libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/45628-2.cc

   1 // Copyright (C) 2010-2022 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 // { dg-require-fileio "" }
  19
  20 #include <fstream>
  21 #include <testsuite_hooks.h>
  22 #include <testsuite_character.h>
  23
  24 const char name_01[] = "tmp_seekoff_45628.tst";
  25
  26 unsigned underflows, overflows;
  27
  28 class my_filebuf
  29 : public std::basic_filebuf<__gnu_test::pod_uchar>
  30 {
  31   virtual int_type
  32   underflow()
  33   {
  34     ++underflows;
  35     return std::basic_filebuf<__gnu_test::pod_uchar>::underflow();
  36   }
  37   virtual int_type
  38   overflow(int_type c)
  39   {
  40     ++overflows;
  41     return std::basic_filebuf<__gnu_test::pod_uchar>::overflow(c);
  42   }
  43 };
  44
  45 // libstdc++/45628
  46 void test01()
  47 {
  48   using __gnu_test::pod_uchar;
  49   std::locale loc(std::locale::classic(),
  50              new std::codecvt<my_filebuf::traits_type::char_type, char,
  51              my_filebuf::traits_type::state_type>);
  52
  53   my_filebuf::pos_type opos[3], ipos[3];
  54   my_filebuf q;
  55   q.pubimbue(loc);
  56
  57   q.open(name_01, std::ios_base::in | std::ios_base::out
  58          | std::ios_base::trunc);
  59
  60   q.sputc(pod_uchar::from<char>('a'));
  61   opos[0] = q.pubseekoff(0, std::ios_base::cur);
  62   q.sputc(pod_uchar::from<char>('b'));
  63   opos[1] = q.pubseekoff(0, std::ios_base::cur);
  64   q.sputc(pod_uchar::from<char>('c'));
  65   opos[2] = q.pubseekoff(0, std::ios_base::cur);
  66
  67   VERIFY( overflows <= 9 ); // pubseekoff calls overflow twice if converting.
  68   // NB: checking opos==ipos is not very rigorous as long as it flushes, since
  69   // all positions will be at initial state.
  70   q.pubseekoff(0, std::ios_base::beg);
  71
  72   q.sbumpc();
  73   VERIFY( underflows == 1 );
  74
  75   ipos[0] = q.pubseekoff(0, std::ios_base::cur);
  76   VERIFY( ipos[0] == opos[0] );
  77   q.sbumpc();
  78   ipos[1] = q.pubseekoff(0, std::ios_base::cur);
  79   VERIFY( ipos[1] == opos[1] );
  80   q.sbumpc();
  81   ipos[2] = q.pubseekoff(0, std::ios_base::cur);
  82   VERIFY( ipos[2] == opos[2] );
  83
  84   VERIFY( underflows == 1 ); // pubseekoff never flushes get area
  85
  86   // Bonus test: check automatic mode switches.
  87   q.sputc(pod_uchar::from<char>('d'));
  88
  89   q.pubseekpos( ipos[1] );
  90   q.sputc(pod_uchar::from<char>('e'));
  91
  92   VERIFY( my_filebuf::traits_type::eq(
  93                         my_filebuf::traits_type::to_char_type(q.sgetc()),
  94                         pod_uchar::from<char>('d')) );
  95 }
  96
  97 int main()
  98 {
  99   test01();
 100   return 0;
 101 }