pass str ref as parameter

src/lib.rs

@@ -163,7 +163,7 @@ impl Level {
         Ok(Self { size, player, map })
     }
 
-    fn read_rle(map: String) -> std::result::Result<Self, ReadError> {
+    fn read_rle(map: &str) -> std::result::Result<Self, ReadError> {
         let mut n: usize = 1;
 
         Self::read(
@@ -534,7 +534,7 @@ pub fn run(config: Config, rle: Option<String>) -> Result<()> {
     }
 
     let map = if let Some(rle) = rle {
-        Level::read_rle(rle)
+        Level::read_rle(&rle)
     } else {
         Level::read(std::io::stdin().lock())
     }