Structure

DispatchData

An object that manages a memory-based data buffer and exposes it as a contiguous block of memory.

Declaration

struct DispatchData

Overview

The memory buffer managed by this object may be a single contiguous block of memory, or it may consist of multiple discontiguous blocks. For the discontiguous case, the dispatch data object makes it appear as if the memory is contiguous.

Topics

Creating a Dispatch Data Structure

init(bytes: UnsafeRawBufferPointer)

Creates a new dispatch data object from the specified memory buffer.

init(bytesNoCopy: UnsafeRawBufferPointer, deallocator: DispatchData.Deallocator)

Creates a new dispatch data object using the specified memory buffer and deallocator.

enum DispatchData.Deallocator

Memory deallocators for dispatch data objects.

static let empty: DispatchData

A dispatch data object representing a zero-length memory region.

Accessing Buffer Data

subscript<R>(R) -> Slice<DispatchData>

Accesses the contiguous subrange of the collection’s elements specified by a range expression.

func randomElement() -> UInt8?

Returns a random element of the collection.

func randomElement<T>(using: inout T) -> UInt8?

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

var lazy: LazySequence<DispatchData>

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

Getting Information About the Buffer

var isEmpty: Bool

A Boolean value indicating whether the collection is empty.

var first: UInt8?

The first element of the collection.

var last: UInt8?

The last element of the collection.

var underestimatedCount: Int

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

func max() -> UInt8?

Returns the maximum element in the sequence.

func max(by: (UInt8, UInt8) -> Bool) -> UInt8?

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

func min() -> UInt8?

Returns the minimum element in the sequence.

func min(by: (UInt8, UInt8) -> Bool) -> UInt8?

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

func distance(from: Int, to: Int) -> Int

Returns the distance between two indexes.

func allSatisfy((UInt8) -> Bool) -> Bool

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

Getting Buffer Indexes

func firstIndex(of: UInt8) -> Int?

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

func firstIndex(where: (UInt8) -> Bool) -> Int?

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

func lastIndex(of: UInt8) -> Int?

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

func lastIndex(where: (UInt8) -> Bool) -> Int?

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

func index(Int, offsetBy: Int) -> Int

Returns an index that is the specified distance from the given index.

func index(Int, offsetBy: Int, limitedBy: Int) -> Int?

Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.

var indices: DefaultIndices<DispatchData>

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

Offsetting Index Values

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 formIndex(after: inout Int)

Replaces the given index with its successor.

func formIndex(before: inout Int)

Replaces the given index with its predecessor.

Filtering the Buffer with a Predicate

func first(where: (UInt8) -> Bool) -> UInt8?

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

func last(where: (UInt8) -> Bool) -> UInt8?

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

func filter((UInt8) -> Bool) -> [UInt8]

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

Iterating Over the Buffer Contents

func forEach((UInt8) -> Void)

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

func enumerated() -> EnumeratedSequence<DispatchData>

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

typealias DispatchData.Iterator

A type that provides the collection's iteration interface and encapsulates its iteration state.

Retrieving Buffer Subsequences

func drop(while: (UInt8) -> Bool) -> Slice<DispatchData>

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

func dropFirst(Int) -> Slice<DispatchData>

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

func dropLast(Int) -> Slice<DispatchData>

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

func prefix(Int) -> Slice<DispatchData>

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

func prefix(through: Int) -> Slice<DispatchData>

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

func prefix(upTo: Int) -> Slice<DispatchData>

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

func prefix(while: (UInt8) -> Bool) -> Slice<DispatchData>

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

func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (UInt8) -> Bool) -> [Slice<DispatchData>]

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

func split(separator: UInt8, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Slice<DispatchData>]

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

func suffix(Int) -> Slice<DispatchData>

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

func suffix(from: Int) -> Slice<DispatchData>

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

Comparing Buffer Data

func contains(UInt8) -> Bool

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

func contains(where: (UInt8) -> Bool) -> Bool

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

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: (UInt8, 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 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: (UInt8, UInt8) -> 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 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: (UInt8, 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.

