Swift转换：错误 - UnsafeMutablePointer

Question

我试图将我的Swift 2代码转换成最新的语法（Swift 3）。我收到以下错误：

Cannot invoke initializer for type 'UnsafeMutablePointer<CUnsignedChar>' with an argument list of type '(UnsafeMutableRawPointer!)

斯威夫特2代码：

let rawData = UnsafeMutablePointer<CUnsignedChar>(calloc(height * width * 4, Int(sizeof(CUnsignedChar)))) 

有人可以帮我解决这个转换语法问题？

Answer 1

calloc返回一个“原始指针”（C中的Swift等效于void *）。 你可以用assumingMemoryBound其转换为一个类型的指针：

let rawData = calloc(width * height, MemoryLayout<CUnsignedChar>.stride).assumingMemoryBound(to: CUnsignedChar.self) 

或者使用UnsafeMutablePointer的allocate()方法：

let rawData = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: width * height) 
rawData.initialize(to: 0, count: width * height) 
// ... 

rawData.deinitialize() 
rawData.deallocate(capacity: width * height)