Refactor the code (#15)

* code refactoring

* Remove reference files

* Update README and CI

* small fixes

* fix style issues

* add style check for CI

* fix style issues

* remove kaldi-native-io

sherpa-onnx/csrc/wave-reader.cc

@@ -0,0 +1,108 @@
+/**
+ * Copyright      2022  Xiaomi Corporation (authors: Fangjun Kuang)
+ *
+ * See LICENSE for clarification regarding multiple authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sherpa-onnx/csrc/wave-reader.h"
+
+#include <cassert>
+#include <fstream>
+#include <iostream>
+#include <utility>
+#include <vector>
+
+namespace sherpa_onnx {
+
+namespace {
+// see http://soundfile.sapp.org/doc/WaveFormat/
+//
+// Note: We assume little endian here
+// TODO(fangjun): Support big endian
+struct WaveHeader {
+  void Validate() const {
+    //                       F F I R
+    assert(chunk_id == 0x46464952);
+    assert(chunk_size == 36 + subchunk2_size);
+    //                     E V A W
+    assert(format == 0x45564157);
+    assert(subchunk1_id == 0x20746d66);
+    assert(subchunk1_size == 16);  // 16 for PCM
+    assert(audio_format == 1);     // 1 for PCM
+    assert(num_channels == 1);     // we support only single channel for now
+    assert(byte_rate == sample_rate * num_channels * bits_per_sample / 8);
+    assert(block_align == num_channels * bits_per_sample / 8);
+    assert(bits_per_sample == 16);  // we support only 16 bits per sample
+  }
+
+  int32_t chunk_id;
+  int32_t chunk_size;
+  int32_t format;
+  int32_t subchunk1_id;
+  int32_t subchunk1_size;
+  int16_t audio_format;
+  int16_t num_channels;
+  int32_t sample_rate;
+  int32_t byte_rate;
+  int16_t block_align;
+  int16_t bits_per_sample;
+  int32_t subchunk2_id;
+  int32_t subchunk2_size;
+};
+static_assert(sizeof(WaveHeader) == 44, "");
+
+// Read a wave file of mono-channel.
+// Return its samples normalized to the range [-1, 1).
+std::vector<float> ReadWaveImpl(std::istream &is, float *sample_rate) {
+  WaveHeader header;
+  is.read(reinterpret_cast<char *>(&header), sizeof(header));
+  assert(static_cast<bool>(is));
+
+  header.Validate();
+
+  *sample_rate = header.sample_rate;
+
+  // header.subchunk2_size contains the number of bytes in the data.
+  // As we assume each sample contains two bytes, so it is divided by 2 here
+  std::vector<int16_t> samples(header.subchunk2_size / 2);
+
+  is.read(reinterpret_cast<char *>(samples.data()), header.subchunk2_size);
+
+  assert(static_cast<bool>(is));
+
+  std::vector<float> ans(samples.size());
+  for (int32_t i = 0; i != ans.size(); ++i) {
+    ans[i] = samples[i] / 32768.;
+  }
+
+  return ans;
+}
+
+}  // namespace
+
+std::vector<float> ReadWave(const std::string &filename,
+                            float expected_sample_rate) {
+  std::ifstream is(filename, std::ifstream::binary);
+  float sample_rate;
+  auto samples = ReadWaveImpl(is, &sample_rate);
+  if (expected_sample_rate != sample_rate) {
+    std::cerr << "Expected sample rate: " << expected_sample_rate
+              << ". Given: " << sample_rate << ".\n";
+    exit(-1);
+  }
+  return samples;
+}
+
+}  // namespace sherpa_onnx