diff --git a/src/klotski_core/ffi/tmain.cc b/src/klotski_core/ffi/tmain.cc
index 180ea9f..004c9bb 100644
--- a/src/klotski_core/ffi/tmain.cc
+++ b/src/klotski_core/ffi/tmain.cc
@@ -21,9 +21,14 @@ void tmain() {
 //    std::cout << ret.to_common_code() << std::endl << ret << std::endl;
 
 //    klotski::RawCode::from_common_code(0x1A9BF0C00).is_vertical_mirror();
-    auto ret = klotski::RawCode::from_common_code(0x1A9BF0C00).to_vertical_mirror();
+//    auto ret = klotski::RawCode::from_common_code(0x1A9BF0C00).to_vertical_mirror();
+//
+//    std::cout << ret.to_common_code() << std::endl << ret << std::endl;
 
-    std::cout << ret.to_common_code() << std::endl << ret << std::endl;
+//    std::cout << klotski::RawCode::from_common_code(0x4FEA13400) << std::endl;
+//    std::cout << klotski::RawCode::from_common_code(0x8346AFC00) << std::endl;
+//    std::cout << klotski::RawCode::from_common_code(0x1A9BF0C00) << std::endl;
+    std::cout << klotski::RawCode::from_common_code(0x6BFA47000) << std::endl;
 
     return;
 
diff --git a/src/rust_ffi/src/codec/ffi.rs b/src/rust_ffi/src/codec/ffi.rs
index 4a99a26..a154712 100644
--- a/src/rust_ffi/src/codec/ffi.rs
+++ b/src/rust_ffi/src/codec/ffi.rs
@@ -50,7 +50,8 @@ pub fn common_code_check(common_code: u64) -> bool {
     }
 }
 
-fn raw_code_to_short_code(raw_code: u64) -> Result<u32, &'static str> {
+#[allow(dead_code)]
+pub fn raw_code_to_short_code(raw_code: u64) -> Result<u32, &'static str> {
     let mut short_code: u32 = 0;
     unsafe {
         match Core::raw_code_to_short_code(raw_code, &mut short_code) {
@@ -60,7 +61,8 @@ fn raw_code_to_short_code(raw_code: u64) -> Result<u32, &'static str> {
     }
 }
 
-fn short_code_to_raw_code(short_code: u32) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn short_code_to_raw_code(short_code: u32) -> Result<u64, &'static str> {
     let mut raw_code: u64 = 0;
     unsafe {
         match Core::short_code_to_raw_code(short_code, &mut raw_code) {
@@ -70,7 +72,8 @@ fn short_code_to_raw_code(short_code: u32) -> Result<u64, &'static str> {
     }
 }
 
-fn raw_code_to_common_code(raw_code: u64) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn raw_code_to_common_code(raw_code: u64) -> Result<u64, &'static str> {
     let mut common_code: u64 = 0;
     unsafe {
         match Core::raw_code_to_common_code(raw_code, &mut common_code) {
@@ -80,7 +83,8 @@ fn raw_code_to_common_code(raw_code: u64) -> Result<u64, &'static str> {
     }
 }
 
-fn common_code_to_raw_code(common_code: u64) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn common_code_to_raw_code(common_code: u64) -> Result<u64, &'static str> {
     let mut raw_code: u64 = 0;
     unsafe {
         match Core::common_code_to_raw_code(common_code, &mut raw_code) {
@@ -90,7 +94,8 @@ fn common_code_to_raw_code(common_code: u64) -> Result<u64, &'static str> {
     }
 }
 
-fn short_code_to_common_code(short_code: u32) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn short_code_to_common_code(short_code: u32) -> Result<u64, &'static str> {
     let mut common_code: u64 = 0;
     unsafe {
         match Core::short_code_to_common_code(short_code, &mut common_code) {
@@ -100,7 +105,8 @@ fn short_code_to_common_code(short_code: u32) -> Result<u64, &'static str> {
     }
 }
 
