mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-21 12:21:31 +03:00
345 lines
11 KiB
C++
345 lines
11 KiB
C++
//-----------------------------------------------------------------------------
|
|
// boost variant/polymorphic_get.hpp header file
|
|
// See http://www.boost.org for updates, documentation, and revision history.
|
|
//-----------------------------------------------------------------------------
|
|
//
|
|
// Copyright (c) 2013-2015 Antony Polukhin
|
|
//
|
|
// Distributed under the Boost Software License, Version 1.0. (See
|
|
// accompanying file LICENSE_1_0.txt or copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
|
|
#ifndef BOOST_VARIANT_POLYMORPHIC_GET_HPP
|
|
#define BOOST_VARIANT_POLYMORPHIC_GET_HPP
|
|
|
|
#include <exception>
|
|
|
|
#include <boost/config.hpp>
|
|
#include <boost/detail/workaround.hpp>
|
|
#include <boost/static_assert.hpp>
|
|
#include <boost/throw_exception.hpp>
|
|
#include <boost/utility/addressof.hpp>
|
|
#include <boost/variant/variant_fwd.hpp>
|
|
#include <boost/variant/get.hpp>
|
|
|
|
#include <boost/type_traits/add_reference.hpp>
|
|
#include <boost/type_traits/add_pointer.hpp>
|
|
#include <boost/type_traits/is_base_of.hpp>
|
|
|
|
namespace boost {
|
|
|
|
//////////////////////////////////////////////////////////////////////////
|
|
// class bad_polymorphic_get
|
|
//
|
|
// The exception thrown in the event of a failed get of a value.
|
|
//
|
|
class BOOST_SYMBOL_VISIBLE bad_polymorphic_get
|
|
: public bad_get
|
|
{
|
|
public: // std::exception implementation
|
|
|
|
virtual const char * what() const BOOST_NOEXCEPT_OR_NOTHROW
|
|
{
|
|
return "boost::bad_polymorphic_get: "
|
|
"failed value get using boost::polymorphic_get";
|
|
}
|
|
|
|
};
|
|
|
|
//////////////////////////////////////////////////////////////////////////
|
|
// function template get<T>
|
|
//
|
|
// Retrieves content of given variant object if content is of type T.
|
|
// Otherwise: pointer ver. returns 0; reference ver. throws bad_get.
|
|
//
|
|
|
|
namespace detail { namespace variant {
|
|
|
|
|
|
///////////////////////////////////////////////////////////////////////////////////////////////////
|
|
// polymorphic metafunctions to detect index of a value
|
|
//
|
|
|
|
template <class Types, class T>
|
|
struct element_polymorphic_iterator_impl :
|
|
boost::mpl::find_if<
|
|
Types,
|
|
boost::mpl::or_<
|
|
variant_element_functor<boost::mpl::_1, T>,
|
|
variant_element_functor<boost::mpl::_1, typename boost::remove_cv<T>::type >,
|
|
boost::is_base_of<T, boost::mpl::_1>
|
|
>
|
|
>
|
|
{};
|
|
|
|
template <class Variant, class T>
|
|
struct holds_element_polymorphic :
|
|
boost::mpl::not_<
|
|
boost::is_same<
|
|
typename boost::mpl::end<typename Variant::types>::type,
|
|
typename element_polymorphic_iterator_impl<typename Variant::types, typename boost::remove_reference<T>::type >::type
|
|
>
|
|
>
|
|
{};
|
|
|
|
// (detail) class template get_polymorphic_visitor
|
|
//
|
|
// Generic static visitor that: if the value is of the specified
|
|
// type or of a type derived from specified, returns a pointer
|
|
// to the value it visits; else a null pointer.
