generator: add strtolowerpls method

a convenience method, transforms strings to lowercase

generator.cpp

@@ -86,6 +86,11 @@ auto Generator::generate_random_data(uint n) -> string {
 };
 
 
+auto Generator::strtolowerpls(std::string &s) -> std::string {
+	std::transform(s.begin(),s.end(),s.begin(),::tolower);
+	return s;
+}
+
 } // namespace generator
 } // namespace fortuna
 #endif

generator.h

@@ -25,6 +25,8 @@ private:
 	/* n is the number of random bytes to generate */
 	auto generate_random_data(uint n) -> string;
 
+	auto strtolowerpls(string &s) -> string;
+
 protected:
 	auto get_state() -> Generator::G_state;