-fn common_code_to_short_code(common_code: u64) -> Result<u32, &'static str> {
+#[allow(dead_code)]
+pub fn common_code_to_short_code(common_code: u64) -> Result<u32, &'static str> {
     let mut short_code: u32 = 0;
     unsafe {
         match Core::common_code_to_short_code(common_code, &mut short_code) {
@@ -110,43 +116,50 @@ fn common_code_to_short_code(common_code: u64) -> Result<u32, &'static str> {
     }
 }
 
-fn raw_code_to_short_code_unsafe(raw_code: u64) -> u32 {
+#[allow(dead_code)]
+pub fn raw_code_to_short_code_unsafe(raw_code: u64) -> u32 {
     unsafe {
         Core::raw_code_to_short_code_unsafe(raw_code)
     }
 }
 
-fn short_code_to_raw_code_unsafe(short_code: u32) -> u64 {
+#[allow(dead_code)]
+pub fn short_code_to_raw_code_unsafe(short_code: u32) -> u64 {
     unsafe {
         Core::short_code_to_raw_code_unsafe(short_code)
     }
 }
 
-fn raw_code_to_common_code_unsafe(raw_code: u64) -> u64 {
+#[allow(dead_code)]
+pub fn raw_code_to_common_code_unsafe(raw_code: u64) -> u64 {
     unsafe {
         Core::raw_code_to_common_code_unsafe(raw_code)
     }
 }
 
-fn common_code_to_raw_code_unsafe(common_code: u64) -> u64 {
+#[allow(dead_code)]
+pub fn common_code_to_raw_code_unsafe(common_code: u64) -> u64 {
     unsafe {
         Core::common_code_to_raw_code_unsafe(common_code)
     }
 }
 
-fn short_code_to_common_code_unsafe(short_code: u32) -> u64 {
+#[allow(dead_code)]
+pub fn short_code_to_common_code_unsafe(short_code: u32) -> u64 {
     unsafe {
         Core::short_code_to_common_code_unsafe(short_code)
     }
 }
 
-fn common_code_to_short_code_unsafe(common_code: u64) -> u32 {
+#[allow(dead_code)]
+pub fn common_code_to_short_code_unsafe(common_code: u64) -> u32 {
     unsafe {
         Core::common_code_to_short_code_unsafe(common_code)
     }
 }
 
-fn is_vertical_mirror(raw_code: u64) -> Result<bool, &'static str> {
+#[allow(dead_code)]
+pub fn is_vertical_mirror(raw_code: u64) -> Result<bool, &'static str> {
     let mut result: bool = false;
     unsafe {
         match Core::is_vertical_mirror(raw_code, &mut result) {
@@ -156,7 +169,8 @@ fn is_vertical_mirror(raw_code: u64) -> Result<bool, &'static str> {
     }
 }
 
-fn is_horizontal_mirror(raw_code: u64) -> Result<bool, &'static str> {
+#[allow(dead_code)]
+pub fn is_horizontal_mirror(raw_code: u64) -> Result<bool, &'static str> {
     let mut result: bool = false;
     unsafe {
         match Core::is_horizontal_mirror(raw_code, &mut result) {
@@ -166,7 +180,8 @@ fn is_horizontal_mirror(raw_code: u64) -> Result<bool, &'static str> {
     }
 }
 
-fn to_vertical_mirror(raw_code: u64) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn to_vertical_mirror(raw_code: u64) -> Result<u64, &'static str> {
     let mut result: u64 = 0;
     unsafe {
         match Core::to_vertical_mirror(raw_code, &mut result) {
@@ -176,7 +191,8 @@ fn to_vertical_mirror(raw_code: u64) -> Result<u64, &'static str> {
     }
 }
 
-fn to_horizontal_mirror(raw_code: u64) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn to_horizontal_mirror(raw_code: u64) -> Result<u64, &'static str> {
     let mut result: u64 = 0;
     unsafe {
         match Core::to_horizontal_mirror(raw_code, &mut result) {
@@ -186,31 +202,36 @@ fn to_horizontal_mirror(raw_code: u64) -> Result<u64, &'static str> {
     }
 }
 
