Add C++ API for streaming zipformer ASR on RK NPU (#1908)

sherpa-onnx/csrc/rknn/online-stream-rknn.h

@@ -0,0 +1,38 @@
+// sherpa-onnx/csrc/rknn/online-stream-rknn.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+#ifndef SHERPA_ONNX_CSRC_RKNN_ONLINE_STREAM_RKNN_H_
+#define SHERPA_ONNX_CSRC_RKNN_ONLINE_STREAM_RKNN_H_
+#include <memory>
+#include <vector>
+
+#include "rknn_api.h"  // NOLINT
+#include "sherpa-onnx/csrc/online-stream.h"
+#include "sherpa-onnx/csrc/rknn/online-transducer-greedy-search-decoder-rknn.h"
+
+namespace sherpa_onnx {
+
+class OnlineStreamRknn : public OnlineStream {
+ public:
+  explicit OnlineStreamRknn(const FeatureExtractorConfig &config = {},
+                            ContextGraphPtr context_graph = nullptr);
+
+  ~OnlineStreamRknn();
+
+  void SetZipformerEncoderStates(
+      std::vector<std::vector<uint8_t>> states) const;
+
+  std::vector<std::vector<uint8_t>> &GetZipformerEncoderStates() const;
+
+  void SetZipformerResult(OnlineTransducerDecoderResultRknn r) const;
+
+  OnlineTransducerDecoderResultRknn &GetZipformerResult() const;
+
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_RKNN_ONLINE_STREAM_RKNN_H_