Traits.h

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#ifndef ZSERIO_TRAITS_H_INC
#define ZSERIO_TRAITS_H_INC
 
#include <type_traits>
 
#include "zserio/NoInit.h"
#include "zserio/RebindAlloc.h"
 
namespace zserio
{
 
// forward declaration
class BitStreamReader;
struct PropagateAllocatorT;
template <typename>
class BasicPackingContextNode;
template <typename, std::size_t>
class Span;
 
namespace detail
{
 
template <typename>
class inplace_optional_holder;
 
template <typename, typename>
class heap_optional_holder;
 
// These decltype's wrappers are needed because of old MSVC compiler 2015.
template <typename T, typename U = decltype(&T::initialize)>
struct decltype_initialize
{
    using type = U;
};
 
template <typename T, typename U = decltype(&T::initializeChildren)>
struct decltype_initialize_children
{
    using type = U;
};
 
template <typename T, typename U = decltype(std::declval<T>().reflectable())>
struct decltype_reflectable
{
    using type = U;
};
 
// declval is needed because otherwise MSVC 2015 states that std::allocator<int> does NOT have allocate method!
template <typename T, typename U = decltype(std::declval<T>().allocate(0))>
struct decltype_allocate
{
    using type = U;
};
 
template <typename T, typename U = decltype(std::declval<T>().deallocate(nullptr, 0))>
struct decltype_deallocate
{
    using type = U;
};
 
template <typename T, typename U = decltype(std::declval<T>().getValue())>
struct decltype_get_value
{
    using type = U;
};
 
template <typename T, typename U = decltype(&T::initializeOffset)>
struct decltype_initialize_offset
{
    using type = U;
};
 
template <typename T, typename U = decltype(&T::checkOffset)>
struct decltype_check_offset
{
    using type = U;
};
 
template <typename T, typename U = decltype(&T::initializeElement)>
struct decltype_initialize_element
{
    using type = U;
};
 
template <typename... T>
struct make_void
{
    using type = void;
};
 
template <typename... T>
using void_t = typename make_void<T...>::type;
 
} // namespace detail
 
template <typename T, typename = void>
struct is_allocator : std::false_type
{};
 
template <typename T>
struct is_allocator<T,
        detail::void_t<typename detail::decltype_allocate<T>::type,
                typename detail::decltype_deallocate<T>::type>> : std::true_type
{};
template <typename... ARGS>
struct is_first_allocator : std::false_type
{};
 
template <typename T, typename... ARGS>
struct is_first_allocator<T, ARGS...> : is_allocator<T>
{};
template <typename T, typename = void>
struct has_owner_type : std::false_type
{};
 
template <typename T>
struct has_owner_type<T, detail::void_t<typename T::OwnerType>> : std::true_type
{};
template <typename T, typename = void>
struct has_zserio_packing_context : std::false_type
{};
 
template <typename T>
struct has_zserio_packing_context<T, detail::void_t<typename T::ZserioPackingContext>> : std::true_type
{};
template <typename T, typename = void>
struct has_allocator : std::false_type
{};
 
template <typename T>
struct has_allocator<T, detail::void_t<typename T::allocator_type>> : std::true_type
{};
template <typename T, typename = void>
struct has_initialize : std::false_type
{};
 
template <typename T>
struct has_initialize<T, detail::void_t<typename detail::decltype_initialize<T>::type>> : std::true_type
{};
template <typename T, typename = void>
struct has_initialize_children : std::false_type
{};
 
template <typename T>
struct has_initialize_children<T, detail::void_t<typename detail::decltype_initialize_children<T>::type>>
        : std::true_type
{};
template <typename T, typename = void>
struct has_reflectable : std::false_type
{};
 
template <typename T>
struct has_reflectable<T, detail::void_t<typename detail::decltype_reflectable<T>::type>> : std::true_type
{};
template <typename T, typename = void>
struct has_initialize_offset : std::false_type
{};
 
template <typename T>
struct has_initialize_offset<T, detail::void_t<typename detail::decltype_initialize_offset<T>::type>>
        : std::true_type
{};
template <typename T, typename = void>
struct has_check_offset : std::false_type
{};
 
template <typename T>
struct has_check_offset<T, detail::void_t<typename detail::decltype_check_offset<T>::type>> : std::true_type
{};
template <typename T, typename = void>
struct has_initialize_element : std::false_type
{};
 
template <typename T>
struct has_initialize_element<T, detail::void_t<typename detail::decltype_initialize_element<T>::type>>
        : std::true_type
{};
template <typename T, typename = void>
struct is_bitmask : std::false_type
{};
 
template <typename T>
struct is_bitmask<T, detail::void_t<typename detail::decltype_get_value<T>::type, typename T::underlying_type>>
        : std::true_type
{};
template <typename>
struct is_span : std::false_type
{};
 
template <typename T, size_t Extent>
struct is_span<Span<T, Extent>> : std::true_type
{};
template <typename FIELD_TYPE, typename COMPOUND_TYPE, typename ALLOCATOR_TYPE, typename = void>
struct is_field_constructor_enabled
        : std::enable_if<!std::is_same<typename std::decay<FIELD_TYPE>::type, ALLOCATOR_TYPE>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, BitStreamReader>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, COMPOUND_TYPE>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, PropagateAllocatorT>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, NoInitT>::value,
                  int>
{};
 
template <typename FIELD_TYPE, typename COMPOUND_TYPE, typename ALLOCATOR_TYPE>
struct is_field_constructor_enabled<FIELD_TYPE, COMPOUND_TYPE, ALLOCATOR_TYPE,
        detail::void_t<typename COMPOUND_TYPE::ZserioPackingContext>>
        : std::enable_if<!std::is_same<typename std::decay<FIELD_TYPE>::type, ALLOCATOR_TYPE>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, BitStreamReader>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, COMPOUND_TYPE>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, PropagateAllocatorT>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type, NoInitT>::value &&
                          !std::is_same<typename std::decay<FIELD_TYPE>::type,
                                  typename COMPOUND_TYPE::ZserioPackingContext>::value,
                  int>
{};
template <typename FIELD_TYPE, typename COMPOUND_TYPE, typename ALLOCATOR_TYPE>
using is_field_constructor_enabled_t =
        typename is_field_constructor_enabled<FIELD_TYPE, COMPOUND_TYPE, ALLOCATOR_TYPE>::type;
 
} // namespace zserio
 
#endif // ifndef ZSERIO_TRAITS_H_INC