libcxx/test/std/strings/string.view/string.view.ops/substr.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: !stdlib=libc++ && (c++03 || c++11 || c++14)
  10
  11 // <string_view>
  12
  13 // constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
  14
  15 // Throws: out_of_range if pos > size().
  16 // Effects: Determines the effective length rlen of the string to reference as the smaller of n and size() - pos.
  17 // Returns: basic_string_view(data()+pos, rlen).
  18
  19 #include <string_view>
  20 #include <algorithm>
  21 #include <stdexcept>
  22 #include <cassert>
  23
  24 #include "test_macros.h"
  25
  26 template <typename CharT>
  27 void test1(std::basic_string_view<CharT> sv, std::size_t n, size_t pos) {
  28   std::basic_string_view<CharT> sv1;
  29 #ifdef TEST_HAS_NO_EXCEPTIONS
  30   if (pos > sv.size())
  31     return; // would throw if exceptions were enabled
  32   sv1 = sv.substr(pos, n);
  33 #else
  34   try {
  35     sv1 = sv.substr(pos, n);
  36     assert(pos <= sv.size());
  37   } catch (const std::out_of_range&) {
  38     assert(pos > sv.size());
  39     return;
  40   }
  41 #endif
  42   const std::size_t rlen = std::min(n, sv.size() - pos);
  43   assert(sv1.size() == rlen);
  44   for (std::size_t i = 0; i < rlen; ++i)
  45     assert(sv[pos + i] == sv1[i]);
  46 }
  47
  48 template <typename CharT>
  49 void test(const CharT* s) {
  50   typedef std::basic_string_view<CharT> string_view_t;
  51
  52   string_view_t sv1(s);
  53
  54   test1(sv1, 0, 0);
  55   test1(sv1, 1, 0);
  56   test1(sv1, 20, 0);
  57   test1(sv1, sv1.size(), 0);
  58
  59   test1(sv1, 0, 3);
  60   test1(sv1, 2, 3);
  61   test1(sv1, 100, 3);
  62
  63   test1(sv1, 0, string_view_t::npos);
  64   test1(sv1, 2, string_view_t::npos);
  65   test1(sv1, sv1.size(), string_view_t::npos);
  66
  67   test1(sv1, sv1.size() + 1, 0);
  68   test1(sv1, sv1.size() + 1, 1);
  69   test1(sv1, sv1.size() + 1, string_view_t::npos);
  70 }
  71
  72 int main(int, char**) {
  73   test("ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE");
  74   test("ABCDE");
  75   test("a");
  76   test("");
  77
  78 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  79   test(L"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE");
  80   test(L"ABCDE");
  81   test(L"a");
  82   test(L"");
  83 #endif
  84
  85 #if TEST_STD_VER >= 11
  86   test(u"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE");
  87   test(u"ABCDE");
  88   test(u"a");
  89   test(u"");
  90
  91   test(U"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE");
  92   test(U"ABCDE");
  93   test(U"a");
  94   test(U"");
  95 #endif
  96
  97 #if TEST_STD_VER > 11
  98   {
  99     constexpr std::string_view sv1{"ABCDE", 5};
 100
 101     {
 102       constexpr std::string_view sv2 = sv1.substr(0, 3);
 103       static_assert(sv2.size() == 3, "");
 104       static_assert(sv2[0] == 'A', "");
 105       static_assert(sv2[1] == 'B', "");
 106       static_assert(sv2[2] == 'C', "");
 107     }
 108
 109     {
 110       constexpr std::string_view sv2 = sv1.substr(3, 0);
 111       static_assert(sv2.size() == 0, "");
 112     }
 113
 114     {
 115       constexpr std::string_view sv2 = sv1.substr(3, 3);
 116       static_assert(sv2.size() == 2, "");
 117       static_assert(sv2[0] == 'D', "");
 118       static_assert(sv2[1] == 'E', "");
 119     }
 120   }
 121 #endif
 122
 123   return 0;
 124 }