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 // <string_view>
  10
  11 // constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
  12
  13 // Throws: out_of_range if pos > size().
  14 // Effects: Determines the effective length rlen of the string to reference as the smaller of n and size() - pos.
  15 // Returns: basic_string_view(data()+pos, rlen).
  16
  17 #include <string_view>
  18 #include <algorithm>
  19 #include <stdexcept>
  20 #include <cassert>
  21
  22 #include "test_macros.h"
  23
  24 template<typename CharT>
  25 void test1(std::basic_string_view<CharT> sv, size_t n, size_t pos) {
  26     std::basic_string_view<CharT> sv1;
  27 #ifdef TEST_HAS_NO_EXCEPTIONS
  28     if (pos > sv.size())
  29         return ;  // would throw if exceptions were enabled
  30     sv1 = sv.substr(pos, n);
  31 #else
  32     try {
  33         sv1 = sv.substr(pos, n);
  34         assert(pos <= sv.size());
  35     }
  36     catch (const std::out_of_range&) {
  37         assert(pos > sv.size());
  38         return ;
  39     }
  40 #endif
  41     const size_t rlen = std::min(n, sv.size() - pos);
  42     assert (sv1.size() == rlen);
  43     for (size_t i = 0; i < rlen; ++i)
  44         assert(sv[pos+i] == sv1[i]);
  45 }
  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     test ( L"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
  79     test ( L"ABCDE" );
  80     test ( L"a" );
  81     test ( L"" );
  82
  83 #if TEST_STD_VER >= 11
  84     test ( u"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
  85     test ( u"ABCDE" );
  86     test ( u"a" );
  87     test ( u"" );
  88
  89     test ( U"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
  90     test ( U"ABCDE" );
  91     test ( U"a" );
  92     test ( U"" );
  93 #endif
  94
  95 #if TEST_STD_VER > 11
  96     {
  97     constexpr std::string_view sv1 { "ABCDE", 5 };
  98
  99     {
 100     constexpr std::string_view sv2 = sv1.substr ( 0, 3 );
 101     static_assert ( sv2.size() == 3, "" );
 102     static_assert ( sv2[0] == 'A', "" );
 103     static_assert ( sv2[1] == 'B', "" );
 104     static_assert ( sv2[2] == 'C', "" );
 105     }
 106
 107     {
 108     constexpr std::string_view sv2 = sv1.substr ( 3, 0 );
 109     static_assert ( sv2.size() == 0, "" );
 110     }
 111
 112     {
 113     constexpr std::string_view sv2 = sv1.substr ( 3, 3 );
 114     static_assert ( sv2.size() == 2, "" );
 115     static_assert ( sv2[0] == 'D', "" );
 116     static_assert ( sv2[1] == 'E', "" );
 117     }
 118     }
 119 #endif
 120
 121   return 0;
 122 }