Current File : //backups/router/usr/local/include/boost/any/basic_any.hpp
// Copyright Ruslan Arutyunyan, 2019-2021.
// Copyright Antony Polukhin, 2021-2024.
//
// 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)
// Contributed by Ruslan Arutyunyan
#ifndef BOOST_ANYS_BASIC_ANY_HPP_INCLUDED
#define BOOST_ANYS_BASIC_ANY_HPP_INCLUDED
#include <boost/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
# pragma once
#endif
/// \file boost/any/basic_any.hpp
/// \brief \copybrief boost::anys::basic_any
#include <boost/any/bad_any_cast.hpp>
#include <boost/any/fwd.hpp>
#include <boost/assert.hpp>
#include <boost/type_index.hpp>
#include <boost/throw_exception.hpp>
#include <memory> // for std::addressof
#include <type_traits>
namespace boost {
namespace anys {
/// \brief A class with customizable Small Object Optimization whose
/// instances can hold instances of any type that satisfies
/// \forcedlink{ValueType} requirements. Use boost::any instead if not sure.
///
/// boost::anys::basic_any is the drop-in replacement for boost::any
/// that provides control over Small Object Optimization via
/// `OptimizeForSize` and `OptimizeForAlignment` template parameters.
///
/// There are certain applications that require boost::any
/// functionality, do know the typical/maximal size of the stored object and
/// wish to avoid dynamic memory allocation overhead. For the convenience
/// such applications may create a typedef for boost::anys::basic_any
/// with the `OptimizeForSize` and `OptimizeForAlignment` template
/// parameters set to typical/maximal size and alignment of types
/// respectively. Memory allocation would be avoided for storing nothrow
/// move constructible types with size and alignment less than or
/// equal to the `OptimizeForSize` and `OptimizeForAlignment` values.
///
/// Otherwise just use boost::any.
template <std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
class basic_any
{
static_assert(OptimizeForSize > 0 && OptimizeForAlignment > 0, "Size and Align shall be positive values");
static_assert(OptimizeForSize >= OptimizeForAlignment, "Size shall non less than Align");
static_assert((OptimizeForAlignment & (OptimizeForAlignment - 1)) == 0, "Align shall be a power of 2");
static_assert(OptimizeForSize % OptimizeForAlignment == 0, "Size shall be multiple of alignment");
private:
/// @cond
enum operation
{
Destroy,
Move,
Copy,
AnyCast,
UnsafeCast,
Typeinfo
};
template <typename ValueType>
static void* small_manager(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info)
{
switch (op)
{
case Destroy:
BOOST_ASSERT(!left.empty());
reinterpret_cast<ValueType*>(&left.content.small_value)->~ValueType();
break;
case Move: {
BOOST_ASSERT(left.empty());
BOOST_ASSERT(right);
BOOST_ASSERT(!right->empty());
BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
ValueType* value = reinterpret_cast<ValueType*>(&const_cast<basic_any*>(right)->content.small_value);
new (&left.content.small_value) ValueType(std::move(*value));
left.man = right->man;
reinterpret_cast<ValueType const*>(&right->content.small_value)->~ValueType();
const_cast<basic_any*>(right)->man = 0;
};
break;
case Copy:
BOOST_ASSERT(left.empty());
BOOST_ASSERT(right);
BOOST_ASSERT(!right->empty());
BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
new (&left.content.small_value) ValueType(*reinterpret_cast<const ValueType*>(&right->content.small_value));
left.man = right->man;
break;
case AnyCast:
BOOST_ASSERT(info);
BOOST_ASSERT(!left.empty());
return boost::typeindex::type_id<ValueType>() == *info ?
