--- /dev/null
+//
+// Copyright (c) 2014-2021 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 5
+#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
+
+// tweak header support:
+
+#ifdef __has_include
+# if __has_include(<nonstd/optional.tweak.hpp>)
+# include <nonstd/optional.tweak.hpp>
+# endif
+#define optional_HAVE_TWEAK_HEADER 1
+#else
+#define optional_HAVE_TWEAK_HEADER 0
+//# pragma message("optional.hpp: Note: Tweak header not supported.")
+#endif
+
+// optional selection and configuration:
+
+#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 extensions:
+
+#ifndef optional_CONFIG_NO_EXTENSIONS
+#define optional_CONFIG_NO_EXTENSIONS 0
+#endif
+
+// Control presence of exception handling (try and auto discover):
+
+#ifndef optional_CONFIG_NO_EXCEPTIONS
+# if defined(_MSC_VER)
+# include <cstddef> // for _HAS_EXCEPTIONS
+# endif
+# if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || (_HAS_EXCEPTIONS)
+# 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 optional_COMPILER_MSVC_VERSION == 60 (Visual Studio 6.0)
+// MSVC++ 7.0 _MSC_VER == 1300 optional_COMPILER_MSVC_VERSION == 70 (Visual Studio .NET 2002)
+// MSVC++ 7.1 _MSC_VER == 1310 optional_COMPILER_MSVC_VERSION == 71 (Visual Studio .NET 2003)
+// MSVC++ 8.0 _MSC_VER == 1400 optional_COMPILER_MSVC_VERSION == 80 (Visual Studio 2005)
+// MSVC++ 9.0 _MSC_VER == 1500 optional_COMPILER_MSVC_VERSION == 90 (Visual Studio 2008)
+// MSVC++ 10.0 _MSC_VER == 1600 optional_COMPILER_MSVC_VERSION == 100 (Visual Studio 2010)
+// MSVC++ 11.0 _MSC_VER == 1700 optional_COMPILER_MSVC_VERSION == 110 (Visual Studio 2012)
+// MSVC++ 12.0 _MSC_VER == 1800 optional_COMPILER_MSVC_VERSION == 120 (Visual Studio 2013)
+// MSVC++ 14.0 _MSC_VER == 1900 optional_COMPILER_MSVC_VERSION == 140 (Visual Studio 2015)
+// MSVC++ 14.1 _MSC_VER >= 1910 optional_COMPILER_MSVC_VERSION == 141 (Visual Studio 2017)
+// MSVC++ 14.2 _MSC_VER >= 1920 optional_COMPILER_MSVC_VERSION == 142 (Visual Studio 2019)
+
+#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)
+
+// clang >= 2.9, gcc >= 4.9, msvc >= vc14.0/1900 (vs15):
+#define optional_CPP11_140_C290_G490 ((optional_CPP11_OR_GREATER_ && (optional_COMPILER_CLANG_VERSION >= 290 || optional_COMPILER_GNUC_VERSION >= 490)) || (optional_COMPILER_MSVC_VER >= 1900))
+
+// clang >= 3.5, msvc >= vc11 (vs12):
+#define optional_CPP11_110_C350 ( optional_CPP11_110 && !optional_BETWEEN( optional_COMPILER_CLANG_VERSION, 1, 350 ) )
+
+// clang >= 3.5, gcc >= 5.0, msvc >= vc11 (vs12):
+#define optional_CPP11_110_C350_G500 \
+ ( optional_CPP11_110 && \
+ !( optional_BETWEEN( optional_COMPILER_CLANG_VERSION, 1, 350 ) \
+ || optional_BETWEEN( optional_COMPILER_GNUC_VERSION , 1, 500 ) ) )
+
+// 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_C290_G490
+#define optional_HAVE_STATIC_ASSERT optional_CPP11_110
+#define optional_HAVE_INITIALIZER_LIST 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 )
+
+#define optional_HAVE_IS_ASSIGNABLE optional_CPP11_110_C350
+#define optional_HAVE_IS_MOVE_CONSTRUCTIBLE optional_CPP11_110_C350
+#define optional_HAVE_IS_NOTHROW_MOVE_ASSIGNABLE optional_CPP11_110_C350
+#define optional_HAVE_IS_NOTHROW_MOVE_CONSTRUCTIBLE optional_CPP11_110_C350
+#define optional_HAVE_IS_TRIVIALLY_COPY_CONSTRUCTIBLE optional_CPP11_110_C350_G500
+#define optional_HAVE_IS_TRIVIALLY_MOVE_CONSTRUCTIBLE optional_CPP11_110_C350_G500
+
+// 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
+
+#if optional_HAVE( STATIC_ASSERT )
+# define optional_static_assert(expr, text) static_assert(expr, text);
+#else
+# define optional_static_assert(expr, text) /*static_assert(expr, text);*/
+#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 std::enable_if< (__VA_ARGS__), int >::type = 0
+
+#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 {
+
+template< class T, T v > struct integral_constant { enum { value = v }; };
+template< bool B > struct bool_constant : integral_constant<bool, B>{};
+
+typedef bool_constant< true > true_type;
+typedef bool_constant< false > false_type;
+
+#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
+
+#if optional_HAVE( IS_ASSIGNABLE )
+ using std::is_assignable;
+#else
+ template< class T, class U > struct is_assignable : std11::true_type{};
+#endif
+
+#if optional_HAVE( IS_MOVE_CONSTRUCTIBLE )
+ using std::is_move_constructible;
+#else
+ template< class T > struct is_move_constructible : std11::true_type{};
+#endif
+
+#if optional_HAVE( IS_NOTHROW_MOVE_ASSIGNABLE )
+ using std::is_nothrow_move_assignable;
+#else
+ template< class T > struct is_nothrow_move_assignable : std11::true_type{};
+#endif
+
+#if optional_HAVE( IS_NOTHROW_MOVE_CONSTRUCTIBLE )
+ using std::is_nothrow_move_constructible;
+#else
+ template< class T > struct is_nothrow_move_constructible : std11::true_type{};
+#endif
+
+#if optional_HAVE( IS_TRIVIALLY_COPY_CONSTRUCTIBLE )
+ using std::is_trivially_copy_constructible;
+#else
+ template< class T > struct is_trivially_copy_constructible : std11::true_type{};
+#endif
+
+#if optional_HAVE( IS_TRIVIALLY_MOVE_CONSTRUCTIBLE )
