include/nlohmann/detail/iterators/iterator_traits.hpp

//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++
// |  |  |__   |  |  | | | |  version 3.11.3
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#pragma once

#include <iterator>  // random_access_iterator_tag

#include <nlohmann/detail/abi_macros.hpp>
#include <nlohmann/detail/meta/cpp_future.hpp>
#include <nlohmann/detail/meta/void_t.hpp>

NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{

template<typename It, typename = void>
struct iterator_types
{};

template<typename It>
struct iterator_types<
    It,
    void_t<typename It::difference_type, typename It::value_type, typename It::pointer, typename It::reference, typename It::iterator_category>>
{
    using difference_type = typename It::difference_type;
    using value_type = typename It::value_type;
    using pointer = typename It::pointer;
    using reference = typename It::reference;
    using iterator_category = typename It::iterator_category;
};

// This is required as some compilers implement std::iterator_traits in a way that
// doesn't work with SFINAE. See https://github.com/nlohmann/json/issues/1341.
template<typename T, typename = void>
struct iterator_traits
{};

template<typename T>
struct iterator_traits<T, enable_if_t<!std::is_pointer<T>::value>> : iterator_types<T>
{};

template<typename T>
struct iterator_traits<T*, enable_if_t<std::is_object<T>::value>>
{
    using iterator_category = std::random_access_iterator_tag;
    using value_type = T;
    using difference_type = ptrdiff_t;
    using pointer = T*;
    using reference = T&;
};

}  // namespace detail
NLOHMANN_JSON_NAMESPACE_END