StructureSwift

UnsafeRawBufferPointer

A nonowning collection interface to the bytes in a region of memory.

@frozen struct UnsafeRawBufferPointer

Overview

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

An UnsafeRawBufferPointer instance is a view of the raw bytes in a region of memory. Each byte in memory is viewed as a UInt8 value independent of the type of values held in that memory. Reading from memory through a raw buffer is an untyped operation.

In addition to its collection interface, an UnsafeRawBufferPointer instance also supports the load(fromByteOffset:as:) and loadUnaligned(fromByteOffset:as:) methods provided by UnsafeRawPointer, including bounds checks in debug mode.

To access the underlying memory through typed operations, the memory must be bound to a trivial type.

UnsafeRawBufferPointer Semantics

An UnsafeRawBufferPointer instance is a view into memory and does not own the memory that it references. Copying a variable or constant of type UnsafeRawBufferPointer does not copy the underlying memory. However, initializing another collection with an UnsafeRawBufferPointer instance copies bytes out of the referenced memory and into the new collection.

The following example uses someBytes, an UnsafeRawBufferPointer instance, to demonstrate the difference between assigning a buffer pointer and using a buffer pointer as the source for another collection’s elements. Here, the assignment to destBytes creates a new, nonowning buffer pointer covering the first n bytes of the memory that someBytes references—nothing is copied:

var destBytes = someBytes[0..<n]

Next, the bytes referenced by destBytes are copied into byteArray, a new [UInt8] array, and then the remainder of someBytes is appended to byteArray:

var byteArray: [UInt8] = Array(destBytes)
byteArray += someBytes[n..<someBytes.count]

Members

Typealiases

typealias Element
A type representing the sequence’s elements.
typealias Index
A type that represents a position in the collection.
typealias Indices
A type that represents the indices that are valid for subscripting the collection, in ascending order.
typealias SubSequence
A collection representing a contiguous subrange of this collection’s elements. The subsequence shares indices with the original collection.

Initializers

init<T>(UnsafeBufferPointer<T>)
Creates a raw buffer over the contiguous bytes in the given typed buffer.
init(UnsafeMutableRawBufferPointer)
Creates a new buffer over the same memory as the given buffer.
init(UnsafeRawBufferPointer)
Creates a new buffer over the same memory as the given buffer.
init<T>(UnsafeMutableBufferPointer<T>)
Creates a raw buffer over the contiguous bytes in the given typed buffer.
init(rebasing: Slice<UnsafeMutableRawBufferPointer>)
Creates a raw buffer over the same memory as the given raw buffer slice, with the indices rebased to zero.
init(rebasing: Slice<UnsafeRawBufferPointer>)
Creates a raw buffer over the same memory as the given raw buffer slice, with the indices rebased to zero.
init(start: UnsafeRawPointer?, count: Int)
Creates a buffer over the specified number of contiguous bytes starting at the given pointer.

Instance Subscripts

subscript(Range<Self.Index>) -> Slice<Self>
Accesses a contiguous subrange of the collection’s elements.
subscript<R>(R) -> Self.SubSequence
Accesses the contiguous subrange of the collection’s elements specified by a range expression.
subscript((UnboundedRange_) -> ()) -> Self.SubSequence
subscript(Int) -> UnsafeRawBufferPointer.Element
Accesses the byte at the given offset in the memory region as a UInt8 value.
subscript(Range<Int>) -> UnsafeRawBufferPointer.SubSequence
Accesses the bytes in the specified memory region.

Instance Properties

var baseAddress: UnsafeRawPointer?
A pointer to the first byte of the buffer.
var count: Int
The number of elements in the collection.
var count: Int
The number of bytes in the buffer.
var debugDescription: String
A textual representation of the buffer, suitable for debugging.
var endIndex: UnsafeRawBufferPointer.Index
The “past the end” position—that is, the position one greater than the last valid subscript argument.
var first: Self.Element?
The first element of the collection.
var indices: UnsafeRawBufferPointer.Indices
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: Self.Element?
The last element of the collection.
var lazy: LazySequence<Self>
A sequence containing the same elements as this sequence, but on which some operations, such as map and filter, are implemented lazily.
var startIndex: UnsafeRawBufferPointer.Index
Always zero, which is the index of the first byte in a nonempty buffer.
var underestimatedCount: Int
A value less than or equal to the number of elements in the collection.
var underestimatedCount: Int
A value less than or equal to the number of elements in the sequence, calculated nondestructively.

