Added this wad.rs thingy

It'll hopefully let me get into more rust AND doom stuff

src/wad.rs

@@ -0,0 +1,32 @@
+use std::path::PathBuf;
+use std::fs::File;
+use std::io::BufReader;
+use bincode;
+use serde::Deserialize;
+
+#[derive(Deserialize, Debug)]
+pub struct WadHeader {
+    pub identifier: [u8; 4],
+    pub num_lumps: i32,
+    pub file_offset_to_start: i32,
+}
+
+pub fn open_wad(path: &PathBuf) -> WadHeader {
+    let mut file =  BufReader::new(File::open(path).unwrap());
+    let header: WadHeader = bincode::deserialize_from(&mut file).unwrap();
+
+
+    header
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_open_wad() {
+        let freedoom_iwad = PathBuf::from("freedoom1.wad");
+        let ow = open_wad(&freedoom_iwad);
+        assert_eq!(std::str::from_utf8(&ow.identifier).unwrap(), "IWAD");
+    }
+}