boost/any.hpp
// See http://www.boost.org/libs/any for Documentation.
#ifndef BOOST_ANY_INCLUDED
#define BOOST_ANY_INCLUDED
#include <boost/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
# pragma once
#endif
// what: variant type boost::any
// who: contributed by Kevlin Henney,
// with features contributed and bugs found by
// Antony Polukhin, Ed Brey, Mark Rodgers,
// Peter Dimov, and James Curran
// when: July 2001, April 2013 - 2020
#include <boost/any/bad_any_cast.hpp>
#include <boost/any/fwd.hpp>
#include <boost/type_index.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/decay.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/throw_exception.hpp>
#include <boost/static_assert.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/core/addressof.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/conditional.hpp>
namespace boost
{
class any
{
public: // structors
BOOST_CONSTEXPR any() BOOST_NOEXCEPT
: content(0)
{
}
template<typename ValueType>
any(const ValueType & value)
: content(new holder<
BOOST_DEDUCED_TYPENAME remove_cv<BOOST_DEDUCED_TYPENAME decay<const ValueType>::type>::type
>(value))
{
BOOST_STATIC_ASSERT_MSG(
!anys::detail::is_basic_any<ValueType>::value,
"boost::any shall not be constructed from boost::anys::basic_any"
);
}
any(const any & other)
: content(other.content ? other.content->clone() : 0)
{
}
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
// Move constructor
any(any&& other) BOOST_NOEXCEPT
: content(other.content)
{
other.content = 0;
}
// Perfect forwarding of ValueType
template<typename ValueType>
any(ValueType&& value
, typename boost::disable_if<boost::is_same<any&, ValueType> >::type* = 0 // disable if value has type `any&`
, typename boost::disable_if<boost::is_const<ValueType> >::type* = 0) // disable if value has type `const ValueType&&`
: content(new holder< typename decay<ValueType>::type >(static_cast<ValueType&&>(value)))
{
BOOST_STATIC_ASSERT_MSG(
!anys::detail::is_basic_any<typename boost::decay<ValueType>::type>::value,
"boost::any shall not be constructed from boost::anys::basic_any"
);
}
#endif
~any() BOOST_NOEXCEPT
{
delete content;
}
public: // modifiers
any & swap(any & rhs) BOOST_NOEXCEPT
{
placeholder* tmp = content;
content = rhs.content;
rhs.content = tmp;
return *this;
}
#ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
template<typename ValueType>
any & operator=(const ValueType & rhs)
{
BOOST_STATIC_ASSERT_MSG(
!anys::detail::is_basic_any<ValueType>::value,
"boost::anys::basic_any shall not be assigned into boost::any"
);
any(rhs).swap(*this);
return *this;
}
any & operator=(any rhs)
{
rhs.swap(*this);
return *this;
}
#else
any & operator=(const any& rhs)
{
any(rhs).swap(*this);
return *this;
}
// move assignment
any & operator=(any&& rhs) BOOST_NOEXCEPT
{
rhs.swap(*this);
any().swap(rhs);
return *this;
}
// Perfect forwarding of ValueType
template <class ValueType>
any & operator=(ValueType&& rhs)
{
BOOST_STATIC_ASSERT_MSG(
!anys::detail::is_basic_any<typename boost::decay<ValueType>::type>::value,
"boost::anys::basic_any shall not be assigned into boost::any"
);
any(static_cast<ValueType&&>(rhs)).swap(*this);
return *this;
}
#endif
public: // queries
bool empty() const BOOST_NOEXCEPT
{
return !content;
}
void clear() BOOST_NOEXCEPT
{
any().swap(*this);
}
const boost::typeindex::type_info& type() const BOOST_NOEXCEPT
{
return content ? content->type() : boost::typeindex::type_id<void>().type_info();
}
#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
private: // types
#else
public: // types (public so any_cast can be non-friend)
#endif
class BOOST_SYMBOL_VISIBLE placeholder
{
public: // structors
virtual ~placeholder()
{
}
public: // queries
virtual const boost::typeindex::type_info& type() const BOOST_NOEXCEPT = 0;
virtual placeholder * clone() const = 0;
};
template<typename ValueType>
class holder