+ using std::is_trivially_move_constructible;
+#else
+ template< class T > struct is_trivially_move_constructible : std11::true_type{};
+#endif
+
+} // 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 std11::true_type test( int /*unused*/ );
+
+ template< typename >
+ static std11::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*/ ) -> std11::integral_constant<bool, satisfies<T>()>{}
+
+ template< typename >
+ static auto test(...) -> std11::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 {
+
+// 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 >
+ storage_t( nonstd_lite_in_place_t(T), Args&&... args )
+ {
+ emplace( std::forward<Args>(args)... );
+ }
+
+ 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_HAVE( REF_QUALIFIER )
+
+ 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
+{
+ optional_static_assert(( !std::is_same<typename std::remove_cv<T>::type, nullopt_t>::value ),
+ "T in optional<T> must not be of type 'nullopt_t'.")
+
+ optional_static_assert(( !std::is_same<typename std::remove_cv<T>::type, in_place_t>::value ),
+ "T in optional<T> must not be of type 'in_place_t'.")
+
+ optional_static_assert(( std::is_object<T>::value && std::is_destructible<T>::value && !std::is_array<T>::value ),
+ "T in optional<T> must meet the Cpp17Destructible requirements.")
+
+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
+#if optional_CPP11_OR_GREATER
+ // template< typename U = T
+ // optional_REQUIRES_T(
+ // std::is_copy_constructible<U>::value
+ // || std11::is_trivially_copy_constructible<U>::value
+ // )
+ // >
+#endif
+ optional_constexpr14 optional( optional const & other )
+ : 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
+ template< typename U = T
+ optional_REQUIRES_T(
+ std11::is_move_constructible<U>::value
+ || std11::is_trivially_move_constructible<U>::value
+ )
+ >
+ optional_constexpr14 optional( optional && other )
+ // NOLINTNEXTLINE( performance-noexcept-move-constructor )
+ noexcept( std11::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
+ optional_REQUIRES_T(
+ 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 */
+ )
+ >
+ explicit optional( optional<U> const & other )
+ : 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
+#if optional_CPP11_OR_GREATER
+ optional_REQUIRES_T(
+ 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
+ >
+ // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions )
+ /*non-explicit*/ optional( optional<U> const & other )
+ : 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
+ optional_REQUIRES_T(
+ 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 */
+ )
+ >
+ explicit optional( optional<U> && other
+ )
+ : 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
+ optional_REQUIRES_T(
+ 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 */
+ )
+ >
+ // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions )
+ /*non-explicit*/ optional( optional<U> && other )
+ : 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( in_place, 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 = T
+ optional_REQUIRES_T(
+ 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 */
+ )
+ >
+ optional_constexpr explicit optional( U && value )
+ : has_value_( true )
+ , contained( nonstd_lite_in_place(T), std::forward<U>( value ) )
+ {}
+
+ // 8b (C++11) - non-explicit move construct from value
+ template< typename U = T
+ optional_REQUIRES_T(
+ 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 */
+ )
+ >
+ // NOLINTNEXTLINE( google-explicit-constructor, hicpp-explicit-conversions )
+ optional_constexpr /*non-explicit*/ optional( U && value )
+ : has_value_( true )
+ , contained( nonstd_lite_in_place(T), 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(
+ std11::is_nothrow_move_assignable<T>::value
+ && std11::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
+// std11::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
+ && std11::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
+ && std11::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
+ && !std11::is_assignable< T&, optional<U> & >::value
+ && !std11::is_assignable< T&, optional<U> && >::value
+ && !std11::is_assignable< T&, optional<U> const & >::value
+ && !std11::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
+ && std11::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
+ && !std11::is_assignable< T&, optional<U> & >::value
+ && !std11::is_assignable< T&, optional<U> && >::value
+ && !std11::is_assignable< T&, optional<U> const & >::value
+ && !std11::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(
+ std11::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_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_HAVE( REF_QUALIFIER )
+
+ 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
+ {
+#if optional_COMPILER_CLANG_VERSION
+ return has_value() ? /*std::move*/( contained.value() ) : static_cast<T>(std::forward<U>( v ) );
+#else
+ return has_value() ? std::move( contained.value() ) : static_cast<T>(std::forward<U>( v ) );
+#endif