-fn is_vertical_mirror_unsafe(raw_code: u64) -> bool {
+#[allow(dead_code)]
+pub fn is_vertical_mirror_unsafe(raw_code: u64) -> bool {
     unsafe {
         Core::is_vertical_mirror_unsafe(raw_code)
     }
 }
 
-fn is_horizontal_mirror_unsafe(raw_code: u64) -> bool {
+#[allow(dead_code)]
+pub fn is_horizontal_mirror_unsafe(raw_code: u64) -> bool {
     unsafe {
         Core::is_horizontal_mirror_unsafe(raw_code)
     }
 }
 
-fn to_vertical_mirror_unsafe(raw_code: u64) -> u64 {
+#[allow(dead_code)]
+pub fn to_vertical_mirror_unsafe(raw_code: u64) -> u64 {
     unsafe {
         Core::to_vertical_mirror_unsafe(raw_code)
     }
 }
 
-fn to_horizontal_mirror_unsafe(raw_code: u64) -> u64 {
+#[allow(dead_code)]
+pub fn to_horizontal_mirror_unsafe(raw_code: u64) -> u64 {
     unsafe {
         Core::to_horizontal_mirror_unsafe(raw_code)
     }
 }
 
-fn short_code_to_string(short_code: u32) -> Result<String, &'static str> {
+#[allow(dead_code)]
+pub fn short_code_to_string(short_code: u32) -> Result<String, &'static str> {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::SHORT_CODE_STR_SIZE as usize];
         match Core::short_code_to_string(short_code, buffer.as_mut_ptr()) {
@@ -226,7 +247,8 @@ fn short_code_to_string(short_code: u32) -> Result<String, &'static str> {
     }
 }
 
-fn short_code_to_string_unsafe(short_code: u32) -> String {
+#[allow(dead_code)]
+pub fn short_code_to_string_unsafe(short_code: u32) -> String {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::SHORT_CODE_STR_SIZE as usize];
         Core::short_code_to_string(short_code, buffer.as_mut_ptr());
@@ -238,7 +260,8 @@ fn short_code_to_string_unsafe(short_code: u32) -> String {
     }
 }
 
-fn short_code_from_string(short_code: &str) -> Result<u32, &'static str> {
+#[allow(dead_code)]
+pub fn short_code_from_string(short_code: &str) -> Result<u32, &'static str> {
     unsafe {
         let mut result: u32 = 0;
         match Core::short_code_from_string(
@@ -251,7 +274,8 @@ fn short_code_from_string(short_code: &str) -> Result<u32, &'static str> {
     }
 }
 
-fn common_code_to_string(common_code: u64) -> Result<String, &'static str> {
+#[allow(dead_code)]
+pub fn common_code_to_string(common_code: u64) -> Result<String, &'static str> {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::COMMON_CODE_STR_SIZE as usize];
         match Core::common_code_to_string(common_code, buffer.as_mut_ptr()) {
@@ -267,7 +291,8 @@ fn common_code_to_string(common_code: u64) -> Result<String, &'static str> {
     }
 }
 
-fn common_code_to_string_unsafe(common_code: u64) -> String {
+#[allow(dead_code)]
+pub fn common_code_to_string_unsafe(common_code: u64) -> String {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::COMMON_CODE_STR_SIZE as usize];
         Core::common_code_to_string_unsafe(common_code, buffer.as_mut_ptr());
@@ -279,7 +304,8 @@ fn common_code_to_string_unsafe(common_code: u64) -> String {
     }
 }
 
-fn common_code_to_string_shorten(common_code: u64) -> Result<String, &'static str> {
+#[allow(dead_code)]
+pub fn common_code_to_string_shorten(common_code: u64) -> Result<String, &'static str> {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::COMMON_CODE_STR_SIZE as usize];
         match Core::common_code_to_string_shorten(common_code, buffer.as_mut_ptr()) {
@@ -296,7 +322,8 @@ fn common_code_to_string_shorten(common_code: u64) -> Result<String, &'static st
     }
 }
 
