Add RNN LM rescore for offline ASR with modified_beam_search (#125)

sherpa-onnx/csrc/offline-lm-config.cc

@@ -0,0 +1,38 @@
+// sherpa-onnx/csrc/offline-lm-config.cc
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/offline-lm-config.h"
+
+#include <string>
+
+#include "sherpa-onnx/csrc/file-utils.h"
+#include "sherpa-onnx/csrc/macros.h"
+
+namespace sherpa_onnx {
+
+void OfflineLMConfig::Register(ParseOptions *po) {
+  po->Register("lm", &model, "Path to LM model.");
+  po->Register("lm-scale", &scale, "LM scale.");
+}
+
+bool OfflineLMConfig::Validate() const {
+  if (!FileExists(model)) {
+    SHERPA_ONNX_LOGE("%s does not exist", model.c_str());
+    return false;
+  }
+
+  return true;
+}
+
+std::string OfflineLMConfig::ToString() const {
+  std::ostringstream os;
+
+  os << "OfflineLMConfig(";
+  os << "model=\"" << model << "\", ";
+  os << "scale=" << scale << ")";
+
+  return os.str();
+}
+
+}  // namespace sherpa_onnx