Sprout/sprout/optional/optional.hpp
2019-01-07 17:47:17 +09:00

468 lines
16 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
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 SPROUT_OPTIONAL_OPTIONAL_HPP
#define SPROUT_OPTIONAL_OPTIONAL_HPP
#include <type_traits>
#include <initializer_list>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/detail/predef.hpp>
#include <sprout/utility/value_holder/value_holder.hpp>
#include <sprout/utility/value_holder/get.hpp>
#include <sprout/utility/swap.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/utility/move.hpp>
#include <sprout/type_traits/is_constructible.hpp>
#include <sprout/type_traits/is_convert_constructible.hpp>
#include <sprout/iterator/reverse_iterator.hpp>
#include <sprout/iterator/value_iterator.hpp>
#include <sprout/none.hpp>
#include <sprout/optional/nullopt.hpp>
#include <sprout/optional/in_place.hpp>
#include <sprout/optional/exceptions.hpp>
#include <sprout/assert.hpp>
namespace sprout {
//
// optional
//
template<typename T>
class optional {
public:
typedef T type;
private:
typedef sprout::value_holder<type> holder_type;
public:
typedef typename holder_type::value_type value_type;
typedef typename holder_type::lvalue_reference lvalue_reference;
typedef typename holder_type::rvalue_reference rvalue_reference;
typedef typename holder_type::reference reference;
typedef typename holder_type::const_lvalue_reference const_lvalue_reference;
typedef typename holder_type::const_rvalue_reference const_rvalue_reference;
typedef typename holder_type::const_reference const_reference;
typedef typename holder_type::pointer pointer;
typedef typename holder_type::const_pointer const_pointer;
typedef typename holder_type::lvalue_reference_type lvalue_reference_type;
typedef typename holder_type::rvalue_reference_type rvalue_reference_type;
typedef typename holder_type::reference_type reference_type;
typedef typename holder_type::reference_const_type reference_const_type;
typedef typename holder_type::pointer_type pointer_type;
typedef typename holder_type::pointer_const_type pointer_const_type;
//
typedef typename sprout::value_iterator<reference> iterator;
typedef typename sprout::value_iterator<const_reference> const_iterator;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
typedef typename sprout::reverse_iterator<iterator> reverse_iterator;
typedef typename sprout::reverse_iterator<const_iterator> const_reverse_iterator;
public:
template<typename... Args>
struct is_constructible_args
: public sprout::is_constructible<T, Args&&...>
{};
public:
SPROUT_STATIC_CONSTEXPR size_type static_size = 1;
public:
static SPROUT_CONSTEXPR reference_type get(optional& t) SPROUT_NOEXCEPT {
return sprout::get(t.val);
}
static SPROUT_CONSTEXPR rvalue_reference_type get(optional&& t) SPROUT_NOEXCEPT {
return static_cast<rvalue_reference_type>(get(t));
}
static SPROUT_CONSTEXPR reference_const_type get(optional const& t) SPROUT_NOEXCEPT {
return sprout::get(t.val);
}
static SPROUT_CONSTEXPR pointer_type get_pointer(optional& t) SPROUT_NOEXCEPT {
return sprout::get_pointer(t.val);
}
static SPROUT_CONSTEXPR pointer_type get_pointer(optional&& t) SPROUT_NOEXCEPT {
return get_pointer(t);
}
static SPROUT_CONSTEXPR pointer_const_type get_pointer(optional const& t) SPROUT_NOEXCEPT {
return sprout::get_pointer(t.val);
}
static SPROUT_CONSTEXPR reference_type get_value_or(optional& t, reference_type v) SPROUT_NOEXCEPT {
return t.is_initialized() ? sprout::get(t.val)
: v
;
}
