libcxx/test/std/strings/basic.string/string.modifiers/string_append/append_range.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, c++20
  10
  11 // template<container-compatible-range<charT> R>
  12 //   constexpr basic_string& append_range(R&& rg); // C++23
  13
  14 #include <string>
  15
  16 #include "../../../../containers/sequences/insert_range_sequence_containers.h"
  17 #include "test_macros.h"
  18
  19 // Tested cases:
  20 // - different kinds of insertions (appending an {empty/one-element/mid-sized/long range} into an
  21 //   {empty/one-element/full} container);
  22 // - an exception is thrown when allocating new elements.
  23
  24 constexpr bool test_constexpr() {
  25   for_all_iterators_and_allocators_constexpr<char, const char*>([]<class Iter, class Sent, class Alloc>() {
  26     test_sequence_append_range<std::basic_string<char, std::char_traits<char>, Alloc>, Iter, Sent>([](auto&& c) {
  27       LIBCPP_ASSERT(c.__invariants());
  28     });
  29   });
  30
  31   return true;
  32 }
  33
  34 int main(int, char**) {
  35   static_assert(test_constraints_append_range<std::basic_string, char, int>());
  36
  37   for_all_iterators_and_allocators<char, const char*>([]<class Iter, class Sent, class Alloc>() {
  38     test_sequence_append_range<std::basic_string<char, std::char_traits<char>, Alloc>, Iter, Sent>([](auto&& c) {
  39       LIBCPP_ASSERT(c.__invariants());
  40     });
  41   });
  42   static_assert(test_constexpr());
  43
  44   { // Check that `append_range` returns a reference to the string.
  45     std::string c;
  46     static_assert(std::is_lvalue_reference_v<decltype(c.append_range(FullContainer_Begin_EmptyRange<char>.input))>);
  47     assert(&c.append_range(FullContainer_Begin_EmptyRange<char>.input) == &c);
  48     assert(&c.append_range(FullContainer_Begin_OneElementRange<char>.input) == &c);
  49     assert(&c.append_range(FullContainer_Begin_MidRange<char>.input) == &c);
  50     assert(&c.append_range(FullContainer_Begin_LongRange<char>.input) == &c);
  51   }
  52
  53   // Note: `test_append_range_exception_safety_throwing_copy` doesn't apply because copying chars cannot throw.
  54   {
  55 #if !defined(TEST_HAS_NO_EXCEPTIONS)
  56     // Note: the input string must be long enough to prevent SSO, otherwise the allocator won't be used.
  57     std::string in(64, 'a');
  58
  59     try {
  60       ThrowingAllocator<char> alloc;
  61
  62       globalMemCounter.reset();
  63       std::basic_string<char, std::char_traits<char>, ThrowingAllocator<char>> c(alloc);
  64       c.append_range(in);
  65       assert(false); // The function call above should throw.
  66
  67     } catch (int) {
  68       assert(globalMemCounter.new_called == globalMemCounter.delete_called);
  69     }
  70 #endif
  71   }
  72
  73   return 0;
  74 }