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Diffstat (limited to 'vendor/optional-lite/optional.hpp')
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diff --git a/vendor/optional-lite/optional.hpp b/vendor/optional-lite/optional.hpp new file mode 100644 index 000000000..33a9b987e --- /dev/null +++ b/vendor/optional-lite/optional.hpp @@ -0,0 +1,1698 @@ +// +// Copyright (c) 2014-2018 Martin Moene +// +// https://github.com/martinmoene/optional-lite +// +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE.txt or copy at http://www.boost.org/LICENSE_1_0.txt) + +#pragma once + +#ifndef NONSTD_OPTIONAL_LITE_HPP +#define NONSTD_OPTIONAL_LITE_HPP + +#define optional_lite_MAJOR 3 +#define optional_lite_MINOR 2 +#define optional_lite_PATCH 0 + +#define optional_lite_VERSION optional_STRINGIFY(optional_lite_MAJOR) "." optional_STRINGIFY(optional_lite_MINOR) "." optional_STRINGIFY(optional_lite_PATCH) + +#define optional_STRINGIFY( x ) optional_STRINGIFY_( x ) +#define optional_STRINGIFY_( x ) #x + +// optional-lite configuration: + +#define optional_OPTIONAL_DEFAULT 0 +#define optional_OPTIONAL_NONSTD 1 +#define optional_OPTIONAL_STD 2 + +#if !defined( optional_CONFIG_SELECT_OPTIONAL ) +# define optional_CONFIG_SELECT_OPTIONAL ( optional_HAVE_STD_OPTIONAL ? optional_OPTIONAL_STD : optional_OPTIONAL_NONSTD ) +#endif + +// Control presence of exception handling (try and auto discover): + +#ifndef optional_CONFIG_NO_EXCEPTIONS +# if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND) +# define optional_CONFIG_NO_EXCEPTIONS 0 +# else +# define optional_CONFIG_NO_EXCEPTIONS 1 +# endif +#endif + +// C++ language version detection (C++20 is speculative): +// Note: VC14.0/1900 (VS2015) lacks too much from C++14. + +#ifndef optional_CPLUSPLUS +# if defined(_MSVC_LANG ) && !defined(__clang__) +# define optional_CPLUSPLUS (_MSC_VER == 1900 ? 201103L : _MSVC_LANG ) +# else +# define optional_CPLUSPLUS __cplusplus +# endif +#endif + +#define optional_CPP98_OR_GREATER ( optional_CPLUSPLUS >= 199711L ) +#define optional_CPP11_OR_GREATER ( optional_CPLUSPLUS >= 201103L ) +#define optional_CPP11_OR_GREATER_ ( optional_CPLUSPLUS >= 201103L ) +#define optional_CPP14_OR_GREATER ( optional_CPLUSPLUS >= 201402L ) +#define optional_CPP17_OR_GREATER ( optional_CPLUSPLUS >= 201703L ) +#define optional_CPP20_OR_GREATER ( optional_CPLUSPLUS >= 202000L ) + +// C++ language version (represent 98 as 3): + +#define optional_CPLUSPLUS_V ( optional_CPLUSPLUS / 100 - (optional_CPLUSPLUS > 200000 ? 2000 : 1994) ) + +// Use C++17 std::optional if available and requested: + +#if optional_CPP17_OR_GREATER && defined(__has_include ) +# if __has_include( <optional> ) +# define optional_HAVE_STD_OPTIONAL 1 +# else +# define optional_HAVE_STD_OPTIONAL 0 +# endif +#else +# define optional_HAVE_STD_OPTIONAL 0 +#endif + +#define optional_USES_STD_OPTIONAL ( (optional_CONFIG_SELECT_OPTIONAL == optional_OPTIONAL_STD) || ((optional_CONFIG_SELECT_OPTIONAL == optional_OPTIONAL_DEFAULT) && optional_HAVE_STD_OPTIONAL) ) + +// +// in_place: code duplicated in any-lite, expected-lite, optional-lite, value-ptr-lite, variant-lite: +// + +#ifndef nonstd_lite_HAVE_IN_PLACE_TYPES +#define nonstd_lite_HAVE_IN_PLACE_TYPES 1 + +// C++17 std::in_place in <utility>: + +#if optional_CPP17_OR_GREATER + +#include <utility> + +namespace nonstd { + +using std::in_place; +using std::in_place_type; +using std::in_place_index; +using std::in_place_t; +using std::in_place_type_t; +using std::in_place_index_t; + +#define nonstd_lite_in_place_t( T) std::in_place_t +#define nonstd_lite_in_place_type_t( T) std::in_place_type_t<T> +#define nonstd_lite_in_place_index_t(K) std::in_place_index_t<K> + +#define nonstd_lite_in_place( T) std::in_place_t{} +#define nonstd_lite_in_place_type( T) std::in_place_type_t<T>{} +#define nonstd_lite_in_place_index(K) std::in_place_index_t<K>{} + +} // namespace nonstd + +#else // optional_CPP17_OR_GREATER + +#include <cstddef> + +namespace nonstd { +namespace detail { + +template< class T > +struct in_place_type_tag {}; + +template< std::size_t K > +struct in_place_index_tag {}; + +} // namespace detail + +struct in_place_t {}; + +template< class T > +inline in_place_t in_place( detail::in_place_type_tag<T> /*unused*/ = detail::in_place_type_tag<T>() ) +{ + return in_place_t(); +} + +template< std::size_t K > +inline in_place_t in_place( detail::in_place_index_tag<K> /*unused*/ = detail::in_place_index_tag<K>() ) +{ + return in_place_t(); +} + +template< class T > +inline in_place_t in_place_type( detail::in_place_type_tag<T> /*unused*/ = detail::in_place_type_tag<T>() ) +{ + return in_place_t(); +} + +template< std::size_t K > +inline in_place_t in_place_index( detail::in_place_index_tag<K> /*unused*/ = detail::in_place_index_tag<K>() ) +{ + return in_place_t(); +} + +// mimic templated typedef: + +#define nonstd_lite_in_place_t( T) nonstd::in_place_t(&)( nonstd::detail::in_place_type_tag<T> ) +#define nonstd_lite_in_place_type_t( T) nonstd::in_place_t(&)( nonstd::detail::in_place_type_tag<T> ) +#define nonstd_lite_in_place_index_t(K) nonstd::in_place_t(&)( nonstd::detail::in_place_index_tag<K> ) + +#define nonstd_lite_in_place( T) nonstd::in_place_type<T> +#define nonstd_lite_in_place_type( T) nonstd::in_place_type<T> +#define nonstd_lite_in_place_index(K) nonstd::in_place_index<K> + +} // namespace nonstd + +#endif // optional_CPP17_OR_GREATER +#endif // nonstd_lite_HAVE_IN_PLACE_TYPES + +// +// Using std::optional: +// + +#if optional_USES_STD_OPTIONAL + +#include <optional> + +namespace nonstd { + + using std::optional; + using std::bad_optional_access; + using std::hash; + + using std::nullopt; + using std::nullopt_t; + + using std::operator==; + using std::operator!