libstdc++-v3/testsuite/26_numerics/midpoint/pointer.cc

   1 // Copyright (C) 2019-2020 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 <numeric>
  22 #include <climits>
  23 #include <testsuite_hooks.h>
  24
  25 const int* p = nullptr;
  26 static_assert(std::is_same_v<decltype(std::midpoint(p, p)), decltype(p)>);
  27 // This is a GNU extension:
  28 static_assert(noexcept(std::midpoint(p, p)));
  29
  30 struct test_type { };
  31 template<typename T> decltype(std::midpoint((T*)0, (T*)0)) try_midpoint(int);
  32 template<typename T> test_type try_midpoint(...);
  33 template<typename T> constexpr bool no_midpoint()
  34 { return std::is_same_v<decltype(try_midpoint<T>()), test_type>; }
  35
  36 static_assert(no_midpoint<void>());
  37 static_assert(no_midpoint<int()>());
  38 static_assert(no_midpoint<int&>());
  39 static_assert(no_midpoint<struct Incomplete>());
  40
  41 constexpr int ca[3] = {};
  42 static_assert( std::midpoint(ca, ca+3) == ca+1 );
  43
  44 void
  45 test01()
  46 {
  47   int a[4];
  48   VERIFY( std::midpoint(a, a) == a );
  49   VERIFY( std::midpoint(a, a+1) == a );
  50   VERIFY( std::midpoint(a, a+2) == a+1 );
  51   VERIFY( std::midpoint(a, a+3) == a+1 );
  52   VERIFY( std::midpoint(a, a+4) == a+2 );
  53   VERIFY( std::midpoint(a+1, a) == a+1 );
  54   VERIFY( std::midpoint(a+2, a) == a+1 );
  55   VERIFY( std::midpoint(a+3, a) == a+2 );
  56   VERIFY( std::midpoint(a+4, a) == a+2 );
  57 }
  58
  59 int main()
  60 {
  61   test01();
  62 }