You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
273 lines
10 KiB
273 lines
10 KiB
// Copyright (C) 2015-2018 Andrzej Krzemienski.
|
|
//
|
|
// Use, modification, and distribution is subject to 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)
|
|
//
|
|
// See http://www.boost.org/libs/optional for documentation.
|
|
//
|
|
// You are welcome to contact the author at:
|
|
// akrzemi1@gmail.com
|
|
|
|
#ifndef BOOST_OPTIONAL_DETAIL_OPTIONAL_REFERENCE_SPEC_AJK_03OCT2015_HPP
|
|
#define BOOST_OPTIONAL_DETAIL_OPTIONAL_REFERENCE_SPEC_AJK_03OCT2015_HPP
|
|
|
|
#ifdef BOOST_OPTIONAL_CONFIG_NO_PROPER_ASSIGN_FROM_CONST_INT
|
|
#include <boost/type_traits/is_integral.hpp>
|
|
#include <boost/type_traits/is_const.hpp>
|
|
#endif
|
|
|
|
# if 1
|
|
|
|
namespace boost {
|
|
|
|
namespace detail {
|
|
|
|
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
|
|
|
|
template <class From>
|
|
void prevent_binding_rvalue()
|
|
{
|
|
#ifndef BOOST_OPTIONAL_CONFIG_ALLOW_BINDING_TO_RVALUES
|
|
BOOST_STATIC_ASSERT_MSG(boost::is_lvalue_reference<From>::value,
|
|
"binding rvalue references to optional lvalue references is disallowed");
|
|
#endif
|
|
}
|
|
|
|
template <class T>
|
|
BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type& forward_reference(T&& r)
|
|
{
|
|
BOOST_STATIC_ASSERT_MSG(boost::is_lvalue_reference<T>::value,
|
|
"binding rvalue references to optional lvalue references is disallowed");
|
|
return boost::forward<T>(r);
|
|
}
|
|
|
|
#endif // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
|
|
|
|
|
|
template <class T>
|
|
struct is_const_integral
|
|
{
|
|
static const bool value = boost::is_const<T>::value && boost::is_integral<T>::value;
|
|
};
|
|
|
|
template <class T>
|
|
struct is_const_integral_bad_for_conversion
|
|
{
|
|
#if (!defined BOOST_OPTIONAL_CONFIG_ALLOW_BINDING_TO_RVALUES) && (defined BOOST_OPTIONAL_CONFIG_NO_PROPER_CONVERT_FROM_CONST_INT)
|
|
static const bool value = boost::is_const<T>::value && boost::is_integral<T>::value;
|
|
#else
|
|
static const bool value = false;
|
|
#endif
|
|
};
|
|
|
|
template <class From>
|
|
void prevent_assignment_from_false_const_integral()
|
|
{
|
|
#ifndef BOOST_OPTIONAL_CONFIG_ALLOW_BINDING_TO_RVALUES
|
|
#ifdef BOOST_OPTIONAL_CONFIG_NO_PROPER_ASSIGN_FROM_CONST_INT
|
|
// MSVC compiler without rvalue refernces: we need to disable the asignment from
|
|
// const integral lvalue reference, as it may be an invalid temporary
|
|
BOOST_STATIC_ASSERT_MSG(!is_const_integral<From>::value,
|
|
"binding const lvalue references to integral types is disabled in this compiler");
|
|
#endif
|
|
#endif
|
|
}
|
|
|
|
|
|
template <class T>
|
|
struct is_optional_
|
|
{
|
|
static const bool value = false;
|
|
};
|
|
|
|
template <class U>
|
|
struct is_optional_< ::boost::optional<U> >
|
|
{
|
|
static const bool value = true;
|
|
};
|
|
|
|
template <class T>
|
|
struct is_no_optional
|
|
{
|
|
static const bool value = !is_optional_<BOOST_DEDUCED_TYPENAME boost::decay<T>::type>::value;
|
|
};
|
|
|
|
|
|
template <class T, class U>
|
|
struct is_same_decayed
|
|
{
|
|
static const bool value = ::boost::is_same<T, BOOST_DEDUCED_TYPENAME ::boost::remove_reference<U>::type>::value
|
|
|| ::boost::is_same<T, const BOOST_DEDUCED_TYPENAME ::boost::remove_reference<U>::type>::value;
