((&1, &"uno")));
     /// ```
     #[inline]
     pub fn first(&self) -> Option<(&K, &V)> {
         self.values.lm_get(0).map(|(k, v)| (k, v))
     }

     /// Get the highest-rank key/value pair from the `LiteMap`, if it exists.
     ///
     /// # Examples
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map: LiteMap<i32, &str, Vec<_>> =
     ///     LiteMap::from_iter([(1, "uno"), (3, "tres")].into_iter());
     ///
     /// assert_eq!(map.last(), Some((&3, &"tres")));
     /// ```
     #[inline]
     pub fn last(&self) -> Option<(&K, &V)> {
         self.values.lm_get(self.len() - 1).map(|(k, v)| (k, v))
     }

     /// Obtain the index for a given key, or if the key is not found, the index
     /// at which it would be inserted.
     ///
     /// (The return value works equivalently to [`slice::binary_search_by()`])
     ///
     /// The indices returned can be used with [`Self::get_indexed()`]. Prefer using
     /// [`Self::get()`] directly where possible.
     #[inline]
     pub fn find_index<Q: ?Sized>(&self, key: &Q) -> Result<usize, usize>
     where
         K: Borrow<Q>,
         Q: Ord,
     {
         self.values.lm_binary_search_by(|k| k.borrow().cmp(key))
     }
 }

 impl<K, V, S> LiteMap<K, V, S>
 where
     S: StoreMut<K, V>,
 {
     /// Construct a new [`LiteMap`] with a given capacity
     pub fn with_capacity(capacity: usize) -> Self {
         Self {
             values: S::lm_with_capacity(capacity),
             _key_type: PhantomData,
             _value_type: PhantomData,
         }
     }

     /// Remove all elements from the [`LiteMap`]
     pub fn clear(&mut self) {
         self.values.lm_clear()
     }

     /// Reserve capacity for `additional` more elements to be inserted into
     /// the [`LiteMap`] to avoid frequent reallocations.
     ///
     /// See [`Vec::reserve()`] for more information.
     ///
     /// [`Vec::reserve()`]: alloc::vec::Vec::reserve
     pub fn reserve(&mut self, additional: usize) {
         self.values.lm_reserve(additional)
     }
 }

 impl<K, V, S> LiteMap<K, V, S>
 where
     K: Ord,
     S: StoreMut<K, V>,
 {
     /// Get the value associated with `key`, if it exists, as a mutable reference.
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// if let Some(mut v) = map.get_mut(&1) {
     ///     *v = "uno";
     /// }
     /// assert_eq!(map.get(&1), Some(&"uno"));
     /// ```
     pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V>
     where
         K: Borrow<Q>,
         Q: Ord,
     {
         match self.find_index(key) {
             #[allow(clippy::unwrap_used)] // find_index returns a valid index
             Ok(found) => Some(self.values.lm_get_mut(found).unwrap().1),
             Err(_) => None,
         }
     }

     /// Appends `value` with `key` to the end of the underlying vector, returning
     /// `key` and `value` _if it failed_. Useful for extending with an existing
     /// sorted list.
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// assert!(map.try_append(1, "uno").is_none());
     /// assert!(map.try_append(3, "tres").is_none());
     ///
     /// assert!(
     ///     matches!(map.try_append(3, "tres-updated"), Some((3, "tres-updated"))),
     ///     "append duplicate of last key",
     /// );
     ///
     /// assert!(
     ///     matches!(map.try_append(2, "dos"), Some((2, "dos"))),
     ///     "append out of order"
     /// );
     ///
     /// assert_eq!(map.get(&1), Some(&"uno"));
     ///
     /// // contains the original value for the key: 3
     /// assert_eq!(map.get(&3), Some(&"tres"));
     ///
     /// // not appended since it wasn't in order
     /// assert_eq!(map.get(&2), None);
     /// ```
     #[must_use]
     pub fn try_append(&mut self, key: K, value: V) -> Option<(K, V)> {
         if let Some(last) = self.values.lm_last() {
             if last.0 >= &key {
                 return Some((key, value));
             }
         }

         self.values.lm_push(key, value);
         None
     }

     /// Insert `value` with `key`, returning the existing value if it exists.
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// assert_eq!(map.get(&1), Some(&"one"));
     /// assert_eq!(map.get(&3), None);
     /// ```
     pub fn insert(&mut self, key: K, value: V) -> Option<V> {
         self.insert_save_key(key, value).map(|(_, v)| v)
     }

