diff --git a/src/main.cc b/src/main.cc
index 2daea28..13654c7 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -105,10 +105,17 @@ int main() {
 //    std::cout << ShortCode("EP4HZ", ShortCode::NORMAL).unwrap() << std::endl;
 //    std::cout << ShortCode("eP4hZ", ShortCode::FAST).to_string() << std::endl;
 
-//    std::cout << ShortCode::tiny_encode(0x6EC0F8800) << std::endl;
-//    printf("%09lX\n", ShortCode::tiny_decode(14323231));
 
-    std::cout << ShortCode(14323231).to_common_code().to_string() << std::endl;
+//    ShortCode::speed_up(ShortCode::FAST);
+//    std::cout << ShortCode(14323231).to_common_code().to_string() << std::endl;
+//    std::cout << ShortCode(CommonCode(0x6EC0F8800)).to_string() << std::endl;
+//
+////    ShortCode::speed_up(ShortCode::FAST);
+//    std::cout << ShortCode(14323231).to_common_code().to_string() << std::endl;
+//    std::cout << ShortCode(CommonCode(0x6EC0F8800)).to_string() << std::endl;
+
+    std::cout << ShortCode(CommonCode(0x6EC0F8800), ShortCode::NORMAL).to_string() << std::endl;
+    std::cout << ShortCode(CommonCode(0x6EC0F8800), ShortCode::FAST).to_string() << std::endl;
 
     return 0;
 }
diff --git a/src/short_code/convert.cc b/src/short_code/convert.cc
index dce2c26..9f1cdfb 100644
--- a/src/short_code/convert.cc
+++ b/src/short_code/convert.cc
@@ -10,6 +10,14 @@ CommonCode ShortCode::to_common_code() const { // convert to common code
     return CommonCode(all_cases_list[code]); // using fast mode
 }
 
+ShortCode::ShortCode(const CommonCode &common_code) { // convert from common code
+    if (ShortCode::check_mode() == ShortCode::NORMAL) {
+        code = tiny_encode(common_code.unwrap()); // using normal mode
+    } else {
+        code = all_cases_dict[common_code.unwrap()]; // using fast mode
+    }
+}
+
 /// ensure that input common code is valid
 uint32_t ShortCode::tiny_encode(uint64_t common_code) { // common_code --low-memory--> short_code
     uint32_t offset = 0;
diff --git a/src/short_code/short_code.h b/src/short_code/short_code.h
index 3372030..f40c5ec 100644
--- a/src/short_code/short_code.h
+++ b/src/short_code/short_code.h
@@ -11,24 +11,27 @@ public:
     enum Mode {
         NORMAL, FAST
     };
+    static enum Mode check_mode();
+    static void speed_up(enum Mode mode);
+
     uint32_t unwrap() const;
     std::string to_string() const;
     CommonCode to_common_code() const;
     static bool check(uint32_t short_code);
 
-    static enum Mode check_mode();
-    static void speed_up(enum Mode mode);
-
     explicit ShortCode(uint32_t short_code);
+    explicit ShortCode(const CommonCode &common_code);
     explicit ShortCode(const std::string &short_code_str);
     ShortCode(uint32_t short_code, enum Mode mode) : ShortCode(short_code) {
         speed_up(mode);
     }
+    ShortCode(const CommonCode &common_code, enum Mode mode) : ShortCode(common_code) {
+        speed_up(mode);
+    }
     ShortCode(const std::string &short_code_str, enum Mode mode) : ShortCode(short_code_str) {
         speed_up(mode);
     }
 
-
 private:
     uint32_t code;
     static std::mutex map_building;