variant_swap.cpp 6.5 KB

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  1. // Copyright 2017 Peter Dimov.
  2. //
  3. // Distributed under the Boost Software License, Version 1.0.
  4. //
  5. // See accompanying file LICENSE_1_0.txt or copy at
  6. // http://www.boost.org/LICENSE_1_0.txt
  7. #include <boost/variant2/variant.hpp>
  8. #include <boost/core/lightweight_test.hpp>
  9. #include <boost/core/lightweight_test_trait.hpp>
  10. #include <type_traits>
  11. #include <utility>
  12. #include <string>
  13. using namespace boost::variant2;
  14. #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
  15. struct X1
  16. {
  17. int v;
  18. X1(): v(0) {}
  19. explicit X1(int v): v(v) {}
  20. X1(X1 const& r): v(r.v) {}
  21. X1(X1&& r): v(r.v) {}
  22. X1& operator=( X1 const& r ) { v = r.v; return *this; }
  23. X1& operator=( X1&& r ) { v = r.v; return *this; }
  24. };
  25. inline bool operator==( X1 const& a, X1 const& b ) { return a.v == b.v; }
  26. STATIC_ASSERT( !std::is_nothrow_default_constructible<X1>::value );
  27. STATIC_ASSERT( !std::is_nothrow_copy_constructible<X1>::value );
  28. STATIC_ASSERT( !std::is_nothrow_move_constructible<X1>::value );
  29. STATIC_ASSERT( !std::is_nothrow_copy_assignable<X1>::value );
  30. STATIC_ASSERT( !std::is_nothrow_move_assignable<X1>::value );
  31. struct X2
  32. {
  33. int v;
  34. X2(): v(0) {}
  35. explicit X2(int v): v(v) {}
  36. X2(X2 const& r): v(r.v) {}
  37. X2(X2&& r): v(r.v) {}
  38. X2& operator=( X2 const& r ) { v = r.v; return *this; }
  39. X2& operator=( X2&& r ) { v = r.v; return *this; }
  40. };
  41. inline bool operator==( X2 const& a, X2 const& b ) { return a.v == b.v; }
  42. STATIC_ASSERT( !std::is_nothrow_default_constructible<X2>::value );
  43. STATIC_ASSERT( !std::is_nothrow_copy_constructible<X2>::value );
  44. STATIC_ASSERT( !std::is_nothrow_move_constructible<X2>::value );
  45. STATIC_ASSERT( !std::is_nothrow_copy_assignable<X2>::value );
  46. STATIC_ASSERT( !std::is_nothrow_move_assignable<X2>::value );
  47. int main()
  48. {
  49. {
  50. variant<int> v;
  51. BOOST_TEST_EQ( get<0>(v), 0 );
  52. variant<int> v2( 1 );
  53. BOOST_TEST_EQ( get<0>(v2), 1 );
  54. swap( v, v2 );
  55. BOOST_TEST_EQ( get<0>(v), 1 );
  56. BOOST_TEST_EQ( get<0>(v2), 0 );
  57. variant<int> v3( 2 );
  58. BOOST_TEST_EQ( get<0>(v3), 2 );
  59. swap( v, v3 );
  60. BOOST_TEST_EQ( get<0>(v), 2 );
  61. BOOST_TEST_EQ( get<0>(v3), 1 );
  62. }
  63. {
  64. variant<int, float> v;
  65. BOOST_TEST_EQ( v.index(), 0 );
  66. BOOST_TEST_EQ( get<0>(v), 0 );
  67. variant<int, float> v2( 1 );
  68. BOOST_TEST_EQ( v2.index(), 0 );
  69. BOOST_TEST_EQ( get<0>(v2), 1 );
  70. swap( v, v2 );
  71. BOOST_TEST_EQ( v.index(), 0 );
  72. BOOST_TEST_EQ( get<0>(v), 1 );
  73. BOOST_TEST_EQ( v2.index(), 0 );
  74. BOOST_TEST_EQ( get<0>(v2), 0 );
  75. variant<int, float> v3( 3.14f );
  76. BOOST_TEST_EQ( v3.index(), 1 );
  77. BOOST_TEST_EQ( get<1>(v3), 3.14f );
  78. swap( v, v3 );
  79. BOOST_TEST_EQ( v.index(), 1 );
  80. BOOST_TEST_EQ( get<1>(v), 3.14f );
  81. BOOST_TEST_EQ( v3.index(), 0 );
  82. BOOST_TEST_EQ( get<0>(v3), 1 );
  83. variant<int, float> v4( 3.15f );
  84. BOOST_TEST_EQ( v4.index(), 1 );
  85. BOOST_TEST_EQ( get<1>(v4), 3.15f );
  86. swap( v, v4 );
  87. BOOST_TEST_EQ( v.index(), 1 );
