Swift3 AURenderCallback中的UnsafeMutablePointer_Swift3_Core Audio_Unsafemutablepointer

Swift3 AURenderCallback中的UnsafeMutablePointer

swift3

Swift3 AURenderCallback中的UnsafeMutablePointer,swift3,core-audio,unsafemutablepointer,Swift3,Core Audio,Unsafemutablepointer,我不明白，我应该如何在Swift 3中使用unsafemeutablepointer。尤其是在AURenderCallback中我尝试以下代码： import Foundation import AudioToolbox let sineFrequency = 880.0 // MARK: User data struct struct SineWavePlayer { var outputUnit: AudioUnit? = nil var startingFrameCo

我不明白，我应该如何在Swift 3中使用

unsafemeutablepointer

。尤其是在

AURenderCallback

中

我尝试以下代码：

import Foundation
import AudioToolbox

let sineFrequency = 880.0

// MARK: User data struct
struct SineWavePlayer {
    var outputUnit: AudioUnit? = nil
    var startingFrameCount: Double = 0
}

// MARK: Callback function
let SineWaveRenderProc: AURenderCallback = {(inRefCon, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, ioData) -> OSStatus in

    var player = UnsafeMutablePointer<SineWavePlayer>(inRefCon)


    var j = player.pointee.startingFrameCount
    let cycleLength = 44100 / sineFrequency

    for frame in 0..<inNumberFrames {
        var buffers = UnsafeMutableAudioBufferListPointer(ioData)

        UnsafeMutablePointer<Float32>(buffers[0].mData)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))
        UnsafeMutablePointer<Float32>(buffers[1].mData)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))

        // Or iterate through array:
//        for buffer in buffers {
//            UnsafeMutablePointer<Float32>(buffer.mData)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))
//        }

        j++
        if j > cycleLength {
            j -= cycleLength
        }
    }

    player.pointee.startingFrameCount = j
    return noErr
}

// MARK: Utility function
func CheckError(_ error: OSStatus, operation: String) {
    guard error != noErr else {
        return
    }

    var result: String = ""
    var char = Int(error.bigEndian)

    for _ in 0..<4 {
        guard isprint(Int32(char&255)) == 1 else {
            result = "\(error)"
            break
        }
        result.append(String(describing: UnicodeScalar(char&255)))
        char = char/256
    }

    print("Error: \(operation) (\(result))")

    exit(1)
}

func CreateAndConnectOutputUnit(_ player: inout SineWavePlayer) {
    // Generate a description that matches the output device (speakers)
    var outputcd = AudioComponentDescription(componentType: kAudioUnitType_Output, componentSubType: kAudioUnitSubType_DefaultOutput, componentManufacturer: kAudioUnitManufacturer_Apple, componentFlags: 0, componentFlagsMask: 0)

    let comp = AudioComponentFindNext(nil, &outputcd)

    if comp == nil {
        print("Can't get output unit")
        exit(-1)
    }

    CheckError(AudioComponentInstanceNew(comp!, &player.outputUnit),
        operation: "Couldn't open component for outputUnit")

    // Register the render callback
    var input = AURenderCallbackStruct(inputProc: SineWaveRenderProc, inputProcRefCon: &player)

    CheckError(AudioUnitSetProperty(player.outputUnit!, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &input, UInt32(MemoryLayout<AURenderCallbackStruct>.size)),
        operation: "AudioUnitSetProperty failed")

    // Initialize the unit
    CheckError(AudioUnitInitialize(player.outputUnit!),
        operation: "Couldn't initialize output unit")
}

func main() {
    var player = SineWavePlayer()

    // Set up output unit and callback
    CreateAndConnectOutputUnit(&player)

    // Start playing
    CheckError(AudioOutputUnitStart(player.outputUnit!),
        operation: "Couldn't start output unit")

    // Play for 5 seconds
    sleep(5)

    // Clean up
    AudioOutputUnitStop(player.outputUnit!)
    AudioUnitUninitialize(player.outputUnit!)
    AudioComponentInstanceDispose(player.outputUnit!)
}

main()

<代码>导入基础导入音频工具箱设正弦频率=880.0 //标记：用户数据结构结构正弦波播放器{ var输出单位：音频单位？=零 var startingFrameCount:Double=0 } //标记：回调函数让SineWaveRenderProc:AURenderCallback={（inRefCon、ioActionFlags、inTimeStamp、inBusNumber、inNumberFrames、ioData）->OSStatus in var player=unsafemeutablepointer（inRefCon） var j=player.pointee.startingFrameCount 让循环长度=44100/正弦频率对于0中的帧，循环长度{ j-=循环长度 } } player.pointee.startingFrameCount=j 返回noErr } //标记：效用函数 func CheckError（error:OSStatus，operation:String）{ 保护错误！=noErr else{ 返回 } 变量结果：String=“” var char=Int（error.bigEndian）

