magic number and impossible out of bound for tree and char

src/main.rs

@@ -10,6 +10,8 @@ mod node;
 use byte_writer::{binary_to_string, string_to_binary};
 use node::{Node, create_tree, read_tree, tree_to_map, tree_to_string};
 
+const MAGIC_NUMBER: u8 = 128;
+
 fn main() -> std::io::Result<()> {
     let args: Vec<String> = env::args().collect();
 
@@ -36,9 +38,9 @@ fn main() -> std::io::Result<()> {
                         let binary = string_to_binary(&str_bin);
                         let len_tree: u32 = str_bin.len() as u32;
                         let string: String = chars.iter().collect();
-                        after_compression
-                            .write_all(&(len_tree + (string.len() as u32) * 8).to_be_bytes())?;
+                        after_compression.write_all(&MAGIC_NUMBER.to_be_bytes())?;
                         after_compression.write_all(&len_tree.to_be_bytes())?;
+                        after_compression.write_all(&(string.len() as u32).to_be_bytes())?;
                         after_compression.write_all(&binary)?;
                         after_compression.write_all(string.as_bytes())?;
                         to_compress.seek(SeekFrom::Start(0))?;
@@ -59,9 +61,18 @@ fn main() -> std::io::Result<()> {
                 match file_name {
                     Some(f) => {
                         let mut to_print = File::open(f)?;
+                        let mut mag_buf = [0u8];
+                        let _ = to_print.read_exact(&mut mag_buf);
+                        match u8::from_be_bytes(mag_buf) {
+                            128 => {
                                 let untranslate = string_translate(&mut to_print);
                                 eprintln!("untranslate = {}", untranslate);
                             }
+                            _ => {
+                                println!("Error oppening file, check type file !")
+                            }
+                        }
+                    }
                     None => {
                         println!("No file name!");
                         display_options();
@@ -118,22 +129,16 @@ fn get_map_file(mut file: &File) -> Result<HashMap<char, i32>, std::io::Error> {
 fn string_translate(file: &mut File) -> String {
     let mut buffer = [0u8; 4];
     let _ = file.read_exact(&mut buffer);
-    let len_head = u32::from_be_bytes(buffer);
-    let _ = file.read_exact(&mut buffer);
     let len_tree = u32::from_be_bytes(buffer);
-    //eprintln!("len_head = {:?}", len_head);
-    //eprintln!("len_tree = {:?}", len_tree);
+    let _ = file.read_exact(&mut buffer);
+    let len_chars = u32::from_be_bytes(buffer) * 8;
 
-    let len_chars = len_head - len_tree;
     let tree_bin = read_n_bytes(file, len_tree);
     let tree_str = binary_to_string(tree_bin, len_tree);
-    //eprintln!("tree_str = {:?}", tree_str);
 
     let chars_bin = read_n_bytes(file, len_chars);
     let chars_str = String::from_utf8(chars_bin).unwrap();
     let root = read_tree(&tree_str, &chars_str.chars().collect());
-    //let map = tree_to_map(&mut root, true);
-    //eprintln!("map = {:?}", map);
     let _ = file.read_exact(&mut buffer);
     let len_body = u32::from_be_bytes(buffer);
     translate_bin_char(file, root, len_body)