+ }
+
+#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_HAVE( REF_QUALIFIER )
+
+#if !optional_CONFIG_NO_EXTENSIONS
+#if optional_HAVE( REF_QUALIFIER )
+
+ template< typename F >
+ optional_constexpr value_type value_or_eval( F f ) const &
+ {
+ return has_value() ? contained.value() : f();
+ }
+
+ template< typename F >
+ optional_constexpr14 value_type value_or_eval( F f ) &&
+ {
+ if ( has_value() )
+ {
+ return std::move( contained.value() );
+ }
+ else
+ {
+ return f();
+ }
+ }
+
+#else
+
+ template< typename F >
+ optional_constexpr value_type value_or_eval( F f ) const
+ {
+ return has_value() ? contained.value() : f();
+ }
+
+#endif // optional_HAVE( REF_QUALIFIER )
+#endif // !optional_CONFIG_NO_EXTENSIONS
+
+ // 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 >
+optional_nodiscard 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 >
+optional_nodiscard optional_constexpr bool operator!=( optional<T> const & x, optional<U> const & y )
+{
+ return !(x == y);
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<( optional<T> const & x, optional<U> const & y )
+{
+ return (!y) ? false : (!x) ? true : *x < *y;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator>( optional<T> const & x, optional<U> const & y )
+{
+ return (y < x);
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<=( optional<T> const & x, optional<U> const & y )
+{
+ return !(y < x);
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator>=( optional<T> const & x, optional<U> const & y )
+{
+ return !(x < y);
+}
+
+// Comparison with nullopt
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator==( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return (!x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator==( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept
+{
+ return (!x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator!=( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return bool(x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator!=( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept
+{
+ return bool(x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator<( optional<T> const & /*unused*/, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return false;
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator<( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept
+{
+ return bool(x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator<=( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return (!x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator<=( nullopt_t /*unused*/, optional<T> const & /*unused*/ ) optional_noexcept
+{
+ return true;
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator>( optional<T> const & x, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return bool(x);
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator>( nullopt_t /*unused*/, optional<T> const & /*unused*/ ) optional_noexcept
+{
+ return false;
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator>=( optional<T> const & /*unused*/, nullopt_t /*unused*/ ) optional_noexcept
+{
+ return true;
+}
+
+template< typename T >
+optional_nodiscard optional_constexpr bool operator>=( nullopt_t /*unused*/, optional<T> const & x ) optional_noexcept
+{
+ return (!x);
+}
+
+// Comparison with T
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator==( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x == v : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator==( U const & v, optional<T> const & x )
+{
+ return bool(x) ? v == *x : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator!=( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x != v : true;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator!=( U const & v, optional<T> const & x )
+{
+ return bool(x) ? v != *x : true;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x < v : true;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<( U const & v, optional<T> const & x )
+{
+ return bool(x) ? v < *x : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<=( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x <= v : true;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator<=( U const & v, optional<T> const & x )
+{
+ return bool(x) ? v <= *x : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator>( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x > v : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator>( U const & v, optional<T> const & x )
+{
+ return bool(x) ? v > *x : true;
+}
+
+template< typename T, typename U >
+optional_nodiscard optional_constexpr bool operator>=( optional<T> const & x, U const & v )
+{
+ return bool(x) ? *x >= v : false;
+}
+
+template< typename T, typename U >
+optional_nodiscard 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(
+ std11::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;
+
+#if ! optional_CONFIG_NO_EXCEPTIONS
+using optional_lite::bad_optional_access;
+#endif
+
+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
projects / lttng-tools.git / blobdiff