如何从UnsafeMutableRawPointer中获取字节? [英] How to get bytes out of an UnsafeMutableRawPointer?
问题描述
如何将UnsafeMutableRawPointer(Swift 3中的新增功能)指向的一个访问字节(或Int16，float等)从内存中移出，然后由C API(核心音频等)传递给Swift函数
How does one access bytes (or Int16's, floats, etc.) out of memory pointed to by an UnsafeMutableRawPointer (new in Swift 3) handed to a Swift function by a C API (Core Audio, etc.)
推荐答案
load<T>从内存中读取原始字节，并构造一个T类型的值:
load<T> reads raw bytes from memory and constructs a value of type T:
let ptr = ... // Unsafe[Mutable]RawPointer
let i16 = ptr.load(as: UInt16.self)
(可选)以字节偏移:
let i16 = ptr.load(fromByteOffset: 4, as: UInt16.self)
还有assumingMemoryBound()，它可以将Unsafe[Mutable]RawPointer转换为Unsafe[Mutable]Pointer<T>，假设指向的存储器包含类型T的值:
There is also assumingMemoryBound() which converts from a Unsafe[Mutable]RawPointer to a Unsafe[Mutable]Pointer<T>, assuming that the pointed-to memory contains a value of type T:
let i16 = ptr.assumingMemoryBound(to: UInt16.self).pointee
对于值数组，您可以创建缓冲区指针":
For an array of values you can create a "buffer pointer":
let i16bufptr = UnsafeBufferPointer(start: ptr.assumingMemoryBound(to: UInt16.self), count: count)
缓冲区指针可能已经足够满足您的目的，它 是可以下标的，可以类似于数组进行枚举. 如有必要，从缓冲区指针创建一个数组:
A buffer pointer might already be sufficient for your purpose, it is subscriptable and can be enumerated similarly to an array. If necessary, create an array from the buffer pointer:
let i16array = Array(i16bufptr)
如@Hamish所说，有关更多信息和详细信息，请访问
As @Hamish said, more information and details can be found at
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