-fn common_code_to_string_shorten_unsafe(common_code: u64) -> String {
+#[allow(dead_code)]
+pub fn common_code_to_string_shorten_unsafe(common_code: u64) -> String {
     unsafe {
         let mut buffer: Vec<c_char> = vec![0; Core::COMMON_CODE_STR_SIZE as usize];
         Core::common_code_to_string_shorten(common_code, buffer.as_mut_ptr());
@@ -309,7 +336,8 @@ fn common_code_to_string_shorten_unsafe(common_code: u64) -> String {
     }
 }
 
-fn common_code_from_string(common_code: &str) -> Result<u64, &'static str> {
+#[allow(dead_code)]
+pub fn common_code_from_string(common_code: &str) -> Result<u64, &'static str> {
     unsafe {
         let mut result: u64 = 0;
         match Core::common_code_from_string(
diff --git a/src/rust_ffi/src/codec/mod.rs b/src/rust_ffi/src/codec/mod.rs
index b92c889..733a2de 100644
--- a/src/rust_ffi/src/codec/mod.rs
+++ b/src/rust_ffi/src/codec/mod.rs
@@ -1,4 +1,4 @@
 mod ffi;
 mod tests;
 
-use super::core::Core;
+use crate::core::Core;
diff --git a/src/rust_ffi/src/codec/tests.rs b/src/rust_ffi/src/codec/tests.rs
index baa00b8..24b5db6 100644
--- a/src/rust_ffi/src/codec/tests.rs
+++ b/src/rust_ffi/src/codec/tests.rs
@@ -1,5 +1,6 @@
+#[cfg(test)]
 mod ffi {
-    #[allow(unused_imports)]
+    // #[allow(unused_imports)]
     use crate::codec::ffi as codec_ffi;
 
     #[test]
@@ -13,39 +14,28 @@ mod ffi {
         assert_eq!(codec_ffi::is_short_code_available_fast(), true);
     }
 
-    #[allow(dead_code)]
     const TEST_SHORT_CODE_OK: u32 = 4091296;
-
-    #[allow(dead_code)]
     const TEST_SHORT_CODE_STR_OK: &str = "4WVE1";
-
-    #[allow(dead_code)]
     const TEST_COMMON_CODE_OK: u64 = 0x1_A9BF_0C00;
-
-    #[allow(dead_code)]
     const TEST_COMMON_CODE_STR_OK: &str = "1A9BF0C00";
-
-    #[allow(dead_code)]
     const TEST_COMMON_CODE_STR_SHR_OK: &str = "1A9BF0C";
-
-    #[allow(dead_code)]
     const TEST_RAW_CODE_OK: u64 = 0x0603_EDF5_CAFF_F5E2;
 
-    #[allow(dead_code)]
     const TEST_SHORT_CODE_ERR: u32 = 29670987;
-
-    #[allow(dead_code)]
     const TEST_COMMON_CODE_ERR: u64 = 0x1_2190_2300;
-
-    #[allow(dead_code)]
     const TEST_RAW_CODE_ERR: u64 = 0x0A34_182B_3810_2D21;
 
-    #[allow(dead_code)]
     const TEST_SHORT_CODE_STR_ERR: &str = "R50EH";
-
-    #[allow(dead_code)]
     const TEST_COMMON_CODE_STR_ERR: &str = "123J432A9";
 
