libcxx/test/std/strings/basic.string/string.capacity/resize_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 // <string>
  10
  11 // void resize(size_type n); // constexpr since C++20
  12
  13 #include <string>
  14 #include <stdexcept>
  15 #include <cassert>
  16
  17 #include "test_macros.h"
  18 #include "min_allocator.h"
  19
  20 template <class S>
  21 TEST_CONSTEXPR_CXX20 void test(S s, typename S::size_type n, S expected) {
  22   if (n <= s.max_size()) {
  23     s.resize(n);
  24     LIBCPP_ASSERT(s.__invariants());
  25     assert(s == expected);
  26   }
  27 #ifndef TEST_HAS_NO_EXCEPTIONS
  28   else if (!TEST_IS_CONSTANT_EVALUATED) {
  29     try {
  30       s.resize(n);
  31       assert(false);
  32     } catch (std::length_error&) {
  33       assert(n > s.max_size());
  34     }
  35   }
  36 #endif
  37 }
  38
  39 template <class S>
  40 TEST_CONSTEXPR_CXX20 void test_string() {
  41   test(S(), 0, S());
  42   test(S(), 1, S(1, '\0'));
  43   test(S(), 10, S(10, '\0'));
  44   test(S(), 100, S(100, '\0'));
  45   test(S("12345"), 0, S());
  46   test(S("12345"), 2, S("12"));
  47   test(S("12345"), 5, S("12345"));
  48   test(S("12345"), 15, S("12345\0\0\0\0\0\0\0\0\0\0", 15));
  49   test(S("12345678901234567890123456789012345678901234567890"), 0, S());
  50   test(S("12345678901234567890123456789012345678901234567890"), 10, S("1234567890"));
  51   test(S("12345678901234567890123456789012345678901234567890"),
  52        50,
  53        S("12345678901234567890123456789012345678901234567890"));
  54   test(S("12345678901234567890123456789012345678901234567890"),
  55        60,
  56        S("12345678901234567890123456789012345678901234567890\0\0\0\0\0\0\0\0\0\0", 60));
  57   test(S(), S::npos, S("not going to happen"));
  58 }
  59
  60 TEST_CONSTEXPR_CXX20 bool test() {
  61   test_string<std::string>();
  62 #if TEST_STD_VER >= 11
  63   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();
  64 #endif
  65
  66   return true;
  67 }
  68
  69 int main(int, char**) {
  70   test();
  71 #if TEST_STD_VER > 17
  72   static_assert(test());
  73 #endif
  74
  75   return 0;
  76 }