[stdlib] Add custom implementations of removeLast and remove(at:) to Array (#14212)
* Add custom implementations of removeLast and remove(at:) to Array
diff --git a/stdlib/public/core/Arrays.swift.gyb b/stdlib/public/core/Arrays.swift.gyb
index eaf1f5e..d6e9097 100644
--- a/stdlib/public/core/Arrays.swift.gyb
+++ b/stdlib/public/core/Arrays.swift.gyb
@@ -1493,17 +1493,6 @@
}
%if Self == 'ArraySlice':
- /// Removes and returns the last element of the array.
- ///
- /// The array must not be empty. This example removes the last number from an
- /// array of `Double` values.
- ///
- /// var measurements: [Double] = [1.1, 1.5, 2.9, 1.2, 1.5, 1.3, 1.2]
- /// let removed = measurements.removeLast()
- /// print(measurements)
- /// // Prints "[1.1, 1.5, 2.9, 1.2, 1.5, 1.3]"
- ///
- /// - Returns: The element that was removed.
@_inlineable
public mutating func _customRemoveLast() -> Element? {
_precondition(count > 0, "Can't removeLast from an empty ${Self}")
@@ -1519,6 +1508,82 @@
self.replaceSubrange((i &- 1)..<i, with: EmptyCollection())
return result
}
+
+ /// Removes and returns the element at the specified position.
+ ///
+ /// All the elements following the specified position are moved up to
+ /// close the gap.
+ ///
+ /// var measurements: [Double] = [1.1, 1.5, 2.9, 1.2, 1.5, 1.3, 1.2]
+ /// let removed = measurements.remove(at: 2)
+ /// print(measurements)
+ /// // Prints "[1.1, 1.5, 1.2, 1.5, 1.3, 1.2]"
+ ///
+ /// - Parameter index: The position of the element to remove. `index` must
+ /// be a valid index of the array.
+ /// - Returns: The element at the specified index.
+ ///
+ /// - Complexity: O(*n*), where *n* is the length of the array.
+ @_inlineable
+ @discardableResult
+ public mutating func remove(at index: Int) -> Element {
+ let result = self[index]
+ self.replaceSubrange(index..<(index + 1), with: EmptyCollection())
+ return result
+ }
+
+%else:
+ /// Removes and returns the last element of the array.
+ ///
+ /// - Returns: The last element of the array if the array is not empty;
+ /// otherwise, `nil`.
+ ///
+ /// - Complexity: O(*n*) if the array is bridged, where *n* is the length
+ /// of the array; otherwise, O(1).
+ @_inlineable
+ public mutating func popLast() -> Element? {
+ guard !isEmpty else { return nil }
+ return _customRemoveLast().unsafelyUnwrapped
+ }
+
+ @_inlineable
+ public mutating func _customRemoveLast() -> Element? {
+ _precondition(!isEmpty, "Can't removeLast from an empty ${Self}")
+ _makeUniqueAndReserveCapacityIfNotUnique()
+ let newCount = _getCount() - 1
+ let pointer = (_buffer.firstElementAddress + newCount)
+ let element = pointer.move()
+ _buffer.count = newCount
+ return element
+ }
+ /// Removes and returns the element at the specified position.
+ ///
+ /// All the elements following the specified position are moved up to
+ /// close the gap.
+ ///
+ /// var measurements: [Double] = [1.1, 1.5, 2.9, 1.2, 1.5, 1.3, 1.2]
+ /// let removed = measurements.remove(at: 2)
+ /// print(measurements)
+ /// // Prints "[1.1, 1.5, 1.2, 1.5, 1.3, 1.2]"
+ ///
+ /// - Parameter index: The position of the element to remove. `index` must
+ /// be a valid index of the array.
+ /// - Returns: The element at the specified index.
+ ///
+ /// - Complexity: O(*n*), where *n* is the length of the array.
+ @_inlineable
+ @discardableResult
+ public mutating func remove(at index: Int) -> Element {
+ _precondition(index < endIndex, "Index out of range")
+ _precondition(index >= startIndex, "Index out of range")
+ _makeUniqueAndReserveCapacityIfNotUnique()
+ let newCount = _getCount() - 1
+ let pointer = (_buffer.firstElementAddress + index)
+ let result = pointer.move()
+ pointer.moveInitialize(from: pointer + 1, count: newCount - index)
+ _buffer.count = newCount
+ return result
+ }
%end
/// Inserts a new element at the specified position.
@@ -1546,29 +1611,6 @@
self.replaceSubrange(i..<i, with: CollectionOfOne(newElement))
}
- /// Removes and returns the element at the specified position.
- ///
- /// All the elements following the specified position are moved up to
- /// close the gap.
- ///
- /// var measurements: [Double] = [1.1, 1.5, 2.9, 1.2, 1.5, 1.3, 1.2]
- /// let removed = measurements.remove(at: 2)
- /// print(measurements)
- /// // Prints "[1.1, 1.5, 1.2, 1.5, 1.3, 1.2]"
- ///
- /// - Parameter index: The position of the element to remove. `index` must
- /// be a valid index of the array.
- /// - Returns: The element at the specified index.
- ///
- /// - Complexity: O(*n*), where *n* is the length of the array.
- @_inlineable
- @discardableResult
- public mutating func remove(at index: Int) -> Element {
- let result = self[index]
- self.replaceSubrange(index..<(index + 1), with: EmptyCollection())
- return result
- }
-
/// Removes all elements from the array.
///
/// - Parameter keepCapacity: Pass `true` to keep the existing capacity of
@@ -2358,35 +2400,6 @@
}
#endif
-extension Array {
- /// Removes and returns the last element of the array.
- ///
- /// - Returns: The last element of the array if the array is not empty;
- /// otherwise, `nil`.
- ///
- /// - Complexity: O(*n*) if the array is bridged, where *n* is the length
- /// of the array; otherwise, O(1).
- @_inlineable
- public mutating func popLast() -> Element? {
- guard !isEmpty else { return nil }
- return removeLast()
- }
-}
-
-extension ContiguousArray {
- /// Removes and returns the last element of the array.
- ///
- /// - Returns: The last element of the array if the array is not empty;
- /// otherwise, `nil`.
- ///
- /// - Complexity: O(1)
- @_inlineable
- public mutating func popLast() -> Element? {
- guard !isEmpty else { return nil }
- return removeLast()
- }
-}
-
extension ArraySlice {
@_inlineable
public // @testable
