libcxx/test/std/ranges/range.factories/range.iota.view/ctor.value.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 explicit iota_view(W value);
  12
  13 #include <cassert>
  14 #include <ranges>
  15 #include <type_traits>
  16
  17 #include "test_macros.h"
  18 #include "types.h"
  19
  20 struct SomeIntComparable {
  21   using difference_type = int;
  22
  23   SomeInt value_;
  24   constexpr SomeIntComparable() : value_(SomeInt(10)) {}
  25
  26   friend constexpr bool operator==(SomeIntComparable lhs, SomeIntComparable rhs) {
  27     return lhs.value_ == rhs.value_;
  28   }
  29   friend constexpr bool operator==(SomeIntComparable lhs, SomeInt rhs) {
  30     return lhs.value_ == rhs;
  31   }
  32   friend constexpr bool operator==(SomeInt lhs, SomeIntComparable rhs) {
  33     return lhs == rhs.value_;
  34   }
  35
  36   friend constexpr difference_type operator-(SomeIntComparable lhs, SomeIntComparable rhs) {
  37     return lhs.value_ - rhs.value_;
  38   }
  39
  40   constexpr SomeIntComparable& operator++() { ++value_; return *this; }
  41   constexpr SomeIntComparable  operator++(int) { auto tmp = *this; ++value_; return tmp; }
  42   constexpr SomeIntComparable  operator--() { --value_; return *this; }
  43 };
  44
  45 constexpr bool test() {
  46   {
  47     std::ranges::iota_view<SomeInt> io(SomeInt(42));
  48     assert((*io.begin()).value_ == 42);
  49     // Check that end returns std::unreachable_sentinel.
  50     assert(io.end() != io.begin());
  51     static_assert(std::same_as<decltype(io.end()), std::unreachable_sentinel_t>);
  52   }
  53
  54   {
  55     std::ranges::iota_view<SomeInt, SomeIntComparable> io(SomeInt(0));
  56     assert(std::ranges::next(io.begin(), 10) == io.end());
  57   }
  58   {
  59     static_assert(!std::is_convertible_v<std::ranges::iota_view<SomeInt>, SomeInt>);
  60     static_assert( std::is_constructible_v<std::ranges::iota_view<SomeInt>, SomeInt>);
  61   }
  62
  63   return true;
  64 }
  65
  66 int main(int, char**) {
  67   test();
  68   static_assert(test());
  69
  70   return 0;
  71 }