对于Swift 3中的u in 0..，不能使用初始值设定项转换指针类型。在您的情况下，refcon中的

类型是UnsafemeutableRawPointer
，因此需要使用assumingMemoryBound（to:）
方法
还有一点，传递给回调函数的播放器
的地址需要在声音播放时始终保持稳定，从inout参数（由&
前缀指定）获取的地址不满足此要求
上面的两件事是固定的，您的代码应该是这样的：
import Foundation
import AudioToolbox

let sineFrequency = 880.0

// MARK: User data struct
struct SineWavePlayer {
    var outputUnit: AudioUnit? = nil
    var startingFrameCount: Double = 0
}

// MARK: Callback function
let SineWaveRenderProc: AURenderCallback = {(inRefCon, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, ioData) -> OSStatus in

    var player = inRefCon.assumingMemoryBound(to: SineWavePlayer.self)


    var j = player.pointee.startingFrameCount
    let cycleLength = 44100 / sineFrequency

    for frame in 0..<inNumberFrames {
        var buffers = UnsafeMutableAudioBufferListPointer(ioData)

        buffers?[0].mData?.assumingMemoryBound(to: Float32.self)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))
        buffers?[1].mData?.assumingMemoryBound(to: Float32.self)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))

        j += 1
        if j > cycleLength {
            j -= cycleLength
        }
    }

    player.pointee.startingFrameCount = j
    return noErr
}

// MARK: Utility function
func CheckError(_ error: OSStatus, operation: String) {
    guard error != noErr else {
        return
    }

    var result: String = ""
    var char = Int(error.bigEndian)

    for _ in 0..<4 {
        guard isprint(Int32(char&255)) == 1 else {
            result = "\(error)"
            break
        }
        result.append(String(describing: UnicodeScalar(char&255)))
        char = char/256
    }

    print("Error: \(operation) (\(result))")

    exit(1)
}

func CreateAndConnectOutputUnit(_ playerPtr: UnsafeMutablePointer<SineWavePlayer>) {
    // Generate a description that matches the output device (speakers)
    var outputcd = AudioComponentDescription(componentType: kAudioUnitType_Output, componentSubType: kAudioUnitSubType_DefaultOutput, componentManufacturer: kAudioUnitManufacturer_Apple, componentFlags: 0, componentFlagsMask: 0)

    let comp = AudioComponentFindNext(nil, &outputcd)

    if comp == nil {
        print("Can't get output unit")
        exit(-1)
    }

    CheckError(AudioComponentInstanceNew(comp!, &playerPtr.pointee.outputUnit),
               operation: "Couldn't open component for outputUnit")

    // Register the render callback
    var input = AURenderCallbackStruct(inputProc: SineWaveRenderProc, inputProcRefCon: playerPtr)

    CheckError(AudioUnitSetProperty(playerPtr.pointee.outputUnit!, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &input, UInt32(MemoryLayout<AURenderCallbackStruct>.size)),
               operation: "AudioUnitSetProperty failed")

    // Initialize the unit
    CheckError(AudioUnitInitialize(playerPtr.pointee.outputUnit!),
               operation: "Couldn't initialize output unit")
}

func main() {
    let playerPtr = UnsafeMutablePointer<SineWavePlayer>.allocate(capacity: 1)
    defer {playerPtr.deallocate(capacity: 1)}
    playerPtr.initialize(to: SineWavePlayer())
    defer {playerPtr.deinitialize()}

    // Set up output unit and callback
    CreateAndConnectOutputUnit(playerPtr)

    // Start playing
    CheckError(AudioOutputUnitStart(playerPtr.pointee.outputUnit!),
               operation: "Couldn't start output unit")

    // Play for 5 seconds
    sleep(5)

    // Clean up
    AudioOutputUnitStop(playerPtr.pointee.outputUnit!)
    AudioUnitUninitialize(playerPtr.pointee.outputUnit!)
    AudioComponentInstanceDispose(playerPtr.pointee.outputUnit!)
}