=; + using std::operator<; + using std::operator<=; + using std::operator>; + using std::operator>=; + using std::make_optional; + using std::swap; +} + +#else // optional_USES_STD_OPTIONAL + +#include <cassert> +#include <utility> + +// optional-lite alignment configuration: + +#ifndef optional_CONFIG_MAX_ALIGN_HACK +# define optional_CONFIG_MAX_ALIGN_HACK 0 +#endif + +#ifndef optional_CONFIG_ALIGN_AS +// no default, used in #if defined() +#endif + +#ifndef optional_CONFIG_ALIGN_AS_FALLBACK +# define optional_CONFIG_ALIGN_AS_FALLBACK double +#endif + +// Compiler warning suppression: + +#if defined(__clang__) +# pragma clang diagnostic push +# pragma clang diagnostic ignored "-Wundef" +#elif defined(__GNUC__) +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Wundef" +#elif defined(_MSC_VER ) +# pragma warning( push ) +#endif + +// half-open range [lo..hi): +#define optional_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) ) + +// Compiler versions: +// +// MSVC++ 6.0 _MSC_VER == 1200 (Visual Studio 6.0) +// MSVC++ 7.0 _MSC_VER == 1300 (Visual Studio .NET 2002) +// MSVC++ 7.1 _MSC_VER == 1310 (Visual Studio .NET 2003) +// MSVC++ 8.0 _MSC_VER == 1400 (Visual Studio 2005) +// MSVC++ 9.0 _MSC_VER == 1500 (Visual Studio 2008) +// MSVC++ 10.0 _MSC_VER == 1600 (Visual Studio 2010) +// MSVC++ 11.0 _MSC_VER == 1700 (Visual Studio 2012) +// MSVC++ 12.0 _MSC_VER == 1800 (Visual Studio 2013) +// MSVC++ 14.0 _MSC_VER == 1900 (Visual Studio 2015) +// MSVC++ 14.1 _MSC_VER >= 1910 (Visual Studio 2017) + +#if defined(_MSC_VER ) && !defined(__clang__) +# define optional_COMPILER_MSVC_VER (_MSC_VER ) +# define optional_COMPILER_MSVC_VERSION (_MSC_VER / 10 - 10 * ( 5 + (_MSC_VER < 1900 ) ) ) +#else +# define optional_COMPILER_MSVC_VER 0 +# define optional_COMPILER_MSVC_VERSION 0 +#endif + +#define optional_COMPILER_VERSION( major, minor, patch ) ( 10 * (10 * (major) + (minor) ) + (patch) ) + +#if defined(__GNUC__) && !defined(__clang__) +# define optional_COMPILER_GNUC_VERSION optional_COMPILER_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__) +#else +# define optional_COMPILER_GNUC_VERSION 0 +#endif + +#if defined(__clang__) +# define optional_COMPILER_CLANG_VERSION optional_COMPILER_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__) +#else +# define optional_COMPILER_CLANG_VERSION 0 +#endif + +#if optional_BETWEEN(optional_COMPILER_MSVC_VERSION, 70, 140 ) +# pragma warning( disable: 4345 ) // initialization behavior changed +#endif + +#if optional_BETWEEN(optional_COMPILER_MSVC_VERSION, 70, 150 ) +# pragma warning( disable: 4814 ) // in C++14 'constexpr' will not imply 'const' +#endif + +// Presence of language and library features: + +#define optional_HAVE(FEATURE) ( optional_HAVE_##FEATURE ) + +#ifdef _HAS_CPP0X +# define optional_HAS_CPP0X _HAS_CPP0X +#else +# define optional_HAS_CPP0X 0 +#endif + +// Unless defined otherwise below, consider VC14 as C++11 for optional-lite: + +#if optional_COMPILER_MSVC_VER >= 1900 +# undef optional_CPP11_OR_GREATER +# define optional_CPP11_OR_GREATER 1 +#endif + +#define optional_CPP11_90 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1500) +#define optional_CPP11_100 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1600) +#define optional_CPP11_110 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1700) +#define optional_CPP11_120 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1800) +#define optional_CPP11_140 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1900) +#define optional_CPP11_141 (optional_CPP11_OR_GREATER_ || optional_COMPILER_MSVC_VER >= 1910) + +#define optional_CPP14_000 (optional_CPP14_OR_GREATER) +#define optional_CPP17_000 (optional_CPP17_OR_GREATER) + +// Presence of C++11 language features: + +#define optional_HAVE_CONSTEXPR_11 optional_CPP11_140 +#define optional_HAVE_IS_DEFAULT optional_CPP11_140 +#define optional_HAVE_NOEXCEPT optional_CPP11_140 +#define optional_HAVE_NULLPTR optional_CPP11_100 +#define optional_HAVE_REF_QUALIFIER optional_CPP11_140 + +// Presence of C++14 language features: + +#define optional_HAVE_CONSTEXPR_14 optional_CPP14_000 + +// Presence of C++17 language features: + +#define optional_HAVE_NODISCARD optional_CPP17_000 + +// Presence of C++ library features: + +#define optional_HAVE_CONDITIONAL optional_CPP11_120 +#define optional_HAVE_REMOVE_CV optional_CPP11_120 +#define optional_HAVE_TYPE_TRAITS optional_CPP11_90 + +#define optional_HAVE_TR1_TYPE_TRAITS (!! optional_COMPILER_GNUC_VERSION ) +#define optional_HAVE_TR1_ADD_POINTER (!! optional_COMPILER_GNUC_VERSION ) + +// C++ feature usage: + +#if optional_HAVE( CONSTEXPR_11 ) +# define optional_constexpr constexpr +#else +# define optional_constexpr /*constexpr*/ +#endif + +#if optional_HAVE( IS_DEFAULT ) +# define optional_is_default = default; +#else +# define optional_is_default {} +#endif + +#if optional_HAVE( CONSTEXPR_14 ) +# define optional_constexpr14 constexpr +#else +# define optional_constexpr14 /*constexpr*/ +#endif + +#if optional_HAVE( NODISCARD ) +# define optional_nodiscard [[nodiscard]] +#else +# define optional_nodiscard /*[[nodiscard]]*/ +#endif + +#if optional_HAVE( NOEXCEPT ) +# define optional_noexcept noexcept +#else +# define optional_noexcept /*noexcept*/ +#endif + +#if optional_HAVE( NULLPTR ) +# define optional_nullptr nullptr +#else +# define optional_nullptr NULL +#endif + +#if optional_HAVE( REF_QUALIFIER ) +// NOLINTNEXTLINE( bugprone-macro-parentheses ) +# define optional_ref_qual & +# define optional_refref_qual && +#else +# define optional_ref_qual /*&*/ +# define optional_refref_qual /*&&*/ +#endif + +// additional includes: + +#if optional_CONFIG_NO_EXCEPTIONS +// already included: <cassert> +#else +# include <stdexcept> +#endif + +#if optional_CPP11_OR_GREATER +# include <functional> +#endif + +#if optional_HAVE( INITIALIZER_LIST ) +# include <initializer_list> +#endif + +#if optional_HAVE( TYPE_TRAITS ) +# include <type_traits> +#elif optional_HAVE( TR1_TYPE_TRAITS ) +# include <tr1/type_traits> +#endif + +// Method enabling + +#if optional_CPP11_OR_GREATER + +#define optional_REQUIRES_0(...) \ + template< bool B = (__VA_ARGS__), typename std::enable_if<B, int>::type = 0 > + +#define optional_REQUIRES_T(...) \ + , typename = typename std::enable_if< (__VA_ARGS__), nonstd::optional_lite::detail::enabler >::type + +#define optional_REQUIRES_R(R, ...) \ + typename std::enable_if< (__VA_ARGS__), R>::type + +#define optional_REQUIRES_A(...) \ + , typename std::enable_if< (__VA_ARGS__), void*>::type = nullptr + +#endif + +// +// optional: +// + +namespace nonstd { namespace optional_lite { + +namespace std11 { + +#if optional_CPP11_OR_GREATER + using std::move; +#else + template< typename T > T & move( T & t ) { return t; } +#endif + +#if optional_HAVE( CONDITIONAL ) + using std::conditional; +#else + template< bool B, typename T, typename F > struct conditional { typedef T type; }; + template< typename T, typename F > struct conditional<false, T, F> { typedef F type; }; +#endif // optional_HAVE_CONDITIONAL + +} // namespace std11 + +#if optional_CPP11_OR_GREATER + +/// type traits C++17: + +namespace std17 { + +#if optional_CPP17_OR_GREATER + +using std::is_swappable; +using std::is_nothrow_swappable; + +#elif optional_CPP11_OR_GREATER + +namespace detail { + +using std::swap; + +struct is_swappable +{ + template< typename T, typename = decltype( swap( std::declval<T&>(), std::declval<T&>() ) ) > + static std::true_type test( int /*unused*/ ); + + template< typename > + static std::false_type test(...); +}; + +struct is_nothrow_swappable +{ + // wrap noexcept(expr) in separate function as work-around for VC140 (VS2015): + + template< typename T > + static constexpr bool satisfies() + { + return noexcept( swap( std::declval<T&>(), std::declval<T&>() ) ); + } + + template< typename T > + static auto test( int /*unused*/ ) -> std::integral_constant<bool, satisfies<T>()>{} + + template< typename > + static auto test(...) -> std::false_type; +}; + +} // namespace detail + +// is [nothow] swappable: + +template< typename T > +struct is_swappable : decltype( detail::is_swappable::test<T>(0) ){}; + +template< typename T > +struct is_nothrow_swappable : decltype( detail::is_nothrow_swappable::test<T>(0) ){}; + +#endif // optional_CPP17_OR_GREATER + +} // namespace std17 + +/// type traits C++20: + +namespace std20 { + +template< typename T > +struct remove_cvref +{ + typedef typename std::remove_cv< typename std::remove_reference<T>::type >::type type; +}; + +} // namespace std20 + +#endif // optional_CPP11_OR_GREATER + +/// class optional + +template< typename T > +class optional; + +namespace detail { + +// for optional_REQUIRES_T + +#if optional_CPP11_OR_GREATER +enum class enabler{}; +#endif + +// C++11 emulation: + +struct nulltype{}; + +template< typename Head, typename Tail > +struct typelist +{ + typedef Head head; + typedef Tail tail; +}; + +#if optional_CONFIG_MAX_ALIGN_HACK + +// Max align, use most restricted type for alignment: + +#define optional_UNIQUE( name ) optional_UNIQUE2( name, __LINE__ ) +#define optional_UNIQUE2( name, line ) optional_UNIQUE3( name, line ) +#define optional_UNIQUE3( name, line ) name ## line + +#define optional_ALIGN_TYPE( type ) \ + type optional_UNIQUE( _t ); struct_t< type > optional_UNIQUE( _st ) + +template< typename T > +struct struct_t { T _; }; + +union max_align_t +{ + optional_ALIGN_TYPE( char ); + optional_ALIGN_TYPE( short int ); + optional_ALIGN_TYPE( int ); + optional_ALIGN_TYPE( long int ); + optional_ALIGN_TYPE( float ); + optional_ALIGN_TYPE( double ); + optional_ALIGN_TYPE( long double ); + optional_ALIGN_TYPE( char * ); + optional_ALIGN_TYPE( short int * ); + optional_ALIGN_TYPE( int * ); + optional_ALIGN_TYPE( long int * ); + optional_ALIGN_TYPE( float * ); + optional_ALIGN_TYPE( double * ); + optional_ALIGN_TYPE( long double * ); + optional_ALIGN_TYPE( void * ); + +#ifdef HAVE_LONG_LONG + optional_ALIGN_TYPE( long long ); +#endif + + struct Unknown; + + Unknown ( * optional_UNIQUE(_) )( Unknown ); + Unknown * Unknown::* optional_UNIQUE(_); + Unknown ( Unknown::* optional_UNIQUE(_) )( Unknown ); + + struct_t< Unknown ( * )( Unknown) > optional_UNIQUE(_); + struct_t< Unknown * Unknown::* > optional_UNIQUE(_); + struct_t< Unknown ( Unknown::* )(Unknown) > optional_UNIQUE(_); +}; + +#undef optional_UNIQUE +#undef optional_UNIQUE2 +#undef optional_UNIQUE3 + +#undef