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[Patch] Fix write after read on eof.
- From: Paolo Carlini <pcarlini at unitus dot it>
- To: libstdc++ at gcc dot gnu dot org
- Cc: bkoz <bkoz at redhat dot com>
- Date: Wed, 25 Jun 2003 20:21:14 +0200
- Subject: [Patch] Fix write after read on eof.
Hi,
as pointed out by Nathan privately, we fail to deal with this
case: a read 'til eof can be followed by read without the need
for an intervening seek. Fixed thusly.
Tested x86-linux, if nobody objects in the next few hours will
commit together with the accompanying testcase.
Paolo.
//////////
2003-06-25 Paolo Carlini <pcarlini@unitus.it>
Nathan C. Myers <ncm-nospam@cantrip.org>
* include/bits/fstream.tcc (_M_underflow): When the actual
end of file is reached, set 'uncommitted' mode to allow a
next write without an intervening seek (see C++98 27.8.1.1,2
and C89 7.9.5.3).
* testsuite/27_io/basic_filebuf/underflow/char/2.cc: New.
diff -urN libstdc++-v3-curr/include/bits/fstream.tcc libstdc++-v3/include/bits/fstream.tcc
--- libstdc++-v3-curr/include/bits/fstream.tcc 2003-06-23 21:27:42.000000000 +0200
+++ libstdc++-v3/include/bits/fstream.tcc 2003-06-25 18:43:35.000000000 +0200
@@ -215,7 +215,7 @@
{
char* __buf = static_cast<char*>(__builtin_alloca(__buflen));
__elen = _M_file.xsgetn(__buf, __buflen);
-
+
const char* __eend;
char_type* __iend;
codecvt_base::result __r;
@@ -246,7 +246,15 @@
__ret = traits_type::to_int_type(*this->gptr());
if (__bump)
this->gbump(1);
- }
+ }
+ else if (__elen == 0)
+ {
+ // If the actual end of file is reached, set 'uncommitted'
+ // mode, thus allowing an immediate write without an
+ // intervening seek.
+ _M_set_buffer(-1);
+ _M_reading = false;
+ }
}
_M_last_overflowed = false;
return __ret;
diff -urN libstdc++-v3-curr/testsuite/27_io/basic_filebuf/underflow/char/2.cc libstdc++-v3/testsuite/27_io/basic_filebuf/underflow/char/2.cc
--- libstdc++-v3-curr/testsuite/27_io/basic_filebuf/underflow/char/2.cc 1970-01-01 01:00:00.000000000 +0100
+++ libstdc++-v3/testsuite/27_io/basic_filebuf/underflow/char/2.cc 2003-06-25 19:43:45.000000000 +0200
@@ -0,0 +1,48 @@
+// 2003-06-25 Paolo Carlini <pcarlini@unitus.it>
+
+// Copyright (C) 2003 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 2, 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 COPYING. If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// 27.8.1.4 Overridden virtual functions
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+ bool test = true;
+ using namespace std;
+
+ std::filebuf fb_out, fb_in_out;
+
+ fb_out.open("tmp_underflow.tst", ios::out);
+ fb_out.sputc('S');
+ fb_out.sputc('T');
+ fb_out.close();
+
+ fb_in_out.open("tmp_underflow.tst", ios::in | ios::out);
+ while (fb_in_out.sbumpc() != filebuf::traits_type::eof());
+
+ VERIFY( fb_in_out.sputc('x') == 'x' );
+ fb_in_out.close();
+}
+
+int main()
+{
+ test01();
+}