#ifndef _EXOPT_H
#define _EXOPT_H

#define _EO__OPT_OLD_ASSUME //XXX: __attribute__((gnu::assume(X))) fails to build

#define _EXOPT_INTERNAL_PREFIX _exopt__

#ifdef __cplusplus
#	define _exopt__cpp 1
#	define _exopt__c 1
extern "C" {
#else
#	define _exopt__cpp 0
#	define _exopt__c 1
#endif

#define _EO_PASTE_(x,y) x##y
#define _EO_PASTE(x,y) _EO_PASTE_(x,y)
#define _EO(X) _EO_PASTE(_EXOPT_INTERNAL_PREFIX, X)


#define _exopt__internal __attribute__((visibility("internal")))
#define _exopt__readonly __attribute__((__pure__))
#define _exopt__pure __attribute__((__const__))

#ifdef _EO__OPT_OLD_ASSUME
#	define _EO_ASSUME(X) ({ if(! (X)) __builtin_unreachable(); })
#endif

#define _EO_NOTHING

#if _EO(cpp)
#	ifndef _EO_ASSUME
#		define _EO_ASSUME(X) [[gnu::assume(X)]]
#	endif
#	define _exopt__restrict __restrict__
#define _EO_CTORS_BASIC_W(N, constexpr, noexcept, ...) \
		constexpr N(N const&) noexcept __VA_ARGS__; \
		constexpr N(N &&) noexcept __VA_ARGS__; \
		constexpr N & operator=(N const&) noexcept __VA_ARGS__; \
		constexpr N & operator=(N &&) noexcept __VA_ARGS__
#define _EO_CTORS_BASIC(...) _EO_CTORS_BASIC_W(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)
#define _EO_CTORS_BASIC_DEFAULT(...) _EO_CTORS_BASIC(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, = default)

#define _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, noexcept, ...) \
		constexpr N(N const&) noexcept = default; \
		constexpr N(N &&) noexcept = default; \
		constexpr N & operator=(N const&) noexcept = default; \
		constexpr N & operator=(N &&) noexcept = default

#define _EO_CTORS_DEFAULT_BASIC(N) _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, _EO_NOTHING, _EO_NOTHING)
#define _EO_CTORS_DEFAULT_BASIC_RT(N) _EO_CTORS_DEFAULT_BASIC_W(N, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)
#define _EO_CTORS_DEFAULT_BASIC_NE_W(N, C) _EO_CTORS_DEFAULT_BASIC_W(N, C, noexcept, _EO_NOTHING)
#define _EO_CTORS_DEFAULT_BASIC_NE(N) _EO_CTORS_DEFAULT_BASIC_W(N, constexpr, noexcept, _EO_NOTHING)
#define _EO_CTORS_DEFAULT_BASIC_NE_RT(N) _EO_CTORS_DEFAULT_BASIC_W(N, _EO_NOTHING, noexcept, _EO_NOTHING)

#define _EO_CLASS_DEFAULT_(N, ...) N
#define _EO_CLASS_DEFAULT_2(_, N, ...) N
#define _EO_CLASS_DEFAULT_3(_, __, N, ...) N
#define _EO_CLASS_DEFAULT_4(_, __, ___, N, ...) N
#define _EO_CLASS_DEFAULT_3REST(_, __, ___, ...) __VA_ARGS__
#define _EO_CLASS_DEFAULT_4REST(_, __, ___, ____, ...) __VA_ARGS__
// _EO_CLASS_DEFINE(NAME, [constexpr], [noexcept], [virtual], [=default])
#define _EO_CLASS_DEFINE(...) _EO_CTORS_BASIC(__VA_ARGS__); \
				_EO_CLASS_DEFAULT_4(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING) _EO_CLASS_DEFAULT_2(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING) ~ _EO_CLASS_DEFAULT_(__VA_ARGS__, _EO_NOTHING)() _EO_CLASS_DEFAULT_3(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)  _EO_CLASS_DEFAULT_4REST(__VA_ARGS__, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING, _EO_NOTHING)

#else
#	ifndef _EO_ASSUME
#		define _EO_ASSUME(X) __attribute__((assume(X)))
#	endif
#	define _exopt__restrict restrict
#endif

#ifdef __cplusplus
}
#endif

#endif /* _EXOPT_H */