diff --git a/src/core/benchmark/codec.cc b/src/core/benchmark/codec.cc
index c769783..847acb6 100644
--- a/src/core/benchmark/codec.cc
+++ b/src/core/benchmark/codec.cc
@@ -18,7 +18,7 @@ using klotski::codec::CommonCode;
 static std::vector<uint64_t> all_common_codes() {
     std::vector<uint64_t> codes;
     for (uint64_t head = 0; head < 16; ++head) {
-        for (const auto range : AllCases::instance().fetch()[head]) {
+        for (const auto range : AllCases::instance().fetch().ranges(head)) {
             codes.emplace_back(head << 32 | range);
         }
     }
diff --git a/src/core/benchmark/group.cc b/src/core/benchmark/group.cc
index a7529e0..28f48d1 100644
--- a/src/core/benchmark/group.cc
+++ b/src/core/benchmark/group.cc
@@ -26,7 +26,7 @@ using klotski::codec::CommonCode;
 static std::vector<uint64_t> all_common_codes() {
     std::vector<uint64_t> codes;
     for (uint64_t head = 0; head < 16; ++head) {
-        for (const auto range : AllCases::instance().fetch()[head]) {
+        for (const auto range : AllCases::instance().fetch().ranges(head)) {
             codes.emplace_back(head << 32 | range);
         }
     }
@@ -342,7 +342,7 @@ static void FastObtainCode(benchmark::State &state) {
     size_t offset = 0;
     for (int i = 0; i < 16; ++i) {
         sizes[i] = offset;
-        offset += data[i].size();
+        offset += data.ranges(i).size();
     }
 
     std::vector infos {
@@ -376,14 +376,14 @@ static void FastObtainCode(benchmark::State &state) {
             uint64_t head = 0;
             auto case_id = info.case_id();
             for (;;) {
-                if (case_id >= cases[head].size()) {
-                    case_id -= cases[head].size();
+                if (case_id >= cases.ranges(head).size()) {
+                    case_id -= cases.ranges(head).size();
                     ++head;
                 } else {
                     break;
                 }
             }
-            auto range = cases[head][case_id];
+            auto range = cases.ranges(head)[case_id];
             volatile auto kk = CommonCode::unsafe_create(head << 32 | range);
 
             /// about 117ns
diff --git a/src/core_ffi/CMakeLists.txt b/src/core_ffi/CMakeLists.txt
index 36cdeab..3583740 100644
--- a/src/core_ffi/CMakeLists.txt
+++ b/src/core_ffi/CMakeLists.txt
@@ -19,13 +19,13 @@ if (KLSK_RUST_FFI)
     install(TARGETS klotski_core DESTINATION .)
   else()
     # just for IDE highlight
-    add_library(klotski_rust
+    add_library(klotski_rs
       rust_ffi/adapter/short_code.cc
       rust_ffi/adapter/common_code.cc
       rust_ffi/target/cxxbridge/rust_ffi/src/bridge.rs.cc
     )
-    target_include_directories(klotski_rust PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
-    target_include_directories(klotski_rust PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/rust_ffi/target/cxxbridge)
-    target_link_libraries(klotski_rust PRIVATE klotski_core)
+    target_include_directories(klotski_rs PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+    target_include_directories(klotski_rs PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/rust_ffi/target/cxxbridge)
+    target_link_libraries(klotski_rs PRIVATE klotski_core)
   endif()
 endif()
diff --git a/src/core_ffi/c_ffi/all_cases.cc b/src/core_ffi/c_ffi/all_cases.cc
index c9ded49..b338b18 100644
--- a/src/core_ffi/c_ffi/all_cases.cc
+++ b/src/core_ffi/c_ffi/all_cases.cc
@@ -64,7 +64,7 @@ const uint32_t* all_cases_export(const int head) {
     if (all_cases_num(head) < 0) {
         return nullptr;
     }
-    return AllCases::instance().fetch()[head].data();
+    return AllCases::instance().fetch().ranges(head).data();
 }
 
 // ------------------------------------------------------------------------------------- //
diff --git a/src/core_test/helper/internal/parallel.cc b/src/core_test/helper/internal/parallel.cc
index 6e56731..665c398 100644
--- a/src/core_test/helper/internal/parallel.cc
+++ b/src/core_test/helper/internal/parallel.cc
@@ -44,7 +44,7 @@ void helper::common_code_parallel(std::function<void(std::span<CommonCode>)> &&f
 
     // TODO: enhance performance
 
-    pool.detach_blocks((uint64_t)0, codes.size(), [&func](auto start, auto end) {
+    pool.detach_blocks((size_t)0, codes.size(), [&func](auto start, auto end) {
 
         func(std::span<CommonCode> {codes.data() + start, end - start});
 
@@ -60,7 +60,7 @@ void helper::raw_code_parallel(std::function<void(std::span<RawCode>)> &&func) {
     static auto codes = std::vector<RawCode> {common_codes.begin(), common_codes.end()};
 
     BS::thread_pool pool;
-    pool.detach_blocks((uint64_t)0, codes.size(), [&func](auto start, auto end) {
+    pool.detach_blocks((size_t)0, codes.size(), [&func](auto start, auto end) {
 
         func(std::span<RawCode> {codes.data() + start, end - start});
 
@@ -78,7 +78,7 @@ void helper::short_code_parallel(std::function<void(std::span<ShortCode>)> &&fun
     }();
 
     BS::thread_pool pool;
-    pool.detach_blocks((uint64_t)0, codes.size(), [&func](auto start, auto end) {
+    pool.detach_blocks((size_t)0, codes.size(), [&func](auto start, auto end) {
 
         auto span = std::span<uint32_t> {codes.data() + start, end - start};
         func(std::bit_cast<std::span<ShortCode>>(span));