libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-3.cc

   1 // Copyright (C) 2003-2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // 27.8.1.4 Overridden virtual functions
  19
  20 // { dg-require-fileio "" }
  21
  22 #include <locale>
  23 #include <fstream>
  24 #include <testsuite_hooks.h>
  25
  26 class Cvt : public std::codecvt<wchar_t, char, std::mbstate_t>
  27 {
  28 public:
  29   mutable bool unshift_called;
  30
  31   Cvt()
  32   : unshift_called(false)
  33   { }
  34
  35 protected:
  36   bool
  37   do_always_noconv() const throw()
  38   { return false; }
  39
  40   int
  41   do_encoding() const throw()
  42   { return -1; }
  43
  44   std::codecvt_base::result
  45   do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
  46   {
  47     unshift_called = true;
  48     to_next = to;
  49     return std::codecvt_base::ok;
  50   }
  51 };
  52
  53 // libstdc++/12790
  54 // basic_filebuf::seekoff() should call codecvt::unshift(),
  55 // but only if writing
  56 void test01()
  57 {
  58   using namespace std;
  59
  60   const char* name = "tmp_seekoff_12790";
  61
  62   Cvt* cvt = new Cvt;
  63   locale loc(locale::classic(), cvt);
  64
  65   wfilebuf fb;
  66   fb.pubimbue(loc);
  67
  68   fb.open(name, ios_base::out);
  69
  70   VERIFY( !cvt->unshift_called );
  71   fb.pubseekoff(0, ios_base::cur);
  72   VERIFY( !cvt->unshift_called );
  73 }
  74
  75 int main()
  76 {
  77   test01();
  78   return 0;
  79 }