swift - 在 Swift 中与指向 Int 数组的 C 指针互操作

Question

我有一个具有此功能的遗留代码库:

-(void)foo: (int *)buffer {
  myArray[0] = buffer[0];
  myArray[1] = buffer[1];
  myArray[2] = buffer[2];
  myArray[3] = buffer[3];
}

在Swift中，这个方法是这样写的:

func foo(buffer: UnsafeMutablePointer<Int32>) {
}

int指针现在被认为是 UnsafeMutablePointer<UInt32> .我在访问 buffer 的下标时遇到问题在 swift ；即我不能调用 buffer[0]像这样:

func foo(buffer: UnsafeMutablePointer<Int32>) {
  myArray[0] = buffer[0] // won't compile, buffer treated as Int32
}

出于绝望，即使知道UnsafeMutablePointer<Int32>最终解析为 Int32输入 Swift，我尝试了以下方法:

guard let buffer = buffer.memory as? [Int] else { fatalError() }

guard let buffer = buffer as? [Int] else { fatalError() }

guard let buffer = buffer.memory as? [Int32] else { fatalError() }

guard let buffer = buffer as? [Int32] else { fatalError() }

有人能给我指明正确的方向，让我了解如何像 Objective-C 代码那样访问下标成员吗？

Answer 1

你想多了:

class MyClass {
    var myArray = [Int32](count: 4, repeatedValue: 0)

    func foo(buffer: UnsafeMutablePointer<Int32>) {
        for i in 0..<4 {
            myArray[i] = buffer[i]
        }
    }
}

您可以将 myArray 更改为 [Int32] 以使其匹配 buffer。或者您可以将 buffer 转换为 Int:

myArray[i] = Int(buffer[i])