libstdc++-v3/testsuite/std/ranges/access/crend.cc

   1 // Copyright (C) 2019-2021 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++2a" }
  19 // { dg-do run { target c++2a } }
  20
  21 #include <ranges>
  22 #include <testsuite_hooks.h>
  23 #include <testsuite_iterators.h>
  24
  25 struct R1
  26 {
  27   int i = 0;
  28   int j = 0;
  29
  30   constexpr const int* rbegin() const { return &i; }
  31   constexpr const int* rend() const { return &i + 1; }
  32   friend constexpr const int* rbegin(const R1&& r) { return &r.j; }
  33   friend constexpr const int* rend(const R1&& r) { return &r.j + 1; }
  34 };
  35
  36 // N.B. this is a lie, rend on an R1 rvalue will return a dangling pointer.
  37 template<> constexpr bool std::ranges::enable_borrowed_range<R1> = true;
  38
  39 void
  40 test01()
  41 {
  42   R1 r;
  43   const R1& c = r;
  44   VERIFY( std::ranges::crend(r) == std::ranges::rend(c) );
  45   VERIFY( std::ranges::crend(c) == std::ranges::rend(c) );
  46   VERIFY( std::ranges::crend(std::move(r)) == std::ranges::rend(c) );
  47   VERIFY( std::ranges::crend(std::move(c)) == std::ranges::rend(c) );
  48 }
  49
  50 struct R2
  51 {
  52   int a[2] = { };
  53   long l[2] = { };
  54
  55   const int* begin() const { return a; }
  56   const int* end() const { return a + 2; }
  57
  58   friend const long* begin(const R2&& r) { return r.l; }
  59   friend const long* end(const R2&& r) { return r.l + 2; }
  60 };
  61
  62 // N.B. this is a lie, rend on an R2 rvalue will return a dangling pointer.
  63 template<> constexpr bool std::ranges::enable_borrowed_range<R2> = true;
  64
  65 void
  66 test02()
  67 {
  68   R2 r;
  69   const R2& c = r;
  70   VERIFY( std::ranges::crend(r) == std::ranges::rend(c) );
  71   VERIFY( std::ranges::crend(c) == std::ranges::rend(c) );
  72   VERIFY( std::ranges::crend(std::move(r)) == std::ranges::rend(std::move(c)) );
  73   VERIFY( std::ranges::crend(std::move(c)) == std::ranges::rend(std::move(c)) );
  74 }
  75
  76 struct R3
  77 {
  78   int i = 0;
  79
  80   const int* rbegin() const noexcept { return &i + 1; }
  81   const long* rend() const noexcept { return nullptr; } // not a sentinel for rbegin()
  82
  83   friend const long* rbegin(const R3&) noexcept { return nullptr; }
  84   friend const int* rend(const R3& r) { return &r.i; }
  85 };
  86
  87 // N.B. this is a lie, rend on an R3 rvalue will return a dangling pointer.
  88 template<> constexpr bool std::ranges::enable_borrowed_range<R3> = true;
  89
  90 void
  91 test03()
  92 {
  93   R3 r;
  94   const R3& c = r;
  95   VERIFY( std::ranges::crend(r) == std::ranges::rend(c) );
  96   static_assert( !noexcept(std::ranges::crend(r)) );
  97   VERIFY( std::ranges::crend(c) == std::ranges::rend(c) );
  98   static_assert( !noexcept(std::ranges::crend(c)) );
  99 }
 100
 101 void
 102 test04()
 103 {
 104   int a[2] = { };
 105   const auto& c = a;
 106   VERIFY( std::ranges::crend(a) == std::ranges::rend(c) );
 107   VERIFY( std::ranges::crend(c) == std::ranges::rend(c) );
 108 }
 109
 110 int
 111 main()
 112 {
 113   test01();
 114   test02();
 115   test03();
 116   test04();
 117 }