     /// Version of [`Self::insert()`] that returns both the key and the old value.
     fn insert_save_key(&mut self, key: K, value: V) -> Option<(K, V)> {
         match self.values.lm_binary_search_by(|k| k.cmp(&key)) {
             #[allow(clippy::unwrap_used)] // Index came from binary_search
             Ok(found) => Some((
                 key,
                 mem::replace(self.values.lm_get_mut(found).unwrap().1, value),
             )),
             Err(ins) => {
                 self.values.lm_insert(ins, key, value);
                 None
             }
         }
     }

     /// Attempts to insert a unique entry into the map.
     ///
     /// If `key` is not already in the map, inserts it with the corresponding `value`
     /// and returns `None`.
     ///
     /// If `key` is already in the map, no change is made to the map, and the key and value
     /// are returned back to the caller.
     ///
     /// ```
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(3, "three");
     ///
     /// // 2 is not yet in the map...
     /// assert_eq!(map.try_insert(2, "two"), None);
     /// assert_eq!(map.len(), 3);
     ///
     /// // ...but now it is.
     /// assert_eq!(map.try_insert(2, "TWO"), Some((2, "TWO")));
     /// assert_eq!(map.len(), 3);
     /// ```
     pub fn try_insert(&mut self, key: K, value: V) -> Option<(K, V)> {
         match self.values.lm_binary_search_by(|k| k.cmp(&key)) {
             Ok(_) => Some((key, value)),
             Err(ins) => {
                 self.values.lm_insert(ins, key, value);
                 None
             }
         }
     }

     /// Remove the value at `key`, returning it if it exists.
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// assert_eq!(map.remove(&1), Some("one"));
     /// assert_eq!(map.get(&1), None);
     /// ```
     pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V>
     where
         K: Borrow<Q>,
         Q: Ord,
     {
         match self.values.lm_binary_search_by(|k| k.borrow().cmp(key)) {
             Ok(found) => Some(self.values.lm_remove(found).1),
             Err(_) => None,
         }
     }
 }

 impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
 where
     K: Ord,
     S: StoreIterableMut<'a, K, V> + StoreFromIterator<K, V>,
 {
     /// Insert all elements from `other` into this `LiteMap`.
     ///
     /// If `other` contains keys that already exist in `self`, the values in `other` replace the
     /// corresponding ones in `self`, and the rejected items from `self` are returned as a new
     /// `LiteMap`. Otherwise, `None` is returned.
     ///
     /// The implementation of this function is optimized if `self` and `other` have no overlap.
     ///
     /// # Examples
     ///
     /// ```
     /// use litemap::LiteMap;
     ///
     /// let mut map1 = LiteMap::new_vec();
     /// map1.insert(1, "one");
     /// map1.insert(2, "two");
     ///
     /// let mut map2 = LiteMap::new_vec();
     /// map2.insert(2, "TWO");
     /// map2.insert(4, "FOUR");
     ///
     /// let leftovers = map1.extend_from_litemap(map2);
     ///
     /// assert_eq!(map1.len(), 3);
     /// assert_eq!(map1.get(&1), Some("one").as_ref());
     /// assert_eq!(map1.get(&2), Some("TWO").as_ref());
     /// assert_eq!(map1.get(&4), Some("FOUR").as_ref());
     ///
     /// let map3 = leftovers.expect("Duplicate keys");
     /// assert_eq!(map3.len(), 1);
     /// assert_eq!(map3.get(&2), Some("two").as_ref());
     /// ```
     pub fn extend_from_litemap(&mut self, other: Self) -> Option<Self> {
         if self.is_empty() {
             self.values = other.values;
             return None;
         }
         if other.is_empty() {
             return None;
         }
         if self.last().map(|(k, _)| k) < other.first().map(|(k, _)| k) {
             // append other to self
             self.values.lm_extend_end(other.values);
             None
         } else if self.first().map(|(k, _)| k) > other.last().map(|(k, _)| k) {
             // prepend other to self
             self.values.lm_extend_start(other.values);
             None
         } else {
             // insert every element
             let leftover_tuples = other
                 .values
                 .lm_into_iter()
                 .filter_map(|(k, v)| self.insert_save_key(k, v))
                 .collect();
             let ret = LiteMap {
                 values: leftover_tuples,
                 _key_type: PhantomData,
                 _value_type: PhantomData,
             };
             if ret.is_empty() {
                 None
             } else {
                 Some(ret)
             }
         }
     }
 }

