Optimize parameter passing to avoid unnecessary copying

src/files/files.hpp

@@ -20,7 +20,7 @@ namespace files {
         std::ifstream file;
         size_t filelength;
     public:
-        rafile(fs::path filename);
+        rafile(const fs::path& filename);
 
         void seekg(std::streampos pos);
         void read(char* buffer, std::streamsize size);
@@ -31,40 +31,40 @@ namespace files {
     /// @param file target file
     /// @param data data bytes array
     /// @param size size of data bytes array
-    bool write_bytes(fs::path file, const ubyte* data, size_t size);
+    bool write_bytes(const fs::path& file, const ubyte* data, size_t size);
 
     /// @brief Append bytes array to the file without any extra data
     /// @param file target file
     /// @param data data bytes array
     /// @param size size of data bytes array
-    uint append_bytes(fs::path file, const ubyte* data, size_t size);
+    uint append_bytes(const fs::path& file, const ubyte* data, size_t size);
 
     /// @brief Write string to the file
-    bool write_string(fs::path filename, const std::string content);
+    bool write_string(const fs::path& filename, const std::string content);
 
     /// @brief Write dynamic data to the JSON file
     /// @param nice if true, human readable format will be used, otherwise minimal
-    bool write_json(fs::path filename, const dynamic::Map* obj, bool nice=true);
+    bool write_json(const fs::path& filename, const dynamic::Map* obj, bool nice=true);
 
     /// @brief Write dynamic data to the binary JSON file
     /// (see src/coders/binary_json_spec.md)
     /// @param compressed use gzip compression
     bool write_binary_json(
-        fs::path filename, 
+        const fs::path& filename,
         const dynamic::Map* obj, 
         bool compressed=false
     );
 
-    bool read(fs::path, char* data, size_t size);
-    std::unique_ptr<ubyte[]> read_bytes(fs::path, size_t& length);
-    std::string read_string(fs::path filename);
+    bool read(const fs::path&, char* data, size_t size);
+    std::unique_ptr<ubyte[]> read_bytes(const fs::path&, size_t& length);
+    std::string read_string(const fs::path& filename);
 
     /// @brief Read JSON or BJSON file
     /// @param file *.json or *.bjson file
-    std::shared_ptr<dynamic::Map> read_json(fs::path file);
-    std::shared_ptr<dynamic::Map> read_binary_json(fs::path file);
-    std::shared_ptr<dynamic::Map> read_toml(fs::path file);
-    std::vector<std::string> read_list(fs::path file);
+    std::shared_ptr<dynamic::Map> read_json(const fs::path& file);
+    std::shared_ptr<dynamic::Map> read_binary_json(const fs::path& file);
+    std::shared_ptr<dynamic::Map> read_toml(const fs::path& file);
+    std::vector<std::string> read_list(const fs::path& file);
 }
 
 #endif /* FILES_FILES_HPP_ */