diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs index b585e2082f1..2b8ddf14ff3 100644 --- a/library/alloc/src/collections/btree/map.rs +++ b/library/alloc/src/collections/btree/map.rs @@ -2522,10 +2522,17 @@ pub const fn is_empty(&self) -> bool { self.len() == 0 } - /// Returns a [`Cursor`] pointing to the first gap above the given bound. + /// Returns a [`Cursor`] pointing at the gap before the smallest key + /// greater than the given bound. /// - /// Passing [`Bound::Unbounded`] will return a cursor pointing to the start - /// of the map. + /// Passing `Bound::Included(x)` will return a cursor pointing to the + /// gap before the smallest key greater than or equal to `x`. + /// + /// Passing `Bound::Excluded(x)` will return a cursor pointing to the + /// gap before the smallest key greater than `x`. + /// + /// Passing `Bound::Unbounded` will return a cursor pointing to the + /// gap before the smallest key in the map. /// /// # Examples /// @@ -2535,17 +2542,24 @@ pub const fn is_empty(&self) -> bool { /// use std::collections::BTreeMap; /// use std::ops::Bound; /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// a.insert(4, "d"); - /// let cursor = a.lower_bound(Bound::Included(&2)); + /// let map = BTreeMap::from([ + /// (1, "a"), + /// (2, "b"), + /// (3, "c"), + /// (4, "d"), + /// ]); + /// + /// let cursor = map.lower_bound(Bound::Included(&2)); /// assert_eq!(cursor.peek_prev(), Some((&1, &"a"))); /// assert_eq!(cursor.peek_next(), Some((&2, &"b"))); - /// let cursor = a.lower_bound(Bound::Excluded(&2)); + /// + /// let cursor = map.lower_bound(Bound::Excluded(&2)); /// assert_eq!(cursor.peek_prev(), Some((&2, &"b"))); /// assert_eq!(cursor.peek_next(), Some((&3, &"c"))); + /// + /// let cursor = map.lower_bound(Bound::Unbounded); + /// assert_eq!(cursor.peek_prev(), None); + /// assert_eq!(cursor.peek_next(), Some((&1, &"a"))); /// ``` #[unstable(feature = "btree_cursors", issue = "107540")] pub fn lower_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> @@ -2561,11 +2575,17 @@ pub fn lower_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> Cursor { current: Some(edge), root: self.root.as_ref() } } - /// Returns a [`CursorMut`] pointing to the first gap above the given bound. + /// Returns a [`CursorMut`] pointing at the gap before the smallest key + /// greater than the given bound. /// + /// Passing `Bound::Included(x)` will return a cursor pointing to the + /// gap before the smallest key greater than or equal to `x`. /// - /// Passing [`Bound::Unbounded`] will return a cursor pointing to the start - /// of the map. + /// Passing `Bound::Excluded(x)` will return a cursor pointing to the + /// gap before the smallest key greater than `x`. + /// + /// Passing `Bound::Unbounded` will return a cursor pointing to the + /// gap before the smallest key in the map. /// /// # Examples /// @@ -2575,17 +2595,24 @@ pub fn lower_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> /// use std::collections::BTreeMap; /// use std::ops::Bound; /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// a.insert(4, "d"); - /// let mut cursor = a.lower_bound_mut(Bound::Included(&2)); + /// let mut map = BTreeMap::from([ + /// (1, "a"), + /// (2, "b"), + /// (3, "c"), + /// (4, "d"), + /// ]); + /// + /// let mut cursor = map.lower_bound_mut(Bound::Included(&2)); /// assert_eq!(cursor.peek_prev(), Some((&1, &mut "a"))); /// assert_eq!(cursor.peek_next(), Some((&2, &mut "b"))); - /// let mut cursor = a.lower_bound_mut(Bound::Excluded(&2)); + /// + /// let mut cursor = map.lower_bound_mut(Bound::Excluded(&2)); /// assert_eq!(cursor.peek_prev(), Some((&2, &mut "b"))); /// assert_eq!(cursor.peek_next(), Some((&3, &mut "c"))); + /// + /// let mut cursor = map.lower_bound_mut(Bound::Unbounded); + /// assert_eq!(cursor.peek_prev(), None); + /// assert_eq!