diff --git a/README.md b/README.md
index ff45216cef233604d7a437462402e3618e3a9fcd..725b3742f0042e0e7527cdcbbbe8f727571c57c7 100644
--- a/README.md
+++ b/README.md
@@ -37,18 +37,18 @@ LevelDB for rust
 1. 1.0.0 版本, 完成 util 相关的内容
 
 
-| 功能模块                          | 完成人          |
-|-------------------------------|--------------|
-| Arena (Memory Management)     | wangboo      |
-| Slice                         | wangboo      |
-| BloomFilter                   | colagy       |
-| Cache                         | colagy       |
-| Coding (Primitive Type SerDe) | colagy       |
-| Comparator                    | fengyang     |
-| Status                        | fengyang     |
-| Random                        | fengyang     |
-| CRC                           | lxd5866      |
-| Env                           | lxd5866      |
-| Hash                          | lxd5866      |
-| MutexLock                     | kazeseiriou  |
-| Histgram                      | kazeseiriou  |
\ No newline at end of file
+| 功能模块                          | 完成人         |
+|-------------------------------|-------------|
+| Arena (Memory Management)     | wangboo     |
+| Slice                         | wangboo     |
+| Random                        | colagy      |
+| Cache                         | colagy      |
+| Coding (Primitive Type SerDe) | colagy      |
+| Comparator                    | fengyang    |
+| Status                        | fengyang    |
+| BloomFilter                   | fengyang    |
+| CRC                           | lxd5866     |
+| Env                           | lxd5866     |
+| Hash                          | lxd5866     |
+| MutexLock                     | kazeseiriou |
+| Histgram                      | kazeseiriou |
\ No newline at end of file
diff --git a/src/traits/iterator.rs b/src/traits/iterator.rs
index 319650a7a237f22507e4ef62f6347fac70f37f12..a985e81ad68b49c971c249bca5fefd5ae1908854 100644
--- a/src/traits/iterator.rs
+++ b/src/traits/iterator.rs
@@ -1,7 +1,6 @@
-use crate::util::Slice;
+use crate::util::slice::Slice;
 
 pub trait Iterator {
-
     fn valid(&self) -> bool;
 
     fn seek_to_first(&mut self);
@@ -19,6 +18,4 @@ pub trait Iterator {
     fn value(&self) -> &Slice;
 }
 
-trait AAA {
-
-}
+trait AAA {}
diff --git a/src/traits/mod.rs b/src/traits/mod.rs
index fb4a7b14ad387496c2539be1c2670821968f4824..74f6e800347c1bb0251c7f5bbabbba7ddd13c936 100644
--- a/src/traits/mod.rs
+++ b/src/traits/mod.rs
@@ -1,4 +1,4 @@
-use crate::util::Slice;
+use crate::util::slice::Slice;
 
 mod iterator;
 mod comparator;
diff --git a/src/util/coding.rs b/src/util/coding.rs
new file mode 100644
index 0000000000000000000000000000000000000000..74f2492e3cef4de6067d84fabb54e2da55413728
--- /dev/null
+++ b/src/util/coding.rs
@@ -0,0 +1,47 @@
+const B: u8 = 128;
+
+///
+///
+///
+pub trait Coding {
+    fn varint32(self, buf: &mut [u8]);
+}
+
+impl Coding for u32
+{
+    fn varint32(self, buf: &mut [u8]) {
+        // if self < 1 << 7 {
+        //     buf[0] = self as u8;
+        // } else if self < 1 << 14 {
+        //     buf[0] = self | B;
+        //     println!("{:b}", buf[0]);
+        //     buf[1] = buf[0] >> 7;
+        //     println!("{:b}", buf[1]);
+        // } else if self < 1 << 21 {
+        //     buf[0] = (self | B as u8) as u8;
+        //     println!("{:b}", buf[0]);
+        //     buf[1] = (buf[0] >> 7) | B;
+        //     println!("{:b}", buf[1]);
+        //     buf[2] = buf[1] >> 14;
+        //     println!("{:b}", buf[2]);
+        // } else if self < 1 << 28 {
+        //     buf[0] = (self | B as u8) as u8;
+        //     println!("{:b}", buf[0]);
+        //     buf[1] = (buf[0] >> 7) | B;
+        //     println!("{:b}", buf[1]);
+        //     buf[2] = (buf[1] >> 14) | B;
+        //     println!("{:b}", buf[2]);
+        //     buf[3] = buf[2] >> 21;
+        // } else {
+        //     buf[0] = (self | B as u8) as u8;
+        //     println!("{:b}", buf[0]);
+        //     buf[1] = (buf[0] >> 7) | B;
+        //     println!("{:b}", buf[1]);
+        //     buf[2] = (buf[1] >> 14) | B;
+        //     println!("{:b}", buf[2]);
+        //     buf[3] = (buf[2] >> 21) | B;
+        //     println!("{:b}", buf[3]);
+        //     buf[4] = buf[3] >> 28;
+        // }
+    }
+}
\ No newline at end of file
diff --git a/src/util/coding_test.rs b/src/util/coding_test.rs
new file mode 100644
index 0000000000000000000000000000000000000000..3c4184f62558e28f92d57534635ed78c81c3fc5c
--- /dev/null
+++ b/src/util/coding_test.rs
@@ -0,0 +1,20 @@
+mod test {
+    use crate::util::coding::Coding;
+
+    #[test]
+    fn test_i32() {
+        let mut buf: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0];
+        let x = 127.varint32(&mut buf);
+        println!("{:?}", buf);
+        println!("{:?}", x);
+        println!("{:b}", buf[0]);
+    }
+
+    #[test]
+    fn test_offset() {
+        let buf: [u8; 3] = [0, 1, 2];
+        let mut offset: usize = 0;
+        offset += 1;
+        println!("{:?}", buf[offset])
+    }
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 3f159e66e099d362139eb5513fe2506f8eab5d8b..fe7c884251c3c2b51d0c269ad6bcae918f4b8908 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -1,3 +1,5 @@
-mod slice;
-mod status;
-mod slice_test;
\ No newline at end of file
+pub mod slice;
+pub mod status;
+mod slice_test;
+pub mod coding;
+mod coding_test;
\ No newline at end of file