weakly_incrementable.hpp

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//
// Created by cosge on 2023-12-02.
//
 
#ifndef VCCC_ITERATOR_WEAKLY_INCREMENTABLE_HPP_
#define VCCC_ITERATOR_WEAKLY_INCREMENTABLE_HPP_
 
#include <type_traits>
 
#include "vccc/__concepts/same_as.hpp"
#include "vccc/__concepts/movable.hpp"
#include "vccc/__iterator/iter_difference_t.hpp"
#include "vccc/__type_traits/conjunction.hpp"
#include "vccc/__type_traits/has_typename_type.hpp"
#include "vccc/__type_traits/is_integer_like.hpp"
#include "vccc/__type_traits/void_t.hpp"
 
namespace vccc {
namespace detail {
 
template<typename T, bool = has_typename_type<iter_difference<T>>::value>
struct is_signed_integer_like_iter_difference : std::false_type {};
 
template<typename T>
struct is_signed_integer_like_iter_difference<T, true>
    : is_signed_integer_like<iter_difference_t<T>> {};
 
template<typename T, typename = void>
struct is_pre_incrementable : std::false_type {};
 
template<typename T>
struct is_pre_incrementable<T, void_t<decltype( ++std::declval<T&>() )>> : same_as<decltype( ++std::declval<T&>() ), T&> {};
 
template<typename T, typename = void>
struct is_post_incrementable : std::false_type {};
 
template<typename T>
struct is_post_incrementable<T, void_t<decltype( std::declval<T&>()++ )>> : std::true_type {};
 
} // namespace detail
 
 
template<typename I>
struct weakly_incrementable
    : conjunction<
        movable<I>,
        detail::is_signed_integer_like_iter_difference<I>,
        detail::is_pre_incrementable<I>,
        detail::is_post_incrementable<I>
      > {};
 
 
} // namespace vccc
 
#endif // VCCC_ITERATOR_WEAKLY_INCREMENTABLE_HPP_