reinterpret_cast<typename std::remove_cv<ValueType>::type *>(&left.content.small_value) : 0;
case UnsafeCast:
BOOST_ASSERT(!left.empty());
return reinterpret_cast<typename std::remove_cv<ValueType>::type *>(&left.content.small_value);
case Typeinfo:
return const_cast<void*>(static_cast<const void*>(&boost::typeindex::type_id<ValueType>().type_info()));
}
return 0;
}
template <typename ValueType>
static void* large_manager(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info)
{
switch (op)
{
case Destroy:
BOOST_ASSERT(!left.empty());
delete static_cast<ValueType*>(left.content.large_value);
break;
case Move:
BOOST_ASSERT(left.empty());
BOOST_ASSERT(right);
BOOST_ASSERT(!right->empty());
BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
left.content.large_value = right->content.large_value;
left.man = right->man;
const_cast<basic_any*>(right)->content.large_value = 0;
const_cast<basic_any*>(right)->man = 0;
break;
case Copy:
BOOST_ASSERT(left.empty());
BOOST_ASSERT(right);
BOOST_ASSERT(!right->empty());
BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
left.content.large_value = new ValueType(*static_cast<const ValueType*>(right->content.large_value));
left.man = right->man;
break;
case AnyCast:
BOOST_ASSERT(info);
BOOST_ASSERT(!left.empty());
return boost::typeindex::type_id<ValueType>() == *info ?
static_cast<typename std::remove_cv<ValueType>::type *>(left.content.large_value) : 0;
case UnsafeCast:
BOOST_ASSERT(!left.empty());
return reinterpret_cast<typename std::remove_cv<ValueType>::type *>(left.content.large_value);
case Typeinfo:
return const_cast<void*>(static_cast<const void*>(&boost::typeindex::type_id<ValueType>().type_info()));
}
return 0;
}
template <typename ValueType>
struct is_small_object : std::integral_constant<bool, sizeof(ValueType) <= OptimizeForSize &&
alignof(ValueType) <= OptimizeForAlignment &&
std::is_nothrow_move_constructible<ValueType>::value>
{};
template <typename ValueType>
static void create(basic_any& any, const ValueType& value, std::true_type)
{
typedef typename std::decay<const ValueType>::type DecayedType;
any.man = &small_manager<DecayedType>;
new (&any.content.small_value) ValueType(value);
}
template <typename ValueType>
static void create(basic_any& any, const ValueType& value, std::false_type)
{
typedef typename std::decay<const ValueType>::type DecayedType;
any.man = &large_manager<DecayedType>;
any.content.large_value = new DecayedType(value);
}
template <typename ValueType>
static void create(basic_any& any, ValueType&& value, std::true_type)
{
typedef typename std::decay<const ValueType>::type DecayedType;
any.man = &small_manager<DecayedType>;
new (&any.content.small_value) DecayedType(std::forward<ValueType>(value));
}
template <typename ValueType>
static void create(basic_any& any, ValueType&& value, std::false_type)
{
typedef typename std::decay<const ValueType>::type DecayedType;
any.man = &large_manager<DecayedType>;
any.content.large_value = new DecayedType(std::forward<ValueType>(value));
}
/// @endcond
public: // non-type template parameters accessors
static constexpr std::size_t buffer_size = OptimizeForSize;
static constexpr std::size_t buffer_align = OptimizeForAlignment;
public: // structors
/// \post this->empty() is true.
constexpr basic_any() noexcept
: man(0), content()
{
}
/// Makes a copy of `value`, so
/// that the initial content of the new instance is equivalent
/// in both type and value to `value`.
///
/// Does not dynamically allocate if `ValueType` is nothrow
/// move constructible and `sizeof(value) <= OptimizeForSize` and
/// `alignof(value) <= OptimizeForAlignment`.
///
/// \throws std::bad_alloc or any exceptions arising from the copy
/// constructor of the contained type.
template<typename ValueType>
basic_any(const ValueType & value)
: man(0), content()
{
static_assert(
!std::is_same<ValueType, boost::any>::value,
"boost::anys::basic_any shall not be constructed from boost::any"
);
static_assert(
!anys::detail::is_basic_any<ValueType>::value,
"boost::anys::basic_any<A, B> shall not be constructed from boost::anys::basic_any<C, D>"
);
create(*this, value, is_small_object<ValueType>());
}
/// Copy constructor that copies content of
/// `other` into new instance, so that any content
/// is equivalent in both type and value to the content of
/// `other`, or empty if `other` is empty.
///
/// \throws May fail with a `std::bad_alloc`
/// exception or any exceptions arising from the copy
/// constructor of the contained type.
basic_any(const basic_any & other)
: man(0), content()
{
if (other.man)
{
other.man(Copy, *this, &other, 0);
}
}
/// Move constructor that moves content of
/// `other` into new instance and leaves `other` empty.
