Add non-streaming ASR (#92)

sherpa-onnx/csrc/offline-stream.h

@@ -0,0 +1,70 @@
+// sherpa-onnx/csrc/offline-stream.h
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_
+#define SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "sherpa-onnx/csrc/parse-options.h"
+
+namespace sherpa_onnx {
+struct OfflineRecognitionResult;
+
+struct OfflineFeatureExtractorConfig {
+  // Sampling rate used by the feature extractor. If it is different from
+  // the sampling rate of the input waveform, we will do resampling inside.
+  int32_t sampling_rate = 16000;
+
+  // Feature dimension
+  int32_t feature_dim = 80;
+
+  std::string ToString() const;
+
+  void Register(ParseOptions *po);
+};
+
+class OfflineStream {
+ public:
+  explicit OfflineStream(const OfflineFeatureExtractorConfig &config = {});
+  ~OfflineStream();
+
+  /**
+     @param sampling_rate The sampling_rate of the input waveform. If it does
+                          not equal to  config.sampling_rate, we will do
+                          resampling inside.
+     @param waveform Pointer to a 1-D array of size n. It must be normalized to
+                     the range [-1, 1].
+     @param n Number of entries in waveform
+
+     Caution: You can only invoke this function once so you have to input
+              all the samples at once
+   */
+  void AcceptWaveform(int32_t sampling_rate, const float *waveform,
+                      int32_t n) const;
+
+  /// Return feature dim of this extractor
+  int32_t FeatureDim() const;
+
+  // Get all the feature frames of this stream in a 1-D array, which is
+  // flattened from a 2-D array of shape (num_frames, feat_dim).
+  std::vector<float> GetFrames() const;
+
+  /** Set the recognition result for this stream. */
+  void SetResult(const OfflineRecognitionResult &r);
+
+  /** Get the recognition result of this stream */
+  const OfflineRecognitionResult &GetResult() const;
+
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_OFFLINE_STREAM_H_