libstdc++-v3/testsuite/experimental/any/misc/any_cast.cc

   1 // { dg-do run { target c++14 } }
   2
   3 // Copyright (C) 2014-2024 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <experimental/any>
  21 #include <string>
  22 #include <cstring>
  23 #include <testsuite_hooks.h>
  24
  25 using std::experimental::any;
  26 using std::experimental::any_cast;
  27 using std::experimental::bad_any_cast;
  28
  29 void test01()
  30 {
  31   using std::string;
  32   using std::strcmp;
  33
  34   // taken from example in N3804 proposal
  35
  36   any x(5);                                   // x holds int
  37   VERIFY(any_cast<int>(x) == 5);              // cast to value
  38   any_cast<int&>(x) = 10;                     // cast to reference
  39   VERIFY(any_cast<int>(x) == 10);
  40
  41   x = "Meow";                                 // x holds const char*
  42   VERIFY(strcmp(any_cast<const char*>(x), "Meow") == 0);
  43   any_cast<const char*&>(x) = "Harry";
  44   VERIFY(strcmp(any_cast<const char*>(x), "Harry") == 0);
  45
  46   x = string("Meow");                         // x holds string
  47   string s, s2("Jane");
  48   s = move(any_cast<string&>(x));             // move from any
  49   VERIFY(s == "Meow");
  50   any_cast<string&>(x) = move(s2);            // move to any
  51   VERIFY(any_cast<const string&>(x) == "Jane");
  52
  53   string cat("Meow");
  54   const any y(cat);                           // const y holds string
  55   VERIFY(any_cast<const string&>(y) == cat);
  56 }
  57
  58 void test02()
  59 {
  60   any x(1);
  61   auto p = any_cast<double>(&x);
  62   VERIFY(p == nullptr);
  63
  64   x = 1.0;
  65   p = any_cast<double>(&x);
  66   VERIFY(p != nullptr);
  67
  68   x = any();
  69   p = any_cast<double>(&x);
  70   VERIFY(p == nullptr);
  71
  72   try {
  73     any_cast<double>(x);
  74     VERIFY(false);
  75   } catch (const bad_any_cast&) {
  76   }
  77 }
  78
  79 static int move_count = 0;
  80
  81 void test03()
  82 {
  83   struct MoveEnabled
  84   {
  85     MoveEnabled(MoveEnabled&&)
  86     {
  87       ++move_count;
  88     }
  89     MoveEnabled() = default;
  90     MoveEnabled(const MoveEnabled&) = default;
  91   };
  92   MoveEnabled m;
  93   MoveEnabled m2 = any_cast<MoveEnabled>(any(m));
  94   VERIFY(move_count == 1);
  95   MoveEnabled&& m3 = any_cast<MoveEnabled&&>(any(m));
  96   VERIFY(move_count == 1);
  97   struct MoveDeleted
  98   {
  99     MoveDeleted(MoveDeleted&&) = delete;
 100     MoveDeleted() = default;
 101     MoveDeleted(const MoveDeleted&) = default;
 102   };
 103   MoveDeleted md;
 104   MoveDeleted&& md2 = any_cast<MoveDeleted>(any(std::move(md)));
 105   MoveDeleted&& md3 = any_cast<MoveDeleted&&>(any(std::move(md)));
 106 }
 107
 108 void test05()
 109 {
 110   // PR libstdc++/69321
 111   struct noncopyable {
 112     noncopyable(noncopyable const&) = delete;
 113   };
 114
 115   any a;
 116   auto p = any_cast<noncopyable>(&a);
 117   VERIFY( p == nullptr );
 118 }
 119
 120 void test06()
 121 {
 122   // The contained value of a std::any is always an object type,
 123   // but any_cast does not forbid checking for function types.
 124
 125   any a(1);
 126   void (*p1)() = any_cast<void()>(&a);
 127   VERIFY( p1 == nullptr );
 128   int (*p2)(int) = any_cast<int(int)>(&a);
 129   VERIFY( p2 == nullptr );
 130   int (*p3)() = any_cast<int()>(&const_cast<const any&>(a));
 131   VERIFY( p3 == nullptr );
 132
 133   try {
 134     any_cast<int(&)()>(a);
 135     VERIFY( false );
 136   } catch (const bad_any_cast&) {
 137   }
 138
 139   try {
 140     any_cast<int(&)()>(std::move(a));
 141     VERIFY( false );
 142   } catch (const bad_any_cast&) {
 143   }
 144
 145   try {
 146     any_cast<int(&)()>(const_cast<const any&>(a));
 147     VERIFY( false );
 148   } catch (const bad_any_cast&) {
 149   }
 150 }
 151
 152 void test07()
 153 {
 154   int arr[3];
 155   any a(arr);
 156 #if __cpp_rtti
 157   VERIFY( a.type() == typeid(int*) );   // contained value is decayed
 158 #endif
 159
 160   int (*p1)[3] = any_cast<int[3]>(&a);
 161 #if __cpp_rtti
 162   VERIFY( a.type() != typeid(int[3]) ); // so any_cast should return nullptr
 163 #endif
 164   VERIFY( p1 == nullptr );
 165   int (*p2)[] = any_cast<int[]>(&a);
 166 #if __cpp_rtti
 167   VERIFY( a.type() != typeid(int[]) );  // so any_cast should return nullptr
 168 #endif
 169   VERIFY( p2 == nullptr );
 170   const int (*p3)[] = any_cast<int[]>(&const_cast<const any&>(a));
 171   VERIFY( p3 == nullptr );
 172 }
 173
 174 int main()
 175 {
 176   test01();
 177   test02();
 178   test03();
 179   test05();
 180   test06();
 181   test07();
 182 }