Generic Structure

UnsafeMutableBufferPointer

A nonowning collection interface to a buffer of mutable elements stored contiguously in memory.

Declaration

struct UnsafeMutableBufferPointer<Element>

Overview

You can use an UnsafeMutableBufferPointer instance in low level operations to eliminate uniqueness checks and, in release mode, bounds checks. Bounds checks are always performed in debug mode.

UnsafeMutableBufferPointer Semantics

An UnsafeMutableBufferPointer instance is a view into memory and does not own the memory that it references. Copying a value of type UnsafeMutableBufferPointer does not copy the instances stored in the underlying memory. However, initializing another collection with an UnsafeMutableBufferPointer instance copies the instances out of the referenced memory and into the new collection.

Topics

Initializers

init(mutating: UnsafeBufferPointer<Element>)

Creates a mutable typed buffer pointer referencing the same memory as the given immutable buffer pointer.

init(rebasing: Slice<UnsafeMutableBufferPointer<Element>>)

Creates a buffer over the same memory as the given buffer slice.

init(start: UnsafeMutablePointer<Element>?, count: Int)

Creates a new buffer pointer over the specified number of contiguous instances beginning at the given pointer.

Instance Properties

var baseAddress: UnsafeMutablePointer<Element>?

A pointer to the first element of the buffer.

let count: Int

The number of elements in the buffer.

var count: Int

The number of elements in the collection.

var debugDescription: String

A textual representation of the buffer, suitable for debugging.

var endIndex: Int

The “past the end” position—that is, the position one greater than the last valid subscript argument.

var first: Element?

The first element of the collection.

var indices: Range<Int>

The indices that are valid for subscripting the collection, in ascending order.

var isEmpty: Bool

A Boolean value indicating whether the collection is empty.

var last: Element?

The last element of the collection.

var lazy: LazySequence<UnsafeMutableBufferPointer<Element>>

A sequence containing the same elements as this sequence, but on which some operations, such as map and filter, are implemented lazily.

var lazy: LazyCollection<UnsafeMutableBufferPointer<Element>>

A view onto this collection that provides lazy implementations of normally eager operations, such as map and filter.

var startIndex: Int

The index of the first element in a nonempty buffer.

var underestimatedCount: Int

A value less than or equal to the number of elements in the sequence, calculated nondestructively.

var underestimatedCount: Int

A value less than or equal to the number of elements in the collection.

Instance Methods

func allSatisfy((Element) -> Bool) -> Bool

Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.

func assign(repeating: UnsafeMutableBufferPointer<Element>.Element)

Assigns every element in this buffer’s memory to a copy of the given value.

func compactMap<ElementOfResult>((Element) -> ElementOfResult?) -> [ElementOfResult]

Returns an array containing the non-nil results of calling the given transformation with each element of this sequence.

func contains(Element) -> Bool

Returns a Boolean value indicating whether the sequence contains the given element.

func contains(where: (Element) -> Bool) -> Bool

Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.

func deallocate()

Deallocates the memory block previously allocated at this buffer pointer’s base address.

func drop(while: (Element) -> Bool) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence by skipping elements while predicate returns true and returning the remaining elements.

func dropFirst() -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence containing all but the first element of the sequence.

func dropFirst(Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence containing all but the given number of initial elements.

func dropLast() -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence containing all but the last element of the sequence.

func dropLast(Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence containing all but the specified number of final elements.

func elementsEqual<OtherSequence>(OtherSequence) -> Bool

Returns a Boolean value indicating whether this sequence and another sequence contain the same elements in the same order.

func elementsEqual<OtherSequence>(OtherSequence, by: (Element, OtherSequence.Element) -> Bool) -> Bool

Returns a Boolean value indicating whether this sequence and another sequence contain equivalent elements in the same order, using the given predicate as the equivalence test.

func enumerated() -> EnumeratedSequence<UnsafeMutableBufferPointer<Element>>

Returns a sequence of pairs (n, x), where n represents a consecutive integer starting at zero and x represents an element of the sequence.

func filter((Element) -> Bool) -> [Element]

Returns an array containing, in order, the elements of the sequence that satisfy the given predicate.

func first(where: (Element) -> Bool) -> Element?

Returns the first element of the sequence that satisfies the given predicate.

func firstIndex(of: Element) -> Int?

Returns the first index where the specified value appears in the collection.

func firstIndex(where: (Element) -> Bool) -> Int?

Returns the first index in which an element of the collection satisfies the given predicate.

func forEach((Element) -> Void)

Calls the given closure on each element in the sequence in the same order as a for-in loop.

func formIndex(inout Int, offsetBy: Int)

Offsets the given index by the specified distance.

func formIndex(inout Int, offsetBy: Int, limitedBy: Int) -> Bool

Offsets the given index by the specified distance, or so that it equals the given limiting index.

func initialize<S>(from: S) -> (S.Iterator, UnsafeMutableBufferPointer<Element>.Index)

Initializes the buffer’s memory with the given elements.

func initialize(repeating: UnsafeMutableBufferPointer<Element>.Element)

Initializes every element in this buffer’s memory to a copy of the given value.

func joined() -> FlattenSequence<UnsafeMutableBufferPointer<Element>>

Returns the elements of this sequence of sequences, concatenated.

func joined() -> FlattenCollection<UnsafeMutableBufferPointer<Element>>

Returns the elements of this collection of collections, concatenated.

func joined<Separator>(separator: Separator) -> JoinedSequence<UnsafeMutableBufferPointer<Element>>

Returns the concatenated elements of this sequence of sequences, inserting the given separator between each element.

func joined(separator: String) -> String

Returns a new string by concatenating the elements of the sequence, adding the given separator between each element.

func joined(separator: String) -> String

Returns a new string by concatenating the elements of the sequence, adding the given separator between each element.

func last(where: (Element) -> Bool) -> Element?

