add a basic benchmark for lexer

I suspect std::regex is _horribly_ slow.
Will compare it to boost::regex, then decide.

4 files changed, 41 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 19b6164..65b8732 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,6 +31,9 @@ add_subdirectory(client)
 add_subdirectory(server)
 
 if(ENABLE_TESTS)
+    set(BENCHMARK_ENABLE_TESTING OFF CACHE BOOL "Suppressing benchmark's tests" FORCE)
+    add_subdirectory("3rdparty/google/benchmark")
+
     add_subdirectory(test)
 endif()
 
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index bed23ce..5b81467 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1 +1,2 @@
+add_subdirectory(benchmarks)
 add_subdirectory(unit_tests)
diff --git a/test/benchmarks/CMakeLists.txt b/test/benchmarks/CMakeLists.txt
new file mode 100644
index 0000000..89d9858
--- /dev/null
+++ b/test/benchmarks/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_executable(benchmarks lexer.cpp)
+set_target_properties(benchmarks PROPERTIES OUTPUT_NAME math-server-benchmarks)
+
+target_link_libraries(benchmarks PRIVATE lexer)
+target_include_directories(benchmarks PRIVATE ../..)
+
+target_link_libraries(benchmarks PRIVATE benchmark benchmark_main)
+
+install(TARGETS benchmarks RUNTIME DESTINATION bin)
+if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    install(FILES "$<TARGET_PDB_FILE:benchmarks>" DESTINATION bin OPTIONAL)
+endif()
diff --git a/test/benchmarks/lexer.cpp b/test/benchmarks/lexer.cpp
new file mode 100644
index 0000000..0f3151f
--- /dev/null
+++ b/test/benchmarks/lexer.cpp
@@ -0,0 +1,25 @@
+#include <server/lexer/details/parse.hpp>
+
+#include <benchmark/benchmark.h>
+
+class SelectionOfNumbers : public benchmark::Fixture {
+protected:
+    std::vector<std::string_view> m_numbers{
+        "0",
+        "123",
+        "0.123",
+        ".123",
+        "1e9",
+        "1.87E-18",
+        "012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789.012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789",
+    };
+};
+
+BENCHMARK_F(SelectionOfNumbers, ParseStdRegex)(benchmark::State &state) {
+    using namespace math::server::lexer::details;
+    for (auto _ : state) {
+        for (const auto& src : m_numbers) {
+            parse_number(src);
+        }
+    }
+}