diff --git a/src/main.cc b/src/main.cc
index eb72a9d..21066d6 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -362,13 +362,13 @@ int main() {
 //    printf("%09lX\n", CommonCode::from_string("1a9bf0c").unwrap());
 //    std::cout << CommonCode("4feA134") << std::endl;
 
-//    std::vector<uint64_t> all_cases;
-//    for (uint64_t head = 0; head < 16; ++head) {
-//        for (const auto &range : AllCases::fetch()[head]) {
-//            all_cases.emplace_back(head << 32 | range);
-//        }
-//    }
-//    std::cout << "test size: " << all_cases.size() << std::endl;
+    std::vector<uint64_t> all_cases;
+    for (uint64_t head = 0; head < 16; ++head) {
+        for (const auto &range : AllCases::fetch()[head]) {
+            all_cases.emplace_back(head << 32 | range);
+        }
+    }
+    std::cout << "test size: " << all_cases.size() << std::endl;
 
 //    for (const auto &common_code : all_cases) {
 //        if (RawCode::compact(RawCode::extract(common_code)) != common_code) {
@@ -380,7 +380,14 @@ int main() {
 
 //    std::cout << CommonCode(0x4FEA13400).to_raw_code().to_common_code() << std::endl;
 
-    std::cout << RawCode::check(CommonCode(0x4FEA13400).to_raw_code().unwrap()) << std::endl;
+//    std::cout << RawCode::check(CommonCode(0x4FEA13400).to_raw_code().unwrap()) << std::endl;
+
+    for (const auto &common_code : all_cases) {
+        if (!RawCode::check(RawCode::extract(common_code))) {
+            std::cout << "Error: " << CommonCode(common_code) << std::endl;
+        }
+    }
+
 
 //    std::cerr << (clock() - start_time) * 1000 / CLOCKS_PER_SEC << "ms" << std::endl;
     std::cerr << (clock() - start_time) * 1000000 / CLOCKS_PER_SEC << "us" << std::endl;
diff --git a/src/raw_code/raw_code.cc b/src/raw_code/raw_code.cc
index 4a62031..dfb8b99 100644
--- a/src/raw_code/raw_code.cc
+++ b/src/raw_code/raw_code.cc
@@ -6,89 +6,58 @@ uint64_t RawCode::unwrap() const { // get raw uint64_t code
     return code;
 }
 
-#include <iostream>
-
-/// we can check any raw_code in this function
-bool RawCode::check(uint64_t raw_code) {
+std::string RawCode::dump_case() const {
+    // TODO: using stack char *
+    std::string result;
+    result.reserve(40); // 5 lines * ("x x x x\n")
+    char dump_map[] = {
+    /// 0x0  1x2  2x1  1x1  2x2  b101 b110 fill
+        '.', '~', '|', '*', '@', '?', '?', '+'
+    };
+    auto raw_code = code;
+    for (int addr = 0; addr < 20; ++addr, raw_code >>= 3) {
+        result.push_back(dump_map[raw_code & 0b111]);
+        if ((addr & 0b11) == 0b11) {
+            result.push_back('\n'); // new line
+        } else {
+            result.push_back(' '); // add space
+        }
+    }
+    return result;
+}
 
+bool RawCode::check(uint64_t raw_code) { // check whether raw code is valid
     if (raw_code >> 60) {
         return false; // high 4-bits must be zero
     }
-
-    int head_num = 0;
-    int space_num = 0;
-
+    int head_num = 0, space_num = 0; // statistics for space and 2x2 number
     for (int addr = 0; addr < 20; ++addr, raw_code >>= 3) {
-
-//        std::cout << "addr = " << addr << " | block = " << (raw_code & 0b111) << std::endl;
-
         switch (raw_code & 0b111) {
+            case B_1x1:
+            case B_fill:
+                continue; // do nothing
             case B_space:
                 ++space_num;
-                break;
-            case B_1x1:
-                /// do nothing
-                break;
-            case B_1x2:
-
-                if ((addr & 0b11) == 0b11 || (raw_code & F_1x2) != C_1x2) {
-                    return false;
-                }
-
-                break;
+                continue;
             case B_2x1:
-
                 if (addr > 15 || (raw_code & F_2x1) != C_2x1) {
-                    return false;
+                    return false; // invalid 2x1 block
                 }
-
-                break;
+                continue;
+            case B_1x2:
+                if ((addr & 0b11) == 0b11 || (raw_code & F_1x2) != C_1x2) {
+                    return false; // invalid 1x2 block
+                }
+                continue;
             case B_2x2:
                 ++head_num;
-
                 if (addr > 14 || (addr & 0b11) == 0b11 || (raw_code & F_2x2) != C_2x2) {
-                    return false;
+                    return false; // invalid 2x2 block
                 }
-
-                break;
-
-            case B_fill:
-                /// do nothing
-                break;
-
+                continue;
             default:
-                return false; // unknown flag
+                return false; // unknown flag -> 0b101 / 0b110
         }
-
     }
-
-    // TODO: one 2x2 / >=2 space
-
-    // TODO: check head_num and space_num
-
-    if (head_num != 1 || space_num < 2) {
-        return false;
-    }
-
-    return true;
-}
-
-std::string RawCode::dump_case() const {
-    std::string result;
-    result.reserve(40); // 5 lines * ("x x x x\n")
-    char dump_map[] = {
-    /// 0x0  1x2  2x1  1x1  2x2  b101 b110 fill
-        '.', '~', '|', '*', '@', '?', '?', '+'
-    };
-
-    auto raw_code = code;
-    for (int addr = 0; addr < 20; ++addr, raw_code >>= 3) {
-        result.push_back(dump_map[raw_code & 0b111]);
-        if ((addr & 0b11) == 0b11) {
-            result.push_back('\n'); // new line
-        } else {
-            result.push_back(' '); // add space
-        }
-    }
-    return result;
+    return head_num == 1 && space_num >= 2; // one head and at least 2 space
 }
diff --git a/src/raw_code/raw_code.h b/src/raw_code/raw_code.h
index e7a2084..7a75c4e 100644
--- a/src/raw_code/raw_code.h
+++ b/src/raw_code/raw_code.h
@@ -29,9 +29,12 @@ public:
 
     // TODO: unsafe_create static function
 
+    static uint64_t compact(uint64_t raw_code);
+    static uint64_t extract(uint64_t common_code);
+
 private:
     uint64_t code;
 
-    static uint64_t compact(uint64_t raw_code);
-    static uint64_t extract(uint64_t common_code);
+//    static uint64_t compact(uint64_t raw_code);
+//    static uint64_t extract(uint64_t common_code);
 };