perf: improve performance

Sources/FluidAudio/ASR/Paraformer/ParaformerCif.swift

@@ -12,13 +12,20 @@ enum ParaformerCif {
     ///   - encRows: encoder output rows `[T][D]` (real frames only).
     ///   - alphas: per-frame weights `[T]` from the CifAlphas model.
     /// - Returns: acoustic embeddings `[L][D]`.
-    static func integrateAndFire(encRows: [[Float]], alphas: [Float]) -> [[Float]] {
+    /// CIF integrate-and-fire that also records the encoder-frame index at which
+    /// each acoustic token "fires" (the CIF boundary). The returned `fireFrames`
+    /// is the Swift port of FunASR's `pre_peak_index` and is consumed by the
+    /// timestamp routine (`ts_prediction_lfr6_standard`) to map tokens to time.
+    static func integrateAndFireWithFireFrames(
+        encRows: [[Float]], alphas: [Float]
+    ) -> (embeds: [[Float]], fireFrames: [Int]) {
         let threshold = ParaformerConfig.cifThreshold
         let tail = ParaformerConfig.cifTailThreshold
         let T = encRows.count
         let dim = encRows.first?.count ?? ParaformerConfig.encoderDim
 
         var embeds: [[Float]] = []
+        var fireFrames: [Int] = []
         var integrate: Float = 0
         var frame = [Float](repeating: 0, count: dim)
 
@@ -33,11 +40,17 @@ enum ParaformerCif {
                 let used = alpha - (integrate - threshold)  // portion to reach threshold
                 for d in 0..<dim { frame[d] += used * hidden[d] }
                 embeds.append(frame)
+                fireFrames.append(t)
                 integrate -= threshold
                 let leftover = alpha - used
                 frame = hidden.map { $0 * leftover }  // leftover seeds next token
             }
         }
-        return embeds
+        return (embeds, fireFrames)
+    }
+
+    /// Original integrate-and-fire entry point (embeds only).
+    static func integrateAndFire(encRows: [[Float]], alphas: [Float]) -> [[Float]] {
+        integrateAndFireWithFireFrames(encRows: encRows, alphas: alphas).embeds
     }
 }