+    const TEST_MIRROR_V: u64 = 0x0_FC0_480_6DB_FC0_480;
+    const TEST_MIRROR_V1: u64 = 0x0_E58_FC8_5FF_EBC_4DB;
+    const TEST_MIRROR_V2: u64 = 0x0_EDB_5FF_EBC_5C8_E58;
+
+    const TEST_MIRROR_H: u64 = 0x0_603_EDF_5CA_FFF_5E2;
+    const TEST_MIRROR_H1: u64 = 0x0_E58_FC8_5FF_EBC_4DB;
+    const TEST_MIRROR_H2: u64 = 0x0_0F9_1CF_FFA_F17_6DA;
+
     #[test]
     fn checker() {
         assert_eq!(codec_ffi::raw_code_check(TEST_RAW_CODE_OK), true);
@@ -58,14 +48,258 @@ mod ffi {
         assert_eq!(codec_ffi::common_code_check(TEST_COMMON_CODE_ERR), false);
     }
 
+    #[test]
+    fn convert() {
+        // raw code -> short code
+        assert!(codec_ffi::raw_code_to_short_code(TEST_RAW_CODE_ERR).is_err());
+        assert!(codec_ffi::raw_code_to_short_code(TEST_RAW_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::raw_code_to_short_code(TEST_RAW_CODE_OK).unwrap(),
+            TEST_SHORT_CODE_OK
+        );
+
+        // short code -> raw code
+        assert!(codec_ffi::short_code_to_raw_code(TEST_SHORT_CODE_ERR).is_err());
+        assert!(codec_ffi::short_code_to_raw_code(TEST_SHORT_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::short_code_to_raw_code(TEST_SHORT_CODE_OK).unwrap(),
+            TEST_RAW_CODE_OK
+        );
+
+        // raw code -> common code
+        assert!(codec_ffi::raw_code_to_common_code(TEST_RAW_CODE_ERR).is_err());
+        assert!(codec_ffi::raw_code_to_common_code(TEST_RAW_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::raw_code_to_common_code(TEST_RAW_CODE_OK).unwrap(),
+            TEST_COMMON_CODE_OK
+        );
+
+        // common code -> raw code
+        assert!(codec_ffi::common_code_to_raw_code(TEST_COMMON_CODE_ERR).is_err());
+        assert!(codec_ffi::common_code_to_raw_code(TEST_COMMON_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::common_code_to_raw_code(TEST_COMMON_CODE_OK).unwrap(),
+            TEST_RAW_CODE_OK
+        );
+
+        // short code -> common code
+        assert!(codec_ffi::short_code_to_common_code(TEST_SHORT_CODE_ERR).is_err());
+        assert!(codec_ffi::short_code_to_common_code(TEST_SHORT_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::short_code_to_common_code(TEST_SHORT_CODE_OK).unwrap(),
+            TEST_COMMON_CODE_OK
+        );
+
+        // common code -> short code
+        assert!(codec_ffi::common_code_to_short_code(TEST_COMMON_CODE_ERR).is_err());
+        assert!(codec_ffi::common_code_to_short_code(TEST_COMMON_CODE_OK).is_ok());
+        assert_eq!(
+            codec_ffi::common_code_to_short_code(TEST_COMMON_CODE_OK).unwrap(),
+            TEST_SHORT_CODE_OK
+        );
+    }
+
+    #[test]
+    fn convert_unsafe() {
+        // raw code <---> short code
+        assert_eq!(
+            codec_ffi::raw_code_to_short_code_unsafe(TEST_RAW_CODE_OK),
+            TEST_SHORT_CODE_OK
+        );
+        assert_eq!(
+            codec_ffi::short_code_to_raw_code_unsafe(TEST_SHORT_CODE_OK),
+            TEST_RAW_CODE_OK
+        );
+
+        // raw code <---> common code
+        assert_eq!(
+            codec_ffi::raw_code_to_common_code_unsafe(TEST_RAW_CODE_OK),
+            TEST_COMMON_CODE_OK
+        );
+        assert_eq!(
+            codec_ffi::common_code_to_raw_code_unsafe(TEST_COMMON_CODE_OK),
+            TEST_RAW_CODE_OK
+        );
+
+        // short code <---> common code