static SPROUT_CONSTEXPR rvalue_reference_type get_value_or(optional&& t, rvalue_reference_type v) SPROUT_NOEXCEPT {
return static_cast<rvalue_reference_type>(get_value_or(t, v));
}
static SPROUT_CONSTEXPR reference_const_type get_value_or(optional const& t, reference_const_type v) SPROUT_NOEXCEPT {
return t.is_initialized() ? sprout::get(t.val)
: v
;
}
private:
bool init;
holder_type val;
private:
SPROUT_CXX14_CONSTEXPR void destroy() SPROUT_NOEXCEPT {
init = false;
}
public:
// 20.6.4.1, constructors
SPROUT_CONSTEXPR optional() SPROUT_NOEXCEPT
: init(false)
{}
SPROUT_CONSTEXPR optional(sprout::nullopt_t) SPROUT_NOEXCEPT
: init(false)
{}
SPROUT_CONSTEXPR optional(optional const& v)
: init(v.init)
, val(v.is_initialized() ? holder_type(*v) : holder_type())
{}
#if SPROUT_GCC_IN_RANGE((4, 8, 0), (4, 8, 2))
optional(optional&&) = default;
#else
SPROUT_CONSTEXPR optional(optional&& v)
SPROUT_NOEXCEPT_IF(std::is_nothrow_move_constructible<T>::value)
: init(v.init)
, val(v.is_initialized() ? holder_type(sprout::move(get(v))) : holder_type())
{}
#endif
SPROUT_CONSTEXPR optional(T const& v)
: init(true)
, val(v)
{}
// !!! TEMP: for T const&
// SPROUT_CONSTEXPR optional(T&& v)
// : init(true)
// , val(sprout::move(v))
// {}
template<
typename... Args,
typename = typename std::enable_if<is_constructible_args<Args...>::value>::type
>
explicit SPROUT_CONSTEXPR optional(sprout::in_place_t, Args&&... args)
: init(true)
, val(sprout::in_place, SPROUT_FORWARD(Args, args)...)
{}
template<
typename U, typename... Args,
typename = typename std::enable_if<is_constructible_args<std::initializer_list<U>&, Args...>::value>::type
>
explicit SPROUT_CONSTEXPR optional(sprout::in_place_t, std::initializer_list<U> il, Args&&... args)
: init(true)
, val(sprout::in_place, il, SPROUT_FORWARD(Args, args)...)
{}
SPROUT_CONSTEXPR optional(bool cond, T const& v)
: init(cond)
, val(cond ? holder_type(v) : holder_type())
{}
// !!! TEMP: for T const&
// SPROUT_CONSTEXPR optional(bool cond, T&& v)
// : init(cond)
// , val(cond ? holder_type(sprout::move(v)) : holder_type())
// {}
template<typename U>
explicit SPROUT_CONSTEXPR optional(optional<U> const& v)
: init(v.is_initialized())
, val(v.is_initialized() ? holder_type(*v) : holder_type())
{}
template<typename U>
explicit SPROUT_CONSTEXPR optional(optional<U>&& v)
: init(v.is_initialized())
, val(v.is_initialized() ? holder_type(sprout::move(optional<U>::get(v))) : holder_type())
{}
// 20.6.4.3, assignment
SPROUT_CXX14_CONSTEXPR optional& operator=(sprout::nullopt_t v) SPROUT_NOEXCEPT {
assign(v);
return *this;
}
SPROUT_CXX14_CONSTEXPR optional& operator=(optional const& v) {
assign(v);
return *this;
}
SPROUT_CXX14_CONSTEXPR optional& operator=(optional&& v)
SPROUT_NOEXCEPT_IF(std::is_move_constructible<T>::value && std::is_move_assignable<T>::value)
{
assign(SPROUT_FORWARD(optional, v));
return *this;
}
template<
typename U,
// typename = typename std::enable_if<std::is_constructible<T, U>::value && std::is_assignable<U, T>::value>::type
typename = typename std::enable_if<std::is_constructible<T, U&&>::value>::type
>
SPROUT_CXX14_CONSTEXPR optional& operator=(U&& v) {
assign(SPROUT_FORWARD(U, v));
return *this;
}
template<typename U>
SPROUT_CXX14_CONSTEXPR optional& operator=(optional<U> const& v) {
assign(v);
return *this;
}
template<typename U>
SPROUT_CXX14_CONSTEXPR optional& operator=(optional<U>&& v) {
assign(SPROUT_FORWARD(optional<U>, v));
return *this;
}
template<
typename... Args,
typename = typename std::enable_if<is_constructible_args<Args...>::value>::type
>
