json/include/nlohmann/detail/iterators/iterator_traits.hpp
2018-12-08 15:46:33 +00:00

49 lines
1.3 KiB
C++

#pragma once
#include <iterator> // random_access_iterator_tag
#include <nlohmann/detail/meta/void_t.hpp>
#include <nlohmann/detail/meta/cpp_future.hpp>
namespace nlohmann
{
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>> {
typedef std::random_access_iterator_tag iterator_category;
typedef T value_type;
typedef ptrdiff_t difference_type;
typedef T* pointer;
typedef T& reference;
};
}
}