libstdc++: Do not set eofbit eagerly in operator>>(istream&, char(&)[N])

Similar to the bugs I fixed recently in istream::ignore, we incorrectly
set eofbit too often in operator>>(istream&, string&) and
operator>>(istream&.  char(&)[N]).

We should only set eofbit if we reach EOF but would have kept going
otherwise. If we've already extracted the maximum number of characters
(whether that's because of the buffer size or the istream's width())
then we should not set eofbit.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.tcc
	(operator>>(basic_istream&, basic_string&)): Do not set eofbit
	if extraction stopped after in.width() characters.
	* src/c++98/istream-string.cc (operator>>(istream&, string&)):
	Likewise.
	* include/bits/istream.tcc (__istream_extract): Do not set
	eofbit if extraction stopped after n-1 characters.
	* src/c++98/istream.cc (__istream_extract): Likewise.
	* testsuite/21_strings/basic_string/inserters_extractors/char/13.cc: New test.
	* testsuite/21_strings/basic_string/inserters_extractors/wchar_t/13.cc: New test.
	* testsuite/27_io/basic_istream/extractors_character/char/5.cc: New test.
	* testsuite/27_io/basic_istream/extractors_character/wchar_t/5.cc: New test.
This commit is contained in:
Jonathan Wakely 2020-08-06 19:23:14 +01:00
parent 6a3f3e0872
commit 4e39f563c0
8 changed files with 225 additions and 4 deletions

View File

@ -1518,7 +1518,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
__str.append(__buf, __len);
if (_Traits::eq_int_type(__c, __eof))
if (__extracted < __n && _Traits::eq_int_type(__c, __eof))
__err |= __ios_base::eofbit;
__in.width(0);
}

View File

@ -1023,7 +1023,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
++__extracted;
__c = __sb->snextc();
}
if (_Traits::eq_int_type(__c, __eof))
if (__extracted < __num - 1
&& _Traits::eq_int_type(__c, __eof))
__err |= ios_base::eofbit;
// _GLIBCXX_RESOLVE_LIB_DEFECTS

View File

@ -93,7 +93,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
if (__traits_type::eq_int_type(__c, __eof))
if (__extracted < __n && __traits_type::eq_int_type(__c, __eof))
__err |= ios_base::eofbit;
__in.width(0);
}

View File

@ -261,7 +261,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
if (__traits_type::eq_int_type(__c, __eof))
if (__extracted < __num - 1
&& __traits_type::eq_int_type(__c, __eof))
__err |= ios_base::eofbit;
// _GLIBCXX_RESOLVE_LIB_DEFECTS

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@ -0,0 +1,55 @@
// Copyright (C) 2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-do run }
#include <string>
#include <sstream>
#include <testsuite_hooks.h>
void
test01()
{
const std::string str = "1234";
std::istringstream in(str);
std::string buf;
in.width(4);
in >> buf;
VERIFY( !in.eof() ); // should stop after reading 4 chars
VERIFY( buf == str );
}
struct CT : std::char_traits<char> { };
void
test02()
{
const std::basic_string<char, CT> str = "1234";
std::basic_istringstream<char, CT> in(str);
std::basic_string<char, CT> buf;
in.width(4);
in >> buf;
VERIFY( !in.eof() ); // should stop after reading 4 chars
VERIFY( buf == str );
}
int
main()
{
test01();
test02();
}

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@ -0,0 +1,55 @@
// Copyright (C) 2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-do run }
#include <string>
#include <sstream>
#include <testsuite_hooks.h>
void
test01()
{
const std::wstring str = L"1234";
std::wistringstream in(str);
std::wstring buf;
in.width(4);
in >> buf;
VERIFY( !in.eof() ); // should stop after reading 4 chars
VERIFY( buf == str );
}
struct WT : std::char_traits<wchar_t> { };
void
test02()
{
const std::basic_string<wchar_t, WT> str = L"1234";
std::basic_istringstream<wchar_t, WT> in(str);
std::basic_string<wchar_t, WT> buf;
in.width(4);
in >> buf;
VERIFY( !in.eof() ); // should stop after reading 4 chars
VERIFY( buf == str );
}
int
main()
{
test01();
test02();
}

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@ -0,0 +1,54 @@
// Copyright (C) 2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-do run }
#include <sstream>
#include <testsuite_hooks.h>
void
test01()
{
const std::string str = "1234";
std::istringstream in(str);
char buf[6];
in.width(5);
in >> buf; // stops after reading 4 chars, doesn't reach EOF
VERIFY( !in.eof() );
VERIFY( buf == str );
}
struct CT : std::char_traits<char> { };
void
test02()
{
const std::string str = "1234";
std::basic_istringstream<char, CT> in(str.c_str());
char buf[6];
in.width(5);
in >> buf; // stops after reading 4 chars, doesn't reach EOF
VERIFY( !in.eof() );
VERIFY( buf == str );
}
int
main()
{
test01();
test02();
}

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@ -0,0 +1,54 @@
// Copyright (C) 2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-do run }
#include <sstream>
#include <testsuite_hooks.h>
void
test01()
{
const std::string str = "1234";
std::istringstream in(str);
char buf[6];
in.width(5);
in >> buf; // stops after reading 4 chars, doesn't reach EOF
VERIFY( !in.eof() );
VERIFY( buf == str );
}
struct WT : std::char_traits<wchar_t> { };
void
test02()
{
const std::wstring str = L"1234";
std::basic_istringstream<wchar_t, WT> in(str.c_str());
wchar_t buf[6];
in.width(5);
in >> buf; // stops after reading 4 chars, doesn't reach EOF
VERIFY( !in.eof() );
VERIFY( buf == str );
}
int
main()
{
test01();
test02();
}