feat: add benchmark of range reverse

src/core/CMakeLists.txt

@@ -57,3 +57,7 @@ target_link_libraries(bm_all_cases PRIVATE klotski::core benchmark::benchmark_ma
 add_executable(bm_ranges benchmark/ranges.cc)
 target_compile_options(bm_ranges PRIVATE -fno-rtti -fno-exceptions)
 target_link_libraries(bm_ranges PRIVATE klotski::core benchmark::benchmark_main)
+
+add_executable(bm_utility benchmark/utility.cc)
+target_compile_options(bm_utility PRIVATE -fno-rtti -fno-exceptions)
+target_link_libraries(bm_utility PRIVATE klotski::core benchmark::benchmark_main)

src/core/benchmark/utility.cc

@@ -0,0 +1,39 @@
+#include <benchmark/benchmark.h>
+
+#include <iostream>
+
+#include "utils/utility.h"
+#include "all_cases/all_cases.h"
+
+using klotski::cases::Ranges;
+using klotski::cases::BasicRanges;
+
+static Ranges range_samples() {
+    auto ranges = BasicRanges::instance().fetch();
+
+    Ranges samples;
+
+    for (uint64_t i = 0; i < ranges.size(); ++i) {
+        if (i % 73500 == 0) {
+            samples.emplace_back(ranges[i]);
+        }
+    }
+
+    return samples;
+}
+
+static void range_reverse(benchmark::State &state) {
+
+    auto samples = range_samples();
+
+    for (auto _ : state) {
+        for (const auto range : samples) {
+            volatile auto kk = klotski::range_reverse(range);
+        }
+    }
+
+}
+
+BENCHMARK(range_reverse);
+
+BENCHMARK_MAIN();

src/core/utils/utility.h

@@ -5,6 +5,8 @@
 #include <numeric>
 #include <functional>
 
+// ----------------------------------------------------------------------------------------- //
+
 /// Mark target class as a singleton.
 #define KLSK_INSTANCE(T)                  \
     private:                              \
@@ -28,6 +30,8 @@
 /// Prevent reordering for both compiler and processor.
 #define KLSK_MEM_BARRIER std::atomic_thread_fence(std::memory_order_seq_cst)
 
+// ----------------------------------------------------------------------------------------- //
+
 namespace klotski {
 
 /// Calculate the sum of an array of integers.
@@ -54,20 +58,14 @@ consteval std::array<T, N> to_offset(const std::array<T, N> &arr) {
 }
 
 /// Flips the input u32 every two bits in low-high symmetry.
-inline uint32_t range_reverse(uint32_t bin) {
+constexpr uint32_t range_reverse(uint32_t bin) {
     bin = std::byteswap(bin);
-// #if defined(__GNUC__) || defined(__clang__)
-//     bin = __builtin_bswap32(bin);
-// #else
-//     // FIXME: `_byteswap_ulong` under MSVC
-//     // TODO: using `std::byteswap` (c++23)
-//     bin = ((bin << 16) & 0xFFFF0000) | ((bin >> 16) & 0x0000FFFF);
-//     bin = ((bin << 8) & 0xFF00FF00) | ((bin >> 8) & 0x00FF00FF);
-// #endif
     bin = ((bin << 4) & 0xF0F0F0F0) | ((bin >> 4) & 0x0F0F0F0F);
     return ((bin << 2) & 0xCCCCCCCC) | ((bin >> 2) & 0x33333333);
 }
 
+// ----------------------------------------------------------------------------------------- //
+
 /// Empty function calls that generally used for callbacks.
 typedef std::function<void()> Notifier;
 
@@ -97,6 +95,8 @@ private:
     std::list<Task> tasks_;
 };
 
+// ----------------------------------------------------------------------------------------- //
+
 } // namespace klotski
 
 #include "worker.inl"