Mapping Buffer Elements

func compactMap<ElementOfResult>((UInt8) -> ElementOfResult?) -> [ElementOfResult]

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

func map<T>((UInt8) -> T) -> [T]

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

Sorting Buffer Elements

func sorted() -> [UInt8]

Returns the elements of the sequence, sorted.

func sorted(by: (UInt8, UInt8) -> Bool) -> [UInt8]

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

func shuffled() -> [UInt8]

Returns the elements of the sequence, shuffled.

func shuffled<T>(using: inout T) -> [UInt8]

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

func reversed() -> ReversedCollection<DispatchData>

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

Combining Sequence Elements

func allSatisfy((UInt8) -> Bool) -> Bool

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

func compactMap<ElementOfResult>((UInt8) -> ElementOfResult?) -> [ElementOfResult]

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

func contains(UInt8) -> Bool

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

func contains(where: (UInt8) -> Bool) -> Bool

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

func distance(from: Int, to: Int) -> Int

Returns the distance between two indexes.

func drop(while: (UInt8) -> Bool) -> Slice<DispatchData>

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

func dropFirst(Int) -> Slice<DispatchData>

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

func dropLast(Int) -> Slice<DispatchData>

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: (UInt8, 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<DispatchData>

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((UInt8) -> Bool) -> [UInt8]

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

func first(where: (UInt8) -> Bool) -> UInt8?

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

func firstIndex(of: UInt8) -> Int?

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

func firstIndex(where: (UInt8) -> Bool) -> Int?

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

func forEach((UInt8) -> 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 formIndex(after: inout Int)

Replaces the given index with its successor.

func formIndex(before: inout Int)

Replaces the given index with its predecessor.

func index(Int, offsetBy: Int) -> Int

Returns an index that is the specified distance from the given index.

func index(Int, offsetBy: Int, limitedBy: Int) -> Int?

Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.

func last(where: (UInt8) -> Bool) -> UInt8?

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

func lastIndex(of: UInt8) -> Int?

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

func lastIndex(where: (UInt8) -> 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: (UInt8, UInt8) -> 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 map<T>((UInt8) -> T) -> [T]

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

func max() -> UInt8?

Returns the maximum element in the sequence.

func max(by: (UInt8, UInt8) -> Bool) -> UInt8?

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

func min() -> UInt8?

Returns the minimum element in the sequence.

func min(by: (UInt8, UInt8) -> Bool) -> UInt8?

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

func prefix(Int) -> Slice<DispatchData>

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

func prefix(through: Int) -> Slice<DispatchData>

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

func prefix(upTo: Int) -> Slice<DispatchData>

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

func prefix(while: (UInt8) -> Bool) -> Slice<DispatchData>

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

func randomElement() -> UInt8?

Returns a random element of the collection.

func randomElement<T>(using: inout T) -> UInt8?

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

func reduce<Result>(Result, (Result, UInt8) -> Result) -> Result

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

func reversed() -> ReversedCollection<DispatchData>

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

func shuffled() -> [UInt8]

Returns the elements of the sequence, shuffled.

func shuffled<T>(using: inout T) -> [UInt8]

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

func sorted() -> [UInt8]

Returns the elements of the sequence, sorted.

func sorted(by: (UInt8, UInt8) -> Bool) -> [UInt8]

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

func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (UInt8) -> Bool) -> [Slice<DispatchData>]

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

func split(separator: UInt8, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Slice<DispatchData>]

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: (UInt8, 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<DispatchData>

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

func suffix(from: Int) -> Slice<DispatchData>

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

Instance Methods

func difference<C>(from: C) -> CollectionDifference<UInt8>

Returns the difference needed to produce this collection’s ordered elements from the given collection.

func difference<C>(from: C, by: (C.Element, UInt8) -> Bool) -> CollectionDifference<UInt8>

Returns the difference needed to produce this collection’s ordered elements from the given collection, using the given predicate as an equivalence test.

func flatMap<SegmentOfResult>((UInt8) -> SegmentOfResult) -> [SegmentOfResult.Element]

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

func index(of: UInt8) -> Int?

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

Deprecated
func index(where: (UInt8) -> Bool) -> Int?

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

Deprecated
func reduce<Result>(into: Result, (inout Result, UInt8) -> ()) -> Result

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

func withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<UInt8>) -> R) -> R?

Call body(p), where p is a pointer to the collection’s contiguous storage. If no such storage exists, it is first created. If the collection does not support an internal representation in a form of contiguous storage, body is not called and nil is returned.

Relationships

See Also

System Event Monitoring

class DispatchSource

An object that coordinates the processing of specific low-level system events, such as file-system events, timers, and UNIX signals.

class DispatchIO

An object that manages operations on a file descriptor using either stream-based or random-access semantics.

struct DispatchDataIterator

A byte-by-byte iterator over the contents of a dispatch data object.