Add C++ and Python API for FireRedASR AED models (#1867)

sherpa-onnx/csrc/offline-fire-red-asr-decoder.h

@@ -0,0 +1,39 @@
+// sherpa-onnx/csrc/offline-fire-red-asr-decoder.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_
+
+#include <cstdint>
+#include <vector>
+
+#include "onnxruntime_cxx_api.h"  // NOLINT
+
+namespace sherpa_onnx {
+
+struct OfflineFireRedAsrDecoderResult {
+  /// The decoded token IDs
+  std::vector<int32_t> tokens;
+};
+
+class OfflineFireRedAsrDecoder {
+ public:
+  virtual ~OfflineFireRedAsrDecoder() = default;
+
+  /** Run beam search given the output from the FireRedAsr encoder model.
+   *
+   * @param n_layer_cross_k       A 4-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   * @param n_layer_cross_v       A 4-D tensor of shape
+   *                              (num_decoder_layers, N, T, d_model).
+   *
+   * @return Return a vector of size `N` containing the decoded results.
+   */
+  virtual std::vector<OfflineFireRedAsrDecoderResult> Decode(
+      Ort::Value n_layer_cross_k, Ort::Value n_layer_cross_v) = 0;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_FIRE_RED_ASR_DECODER_H_