libcxx/test/std/containers/views/span.obs/size_bytes.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++98, c++03, c++11, c++14, c++17
  10
  11 // <span>
  12
  13 // constexpr size_type size_bytes() const noexcept;
  14 //
  15 //  Effects: Equivalent to: return size() * sizeof(element_type);
  16
  17
  18 #include <span>
  19 #include <cassert>
  20 #include <string>
  21
  22 #include "test_macros.h"
  23
  24
  25 template <typename Span>
  26 constexpr bool testConstexprSpan(Span sp, size_t sz)
  27 {
  28     ASSERT_NOEXCEPT(sp.size_bytes());
  29     return (size_t) sp.size_bytes() == sz * sizeof(typename Span::element_type);
  30 }
  31
  32
  33 template <typename Span>
  34 void testRuntimeSpan(Span sp, size_t sz)
  35 {
  36     ASSERT_NOEXCEPT(sp.size_bytes());
  37     assert((size_t) sp.size_bytes() == sz * sizeof(typename Span::element_type));
  38 }
  39
  40 struct A{};
  41 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
  42           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
  43
  44 int main(int, char**)
  45 {
  46     static_assert(testConstexprSpan(std::span<int>(), 0),            "");
  47     static_assert(testConstexprSpan(std::span<long>(), 0),           "");
  48     static_assert(testConstexprSpan(std::span<double>(), 0),         "");
  49     static_assert(testConstexprSpan(std::span<A>(), 0),              "");
  50     static_assert(testConstexprSpan(std::span<std::string>(), 0),    "");
  51
  52     static_assert(testConstexprSpan(std::span<int, 0>(), 0),         "");
  53     static_assert(testConstexprSpan(std::span<long, 0>(), 0),        "");
  54     static_assert(testConstexprSpan(std::span<double, 0>(), 0),      "");
  55     static_assert(testConstexprSpan(std::span<A, 0>(), 0),           "");
  56     static_assert(testConstexprSpan(std::span<std::string, 0>(), 0), "");
  57
  58     static_assert(testConstexprSpan(std::span<const int>(iArr1, 1), 1),    "");
  59     static_assert(testConstexprSpan(std::span<const int>(iArr1, 2), 2),    "");
  60     static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), 3),    "");
  61     static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 4),    "");
  62     static_assert(testConstexprSpan(std::span<const int>(iArr1, 5), 5),    "");
  63
  64     testRuntimeSpan(std::span<int>        (), 0);
  65     testRuntimeSpan(std::span<long>       (), 0);
  66     testRuntimeSpan(std::span<double>     (), 0);
  67     testRuntimeSpan(std::span<A>          (), 0);
  68     testRuntimeSpan(std::span<std::string>(), 0);
  69
  70     testRuntimeSpan(std::span<int, 0>        (), 0);
  71     testRuntimeSpan(std::span<long, 0>       (), 0);
  72     testRuntimeSpan(std::span<double, 0>     (), 0);
  73     testRuntimeSpan(std::span<A, 0>          (), 0);
  74     testRuntimeSpan(std::span<std::string, 0>(), 0);
  75
  76     testRuntimeSpan(std::span<int>(iArr2, 1), 1);
  77     testRuntimeSpan(std::span<int>(iArr2, 2), 2);
  78     testRuntimeSpan(std::span<int>(iArr2, 3), 3);
  79     testRuntimeSpan(std::span<int>(iArr2, 4), 4);
  80     testRuntimeSpan(std::span<int>(iArr2, 5), 5);
  81
  82     testRuntimeSpan(std::span<int, 1>(iArr2 + 5, 1), 1);
  83     testRuntimeSpan(std::span<int, 2>(iArr2 + 4, 2), 2);
  84     testRuntimeSpan(std::span<int, 3>(iArr2 + 3, 3), 3);
  85     testRuntimeSpan(std::span<int, 4>(iArr2 + 2, 4), 4);
  86     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5), 5);
  87
  88     std::string s;
  89     testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0), 0);
  90     testRuntimeSpan(std::span<std::string>(&s, 1), 1);
  91
  92   return 0;
  93 }