fix endian checker

alibaba · Oct 12, 2023 · 3c87843 · 3c87843
1 parent 865ee36
commit 3c87843
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Showing 2 changed files with 64 additions and 4 deletions.
diff --git a/include/ylt/struct_pack/endian_wrapper.hpp b/include/ylt/struct_pack/endian_wrapper.hpp
@@ -14,9 +14,73 @@
  * limitations under the License.
  */
 #pragma once
+#include <type_traits>
+
 #include "reflection.hpp"
 #include "ylt/struct_pack/util.h"
+
 namespace struct_pack::detail {
+#if __cpp_lib_endian >= 201907L
+constexpr inline bool is_system_little_endian =
+    (std::endian::little == std::endian::native);
+static_assert(std::endian::native == std::endian::little ||
+                  std::endian::native == std::endian::big,
+              "struct_pack don't support middle-endian");
+#else
+#define BYTEORDER_LITTLE_ENDIAN 0  // Little endian machine.
+#define BYTEORDER_BIG_ENDIAN 1     // Big endian machine.
+
+//#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+
+#ifndef BYTEORDER_ENDIAN
+// Detect with GCC 4.6's macro.
+#if defined(__BYTE_ORDER__)
+#if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+#elif (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+#define BYTEORDER_ENDIAN BYTEORDER_BIG_ENDIAN
+#else
+#error \
+    "Unknown machine byteorder endianness detected. User needs to define BYTEORDER_ENDIAN."
+#endif
+// Detect with GLIBC's endian.h.
+#elif defined(__GLIBC__)
+#include <endian.h>
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+#elif (__BYTE_ORDER == __BIG_ENDIAN)
+#define BYTEORDER_ENDIAN BYTEORDER_BIG_ENDIAN
+#else
+#error \
+    "Unknown machine byteorder endianness detected. User needs to define BYTEORDER_ENDIAN."
+#endif
+// Detect with _LITTLE_ENDIAN and _BIG_ENDIAN macro.
+#elif defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)
+#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+#elif defined(_BIG_ENDIAN) && !defined(_LITTLE_ENDIAN)
+#define BYTEORDER_ENDIAN BYTEORDER_BIG_ENDIAN
+// Detect with architecture macros.
+#elif defined(__sparc) || defined(__sparc__) || defined(_POWER) || \
+    defined(__powerpc__) || defined(__ppc__) || defined(__hpux) || \
+    defined(__hppa) || defined(_MIPSEB) || defined(_POWER) ||      \
+    defined(__s390__)
+#define BYTEORDER_ENDIAN BYTEORDER_BIG_ENDIAN
+#elif defined(__i386__) || defined(__alpha__) || defined(__ia64) ||  \
+    defined(__ia64__) || defined(_M_IX86) || defined(_M_IA64) ||     \
+    defined(_M_ALPHA) || defined(__amd64) || defined(__amd64__) ||   \
+    defined(_M_AMD64) || defined(__x86_64) || defined(__x86_64__) || \
+    defined(_M_X64) || defined(__bfin__)
+#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
+#define BYTEORDER_ENDIAN BYTEORDER_LITTLE_ENDIAN
+#else
+#error \
+    "Unknown machine byteorder endianness detected. User needs to define BYTEORDER_ENDIAN."
+#endif
+#endif
+constexpr inline bool is_system_little_endian =
+    (BYTEORDER_ENDIAN == BYTEORDER_LITTLE_ENDIAN);
+#endif
 
 template <std::size_t block_size, typename writer_t>
 void write_wrapper(writer_t& writer, const char* data) {

diff --git a/include/ylt/struct_pack/reflection.hpp b/include/ylt/struct_pack/reflection.hpp
@@ -39,11 +39,7 @@
 namespace struct_pack {
 namespace detail {
 
-constexpr inline bool is_system_little_endian_impl(int value = 0x01) {
-  return static_cast<const unsigned char &>(value) == 1;
-}
 
-constexpr inline bool is_system_little_endian = is_system_little_endian_impl();
 
 template <typename... Args>
 using get_args_type = remove_cvref_t<typename std::conditional<