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//===--- UnsafePointer.swift ----------------------------------*- swift -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
/// A pointer for accessing data of a specific type.
///
/// You use instances of the `UnsafePointer` type to access data of a
/// specific type in memory. The type of data that a pointer can access is the
/// pointer's `Pointee` type. `UnsafePointer` provides no automated
/// memory management or alignment guarantees. You are responsible for
/// handling the life cycle of any memory you work with through unsafe
/// pointers to avoid leaks or undefined behavior.
///
/// Memory that you manually manage can be either *untyped* or *bound* to a
/// specific type. You use the `UnsafePointer` type to access and
/// manage memory that has been bound to a specific type.
///
/// Understanding a Pointer's Memory State
/// ======================================
///
/// The memory referenced by an `UnsafePointer` instance can be in
/// one of several states. Many pointer operations must only be applied to
/// pointers with memory in a specific state---you must keep track of the
/// state of the memory you are working with and understand the changes to
/// that state that different operations perform. Memory can be untyped and
/// uninitialized, bound to a type and uninitialized, or bound to a type and
/// initialized to a value. Finally, memory that was allocated previously may
/// have been deallocated, leaving existing pointers referencing unallocated
/// memory.
///
/// Uninitialized Memory
/// --------------------
///
/// Memory that has just been allocated through a typed pointer or has been
/// deinitialized is in an *uninitialized* state. Uninitialized memory must be
/// initialized before it can be accessed for reading.
///
/// Initialized Memory
/// ------------------
///
/// *Initialized* memory has a value that can be read using a pointer's
/// `pointee` property or through subscript notation. In the following
/// example, `ptr` is a pointer to memory initialized with a value of `23`:
///
/// let ptr: UnsafePointer<Int> = ...
/// // ptr.pointee == 23
/// // ptr[0] == 23
///
/// Accessing a Pointer's Memory as a Different Type
/// ================================================
///
/// When you access memory through an `UnsafePointer` instance, the
/// `Pointee` type must be consistent with the bound type of the memory. If
/// you do need to access memory that is bound to one type as a different
/// type, Swift's pointer types provide type-safe ways to temporarily or
/// permanently change the bound type of the memory, or to load typed
/// instances directly from raw memory.
///
/// An `UnsafePointer<UInt8>` instance allocated with eight bytes of
/// memory, `uint8Pointer`, will be used for the examples below.
///
/// let uint8Pointer: UnsafePointer<UInt8> = fetchEightBytes()
///
/// When you only need to temporarily access a pointer's memory as a different
/// type, use the `withMemoryRebound(to:capacity:)` method. For example, you
/// can use this method to call an API that expects a pointer to a different
/// type that is layout compatible with your pointer's `Pointee`. The following
/// code temporarily rebinds the memory that `uint8Pointer` references from
/// `UInt8` to `Int8` to call the imported C `strlen` function.
///
/// // Imported from C
/// func strlen(_ __s: UnsafePointer<Int8>!) -> UInt
///
/// let length = uint8Pointer.withMemoryRebound(to: Int8.self, capacity: 8) {
/// return strlen($0)
/// }
/// // length == 7
///
/// When you need to permanently rebind memory to a different type, first
/// obtain a raw pointer to the memory and then call the
/// `bindMemory(to:capacity:)` method on the raw pointer. The following
/// example binds the memory referenced by `uint8Pointer` to one instance of
/// the `UInt64` type:
///
/// let uint64Pointer = UnsafeRawPointer(uint8Pointer)
/// .bindMemory(to: UInt64.self, capacity: 1)
///
/// After rebinding the memory referenced by `uint8Pointer` to `UInt64`,
/// accessing that pointer's referenced memory as a `UInt8` instance is
/// undefined.
///
/// var fullInteger = uint64Pointer.pointee // OK
/// var firstByte = uint8Pointer.pointee // undefined
///
/// Alternatively, you can access the same memory as a different type without
/// rebinding through untyped memory access, so long as the bound type and the
/// destination type are trivial types. Convert your pointer to an
/// `UnsafeRawPointer` instance and then use the raw pointer's
/// `load(fromByteOffset:as:)` method to read values.
///
/// let rawPointer = UnsafeRawPointer(uint64Pointer)
/// let fullInteger = rawPointer.load(as: UInt64.self) // OK
/// let firstByte = rawPointer.load(as: UInt8.self) // OK
///
/// Performing Typed Pointer Arithmetic
/// ===================================
///
/// Pointer arithmetic with a typed pointer is counted in strides of the
/// pointer's `Pointee` type. When you add to or subtract from an `UnsafePointer`
/// instance, the result is a new pointer of the same type, offset by that
/// number of instances of the `Pointee` type.
///
/// // 'intPointer' points to memory initialized with [10, 20, 30, 40]
/// let intPointer: UnsafePointer<Int> = ...
///
/// // Load the first value in memory
/// let x = intPointer.pointee
/// // x == 10
///
/// // Load the third value in memory
/// let offsetPointer = intPointer + 2
/// let y = offsetPointer.pointee
/// // y == 30
///
/// You can also use subscript notation to access the value in memory at a
/// specific offset.
///
/// let z = intPointer[2]
/// // z == 30
///
/// Implicit Casting and Bridging
/// =============================
///
/// When calling a function or method with an `UnsafePointer` parameter, you can pass
/// an instance of that specific pointer type, pass an instance of a
/// compatible pointer type, or use Swift's implicit bridging to pass a
/// compatible pointer.
///
/// For example, the `printInt(atAddress:)` function in the following code
/// sample expects an `UnsafePointer<Int>` instance as its first parameter:
///
/// func printInt(atAddress p: UnsafePointer<Int>) {
/// print(p.pointee)
/// }
///
/// As is typical in Swift, you can call the `printInt(atAddress:)` function
/// with an `UnsafePointer` instance. This example passes `intPointer`, a pointer to
/// an `Int` value, to `print(address:)`.
///
/// printInt(atAddress: intPointer)
/// // Prints "42"
///
/// Because a mutable typed pointer can be implicitly cast to an immutable
/// pointer with the same `Pointee` type when passed as a parameter, you can
/// also call `printInt(atAddress:)` with an `UnsafeMutablePointer` instance.
