diff --git a/src/common_code/common_code.cc b/src/common_code/common_code.cc
index e8b4be9..2772180 100644
--- a/src/common_code/common_code.cc
+++ b/src/common_code/common_code.cc
@@ -8,14 +8,20 @@ inline uint8_t last_zero_num(uint32_t bin) { // get last zero number
     return __builtin_popcount(bin >> 1);
 }
 
-uint64_t CommonCode::unwrap() const {
-    return code; // get raw uint64_t code
+uint64_t CommonCode::unwrap() const { // get raw uint64_t code
+    return code;
 }
 
 ShortCode CommonCode::to_short_code() const { // convert to short code
     return ShortCode(*this);
 }
 
+CommonCode CommonCode::unsafe_create(uint64_t code) { // create CommonCode without check
+    auto common_code = CommonCode(); // init directly
+    common_code.code = code;
+    return common_code;
+}
+
 CommonCode::CommonCode(uint64_t common_code) {
     if (!CommonCode::check(common_code)) { // check input common code
         throw std::invalid_argument("invalid common code");
@@ -23,6 +29,10 @@ CommonCode::CommonCode(uint64_t common_code) {
     code = common_code;
 }
 
+CommonCode::CommonCode(const ShortCode &short_code) {
+    code = short_code.to_common_code().unwrap(); // init from short code
+}
+
 CommonCode::CommonCode(const std::string &common_code_str) {
     if (common_code_str.length() > 9 || common_code_str.length() == 0) { // check string length
         throw std::invalid_argument("common code format error");
diff --git a/src/common_code/common_code.h b/src/common_code/common_code.h
index c8529d3..79d66d1 100644
--- a/src/common_code/common_code.h
+++ b/src/common_code/common_code.h
@@ -11,11 +11,14 @@ public:
     uint64_t unwrap() const;
     ShortCode to_short_code() const;
     static bool check(uint64_t common_code);
+    static CommonCode unsafe_create(uint64_t code);
     std::string to_string(bool shorten = false) const;
 
     explicit CommonCode(uint64_t common_code);
+    explicit CommonCode(const ShortCode &short_code);
     explicit CommonCode(const std::string &common_code_str);
 
 private:
     uint64_t code;
+    CommonCode() = default;
 };
diff --git a/src/main.cc b/src/main.cc
index ffd86b9..a91bd59 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -117,6 +117,12 @@ int main() {
 //    std::cout << ShortCode(CommonCode(0x6EC0F8800), ShortCode::NORMAL).to_string() << std::endl;
 //    std::cout << ShortCode(CommonCode(0x6EC0F8800), ShortCode::FAST).to_string() << std::endl;
 
+//    std::cout << CommonCode(0x6EC0F8800).to_short_code().to_string() << std::endl;
+
+    std::cout << CommonCode(ShortCode(14323231)).to_string() << std::endl;
+    std::cout << ShortCode(14323231).to_common_code().to_string() << std::endl;
+
+    std::cout << ShortCode(CommonCode(0x6EC0F8800)).to_string() << std::endl;
     std::cout << CommonCode(0x6EC0F8800).to_short_code().to_string() << std::endl;
 
     return 0;
diff --git a/src/short_code/convert.cc b/src/short_code/convert.cc
index 9f1cdfb..8a3420b 100644
--- a/src/short_code/convert.cc
+++ b/src/short_code/convert.cc
@@ -5,9 +5,9 @@
 
 CommonCode ShortCode::to_common_code() const { // convert to common code
     if (ShortCode::check_mode() == ShortCode::NORMAL) {
-        return CommonCode(tiny_decode(code)); // using normal mode
+        return CommonCode::unsafe_create(tiny_decode(code)); // using normal mode
     }
-    return CommonCode(all_cases_list[code]); // using fast mode
+    return CommonCode::unsafe_create(all_cases_list[code]); // using fast mode
 }
 
 ShortCode::ShortCode(const CommonCode &common_code) { // convert from common code
diff --git a/src/short_code/short_code.cc b/src/short_code/short_code.cc
index 9443665..43aad3e 100644
--- a/src/short_code/short_code.cc
+++ b/src/short_code/short_code.cc
@@ -2,8 +2,8 @@
 #include "short_code.h"
 #include "short_code_chars.h"
 
-uint32_t ShortCode::unwrap() const {
-    return code; // get raw uint32_t code
+uint32_t ShortCode::unwrap() const { // get raw uint32_t code
+    return code;
 }
 
 bool ShortCode::check(uint32_t short_code) {