+        assert_eq!(
+            codec_ffi::short_code_to_common_code_unsafe(TEST_SHORT_CODE_OK),
+            TEST_COMMON_CODE_OK
+        );
+        assert_eq!(
+            codec_ffi::common_code_to_short_code_unsafe(TEST_COMMON_CODE_OK),
+            TEST_SHORT_CODE_OK
+        );
+    }
+
+    #[test]
+    fn mirror() {
+        assert!(codec_ffi::is_vertical_mirror(TEST_RAW_CODE_ERR).is_err());
+        assert!(codec_ffi::is_horizontal_mirror(TEST_RAW_CODE_ERR).is_err());
+        assert!(codec_ffi::to_vertical_mirror(TEST_RAW_CODE_ERR).is_err());
+        assert!(codec_ffi::to_horizontal_mirror(TEST_RAW_CODE_ERR).is_err());
+
+        let tmp = codec_ffi::is_vertical_mirror(TEST_RAW_CODE_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), false);
+        let tmp = codec_ffi::is_vertical_mirror(TEST_MIRROR_V1);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), false);
+        let tmp = codec_ffi::is_vertical_mirror(TEST_MIRROR_V2);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), false);
+
+        let tmp = codec_ffi::to_vertical_mirror(TEST_MIRROR_V1);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_MIRROR_V2);
+        let tmp = codec_ffi::to_vertical_mirror(TEST_MIRROR_V2);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_MIRROR_V1);
+
+        let tmp = codec_ffi::is_horizontal_mirror(TEST_MIRROR_H);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), true);
+        let tmp = codec_ffi::is_horizontal_mirror(TEST_MIRROR_H1);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), false);
+        let tmp = codec_ffi::is_horizontal_mirror(TEST_MIRROR_H2);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), false);
+
+        let tmp = codec_ffi::to_horizontal_mirror(TEST_MIRROR_H);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_MIRROR_H);
+        let tmp = codec_ffi::to_horizontal_mirror(TEST_MIRROR_H1);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_MIRROR_H2);
+        let tmp = codec_ffi::to_horizontal_mirror(TEST_MIRROR_H2);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_MIRROR_H1);
+    }
+
+    #[test]
+    fn mirror_unsafe() {
+        assert!(codec_ffi::is_vertical_mirror_unsafe(TEST_MIRROR_V));
+        assert!(!codec_ffi::is_vertical_mirror_unsafe(TEST_MIRROR_V1));
+        assert!(!codec_ffi::is_vertical_mirror_unsafe(TEST_MIRROR_V2));
+
+        assert!(codec_ffi::is_horizontal_mirror_unsafe(TEST_MIRROR_H));
+        assert!(!codec_ffi::is_horizontal_mirror_unsafe(TEST_MIRROR_H1));
+        assert!(!codec_ffi::is_horizontal_mirror_unsafe(TEST_MIRROR_H2));
+
+        assert_eq!(
+            codec_ffi::to_vertical_mirror_unsafe(TEST_MIRROR_V),
+            TEST_MIRROR_V
+        );
+        assert_eq!(
+            codec_ffi::to_vertical_mirror_unsafe(TEST_MIRROR_V1),
+            TEST_MIRROR_V2
+        );
+        assert_eq!(
+            codec_ffi::to_vertical_mirror_unsafe(TEST_MIRROR_V2),
+            TEST_MIRROR_V1
+        );
+
+        assert_eq!(
+            codec_ffi::to_horizontal_mirror_unsafe(TEST_MIRROR_H),
+            TEST_MIRROR_H
+        );
+        assert_eq!(
+            codec_ffi::to_horizontal_mirror_unsafe(TEST_MIRROR_H1),
+            TEST_MIRROR_H2
+        );
+        assert_eq!(
+            codec_ffi::to_horizontal_mirror_unsafe(TEST_MIRROR_H2),
+            TEST_MIRROR_H1
+        );
+    }
+
     // TODO: string
 