///
/// let mutableIntPointer = UnsafeMutablePointer(mutating: intPointer)
/// printInt(atAddress: mutableIntPointer)
/// // Prints "42"
///
/// Alternatively, you can use Swift's *implicit bridging* to pass a pointer to
/// an instance or to the elements of an array. The following example passes a
/// pointer to the `value` variable by using inout syntax:
///
/// var value: Int = 23
/// printInt(atAddress: &value)
/// // Prints "23"
///
/// An immutable pointer to the elements of an array is implicitly created when
/// you pass the array as an argument. This example uses implicit bridging to
/// pass a pointer to the elements of `numbers` when calling
/// `printInt(atAddress:)`.
///
/// let numbers = [5, 10, 15, 20]
/// printInt(atAddress: numbers)
/// // Prints "5"
///
/// You can also use inout syntax to pass a mutable pointer to the elements of
/// an array. Because `printInt(atAddress:)` requires an immutable pointer,
/// although this is syntactically valid, it isn't necessary.
///
/// var mutableNumbers = numbers
/// printInt(atAddress: &mutableNumbers)
///
/// No matter which way you call `printInt(atAddress:)`, Swift's type safety
/// guarantees that you can only pass a pointer to the type required by the
/// function---in this case, a pointer to an `Int`.
///
/// - Important: The pointer created through implicit bridging of an instance
/// or of an array's elements is only valid during the execution of the
/// called function. Escaping the pointer to use after the execution of the
/// function is undefined behavior. In particular, do not use implicit
/// bridging when calling an `UnsafePointer` initializer.
///
/// var number = 5
/// let numberPointer = UnsafePointer<Int>(&number)
/// // Accessing 'numberPointer' is undefined behavior.
@frozen // unsafe-performance
public struct UnsafePointer<Pointee: ~Copyable>: Copyable {
/// The underlying raw (untyped) pointer.
@_preInverseGenerics
public let _rawValue: Builtin.RawPointer
/// Creates an `UnsafePointer` from a builtin raw pointer.
@_transparent
@_preInverseGenerics
public init(_ _rawValue: Builtin.RawPointer) {
self._rawValue = _rawValue
}
}
@available(*, unavailable)
extension UnsafePointer: Sendable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafePointer: _Pointer where Pointee: ~Copyable {
/// A type that represents the distance between two pointers.
public typealias Distance = Int
}
@_preInverseGenerics
extension UnsafePointer: Equatable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafePointer: Hashable where Pointee: ~Copyable {
// Note: This explicit `hashValue` applies @_preInverseGenerics to emulate the
// original (pre-6.0) compiler-synthesized version.
@_preInverseGenerics
public var hashValue: Int {
_hashValue(for: self)
}
}
@_preInverseGenerics
extension UnsafePointer: Comparable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafePointer: Strideable where Pointee: ~Copyable {}
#if !$Embedded
@_preInverseGenerics
extension UnsafePointer: CustomDebugStringConvertible
where Pointee: ~Copyable {}
#endif
#if SWIFT_ENABLE_REFLECTION
@_preInverseGenerics
extension UnsafePointer: CustomReflectable where Pointee: ~Copyable {}
#endif
extension UnsafePointer where Pointee: ~Copyable {
/// Deallocates the memory block previously allocated at this pointer.
///
/// This pointer must be a pointer to the start of a previously allocated
/// memory block. The memory must not be initialized or `Pointee` must be a
/// trivial type.
@inlinable
@_preInverseGenerics
public func deallocate() {
// Passing zero alignment to the runtime forces "aligned
// deallocation". Since allocation via `UnsafeMutable[Raw][Buffer]Pointer`
// always uses the "aligned allocation" path, this ensures that the
// runtime's allocation and deallocation paths are compatible.
Builtin.deallocRaw(_rawValue, (-1)._builtinWordValue, (0)._builtinWordValue)
}
}
extension UnsafePointer where Pointee: ~Copyable {
/// Accesses the instance referenced by this pointer.
///
/// When reading from the `pointee` property, the instance referenced by
/// this pointer must already be initialized.
@_alwaysEmitIntoClient
public var pointee: Pointee {
@_transparent unsafeAddress {
return self
}
}
}
@_disallowFeatureSuppression(NoncopyableGenerics)
extension UnsafePointer {
// This preserves the ABI of the original (pre-6.0) `pointee` property that
// used to export a getter. The current one above would export a read
// accessor, if it wasn't @_alwaysEmitIntoClient.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@usableFromInline
internal var pointee: Pointee {
@_transparent unsafeAddress {
return self
}
}
}
extension UnsafePointer where Pointee: ~Copyable {
/// Accesses the pointee at the specified offset from this pointer.
///
/// For a pointer `p`, the memory at `p + i` must be initialized.
///
/// - Parameter i: The offset from this pointer at which to access an
/// instance, measured in strides of the pointer's `Pointee` type.
@_alwaysEmitIntoClient
public subscript(i: Int) -> Pointee {
@_transparent
unsafeAddress {
return self + i
}
}
}
@_disallowFeatureSuppression(NoncopyableGenerics)
extension UnsafePointer {
// This preserves the ABI of the original (pre-6.0) subscript that used to
// export a getter. The current one above would export a read accessor, if it
// wasn't @_alwaysEmitIntoClient.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@usableFromInline
internal subscript(i: Int) -> Pointee {
@_transparent
unsafeAddress {
return self + i
}
}
}
extension UnsafePointer where Pointee: ~Copyable {
/// Executes the given closure while temporarily binding memory to
/// the specified number of instances of type `T`.
///
/// Use this method when you have a pointer to memory bound to one type and
/// you need to access that memory as instances of another type. Accessing
/// memory as a type `T` requires that the memory be bound to that type. A
/// memory location may only be bound to one type at a time, so accessing
/// the same memory as an unrelated type without first rebinding the memory
/// is undefined.
///
/// The region of memory that starts at this pointer and covers `count`
/// strides of `T` instances must be bound to `Pointee`.
/// Any instance of `T` within the re-bound region may be initialized or
/// uninitialized. Every instance of `Pointee` overlapping with a given
/// instance of `T` should have the same initialization state (i.e.
/// initialized or uninitialized.) Accessing a `T` whose underlying
/// `Pointee` storage is in a mixed initialization state shall be
/// undefined behaviour.