optional_ALIGN_TYPE + +#elif defined( optional_CONFIG_ALIGN_AS ) // optional_CONFIG_MAX_ALIGN_HACK + +// Use user-specified type for alignment: + +#define optional_ALIGN_AS( unused ) \ + optional_CONFIG_ALIGN_AS + +#else // optional_CONFIG_MAX_ALIGN_HACK + +// Determine POD type to use for alignment: + +#define optional_ALIGN_AS( to_align ) \ + typename type_of_size< alignment_types, alignment_of< to_align >::value >::type + +template< typename T > +struct alignment_of; + +template< typename T > +struct alignment_of_hack +{ + char c; + T t; + alignment_of_hack(); +}; + +template< size_t A, size_t S > +struct alignment_logic +{ + enum { value = A < S ? A : S }; +}; + +template< typename T > +struct alignment_of +{ + enum { value = alignment_logic< + sizeof( alignment_of_hack<T> ) - sizeof(T), sizeof(T) >::value }; +}; + +template< typename List, size_t N > +struct type_of_size +{ + typedef typename std11::conditional< + N == sizeof( typename List::head ), + typename List::head, + typename type_of_size<typename List::tail, N >::type >::type type; +}; + +template< size_t N > +struct type_of_size< nulltype, N > +{ + typedef optional_CONFIG_ALIGN_AS_FALLBACK type; +}; + +template< typename T> +struct struct_t { T _; }; + +#define optional_ALIGN_TYPE( type ) \ + typelist< type , typelist< struct_t< type > + +struct Unknown; + +typedef + optional_ALIGN_TYPE( char ), + optional_ALIGN_TYPE( short ), + optional_ALIGN_TYPE( int ), + optional_ALIGN_TYPE( long ), + optional_ALIGN_TYPE( float ), + optional_ALIGN_TYPE( double ), + optional_ALIGN_TYPE( long double ), + + optional_ALIGN_TYPE( char *), + optional_ALIGN_TYPE( short * ), + optional_ALIGN_TYPE( int * ), + optional_ALIGN_TYPE( long * ), + optional_ALIGN_TYPE( float * ), + optional_ALIGN_TYPE( double * ), + optional_ALIGN_TYPE( long double * ), + + optional_ALIGN_TYPE( Unknown ( * )( Unknown ) ), + optional_ALIGN_TYPE( Unknown * Unknown::* ), + optional_ALIGN_TYPE( Unknown ( Unknown::* )( Unknown ) ), + + nulltype + > > > > > > > > > > > > > > + > > > > > > > > > > > > > > + > > > > > > + alignment_types; + +#undef optional_ALIGN_TYPE + +#endif // optional_CONFIG_MAX_ALIGN_HACK + +/// C++03 constructed union to hold value. + +template< typename T > +union storage_t +{ +//private: +// template< typename > friend class optional; + + typedef T value_type; + + storage_t() optional_is_default + + explicit storage_t( value_type const & v ) + { + construct_value( v ); + } + + void construct_value( value_type const & v ) + { + ::new( value_ptr() ) value_type( v ); + } + +#if optional_CPP11_OR_GREATER + + explicit storage_t( value_type && v ) + { + construct_value( std::move( v ) ); + } + + void construct_value( value_type && v ) + { + ::new( value_ptr() ) value_type( std::move( v ) ); + } + + template< class... Args > + void emplace( Args&&... args ) + { + ::new( value_ptr() ) value_type( std::forward<Args>(args)... ); + } + + template< class U, class... Args > + void emplace( std::initializer_list<U> il, Args&&... args ) + { + ::new( value_ptr() ) value_type( il, std::forward<Args>(args)... ); + } + +#endif + + void destruct_value() + { + value_ptr()->~T(); + } + + optional_nodiscard value_type const * value_ptr() const + { + return as<value_type>(); + } + + value_type * value_ptr() + { + return as<value_type>(); + } + + optional_nodiscard value_type const & value() const optional_ref_qual + { + return * value_ptr(); + } + + value_type & value() optional_ref_qual + { + return * value_ptr(); + } + +#if optional_CPP11_OR_GREATER + + optional_nodiscard value_type const && value() const optional_refref_qual + { + return std::move( value() ); + } + + value_type && value() optional_refref_qual + { + return std::move( value() ); + } + +#endif + +#if optional_CPP11_OR_GREATER + + using aligned_storage_t = typename std::aligned_storage< sizeof(value_type), alignof(value_type) >::type; + aligned_storage_t data; + +#elif optional_CONFIG_MAX_ALIGN_HACK + + typedef struct { unsigned char data[ sizeof(value_type) ]; } aligned_storage_t; + + max_align_t hack; + aligned_storage_t data; + +#else + typedef optional_ALIGN_AS(value_type) align_as_type; + + typedef struct { align_as_type data[ 1 + ( sizeof(value_type) - 1 ) / sizeof(align_as_type) ]; } aligned_storage_t; + aligned_storage_t data; + +# undef optional_ALIGN_AS + +#endif // optional_CONFIG_MAX_ALIGN_HACK + + optional_nodiscard void * ptr() optional_noexcept + { + return &data; + } + + optional_nodiscard void const * ptr() const optional_noexcept + { + return &data; + } + + template <typename U> + optional_nodiscard U * as() + { + return reinterpret_cast<U*>( ptr() ); + } + + template <typename U> + optional_nodiscard U const * as() const + { + return reinterpret_cast<U const *>( ptr() ); + } +}; + +} // namespace detail + +/// disengaged state tag + +struct nullopt_t +{ + struct init{}; + explicit optional_constexpr nullopt_t( init /*unused*/ ) optional_noexcept {} +}; + +#if optional_HAVE( CONSTEXPR_11 ) +constexpr nullopt_t nullopt{ nullopt_t::init{} }; +#else +// extra parenthesis to prevent the most vexing parse: +const nullopt_t nullopt(( nullopt_t::init() )); +#endif + +/// optional access error + +#if ! optional_CONFIG_NO_EXCEPTIONS + +class bad_optional_access : public std::logic_error +{ +public: + explicit bad_optional_access() + : logic_error( "bad optional access" ) {} +}; + +#endif //optional_CONFIG_NO_EXCEPTIONS + +/// optional + +template< typename T> +class optional +{ +private: + template< typename > friend class optional; + + typedef void (optional::*safe_bool)() const; + +public: + typedef T value_type; + + // x.x.3.1, constructors + + // 1a - default construct + optional_constexpr optional() optional_noexcept + : has_value_( false ) + , contained() + {} + + // 1b - construct explicitly empty + // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions ) + optional_constexpr optional( nullopt_t /*unused*/ ) optional_noexcept + : has_value_( false ) + , contained() + {} + + // 2 - copy-construct + optional_constexpr14 optional( optional const & other +#if optional_CPP11_OR_GREATER + optional_REQUIRES_A( + true || std::is_copy_constructible<T>::value + ) +#endif + ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( other.contained.value() ); + } + } + +#if optional_CPP11_OR_GREATER + + // 3 (C++11) - move-construct from optional + optional_constexpr14 optional( optional && other + optional_REQUIRES_A( + true || std::is_move_constructible<T>::value + ) + // NOLINTNEXTLINE( performance-noexcept-move-constructor ) + ) noexcept( std::is_nothrow_move_constructible<T>::value ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( std::move( other.contained.value() ) ); + } + } + + // 4a (C++11) - explicit converting copy-construct from optional + template< typename U > + explicit optional( optional<U> const & other + optional_REQUIRES_A( + std::is_constructible<T, U const &>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && !std::is_convertible< U const & , T>::value /*=> explicit */ + ) + ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( T{ other.contained.value() } ); + } + } +#endif // optional_CPP11_OR_GREATER + + // 4b (C++98 and later) - non-explicit converting copy-construct from optional + template< typename U > + // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions ) + optional( optional<U> const & other +#if optional_CPP11_OR_GREATER + optional_REQUIRES_A( + std::is_constructible<T, U const &>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && std::is_convertible< U const & , T>::value /*=> non-explicit */ + ) +#endif // optional_CPP11_OR_GREATER + ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( other.contained.value() ); + } + } + +#if optional_CPP11_OR_GREATER + + // 5a (C++11) - explicit converting move-construct from optional + template< typename U > + explicit optional( optional<U> && other + optional_REQUIRES_A( + std::is_constructible<T, U &&>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && !std::is_convertible< U &&, T>::value /*=> explicit */ + ) + ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( T{ std::move( other.contained.value() ) } ); + } + } + + // 5a (C++11) - non-explicit converting move-construct from optional + template< typename U > + // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions ) + optional( optional<U> && other + optional_REQUIRES_A( + std::is_constructible<T, U &&>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && std::is_convertible< U &&, T>::value /*=> non-explicit */ + ) + ) + : has_value_( other.has_value() ) + { + if ( other.has_value() ) + { + contained.construct_value( std::move( other.contained.value() ) ); + } + } + + // 6 (C++11) - in-place construct + template< typename... Args + optional_REQUIRES_T( + std::is_constructible<T, Args&&...>::value + ) + > + optional_constexpr explicit optional( nonstd_lite_in_place_t(T), Args&&... args ) + : has_value_( true ) + , contained( T( std::forward<Args>(args)...) ) + {} + + // 7 (C++11) - in-place construct, initializer-list + template< typename U, typename... Args + optional_REQUIRES_T( + std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value + ) + > + optional_constexpr explicit optional( nonstd_lite_in_place_t(T), std::initializer_list<U> il, Args&&... args ) + : has_value_( true ) + , contained( T( il, std::forward<Args>(args)...) ) + {} + + // 8a (C++11) - explicit move construct from value + template< typename U = value_type > + optional_constexpr explicit optional( U && value + optional_REQUIRES_A( + std::is_constructible<T, U&&>::value + && !std::is_same<typename std20::remove_cvref<U>::type, nonstd_lite_in_place_t(U)>::value + && !std::is_same<typename std20::remove_cvref<U>::type, optional<T>>::value + && !std::is_convertible<U&&, T>::value /*=> explicit */ + ) + ) + : has_value_( true ) + , contained( T{ std::forward<U>( value ) } ) + {} + + // 8b (C++11) - non-explicit move construct from value + template< typename U = value_type > + // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions ) + optional_constexpr optional( U && value + optional_REQUIRES_A( + std::is_constructible<T, U&&>::value + && !std::is_same<typename std20::remove_cvref<U>::type, nonstd_lite_in_place_t(U)>::value + && !std::is_same<typename std20::remove_cvref<U>::type, optional<T>>::value + && std::is_convertible<U&&, T>::value /*=> non-explicit */ + ) + ) + : has_value_( true ) + , contained( std::forward<U>( value ) ) + {} + +#else // optional_CPP11_OR_GREATER + + // 8 (C++98) + optional( value_type const & value ) + : has_value_( true ) + , contained( value ) + {} + +#endif // optional_CPP11_OR_GREATER + + // x.x.3.2, destructor + + ~optional() + { + if ( has_value() ) + { + contained.destruct_value(); + } + } + + // x.x.3.3, assignment + + // 1 (C++98and later) - assign explicitly empty + optional & operator=( nullopt_t /*unused*/) optional_noexcept + { + reset(); + return *this; + } + + // 2 (C++98and later) - copy-assign from optional +#if optional_CPP11_OR_GREATER + // NOLINTNEXTLINE( cppcoreguidelines-c-copy-assignment-signature, misc-unconventional-assign-operator ) + optional_REQUIRES_R( + optional &, + true +// std::is_copy_constructible<T>::value +// && std::is_copy_assignable<T>::value + ) + operator=( optional const & other ) + noexcept( + std::is_nothrow_move_assignable<T>::value + && std::is_nothrow_move_constructible<T>::value + ) +#else + optional & operator=( optional const & other ) +#endif + { + if ( (has_value() == true ) && (other.has_value() == false) ) { reset(); } + else if ( (has_value() == false) && (other.has_value() == true ) ) { initialize( *other ); } + else if ( (has_value() == true ) && (other.has_value() == true ) ) { contained.value() = *other; } + return *this; + } + +#if optional_CPP11_OR_GREATER + + // 3 (C++11) - move-assign from optional + // NOLINTNEXTLINE( cppcoreguidelines-c-copy-assignment-signature, misc-unconventional-assign-operator ) + optional_REQUIRES_R( + optional &, + true +// std::is_move_constructible<T>::value +// && std::is_move_assignable<T>::value + ) + operator=( optional && other ) noexcept + { + if ( (has_value() == true ) && (other.has_value() == false) ) { reset(); } + else if ( (has_value() == false) && (other.has_value() == true ) ) { initialize( std::move( *other ) ); } + else if ( (has_value() == true ) && (other.has_value() == true ) ) { contained.value() = std::move( *other ); } + return *this; + } + + // 4 (C++11) - move-assign from value + template< typename U = T > + // NOLINTNEXTLINE( cppcoreguidelines-c-copy-assignment-signature, misc-unconventional-assign-operator ) + optional_REQUIRES_R( + optional &, + std::is_constructible<T , U>::value + && std::is_assignable<T&, U>::value + && !std::is_same<typename std20::remove_cvref<U>::type, nonstd_lite_in_place_t(U)>::value + && !std::is_same<typename std20::remove_cvref<U>::type, optional<T>>::value + && !(std::is_scalar<T>::value && std::is_same<T, typename std::decay<U>::type>::value) + ) + operator=( U && value ) + { + if ( has_value() ) + { + contained.value() = std::forward<U>( value ); + } + else + { + initialize( T( std::forward<U>( value ) ) ); + } + return *this; + } + +#else // optional_CPP11_OR_GREATER + + // 4 (C++98) - copy-assign from value + template< typename U /*= T*/ > + optional & operator=( U const & value ) + { + if ( has_value() ) contained.value() = value; + else initialize( T( value ) ); + return *this; + } + +#endif // optional_CPP11_OR_GREATER + + // 5 (C++98 and later) - converting copy-assign from optional + template< typename U > +#if optional_CPP11_OR_GREATER + // NOLINTNEXTLINE( cppcoreguidelines-c-copy-assignment-signature, misc-unconventional-assign-operator ) + optional_REQUIRES_R( + optional&, + std::is_constructible< T , U const &>::value + && std::is_assignable< T&, U const &>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && !std::is_assignable< T&, optional<U> & >::value + && !std::is_assignable< T&, optional<U> && >::value + && !std::is_assignable< T&, optional<U> const & >::value + && !std::is_assignable< T&, optional<U> const && >::value + ) +#else + optional& +#endif // optional_CPP11_OR_GREATER + operator=( optional<U> const & other ) + { + return *this = optional( other ); + } + +#if optional_CPP11_OR_GREATER + + // 6 (C++11) - converting move-assign from optional + template< typename U > + // NOLINTNEXTLINE( cppcoreguidelines-c-copy-assignment-signature, misc-unconventional-assign-operator ) + optional_REQUIRES_R( + optional&, + std::is_constructible< T , U>::value + && std::is_assignable< T&, U>::value + && !std::is_constructible<T, optional<U> & >::value + && !std::is_constructible<T, optional<U> && >::value + && !std::is_constructible<T, optional<U> const & >::value + && !std::is_constructible<T, optional<U> const && >::value + && !std::is_convertible< optional<U> & , T>::value + && !std::is_convertible< optional<U> && , T>::value + && !std::is_convertible< optional<U> const & , T>::value + && !std::is_convertible< optional<U> const &&, T>::value + && !std::is_assignable< T&, optional<U> & >::value + && !std::is_assignable< T&, optional<U> && >::value + && !std::is_assignable< T&, optional<U> const & >::value + && !std::is_assignable< T&, optional<U> const && >::value + ) + operator=( optional<U> && other ) + { + return *this = optional( std::move( other ) ); + } + + // 7 (C++11) - emplace + template< typename... Args + optional_REQUIRES_T( + std::is_constructible<T, Args&&...