libcxx/test/std/strings/string.view/string.view.cons/from_iterator_sentinel.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 // UNSUPPORTED: c++03, c++11, c++14, c++17
   9
  10 // <string_view>
  11
  12 //  template <class It, class End>
  13 //  constexpr basic_string_view(It begin, End end)
  14
  15 #include <string_view>
  16 #include <cassert>
  17 #include <iterator>
  18
  19 #include "make_string.h"
  20 #include "test_iterators.h"
  21
  22 template <class It, class Sentinel, class CharT>
  23 constexpr void test_construction(std::basic_string_view<CharT> val) {
  24   auto sv = std::basic_string_view<CharT>(It(val.data()), Sentinel(It(val.data() + val.size())));
  25   assert(sv.data() == val.data());
  26   assert(sv.size() == val.size());
  27 }
  28
  29 template <class CharT>
  30 constexpr void test_with_char() {
  31   const auto val = MAKE_STRING_VIEW(CharT, "test");
  32   test_construction<CharT*, CharT*>(val);
  33   test_construction<CharT*, const CharT*>(val);
  34   test_construction<const CharT*, CharT*>(val);
  35   test_construction<const CharT*, sized_sentinel<const CharT*>>(val);
  36   test_construction<contiguous_iterator<const CharT*>, contiguous_iterator<const CharT*>>(val);
  37   test_construction<contiguous_iterator<const CharT*>, sized_sentinel<contiguous_iterator<const CharT*>>>(val);
  38 }
  39
  40 constexpr bool test() {
  41   test_with_char<char>();
  42 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  43   test_with_char<wchar_t>();
  44 #endif
  45   test_with_char<char8_t>();
  46   test_with_char<char16_t>();
  47   test_with_char<char32_t>();
  48
  49   return true;
  50 }
  51
  52 #ifndef TEST_HAS_NO_EXCEPTIONS
  53 template <class CharT>
  54 struct ThrowingSentinel {
  55   friend bool operator==(const CharT*, ThrowingSentinel) noexcept { return true; }
  56   friend std::iter_difference_t<const CharT*> operator-(const CharT*, ThrowingSentinel) noexcept { return {}; }
  57   friend std::iter_difference_t<const CharT*> operator-(ThrowingSentinel, const CharT*) { throw 42; }
  58 };
  59
  60 template <class CharT>
  61 void test_throwing() {
  62   auto val = MAKE_STRING_VIEW(CharT, "test");
  63   try {
  64     (void)std::basic_string_view<CharT>(val.data(), ThrowingSentinel<CharT>());
  65     assert(false);
  66   } catch (int i) {
  67     assert(i == 42);
  68   }
  69 }
  70
  71 void test_throwing() {
  72   test_throwing<char>();
  73 #  ifndef TEST_HAS_NO_WIDE_CHARACTERS
  74   test_throwing<wchar_t>();
  75 #  endif
  76   test_throwing<char8_t>();
  77   test_throwing<char16_t>();
  78   test_throwing<char32_t>();
  79 }
  80 #endif
  81
  82 static_assert(std::is_constructible_v<std::string_view, const char*, char*>);
  83 static_assert(std::is_constructible_v<std::string_view, char*, const char*>);
  84 static_assert(!std::is_constructible_v<std::string_view, char*, void*>);               // not a sentinel
  85 static_assert(!std::is_constructible_v<std::string_view, signed char*, signed char*>); // wrong char type
  86 static_assert(!std::is_constructible_v<std::string_view,
  87                                        random_access_iterator<char*>,
  88                                        random_access_iterator<char*>>); // not contiguous
  89 static_assert(std::is_constructible_v<std::string_view, contiguous_iterator<char*>, contiguous_iterator<char*>>);
  90
  91 int main(int, char**) {
  92   test();
  93   static_assert(test());
  94
  95 #ifndef TEST_HAS_NO_EXCEPTIONS
  96   test_throwing();
  97 #endif
  98
  99   return 0;
 100 }