(cursor.peek_next(), Some((&1, &mut "a"))); /// ``` #[unstable(feature = "btree_cursors", issue = "107540")] pub fn lower_bound_mut(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A> @@ -2618,10 +2645,17 @@ pub fn lower_bound_mut(&mut self, bound: Bound<&Q>) -> CursorMut<'_, } } - /// Returns a [`Cursor`] pointing at the last gap below the given bound. + /// Returns a [`Cursor`] pointing at the gap after the greatest key + /// smaller than the given bound. /// - /// Passing [`Bound::Unbounded`] will return a cursor pointing to the end - /// of the map. + /// Passing `Bound::Included(x)` will return a cursor pointing to the + /// gap after the greatest key smaller than or equal to `x`. + /// + /// Passing `Bound::Excluded(x)` will return a cursor pointing to the + /// gap after the greatest key smaller than `x`. + /// + /// Passing `Bound::Unbounded` will return a cursor pointing to the + /// gap after the greatest key in the map. /// /// # Examples /// @@ -2631,17 +2665,24 @@ pub fn lower_bound_mut(&mut self, bound: Bound<&Q>) -> CursorMut<'_, /// use std::collections::BTreeMap; /// use std::ops::Bound; /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// a.insert(4, "d"); - /// let cursor = a.upper_bound(Bound::Included(&3)); + /// let map = BTreeMap::from([ + /// (1, "a"), + /// (2, "b"), + /// (3, "c"), + /// (4, "d"), + /// ]); + /// + /// let cursor = map.upper_bound(Bound::Included(&3)); /// assert_eq!(cursor.peek_prev(), Some((&3, &"c"))); /// assert_eq!(cursor.peek_next(), Some((&4, &"d"))); - /// let cursor = a.upper_bound(Bound::Excluded(&3)); + /// + /// let cursor = map.upper_bound(Bound::Excluded(&3)); /// assert_eq!(cursor.peek_prev(), Some((&2, &"b"))); /// assert_eq!(cursor.peek_next(), Some((&3, &"c"))); + /// + /// let cursor = map.upper_bound(Bound::Unbounded); + /// assert_eq!(cursor.peek_prev(), Some((&4, &"d"))); + /// assert_eq!(cursor.peek_next(), None); /// ``` #[unstable(feature = "btree_cursors", issue = "107540")] pub fn upper_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> @@ -2657,10 +2698,17 @@ pub fn upper_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> Cursor { current: Some(edge), root: self.root.as_ref() } } - /// Returns a [`CursorMut`] pointing at the last gap below the given bound. + /// Returns a [`CursorMut`] pointing at the gap after the greatest key + /// smaller than the given bound. /// - /// Passing [`Bound::Unbounded`] will return a cursor pointing to the end - /// of the map. + /// Passing `Bound::Included(x)` will return a cursor pointing to the + /// gap after the greatest key smaller than or equal to `x`. + /// + /// Passing `Bound::Excluded(x)` will return a cursor pointing to the + /// gap after the greatest key smaller than `x`. + /// + /// Passing `Bound::Unbounded` will return a cursor pointing to the + /// gap after the greatest key in the map. /// /// # Examples /// @@ -2670,17 +2718,24 @@ pub fn upper_bound(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> /// use std::collections::BTreeMap; /// use std::ops::Bound; /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// a.insert(4, "d"); - /// let mut cursor = a.upper_bound_mut(Bound::Included(&3)); + /// let mut map = BTreeMap::from([ + /// (1, "a"), + /// (2, "b"), + /// (3, "c"), + /// (4, "d"), + /// ]); + /// + /// let mut cursor = map.upper_bound_mut(Bound::Included(&3)); /// assert_eq!(cursor.peek_prev(), Some((&3, &mut "c"))); /// assert_eq!(cursor.peek_next(), Some((&4, &mut "d"))); - /// let mut cursor = a.upper_bound_mut(Bound::Excluded(&3)); + /// + /// let mut cursor = map.upper_bound_mut(Bound::Excluded(&3)); /// assert_eq!(cursor.peek_prev(), Some((&2, &mut "b"))); /// assert_eq!(cursor.peek_next(), Some((&3, &mut "c"))); + /// + /// let mut cursor = map.upper_bound_mut(Bound::Unbounded); + /// assert_eq!(cursor.peek_prev(), Some((&4, &mut "d"))); + /// assert_eq!(cursor.peek_next(), None); /// ``` #[unstable(feature = "btree_cursors", issue = "107540")] pub fn upper_bound_mut(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A> @@ -3040,8 +3095,8 @@ pub fn as_cursor(&self) -> Cursor<'_, K, V> { // Now the tree editing operations impl<'a, K: Ord, V, A: Allocator + Clone> CursorMutKey<'a, K, V, A> { - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMutKey` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap before the /// newly inserted element. @@ -3083,8 +3138,8 @@ pub unsafe fn insert_after_unchecked(&mut self, key: K, value: V) { *self.length += 1; } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMutKey` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap after the /// newly inserted element. @@ -3129,19 +3184,16 @@ pub unsafe fn insert_before_unchecked(&mut self, key: K, value: V) { *self.length += 1; } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMutKey` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap before the /// newly inserted element. /// - /// # Panics - /// - /// This