Refactor online recognizer (#250)

* Refactor online recognizer.

Make it easier to support other streaming models.

Note that it is a breaking change for the Python API.
`sherpa_onnx.OnlineRecognizer()` used before should be
replaced by `sherpa_onnx.OnlineRecognizer.from_transducer()`.

sherpa-onnx/python/csrc/online-model-config.cc

@@ -0,0 +1,35 @@
+// sherpa-onnx/python/csrc/online-model-config.cc
+//
+// Copyright (c)  2023 by manyeyes
+
+#include "sherpa-onnx/python/csrc/online-model-config.h"
+
+#include <string>
+#include <vector>
+
+#include "sherpa-onnx/csrc/online-model-config.h"
+#include "sherpa-onnx/csrc/online-transducer-model-config.h"
+#include "sherpa-onnx/python/csrc/online-transducer-model-config.h"
+
+namespace sherpa_onnx {
+
+void PybindOnlineModelConfig(py::module *m) {
+  PybindOnlineTransducerModelConfig(m);
+
+  using PyClass = OnlineModelConfig;
+  py::class_<PyClass>(*m, "OnlineModelConfig")
+      .def(py::init<const OnlineTransducerModelConfig &, std::string &, int32_t,
+                    bool, const std::string &, const std::string &>(),
+           py::arg("transducer") = OnlineTransducerModelConfig(),
+           py::arg("tokens"), py::arg("num_threads"), py::arg("debug") = false,
+           py::arg("provider") = "cpu", py::arg("model_type") = "")
+      .def_readwrite("transducer", &PyClass::transducer)
+      .def_readwrite("tokens", &PyClass::tokens)
+      .def_readwrite("num_threads", &PyClass::num_threads)
+      .def_readwrite("debug", &PyClass::debug)
+      .def_readwrite("provider", &PyClass::provider)
+      .def_readwrite("model_type", &PyClass::model_type)
+      .def("__str__", &PyClass::ToString);
+}
+
+}  // namespace sherpa_onnx