Fix style issues (#1458)

sherpa-onnx/csrc/offline-ctc-fst-decoder.cc

@@ -11,52 +11,11 @@
 #include "kaldi-decoder/csrc/decodable-ctc.h"
 #include "kaldi-decoder/csrc/eigen.h"
 #include "kaldi-decoder/csrc/faster-decoder.h"
+#include "sherpa-onnx/csrc/fst-utils.h"
 #include "sherpa-onnx/csrc/macros.h"
 
 namespace sherpa_onnx {
 
-// This function is copied from kaldi.
-//
-// @param filename Path to a StdVectorFst or StdConstFst graph
-// @return The caller should free the returned pointer using `delete` to
-//         avoid memory leak.
-fst::Fst<fst::StdArc> *ReadGraph(const std::string &filename) {
-  // read decoding network FST
-  std::ifstream is(filename, std::ios::binary);
-  if (!is.good()) {
-    SHERPA_ONNX_LOGE("Could not open decoding-graph FST %s", filename.c_str());
-  }
-
-  fst::FstHeader hdr;
-  if (!hdr.Read(is, "<unknown>")) {
-    SHERPA_ONNX_LOGE("Reading FST: error reading FST header.");
-  }
-
-  if (hdr.ArcType() != fst::StdArc::Type()) {
-    SHERPA_ONNX_LOGE("FST with arc type %s not supported",
-                     hdr.ArcType().c_str());
-  }
-  fst::FstReadOptions ropts("<unspecified>", &hdr);
-
-  fst::Fst<fst::StdArc> *decode_fst = nullptr;
-
-  if (hdr.FstType() == "vector") {
-    decode_fst = fst::VectorFst<fst::StdArc>::Read(is, ropts);
-  } else if (hdr.FstType() == "const") {
-    decode_fst = fst::ConstFst<fst::StdArc>::Read(is, ropts);
-  } else {
-    SHERPA_ONNX_LOGE("Reading FST: unsupported FST type: %s",
-                     hdr.FstType().c_str());
-  }
-
-  if (decode_fst == nullptr) {  // fst code will warn.
-    SHERPA_ONNX_LOGE("Error reading FST (after reading header).");
-    return nullptr;
-  } else {
-    return decode_fst;
-  }
-}
-
 /**
  * @param decoder
  * @param p Pointer to a 2-d array of shape (num_frames, vocab_size)