Support zipformer CTC ASR with whisper features. (#2319)

sherpa-onnx/csrc/online-stream.cc

@@ -19,34 +19,51 @@ class OnlineStream::Impl {
       : feat_extractor_(config), context_graph_(std::move(context_graph)) {}
 
   void AcceptWaveform(int32_t sampling_rate, const float *waveform, int32_t n) {
+    std::lock_guard<std::mutex> lock(mutex_);
     feat_extractor_.AcceptWaveform(sampling_rate, waveform, n);
   }
 
-  void InputFinished() const { feat_extractor_.InputFinished(); }
+  void InputFinished() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    feat_extractor_.InputFinished();
+  }
 
   int32_t NumFramesReady() const {
+    std::lock_guard<std::mutex> lock(mutex_);
     return feat_extractor_.NumFramesReady() - start_frame_index_;
   }
 
   bool IsLastFrame(int32_t frame) const {
+    std::lock_guard<std::mutex> lock(mutex_);
     return feat_extractor_.IsLastFrame(frame);
   }
 
   std::vector<float> GetFrames(int32_t frame_index, int32_t n) const {
+    std::lock_guard<std::mutex> lock(mutex_);
     return feat_extractor_.GetFrames(frame_index + start_frame_index_, n);
   }
 
   void Reset() {
+    std::lock_guard<std::mutex> lock(mutex_);
     // we don't reset the feature extractor
     start_frame_index_ += num_processed_frames_;
     num_processed_frames_ = 0;
   }
 
-  int32_t &GetNumProcessedFrames() { return num_processed_frames_; }
+  int32_t &GetNumProcessedFrames() {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return num_processed_frames_;
+  }
 
-  int32_t GetNumFramesSinceStart() const { return start_frame_index_; }
+  int32_t GetNumFramesSinceStart() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return start_frame_index_;
+  }
 
-  int32_t &GetCurrentSegment() { return segment_; }
+  int32_t &GetCurrentSegment() {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return segment_;
+  }
 
   void SetResult(const OnlineTransducerDecoderResult &r) { result_ = r; }
 
@@ -125,6 +142,7 @@ class OnlineStream::Impl {
 
  private:
   FeatureExtractor feat_extractor_;
+  mutable std::mutex mutex_;
   /// For contextual-biasing
   ContextGraphPtr context_graph_;
   int32_t num_processed_frames_ = 0;  // before subsampling