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//
// immer: immutable data structures for C++
// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
//
// This software is distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
//
#pragma once
#include <algorithm>
#include <iterator>
#include <memory>
#include <type_traits>
#include <utility>
namespace immer {
namespace detail {
template <typename... Ts>
struct make_void
{
using type = void;
};
template <typename... Ts>
using void_t = typename make_void<Ts...>::type;
template <typename T, typename = void>
struct is_dereferenceable : std::false_type
{};
template <typename T>
struct is_dereferenceable<T, void_t<decltype(*(std::declval<T&>()))>>
: std::true_type
{};
template <typename T>
constexpr bool is_dereferenceable_v = is_dereferenceable<T>::value;
template <typename T, typename U = T, typename = void>
struct is_equality_comparable : std::false_type
{};
template <typename T, typename U>
struct is_equality_comparable<
T,
U,
std::enable_if_t<std::is_same<bool,
decltype(std::declval<T&>() ==
std::declval<U&>())>::value>>
: std::true_type
{};
template <typename T, typename U = T>
constexpr bool is_equality_comparable_v = is_equality_comparable<T, U>::value;
template <typename T, typename U = T, typename = void>
struct is_inequality_comparable : std::false_type
{};
template <typename T, typename U>
struct is_inequality_comparable<
T,
U,
std::enable_if_t<std::is_same<bool,
decltype(std::declval<T&>() !=
std::declval<U&>())>::value>>
: std::true_type
{};
template <typename T, typename U = T>
constexpr bool is_inequality_comparable_v =
is_inequality_comparable<T, U>::value;
template <typename T, typename = void>
struct is_preincrementable : std::false_type
{};
template <typename T>
struct is_preincrementable<
T,
std::enable_if_t<std::is_same<T&, decltype(++(std::declval<T&>()))>::value>>
: std::true_type
{};
template <typename T>
constexpr bool is_preincrementable_v = is_preincrementable<T>::value;
template <typename T, typename U = T, typename = void>
struct is_subtractable : std::false_type
{};
template <typename T, typename U>
struct is_subtractable<
T,
U,
void_t<decltype(std::declval<T&>() - std::declval<U&>())>> : std::true_type
{};
template <typename T, typename U = T>
constexpr bool is_subtractable_v = is_subtractable<T, U>::value;
namespace swappable {
using std::swap;
template <typename T, typename U, typename = void>
struct with : std::false_type
{};
// Does not account for non-referenceable types
template <typename T, typename U>
struct with<T,
U,
void_t<decltype(swap(std::declval<T&>(), std::declval<U&>())),
decltype(swap(std::declval<U&>(), std::declval<T&>()))>>
: std::true_type
{};
} // namespace swappable
template <typename T, typename U>
using is_swappable_with = swappable::with<T, U>;
template <typename T>
using is_swappable = is_swappable_with<T, T>;
template <typename T>
constexpr bool is_swappable_v = is_swappable_with<T&, T&>::value;
template <typename T, typename = void>
struct is_iterator : std::false_type
{};
// See http://en.cppreference.com/w/cpp/concept/Iterator
template <typename T>
struct is_iterator<
T,
void_t<
std::enable_if_t<is_preincrementable_v<T> &&
is_dereferenceable_v<T>
// accounts for non-referenceable types
&& std::is_copy_constructible<T>::value &&
std::is_copy_assignable<T>::value &&
std::is_destructible<T>::value && is_swappable_v<T>>,
typename std::iterator_traits<T>::value_type,
typename std::iterator_traits<T>::difference_type,
typename std::iterator_traits<T>::reference,
typename std::iterator_traits<T>::pointer,
typename std::iterator_traits<T>::iterator_category>> : std::true_type
{};
template <typename T>
constexpr bool is_iterator_v = is_iterator<T>::value;
template <typename T, typename U, typename = void>
struct compatible_sentinel : std::false_type
{};
template <typename T, typename U>
struct compatible_sentinel<
T,
U,
std::enable_if_t<is_iterator_v<T> && is_equality_comparable_v<T, U> &&
is_inequality_comparable_v<T, U>>> : std::true_type
{};
template <typename T, typename U>
constexpr bool compatible_sentinel_v = compatible_sentinel<T, U>::value;
template <typename T, typename = void>
struct is_forward_iterator : std::false_type
{};
template <typename T>
struct is_forward_iterator<
T,
std::enable_if_t<is_iterator_v<T> &&
std::is_base_of<std::forward_iterator_tag,
typename std::iterator_traits<
T>::iterator_category>::value>>
: std::true_type
{};
template <typename T>
constexpr bool is_forward_iterator_v = is_forward_iterator<T>::value;
template <typename T, typename U, typename = void>
struct std_distance_supports : std::false_type
{};
template <typename T, typename U>
struct std_distance_supports<
T,
U,
void_t<decltype(std::distance(std::declval<T>(), std::declval<U>()))>>
: std::true_type
{};
template <typename T, typename U>
constexpr bool std_distance_supports_v = std_distance_supports<T, U>::value;
template <typename T, typename U, typename V, typename = void>
struct std_uninitialized_copy_supports : std::false_type
{};
template <typename T, typename U, typename V>
struct std_uninitialized_copy_supports<
T,
U,
V,
void_t<decltype(std::uninitialized_copy(
std::declval<T>(), std::declval<U>(), std::declval<V>()))>>
: std::true_type
{};
template <typename T, typename U, typename V>
constexpr bool std_uninitialized_copy_supports_v =
std_uninitialized_copy_supports<T, U, V>::value;
} // namespace detail
} // namespace immer
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