-    // TODO: convert
+    // EXPECT_EQ(SHORT_CODE_STR_SIZE, 6);
+    // EXPECT_EQ(COMMON_CODE_STR_SIZE, 10);
+    //
+    // /// short code string verify
+    // uint32_t short_code;
+    // char short_code_buffer[SHORT_CODE_STR_SIZE];
+    // EXPECT_EQ(short_code_to_string(TEST_SHORT_CODE_ERR, short_code_buffer), false);
+    // EXPECT_EQ(short_code_from_string(TEST_SHORT_CODE_STR_ERR, &short_code), false);
+    //
+    // EXPECT_EQ(short_code_to_string(TEST_SHORT_CODE_OK, short_code_buffer), true);
+    // EXPECT_STREQ(short_code_buffer, TEST_SHORT_CODE_STR_OK);
+    // short_code_to_string_unsafe(TEST_SHORT_CODE_OK, short_code_buffer);
+    // EXPECT_STREQ(short_code_buffer, TEST_SHORT_CODE_STR_OK);
+    //
+    // EXPECT_EQ(short_code_from_string(TEST_SHORT_CODE_STR_OK, &short_code), true);
+    // EXPECT_EQ(short_code, TEST_SHORT_CODE_OK);
+    //
+    // /// common code string verify
+    // uint64_t common_code;
+    // char common_code_buffer[COMMON_CODE_STR_SIZE];
+    // EXPECT_EQ(common_code_to_string(TEST_COMMON_CODE_ERR, common_code_buffer), false);
+    // EXPECT_EQ(common_code_from_string(TEST_COMMON_CODE_STR_ERR, &common_code), false);
+    //
+    // EXPECT_EQ(common_code_to_string(TEST_COMMON_CODE_OK, common_code_buffer), true);
+    // EXPECT_STREQ(common_code_buffer, TEST_COMMON_CODE_STR_OK);
+    // common_code_to_string_unsafe(TEST_COMMON_CODE_OK, common_code_buffer);
+    // EXPECT_STREQ(common_code_buffer, TEST_COMMON_CODE_STR_OK);
+    //
+    // EXPECT_EQ(common_code_to_string_shorten(TEST_COMMON_CODE_OK, common_code_buffer), true);
+    // EXPECT_STREQ(common_code_buffer, TEST_COMMON_CODE_STR_SHR_OK);
+    // common_code_to_string_shorten_unsafe(TEST_COMMON_CODE_OK, common_code_buffer);
+    // EXPECT_STREQ(common_code_buffer, TEST_COMMON_CODE_STR_SHR_OK);
+    //
+    // EXPECT_EQ(common_code_from_string(TEST_COMMON_CODE_STR_OK, &common_code), true);
+    // EXPECT_EQ(common_code, TEST_COMMON_CODE_OK);
+    // EXPECT_EQ(common_code_from_string(TEST_COMMON_CODE_STR_SHR_OK, &common_code), true);
+    // EXPECT_EQ(common_code, TEST_COMMON_CODE_OK);
+
+    #[test]
+    fn string() {
+        // short code string
+        assert!(codec_ffi::short_code_to_string(TEST_SHORT_CODE_ERR).is_err());
+        assert!(codec_ffi::short_code_from_string(TEST_SHORT_CODE_STR_ERR).is_err());
 
-    // TODO: convert_unsafe
+        let tmp = codec_ffi::short_code_to_string(TEST_SHORT_CODE_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_SHORT_CODE_STR_OK);
+        assert_eq!(
+            codec_ffi::short_code_to_string_unsafe(TEST_SHORT_CODE_OK),
+            TEST_SHORT_CODE_STR_OK
+        );
 
-    // TODO: mirror
+        // common code string
+        assert!(
+            codec_ffi::common_code_to_string(TEST_COMMON_CODE_ERR).is_err()
+        );
+        assert!(
+            codec_ffi::common_code_to_string_shorten(TEST_COMMON_CODE_ERR).is_err()
+        );
+        assert!(
+            codec_ffi::common_code_from_string(TEST_COMMON_CODE_STR_ERR).is_err()
+        );
 