///
/// The following example temporarily rebinds the memory of a `UInt64`
/// pointer to `Int64`, then accesses a property on the signed integer.
///
/// let uint64Pointer: UnsafePointer<UInt64> = fetchValue()
/// let isNegative = uint64Pointer.withMemoryRebound(
/// to: Int64.self, capacity: 1
/// ) {
/// return $0.pointee < 0
/// }
///
/// Because this pointer's memory is no longer bound to its `Pointee` type
/// while the `body` closure executes, do not access memory using the
/// original pointer from within `body`. Instead, use the `body` closure's
/// pointer argument to access the values in memory as instances of type
/// `T`.
///
/// After executing `body`, this method rebinds memory back to the original
/// `Pointee` type.
///
/// - Note: Only use this method to rebind the pointer's memory to a type
/// that is layout compatible with the `Pointee` type. The stride of the
/// temporary type (`T`) may be an integer multiple or a whole fraction
/// of `Pointee`'s stride, for example to point to one element of
/// an aggregate.
/// To bind a region of memory to a type that does not match these
/// requirements, convert the pointer to a raw pointer and use the
/// `bindMemory(to:)` method.
/// If `T` and `Pointee` have different alignments, this pointer
/// must be aligned with the larger of the two alignments.
///
/// - Parameters:
/// - type: The type to temporarily bind the memory referenced by this
/// pointer. The type `T` must be layout compatible
/// with the pointer's `Pointee` type.
/// - count: The number of instances of `T` in the re-bound region.
/// - body: A closure that takes a typed pointer to the
/// same memory as this pointer, only bound to type `T`. The closure's
/// pointer argument is valid only for the duration of the closure's
/// execution. If `body` has a return value, that value is also used as
/// the return value for the `withMemoryRebound(to:capacity:_:)` method.
/// - pointer: The pointer temporarily bound to `T`.
/// - Returns: The return value, if any, of the `body` closure parameter.
@_alwaysEmitIntoClient
public func withMemoryRebound<T: ~Copyable, E: Error, Result: ~Copyable>(
to type: T.Type,
capacity count: Int,
_ body: (_ pointer: UnsafePointer<T>) throws(E) -> Result
) throws(E) -> Result {
_debugPrecondition(
Int(bitPattern: .init(_rawValue)) & (MemoryLayout<T>.alignment-1) == 0 &&
( count == 1 ||
( MemoryLayout<Pointee>.stride > MemoryLayout<T>.stride
? MemoryLayout<Pointee>.stride % MemoryLayout<T>.stride == 0
: MemoryLayout<T>.stride % MemoryLayout<Pointee>.stride == 0
)
),
"self must be a properly aligned pointer for types Pointee and T"
)
let binding = Builtin.bindMemory(_rawValue, count._builtinWordValue, T.self)
defer { Builtin.rebindMemory(_rawValue, binding) }
return try body(.init(_rawValue))
}
}
extension UnsafePointer {
// This unavailable implementation uses the expected mangled name
// of `withMemoryRebound<T, Result>(to:capacity:_:)`, and provides
// an entry point for any binary linked against the stdlib binary
// for Swift 5.6 and older.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@_silgen_name("$sSP17withMemoryRebound2to8capacity_qd_0_qd__m_Siqd_0_SPyqd__GKXEtKr0_lF")
@usableFromInline
internal func _legacy_se0333_withMemoryRebound<T, Result>(
to type: T.Type,
capacity count: Int,
_ body: (UnsafePointer<T>) throws -> Result
) rethrows -> Result {
let binding = Builtin.bindMemory(_rawValue, count._builtinWordValue, T.self)
defer { Builtin.rebindMemory(_rawValue, binding) }
return try body(.init(_rawValue))
}
}
extension UnsafePointer {
/// Obtain a pointer to the stored property referred to by a key path.
///
/// If the key path represents a computed property,
/// this function will return `nil`.
///
/// - Parameter property: A `KeyPath` whose `Root` is `Pointee`.
/// - Returns: A pointer to the stored property represented
/// by the key path, or `nil`.
@_alwaysEmitIntoClient
#if $Embedded
@_transparent
#endif
public func pointer<Property>(
to property: KeyPath<Pointee, Property>
) -> UnsafePointer<Property>? {
guard let o = property._storedInlineOffset else { return nil }
_internalInvariant(o >= 0)
_debugPrecondition(
o == 0 || UnsafeRawPointer(self) < UnsafeRawPointer(bitPattern: 0 &- o)!,
"Overflow in pointer arithmetic"
)
return .init(Builtin.gepRaw_Word(_rawValue, o._builtinWordValue))
}
}
extension UnsafePointer where Pointee: ~Copyable {
@inlinable // unsafe-performance
@_preInverseGenerics
internal static var _max: UnsafePointer {
return UnsafePointer(
bitPattern: 0 as Int &- MemoryLayout<Pointee>.stride
)._unsafelyUnwrappedUnchecked
}
}
/// A pointer for accessing and manipulating data of a
/// specific type.
///
/// You use instances of the `UnsafeMutablePointer` type to access data of a
/// specific type in memory. The type of data that a pointer can access is the
/// pointer's `Pointee` type. `UnsafeMutablePointer` provides no automated
/// memory management or alignment guarantees. You are responsible for
/// handling the life cycle of any memory you work with through unsafe
/// pointers to avoid leaks or undefined behavior.
///
/// Memory that you manually manage can be either *untyped* or *bound* to a
/// specific type. You use the `UnsafeMutablePointer` type to access and
/// manage memory that has been bound to a specific type.
///
/// Understanding a Pointer's Memory State
/// ======================================
///
/// The memory referenced by an `UnsafeMutablePointer` instance can be in
/// one of several states. Many pointer operations must only be applied to
/// pointers with memory in a specific state---you must keep track of the
/// state of the memory you are working with and understand the changes to
/// that state that different operations perform. Memory can be untyped and
/// uninitialized, bound to a type and uninitialized, or bound to a type and
/// initialized to a value. Finally, memory that was allocated previously may
/// have been deallocated, leaving existing pointers referencing unallocated
/// memory.
///
/// Uninitialized Memory
/// --------------------
///
/// Memory that has just been allocated through a typed pointer or has been
/// deinitialized is in an *uninitialized* state. Uninitialized memory must be
/// initialized before it can be accessed for reading.
