javier
c5037dd716
This PR contains the work done to update the library and the attached example project to use the Swift 6.4 computer as a minimum supported version and also, to use the latest features introduced in it. Reviewed-on: #1 Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
41 lines
1.7 KiB
Swift
41 lines
1.7 KiB
Swift
extension Sound {
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/// A source rendered by a Swift callback every audio cycle. Create with
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/// `Sound.addSource(stereo:_:)`; it stays alive until removed with `removeSource`.
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public final class CallbackSource: Source {
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let callback: Callback
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/// Keeps sources alive for the C trampoline until removed (`Sound`/`Channel`
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/// `.removeSource`) or their channel is freed.
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nonisolated(unsafe) static var live: [CallbackSource] = []
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/// Drops the reference added by `adopt(pointer:)`.
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static func release(_ source: Source) {
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live.removeAll { $0 === source }
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}
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init(callback: @escaping Callback) {
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self.callback = callback
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super.init(pointer: nil, isOwned: false)
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}
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var contextPointer: UnsafeMutableRawPointer {
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Unmanaged.passUnretained(self).toOpaque()
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}
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static let trampoline: @convention(c) (UnsafeMutableRawPointer?, UnsafeMutablePointer<Int16>?,
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UnsafeMutablePointer<Int16>?, Int32) -> Int32 = { context, left, right, length in
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guard let context, let left else { return 0 }
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let source = Unmanaged<CallbackSource>.fromOpaque(context).takeUnretainedValue()
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var leftSpan = UnsafeMutableBufferPointer(start: left, count: Int(length)).mutableSpan
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var rightSpan = UnsafeMutableBufferPointer(start: right, count: right == nil ? 0 : Int(length)).mutableSpan
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return source.callback(&leftSpan, &rightSpan) ? 1 : 0
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}
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/// Attaches the C object created for this source.
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func adopt(pointer: OpaquePointer) {
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self.pointer = pointer
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CallbackSource.live.append(self)
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}
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}
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}
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