|
|
};
|
|
|
|
template <class T, class U>
|
|
struct no_unboxing_cond
|
|
{
|
|
static const bool value = is_no_optional<U>::value && !is_same_decayed<T, U>::value;
|
|
};
|
|
|
|
|
|
} // namespace detail
|
|
|
|
template <class T>
|
|
class optional<T&> : public optional_detail::optional_tag
|
|
{
|
|
T* ptr_;
|
|
|
|
public:
|
|
typedef T& value_type;
|
|
typedef T& reference_type;
|
|
typedef T& reference_const_type;
|
|
typedef T& rval_reference_type;
|
|
typedef T* pointer_type;
|
|
typedef T* pointer_const_type;
|
|
|
|
optional() BOOST_NOEXCEPT : ptr_() {}
|
|
optional(none_t) BOOST_NOEXCEPT : ptr_() {}
|
|
|
|
template <class U>
|
|
explicit optional(const optional<U&>& rhs) BOOST_NOEXCEPT : ptr_(rhs.get_ptr()) {}
|
|
optional(const optional& rhs) BOOST_NOEXCEPT : ptr_(rhs.get_ptr()) {}
|
|
|
|
// the following two implement a 'conditionally explicit' constructor: condition is a hack for buggy compilers with srewed conversion construction from const int
|
|
template <class U>
|
|
explicit optional(U& rhs, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::is_same_decayed<T, U>::value && detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(boost::addressof(rhs)) {}
|
|
|
|
template <class U>
|
|
optional(U& rhs, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::is_same_decayed<T, U>::value && !detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(boost::addressof(rhs)) {}
|
|
|
|
optional& operator=(const optional& rhs) BOOST_NOEXCEPT { ptr_ = rhs.get_ptr(); return *this; }
|
|
template <class U>
|
|
optional& operator=(const optional<U&>& rhs) BOOST_NOEXCEPT { ptr_ = rhs.get_ptr(); return *this; }
|
|
optional& operator=(none_t) BOOST_NOEXCEPT { ptr_ = 0; return *this; }
|
|
|
|
|
|
void swap(optional& rhs) BOOST_NOEXCEPT { std::swap(ptr_, rhs.ptr_); }
|
|
T& get() const { BOOST_ASSERT(ptr_); return *ptr_; }
|
|
|
|
T* get_ptr() const BOOST_NOEXCEPT { return ptr_; }
|
|
T* operator->() const { BOOST_ASSERT(ptr_); return ptr_; }
|
|
T& operator*() const { BOOST_ASSERT(ptr_); return *ptr_; }
|
|
T& value() const { return ptr_ ? *ptr_ : (throw_exception(bad_optional_access()), *ptr_); }
|
|
|
|
bool operator!() const BOOST_NOEXCEPT { return ptr_ == 0; }
|
|
BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
|
|
|
|
void reset() BOOST_NOEXCEPT { ptr_ = 0; }
|
|
|
|
bool is_initialized() const BOOST_NOEXCEPT { return ptr_ != 0; }
|
|
bool has_value() const BOOST_NOEXCEPT { return ptr_ != 0; }
|
|
|
|
template <typename F>
|
|
optional<typename boost::result_of<F(T&)>::type> map(F f) const
|
|
{
|
|
if (this->has_value())
|
|
return f(this->get());
|
|
else
|
|
return none;
|
|
}
|
|
|
|
template <typename F>
|
|
optional<typename optional_detail::optional_value_type<typename boost::result_of<F(T&)>::type>::type> flat_map(F f) const
|
|
{
|
|
if (this->has_value())
|
|
return f(get());
|
|
else
|
|
return none;
|
|
}
|
|
|
|
#ifndef BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
|
|
|
|
optional(T&& /* rhs */) BOOST_NOEXCEPT { detail::prevent_binding_rvalue<T&&>(); }
|
|
|
|
template <class R>
|
|
optional(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::no_unboxing_cond<T, R>, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(boost::addressof(r)) { detail::prevent_binding_rvalue<R>(); }
|
|
|
|
