Pointers Swift中的CMBlockBuffer、UnsafemeutablePointer等

我正在尝试转换苹果的一个代码示例中提供的一些目标C代码：

到目前为止，我得出的结果如下：

func copySampleBuffer() -> CMSampleBuffer? {

    var textLength : Int = 0
    var sampleSize : Int = 0

    if (text != nil) {
        textLength = text!.characters.count
        sampleSize = text!.lengthOfBytesUsingEncoding(NSUTF16StringEncoding)
    }

    var sampleData = [UInt8]()

    // Append text length
    sampleData.append(UInt16(textLength).hiByte())
    sampleData.append(UInt16(textLength).loByte())

    // Append the text
    for char in (text?.utf16)! {
        sampleData.append(char.bigEndian.hiByte())
        sampleData.append(char.bigEndian.loByte())
    }

    if (self.forced) {
        // TODO
    }

    let samplePtr = UnsafeMutablePointer<[UInt8]>.alloc(1)
    samplePtr.memory = sampleData

    var sampleTiming = CMSampleTimingInfo()
    sampleTiming.duration = self.timeRange.duration;
    sampleTiming.presentationTimeStamp = self.timeRange.start;
    sampleTiming.decodeTimeStamp = kCMTimeInvalid;

    let formatDescription = copyFormatDescription()

    let dataBufferUMP = UnsafeMutablePointer<Optional<CMBlockBuffer>>.alloc(1)

    CMBlockBufferCreateWithMemoryBlock(kCFAllocatorDefault, samplePtr, sampleSize, kCFAllocatorMalloc, nil, 0, sampleSize, 0, dataBufferUMP);

    let sampleBufferUMP = UnsafeMutablePointer<Optional<CMSampleBuffer>>.alloc(1)

    CMSampleBufferCreate(kCFAllocatorDefault, dataBufferUMP.memory, true, nil, nil, formatDescription, 1, 1, &sampleTiming, 1, &sampleSize, sampleBufferUMP);

    let sampleBuffer = sampleBufferUMP.memory

    sampleBufferUMP.destroy()
    sampleBufferUMP.dealloc(1)

    dataBufferUMP.destroy()
    dataBufferUMP.dealloc(1)

    samplePtr.destroy()
    //Crash if I call dealloc here
    //Error is: error for object 0x10071e400: pointer being freed was not allocated
    //samplePtr.dealloc(1)

    return sampleBuffer;
}

---

如果您对最适合此功能的Swift 2代码有任何建议，我们将不胜感激。

因此，首先，您需要使用此模式编写代码

class C { deinit { print("I got deinit'd!") } }
struct S { var objectRef:AnyObject? }

func foo() {
    let ptr = UnsafeMutablePointer<S>.alloc(1)
    let o = C()
    let fancy = S(objectRef: o)
    ptr.memory = fancy
    ptr.destroy() //deinit runs here!
    ptr.dealloc(1) //don't leak memory
}
// soon or later this code should crash :-)
(1..<1000).forEach{ i in
    foo()
    print(i)
}

C类{deinit{print（“我得到了deinit！”）}
结构S{var objectRef:AnyObject？}
func foo（）{
设ptr=unsafemeutablepointer.alloc（1）
设o=C（）
设fancy=S（objectRef:o）
记忆=幻想
ptr.destroy（）//Denit在这里运行！
ptr.dealloc（1）//不要泄漏内存
}
//不久或稍后，此代码将崩溃：-）
（1..谢谢。请澄清，alloc表示类型的实例数、数据大小或其他内容？文档并不完全清楚，所有示例都提供“1”作为值。@AndreM实例数
class C { deinit { print("I got deinit'd!") } }
struct S { var objectRef:AnyObject? }

func foo() {
    let ptr = UnsafeMutablePointer<S>.alloc(1)
    let o = C()
    let fancy = S(objectRef: o)
    ptr.memory = fancy
    ptr.destroy() //deinit runs here!
    ptr.dealloc(1) //don't leak memory
}
// soon or later this code should crash :-)
(1..<1000).forEach{ i in
    foo()
    print(i)
}

class C { deinit { print("I got deinit'd!") } }
struct S { var objectRef:AnyObject? }

func foo() {
    let ptr = UnsafeMutablePointer<S>.alloc(1)
    let o = C()
    let fancy = S(objectRef: o)
    ptr.initialize(fancy)
    ptr.destroy()
    ptr.dealloc(1)
}

(1..<1000).forEach{ i in
    foo()
    print(i)
}