function panics if: - /// - the given key compares less than or equal to the current element (if - /// any). - /// - the given key compares greater than or equal to the next element (if - /// any). + /// If the inserted key is not greater than the key before the cursor + /// (if any), or if it not less than the key after the cursor (if any), + /// then an [`UnorderedKeyError`] is returned since this would + /// invalidate the [`Ord`] invariant between the keys of the map. #[unstable(feature = "btree_cursors", issue = "107540")] pub fn insert_after(&mut self, key: K, value: V) -> Result<(), UnorderedKeyError> { if let Some((prev, _)) = self.peek_prev() { @@ -3160,19 +3212,16 @@ pub fn insert_after(&mut self, key: K, value: V) -> Result<(), UnorderedKeyError Ok(()) } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMutKey` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap after the /// newly inserted element. /// - /// # Panics - /// - /// This function panics if: - /// - the given key compares greater than or equal to the current element - /// (if any). - /// - the given key compares less than or equal to the previous element (if - /// any). + /// If the inserted key is not greater than the key before the cursor + /// (if any), or if it not less than the key after the cursor (if any), + /// then an [`UnorderedKeyError`] is returned since this would + /// invalidate the [`Ord`] invariant between the keys of the map. #[unstable(feature = "btree_cursors", issue = "107540")] pub fn insert_before(&mut self, key: K, value: V) -> Result<(), UnorderedKeyError> { if let Some((prev, _)) = self.peek_prev() { @@ -3239,10 +3288,10 @@ pub fn remove_prev(&mut self) -> Option<(K, V)> { } impl<'a, K: Ord, V, A: Allocator + Clone> CursorMut<'a, K, V, A> { - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMut` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// - /// After the insertion the cursor will be pointing at the gap before the + /// After the insertion the cursor will be pointing at the gap after the /// newly inserted element. /// /// # Safety @@ -3257,8 +3306,8 @@ pub unsafe fn insert_after_unchecked(&mut self, key: K, value: V) { unsafe { self.inner.insert_after_unchecked(key, value) } } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMut` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap after the /// newly inserted element. @@ -3275,37 +3324,31 @@ pub unsafe fn insert_before_unchecked(&mut self, key: K, value: V) { unsafe { self.inner.insert_before_unchecked(key, value) } } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMut` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap before the /// newly inserted element. /// - /// # Panics - /// - /// This function panics if: - /// - the given key compares less than or equal to the current element (if - /// any). - /// - the given key compares greater than or equal to the next element (if - /// any). + /// If the inserted key is not greater than the key before the cursor + /// (if any), or if it not less than the key after the cursor (if any), + /// then an [`UnorderedKeyError`] is returned since this would + /// invalidate the [`Ord`] invariant between the keys of the map. #[unstable(feature = "btree_cursors", issue = "107540")] pub fn insert_after(&mut self, key: K, value: V) -> Result<(), UnorderedKeyError> { self.inner.insert_after(key, value) } - /// Inserts a new element into the `BTreeMap` in the gap that the - /// `CursorMut` is currently pointing to. + /// Inserts a new key-value pair into the map in the gap that the + /// cursor is currently pointing to. /// /// After the insertion the cursor will be pointing at the gap after the /// newly inserted element. /// - /// # Panics - /// - /// This function panics if: - /// - the given key compares greater than or equal to the current element - /// (if any). - /// - the given key compares less than or equal to the previous element (if - /// any). + /// If the inserted key is not greater than the key before the cursor + /// (if any), or if it not less than the key after the cursor (if any), + /// then an [`UnorderedKeyError`] is returned since this would + /// invalidate the [`Ord`] invariant between the keys of the map. #[unstable(feature = "btree_cursors", issue = "107540")] pub fn insert_before(&mut self, key: K, value: V) -> Result<(), UnorderedKeyError> { self.inner.insert_before(key, value)