going to change symbol table structure

include/utils.hpp

@@ -0,0 +1,36 @@
+#include <endian.h>
+#include <vector>
+#include <unordered_map>
+
+namespace utils {
+
+using IdType = std::size_t;
+
+template<typename T>
+class Storage {
+public:
+  IdType GetId(const T& value) {
+    IdType id = 0;
+    auto value_position = value_to_id_.find(value);
+
+    if (value_position == value_to_id_.end()) {
+      id = id_to_value_.size();
+      value_to_id_[value] = id;
+      id_to_value_.push_back(value);
+    } else {
+      id = value_position->second;
+    }
+
+    return id;
+  }
+
+  const T& GetValue(IdType id) {
+    return id_to_value_[id];
+  }
+
+private:
+  std::vector<T> id_to_value_;
+  std::unordered_map<T, IdType> value_to_id_;
+};
+
+} // namespace utils