///
/// You can use methods like `initialize(repeating:count:)`, `initialize(from:count:)`,
/// and `moveInitialize(from:count:)` to initialize the memory referenced by a
/// pointer with a value or series of values.
///
/// Initialized Memory
/// ------------------
///
/// *Initialized* memory has a value that can be read using a pointer's
/// `pointee` property or through subscript notation. In the following
/// example, `ptr` is a pointer to memory initialized with a value of `23`:
///
/// let ptr: UnsafeMutablePointer<Int> = ...
/// // ptr.pointee == 23
/// // ptr[0] == 23
///
/// Accessing a Pointer's Memory as a Different Type
/// ================================================
///
/// When you access memory through an `UnsafeMutablePointer` instance, the
/// `Pointee` type must be consistent with the bound type of the memory. If
/// you do need to access memory that is bound to one type as a different
/// type, Swift's pointer types provide type-safe ways to temporarily or
/// permanently change the bound type of the memory, or to load typed
/// instances directly from raw memory.
///
/// An `UnsafeMutablePointer<UInt8>` instance allocated with eight bytes of
/// memory, `uint8Pointer`, will be used for the examples below.
///
/// var bytes: [UInt8] = [39, 77, 111, 111, 102, 33, 39, 0]
/// let uint8Pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 8)
/// uint8Pointer.initialize(from: &bytes, count: 8)
///
/// When you only need to temporarily access a pointer's memory as a different
/// type, use the `withMemoryRebound(to:capacity:)` method. For example, you
/// can use this method to call an API that expects a pointer to a different
/// type that is layout compatible with your pointer's `Pointee`. The following
/// code temporarily rebinds the memory that `uint8Pointer` references from
/// `UInt8` to `Int8` to call the imported C `strlen` function.
///
/// // Imported from C
/// func strlen(_ __s: UnsafePointer<Int8>!) -> UInt
///
/// let length = uint8Pointer.withMemoryRebound(to: Int8.self, capacity: 8) {
/// return strlen($0)
/// }
/// // length == 7
///
/// When you need to permanently rebind memory to a different type, first
/// obtain a raw pointer to the memory and then call the
/// `bindMemory(to:capacity:)` method on the raw pointer. The following
/// example binds the memory referenced by `uint8Pointer` to one instance of
/// the `UInt64` type:
///
/// let uint64Pointer = UnsafeMutableRawPointer(uint8Pointer)
/// .bindMemory(to: UInt64.self, capacity: 1)
///
/// After rebinding the memory referenced by `uint8Pointer` to `UInt64`,
/// accessing that pointer's referenced memory as a `UInt8` instance is
/// undefined.
///
/// var fullInteger = uint64Pointer.pointee // OK
/// var firstByte = uint8Pointer.pointee // undefined
///
/// Alternatively, you can access the same memory as a different type without
/// rebinding through untyped memory access, so long as the bound type and the
/// destination type are trivial types. Convert your pointer to an
/// `UnsafeMutableRawPointer` instance and then use the raw pointer's
/// `load(fromByteOffset:as:)` and `storeBytes(of:toByteOffset:as:)` methods
/// to read and write values.
///
/// let rawPointer = UnsafeMutableRawPointer(uint64Pointer)
/// let fullInteger = rawPointer.load(as: UInt64.self) // OK
/// let firstByte = rawPointer.load(as: UInt8.self) // OK
///
/// Performing Typed Pointer Arithmetic
/// ===================================
///
/// Pointer arithmetic with a typed pointer is counted in strides of the
/// pointer's `Pointee` type. When you add to or subtract from an `UnsafeMutablePointer`
/// instance, the result is a new pointer of the same type, offset by that
/// number of instances of the `Pointee` type.
///
/// // 'intPointer' points to memory initialized with [10, 20, 30, 40]
/// let intPointer: UnsafeMutablePointer<Int> = ...
///
/// // Load the first value in memory
/// let x = intPointer.pointee
/// // x == 10
///
/// // Load the third value in memory
/// let offsetPointer = intPointer + 2
/// let y = offsetPointer.pointee
/// // y == 30
///
/// You can also use subscript notation to access the value in memory at a
/// specific offset.
///
/// let z = intPointer[2]
/// // z == 30
///
/// Implicit Casting and Bridging
/// =============================
///
/// When calling a function or method with an `UnsafeMutablePointer` parameter, you can pass
/// an instance of that specific pointer type or use Swift's implicit bridging
/// to pass a compatible pointer.
///
/// For example, the `printInt(atAddress:)` function in the following code
/// sample expects an `UnsafeMutablePointer<Int>` instance as its first parameter:
///
/// func printInt(atAddress p: UnsafeMutablePointer<Int>) {
/// print(p.pointee)
/// }
///
/// As is typical in Swift, you can call the `printInt(atAddress:)` function
/// with an `UnsafeMutablePointer` instance. This example passes `intPointer`, a mutable
/// pointer to an `Int` value, to `print(address:)`.
///
/// printInt(atAddress: intPointer)
/// // Prints "42"
///
/// Alternatively, you can use Swift's *implicit bridging* to pass a pointer to
/// an instance or to the elements of an array. The following example passes a
/// pointer to the `value` variable by using inout syntax:
///
/// var value: Int = 23
/// printInt(atAddress: &value)
/// // Prints "23"
///
/// A mutable pointer to the elements of an array is implicitly created when
/// you pass the array using inout syntax. This example uses implicit bridging
/// to pass a pointer to the elements of `numbers` when calling
/// `printInt(atAddress:)`.
///
/// var numbers = [5, 10, 15, 20]
/// printInt(atAddress: &numbers)
/// // Prints "5"
///
/// No matter which way you call `printInt(atAddress:)`, Swift's type safety
/// guarantees that you can only pass a pointer to the type required by the
/// function---in this case, a pointer to an `Int`.
///
/// - Important: The pointer created through implicit bridging of an instance
/// or of an array's elements is only valid during the execution of the
/// called function. Escaping the pointer to use after the execution of the
/// function is undefined behavior. In particular, do not use implicit
/// bridging when calling an `UnsafeMutablePointer` initializer.
///
/// var number = 5
/// let numberPointer = UnsafeMutablePointer<Int>(&number)
/// // Accessing 'numberPointer' is undefined behavior.
