feat: add flat_map for optimize JObject

Author: acking-you

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "third-party/parallel-hashmap"]
+	path = third-party/parallel-hashmap
+	url = https://github.com/greg7mdp/parallel-hashmap.git

CMakeLists.txt

@@ -19,17 +19,21 @@ else ()
     set(CMAKE_CXX_STANDARD 17)
 endif ()
 
+message(STATUS "CMAKE_SYSTEM_PROCESSOR:${CMAKE_SYSTEM_PROCESSOR}")
+
 # Detect the architecture
 if (CMAKE_SYSTEM_PROCESSOR MATCHES "^(x86_64|AMD64|i386|i686)$")
     set(ARCH_X86 TRUE)
-elseif (CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm|aarch64)$")
+elseif (CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm|aarch64|arm64)$")
+    message(STATUS "By default, arm enables NEON for simd optimization")
     set(ARCH_ARM TRUE)
 else ()
     set(ARCH_UNKNOWN TRUE)
 endif ()
 
 # Define options for SIMD instruction sets
 option(USE_SIMD "Enable SIMD instructions" ON)
+option(USE_FLAG_HASH_MAP "Enable FlatHashMap" ON)
 
 # These options are only relevant if SIMD is enabled and the architecture is x86
 if ((NOT USE_AVX2 AND (USE_SIMD AND ARCH_X86)) OR USE_SSE4_2)
@@ -67,6 +71,12 @@ endif ()
 
 add_library(ejson ${PROJECT_SOURCE_DIR}/src/ejson/jobject.cc ${PROJECT_SOURCE_DIR}/src/ejson/parser.cc ${PROJECT_SOURCE_DIR}/src/ejson/base64.cc)
 
+if (USE_FLAG_HASH_MAP)
+    message(STATUS "Use FlatHashMap")
+    add_definitions(-DUSE_FLAT_HASH_MAP)
+    target_include_directories(ejson PUBLIC ${PROJECT_SOURCE_DIR}/third-party/parallel-hashmap)
+endif ()
+
 if (USE_SIMD)
     message(STATUS "Use SIMD Flags:${SIMD_FLAGS}")
     target_compile_options(ejson PRIVATE ${SIMD_FLAGS})

src/ejson/jobject.h

@@ -15,6 +15,12 @@
 #include <unordered_set>
 #include <vector>
 
+#ifdef USE_FLAT_HASH_MAP
+
+#include <parallel_hashmap/phmap.h>
+
+#endif
+
 #include "autogen.h"
 #include "noncopyable.h"
 #include "third_part.h"
@@ -35,7 +41,11 @@ using bool_t   = bool;
 using double_t = double;
 using str_t    = string_view;
 using list_t   = std::vector<JObject>;
-using dict_t   = std::unordered_map<str_t, JObject>;
+#ifdef USE_FLAT_HASH_MAP
+using dict_t = phmap::flat_hash_map<str_t, JObject>;
+#else
+using dict_t = std::map<str_t, JObject>;
+#endif
 
 #define EJSON_TYPE_IS(typea, typeb) std::is_same<typea, typeb>::value