iterator_traits.hpp

//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++
// |  |  |__   |  |  | | | |  version 3.12.0
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2025 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/void_t.hpp>
#include <nlohmann/detail/meta/cpp_future.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