@frozen // unsafe-performance
public struct UnsafeMutablePointer<Pointee: ~Copyable>: Copyable {
/// The underlying raw (untyped) pointer.
@_preInverseGenerics
public let _rawValue: Builtin.RawPointer
/// Creates an `UnsafeMutablePointer` from a builtin raw pointer.
@_transparent
@_preInverseGenerics
public init(_ _rawValue: Builtin.RawPointer) {
self._rawValue = _rawValue
}
}
@available(*, unavailable)
extension UnsafeMutablePointer: Sendable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafeMutablePointer: _Pointer where Pointee: ~Copyable {
/// A type that represents the distance between two pointers.
public typealias Distance = Int
}
@_preInverseGenerics
extension UnsafeMutablePointer: Equatable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafeMutablePointer: Hashable where Pointee: ~Copyable {
// Note: This explicit `hashValue` applies @_preInverseGenerics to emulate the
// original (pre-6.0) compiler-synthesized version.
@_preInverseGenerics
public var hashValue: Int {
_hashValue(for: self)
}
}
@_preInverseGenerics
extension UnsafeMutablePointer: Comparable where Pointee: ~Copyable {}
@_preInverseGenerics
extension UnsafeMutablePointer: Strideable where Pointee: ~Copyable {}
#if !$Embedded
@_preInverseGenerics
extension UnsafeMutablePointer: CustomDebugStringConvertible
where Pointee: ~Copyable {}
#endif
#if SWIFT_ENABLE_REFLECTION
@_preInverseGenerics
extension UnsafeMutablePointer: CustomReflectable where Pointee: ~Copyable {}
#endif
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Creates a mutable typed pointer referencing the same memory as the given
/// immutable pointer.
///
/// - Parameter other: The immutable pointer to convert.
@_transparent
@_preInverseGenerics
public init(@_nonEphemeral mutating other: UnsafePointer<Pointee>) {
self._rawValue = other._rawValue
}
/// Creates a mutable typed pointer referencing the same memory as the given
/// immutable pointer.
///
/// - Parameter other: The immutable pointer to convert. If `other` is `nil`,
/// the result is `nil`.
@_transparent
@_preInverseGenerics
public init?(@_nonEphemeral mutating other: UnsafePointer<Pointee>?) {
guard let unwrapped = other else { return nil }
self.init(mutating: unwrapped)
}
/// Creates a mutable typed pointer referencing the same memory as the
/// given mutable pointer.
///
/// - Parameter other: The pointer to convert.
@_transparent
@_preInverseGenerics
public init(@_nonEphemeral _ other: UnsafeMutablePointer<Pointee>) {
self._rawValue = other._rawValue
}
/// Creates a mutable typed pointer referencing the same memory as the
/// given mutable pointer.
///
/// - Parameter other: The pointer to convert. If `other` is `nil`, the
/// result is `nil`.
@_transparent
@_preInverseGenerics
public init?(@_nonEphemeral _ other: UnsafeMutablePointer<Pointee>?) {
guard let unwrapped = other else { return nil }
self.init(unwrapped)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Allocates uninitialized memory for the specified number of instances of
/// type `Pointee`.
///
/// The resulting pointer references a region of memory that is bound to
/// `Pointee` and is `count * MemoryLayout<Pointee>.stride` bytes in size.
///
/// The following example allocates enough new memory to store four `Int`
/// instances and then initializes that memory with the elements of a range.
///
/// let intPointer = UnsafeMutablePointer<Int>.allocate(capacity: 4)
/// for i in 0..<4 {
/// (intPointer + i).initialize(to: i)
/// }
/// print(intPointer.pointee)
/// // Prints "0"
///
/// When you allocate memory, always remember to deallocate once you're
/// finished.
///
/// intPointer.deallocate()
///
/// - Parameter count: The amount of memory to allocate, counted in instances
/// of `Pointee`.
@inlinable
@_preInverseGenerics
public static func allocate(
capacity count: Int
) -> UnsafeMutablePointer<Pointee> {
let size = MemoryLayout<Pointee>.stride * count
// For any alignment <= _minAllocationAlignment, force alignment = 0.
// This forces the runtime's "aligned" allocation path so that
// deallocation does not require the original alignment.
//
// The runtime guarantees:
//
// align == 0 || align > _minAllocationAlignment:
// Runtime uses "aligned allocation".
//
// 0 < align <= _minAllocationAlignment:
// Runtime may use either malloc or "aligned allocation".
var align = Builtin.alignof(Pointee.self)
if Int(align) <= _minAllocationAlignment() {
align = (0)._builtinWordValue
}
let rawPtr = Builtin.allocRaw(size._builtinWordValue, align)
Builtin.bindMemory(rawPtr, count._builtinWordValue, Pointee.self)
return UnsafeMutablePointer(rawPtr)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Deallocates the memory block previously allocated at this pointer.
///
/// This pointer must be a pointer to the start of a previously allocated
/// memory block. The memory must not be initialized or `Pointee` must be a
/// trivial type.
@inlinable
@_preInverseGenerics
public func deallocate() {
// Passing zero alignment to the runtime forces "aligned
// deallocation". Since allocation via `UnsafeMutable[Raw][Buffer]Pointer`
// always uses the "aligned allocation" path, this ensures that the
// runtime's allocation and deallocation paths are compatible.
Builtin.deallocRaw(_rawValue, (-1)._builtinWordValue, (0)._builtinWordValue)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Reads or updates the instance referenced by this pointer.
///
/// When reading from the `pointee` property, the instance referenced by this
/// pointer must already be initialized. When `pointee` is used as the left
/// side of an assignment, the instance is updated. The instance must
/// be initialized or this pointer's `Pointee` type must be a trivial type.
///
/// Uninitialized memory cannot be initialized to a nontrivial type
/// using `pointee`. Instead, use an initializing method, such as
/// `initialize(to:)`.
@_alwaysEmitIntoClient
public var pointee: Pointee {
@_transparent unsafeAddress {
return UnsafePointer(self)
}
@_transparent nonmutating unsafeMutableAddress {
return self
}
}
}
@_disallowFeatureSuppression(NoncopyableGenerics)
extension UnsafeMutablePointer {
// This preserves the ABI of the original (pre-6.0) `pointee` property that
// used to export a getter. The current one above would export a read
// accessor, if it wasn't @_alwaysEmitIntoClient.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@usableFromInline
internal var pointee: Pointee {
@_transparent unsafeAddress {
return UnsafePointer(self)
}
@_transparent nonmutating unsafeMutableAddress {
return self
}
}
}
extension UnsafeMutablePointer {
/// Initializes this pointer's memory with the specified number of
/// consecutive copies of the given value.
