libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/45628-1.cc

   1 // Copyright (C) 2010-2019 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 // { dg-require-fileio "" }
  19
  20 #include <fstream>
  21 #include <testsuite_hooks.h>
  22
  23 const char name_01[] = "tmp_seekoff_45628.tst";
  24
  25 unsigned underflows, overflows;
  26
  27 class my_filebuf
  28 : public std::filebuf
  29 {
  30   virtual int_type
  31   underflow()
  32   {
  33     ++underflows;
  34     return std::filebuf::underflow();
  35   }
  36   virtual int_type
  37   overflow(int_type c)
  38   {
  39     ++overflows;
  40     return std::filebuf::overflow(c);
  41   }
  42 };
  43
  44 // libstdc++/45628
  45 void test01()
  46 {
  47   my_filebuf q;
  48   q.open(name_01, std::ios_base::in | std::ios_base::out
  49          | std::ios_base::trunc);
  50
  51   q.sputc('a');
  52   q.pubseekoff(0, std::ios_base::cur);
  53   q.sputc('b');
  54   q.pubseekoff(0, std::ios_base::cur);
  55   q.sputc('c');
  56   q.pubseekoff(0, std::ios_base::cur);
  57
  58   VERIFY( overflows <= 1 ); // only initial sputc allowed to overflow
  59   q.pubseekoff(0, std::ios_base::beg);
  60
  61   q.sbumpc();
  62   VERIFY( underflows == 1 );
  63
  64   q.pubseekoff(0, std::ios_base::cur);
  65   q.sbumpc();
  66   q.pubseekoff(0, std::ios_base::cur);
  67   q.sbumpc();
  68   q.pubseekoff(0, std::ios_base::cur);
  69
  70   VERIFY( underflows == 1 );
  71 }
  72
  73 int main()
  74 {
  75   test01();
  76   return 0;
  77 }