Foundation

var regions: CollectionOfOne<UnsafeRawBufferPointer>
A BidirectionalCollection of DataProtocol elements which compose a discontiguous buffer of memory. Each region is a contiguous buffer of bytes.

Instance Methods

func allSatisfy((Self.Element) throws -> Bool) rethrows -> Bool
Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.
func assumingMemoryBound<T>(to: T.Type) -> UnsafeBufferPointer<T>
Returns a typed buffer to the memory referenced by this buffer, assuming that the memory is already bound to the specified type.
func bindMemory<T>(to: T.Type) -> UnsafeBufferPointer<T>
Binds this buffer’s memory to the specified type and returns a typed buffer of the bound memory.
func compactMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult]
Returns an array containing the non-nil results of calling the given transformation with each element of this sequence.
func contains(Self.Element) -> Bool
Returns a Boolean value indicating whether the sequence contains the given element.
func contains(where: (Self.Element) throws -> Bool) rethrows -> 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 difference<C>(from: C) -> CollectionDifference<Self.Element>
Returns the difference needed to produce this collection’s ordered elements from the given collection.
func difference<C>(from: C, by: (C.Element, Self.Element) -> Bool) -> CollectionDifference<Self.Element>
Returns the difference needed to produce this collection’s ordered elements from the given collection, using the given predicate as an equivalence test.
func drop(while: (Self.Element) throws -> Bool) rethrows -> Self.SubSequence
Returns a subsequence by skipping elements while predicate returns true and returning the remaining elements.
func dropFirst(Int) -> Self.SubSequence
Returns a subsequence containing all but the given number of initial elements.
func dropLast(Int) -> Self.SubSequence
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: (Self.Element, OtherSequence.Element) throws -> Bool) rethrows -> 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<Self>
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((Self.Element) throws -> Bool) rethrows -> [Self.Element]
Returns an array containing, in order, the elements of the sequence that satisfy the given predicate.
func first(where: (Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the first element of the sequence that satisfies the given predicate.
func firstIndex(of: Self.Element) -> Self.Index?
Returns the first index where the specified value appears in the collection.
func firstIndex(where: (Self.Element) throws -> Bool) rethrows -> Self.Index?
Returns the first index in which an element of the collection satisfies the given predicate.
func flatMap<SegmentOfResult>((Self.Element) throws -> SegmentOfResult) rethrows -> [SegmentOfResult.Element]
Returns an array containing the concatenated results of calling the given transformation with each element of this sequence.
func forEach((Self.Element) throws -> Void) rethrows
Calls the given closure on each element in the sequence in the same order as a for-in loop.
func formIndex(inout Self.Index, offsetBy: Int)
Offsets the given index by the specified distance.
func formIndex(inout Self.Index, offsetBy: Int, limitedBy: Self.Index) -> Bool
Offsets the given index by the specified distance, or so that it equals the given limiting index.
func formIndex(after: inout Self.Index)
Replaces the given index with its successor.
func formIndex(before: inout Self.Index)
Replaces the given index with its predecessor.
func index(Self.Index, offsetBy: Int, limitedBy: Self.Index) -> Self.Index?
Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.
func last(where: (Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the last element of the sequence that satisfies the given predicate.
func lastIndex(of: Self.Element) -> Self.Index?
Returns the last index where the specified value appears in the collection.
func lastIndex(where: (Self.Element) throws -> Bool) rethrows -> Self.Index?
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: (Self.Element, Self.Element) throws -> Bool) rethrows -> 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 load<T>(fromByteOffset: Int, as: T.Type) -> T
Returns a new instance of the given type, read from the buffer pointer’s raw memory at the specified byte offset.
func loadUnaligned<T>(fromByteOffset: Int, as: T.Type) -> T
Returns a new instance of the given type, constructed from the raw memory at the specified offset.
func makeIterator() -> UnsafeRawBufferPointer.Iterator
Returns an iterator over the bytes of this sequence.
func map<T>((Self.Element) throws -> T) rethrows -> [T]
Returns an array containing the results of mapping the given closure over the sequence’s elements.
func map<T>((Self.Element) throws -> T) rethrows -> [T]
Returns an array containing the results of mapping the given closure over the sequence’s elements.
func max() -> Self.Element?
Returns the maximum element in the sequence.
func max(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the maximum element in the sequence, using the given predicate as the comparison between elements.
func min() -> Self.Element?
Returns the minimum element in the sequence.
func min(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the minimum element in the sequence, using the given predicate as the comparison between elements.
func prefix(Int) -> Self.SubSequence
Returns a subsequence, up to the specified maximum length, containing the initial elements of the collection.
func prefix(through: Self.Index) -> Self.SubSequence
Returns a subsequence from the start of the collection through the specified position.
func prefix(upTo: Self.Index) -> Self.SubSequence
Returns a subsequence from the start of the collection up to, but not including, the specified position.
func prefix(while: (Self.Element) throws -> Bool) rethrows -> Self.SubSequence
Returns a subsequence containing the initial elements until predicate returns false and skipping the remaining elements.
func randomElement() -> Self.Element?
Returns a random element of the collection.
func randomElement<T>(using: inout T) -> Self.Element?
Returns a random element of the collection, using the given generator as a source for randomness.
func reduce<Result>(Result, (Result, Self.Element) throws -> Result) rethrows -> Result
Returns the result of combining the elements of the sequence using the given closure.
func reduce<Result>(into: Result, (inout Result, Self.Element) throws -> ()) rethrows -> Result
Returns the result of combining the elements of the sequence using the given closure.
func reversed() -> ReversedCollection<Self>
Returns a view presenting the elements of the collection in reverse order.
func shuffled() -> [Self.Element]
Returns the elements of the sequence, shuffled.
func shuffled<T>(using: inout T) -> [Self.Element]
Returns the elements of the sequence, shuffled using the given generator as a source for randomness.
func sorted() -> [Self.Element]
Returns the elements of the sequence, sorted.
func sorted(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> [Self.Element]
Returns the elements of the sequence, sorted using the given predicate as the comparison between elements.
func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (Self.Element) throws -> Bool) rethrows -> [Self.SubSequence]
Returns the longest possible subsequences of the collection, in order, that don’t contain elements satisfying the given predicate.
func split(separator: Self.Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Self.SubSequence]
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: (Self.Element, PossiblePrefix.Element) throws -> Bool) rethrows -> 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) -> Self.SubSequence
Returns a subsequence, up to the given maximum length, containing the final elements of the collection.
func suffix(from: Self.Index) -> Self.SubSequence
Returns a subsequence from the specified position to the end of the collection.
func withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R?
Executes a closure on the sequence’s contiguous storage.
func withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<UnsafeRawBufferPointer.Element>) throws -> R) rethrows -> R?
Executes a closure on the sequence’s contiguous storage.
func withMemoryRebound<T, Result>(to: T.Type, (UnsafeBufferPointer<T>) throws -> Result) rethrows -> Result
Executes the given closure while temporarily binding the buffer to instances of type T.