///
/// The destination memory must be uninitialized or the pointer's `Pointee`
/// must be a trivial type. After a call to `initialize(repeating:count:)`,
/// the memory referenced by this pointer is initialized.
///
/// - Parameters:
/// - repeatedValue: The instance to initialize this pointer's memory with.
/// - count: The number of consecutive copies of `newValue` to initialize.
/// `count` must not be negative.
@inlinable
public func initialize(repeating repeatedValue: Pointee, count: Int) {
// FIXME: add tests (since the `count` has been added)
_debugPrecondition(count >= 0,
"UnsafeMutablePointer.initialize(repeating:count:): negative count")
// Must not use `initializeFrom` with a `Collection` as that will introduce
// a cycle.
for offset in 0..<count {
Builtin.initialize(repeatedValue, (self + offset)._rawValue)
}
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Initializes this pointer's memory with a single instance of the given
/// value.
///
/// The destination memory must be uninitialized or the pointer's `Pointee`
/// must be a trivial type. After a call to `initialize(to:)`, the memory
/// referenced by this pointer is initialized. Calling this method is roughly
/// equivalent to calling `initialize(repeating:count:)` with a `count` of 1.
///
/// - Parameters:
/// - value: The instance to initialize this pointer's pointee to.
@_alwaysEmitIntoClient
public func initialize(to value: consuming Pointee) {
Builtin.initialize(value, self._rawValue)
}
}
extension UnsafeMutablePointer {
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@usableFromInline
internal func initialize(to value: Pointee) { // Note: `value` is __shared!
Builtin.initialize(value, self._rawValue)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Retrieves and returns the referenced instance, returning the pointer's
/// memory to an uninitialized state.
///
/// Calling the `move()` method on a pointer `p` that references memory of
/// type `T` is equivalent to the following code, aside from any cost and
/// incidental side effects of copying and destroying the value:
///
/// let value: T = {
/// defer { p.deinitialize(count: 1) }
/// return p.pointee
/// }()
///
/// The memory referenced by this pointer must be initialized. After calling
/// `move()`, the memory is uninitialized.
///
/// - Returns: The instance referenced by this pointer.
@inlinable
@_preInverseGenerics
public func move() -> Pointee {
return Builtin.take(_rawValue)
}
}
extension UnsafeMutablePointer {
/// Update this pointer's initialized memory with the specified number of
/// consecutive copies of the given value.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be initialized or
/// `Pointee` must be a trivial type. After calling
/// `update(repeating:count:)`, the region is initialized.
///
/// - Parameters:
/// - repeatedValue: The value used when updating this pointer's memory.
/// - count: The number of consecutive elements to update.
/// `count` must not be negative.
@inlinable
@_silgen_name("$sSp6assign9repeating5countyx_SitF")
public func update(repeating repeatedValue: Pointee, count: Int) {
_debugPrecondition(count >= 0, "UnsafeMutablePointer.update(repeating:count:) with negative count")
for i in 0..<count {
self[i] = repeatedValue
}
}
@_alwaysEmitIntoClient
@available(*, deprecated, renamed: "update(repeating:count:)")
@_silgen_name("_swift_se0370_UnsafeMutablePointer_assign_repeating_count")
public func assign(repeating repeatedValue: Pointee, count: Int) {
update(repeating: repeatedValue, count: count)
}
}
extension UnsafeMutablePointer {
/// Update this pointer's initialized memory with the specified number of
/// instances, copied from the given pointer's memory.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be initialized or
/// `Pointee` must be a trivial type. After calling
/// `update(from:count:)`, the region is initialized.
///
/// - Note: Returns without performing work if `self` and `source` are equal.
///
/// - Parameters:
/// - source: A pointer to at least `count` initialized instances of type
/// `Pointee`. The memory regions referenced by `source` and this
/// pointer may overlap.
/// - count: The number of instances to copy from the memory referenced by
/// `source` to this pointer's memory. `count` must not be negative.
@inlinable
@_silgen_name("$sSp6assign4from5countySPyxG_SitF")
public func update(from source: UnsafePointer<Pointee>, count: Int) {
_debugPrecondition(
count >= 0, "UnsafeMutablePointer.update with negative count")
if UnsafePointer(self) < source || UnsafePointer(self) >= source + count {
// assign forward from a disjoint or following overlapping range.
Builtin.assignCopyArrayFrontToBack(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// This builtin is equivalent to:
// for i in 0..<count {
// self[i] = source[i]
// }
}
else if UnsafePointer(self) != source {
// assign backward from a non-following overlapping range.
Builtin.assignCopyArrayBackToFront(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// This builtin is equivalent to:
// var i = count-1
// while i >= 0 {
// self[i] = source[i]
// i -= 1
// }
}
}
@_alwaysEmitIntoClient
@available(*, deprecated, renamed: "update(from:count:)")
@_silgen_name("_swift_se0370_UnsafeMutablePointer_assign_from_count")
public func assign(from source: UnsafePointer<Pointee>, count: Int) {
update(from: source, count: count)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Moves instances from initialized source memory into the uninitialized
/// memory referenced by this pointer, leaving the source memory
/// uninitialized and the memory referenced by this pointer initialized.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be uninitialized or
/// `Pointee` must be a trivial type. After calling
/// `moveInitialize(from:count:)`, the region is initialized and the memory
/// region `source..<(source + count)` is uninitialized.
///
/// - Note: Returns without performing work if `self` and `source` are equal.
///
/// - Parameters:
/// - source: A pointer to the values to copy. The memory region
/// `source..<(source + count)` must be initialized. The memory regions
/// referenced by `source` and this pointer may overlap.
/// - count: The number of instances to move from `source` to this
/// pointer's memory. `count` must not be negative.
@inlinable
@_preInverseGenerics
public func moveInitialize(
@_nonEphemeral from source: UnsafeMutablePointer, count: Int
) {
_debugPrecondition(
count >= 0, "UnsafeMutablePointer.moveInitialize with negative count")
if self < source || self >= source + count {
// initialize forward from a disjoint or following overlapping range.
