斯威夫特3铸造问题 - AudioQueue

Question

我想转换为斯威夫特3语法如下代码：

fileprivate func generateTone(_ buffer: AudioQueueBufferRef) { 
     if noteAmplitude == 0 { 
      memset(buffer.pointee.mAudioData, 0, Int(buffer.pointee.mAudioDataBytesCapacity)) 
     } else { 
      let count: Int = Int(buffer.pointee.mAudioDataBytesCapacity)/MemoryLayout<Float32>.size 
      var x: Double = 0 
      var y: Double = 0 
      let audioData = UnsafeMutablePointer<Float32>(buffer.pointee.mAudioData) 

      for frame in 0..<count { 
       x = noteFrame * noteFrequency/kSampleRate 
       y = sin (x * 2.0 * M_PI) * noteAmplitude 
       audioData[frame] = Float32(y) 

       noteAmplitude -= noteDecay 
       if noteAmplitude < 0.0 { 
        noteAmplitude = 0 
       } 

       noteFrame += 1 
      } 
     } 

     buffer.pointee.mAudioDataByteSize = buffer.pointee.mAudioDataBytesCapacity 
    } 

我坚持用：

let audioData = UnsafeMutablePointer<Float32>(buffer.pointee.mAudioData) 

Xcode的抱怨：

无法使用类型为'（UnsafeMutableRawPointer）'的参数列表调用类型为'UnsafeMutablePointer' 的初始值设定项'

该项目可在here

任何帮助将是非常赞赏:)

Answer 1

mAudioData是 “无类型指针”（UnsafeMutableRawPointer），你可以 将它转换为一个带有指针的指针assumingMemoryBound：

let audioData = buffer.pointee.mAudioData.assumingMemoryBound(to: Float32.self) 

有关原始指针的更多信息，请参见SE-0107 UnsafeRawPointer API 。