 impl<K, V, S> Default for LiteMap<K, V, S>
 where
     S: Store<K, V> + Default,
 {
     fn default() -> Self {
         Self {
             values: S::default(),
             _key_type: PhantomData,
             _value_type: PhantomData,
         }
     }
 }
 impl<K, V, S> Index<&'_ K> for LiteMap<K, V, S>
 where
     K: Ord,
     S: Store<K, V>,
 {
     type Output = V;
     fn index(&self, key: &K) -> &V {
         #[allow(clippy::panic)] // documented
         match self.get(key) {
             Some(v) => v,
             None => panic!("no entry found for key"),
         }
     }
 }
 impl<K, V, S> IndexMut<&'_ K> for LiteMap<K, V, S>
 where
     K: Ord,
     S: StoreMut<K, V>,
 {
     fn index_mut(&mut self, key: &K) -> &mut V {
         #[allow(clippy::panic)] // documented
         match self.get_mut(key) {
             Some(v) => v,
             None => panic!("no entry found for key"),
         }
     }
 }
 impl<K, V, S> FromIterator<(K, V)> for LiteMap<K, V, S>
 where
     K: Ord,
     S: StoreFromIterable<K, V>,
 {
     fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self {
         let values = S::lm_sort_from_iter(iter);
         Self::from_sorted_store_unchecked(values)
     }
 }

 impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
 where
     S: StoreIterable<'a, K, V>,
 {
     /// Produce an ordered iterator over key-value pairs
     pub fn iter(&'a self) -> impl Iterator<Item = (&'a K, &'a V)> + DoubleEndedIterator {
         self.values.lm_iter()
     }

     /// Produce an ordered iterator over keys
     pub fn iter_keys(&'a self) -> impl Iterator<Item = &'a K> + DoubleEndedIterator {
         self.values.lm_iter().map(|val| val.0)
     }

     /// Produce an iterator over values, ordered by their keys
     pub fn iter_values(&'a self) -> impl Iterator<Item = &'a V> + DoubleEndedIterator {
         self.values.lm_iter().map(|val| val.1)
     }
 }

 impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
 where
     S: StoreIterableMut<'a, K, V>,
 {
     /// Produce an ordered mutable iterator over key-value pairs
     pub fn iter_mut(
         &'a mut self,
     ) -> impl Iterator<Item = (&'a K, &'a mut V)> + DoubleEndedIterator {
         self.values.lm_iter_mut()
     }
 }

 impl<K, V, S> LiteMap<K, V, S>
 where
     S: StoreMut<K, V>,
 {
     /// Retains only the elements specified by the predicate.
     ///
     /// In other words, remove all elements such that `f((&k, &v))` returns `false`.
     ///
     /// # Example
     ///
     /// ```rust
     /// use litemap::LiteMap;
     ///
     /// let mut map = LiteMap::new_vec();
     /// map.insert(1, "one");
     /// map.insert(2, "two");
     /// map.insert(3, "three");
     ///
     /// // Retain elements with odd keys
     /// map.retain(|k, _| k % 2 == 1);
     ///
     /// assert_eq!(map.get(&1), Some(&"one"));
     /// assert_eq!(map.get(&2), None);
     /// ```
     #[inline]
     pub fn retain<F>(&mut self, predicate: F)
     where
         F: FnMut(&K, &V) -> bool,
     {
         self.values.lm_retain(predicate)
     }
 }

 #[cfg(test)]
 mod test {
     use crate::LiteMap;