#ifndef BOOST_NO_CXX11_FINAL
final
#endif
: public placeholder
{
public: // structors
holder(const ValueType & value)
: held(value)
{
}
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
holder(ValueType&& value)
: held(static_cast< ValueType&& >(value))
{
}
#endif
public: // queries
const boost::typeindex::type_info& type() const BOOST_NOEXCEPT BOOST_OVERRIDE
{
return boost::typeindex::type_id<ValueType>().type_info();
}
placeholder * clone() const BOOST_OVERRIDE
{
return new holder(held);
}
public: // representation
ValueType held;
private: // intentionally left unimplemented
holder & operator=(const holder &);
};
#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
private: // representation
template<typename ValueType>
friend ValueType * any_cast(any *) BOOST_NOEXCEPT;
template<typename ValueType>
friend ValueType * unsafe_any_cast(any *) BOOST_NOEXCEPT;
#else
public: // representation (public so any_cast can be non-friend)
#endif
placeholder * content;
};
inline void swap(any & lhs, any & rhs) BOOST_NOEXCEPT
{
lhs.swap(rhs);
}
template<typename ValueType>
ValueType * any_cast(any * operand) BOOST_NOEXCEPT
{
return operand && operand->type() == boost::typeindex::type_id<ValueType>()
? boost::addressof(
static_cast<any::holder<BOOST_DEDUCED_TYPENAME remove_cv<ValueType>::type> *>(operand->content)->held
)
: 0;
}
template<typename ValueType>
inline const ValueType * any_cast(const any * operand) BOOST_NOEXCEPT
{
return any_cast<ValueType>(const_cast<any *>(operand));
}
template<typename ValueType>
ValueType any_cast(any & operand)
{
typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
nonref * result = any_cast<nonref>(boost::addressof(operand));
if(!result)
boost::throw_exception(bad_any_cast());
// Attempt to avoid construction of a temporary object in cases when
// `ValueType` is not a reference. Example:
// `static_cast<std::string>(*result);`
// which is equal to `std::string(*result);`
typedef BOOST_DEDUCED_TYPENAME boost::conditional<
boost::is_reference<ValueType>::value,
ValueType,
BOOST_DEDUCED_TYPENAME boost::add_reference<ValueType>::type
>::type ref_type;
#ifdef BOOST_MSVC
# pragma warning(push)
# pragma warning(disable: 4172) // "returning address of local variable or temporary" but *result is not local!
#endif
return static_cast<ref_type>(*result);
#ifdef BOOST_MSVC
# pragma warning(pop)
#endif
}
template<typename ValueType>
inline ValueType any_cast(const any & operand)
{
typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref;
return any_cast<const nonref &>(const_cast<any &>(operand));
}
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
template<typename ValueType>
inline ValueType any_cast(any&& operand)
{
BOOST_STATIC_ASSERT_MSG(
boost::is_rvalue_reference<ValueType&&>::value /*true if ValueType is rvalue or just a value*/
|| boost::is_const< typename boost::remove_reference<ValueType>::type >::value,
"boost::any_cast shall not be used for getting nonconst references to temporary objects"
);
return any_cast<ValueType>(operand);
}
#endif
// Note: The "unsafe" versions of any_cast are not part of the
// public interface and may be removed at any time. They are
// required where we know what type is stored in the any and can't
// use typeid() comparison, e.g., when our types may travel across
// different shared libraries.
template<typename ValueType>
inline ValueType * unsafe_any_cast(any * operand) BOOST_NOEXCEPT
{
return boost::addressof(
static_cast<any::holder<ValueType> *>(operand->content)->held
);
}
template<typename ValueType>
inline const ValueType * unsafe_any_cast(const any * operand) BOOST_NOEXCEPT
{
return unsafe_any_cast<ValueType>(const_cast<any *>(operand));
}
}
// Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved.
// Copyright Antony Polukhin, 2013-2022.
//
// 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)
#endif