// Copyright (c) 1994 - 2026 kio@little-bat.de
// BSD-2-Clause license
// https://opensource.org/licenses/BSD-2-Clause

#pragma once
#include <bit>

#if defined __cpp_lib_endian

namespace kilipili
{
static constexpr bool little_endian = std::endian::native == std::endian::little;
static constexpr bool big_endian	= std::endian::native == std::endian::big;
} // namespace kilipili

#else

  #if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)

	#if defined(__BYTE_ORDER__)
	  #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
		#define __LITTLE_ENDIAN__ 1
	  #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
		#define __BIG_ENDIAN__ 1
	  #else
		#error "__PDP_ENDIAN__"
	  #endif

	#elif defined(__FreeBSD__) || defined(__NetBSD__)
	  #include <sys/endian.h>
	  #if defined(_BYTE_ORDER)
		#if _BYTE_ORDER == _LITTLE_ENDIAN
		  #define __LITTLE_ENDIAN__ 1
		#elif _BYTE_ORDER == _BIG_ENDIAN
		  #define __BIG_ENDIAN__ 1
		#else
		  #error "__PDP_ENDIAN__"
		#endif
	  #endif

	#elif defined(_WIN32)
	  #define __LITTLE_ENDIAN__ 1

	#elif defined(__sun__)
	  #include <sys/isa_defs.h>
	  #if defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)
		#define __LITTLE_ENDIAN__ 1
	  #elif defined(_BIG_ENDIAN) && !defined(_LITTLE_ENDIAN)
		#define __BIG_ENDIAN__ 1
	  #endif
	#endif

	#if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
	  #include <endian.h>
	  #if defined(BYTE_ORDER)
		#if BYTE_ORDER == LITTLE_ENDIAN
		  #define __LITTLE_ENDIAN__ 1
		#elif BYTE_ORDER == BIG_ENDIAN
		  #define __BIG_ENDIAN__ 1
		#else
		  #error "__PDP_ENDIAN__"
		#endif
	  #elif defined(__BYTE_ORDER)
		#if __BYTE_ORDER == __LITTLE_ENDIAN
		  #define __LITTLE_ENDIAN__ 1
		#elif __BYTE_ORDER == __BIG_ENDIAN
		  #define __BIG_ENDIAN__ 1
		#else
		  #error "__PDP_ENDIAN__"
		#endif
	  #elif defined(_BYTE_ORDER)
		#if _BYTE_ORDER == _LITTLE_ENDIAN
		  #define __LITTLE_ENDIAN__ 1
		#elif _BYTE_ORDER == _BIG_ENDIAN
		  #define __BIG_ENDIAN__ 1
		#else
		  #error "__PDP_ENDIAN__"
		#endif
	  #endif
	#endif
  #endif

namespace kilipili
{
  #if defined __LITTLE_ENDIAN__ && __LITTLE_ENDIAN__
static constexpr bool little_endian = 1;
static constexpr bool big_endian	= 0;
  #elif defined __BIG_ENDIAN__ && __BIG_ENDIAN__
static constexpr bool little_endian = 0;
static constexpr bool big_endian	= 1;
  #endif
} // namespace kilipili

#endif