     #[test]
     fn from_iterator() {
         let mut expected = LiteMap::with_capacity(4);
         expected.insert(1, "updated-one");
         expected.insert(2, "original-two");
         expected.insert(3, "original-three");
         expected.insert(4, "updated-four");

         let actual = vec![
             (1, "original-one"),
             (2, "original-two"),
             (4, "original-four"),
             (4, "updated-four"),
             (1, "updated-one"),
             (3, "original-three"),
         ]
         .into_iter()
         .collect::<LiteMap<_, _>>();

         assert_eq!(expected, actual);
     }
     fn make_13() -> LiteMap<usize, &'static str> {
         let mut result = LiteMap::new();
         result.insert(1, "one");
         result.insert(3, "three");
         result
     }

     fn make_24() -> LiteMap<usize, &'static str> {
         let mut result = LiteMap::new();
         result.insert(2, "TWO");
         result.insert(4, "FOUR");
         result
     }

     fn make_46() -> LiteMap<usize, &'static str> {
         let mut result = LiteMap::new();
         result.insert(4, "four");
         result.insert(6, "six");
         result
     }

     #[test]
     fn extend_from_litemap_append() {
         let mut map = LiteMap::new();
         map.extend_from_litemap(make_13())
             .ok_or(())
             .expect_err("Append to empty map");
         map.extend_from_litemap(make_46())
             .ok_or(())
             .expect_err("Append to lesser map");
         assert_eq!(map.len(), 4);
     }

     #[test]
     fn extend_from_litemap_prepend() {
         let mut map = LiteMap::new();
         map.extend_from_litemap(make_46())
             .ok_or(())
             .expect_err("Prepend to empty map");
         map.extend_from_litemap(make_13())
             .ok_or(())
             .expect_err("Prepend to lesser map");
         assert_eq!(map.len(), 4);
     }

     #[test]
     fn extend_from_litemap_insert() {
         let mut map = LiteMap::new();
         map.extend_from_litemap(make_13())
             .ok_or(())
             .expect_err("Append to empty map");
         map.extend_from_litemap(make_24())
             .ok_or(())
             .expect_err("Insert with no conflict");
         map.extend_from_litemap(make_46())
             .ok_or(())
             .expect("Insert with conflict");
         assert_eq!(map.len(), 5);
     }
 }
	// This file is part of ICU4X. For terms of use, please see the file
	// called LICENSE at the top level of the ICU4X source tree
	// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

	use crate::store::*;
	use alloc::borrow::Borrow;
	use alloc::vec::Vec;
	use core::cmp::Ordering;
	use core::iter::FromIterator;
	use core::marker::PhantomData;
	use core::mem;
	use core::ops::{Index, IndexMut};

	/// A simple "flat" map based on a sorted vector
	///
	/// See the [module level documentation][super] for why one should use this.
	///
	/// The API is roughly similar to that of [`std::collections::BTreeMap`].
	#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
	#[cfg_attr(feature = "yoke", derive(yoke::Yokeable))]
	pub struct LiteMap<K: ?Sized, V: ?Sized, S = alloc::vec::Vec<(K, V)>> {
	pub(crate) values: S,
	pub(crate) _key_type: PhantomData<K>,
	pub(crate) _value_type: PhantomData<V>,
	}

	impl<K, V> LiteMap<K, V> {
	/// Construct a new [`LiteMap`] backed by Vec
	pub const fn new_vec() -> Self {
	Self {
	values: alloc::vec::Vec::new(),
	_key_type: PhantomData,
	_value_type: PhantomData,
	}
	}
	}

	impl<K, V, S> LiteMap<K, V, S> {
	/// Construct a new [`LiteMap`] using the given values
	///
	/// The store must be sorted and have no duplicate keys.
	pub const fn from_sorted_store_unchecked(values: S) -> Self {
	Self {
	values,
	_key_type: PhantomData,
	_value_type: PhantomData,
	}
	}
	}

	impl<K, V> LiteMap<K, V, Vec<(K, V)>> {
	/// Convert a [`LiteMap`] into a sorted `Vec<(K, V)>`.
	#[inline]
	pub fn into_tuple_vec(self) -> Vec<(K, V)> {
	self.values
	}
	}

	impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
	where
	S: StoreConstEmpty<K, V>,
	{
	/// Create a new empty [`LiteMap`]
	pub const fn new() -> Self {
	Self {
	values: S::EMPTY,
	_key_type: PhantomData,
	_value_type: PhantomData,
	}
	}
	}

	impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
	where
	S: Store<K, V>,
	{
	/// The number of elements in the [`LiteMap`]
	pub fn len(&self) -> usize {
	self.values.lm_len()
	}