|
|
//
|
|
template <typename Base>
|
|
struct get_polymorphic_visitor
|
|
{
|
|
private: // private typedefs
|
|
typedef get_polymorphic_visitor<Base> this_type;
|
|
typedef typename add_pointer<Base>::type pointer;
|
|
typedef typename add_reference<Base>::type reference;
|
|
|
|
pointer get(reference operand, boost::true_type) const BOOST_NOEXCEPT
|
|
{
|
|
return boost::addressof(operand);
|
|
}
|
|
|
|
template <class T>
|
|
pointer get(T&, boost::false_type) const BOOST_NOEXCEPT
|
|
{
|
|
return static_cast<pointer>(0);
|
|
}
|
|
|
|
public: // visitor interfaces
|
|
typedef pointer result_type;
|
|
|
|
template <typename U>
|
|
pointer operator()(U& operand) const BOOST_NOEXCEPT
|
|
{
|
|
typedef boost::integral_constant<
|
|
bool,
|
|
boost::mpl::or_<
|
|
boost::is_base_of<Base, U>,
|
|
boost::is_same<Base, U>,
|
|
boost::is_same<typename boost::remove_cv<Base>::type, U >
|
|
>::value
|
|
> tag_t;
|
|
|
|
return this_type::get(operand, tag_t());
|
|
}
|
|
};
|
|
|
|
}} // namespace detail::variant
|
|
|
|
#ifndef BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE
|
|
# if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551))
|
|
# define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t)
|
|
# else
|
|
# define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t) \
|
|
, t* = 0
|
|
# endif
|
|
#endif
|
|
|
|
//////////////////////////////////////////////////////////////////////////////////////////////////////////
|
|
// polymorphic_relaxed_get
|
|
//
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<U>::type
|
|
polymorphic_relaxed_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
typedef typename add_pointer<U>::type U_ptr;
|
|
if (!operand) return static_cast<U_ptr>(0);
|
|
|
|
detail::variant::get_polymorphic_visitor<U> v;
|
|
return operand->apply_visitor(v);
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<const U>::type
|
|
polymorphic_relaxed_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
typedef typename add_pointer<const U>::type U_ptr;
|
|
if (!operand) return static_cast<U_ptr>(0);
|
|
|
|
detail::variant::get_polymorphic_visitor<const U> v;
|
|
return operand->apply_visitor(v);
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<U>::type
|
|
polymorphic_relaxed_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
typedef typename add_pointer<U>::type U_ptr;
|
|
U_ptr result = polymorphic_relaxed_get<U>(&operand);
|
|
|
|
if (!result)
|
|
boost::throw_exception(bad_polymorphic_get());
|
|
return *result;
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<const U>::type
|
|
polymorphic_relaxed_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
typedef typename add_pointer<const U>::type U_ptr;
|
|
U_ptr result = polymorphic_relaxed_get<const U>(&operand);
|
|
|
|
if (!result)
|
|
boost::throw_exception(bad_polymorphic_get());
|
|
return *result;
|
|
}
|
|
|
|
//////////////////////////////////////////////////////////////////////////////////////////////////////////
|
|
// polymorphic_strict_get
|
|
//
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<U>::type
|
|
polymorphic_strict_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
BOOST_STATIC_ASSERT_MSG(
|
|
(boost::detail::variant::holds_element_polymorphic<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
|
|
"boost::variant does not contain specified type U, "
|
|
"call to boost::polymorphic_get<U>(boost::variant<T...>*) will always return NULL"
|
|
);
|
|
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<const U>::type
|
|
polymorphic_strict_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
BOOST_STATIC_ASSERT_MSG(
|
|
(boost::detail::variant::holds_element_polymorphic<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
|
|
"boost::variant does not contain specified type U, "
|
|
"call to boost::polymorphic_get<U>(const boost::variant<T...>*) will always return NULL"
|
|
);
|
|
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<U>::type
|
|
polymorphic_strict_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
BOOST_STATIC_ASSERT_MSG(
|
|
(boost::detail::variant::holds_element_polymorphic<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
|
|
"boost::variant does not contain specified type U, "
|
|
"call to boost::polymorphic_get<U>(boost::variant<T...>&) will always throw boost::bad_polymorphic_get exception"
|
|
);
|
|
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<const U>::type
|
|
polymorphic_strict_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
BOOST_STATIC_ASSERT_MSG(
|
|
(boost::detail::variant::holds_element_polymorphic<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
|
|
"boost::variant does not contain specified type U, "
|
|
"call to boost::polymorphic_get<U>(const boost::variant<T...>&) will always throw boost::bad_polymorphic_get exception"
|
|
);
|
|
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
}
|
|
|
|
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
|
// polymorphic_get<U>(variant) methods
|
|
//
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<U>::type
|
|
polymorphic_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
#else
|
|
return polymorphic_strict_get<U>(operand);
|
|
#endif
|
|
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_pointer<const U>::type
|
|
polymorphic_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
) BOOST_NOEXCEPT
|
|
{
|
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
#else
|
|
return polymorphic_strict_get<U>(operand);
|
|
#endif
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<U>::type
|
|
polymorphic_get(
|
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
#else
|
|
return polymorphic_strict_get<U>(operand);
|
|
#endif
|
|
}
|
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
|
|
inline
|
|
typename add_reference<const U>::type
|
|
polymorphic_get(
|
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
|
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
|
|
)
|
|
{
|
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
|
|
return polymorphic_relaxed_get<U>(operand);
|
|
#else
|
|
return polymorphic_strict_get<U>(operand);
|
|
#endif
|
|
}
|
|
} // namespace boost
|
|
|
|
#endif // BOOST_VARIANT_POLYMORPHIC_GET_HPP
|