diff --git a/src/klotski/CMakeLists.txt b/src/klotski/CMakeLists.txt
index 32fe0b1..a7a2401 100644
--- a/src/klotski/CMakeLists.txt
+++ b/src/klotski/CMakeLists.txt
@@ -63,7 +63,7 @@ add_subdirectory(benchmark)
 
 ################################################################################
 
-set(FFI_SRC codec.cc all_cases.cc tmain.cc version.cc)
+set(FFI_SRC codec.cc all_cases.cc tmain.cc metadata.cc)
 list(TRANSFORM FFI_SRC PREPEND "ffi/")
 add_library(klotski-ffi OBJECT ${FFI_SRC})
 
diff --git a/src/klotski/ffi/all_cases.cc b/src/klotski/ffi/all_cases.cc
index 6f7b728..4bba079 100644
--- a/src/klotski/ffi/all_cases.cc
+++ b/src/klotski/ffi/all_cases.cc
@@ -3,8 +3,9 @@
 
 using klotski::AllCases;
 using klotski::BasicRanges;
-using klotski::BASIC_RANGES_SIZE;
-using klotski::ALL_CASES_SIZE_SUM;
+
+const uint32_t ALL_CASES_SIZE = klotski::ALL_CASES_SIZE_SUM;
+const uint32_t BASIC_RANGES_SIZE = klotski::BASIC_RANGES_SIZE;
 
 void all_cases_build() {
     AllCases::build();
@@ -21,3 +22,17 @@ bool is_all_cases_available() {
 bool is_basic_ranges_available() {
     return BasicRanges::status() == BasicRanges::AVAILABLE;
 }
+
+void export_all_cases(uint64_t *buffer) {
+    for (uint64_t head = 0; head < 16; ++head) {
+        for (const auto &range : AllCases::fetch()[head]) {
+            *(buffer++) = head << 32 | range;
+        }
+    }
+}
+
+void export_basic_ranges(uint32_t *buffer) {
+    for (const auto &range : BasicRanges::fetch()) {
+        *(buffer++) = range;
+    }
+}
diff --git a/src/klotski/ffi/codec.cc b/src/klotski/ffi/codec.cc
index 8606ef2..9a4a33e 100644
--- a/src/klotski/ffi/codec.cc
+++ b/src/klotski/ffi/codec.cc
@@ -106,7 +106,7 @@ bool common_code_to_short_code(uint64_t common_code, uint32_t *short_code) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-const uint32_t short_code_string_size = 6;
+const uint32_t SHORT_CODE_STR_SIZE = 6;
 
 bool short_code_to_string(uint32_t short_code, char short_code_str[]) {
     if (!ShortCode::check(short_code)) {
@@ -128,7 +128,7 @@ bool short_code_from_string(const char short_code_str[], uint32_t *short_code) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-const uint32_t common_code_string_size = 10;
+const uint32_t COMMON_CODE_STR_SIZE = 10;
 
 bool common_code_to_string(uint64_t common_code, char common_code_str[]) {
     if (!CommonCode::check(common_code)) {
diff --git a/src/klotski/ffi/klotski.h b/src/klotski/ffi/klotski.h
index 00a6058..72bec22 100644
--- a/src/klotski/ffi/klotski.h
+++ b/src/klotski/ffi/klotski.h
@@ -17,7 +17,7 @@ extern "C" {
 }
 #endif
 
-/// --------------------------------- klotski version info ----------------------------------
+/// -------------------------------- klotski metadata info ----------------------------------
 
 #ifdef __cplusplus
 extern "C" {
@@ -48,10 +48,10 @@ extern "C" {
     extern bool is_all_cases_available();
     extern bool is_basic_ranges_available();
 
-    extern const uint32_t all_cases_size;
+    extern const uint32_t ALL_CASES_SIZE;
     extern void export_all_cases(uint64_t *buffer);
 
-    extern const uint32_t basic_ranges_size;
+    extern const uint32_t BASIC_RANGES_SIZE;
     extern void export_basic_ranges(uint32_t *buffer);
 #ifdef __cplusplus
 }
@@ -80,12 +80,12 @@ extern "C" {
     extern bool common_code_to_short_code(uint64_t common_code, uint32_t *short_code);
 
     /// output char[] buffer at least 6-bytes
-    extern const uint32_t short_code_string_size;
+    extern const uint32_t SHORT_CODE_STR_SIZE;
     extern bool short_code_to_string(uint32_t short_code, char short_code_str[]);
     extern bool short_code_from_string(const char short_code_str[], uint32_t *short_code);
 
     /// output char[] buffer at least 10-bytes
-    extern const uint32_t common_code_string_size;
+    extern const uint32_t COMMON_CODE_STR_SIZE;
     extern bool common_code_to_string(uint64_t common_code, char common_code_str[]);
     extern bool common_code_to_string_shorten(uint64_t common_code, char common_code_str[]);
     extern bool common_code_from_string(const char common_code_str[], uint64_t *common_code);
diff --git a/src/klotski/ffi/version.cc b/src/klotski/ffi/metadata.cc
similarity index 100%
rename from src/klotski/ffi/version.cc
rename to src/klotski/ffi/metadata.cc
diff --git a/src/main.c b/src/main.c
index 19d4f6e..2fdcb46 100644
--- a/src/main.c
+++ b/src/main.c
@@ -29,7 +29,7 @@ int main() {
         printf("short code -> %d\n", short_code);
     }
 
-    char common_code_str[common_code_string_size];
+    char common_code_str[COMMON_CODE_STR_SIZE];
     if (!common_code_to_string(common_code, common_code_str)) {
         printf("error\n");
     } else {
@@ -46,7 +46,7 @@ int main() {
         printf("common code -> %09lX\n", common_code);
     }
 
-    char short_code_str[short_code_string_size];
+    char short_code_str[SHORT_CODE_STR_SIZE];
     if (!short_code_to_string(short_code, short_code_str)) {
         printf("error\n");
     } else {