	/// Whether the [`LiteMap`] is empty
	pub fn is_empty(&self) -> bool {
	self.values.lm_is_empty()
	}

	/// Get the key-value pair residing at a particular index
	///
	/// In most cases, prefer [`LiteMap::get()`] over this method.
	#[inline]
	pub fn get_indexed(&self, index: usize) -> Option<(&K, &V)> {
	self.values.lm_get(index)
	}
	}

	impl<K: ?Sized, V: ?Sized, S> LiteMap<K, V, S>
	where
	K: Ord,
	S: Store<K, V>,
	{
	/// Get the value associated with `key`, if it exists.
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// assert_eq!(map.get(&1), Some(&"one"));
	/// assert_eq!(map.get(&3), None);
	/// ```
	pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V>
	where
	K: Borrow<Q>,
	Q: Ord,
	{
	match self.find_index(key) {
	#[allow(clippy::unwrap_used)] // find_index returns a valid index
	Ok(found) => Some(self.values.lm_get(found).unwrap().1),
	Err(_) => None,
	}
	}

	/// Binary search the map with `predicate` to find a key, returning the value.
	pub fn get_by(&self, predicate: impl FnMut(&K) -> Ordering) -> Option<&V> {
	let index = self.values.lm_binary_search_by(predicate).ok()?;
	self.values.lm_get(index).map(\|(_, v)\| v)
	}

	/// Returns whether `key` is contained in this map
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// assert!(map.contains_key(&1));
	/// assert!(!map.contains_key(&3));
	/// ```
	pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool
	where
	K: Borrow<Q>,
	Q: Ord,
	{
	self.find_index(key).is_ok()
	}

	/// Get the lowest-rank key/value pair from the `LiteMap`, if it exists.
	///
	/// # Examples
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map: LiteMap<i32, &str, Vec<_>> =
	/// LiteMap::from_iter([(1, "uno"), (3, "tres")].into_iter());
	///
	/// assert_eq!(map.first(), Some((&1, &"uno")));
	/// ```
	#[inline]
	pub fn first(&self) -> Option<(&K, &V)> {
	self.values.lm_get(0).map(\|(k, v)\| (k, v))
	}

	/// Get the highest-rank key/value pair from the `LiteMap`, if it exists.
	///
	/// # Examples
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map: LiteMap<i32, &str, Vec<_>> =
	/// LiteMap::from_iter([(1, "uno"), (3, "tres")].into_iter());
	///
	/// assert_eq!(map.last(), Some((&3, &"tres")));
	/// ```
	#[inline]
	pub fn last(&self) -> Option<(&K, &V)> {
	self.values.lm_get(self.len() - 1).map(\|(k, v)\| (k, v))
	}

	/// Obtain the index for a given key, or if the key is not found, the index
	/// at which it would be inserted.
	///
	/// (The return value works equivalently to [`slice::binary_search_by()`])
	///
	/// The indices returned can be used with [`Self::get_indexed()`]. Prefer using
	/// [`Self::get()`] directly where possible.
	#[inline]
	pub fn find_index<Q: ?Sized>(&self, key: &Q) -> Result<usize, usize>
	where
	K: Borrow<Q>,
	Q: Ord,
	{
	self.values.lm_binary_search_by(\|k\| k.borrow().cmp(key))
	}
	}

	impl<K, V, S> LiteMap<K, V, S>
	where
	S: StoreMut<K, V>,
	{
	/// Construct a new [`LiteMap`] with a given capacity
	pub fn with_capacity(capacity: usize) -> Self {
	Self {
	values: S::lm_with_capacity(capacity),
	_key_type: PhantomData,
	_value_type: PhantomData,
	}
	}

	/// Remove all elements from the [`LiteMap`]
	pub fn clear(&mut self) {
	self.values.lm_clear()
	}

