262 lines · cpp
1// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s2// expected-no-diagnostics3 4// Example tuple implementation from the variadic templates proposal,5// ISO C++ committee document number N2080.6 7// Helper type traits8template<typename T>9struct add_reference {10 typedef T &type;11};12 13template<typename T>14struct add_reference<T&> {15 typedef T &type;16};17 18template<typename T>19struct add_const_reference {20 typedef T const &type;21};22 23template<typename T>24struct add_const_reference<T&> {25 typedef T &type;26};27 28template<typename T, typename U>29struct is_same {30 static const bool value = false;31};32 33template<typename T>34struct is_same<T, T> {35 static const bool value = true;36};37 38template<typename T> 39class reference_wrapper { 40 T *ptr;41 42public:43 reference_wrapper(T& t) : ptr(&t) { }44 operator T&() const { return *ptr; }45};46 47template<typename T> reference_wrapper<T> ref(T& t) { 48 return reference_wrapper<T>(t); 49}50template<typename T> reference_wrapper<const T> cref(const T& t) {51 return reference_wrapper<const T>(t); 52}53 54template<typename... Values> class tuple;55 56// Basis case: zero-length tuple57template<> class tuple<> { };58 59template<typename Head, typename... Tail> 60class tuple<Head, Tail...> : private tuple<Tail...> { 61 typedef tuple<Tail...> inherited;62 63public: 64 tuple() { }65 // implicit copy-constructor is okay66 67 // Construct tuple from separate arguments. 68 tuple(typename add_const_reference<Head>::type v,69 typename add_const_reference<Tail>::type... vtail) 70 : m_head(v), inherited(vtail...) { }71 72 // Construct tuple from another tuple. 73 template<typename... VValues> tuple(const tuple<VValues...>& other)74 : m_head(other.head()), inherited(other.tail()) { }75 76 template<typename... VValues> tuple& 77 operator=(const tuple<VValues...>& other) {78 m_head = other.head(); 79 tail() = other.tail(); 80 return *this;81 }82 83 typename add_reference<Head>::type head() { return m_head; } 84 typename add_reference<const Head>::type head() const { return m_head; }85 inherited& tail() { return *this; } 86 const inherited& tail() const { return *this; }87 88protected: 89 Head m_head;90};91 92void test_tuple() {93 tuple<> t0a;94 tuple<> t0b(t0a);95 t0a = t0b;96 97 tuple<int> t1a;98 tuple<int> t1b(17);99 tuple<int> t1c(t1b);100 t1a = t1b;101 102 tuple<float> t1d(3.14159);103 tuple<float> t1e(t1d);104 t1d = t1e;105 106 int i;107 float f;108 double d;109 tuple<int*, float*, double*> t3a(&i, &f, &d);110}111 112// Creation functions113template<typename T> 114struct make_tuple_result {115 typedef T type;116};117 118template<typename T> 119struct make_tuple_result<reference_wrapper<T> > {120 typedef T& type;121};122 123template<typename... Values> 124tuple<typename make_tuple_result<Values>::type...> 125make_tuple(const Values&... values) {126 return tuple<typename make_tuple_result<Values>::type...>(values...);127}128 129template<typename... Values> 130tuple<Values&...> tie(Values&... values) {131 return tuple<Values&...>(values...);132}133 134template<typename T> const T *addr(const T& ref) { return &ref; }135void test_creation_functions() {136 int i;137 float f;138 double d;139 const tuple<int, float&, const double&> *t3p = addr(make_tuple(i, ref(f), cref(d)));140 const tuple<int&, float&, double&> *t3q = addr(tie(i, f, d));141}142 143// Helper classes144template<typename Tuple> struct tuple_size;145 146template<typename... Values> struct tuple_size<tuple<Values...> > {147 static const int value = sizeof...(Values);148};149 150int check_tuple_size_0[tuple_size<tuple<> >::value == 0? 1 : -1];151int check_tuple_size_1[tuple_size<tuple<int>>::value == 1? 1 : -1];152int check_tuple_size_2[tuple_size<tuple<float, double>>::value == 2? 