Add C++ runtime and Python APIs for Moonshine models (#1473)

sherpa-onnx/csrc/offline-moonshine-decoder.h

@@ -0,0 +1,34 @@
+// sherpa-onnx/csrc/offline-moonshine-decoder.h
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_MOONSHINE_DECODER_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_MOONSHINE_DECODER_H_
+
+#include <vector>
+
+#include "onnxruntime_cxx_api.h"  // NOLINT
+
+namespace sherpa_onnx {
+
+struct OfflineMoonshineDecoderResult {
+  /// The decoded token IDs
+  std::vector<int32_t> tokens;
+};
+
+class OfflineMoonshineDecoder {
+ public:
+  virtual ~OfflineMoonshineDecoder() = default;
+
+  /** Run beam search given the output from the moonshine encoder model.
+   *
+   * @param encoder_out A 3-D tensor of shape (batch_size, T, dim)
+   * @return Return a vector of size `N` containing the decoded results.
+   */
+  virtual std::vector<OfflineMoonshineDecoderResult> Decode(
+      Ort::Value encoder_out) = 0;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_MOONSHINE_DECODER_H_