libcxx/test/std/input.output/file.streams/fstreams/filebuf.assign/nonmember_swap.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 // <fstream>
  10
  11 // template <class charT, class traits = char_traits<charT> >
  12 // class basic_filebuf
  13
  14 // template <class charT, class traits>
  15 // void
  16 // swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);
  17
  18 #include <fstream>
  19 #include <cassert>
  20 #include "test_macros.h"
  21 #include "platform_support.h"
  22
  23 int main(int, char**)
  24 {
  25     std::string temp = get_temp_file_name();
  26     {
  27         std::filebuf f;
  28         assert(f.open(temp.c_str(), std::ios_base::out | std::ios_base::in
  29                                                | std::ios_base::trunc) != 0);
  30         assert(f.is_open());
  31         assert(f.sputn("123", 3) == 3);
  32         f.pubseekoff(1, std::ios_base::beg);
  33         assert(f.sgetc() == '2');
  34         std::filebuf f2;
  35         swap(f2, f);
  36         assert(!f.is_open());
  37         assert(f2.is_open());
  38         assert(f2.sgetc() == '2');
  39     }
  40     std::remove(temp.c_str());
  41
  42     // lhs uses a small buffer, rhs is empty
  43     {
  44         std::filebuf f;
  45         assert(f.open(temp.c_str(), std::ios_base::out | std::ios_base::in
  46                                                | std::ios_base::trunc) != 0);
  47         assert(f.is_open());
  48         assert(f.sputn("123", 3) == 3);
  49         f.pubseekoff(1, std::ios_base::beg);
  50         assert(f.sgetc() == '2');
  51         std::filebuf f2;
  52         swap(f, f2);
  53         assert(!f.is_open());
  54         assert(f2.is_open());
  55         assert(f2.sgetc() == '2');
  56     }
  57     std::remove(temp.c_str());
  58
  59     // neither lhs nor rhs use the small buffer
  60     {
  61         std::string tmpA = get_temp_file_name();
  62         std::string tmpB = get_temp_file_name();
  63
  64         {
  65             // currently the small buffer has size 8
  66             std::ofstream sa(tmpA), sb(tmpB);
  67             sa << "0123456789";
  68             sb << "abcdefghij";
  69         }
  70
  71         std::filebuf f1, f2;
  72         assert(f1.open(tmpA, std::ios_base::in) != 0);
  73         assert(f2.open(tmpB, std::ios_base::in) != 0);
  74         assert(f1.sgetc() == '0');
  75         assert(f2.sgetc() == 'a');
  76
  77         swap(f1, f2);
  78
  79         assert(f1.sgetc() == 'a');
  80         assert(f2.sgetc() == '0');
  81
  82         std::remove(tmpA.c_str());
  83         std::remove(tmpB.c_str());
  84     }
  85
  86 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  87     {
  88         std::wfilebuf f;
  89         assert(f.open(temp.c_str(), std::ios_base::out | std::ios_base::in
  90                                                | std::ios_base::trunc) != 0);
  91         assert(f.is_open());
  92         assert(f.sputn(L"123", 3) == 3);
  93         f.pubseekoff(1, std::ios_base::beg);
  94         assert(f.sgetc() == L'2');
  95         std::wfilebuf f2;
  96         swap(f2, f);
  97         assert(!f.is_open());
  98         assert(f2.is_open());
  99         assert(f2.sgetc() == L'2');
 100     }
 101     std::remove(temp.c_str());
 102 #endif
 103
 104   return 0;
 105 }