SPROUT_CXX14_CONSTEXPR void emplace(Args&&... args) {
optional temp(sprout::in_place, SPROUT_FORWARD(Args, args)...);
temp.swap(*this);
}
template<
typename U, typename... Args,
typename = typename std::enable_if<is_constructible_args<std::initializer_list<U>&, Args...>::value>::type
>
SPROUT_CXX14_CONSTEXPR void emplace(std::initializer_list<U> il, Args&&... args) {
optional temp(sprout::in_place, il, SPROUT_FORWARD(Args, args)...);
temp.swap(*this);
}
SPROUT_CXX14_CONSTEXPR void assign(sprout::nullopt_t) SPROUT_NOEXCEPT {
destroy();
}
SPROUT_CXX14_CONSTEXPR void assign(optional const& v) {
optional temp(v);
temp.swap(*this);
}
SPROUT_CXX14_CONSTEXPR void assign(optional&& v)
SPROUT_NOEXCEPT_IF(std::is_move_constructible<T>::value && std::is_move_assignable<T>::value)
{
optional temp(SPROUT_FORWARD(optional, v));
temp.swap(*this);
}
template<
typename U,
// typename = typename std::enable_if<std::is_constructible<T, U>::value && std::is_assignable<U, T>::value>::type
typename = typename std::enable_if<std::is_constructible<T, U&&>::value>::type
>
SPROUT_CXX14_CONSTEXPR void assign(U&& v) {
optional temp(SPROUT_FORWARD(U, v));
temp.swap(*this);
}
template<typename U>
SPROUT_CXX14_CONSTEXPR void assign(optional<U> const& v) {
optional temp(v);
temp.swap(*this);
}
template<typename U>
SPROUT_CXX14_CONSTEXPR void assign(optional<U>&& v) {
optional temp(SPROUT_FORWARD(optional<U>, v));
temp.swap(*this);
}
SPROUT_CXX14_CONSTEXPR void reset() SPROUT_NOEXCEPT {
destroy();
}
SPROUT_CXX14_CONSTEXPR void reset(sprout::nullopt_t v) SPROUT_NOEXCEPT {
assign(v);
}
template<
typename U,
// typename = typename std::enable_if<std::is_constructible<T, U>::value && std::is_assignable<U, T>::value>::type
typename = typename std::enable_if<std::is_constructible<T, U&&>::value>::type
>
SPROUT_CXX14_CONSTEXPR void reset(U&& v) {
assign(SPROUT_FORWARD(U, v));
}
// 20.6.4.4, swap
SPROUT_CXX14_CONSTEXPR void swap(optional& other)
SPROUT_NOEXCEPT_IF_EXPR(sprout::swap(val, other.val))
{
sprout::swap(init, other.init);
sprout::swap(val, other.val);
}
// 20.6.4.5, observers
SPROUT_CONSTEXPR pointer_const_type operator->() const {
return SPROUT_ASSERT(is_initialized()),
val.get_pointer()
;
}
SPROUT_CXX14_CONSTEXPR pointer_type operator->() {
return SPROUT_ASSERT(is_initialized()),
val.get_pointer()
;
}
SPROUT_CONSTEXPR pointer_const_type get_pointer() const {
return is_initialized() ? val.get_pointer()
: 0
;
}
SPROUT_CXX14_CONSTEXPR pointer_type get_pointer() {
return is_initialized() ? val.get_pointer()
: 0
;
}
SPROUT_CONSTEXPR pointer_const_type get_ptr() const {
return get_pointer();
}
SPROUT_CXX14_CONSTEXPR pointer_type get_ptr() {
return get_pointer();
}
SPROUT_CONSTEXPR reference_const_type operator*() const {
return (SPROUT_ASSERT(is_initialized()), true) ? val.get()
: val.get()
;
}
SPROUT_CXX14_CONSTEXPR reference_type operator*() {
return (SPROUT_ASSERT(is_initialized()), true) ? val.get()
: val.get()
;
}
SPROUT_CONSTEXPR reference_const_type value() const {
return get();
}
SPROUT_CXX14_CONSTEXPR reference_type value() {
return get();
}
SPROUT_CONSTEXPR reference_const_type get() const {
return is_initialized() ? val.get()
: (throw sprout::bad_optional_access("optional<>: bad optional access"), val.get())
;
}
SPROUT_CXX14_CONSTEXPR reference_type get() {
return is_initialized() ? val.get()
: (throw sprout::bad_optional_access("optional<>: bad optional access"), val.get())
;
}
SPROUT_CONSTEXPR reference_const_type value_or(reference_const_type& v) const {
return get_value_or(v);
