libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc

   1 // { dg-do compile { target c++17 } }
   2
   3 // Copyright (C) 2017-2021 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 <string>
  21
  22 template<typename CT>
  23   constexpr bool
  24   test_assign()
  25   {
  26     using char_type = typename CT::char_type;
  27     char_type s1[2] = {};
  28     const char_type s2[2] = {1, 0};
  29     CT::assign(s1[0], s2[0]);
  30     return s1[0] == char_type{1};
  31   }
  32
  33 template<typename CT>
  34   constexpr bool
  35   test_compare()
  36   {
  37     using char_type = typename CT::char_type;
  38     const char_type s1[3] = {1, 2, 3};
  39     const char_type s2[3] = {1, 2, 3};
  40     if (CT::compare(s1, s2, 3) != 0)
  41       return false;
  42     if (CT::compare(s2, s1, 3) != 0)
  43       return false;
  44     if (CT::compare(s1+1, s2, 2) <= 0)
  45       return false;
  46     return true;
  47   }
  48
  49 template<typename CT>
  50   constexpr bool
  51   test_length()
  52   {
  53     using char_type = typename CT::char_type;
  54     const char_type s1[4] = {1, 2, 3, 0};
  55     if (CT::length(s1) != 3)
  56       return false;
  57     if (CT::length(s1+1) != 2)
  58       return false;
  59     return true;
  60   }
  61
  62 template<typename CT>
  63   constexpr bool
  64   test_find()
  65   {
  66     using char_type = typename CT::char_type;
  67     const char_type s1[3] = {1, 2, 3};
  68     if (CT::find(s1, 3, char_type{2}) != s1+1)
  69       return false;
  70     if (CT::find(s1, 3, char_type{4}) != nullptr)
  71       return false;
  72     return true;
  73   }
  74
  75 #ifndef __cpp_lib_constexpr_string
  76 # error Feature-test macro for constexpr char_traits is missing
  77 #elif __cpp_lib_constexpr_string < (__cplusplus == 201703 ? 201611 : 201811)
  78 # error Feature-test macro for constexpr char_traits has the wrong value
  79 #endif
  80
  81 // We also provide this non-standard macro for P0426R1 (and P1032R1 in C++20).
  82 #ifndef __cpp_lib_constexpr_char_traits
  83 # error Feature-test macro for constexpr char_traits is missing
  84 #elif __cpp_lib_constexpr_char_traits != (__cplusplus == 201703 ? 201611 : 201811)
  85 # error Feature-test macro for constexpr char_traits has the wrong value
  86 #endif
  87
  88 static_assert( test_assign<std::char_traits<char>>() );
  89 static_assert( test_compare<std::char_traits<char>>() );
  90 static_assert( test_length<std::char_traits<char>>() );
  91 static_assert( test_find<std::char_traits<char>>() );
  92 #ifdef _GLIBCXX_USE_WCHAR_T
  93 static_assert( test_assign<std::char_traits<wchar_t>>() );
  94 static_assert( test_compare<std::char_traits<wchar_t>>() );
  95 static_assert( test_length<std::char_traits<wchar_t>>() );
  96 static_assert( test_find<std::char_traits<wchar_t>>() );
  97 #endif
  98 #ifdef _GLIBCXX_USE_CHAR8_T
  99 static_assert( test_assign<std::char_traits<char8_t>>() );
 100 static_assert( test_compare<std::char_traits<char8_t>>() );
 101 static_assert( test_length<std::char_traits<char8_t>>() );
 102 static_assert( test_find<std::char_traits<char8_t>>() );
 103 #endif
 104 static_assert( test_assign<std::char_traits<char16_t>>() );
 105 static_assert( test_compare<std::char_traits<char16_t>>() );
 106 static_assert( test_length<std::char_traits<char16_t>>() );
 107 static_assert( test_find<std::char_traits<char16_t>>() );
 108 static_assert( test_assign<std::char_traits<char32_t>>() );
 109 static_assert( test_compare<std::char_traits<char32_t>>() );
 110 static_assert( test_length<std::char_traits<char32_t>>() );
 111 static_assert( test_find<std::char_traits<char32_t>>() );
 112
 113 struct C { unsigned char c; };
 114 constexpr bool operator==(const C& c1, const C& c2) { return c1.c == c2.c; }
 115 constexpr bool operator<(const C& c1, const C& c2) { return c1.c < c2.c; }
 116 static_assert( test_assign<std::char_traits<C>>() );
 117 static_assert( test_compare<std::char_traits<C>>() );
 118 static_assert( test_length<std::char_traits<C>>() );
 119 static_assert( test_find<std::char_traits<C>>() );