	/// Reserve capacity for `additional` more elements to be inserted into
	/// the [`LiteMap`] to avoid frequent reallocations.
	///
	/// See [`Vec::reserve()`] for more information.
	///
	/// [`Vec::reserve()`]: alloc::vec::Vec::reserve
	pub fn reserve(&mut self, additional: usize) {
	self.values.lm_reserve(additional)
	}
	}

	impl<K, V, S> LiteMap<K, V, S>
	where
	K: Ord,
	S: StoreMut<K, V>,
	{
	/// Get the value associated with `key`, if it exists, as a mutable reference.
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// if let Some(mut v) = map.get_mut(&1) {
	/// *v = "uno";
	/// }
	/// assert_eq!(map.get(&1), Some(&"uno"));
	/// ```
	pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V>
	where
	K: Borrow<Q>,
	Q: Ord,
	{
	match self.find_index(key) {
	#[allow(clippy::unwrap_used)] // find_index returns a valid index
	Ok(found) => Some(self.values.lm_get_mut(found).unwrap().1),
	Err(_) => None,
	}
	}

	/// Appends `value` with `key` to the end of the underlying vector, returning
	/// `key` and `value` _if it failed_. Useful for extending with an existing
	/// sorted list.
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// assert!(map.try_append(1, "uno").is_none());
	/// assert!(map.try_append(3, "tres").is_none());
	///
	/// assert!(
	/// matches!(map.try_append(3, "tres-updated"), Some((3, "tres-updated"))),
	/// "append duplicate of last key",
	/// );
	///
	/// assert!(
	/// matches!(map.try_append(2, "dos"), Some((2, "dos"))),
	/// "append out of order"
	/// );
	///
	/// assert_eq!(map.get(&1), Some(&"uno"));
	///
	/// // contains the original value for the key: 3
	/// assert_eq!(map.get(&3), Some(&"tres"));
	///
	/// // not appended since it wasn't in order
	/// assert_eq!(map.get(&2), None);
	/// ```
	#[must_use]
	pub fn try_append(&mut self, key: K, value: V) -> Option<(K, V)> {
	if let Some(last) = self.values.lm_last() {
	if last.0 >= &key {
	return Some((key, value));
	}
	}

	self.values.lm_push(key, value);
	None
	}

	/// Insert `value` with `key`, returning the existing value if it exists.
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// assert_eq!(map.get(&1), Some(&"one"));
	/// assert_eq!(map.get(&3), None);
	/// ```
	pub fn insert(&mut self, key: K, value: V) -> Option<V> {
	self.insert_save_key(key, value).map(\|(_, v)\| v)
	}

	/// Version of [`Self::insert()`] that returns both the key and the old value.
	fn insert_save_key(&mut self, key: K, value: V) -> Option<(K, V)> {
	match self.values.lm_binary_search_by(\|k\| k.cmp(&key)) {
	#[allow(clippy::unwrap_used)] // Index came from binary_search
	Ok(found) => Some((
	key,
	mem::replace(self.values.lm_get_mut(found).unwrap().1, value),
	)),
	Err(ins) => {
	self.values.lm_insert(ins, key, value);
	None
	}
	}
	}

	/// Attempts to insert a unique entry into the map.
	///
	/// If `key` is not already in the map, inserts it with the corresponding `value`
	/// and returns `None`.
	///
	/// If `key` is already in the map, no change is made to the map, and the key and value
	/// are returned back to the caller.
	///
	/// ```
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(3, "three");
	///
	/// // 2 is not yet in the map...
	/// assert_eq!(map.try_insert(2, "two"), None);
	/// assert_eq!(map.len(), 3);
	///
	/// // ...but now it is.
	/// assert_eq!(map.try_insert(2, "TWO"), Some((2, "TWO")));
	/// assert_eq!(map.len(), 3);
	/// ```
	pub fn try_insert(&mut self, key: K, value: V) -> Option<(K, V)> {
	match self.values.lm_binary_search_by(\|k\| k.cmp(&key)) {
	Ok(_) => Some((key, value)),
	Err(ins) => {
	self.values.lm_insert(ins, key, value);
	None
	}
	}
	}