}
SPROUT_CXX14_CONSTEXPR reference_type value_or(reference_type& v) {
return get_value_or(v);
}
SPROUT_CONSTEXPR reference_const_type get_value_or(reference_const_type& v) const {
return is_initialized() ? val.get()
: v
;
}
SPROUT_CXX14_CONSTEXPR reference_type get_value_or(reference_type& v) {
return is_initialized() ? val.get()
: v
;
}
SPROUT_EXPLICIT_CONVERSION SPROUT_CONSTEXPR operator bool() const SPROUT_NOEXCEPT {
return is_initialized();
}
SPROUT_CONSTEXPR bool operator!() const SPROUT_NOEXCEPT {
return !is_initialized();
}
SPROUT_CONSTEXPR bool is_initialized() const SPROUT_NOEXCEPT {
return init;
}
// iterators:
SPROUT_CXX14_CONSTEXPR iterator begin() {
return is_initialized() ? iterator(val, static_size)
: iterator()
;
}
SPROUT_CONSTEXPR const_iterator begin() const {
return is_initialized() ? const_iterator(val, static_size)
: const_iterator()
;
}
SPROUT_CXX14_CONSTEXPR iterator end() SPROUT_NOEXCEPT {
return iterator();
}
SPROUT_CONSTEXPR const_iterator end() const SPROUT_NOEXCEPT {
return const_iterator();
}
SPROUT_CXX14_CONSTEXPR reverse_iterator rbegin() SPROUT_NOEXCEPT {
return reverse_iterator(end());
}
SPROUT_CONSTEXPR const_reverse_iterator rbegin() const SPROUT_NOEXCEPT {
return const_reverse_iterator(end());
}
SPROUT_CXX14_CONSTEXPR reverse_iterator rend() SPROUT_NOEXCEPT {
return reverse_iterator(begin());
}
SPROUT_CONSTEXPR const_reverse_iterator rend() const SPROUT_NOEXCEPT {
return const_reverse_iterator(begin());
}
SPROUT_CONSTEXPR const_iterator cbegin() const SPROUT_NOEXCEPT {
return is_initialized() ? const_iterator(val, static_size)
: const_iterator()
;
}
SPROUT_CONSTEXPR const_iterator cend() const SPROUT_NOEXCEPT {
return const_iterator();
}
SPROUT_CONSTEXPR const_reverse_iterator crbegin() const SPROUT_NOEXCEPT {
return const_reverse_iterator(end());
}
SPROUT_CONSTEXPR const_reverse_iterator crend() const SPROUT_NOEXCEPT {
return const_reverse_iterator(begin());
}
// capacity:
SPROUT_CONSTEXPR size_type size() const SPROUT_NOEXCEPT {
return is_initialized() ? static_size
: 0
;
}
SPROUT_CONSTEXPR size_type max_size() const SPROUT_NOEXCEPT {
return size();
}
SPROUT_CONSTEXPR bool empty() const SPROUT_NOEXCEPT {
return !is_initialized();
}
// element access:
SPROUT_CXX14_CONSTEXPR reference operator[](size_type) {
return val.get();
}
SPROUT_CONSTEXPR const_reference operator[](size_type) const {
return val.get();
}
SPROUT_CXX14_CONSTEXPR reference at(size_type i) {
return i < size() ? val.get()
: (throw std::out_of_range("optional<>: index out of range"), val.get())
;
}
SPROUT_CONSTEXPR const_reference at(size_type i) const {
return i < size() ? val.get()
: (throw std::out_of_range("optional<>: index out of range"), val.get())
;
}
SPROUT_CXX14_CONSTEXPR reference front() {
return val.get();
}
SPROUT_CONSTEXPR const_reference front() const {
return val.get();
}
SPROUT_CXX14_CONSTEXPR reference back() {
return val.get();
}
SPROUT_CONSTEXPR const_reference back() const {
return val.get();
}
// others:
SPROUT_CXX14_CONSTEXPR void rangecheck(size_type i) const {
return i >= size() ? throw std::out_of_range("optional<>: index out of range")
: (void)0
;
}
};
template<typename T>
SPROUT_CONSTEXPR_OR_CONST typename sprout::optional<T>::size_type sprout::optional<T>::static_size;
//
// swap
//
template<typename T>
inline SPROUT_CXX14_CONSTEXPR void
swap(sprout::optional<T>& lhs, sprout::optional<T>& rhs)
SPROUT_NOEXCEPT_IF_EXPR(lhs.swap(rhs))
{
lhs.swap(rhs);
}
} // namespace sprout
#endif // #ifndef SPROUT_OPTIONAL_OPTIONAL_HPP