libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.cmp/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 // <iterator>
  10
  11 // reverse_iterator
  12
  13 // template <RandomAccessIterator Iter1, RandomAccessIterator Iter2>
  14 //   requires HasGreater<Iter1, Iter2>
  15 // bool operator<(const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); // constexpr in C++17
  16
  17 #include <iterator>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21 #include "test_iterators.h"
  22
  23 template <class It>
  24 TEST_CONSTEXPR_CXX17 void test(It l, It r, bool x) {
  25     const std::reverse_iterator<It> r1(l);
  26     const std::reverse_iterator<It> r2(r);
  27     assert((r1 < r2) == x);
  28 }
  29
  30 TEST_CONSTEXPR_CXX17 bool tests() {
  31     const char* s = "1234567890";
  32     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
  33     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s+1), false);
  34     test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s), true);
  35 #if TEST_STD_VER >= 20
  36     test(cpp20_random_access_iterator<const char*>(s), cpp20_random_access_iterator<const char*>(s), false);
  37     test(cpp20_random_access_iterator<const char*>(s), cpp20_random_access_iterator<const char*>(s + 1), false);
  38     test(cpp20_random_access_iterator<const char*>(s + 1), cpp20_random_access_iterator<const char*>(s), true);
  39 #endif
  40     test(s, s, false);
  41     test(s, s+1, false);
  42     test(s+1, s, true);
  43     return true;
  44 }
  45
  46 int main(int, char**) {
  47     tests();
  48 #if TEST_STD_VER > 14
  49     static_assert(tests(), "");
  50 #endif
  51     return 0;
  52 }