1// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s 2// expected-no-diagnostics 3 4// Example tuple implementation from the variadic templates proposal, 5// ISO C++ committee document number N2080. 6 7// Helper type traits 8template<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 tuple 57template<> 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 okay 66 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 functions 113template<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 classes 144template<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 access 177template<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 >::type 200get(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 >::type 206get(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 operators 220inline 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