template <class R>
|
|
optional(bool cond, R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(cond ? boost::addressof(r) : 0) { detail::prevent_binding_rvalue<R>(); }
|
|
|
|
template <class R>
|
|
BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, optional<T&>&>::type
|
|
operator=(R&& r) BOOST_NOEXCEPT { detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); return *this; }
|
|
|
|
template <class R>
|
|
void emplace(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
|
|
{ detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); }
|
|
|
|
template <class R>
|
|
T& get_value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) const BOOST_NOEXCEPT
|
|
{ detail::prevent_binding_rvalue<R>(); return ptr_ ? *ptr_ : r; }
|
|
|
|
template <class R>
|
|
T& value_or(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) const BOOST_NOEXCEPT
|
|
{ detail::prevent_binding_rvalue<R>(); return ptr_ ? *ptr_ : r; }
|
|
|
|
template <class R>
|
|
void reset(R&& r, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<R>, bool>::type = true) BOOST_NOEXCEPT
|
|
{ detail::prevent_binding_rvalue<R>(); ptr_ = boost::addressof(r); }
|
|
|
|
template <class F>
|
|
T& value_or_eval(F f) const { return ptr_ ? *ptr_ : detail::forward_reference(f()); }
|
|
|
|
#else // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
|
|
|
|
|
|
// the following two implement a 'conditionally explicit' constructor
|
|
template <class U>
|
|
explicit optional(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::no_unboxing_cond<T, U>::value && detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(boost::addressof(v)) { }
|
|
|
|
template <class U>
|
|
optional(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if_c<detail::no_unboxing_cond<T, U>::value && !detail::is_const_integral_bad_for_conversion<U>::value, bool>::type = true) BOOST_NOEXCEPT
|
|
: ptr_(boost::addressof(v)) { }
|
|
|
|
template <class U>
|
|
optional(bool cond, U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT : ptr_(cond ? boost::addressof(v) : 0) {}
|
|
|
|
template <class U>
|
|
BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, optional<T&>&>::type
|
|
operator=(U& v) BOOST_NOEXCEPT
|
|
{
|
|
detail::prevent_assignment_from_false_const_integral<U>();
|
|
ptr_ = boost::addressof(v); return *this;
|
|
}
|
|
|
|
template <class U>
|
|
void emplace(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT
|
|
{ ptr_ = boost::addressof(v); }
|
|
|
|
template <class U>
|
|
T& get_value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) const BOOST_NOEXCEPT
|
|
{ return ptr_ ? *ptr_ : v; }
|
|
|
|
template <class U>
|
|
T& value_or(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) const BOOST_NOEXCEPT
|
|
{ return ptr_ ? *ptr_ : v; }
|
|
|
|
template <class U>
|
|
void reset(U& v, BOOST_DEDUCED_TYPENAME boost::enable_if<detail::is_no_optional<U>, bool>::type = true) BOOST_NOEXCEPT
|
|
{ ptr_ = boost::addressof(v); }
|
|
|
|
template <class F>
|
|
T& value_or_eval(F f) const { return ptr_ ? *ptr_ : f(); }
|
|
|
|
#endif // BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
|
|
};
|
|
|
|
template <class T>
|
|
void swap ( optional<T&>& x, optional<T&>& y) BOOST_NOEXCEPT
|
|
{
|
|
x.swap(y);
|
|
}
|
|
|
|
} // namespace boost
|
|
|
|
#endif // 1/0
|
|
|
|
#endif // header guard
|