Using AudioBufferList with Swift

Question

I have a bridging function in Swift, one of whose arguments in C is AudioBufferList *. In Swift this generates an UnsafePointer

Answer 1

I found this by accident. Oddly the type ahead was actually working with Swift when it suggested UnsafeMutableAudioBufferListPointer. Which you can initialize with an UnsafeMutablePointer argument. This type is a MutableCollectionType and provides subscript and generator access to the contained Audio Buffers.

For example you can set an ABL to silence with the following code

func renderCallback(ioData: UnsafeMutablePointer) -> OSStatus {

    let abl = UnsafeMutableAudioBufferListPointer(ioData)

    for buffer in abl {

        memset(buffer.mData, 0, Int(buffer.mDataByteSize))
    }

    return noErr
}