<代码>导入基础
导入音频工具箱
设正弦频率=880.0
//标记：用户数据结构
结构正弦波播放器{
var输出单位：音频单位？=零
var startingFrameCount:Double=0
}
//标记：回调函数
让SineWaveRenderProc:AURenderCallback={（inRefCon、ioActionFlags、inTimeStamp、inBusNumber、inNumberFrames、ioData）->OSStatus in
var player=inRefCon.assumingmemorybind（到：SineWavePlayer.self）
var j=player.pointee.startingFrameCount
让循环长度=44100/正弦频率
对于0中的帧，循环长度{
j-=循环长度
}
}
player.pointee.startingFrameCount=j
返回noErr
}
//标记：效用函数
func CheckError（error:OSStatus，operation:String）{
保护错误！=noErr else{
返回
}
变量结果：String=“”
var char=Int（error.bigEndian）
对于0中的uu。您可以使用与中相同的方法。@MartinR，SineWavePlayer
是struct，因此相同的方法不起作用。@OOPer:refcon是一个指针，因此使SineWavePlayer
类更有意义。您能写几行代码吗？应该是什么样的？@MartinR，refcon是类型为vo的通用指针id*
。将对象引用传递到void*是一种黑客行为。我真的怀疑这种黑客行为是否更有意义。谢谢！现在我明白了。现在一切都好了！
import Foundation
import AudioToolbox

let sineFrequency = 880.0

// MARK: User data struct
struct SineWavePlayer {
    var outputUnit: AudioUnit? = nil
    var startingFrameCount: Double = 0
}

// MARK: Callback function
let SineWaveRenderProc: AURenderCallback = {(inRefCon, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, ioData) -> OSStatus in

    var player = inRefCon.assumingMemoryBound(to: SineWavePlayer.self)


    var j = player.pointee.startingFrameCount
    let cycleLength = 44100 / sineFrequency

    for frame in 0..<inNumberFrames {
        var buffers = UnsafeMutableAudioBufferListPointer(ioData)

        buffers?[0].mData?.assumingMemoryBound(to: Float32.self)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))
        buffers?[1].mData?.assumingMemoryBound(to: Float32.self)[Int(frame)] = Float32(sin(2 * M_PI * (j / cycleLength)))

        j += 1
        if j > cycleLength {
            j -= cycleLength
        }
    }

    player.pointee.startingFrameCount = j
    return noErr
}

// MARK: Utility function
func CheckError(_ error: OSStatus, operation: String) {
    guard error != noErr else {
        return
    }

    var result: String = ""
    var char = Int(error.bigEndian)

    for _ in 0..<4 {
        guard isprint(Int32(char&255)) == 1 else {
            result = "\(error)"
            break
        }
        result.append(String(describing: UnicodeScalar(char&255)))
        char = char/256
    }

    print("Error: \(operation) (\(result))")

    exit(1)
}

func CreateAndConnectOutputUnit(_ playerPtr: UnsafeMutablePointer<SineWavePlayer>) {
    // Generate a description that matches the output device (speakers)
    var outputcd = AudioComponentDescription(componentType: kAudioUnitType_Output, componentSubType: kAudioUnitSubType_DefaultOutput, componentManufacturer: kAudioUnitManufacturer_Apple, componentFlags: 0, componentFlagsMask: 0)

    let comp = AudioComponentFindNext(nil, &outputcd)

    if comp == nil {
        print("Can't get output unit")
        exit(-1)
    }

    CheckError(AudioComponentInstanceNew(comp!, &playerPtr.pointee.outputUnit),
               operation: "Couldn't open component for outputUnit")

    // Register the render callback
    var input = AURenderCallbackStruct(inputProc: SineWaveRenderProc, inputProcRefCon: playerPtr)

    CheckError(AudioUnitSetProperty(playerPtr.pointee.outputUnit!, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &input, UInt32(MemoryLayout<AURenderCallbackStruct>.size)),
               operation: "AudioUnitSetProperty failed")

    // Initialize the unit
    CheckError(AudioUnitInitialize(playerPtr.pointee.outputUnit!),
               operation: "Couldn't initialize output unit")
}

func main() {
    let playerPtr = UnsafeMutablePointer<SineWavePlayer>.allocate(capacity: 1)
    defer {playerPtr.deallocate(capacity: 1)}
    playerPtr.initialize(to: SineWavePlayer())
    defer {playerPtr.deinitialize()}

    // Set up output unit and callback
    CreateAndConnectOutputUnit(playerPtr)

    // Start playing
    CheckError(AudioOutputUnitStart(playerPtr.pointee.outputUnit!),
               operation: "Couldn't start output unit")

    // Play for 5 seconds
    sleep(5)

    // Clean up
    AudioOutputUnitStop(playerPtr.pointee.outputUnit!)
    AudioUnitUninitialize(playerPtr.pointee.outputUnit!)
    AudioComponentInstanceDispose(playerPtr.pointee.outputUnit!)
}