-    // TODO: mirror_unsafe
+        let tmp = codec_ffi::common_code_to_string(TEST_COMMON_CODE_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_COMMON_CODE_STR_OK);
+        assert_eq!(
+            codec_ffi::common_code_to_string_unsafe(TEST_COMMON_CODE_OK),
+            TEST_COMMON_CODE_STR_OK
+        );
 
+        let tmp = codec_ffi::common_code_to_string_shorten(TEST_COMMON_CODE_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_COMMON_CODE_STR_SHR_OK);
+        assert_eq!(
+            codec_ffi::common_code_to_string_shorten_unsafe(TEST_COMMON_CODE_OK),
+            TEST_COMMON_CODE_STR_SHR_OK
+        );
+
+        let tmp = codec_ffi::common_code_from_string(TEST_COMMON_CODE_STR_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_COMMON_CODE_OK);
+        let tmp = codec_ffi::common_code_from_string(TEST_COMMON_CODE_STR_SHR_OK);
+        assert!(tmp.is_ok());
+        assert_eq!(tmp.unwrap(), TEST_COMMON_CODE_OK);
+    }
 }
diff --git a/test/ffi/codec.cc b/test/ffi/codec.cc
index d5cb35c..ae5bd37 100644
--- a/test/ffi/codec.cc
+++ b/test/ffi/codec.cc
@@ -79,6 +79,7 @@ TEST(FFI, codec_string) {
     uint64_t common_code;
     char common_code_buffer[COMMON_CODE_STR_SIZE];
     EXPECT_EQ(common_code_to_string(TEST_COMMON_CODE_ERR, common_code_buffer), false);
+    EXPECT_EQ(common_code_to_string_shorten(TEST_COMMON_CODE_ERR, common_code_buffer), false);
     EXPECT_EQ(common_code_from_string(TEST_COMMON_CODE_STR_ERR, &common_code), false);
 
     EXPECT_EQ(common_code_to_string(TEST_COMMON_CODE_OK, common_code_buffer), true);
@@ -156,8 +157,14 @@ TEST(FFI, codec_mirror) {
     EXPECT_EQ(to_vertical_mirror(TEST_RAW_CODE_ERR, &raw_code), false);
     EXPECT_EQ(to_horizontal_mirror(TEST_RAW_CODE_ERR, &raw_code), false);
 
+    // function always return false
     EXPECT_EQ(is_vertical_mirror(TEST_RAW_CODE_OK, &result), true);
-    EXPECT_EQ(result, false); // function always return false
+    EXPECT_EQ(result, false);
+    EXPECT_EQ(is_vertical_mirror(TEST_MIRROR_V1, &result), true);
+    EXPECT_EQ(result, false);
+    EXPECT_EQ(is_vertical_mirror(TEST_MIRROR_V2, &result), true);
+    EXPECT_EQ(result, false);
+
     EXPECT_EQ(to_vertical_mirror(TEST_MIRROR_V1, &raw_code), true);
     EXPECT_EQ(raw_code, TEST_MIRROR_V2);
     EXPECT_EQ(to_vertical_mirror(TEST_MIRROR_V2, &raw_code), true);
@@ -169,6 +176,9 @@ TEST(FFI, codec_mirror) {
     EXPECT_EQ(result, false);
     EXPECT_EQ(is_horizontal_mirror(TEST_MIRROR_H2, &result), true);
     EXPECT_EQ(result, false);
+
+    EXPECT_EQ(to_horizontal_mirror(TEST_MIRROR_H, &raw_code), true);
+    EXPECT_EQ(raw_code, TEST_MIRROR_H);
     EXPECT_EQ(to_horizontal_mirror(TEST_MIRROR_H1, &raw_code), true);
     EXPECT_EQ(raw_code, TEST_MIRROR_H2);
     EXPECT_EQ(to_horizontal_mirror(TEST_MIRROR_H2, &raw_code), true);