	/// Remove the value at `key`, returning it if it exists.
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// assert_eq!(map.remove(&1), Some("one"));
	/// assert_eq!(map.get(&1), None);
	/// ```
	pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V>
	where
	K: Borrow<Q>,
	Q: Ord,
	{
	match self.values.lm_binary_search_by(\|k\| k.borrow().cmp(key)) {
	Ok(found) => Some(self.values.lm_remove(found).1),
	Err(_) => None,
	}
	}
	}

	impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
	where
	K: Ord,
	S: StoreIterableMut<'a, K, V> + StoreFromIterator<K, V>,
	{
	/// Insert all elements from `other` into this `LiteMap`.
	///
	/// If `other` contains keys that already exist in `self`, the values in `other` replace the
	/// corresponding ones in `self`, and the rejected items from `self` are returned as a new
	/// `LiteMap`. Otherwise, `None` is returned.
	///
	/// The implementation of this function is optimized if `self` and `other` have no overlap.
	///
	/// # Examples
	///
	/// ```
	/// use litemap::LiteMap;
	///
	/// let mut map1 = LiteMap::new_vec();
	/// map1.insert(1, "one");
	/// map1.insert(2, "two");
	///
	/// let mut map2 = LiteMap::new_vec();
	/// map2.insert(2, "TWO");
	/// map2.insert(4, "FOUR");
	///
	/// let leftovers = map1.extend_from_litemap(map2);
	///
	/// assert_eq!(map1.len(), 3);
	/// assert_eq!(map1.get(&1), Some("one").as_ref());
	/// assert_eq!(map1.get(&2), Some("TWO").as_ref());
	/// assert_eq!(map1.get(&4), Some("FOUR").as_ref());
	///
	/// let map3 = leftovers.expect("Duplicate keys");
	/// assert_eq!(map3.len(), 1);
	/// assert_eq!(map3.get(&2), Some("two").as_ref());
	/// ```
	pub fn extend_from_litemap(&mut self, other: Self) -> Option<Self> {
	if self.is_empty() {
	self.values = other.values;
	return None;
	}
	if other.is_empty() {
	return None;
	}
	if self.last().map(\|(k, _)\| k) < other.first().map(\|(k, _)\| k) {
	// append other to self
	self.values.lm_extend_end(other.values);
	None
	} else if self.first().map(\|(k, _)\| k) > other.last().map(\|(k, _)\| k) {
	// prepend other to self
	self.values.lm_extend_start(other.values);
	None
	} else {
	// insert every element
	let leftover_tuples = other
	.values
	.lm_into_iter()
	.filter_map(\|(k, v)\| self.insert_save_key(k, v))
	.collect();
	let ret = LiteMap {
	values: leftover_tuples,
	_key_type: PhantomData,
	_value_type: PhantomData,
	};
	if ret.is_empty() {
	None
	} else {
	Some(ret)
	}
	}
	}
	}

	impl<K, V, S> Default for LiteMap<K, V, S>
	where
	S: Store<K, V> + Default,
	{
	fn default() -> Self {
	Self {
	values: S::default(),
	_key_type: PhantomData,
	_value_type: PhantomData,
	}
	}
	}
	impl<K, V, S> Index<&'_ K> for LiteMap<K, V, S>
	where
	K: Ord,
	S: Store<K, V>,
	{
	type Output = V;
	fn index(&self, key: &K) -> &V {
	#[allow(clippy::panic)] // documented
	match self.get(key) {
	Some(v) => v,
	None => panic!("no entry found for key"),
	}
	}
	}
	impl<K, V, S> IndexMut<&'_ K> for LiteMap<K, V, S>
	where
	K: Ord,
	S: StoreMut<K, V>,
	{
	fn index_mut(&mut self, key: &K) -> &mut V {
	#[allow(clippy::panic)] // documented
	match self.get_mut(key) {
	Some(v) => v,
	None => panic!("no entry found for key"),
	}
	}
	}
	impl<K, V, S> FromIterator<(K, V)> for LiteMap<K, V, S>
	where
	K: Ord,
	S: StoreFromIterable<K, V>,
	{
	fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self {
	let values = S::lm_sort_from_iter(iter);
	Self::from_sorted_store_unchecked(values)
	}
	}

	impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
	where
	S: StoreIterable<'a, K, V>,
	{
	/// Produce an ordered iterator over key-value pairs
	pub fn iter(&'a self) -> impl Iterator<Item = (&'a K, &'a V)> + DoubleEndedIterator {
	self.values.lm_iter()
	}

