diff --git a/src/main.rs b/src/main.rs
index 30843e4..4e25371 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,29 +1,65 @@
-use std::{fs, io::{self, BufRead, BufReader}};
+use std::{fs, io::{self, BufRead, BufReader, Write}, fmt::format};
 
 fn main() {
-
-    println!("Hello, world!");
+    let args : Vec<String> = std::env::args().collect();
+    if args.len() < 3 {
+        println!("usage: {} <patch_file> <patch_code>", args[0]);
+        return;
+    }
+    let codes = match read_codes(args[2].as_str()) {
+        Ok(code) => code,
+        Err(e) => {
+            println!("read code error: {}", e.to_string());
+            return;
+        }
+    };
+    if let Err(e) = apply_code(args[1].as_str(), &codes) {
+        println!("apply code error: {}", e.to_string());
+    }
 }
 
-fn read_codes(code_file : &str) ->  io::Result<Vec<u32>> {
-    let file = fs::File::open(code_file)?;
+fn read_codes(code_file : &str) -> io::Result<Vec<(u32, u32)>> {
+    let file = fs::File::open(code_file).expect("cannot open patch_code");
     let reader = BufReader::new(file);
     let mut codes = Vec::new();
-    let mut line_count = 0;
+    let mut lines = 0u32;
     for line in reader.lines() {
         if let Ok(l) = line {
             let r_str = l.as_str();
             let code_vec : Vec<&str> = r_str.split(' ').collect();
             if code_vec.len() == 2 {
-                let val1 : u32 = code_vec[0].parse().unwrap_or_default();
-                let val2 : u32 = code_vec[1].parse().unwrap_or_default();
-                codes.push(val1);
-                codes.push(val2);
-            } else {
-                println!("code error at line {}.", line_count);
-            }
+                let val1 = u32::from_str_radix(code_vec[0], 16);
+                let val2 = u32::from_str_radix(code_vec[1], 16);
+                if val1.is_ok() && val2.is_ok() {
+                    codes.push((lines, val1.unwrap()));
+                    codes.push((lines, val2.unwrap()));
+                }
+            } // else skip
         }
-        line_count += 1;
     }
     Ok(codes)
 }
+
+fn verify_code(codes : Vec<(u32, u32)>) -> Result<(), String> {
+    let pos = 0usize;
+    while pos < codes.len() {
+        let first_code = codes[pos].1;
+        let op_code = first_code >> 28;
+        let mut search_code = false;
+        match op_code {
+            0x0 | 0x1 |0x2 => {
+                return Err(format!("{}", 123));
+            }
+            _ => (),
+        }
+        pos += 1;
+    }
+    Ok(())
+}
+
+fn apply_code(patch_file : &str, codes : &Vec<(u32, u32)>) -> io::Result<()> {
+    let data = fs::read(patch_file)?;
+    let mut write_file = fs::OpenOptions::new().write(true).truncate(true).open(patch_file)?;
+    write_file.write(data.as_slice())?;
+    Ok(())
+}