1 : -1];153int check_tuple_size_3[tuple_size<tuple<char, unsigned char, signed char>>::value == 3? 1 : -1];154 155template<int I, typename Tuple> struct tuple_element;156 157template<int I, typename Head, typename... Tail> 158struct tuple_element<I, tuple<Head, Tail...> > {159 typedef typename tuple_element<I-1, tuple<Tail...> >::type type;160};161 162template<typename Head, typename... Tail> 163struct tuple_element<0, tuple<Head, Tail...> > {164 typedef Head type;165};166 167int check_tuple_element_0[is_same<tuple_element<0, tuple<int&, float, double>>::type,168 int&>::value? 1 : -1];169 170int check_tuple_element_1[is_same<tuple_element<1, tuple<int&, float, double>>::type,171 float>::value? 1 : -1];172 173int check_tuple_element_2[is_same<tuple_element<2, tuple<int&, float, double>>::type,174 double>::value? 1 : -1];175 176// Element access177template<int I, typename Tuple> class get_impl;178template<int I, typename Head, typename... Values> 179class get_impl<I, tuple<Head, Values...> > {180 typedef typename tuple_element<I-1, tuple<Values...> >::type Element;181 typedef typename add_reference<Element>::type RJ; 182 typedef typename add_const_reference<Element>::type PJ;183 typedef get_impl<I-1, tuple<Values...> > Next;184public: 185 static RJ get(tuple<Head, Values...>& t) { return Next::get(t.tail()); }186 static PJ get(const tuple<Head, Values...>& t) { return Next::get(t.tail()); }187};188 189template<typename Head, typename... Values> 190class get_impl<0, tuple<Head, Values...> > {191 typedef typename add_reference<Head>::type RJ; 192 typedef typename add_const_reference<Head>::type PJ;193public: 194 static RJ get(tuple<Head, Values...>& t) { return t.head(); } 195 static PJ get(const tuple<Head, Values...>& t) { return t.head(); }196};197 198template<int I, typename... Values> typename add_reference<199typename tuple_element<I, tuple<Values...> >::type >::type200get(tuple<Values...>& t) { 201 return get_impl<I, tuple<Values...> >::get(t);202}203 204template<int I, typename... Values> typename add_const_reference<205typename tuple_element<I, tuple<Values...> >::type >::type206get(const tuple<Values...>& t) { 207 return get_impl<I, tuple<Values...> >::get(t);208}209 210void test_element_access(tuple<int*, float*, double*&> t3) {211 int i;212 float f;213 double d;214 get<0>(t3) = &i;215 get<1>(t3) = &f;216 get<2>(t3) = &d;217}218 219// Relational operators220inline bool operator==(const tuple<>&, const tuple<>&) { return true; }221 222template<typename T, typename... TTail, typename U, typename... UTail> 223bool operator==(const tuple<T, TTail...>& t, const tuple<U, UTail...>& u) {224 return t.head() == u.head() && t.tail() == u.tail();225}226 227template<typename... TValues, typename... UValues> 228bool operator!=(const tuple<TValues...>& t, const tuple<UValues...>& u) {229 return !(t == u); 230}231 232inline bool operator<(const tuple<>&, const tuple<>&) { return false; }233 234template<typename T, typename... TTail, typename U, typename... UTail> 235bool operator<(const tuple<T, TTail...>& t, const tuple<U, UTail...>& u) {236 return (t.head() < u.head() || (!(t.head() < u.head()) && t.tail() < u.tail()));237}238 239template<typename... TValues, typename... UValues> 240bool operator>(const tuple<TValues...>& t, const tuple<UValues...>& u) {241 return u < t;242}243 244template<typename... TValues, typename... UValues>245bool operator<=(const tuple<TValues...>& t, const tuple<UValues...>& u) {246 return !(u < t);247}248 249template<typename... TValues, typename... UValues>250bool operator>=(const tuple<TValues...>& t, const tuple<UValues...>& u) {251 return !(t < u);252}253 254void test_relational_operators(tuple<int*, float*, double*> t3) {255 (void)(t3 == t3);256 (void)(t3 != t3);257 (void)(t3 < t3);258 (void)(t3 <= t3);259 (void)(t3 >= t3);260 (void)(t3 > t3);261};262