Builtin.takeArrayFrontToBack(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// This builtin is equivalent to:
// for i in 0..<count {
// (self + i).initialize(to: (source + i).move())
// }
}
else if self != source {
// initialize backward from a non-following overlapping range.
Builtin.takeArrayBackToFront(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// This builtin is equivalent to:
// var src = source + count
// var dst = self + count
// while dst != self {
// (--dst).initialize(to: (--src).move())
// }
}
}
}
extension UnsafeMutablePointer {
/// Initializes the memory referenced by this pointer with the values
/// starting at the given pointer.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be uninitialized or
/// `Pointee` must be a trivial type. After calling
/// `initialize(from:count:)`, the region is initialized.
///
/// - Note: The source and destination memory regions must not overlap.
///
/// - Parameters:
/// - source: A pointer to the values to copy. The memory region
/// `source..<(source + count)` must be initialized. The memory regions
/// referenced by `source` and this pointer must not overlap.
/// - count: The number of instances to move from `source` to this
/// pointer's memory. `count` must not be negative.
@inlinable
public func initialize(from source: UnsafePointer<Pointee>, count: Int) {
_debugPrecondition(
count >= 0, "UnsafeMutablePointer.initialize with negative count")
_debugPrecondition(
UnsafePointer(self) + count <= source ||
source + count <= UnsafePointer(self),
"UnsafeMutablePointer.initialize overlapping range")
Builtin.copyArray(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// This builtin is equivalent to:
// for i in 0..<count {
// (self + i).initialize(to: source[i])
// }
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Update this pointer's initialized memory by moving the specified number
/// of instances the source pointer's memory, leaving the source memory
/// uninitialized.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be initialized or
/// `Pointee` must be a trivial type. After calling
/// `moveUpdate(from:count:)`, the region is initialized and the memory
/// region `source..<(source + count)` is uninitialized.
///
/// - Note: The source and destination memory regions must not overlap.
///
/// - Parameters:
/// - source: A pointer to the values to be moved. The memory region
/// `source..<(source + count)` must be initialized. The memory regions
/// referenced by `source` and this pointer must not overlap.
/// - count: The number of instances to move from `source` to this
/// pointer's memory. `count` must not be negative.
@inlinable
@_silgen_name("$sSp10moveAssign4from5countySpyxG_SitF")
@_preInverseGenerics
public func moveUpdate(
@_nonEphemeral from source: UnsafeMutablePointer, count: Int
) {
_debugPrecondition(
count >= 0, "UnsafeMutablePointer.moveUpdate(from:) with negative count")
_debugPrecondition(
self + count <= source || source + count <= self,
"moveUpdate overlapping range")
Builtin.assignTakeArray(
Pointee.self, self._rawValue, source._rawValue, count._builtinWordValue)
// These builtins are equivalent to:
// for i in 0..<count {
// self[i] = (source + i).move()
// }
}
}
extension UnsafeMutablePointer {
@_alwaysEmitIntoClient
@available(*, deprecated, renamed: "moveUpdate(from:count:)")
@_silgen_name("_swift_se0370_UnsafeMutablePointer_moveAssign_from_count")
public func moveAssign(
@_nonEphemeral from source: UnsafeMutablePointer, count: Int
) {
moveUpdate(from: source, count: count)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Deinitializes the specified number of values starting at this pointer.
///
/// The region of memory starting at this pointer and covering `count`
/// instances of the pointer's `Pointee` type must be initialized. After
/// calling `deinitialize(count:)`, the memory is uninitialized, but still
/// bound to the `Pointee` type.
///
/// - Parameter count: The number of instances to deinitialize. `count` must
/// not be negative.
/// - Returns: A raw pointer to the same address as this pointer. The memory
/// referenced by the returned raw pointer is still bound to `Pointee`.
@inlinable
@_preInverseGenerics
@discardableResult
public func deinitialize(count: Int) -> UnsafeMutableRawPointer {
_debugPrecondition(count >= 0, "UnsafeMutablePointer.deinitialize with negative count")
// TODO: IRGen optimization when `count` value is statically known to be 1,
// then call `Builtin.destroy(Pointee.self, _rawValue)` instead.
Builtin.destroyArray(Pointee.self, _rawValue, count._builtinWordValue)
return UnsafeMutableRawPointer(self)
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Executes the given closure while temporarily binding memory to
/// the specified number of instances of the given type.
///
/// Use this method when you have a pointer to memory bound to one type and
/// you need to access that memory as instances of another type. Accessing
/// memory as a type `T` requires that the memory be bound to that type. A
/// memory location may only be bound to one type at a time, so accessing
/// the same memory as an unrelated type without first rebinding the memory
/// is undefined.
///
/// The region of memory that starts at this pointer and covers `count`
/// strides of `T` instances must be bound to `Pointee`.
/// Any instance of `T` within the re-bound region may be initialized or
/// uninitialized. Every instance of `Pointee` overlapping with a given
/// instance of `T` should have the same initialization state (i.e.
/// initialized or uninitialized.) Accessing a `T` whose underlying
/// `Pointee` storage is in a mixed initialization state shall be
/// undefined behaviour.
///
/// The following example temporarily rebinds the memory of a `UInt64`
/// pointer to `Int64`, then modifies the signed integer.
///
/// let uint64Pointer: UnsafeMutablePointer<UInt64> = fetchValue()
/// uint64Pointer.withMemoryRebound(to: Int64.self, capacity: 1) {
/// $0.pointee.negate()
/// }
///
/// Because this pointer's memory is no longer bound to its `Pointee` type
/// while the `body` closure executes, do not access memory using the
/// original pointer from within `body`. Instead, use the `body` closure's
/// pointer argument to access the values in memory as instances of type
/// `T`.
///
/// After executing `body`, this method rebinds memory back to the original
/// `Pointee` type.
///
/// - Note: Only use this method to rebind the pointer's memory to a type
/// that is layout compatible with the `Pointee` type. The stride of the
/// temporary type (`T`) may be an integer multiple or a whole fraction
/// of `Pointee`'s stride, for example to point to one element of
/// an aggregate.