  88. BOOST_TEST_EQ( get<1>(v), 3.15f );
  89. BOOST_TEST_EQ( v4.index(), 1 );
  90. BOOST_TEST_EQ( get<1>(v4), 3.14f );
  91. }
  92. {
  93. variant<int, int, float, std::string> v;
  94. BOOST_TEST_EQ( v.index(), 0 );
  95. BOOST_TEST_EQ( get<0>(v), 0 );
  96. variant<int, int, float, std::string> v2( in_place_index_t<1>{}, 1 );
  97. BOOST_TEST_EQ( v2.index(), 1 );
  98. BOOST_TEST_EQ( get<1>(v2), 1 );
  99. swap( v, v2 );
  100. BOOST_TEST_EQ( v.index(), 1 );
  101. BOOST_TEST_EQ( get<1>(v), 1 );
  102. BOOST_TEST_EQ( v2.index(), 0 );
  103. BOOST_TEST_EQ( get<0>(v2), 0 );
  104. variant<int, int, float, std::string> v3( 3.14f );
  105. BOOST_TEST_EQ( v3.index(), 2 );
  106. BOOST_TEST_EQ( get<2>(v3), 3.14f );
  107. swap( v, v3 );
  108. BOOST_TEST_EQ( v.index(), 2 );
  109. BOOST_TEST_EQ( get<2>(v), 3.14f );
  110. BOOST_TEST_EQ( v3.index(), 1 );
  111. BOOST_TEST_EQ( get<1>(v3), 1 );
  112. variant<int, int, float, std::string> v4( 3.15f );
  113. BOOST_TEST_EQ( v4.index(), 2 );
  114. BOOST_TEST_EQ( get<2>(v4), 3.15f );
  115. swap( v, v4 );
  116. BOOST_TEST_EQ( v.index(), 2 );
  117. BOOST_TEST_EQ( get<2>(v), 3.15f );
  118. BOOST_TEST_EQ( v4.index(), 2 );
  119. BOOST_TEST_EQ( get<2>(v4), 3.14f );
  120. variant<int, int, float, std::string> v5( "s1" );
  121. BOOST_TEST_EQ( v5.index(), 3 );
  122. BOOST_TEST_EQ( get<3>(v5), std::string("s1") );
  123. swap( v, v5 );
  124. BOOST_TEST_EQ( v.index(), 3 );
  125. BOOST_TEST_EQ( get<3>(v), std::string("s1") );
  126. BOOST_TEST_EQ( v5.index(), 2 );
  127. BOOST_TEST_EQ( get<2>(v5), 3.15f );
  128. variant<int, int, float, std::string> v6( "s2" );
  129. BOOST_TEST_EQ( v6.index(), 3 );
  130. BOOST_TEST_EQ( get<3>(v6), std::string("s2") );
  131. swap( v, v6 );
  132. BOOST_TEST_EQ( v.index(), 3 );
  133. BOOST_TEST_EQ( get<3>(v), std::string("s2") );
  134. BOOST_TEST_EQ( v6.index(), 3 );
  135. BOOST_TEST_EQ( get<3>(v6), std::string("s1") );
  136. }
  137. {
  138. variant<X1, X2> v;
  139. BOOST_TEST_EQ( v.index(), 0 );
  140. BOOST_TEST_EQ( get<0>(v).v, 0 );
  141. variant<X1, X2> v2( X1{1} );
  142. BOOST_TEST_EQ( v2.index(), 0 );
  143. BOOST_TEST_EQ( get<0>(v2).v, 1 );
  144. swap( v, v2 );
  145. BOOST_TEST_EQ( v.index(), 0 );
  146. BOOST_TEST_EQ( get<0>(v).v, 1 );
  147. BOOST_TEST_EQ( v2.index(), 0 );
  148. BOOST_TEST_EQ( get<0>(v2).v, 0 );
  149. variant<X1, X2> v3( in_place_index_t<1>{}, 2 );
  150. BOOST_TEST_EQ( v3.index(), 1 );
  151. BOOST_TEST_EQ( get<1>(v3).v, 2 );
  152. swap( v, v3 );
  153. BOOST_TEST_EQ( v.index(), 1 );
  154. BOOST_TEST_EQ( get<1>(v).v, 2 );
  155. BOOST_TEST_EQ( v3.index(), 0 );
  156. BOOST_TEST_EQ( get<0>(v3).v, 1 );
  157. variant<X1, X2> v4( in_place_index_t<1>{}, 3 );
  158. BOOST_TEST_EQ( v4.index(), 1 );
  159. BOOST_TEST_EQ( get<1>(v4).v, 3 );
  160. swap( v, v4 );
  161. BOOST_TEST_EQ( v.index(), 1 );
  162. BOOST_TEST_EQ( get<1>(v).v, 3 );
  163. BOOST_TEST_EQ( v4.index(), 1 );
  164. BOOST_TEST_EQ( get<1>(v4).v, 2 );
  165. variant<X1, X2> v5( in_place_index_t<0>{}, 4 );
  166. BOOST_TEST_EQ( v5.index(), 0 );
  167. BOOST_TEST_EQ( get<0>(v5).v, 4 );
  168. swap( v, v5 );
  169. BOOST_TEST_EQ( v.index(), 0 );
  170. BOOST_TEST_EQ( get<0>(v).v, 4 );
  171. BOOST_TEST_EQ( v5.index(), 1 );
  172. BOOST_TEST_EQ( get<1>(v5).v, 3 );
  173. }
  174. return boost::report_errors();
  175. }