///
/// \post other->empty() is true
/// \throws Nothing.
basic_any(basic_any&& other) noexcept
: man(0), content()
{
if (other.man)
{
other.man(Move, *this, &other, 0);
}
}
/// Forwards `value`, so
/// that the initial content of the new instance is equivalent
/// in both type and value to `value` before the forward.
///
/// Does not dynamically allocate if `ValueType` is nothrow
/// move constructible and `sizeof(value) <= OptimizeForSize` and
/// `alignof(value) <= OptimizeForAlignment`.
///
/// \throws std::bad_alloc or any exceptions arising from the move or
/// copy constructor of the contained type.
template<typename ValueType>
basic_any(ValueType&& value
, typename std::enable_if<!std::is_same<basic_any&, ValueType>::value >::type* = 0 // disable if value has type `basic_any&`
, typename std::enable_if<!std::is_const<ValueType>::value >::type* = 0) // disable if value has type `const ValueType&&`
: man(0), content()
{
typedef typename std::decay<ValueType>::type DecayedType;
static_assert(
!std::is_same<DecayedType, boost::any>::value,
"boost::anys::basic_any shall not be constructed from boost::any"
);
static_assert(
!anys::detail::is_basic_any<DecayedType>::value,
"boost::anys::basic_any<A, B> shall not be constructed from boost::anys::basic_any<C, D>"
);
create(*this, static_cast<ValueType&&>(value), is_small_object<DecayedType>());
}
/// Releases any and all resources used in management of instance.
///
/// \throws Nothing.
~basic_any() noexcept
{
if (man)
{
man(Destroy, *this, 0, 0);
}
}
public: // modifiers
/// Exchange of the contents of `*this` and `rhs`.
///
/// \returns `*this`
/// \throws Nothing.
basic_any & swap(basic_any & rhs) noexcept
{
if (this == &rhs)
{
return *this;
}
if (man && rhs.man)
{
basic_any tmp;
rhs.man(Move, tmp, &rhs, 0);
man(Move, rhs, this, 0);
tmp.man(Move, *this, &tmp, 0);
}
else if (man)
{
man(Move, rhs, this, 0);
}
else if (rhs.man)
{
rhs.man(Move, *this, &rhs, 0);
}
return *this;
}
/// Copies content of `rhs` into
/// current instance, discarding previous content, so that the
/// new content is equivalent in both type and value to the
/// content of `rhs`, or empty if `rhs.empty()`.
///
/// \throws std::bad_alloc
/// or any exceptions arising from the copy constructor of the
/// contained type. Assignment satisfies the strong guarantee
/// of exception safety.
basic_any & operator=(const basic_any& rhs)
{
basic_any(rhs).swap(*this);
return *this;
}
/// Moves content of `rhs` into
/// current instance, discarding previous content, so that the
/// new content is equivalent in both type and value to the
/// content of `rhs` before move, or empty if
/// `rhs.empty()`.
///
/// \post `rhs->empty()` is true
/// \throws Nothing.
basic_any & operator=(basic_any&& rhs) noexcept
{
rhs.swap(*this);
basic_any().swap(rhs);
return *this;
}
/// Forwards `rhs`,
/// discarding previous content, so that the new content of is
/// equivalent in both type and value to
/// `rhs` before forward.
///
/// Does not dynamically allocate if `ValueType` is nothrow
/// move constructible and `sizeof(value) <= OptimizeForSize` and
/// `alignof(value) <= OptimizeForAlignment`.
///
/// \throws std::bad_alloc
/// or any exceptions arising from the move or copy constructor of the
/// contained type. Assignment satisfies the strong guarantee
/// of exception safety.
template <class ValueType>
basic_any & operator=(ValueType&& rhs)
{
typedef typename std::decay<ValueType>::type DecayedType;
static_assert(
!std::is_same<DecayedType, boost::any>::value,
"boost::any shall not be assigned into boost::anys::basic_any"
);
static_assert(
!anys::detail::is_basic_any<DecayedType>::value || std::is_same<DecayedType, basic_any>::value,
"boost::anys::basic_any<A, B> shall not be assigned into boost::anys::basic_any<C, D>"
);
basic_any(std::forward<ValueType>(rhs)).swap(*this);
return *this;
}
public: // queries
/// \returns `true` if instance is empty, otherwise `false`.
/// \throws Nothing.
bool empty() const noexcept
{
return !man;
}
/// \post this->empty() is true
void clear() noexcept
{
basic_any().swap(*this);
}
/// \returns the `typeid` of the
/// contained value if instance is non-empty, otherwise
/// `typeid(void)`.