Returns the last element of the sequence that satisfies the given predicate.

func lastIndex(of: Element) -> Int?

Returns the last index where the specified value appears in the collection.

func lastIndex(where: (Element) -> Bool) -> Int?

Returns the index of the last element in the collection that matches the given predicate.

func lexicographicallyPrecedes<OtherSequence>(OtherSequence) -> Bool

Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the less-than operator (<) to compare elements.

func lexicographicallyPrecedes<OtherSequence>(OtherSequence, by: (Element, Element) -> Bool) -> Bool

Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the given predicate to compare elements.

func makeIterator() -> UnsafeMutableBufferPointer<Element>.Iterator

Returns an iterator over the elements of this buffer.

func map<T>((Element) -> T) -> [T]

Returns an array containing the results of mapping the given closure over the sequence’s elements.

func map<T>((Element) -> T) -> [T]

Returns an array containing the results of mapping the given closure over the sequence’s elements.

func max() -> Element?

Returns the maximum element in the sequence.

func max(by: (Element, Element) -> Bool) -> Element?

Returns the maximum element in the sequence, using the given predicate as the comparison between elements.

func min() -> Element?

Returns the minimum element in the sequence.

func min(by: (Element, Element) -> Bool) -> Element?

Returns the minimum element in the sequence, using the given predicate as the comparison between elements.

func partition(by: (Element) -> Bool) -> Int

Reorders the elements of the collection such that all the elements that match the given predicate are after all the elements that don’t match.

func partition(by: (Element) -> Bool) -> Int

Reorders the elements of the collection such that all the elements that match the given predicate are after all the elements that don’t match.

func prefix(Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence, up to the specified maximum length, containing the initial elements of the collection.

func prefix(through: Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence from the start of the collection through the specified position.

func prefix(upTo: Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence from the start of the collection up to, but not including, the specified position.

func prefix(while: (Element) -> Bool) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence containing the initial elements until predicate returns false and skipping the remaining elements.

func randomElement() -> Element?

Returns a random element of the collection.

func randomElement<T>(using: inout T) -> Element?

Returns a random element of the collection, using the given generator as a source for randomness.

func reduce<Result>(Result, (Result, Element) -> Result) -> Result

Returns the result of combining the elements of the sequence using the given closure.

func reduce<Result>(into: Result, (inout Result, Element) -> ()) -> Result

Returns the result of combining the elements of the sequence using the given closure.

func reverse()

Reverses the elements of the collection in place.

func reversed() -> ReversedCollection<UnsafeMutableBufferPointer<Element>>

Returns a view presenting the elements of the collection in reverse order.

func shuffle()

Shuffles the collection in place.

func shuffle<T>(using: inout T)

Shuffles the collection in place, using the given generator as a source for randomness.

func shuffled() -> [Element]

Returns the elements of the sequence, shuffled.

func shuffled<T>(using: inout T) -> [Element]

Returns the elements of the sequence, shuffled using the given generator as a source for randomness.

func sort()

Sorts the collection in place.

func sort(by: (Element, Element) -> Bool)

Sorts the collection in place, using the given predicate as the comparison between elements.

func sorted() -> [Element]

Returns the elements of the sequence, sorted.

func sorted(by: (Element, Element) -> Bool) -> [Element]

Returns the elements of the sequence, sorted using the given predicate as the comparison between elements.

func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (Element) -> Bool) -> [Slice<UnsafeMutableBufferPointer<Element>>]

Returns the longest possible subsequences of the collection, in order, that don’t contain elements satisfying the given predicate.

func split(separator: Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Slice<UnsafeMutableBufferPointer<Element>>]

Returns the longest possible subsequences of the sequence, in order, around elements equal to the given element.

func split(separator: Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Slice<UnsafeMutableBufferPointer<Element>>]

Returns the longest possible subsequences of the collection, in order, around elements equal to the given element.

func starts<PossiblePrefix>(with: PossiblePrefix) -> Bool

Returns a Boolean value indicating whether the initial elements of the sequence are the same as the elements in another sequence.

func starts<PossiblePrefix>(with: PossiblePrefix, by: (Element, PossiblePrefix.Element) -> Bool) -> Bool

Returns a Boolean value indicating whether the initial elements of the sequence are equivalent to the elements in another sequence, using the given predicate as the equivalence test.

func suffix(Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence, up to the given maximum length, containing the final elements of the collection.

func suffix(from: Int) -> Slice<UnsafeMutableBufferPointer<Element>>

Returns a subsequence from the specified position to the end of the collection.

func swapAt(Int, Int)

Exchanges the values at the specified indices of the buffer.

func withMemoryRebound<T, Result>(to: T.Type, (UnsafeMutableBufferPointer<T>) -> Result) -> Result

Executes the given closure while temporarily binding the memory referenced by this buffer to the given type.

Type Methods

static func allocate(capacity: Int) -> UnsafeMutableBufferPointer<UnsafeMutableBufferPointer<Element>.Element>

Allocates uninitialized memory for the specified number of instances of type Element.

See Also

Typed Pointers

struct UnsafePointer

A pointer for accessing data of a specific type.

struct UnsafeMutablePointer

A pointer for accessing and manipulating data of a specific type.

struct UnsafeBufferPointer

A nonowning collection interface to a buffer of elements stored contiguously in memory.