Add C++ runtime for non-streaming faster conformer transducer from NeMo. (#854)

sherpa-onnx/csrc/symbol-table.h

@@ -40,14 +40,16 @@ class SymbolTable {
   int32_t operator[](const std::string &sym) const;
 
   /// Return true if there is a symbol with the given ID.
-  bool contains(int32_t id) const;
+  bool Contains(int32_t id) const;
 
   /// Return true if there is a given symbol in the symbol table.
-  bool contains(const std::string &sym) const;
+  bool Contains(const std::string &sym) const;
 
   // for tokens.txt from Whisper
   void ApplyBase64Decode();
 
+  int32_t NumSymbols() const { return id2sym_.size(); }
+
  private:
   void Init(std::istream &is);