libcxx/test/std/strings/string.view/string.view.comparison/less.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: !stdlib=libc++ && (c++03 || c++11 || c++14)
  10
  11 // <string_view>
  12
  13 // template<class charT, class traits>
  14 //   constexpr bool operator<(basic_string_view<charT, traits> lhs, basic_string_view<charT, traits> rhs);
  15 // (plus "sufficient additional overloads" to make implicit conversions work as intended)
  16
  17 #include <string_view>
  18 #include <cassert>
  19 #include <string>
  20
  21 #include "test_macros.h"
  22 #include "constexpr_char_traits.h"
  23 #include "make_string.h"
  24
  25 template <class T>
  26 struct ConvertibleTo {
  27   T t_;
  28   TEST_CONSTEXPR explicit ConvertibleTo(T t) : t_(t) {}
  29   TEST_CONSTEXPR operator T() const { return t_; }
  30 };
  31
  32 template <class SV>
  33 TEST_CONSTEXPR_CXX14 bool test() {
  34   typedef typename SV::value_type CharT;
  35   typedef typename SV::traits_type Traits;
  36
  37   // Test the behavior of the operator, both with and without implicit conversions.
  38   SV v[] = {
  39       SV(MAKE_CSTRING(CharT, "")),
  40       SV(MAKE_CSTRING(CharT, "abc")),
  41       SV(MAKE_CSTRING(CharT, "abcdef")),
  42       SV(MAKE_CSTRING(CharT, "acb")),
  43   };
  44   for (int i = 0; i < 4; ++i) {
  45     for (int j = 0; j < 4; ++j) {
  46       // See http://eel.is/c++draft/string.view#tab:string.view.comparison.overloads
  47       bool expected = (i < j);
  48       assert((v[i] < v[j]) == expected);
  49       assert((v[i].data() < v[j]) == expected);
  50       assert((v[i] < v[j].data()) == expected);
  51       assert((ConvertibleTo<SV>(v[i]) < v[j]) == expected);
  52       assert((v[i] < ConvertibleTo<SV>(v[j])) == expected);
  53
  54       if (!TEST_IS_CONSTANT_EVALUATED || TEST_STD_VER >= 20) {
  55         assert((std::basic_string<CharT, Traits>(v[i]) < v[j]) == expected);
  56         assert((v[i] < std::basic_string<CharT, Traits>(v[j])) == expected);
  57       }
  58     }
  59   }
  60
  61   // Test its behavior with embedded null bytes.
  62   SV abc     = SV(MAKE_CSTRING(CharT, "abc"));
  63   SV abc0def = SV(MAKE_CSTRING(CharT, "abc\0def"), 7);
  64   SV abcdef  = SV(MAKE_CSTRING(CharT, "abcdef"));
  65   assert((abc < abc0def) == true);
  66   assert((abc < abcdef) == true);
  67   assert((abc0def < abc) == false);
  68   assert((abc0def < abcdef) == true);
  69   assert((abcdef < abc) == false);
  70   assert((abcdef < abc0def) == false);
  71
  72   assert((abc.data() < abc0def) == true);
  73   assert((abc0def < abc.data()) == false);
  74
  75   if (!TEST_IS_CONSTANT_EVALUATED || TEST_STD_VER >= 20) {
  76     assert((std::basic_string<CharT, Traits>(abc) < abc0def) == true);
  77     assert((abc0def < std::basic_string<CharT, Traits>(abc)) == false);
  78   }
  79
  80   return true;
  81 }
  82
  83 int main(int, char**) {
  84   test<std::string_view>();
  85 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  86   test<std::wstring_view>();
  87 #endif
  88 #if TEST_STD_VER >= 11
  89   test<std::u16string_view>();
  90   test<std::u32string_view>();
  91 #endif
  92 #if TEST_STD_VER > 14
  93   static_assert(test<std::string_view>(), "");
  94 #  ifndef TEST_HAS_NO_WIDE_CHARACTERS
  95   static_assert(test<std::wstring_view>(), "");
  96 #  endif
  97   static_assert(test<std::u16string_view>(), "");
  98   static_assert(test<std::u32string_view>(), "");
  99 #endif
 100
 101 #if TEST_STD_VER > 11
 102   test<std::basic_string_view<char, constexpr_char_traits<char>>>();
 103   static_assert(test<std::basic_string_view<char, constexpr_char_traits<char>>>(), "");
 104 #endif
 105
 106 #if TEST_STD_VER > 17
 107   test<std::u8string_view>();
 108   static_assert(test<std::u8string_view>());
 109 #endif
 110
 111   return 0;
 112 }