Foundation

func copyBytes(to: UnsafeMutableRawBufferPointer) -> Int
func copyBytes(to: UnsafeMutableRawBufferPointer, count: Int) -> Int
func copyBytes<R>(to: UnsafeMutableRawBufferPointer, from: R) -> Int
func copyBytes<DestinationType, R>(to: UnsafeMutableBufferPointer<DestinationType>, from: R)
func copyBytes<DestinationType, R>(to: UnsafeMutableBufferPointer<DestinationType>, from: R) -> Int
func firstRange<D>(of: D) -> Range<Self.Index>?
func firstRange<D, R>(of: D, in: R) -> Range<Self.Index>?
Returns the first found range of the given data buffer.
func lastRange<D>(of: D) -> Range<Self.Index>?
func lastRange<D, R>(of: D, in: R) -> Range<Self.Index>?
Returns the last found range of the given data buffer.
func withUnsafeBytes<R>((UnsafeRawBufferPointer) throws -> R) rethrows -> R
Calls the given closure with the contents of underlying storage.

Structures

struct Iterator
An iterator over the bytes viewed by a raw buffer pointer.

Removed Members

Instance Methods

func flatMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult]
func index(of: Self.Element) -> Self.Index?
Returns the first index where the specified value appears in the collection.

UnsafeRawBufferPointer

Overview

UnsafeRawBufferPointer Semantics

Members

Typealiases

Initializers

Instance Subscripts

Instance Properties

Foundation

Instance Methods

Foundation

Structures

Conforms To

Foundation

Removed Members

Instance Methods