initial commit

LibWhisper/WhisperStream.swift

@@ -0,0 +1,98 @@
+import AVFoundation
+
+public struct Segment {
+    let text: String
+    let t0: Int64
+    let t1: Int64
+}
+
+public typealias OrderedSegments = [Segment]
+
+public extension OrderedSegments {
+    var text: any StringProtocol {
+        map { $0.text }.joined()
+    }
+}
+
+public class WhisperStream: Thread {
+    let waiter = DispatchGroup()
+    
+    @Published public private(set) var segments = OrderedSegments()
+    @Published public private(set) var alive = true
+    
+    let model: URL
+    let device: CaptureDevice?
+    let window: TimeInterval
+    
+    public init(model: URL, device: CaptureDevice? = nil, window: TimeInterval = 300) {
+        self.model = model
+        self.device = device
+        self.window = window
+        super.init()
+    }
+    
+    public override func start() {
+        waiter.enter()
+        super.start()
+    }
+    
+    public override func main() {
+        task()
+        waiter.leave()
+    }
+    
+    public func join() {
+        waiter.wait()
+    }
+    
+    func task() {
+        model.path.withCString { modelCStr in
+            var params = stream_default_params()
+            params.model = modelCStr
+            
+            if let device = device {
+                params.capture_id = device.id
+            }
+            
+            let ctx = stream_init(params)
+            if ctx == nil {
+                return
+            }
+            
+            while !self.isCancelled {
+                let errno = stream_run(ctx, Unmanaged.passUnretained(self).toOpaque()) {
+                    return Unmanaged<WhisperStream>.fromOpaque($3!).takeUnretainedValue().callback(
+                        text: $0 != nil ? String(cString: $0!) : nil,
+                        t0: $1,
+                        t1: $2
+                    )
+                }
+                if errno != 0 {
+                    break
+                }
+            }
+            
+            stream_free(ctx)
+            alive = false
+        }
+    }
+    
+    func callback(text: String?, t0: Int64, t1: Int64) -> Int32 {
+        if segments.isEmpty || text == nil {
+            segments.append(Segment(text: "", t0: -1, t1: -1))
+        }
+        if let text = text {
+            segments[segments.count - 1] = Segment(text: text, t0: t0, t1: t1)
+        }
+        
+        var k = 0
+        for segment in segments {
+            if let last = segments.last, last.t0 - segment.t0 > Int64(window * 1000) {
+                k += 1
+            }
+        }
+        segments.removeFirst(k)
+        
+        return 0
+    }
+}