/// To bind a region of memory to a type that does not match these
/// requirements, convert the pointer to a raw pointer and use the
/// `bindMemory(to:)` method.
/// If `T` and `Pointee` have different alignments, this pointer
/// must be aligned with the larger of the two alignments.
///
/// - Parameters:
/// - type: The type to temporarily bind the memory referenced by this
/// pointer. The type `T` must be layout compatible
/// with the pointer's `Pointee` type.
/// - count: The number of instances of `T` in the re-bound region.
/// - body: A closure that takes a mutable typed pointer to the
/// same memory as this pointer, only bound to type `T`. The closure's
/// pointer argument is valid only for the duration of the closure's
/// execution. If `body` has a return value, that value is also used as
/// the return value for the `withMemoryRebound(to:capacity:_:)` method.
/// - pointer: The pointer temporarily bound to `T`.
/// - Returns: The return value, if any, of the `body` closure parameter.
@_alwaysEmitIntoClient
public func withMemoryRebound<T: ~Copyable, E: Error, Result: ~Copyable>(
to type: T.Type,
capacity count: Int,
_ body: (_ pointer: UnsafeMutablePointer<T>) throws(E) -> Result
) throws(E) -> Result {
_debugPrecondition(
Int(bitPattern: .init(_rawValue)) & (MemoryLayout<T>.alignment-1) == 0 &&
( count == 1 ||
( MemoryLayout<Pointee>.stride > MemoryLayout<T>.stride
? MemoryLayout<Pointee>.stride % MemoryLayout<T>.stride == 0
: MemoryLayout<T>.stride % MemoryLayout<Pointee>.stride == 0
)
),
"self must be a properly aligned pointer for types Pointee and T"
)
let binding = Builtin.bindMemory(_rawValue, count._builtinWordValue, T.self)
defer { Builtin.rebindMemory(_rawValue, binding) }
return try body(.init(_rawValue))
}
}
extension UnsafeMutablePointer {
// This obsolete implementation uses the expected mangled name of
// `withMemoryRebound<T, Result>(to:capacity:_:)`, and provides an entry point
// for any binary linked against the stdlib binary for Swift 5.6 and older.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@_silgen_name("$sSp17withMemoryRebound2to8capacity_qd_0_qd__m_Siqd_0_Spyqd__GKXEtKr0_lF")
@usableFromInline
internal func _legacy_se0333_withMemoryRebound<T, Result>(
to type: T.Type,
capacity count: Int,
_ body: (UnsafeMutablePointer<T>) throws -> Result
) rethrows -> Result {
let binding = Builtin.bindMemory(_rawValue, count._builtinWordValue, T.self)
defer { Builtin.rebindMemory(_rawValue, binding) }
return try body(.init(_rawValue))
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
/// Reads or updates the pointee at the specified offset from this pointer.
///
/// For a pointer `p`, the memory at `p + i` must be initialized when reading
/// the value by using the subscript. When the subscript is used as the left
/// side of an assignment, the memory at `p + i` is updated. The memory must
/// be initialized or the pointer's `Pointee` type must be a trivial type.
///
/// Uninitialized memory cannot be initialized to a nontrivial type
/// using this subscript. Instead, use an initializing method, such as
/// `initialize(to:)`.
///
/// - Parameter i: The offset from this pointer at which to access an
/// instance, measured in strides of the pointer's `Pointee` type.
@_alwaysEmitIntoClient
public subscript(i: Int) -> Pointee {
@_transparent
unsafeAddress {
return UnsafePointer(self + i)
}
@_transparent
nonmutating unsafeMutableAddress {
return self + i
}
}
}
@_disallowFeatureSuppression(NoncopyableGenerics)
extension UnsafeMutablePointer {
// This preserves the ABI of the original (pre-6.0) subscript that used to
// export a getter. The current one above would export a read accessor, if it
// wasn't @_alwaysEmitIntoClient.
@_spi(SwiftStdlibLegacyABI) @available(swift, obsoleted: 1)
@usableFromInline
internal subscript(i: Int) -> Pointee {
@_transparent
unsafeAddress {
return UnsafePointer(self + i)
}
@_transparent
nonmutating unsafeMutableAddress {
return self + i
}
}
}
extension UnsafeMutablePointer {
/// Obtain a pointer to the stored property referred to by a key path.
///
/// If the key path represents a computed property,
/// this function will return `nil`.
///
/// - Parameter property: A `KeyPath` whose `Root` is `Pointee`.
/// - Returns: A pointer to the stored property represented
/// by the key path, or `nil`.
@_alwaysEmitIntoClient
#if $Embedded
@_transparent
#endif
public func pointer<Property>(
to property: KeyPath<Pointee, Property>
) -> UnsafePointer<Property>? {
guard let o = property._storedInlineOffset else { return nil }
_internalInvariant(o >= 0)
_debugPrecondition(
o == 0 || UnsafeRawPointer(self) < UnsafeRawPointer(bitPattern: 0 &- o)!,
"Overflow in pointer arithmetic"
)
return .init(Builtin.gepRaw_Word(_rawValue, o._builtinWordValue))
}
/// Obtain a mutable pointer to the stored property referred to by a key path.
///
/// If the key path represents a computed property,
/// this function will return `nil`.
///
/// - Parameter property: A `WritableKeyPath` whose `Root` is `Pointee`.
/// - Returns: A mutable pointer to the stored property represented
/// by the key path, or `nil`.
@_alwaysEmitIntoClient
#if $Embedded
@_transparent
#endif
public func pointer<Property>(
to property: WritableKeyPath<Pointee, Property>
) -> UnsafeMutablePointer<Property>? {
guard let o = property._storedInlineOffset else { return nil }
_internalInvariant(o >= 0)
_debugPrecondition(
o == 0 || UnsafeRawPointer(self) < UnsafeRawPointer(bitPattern: 0 &- o)!,
"Overflow in pointer arithmetic"
)
return .init(Builtin.gepRaw_Word(_rawValue, o._builtinWordValue))
}
}
extension UnsafeMutablePointer where Pointee: ~Copyable {
@inlinable // unsafe-performance
@_preInverseGenerics
internal static var _max: UnsafeMutablePointer {
return UnsafeMutablePointer(
bitPattern: 0 as Int &- MemoryLayout<Pointee>.stride
)._unsafelyUnwrappedUnchecked
}
}
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