>::value + ) + > + T& emplace( Args&&... args ) + { + *this = nullopt; + contained.emplace( std::forward<Args>(args)... ); + has_value_ = true; + return contained.value(); + } + + // 8 (C++11) - emplace, initializer-list + template< typename U, typename... Args + optional_REQUIRES_T( + std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value + ) + > + T& emplace( std::initializer_list<U> il, Args&&... args ) + { + *this = nullopt; + contained.emplace( il, std::forward<Args>(args)... ); + has_value_ = true; + return contained.value(); + } + +#endif // optional_CPP11_OR_GREATER + + // x.x.3.4, swap + + void swap( optional & other ) +#if optional_CPP11_OR_GREATER + noexcept( + std::is_nothrow_move_constructible<T>::value + && std17::is_nothrow_swappable<T>::value + ) +#endif + { + using std::swap; + if ( (has_value() == true ) && (other.has_value() == true ) ) { swap( **this, *other ); } + else if ( (has_value() == false) && (other.has_value() == true ) ) { initialize( std11::move(*other) ); other.reset(); } + else if ( (has_value() == true ) && (other.has_value() == false) ) { other.initialize( std11::move(**this) ); reset(); } + } + + // x.x.3.5, observers + + optional_constexpr value_type const * operator ->() const + { + return assert( has_value() ), + contained.value_ptr(); + } + + optional_constexpr14 value_type * operator ->() + { + return assert( has_value() ), + contained.value_ptr(); + } + + optional_constexpr value_type const & operator *() const optional_ref_qual + { + return assert( has_value() ), + contained.value(); + } + + optional_constexpr14 value_type & operator *() optional_ref_qual + { + return assert( has_value() ), + contained.value(); + } + +#if optional_HAVE( REF_QUALIFIER ) && ( !optional_COMPILER_GNUC_VERSION || optional_COMPILER_GNUC_VERSION >= 490 ) + + optional_constexpr value_type const && operator *() const optional_refref_qual + { + return std::move( **this ); + } + + optional_constexpr14 value_type && operator *() optional_refref_qual + { + return std::move( **this ); + } + +#endif + +#if optional_CPP11_OR_GREATER + optional_constexpr explicit operator bool() const optional_noexcept + { + return has_value(); + } +#else + optional_constexpr operator safe_bool() const optional_noexcept + { + return has_value() ? &optional::this_type_does_not_support_comparisons : 0; + } +#endif + + // NOLINTNEXTLINE( modernize-use-nodiscard ) + /*optional_nodiscard*/ optional_constexpr bool has_value() const optional_noexcept + { + return has_value_; + } + + // NOLINTNEXTLINE( modernize-use-nodiscard ) + /*optional_nodiscard*/ optional_constexpr14 value_type const & value() const optional_ref_qual + { +#if optional_CONFIG_NO_EXCEPTIONS + assert( has_value() ); +#else + if ( ! has_value() ) + { + throw bad_optional_access(); + } +#endif + return contained.value(); + } + + optional_constexpr14 value_type & value() optional_ref_qual + { +#if optional_CONFIG_NO_EXCEPTIONS + assert( has_value() ); +#else + if ( ! has_value() ) + { + throw bad_optional_access(); + } +#endif + return contained.value(); + } + +#if optional_HAVE( REF_QUALIFIER ) && ( !optional_COMPILER_GNUC_VERSION || optional_COMPILER_GNUC_VERSION >= 490 ) + + // NOLINTNEXTLINE( modernize-use-nodiscard ) + /*optional_nodiscard*/ optional_constexpr value_type const && value() const optional_refref_qual + { + return std::move( value() ); + } + + optional_constexpr14 value_type && value() optional_refref_qual + { + return std::move( value() ); + } + +#endif + +#if optional_CPP11_OR_GREATER + + template< typename U > + optional_constexpr value_type value_or( U && v ) const optional_ref_qual + { + return has_value() ? contained.value() : static_cast<T>(std::forward<U>( v ) ); + } + + template< typename U > + optional_constexpr14 value_type value_or( U && v ) optional_refref_qual + { + return has_value() ? std::move( contained.value() ) : static_cast<T>(std::forward<U>( v ) ); + } + +#else + + template< typename U > + optional_constexpr value_type value_or( U const & v ) const + { + return has_value() ? contained.value() : static_cast<value_type>( v ); + } + +#endif // optional_CPP11_OR_GREATER + + // x.x.3.6, modifiers + + void reset() optional_noexcept + { + if ( has_value() ) + { + contained.destruct_value(); + } + + has_value_ = false; + } + +private: + void this_type_does_not_support_comparisons() const {} + + template< typename V > + void initialize( V const & value ) + { + assert( ! has_value() ); + contained.construct_value( value ); + has_value_ = true; + } + +#if optional_CPP11_OR_GREATER + template< typename V > + void initialize( V && value ) + { + assert( ! has_value() ); + contained.construct_value( std::move( value ) ); + has_value_ = true; + } + +#endif + +private: + bool has_value_; + detail::storage_t< value_type > contained; + +}; + +// Relational operators + +template< typename T, typename U > +inline optional_constexpr bool operator==( optional<T> const & x, optional<U> const & y ) +{ + return bool(x) != bool(y) ? false : !bool( x ) ? true : *x == *y; +} + +template< typename T, typename U > +inline optional_constexpr bool operator!=( optional<T> const & x, optional<U> const & y ) +{ + return !(x == y); +} + +template< typename T, typename U > +inline optional_constexpr bool operator<( optional<T> const & x, optional<U> const & y ) +{ + return (!y) ? false : (!x) ? true : *x < *y; +} + +template< typename T, typename U > +inline optional_constexpr bool operator>( optional<T> const & x, optional<U> const & y ) +{ + return (y < x); +} + +template< typename T, typename U > +inline optional_constexpr bool operator<=( optional<T> const & x, optional<U> const & y ) +{ + return !(y < x); +} + +template< typename T, typename U > +inline optional_constexpr bool operator>=( optional<T> const & x, optional<U> const & y ) +{ + return !(x < y); +} + +// Comparison with nullopt + +template< typename T > +inline optional_constexpr bool operator==( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept +{ + return (!x); +} + +template< typename T > +inline optional_constexpr bool operator==( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept +{ + return (!x); +} + +template< typename T > +inline optional_constexpr bool operator!=( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept +{ + return bool(x); +} + +template< typename T > +inline optional_constexpr bool operator!=( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept +{ + return bool(x); +} + +template< typename T > +inline optional_constexpr bool operator<( optional<T> const & /*unused*/, nullopt_t /*unused*/ ) optional_noexcept +{ + return false; +} + +template< typename T > +inline optional_constexpr bool operator<( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept +{ + return bool(x); +} + +template< typename T > +inline optional_constexpr bool operator<=( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept +{ + return (!x); +} + +template< typename T > +inline optional_constexpr bool operator<=( nullopt_t /*unused*/, optional<T> const & /*unused*/ ) optional_noexcept +{ + return true; +} + +template< typename T > +inline optional_constexpr bool operator>( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept +{ + return bool(x); +} + +template< typename T > +inline optional_constexpr bool operator>( nullopt_t /*unused*/, optional<T> const & /*unused*/ ) optional_noexcept +{ + return false; +} + +template< typename T > +inline optional_constexpr bool operator>=( optional<T> const & /*unused*/, nullopt_t /*unused*/ ) optional_noexcept +{ + return true; +} + +template< typename T > +inline optional_constexpr bool operator>=( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept +{ + return (!x); +} + +// Comparison with T + +template< typename T, typename U > +inline optional_constexpr bool operator==( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x == v : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator==( U const & v, optional<T> const & x ) +{ + return bool(x) ? v == *x : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator!=( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x != v : true; +} + +template< typename T, typename U > +inline optional_constexpr bool operator!=( U const & v, optional<T> const & x ) +{ + return bool(x) ? v != *x : true; +} + +template< typename T, typename U > +inline optional_constexpr bool operator<( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x < v : true; +} + +template< typename T, typename U > +inline optional_constexpr bool operator<( U const & v, optional<T> const & x ) +{ + return bool(x) ? v < *x : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator<=( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x <= v : true; +} + +template< typename T, typename U > +inline optional_constexpr bool operator<=( U const & v, optional<T> const & x ) +{ + return bool(x) ? v <= *x : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator>( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x > v : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator>( U const & v, optional<T> const & x ) +{ + return bool(x) ? v > *x : true; +} + +template< typename T, typename U > +inline optional_constexpr bool operator>=( optional<T> const & x, U const & v ) +{ + return bool(x) ? *x >= v : false; +} + +template< typename T, typename U > +inline optional_constexpr bool operator>=( U const & v, optional<T> const & x ) +{ + return bool(x) ? v >= *x : true; +} + +// Specialized algorithms + +template< typename T +#if optional_CPP11_OR_GREATER + optional_REQUIRES_T( + std::is_move_constructible<T>::value + && std17::is_swappable<T>::value ) +#endif +> +void swap( optional<T> & x, optional<T> & y ) +#if optional_CPP11_OR_GREATER + noexcept( noexcept( x.swap(y) ) ) +#endif +{ + x.swap( y ); +} + +#if optional_CPP11_OR_GREATER + +template< typename T > +optional_constexpr optional< typename std::decay<T>::type > make_optional( T && value ) +{ + return optional< typename std::decay<T>::type >( std::forward<T>( value ) ); +} + +template< typename T, typename...Args > +optional_constexpr optional<T> make_optional( Args&&... args ) +{ + return optional<T>( nonstd_lite_in_place(T), std::forward<Args>(args)...); +} + +template< typename T, typename U, typename... Args > +optional_constexpr optional<T> make_optional( std::initializer_list<U> il, Args&&... args ) +{ + return optional<T>( nonstd_lite_in_place(T), il, std::forward<Args>(args)...); +} + +#else + +template< typename T > +optional<T> make_optional( T const & value ) +{ + return optional<T>( value ); +} + +#endif // optional_CPP11_OR_GREATER + +} // namespace optional_lite + +using optional_lite::optional; +using optional_lite::nullopt_t; +using optional_lite::nullopt; +using optional_lite::bad_optional_access; + +using optional_lite::make_optional; + +} // namespace nonstd + +#if optional_CPP11_OR_GREATER + +// specialize the std::hash algorithm: + +namespace std { + +template< class T > +struct hash< nonstd::optional<T> > +{ +public: + std::size_t operator()( nonstd::optional<T> const & v ) const optional_noexcept + { + return bool( v ) ? std::hash<T>{}( *v ) : 0; + } +}; + +} //namespace std + +#endif // optional_CPP11_OR_GREATER + +#if defined(__clang__) +# pragma clang diagnostic pop +#elif defined(__GNUC__) +# pragma GCC diagnostic pop +#elif defined(_MSC_VER ) +# pragma warning( pop ) +#endif + +#endif // optional_USES_STD_OPTIONAL + +#endif // NONSTD_OPTIONAL_LITE_HPP |