libcxx/test/std/ranges/range.utility/range.subrange/ctor.range_size.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 // template<borrowed_range R>
  12 //   requires convertible-to-non-slicing<iterator_t<R>, I> &&
  13 //            convertible_to<sentinel_t<R>, S>
  14 // constexpr subrange(R&& r, make-unsigned-like-t<iter_difference_t<I>> n)
  15 //   requires (K == subrange_kind::sized);
  16
  17 #include <ranges>
  18 #include <cassert>
  19
  20 struct BorrowedRange {
  21   constexpr explicit BorrowedRange(int* b, int* e) : begin_(b), end_(e) { }
  22   constexpr int* begin() const { return begin_; }
  23   constexpr int* end() const { return end_; }
  24
  25 private:
  26   int* begin_;
  27   int* end_;
  28 };
  29
  30 template <>
  31 inline constexpr bool std::ranges::enable_borrowed_range<BorrowedRange> = true;
  32
  33 constexpr bool test() {
  34   int buff[] = {1, 2, 3, 4, 5, 6, 7, 8};
  35   using Subrange = std::ranges::subrange<int*, int*, std::ranges::subrange_kind::sized>;
  36
  37   // Test with an empty range
  38   {
  39     BorrowedRange range(buff, buff);
  40     Subrange subrange(range, 0);
  41     assert(subrange.size() == 0);
  42   }
  43
  44   // Test with non-empty ranges
  45   {
  46     BorrowedRange range(buff, buff + 1);
  47     Subrange subrange(range, 1);
  48     assert(subrange.size() == 1);
  49   }
  50   {
  51     BorrowedRange range(buff, buff + 2);
  52     Subrange subrange(range, 2);
  53     assert(subrange[0] == 1);
  54     assert(subrange[1] == 2);
  55     assert(subrange.size() == 2);
  56   }
  57   {
  58     BorrowedRange range(buff, buff + 8);
  59     Subrange subrange(range, 8);
  60     assert(subrange[0] == 1);
  61     assert(subrange[1] == 2);
  62     // ...
  63     assert(subrange[7] == 8);
  64     assert(subrange.size() == 8);
  65   }
  66
  67   return true;
  68 }
  69
  70 int main(int, char**) {
  71   test();
  72   static_assert(test());
  73
  74   return 0;
  75 }