	/// Produce an ordered iterator over keys
	pub fn iter_keys(&'a self) -> impl Iterator<Item = &'a K> + DoubleEndedIterator {
	self.values.lm_iter().map(\|val\| val.0)
	}

	/// Produce an iterator over values, ordered by their keys
	pub fn iter_values(&'a self) -> impl Iterator<Item = &'a V> + DoubleEndedIterator {
	self.values.lm_iter().map(\|val\| val.1)
	}
	}

	impl<'a, K: 'a, V: 'a, S> LiteMap<K, V, S>
	where
	S: StoreIterableMut<'a, K, V>,
	{
	/// Produce an ordered mutable iterator over key-value pairs
	pub fn iter_mut(
	&'a mut self,
	) -> impl Iterator<Item = (&'a K, &'a mut V)> + DoubleEndedIterator {
	self.values.lm_iter_mut()
	}
	}

	impl<K, V, S> LiteMap<K, V, S>
	where
	S: StoreMut<K, V>,
	{
	/// Retains only the elements specified by the predicate.
	///
	/// In other words, remove all elements such that `f((&k, &v))` returns `false`.
	///
	/// # Example
	///
	/// ```rust
	/// use litemap::LiteMap;
	///
	/// let mut map = LiteMap::new_vec();
	/// map.insert(1, "one");
	/// map.insert(2, "two");
	/// map.insert(3, "three");
	///
	/// // Retain elements with odd keys
	/// map.retain(\|k, _\| k % 2 == 1);
	///
	/// assert_eq!(map.get(&1), Some(&"one"));
	/// assert_eq!(map.get(&2), None);
	/// ```
	#[inline]
	pub fn retain<F>(&mut self, predicate: F)
	where
	F: FnMut(&K, &V) -> bool,
	{
	self.values.lm_retain(predicate)
	}
	}

	#[cfg(test)]
	mod test {
	use crate::LiteMap;

	#[test]
	fn from_iterator() {
	let mut expected = LiteMap::with_capacity(4);
	expected.insert(1, "updated-one");
	expected.insert(2, "original-two");
	expected.insert(3, "original-three");
	expected.insert(4, "updated-four");

	let actual = vec![
	(1, "original-one"),
	(2, "original-two"),
	(4, "original-four"),
	(4, "updated-four"),
	(1, "updated-one"),
	(3, "original-three"),
	]
	.into_iter()
	.collect::<LiteMap<_, _>>();

	assert_eq!(expected, actual);
	}
	fn make_13() -> LiteMap<usize, &'static str> {
	let mut result = LiteMap::new();
	result.insert(1, "one");
	result.insert(3, "three");
	result
	}

	fn make_24() -> LiteMap<usize, &'static str> {
	let mut result = LiteMap::new();
	result.insert(2, "TWO");
	result.insert(4, "FOUR");
	result
	}

	fn make_46() -> LiteMap<usize, &'static str> {
	let mut result = LiteMap::new();
	result.insert(4, "four");
	result.insert(6, "six");
	result
	}

	#[test]
	fn extend_from_litemap_append() {
	let mut map = LiteMap::new();
	map.extend_from_litemap(make_13())
	.ok_or(())
	.expect_err("Append to empty map");
	map.extend_from_litemap(make_46())
	.ok_or(())
	.expect_err("Append to lesser map");
	assert_eq!(map.len(), 4);
	}

	#[test]
	fn extend_from_litemap_prepend() {
	let mut map = LiteMap::new();
	map.extend_from_litemap(make_46())
	.ok_or(())
	.expect_err("Prepend to empty map");
	map.extend_from_litemap(make_13())
	.ok_or(())
	.expect_err("Prepend to lesser map");
	assert_eq!(map.len(), 4);
	}

	#[test]
	fn extend_from_litemap_insert() {
	let mut map = LiteMap::new();
	map.extend_from_litemap(make_13())
	.ok_or(())
	.expect_err("Append to empty map");
	map.extend_from_litemap(make_24())
	.ok_or(())
	.expect_err("Insert with no conflict");
	map.extend_from_litemap(make_46())
	.ok_or(())
	.expect("Insert with conflict");
	assert_eq!(map.len(), 5);
	}
	}