libcxx/test/std/containers/views/span.cons/default.pass.cpp

   1 // -*- C++ -*-
   2 //===------------------------------ span ---------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===---------------------------------------------------------------------===//
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // <span>
  12
  13 // constexpr span() noexcept;
  14
  15 #include <span>
  16 #include <cassert>
  17 #include <string>
  18 #include <type_traits>
  19
  20 #include "test_macros.h"
  21
  22 void checkCV()
  23 {
  24 //  Types the same (dynamic sized)
  25     {
  26     std::span<               int> s1;
  27     std::span<const          int> s2;
  28     std::span<      volatile int> s3;
  29     std::span<const volatile int> s4;
  30     assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
  31     }
  32
  33 //  Types the same (static sized)
  34     {
  35     std::span<               int,0> s1;
  36     std::span<const          int,0> s2;
  37     std::span<      volatile int,0> s3;
  38     std::span<const volatile int,0> s4;
  39     assert(s1.size() + s2.size() + s3.size() + s4.size() == 0);
  40     }
  41 }
  42
  43
  44 template <typename T>
  45 constexpr bool testConstexprSpan()
  46 {
  47     std::span<const T>    s1;
  48     std::span<const T, 0> s2;
  49     return
  50         s1.data() == nullptr && s1.size() == 0
  51     &&  s2.data() == nullptr && s2.size() == 0;
  52 }
  53
  54
  55 template <typename T>
  56 void testRuntimeSpan()
  57 {
  58     ASSERT_NOEXCEPT(T{});
  59     std::span<const T>    s1;
  60     std::span<const T, 0> s2;
  61     assert(s1.data() == nullptr && s1.size() == 0);
  62     assert(s2.data() == nullptr && s2.size() == 0);
  63 }
  64
  65
  66 struct A{};
  67
  68 int main(int, char**)
  69 {
  70     static_assert(testConstexprSpan<int>(),    "");
  71     static_assert(testConstexprSpan<long>(),   "");
  72     static_assert(testConstexprSpan<double>(), "");
  73     static_assert(testConstexprSpan<A>(),      "");
  74
  75     testRuntimeSpan<int>();
  76     testRuntimeSpan<long>();
  77     testRuntimeSpan<double>();
  78     testRuntimeSpan<std::string>();
  79     testRuntimeSpan<A>();
  80
  81     checkCV();
  82
  83     static_assert( std::is_default_constructible_v<std::span<int, std::dynamic_extent>>, "");
  84     static_assert( std::is_default_constructible_v<std::span<int, 0>>, "");
  85     static_assert(!std::is_default_constructible_v<std::span<int, 2>>, "");
  86
  87     return 0;
  88 }