libstdc++-v3/testsuite/21_strings/basic_string/cons/char/constexpr.cc

   1 // { dg-do compile { target c++20 } }
   2 // { dg-require-effective-target cxx11_abi }
   3
   4 #include <string>
   5
   6 #ifndef __cpp_lib_constexpr_string
   7 # error "Feature-test macro for constexpr std::string missing in <string>"
   8 #elif __cpp_lib_constexpr_string != 201907L
   9 # error "Feature-test macro for constexpr std::string has wrong value in <string>"
  10 #endif
  11
  12 #include <testsuite_hooks.h>
  13
  14 using C = char;
  15 using T = std::char_traits<C>;
  16
  17 template<typename T>
  18 struct Alloc : std::allocator<T>
  19 {
  20   using std::allocator<T>::allocator;
  21
  22   constexpr explicit Alloc(int p) : personality(p) { }
  23
  24   template<typename U>
  25     constexpr Alloc(const Alloc<U>& a) : personality(a.personality) { }
  26
  27   int personality = 0;
  28
  29   constexpr Alloc select_on_container_copy_construction() const
  30   { return Alloc(-1); }
  31
  32   constexpr bool operator==(const Alloc& a) const noexcept
  33   { return personality == a.personality; }
  34 };
  35
  36 constexpr bool
  37 test_default_ctor()
  38 {
  39   std::basic_string<C> s0;
  40   VERIFY( s0.empty() );
  41
  42   std::basic_string<C> s1(std::allocator<C>{});
  43   VERIFY( s1.empty() );
  44
  45   std::basic_string<C, T, Alloc<C>> s2;
  46   VERIFY( s2.empty() );
  47
  48   std::basic_string<C, T, Alloc<C>> s3(Alloc<C>(3));
  49   VERIFY( s3.empty() );
  50   VERIFY( s3.get_allocator().personality == 3 );
  51
  52   return true;
  53 }
  54
  55 static_assert( test_default_ctor() );
  56
  57 constexpr bool
  58 test_cstr()
  59 {
  60   const C cs[] = "This has an embedded \0 null";
  61   const auto len = (sizeof(cs) - 1)/sizeof(C);
  62
  63   std::basic_string<C> s1(cs);
  64   VERIFY( s1.length() == 21 );
  65   std::basic_string<C> s2(cs, std::allocator<C>{});
  66   VERIFY( s2 == s1 );
  67
  68   std::basic_string<C> s3(cs, len);
  69   VERIFY( s3.length() == len );
  70   VERIFY( s3[len] == '\0' );
  71   std::basic_string<C> s4(cs, len, std::allocator<C>{});
  72   VERIFY( s4 == s3 );
  73
  74   std::basic_string<C, T, Alloc<C>> s5(cs);
  75   VERIFY( s5 == std::basic_string_view<C>(s1) );
  76
  77   std::basic_string<C, T, Alloc<C>> s6(cs, Alloc<C>(6));
  78   VERIFY( s6 == std::basic_string_view<C>(s1) );
  79   VERIFY( s6.get_allocator().personality == 6 );
  80
  81   std::basic_string<C, T, Alloc<C>> s7(cs, len, Alloc<C>(7));
  82   VERIFY( s7 == std::basic_string_view<C>(s3) );
  83   VERIFY( s7.get_allocator().personality == 7 );
  84
  85   return true;
  86 }
  87
  88 static_assert( test_cstr() );
  89
  90 constexpr bool
  91 test_copy()
  92 {
  93   const std::basic_string<C> short_string = "sh";
  94   const std::basic_string<C> long_string = "string longer than the SSO buffer";
  95
  96   std::basic_string<C> s1 = short_string;
  97   VERIFY( s1 == short_string );
  98   std::basic_string<C> s2(short_string, s1.get_allocator());
  99   VERIFY( s2 == short_string );
 100
 101   std::basic_string<C> s3 = long_string;
 102   VERIFY( s3 == long_string );
 103   std::basic_string<C> s4(long_string, s1.get_allocator());
 104   VERIFY( s4 == long_string );
 105
 106   std::basic_string<C, T, Alloc<C>> a_short_string = short_string.c_str();
 107   std::basic_string<C, T, Alloc<C>> a_long_string = long_string.c_str();
 108
 109   std::basic_string<C, T, Alloc<C>> s5(a_short_string);
 110   VERIFY( s5 == a_short_string );
 111   std::basic_string<C, T, Alloc<C>> s6(a_short_string, s5.get_allocator());
 112   VERIFY( s6 == a_short_string );
 113   std::basic_string<C, T, Alloc<C>> s7(a_short_string, Alloc<C>(7));
 114   VERIFY( s7 == a_short_string );
 115   VERIFY( s7.get_allocator().personality == 7 );
 116
 117   std::basic_string<C, T, Alloc<C>> s8 = a_long_string;
 118   VERIFY( s8 == a_long_string );
 119   std::basic_string<C, T, Alloc<C>> s9(a_long_string, s5.get_allocator());
 120   VERIFY( s9 == a_long_string );
 121   std::basic_string<C, T, Alloc<C>> s10(a_long_string, Alloc<C>(10));
 122   VERIFY( s10 == a_long_string );
 123   VERIFY( s10.get_allocator().personality == 10 );
 124
 125   return true;
 126 }
 127
 128 static_assert( test_copy() );
 129
 130 constexpr bool
 131 test_move()
 132 {
 133   const std::basic_string<C> short_string = "sh";
 134   const std::basic_string<C> long_string = "string longer than the SSO buffer";
 135
 136   std::basic_string<C> s0 = short_string;
 137
 138   std::basic_string<C> s1 = std::move(s0);
 139   VERIFY( s1 == short_string );
 140   std::basic_string<C> s2(std::move(s1), std::allocator<C>());
 141   VERIFY( s2 == short_string );
 142
 143   s0 = long_string;
 144   std::basic_string<C> s3 = std::move(s0);
 145   VERIFY( s3 == long_string );
 146   std::basic_string<C> s4(std::move(s3), s1.get_allocator());
 147   VERIFY( s4 == long_string );
 148
 149   std::basic_string<C, T, Alloc<C>> a_short_string = short_string.c_str();
 150   std::basic_string<C, T, Alloc<C>> a_long_string = long_string.c_str();
 151
 152   auto sa0 = a_short_string;
 153   std::basic_string<C, T, Alloc<C>> s5 = std::move(sa0);
 154   VERIFY( s5 == a_short_string );
 155   std::basic_string<C, T, Alloc<C>> s6(std::move(s5), sa0.get_allocator());
 156   VERIFY( s6 == a_short_string );
 157   std::basic_string<C, T, Alloc<C>> s7(std::move(s6), Alloc<C>(7));
 158   VERIFY( s7 == a_short_string );
 159   VERIFY( s7.get_allocator().personality == 7 );
 160
 161   sa0 = a_long_string;
 162   std::basic_string<C, T, Alloc<C>> s8 = std::move(sa0);
 163   VERIFY( s8 == a_long_string );
 164   std::basic_string<C, T, Alloc<C>> s9(std::move(s8), s5.get_allocator());
 165   VERIFY( s9 == a_long_string );
 166   std::basic_string<C, T, Alloc<C>> s10(std::move(s9), Alloc<C>(10));
 167   VERIFY( s10 == a_long_string );
 168   VERIFY( s10.get_allocator().personality == 10 );
 169
 170   return true;
 171 }
 172
 173 static_assert( test_move() );