libcxx/test/std/iterators/predef.iterators/counted.iterator/count.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: c++03, c++11, c++14, c++17
  10
  11 // constexpr iter_difference_t<I> count() const noexcept;
  12
  13 #include <iterator>
  14
  15 #include "test_macros.h"
  16 #include "test_iterators.h"
  17
  18 struct InputOrOutputArchetype {
  19   using difference_type = int;
  20
  21   int *ptr;
  22
  23   constexpr int operator*() { return *ptr; }
  24   constexpr void operator++(int) { ++ptr; }
  25   constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }
  26 };
  27
  28 constexpr bool test() {
  29   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
  30
  31   {
  32     std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
  33     for (int i = 8; i != 0; --i, ++iter)
  34       assert(iter.count() == i);
  35
  36     static_assert(noexcept(iter.count()));
  37   }
  38   {
  39     std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);
  40     for (int i = 8; i != 0; --i, ++iter)
  41       assert(iter.count() == i);
  42
  43     static_assert(noexcept(iter.count()));
  44   }
  45   {
  46     std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
  47     for (int i = 8; i != 0; --i, ++iter)
  48       assert(iter.count() == i);
  49   }
  50   {
  51     std::counted_iterator iter(InputOrOutputArchetype{buffer + 2}, 6);
  52     assert(iter.count() == 6);
  53   }
  54
  55   // Const tests.
  56   {
  57     const std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
  58     assert(iter.count() == 8);
  59   }
  60   {
  61     const std::counted_iterator iter(forward_iterator<int*>{buffer + 1}, 7);
  62     assert(iter.count() == 7);
  63   }
  64   {
  65     const std::counted_iterator iter(contiguous_iterator<int*>{buffer + 2}, 6);
  66     assert(iter.count() == 6);
  67   }
  68   {
  69     const std::counted_iterator iter(InputOrOutputArchetype{buffer + 2}, 6);
  70     assert(iter.count() == 6);
  71   }
  72
  73   return true;
  74 }
  75
  76 int main(int, char**) {
  77   test();
  78   static_assert(test());
  79
  80   return 0;
  81 }