1 #ifndef CPP_UTILITIES_TRAITS_H
2 #define CPP_UTILITIES_TRAITS_H
14 enum class Enabler {};
19 template <
typename If,
typename Then,
typename Else>
using Conditional =
typename std::conditional<If::value, Then, Else>::type;
22 template <
bool B,
typename...>
struct Bool : std::integral_constant<bool, B> {
29 template <
typename... T>
struct Any :
Bool<false> {
32 template <
typename Head,
typename... Tail>
struct Any<Head, Tail...> :
Conditional<Head, Bool<true>, Any<Tail...>> {
36 template <
typename... T>
struct All :
Bool<true> {
39 template <
typename Head,
typename... Tail>
struct All<Head, Tail...> :
Conditional<Head, All<Tail...>, Bool<false>> {
43 template <
typename... T>
struct None :
Bool<true> {
46 template <
typename Head,
typename... Tail>
struct None<Head, Tail...> :
Conditional<Head, Bool<false>, None<Tail...>> {
50 template <
typename... Condition>
using EnableIf =
typename std::enable_if<
All<Condition...>::value, Detail::Enabler>::type;
52 template <
typename... Condition>
using DisableIf =
typename std::enable_if<!
All<Condition...>::value, Detail::Enabler>::type;
55 template <
typename... Condition>
using EnableIfAny =
typename std::enable_if<
Any<Condition...>::value, Detail::Enabler>::type;
57 template <
typename... Condition>
using DisableIfAny =
typename std::enable_if<!
Any<Condition...>::value, Detail::Enabler>::type;
61 template <
typename T,
template <
typename...>
class Template>
struct IsSpecializationOfHelper :
Bool<false> {
63 template <
template <
typename...>
class Template,
typename... Args>
struct IsSpecializationOfHelper<Template<Args...>, Template> :
Bool<true> {
68 template <
typename Type,
template <
typename...>
class... TemplateTypes>
69 struct IsSpecializationOf : Detail::IsSpecializationOfHelper<typename std::remove_cv<Type>::type, TemplateTypes...> {
75 template <
typename Type,
template <
typename...>
class TemplateType,
template <
typename...>
class... RemainingTemplateTypes>
77 :
Conditional<IsSpecializationOf<Type, TemplateType>, Bool<true>, IsSpecializingAnyOf<Type, RemainingTemplateTypes...>> {
84 template <
typename Type,
typename OtherType,
typename... RemainingTypes>
85 struct IsAnyOf<Type, OtherType, RemainingTypes...> :
Conditional<std::is_same<Type, OtherType>, Bool<true>, IsAnyOf<Type, RemainingTypes...>> {
91 template <
typename Type,
typename OtherType,
typename... RemainingTypes>
92 struct IsNoneOf<Type, OtherType, RemainingTypes...> :
Conditional<std::is_same<Type, OtherType>, Bool<false>, IsNoneOf<Type, RemainingTypes...>> {
98 :
Bool<std::is_same<char const *, typename std::decay<T>::type>::value || std::is_same<char *, typename std::decay<T>::type>::value> {
101 template <
typename T>
struct IsString :
Bool<IsCString<T>::value || IsSpecializationOf<T, std::basic_string>::value> {
108 template <
typename T>
struct IsComplete<T, decltype(void(sizeof(T)))> :
Bool<true> {
115 #define CPP_UTILITIES_PP_COMMA ,
123 #define CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(CheckName, CheckCode) \
125 template <typename T> auto CheckName(int) -> decltype(CheckCode, ::CppUtilities::Traits::Bool<true>{}); \
126 template <typename T>::CppUtilities::Traits::Bool<false> CheckName(...); \
128 template <typename T> using CheckName = decltype(Detail::CheckName<T>(0))
148 std::begin(std::declval<T &>())
155 void(*begin(std::declval<T &>())));
158 template <
typename T, EnableIf<IsDereferencable<T>> * =
nullptr> constexpr
auto &
dereferenceMaybe(T &value)
164 template <
typename T, DisableIf<IsDereferencable<T>> * =
nullptr> constexpr
auto &
dereferenceMaybe(T &value)
170 template <
typename T, EnableIf<IsDereferencable<T>> * =
nullptr> constexpr
const auto &
dereferenceMaybe(
const T &value)
176 template <
typename T, DisableIf<IsDereferencable<T>> * =
nullptr> constexpr
const auto &
dereferenceMaybe(
const T &value)
185 #endif // CPP_UTILITIES_TRAITS_H