objc结构数组快速数组

Question

-(CGPoint*)func
{
    CGPoint* result = calloc(2, sizeof(CGPoint));
    result[0] = ..;
    result[1] = ..;

    return result;
}

how cast this array to swift [CGPoint] ?

Answer 1

You can use UnsafeBufferPointer to cast it as follows

    let pointer: UnsafeMutablePointer<CGPoint> = yourInstance.func()

    let swiftArray = Array(UnsafeBufferPointer(start: pointer, count: 2))

    free(pointer)

EDIT

If you really need to use C arrays, you may want to rewrite the func method to something like:

- (CGPoint*)pointArray:(NSInteger *)length
{
    int arrSize = 2;
    CGPoint* result = calloc(arrSize, sizeof(CGPoint));
    result[0] = ...
    result[1] = ...

    *length = arrSize;

    return result;
}

Then on the Swift side:

    var arrayLength: Int = 0
    let pointer: UnsafeMutablePointer<CGPoint> = yourInstance.pointArray(&arrayLength)

    let swiftArray = Array(UnsafeBufferPointer(start: pointer, count: arrayLength))

    free(pointer)