///
/// Useful for querying against types known either at compile time or
/// only at runtime.
const boost::typeindex::type_info& type() const BOOST_NOEXCEPT
{
return man
? *static_cast<const boost::typeindex::type_info*>(man(Typeinfo, const_cast<basic_any&>(*this), 0, 0))
: boost::typeindex::type_id<void>().type_info();
}
private: // representation
/// @cond
template<typename ValueType, std::size_t Size, std::size_t Alignment>
friend ValueType * any_cast(basic_any<Size, Alignment> *) noexcept;
template<typename ValueType, std::size_t Size, std::size_t Alignment>
friend ValueType * unsafe_any_cast(basic_any<Size, Alignment> *) noexcept;
typedef void*(*manager)(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info);
manager man;
union content {
void * large_value;
alignas(OptimizeForAlignment) unsigned char small_value[OptimizeForSize];
} content;
/// @endcond
};
/// Exchange of the contents of `lhs` and `rhs`.
/// \throws Nothing.
template<std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
void swap(basic_any<OptimizeForSize, OptimizeForAlignment>& lhs, basic_any<OptimizeForSize, OptimizeForAlignment>& rhs) noexcept
{
lhs.swap(rhs);
}
/// \returns Pointer to a ValueType stored in `operand`, nullptr if
/// `operand` does not contain specified `ValueType`.
template<typename ValueType, std::size_t Size, std::size_t Alignment>
ValueType * any_cast(basic_any<Size, Alignment> * operand) noexcept
{
return operand->man ?
static_cast<typename std::remove_cv<ValueType>::type *>(operand->man(basic_any<Size, Alignment>::AnyCast, *operand, 0, &boost::typeindex::type_id<ValueType>().type_info()))
: 0;
}
/// \returns Const pointer to a ValueType stored in `operand`, nullptr if
/// `operand` does not contain specified `ValueType`.
template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
inline const ValueType * any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> * operand) noexcept
{
return boost::anys::any_cast<ValueType>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> *>(operand));
}
/// \returns ValueType stored in `operand`
/// \throws boost::bad_any_cast if `operand` does not contain
/// specified ValueType.
template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
ValueType any_cast(basic_any<OptimizeForSize, OptimizeForAlignment> & operand)
{
typedef typename std::remove_reference<ValueType>::type nonref;
nonref * result = boost::anys::any_cast<nonref>(std::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 typename std::conditional<
std::is_reference<ValueType>::value,
ValueType,
typename std::add_lvalue_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
}
/// \returns `ValueType` stored in `operand`
/// \throws boost::bad_any_cast if `operand` does not contain
/// specified `ValueType`.
template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
inline ValueType any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> & operand)
{
typedef typename std::remove_reference<ValueType>::type nonref;
return boost::anys::any_cast<const nonref &>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> &>(operand));
}
/// \returns `ValueType` stored in `operand`, leaving the `operand` empty.
/// \throws boost::bad_any_cast if `operand` does not contain
/// specified `ValueType`.
template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
inline ValueType any_cast(basic_any<OptimizeForSize, OptimizeForAlignment>&& operand)
{
static_assert(
std::is_rvalue_reference<ValueType&&>::value /*true if ValueType is rvalue or just a value*/
|| std::is_const< typename std::remove_reference<ValueType>::type >::value,
"boost::any_cast shall not be used for getting nonconst references to temporary objects"
);
return boost::anys::any_cast<ValueType>(operand);
}
/// @cond
// 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, std::size_t OptimizedForSize, std::size_t OptimizeForAlignment>
inline ValueType * unsafe_any_cast(basic_any<OptimizedForSize, OptimizeForAlignment> * operand) noexcept
{
return static_cast<ValueType*>(operand->man(basic_any<OptimizedForSize, OptimizeForAlignment>::UnsafeCast, *operand, 0, 0));
}
template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
inline const ValueType * unsafe_any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> * operand) noexcept
{
return boost::anys::unsafe_any_cast<ValueType>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> *>(operand));
}
/// @endcond
} // namespace anys
using boost::anys::any_cast;
using boost::anys::unsafe_any_cast;
} // namespace boost
#endif // #ifndef BOOST_ANYS_BASIC_ANY_HPP_INCLUDED
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