[v3] libstdc++/29354

[Paolo Carlini <pcarlini at suse dot de>]

Hi,

tested x86-linux, committed mainline and 4_1-branch.

Paolo.

/////////////////
2006-10-06  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/29354
	* include/bits/sstream.tcc (basic_stringbuf<>::seekpos(pos_type,
	ios_base::openmode)): Allow for seek to pos_type(off_type(0))
	when the stream is empty.
	* testsuite/27_io/basic_stringbuf/seekpos/char/29354.cc: New.
	* testsuite/27_io/basic_stringbuf/seekpos/wchar_t/29354.cc: New.

Index: include/bits/sstream.tcc
===================================================================
--- include/bits/sstream.tcc	(revision 117430)
+++ include/bits/sstream.tcc	(working copy)
@@ -206,7 +206,7 @@
       const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
 
       const char_type* __beg = __testin ? this->eback() : this->pbase();
-      if (__beg && (__testin || __testout))
+      if ((__beg || !off_type(__sp)) && (__testin || __testout))
 	{
 	  _M_update_egptr();
 
Index: testsuite/27_io/basic_stringbuf/seekpos/wchar_t/29354.cc
===================================================================
--- testsuite/27_io/basic_stringbuf/seekpos/wchar_t/29354.cc	(revision 0)
+++ testsuite/27_io/basic_stringbuf/seekpos/wchar_t/29354.cc	(revision 0)
@@ -0,0 +1,44 @@
+// Copyright (C) 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+#include <sstream>
+#include <testsuite_hooks.h>
+
+// libstdc++/29354
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+  typedef stringbuf::pos_type pos_type;
+  typedef stringbuf::off_type off_type;
+
+  wstringbuf strb_01(ios_base::out);
+
+  pos_type pt_1 = strb_01.pubseekoff(0, ios_base::cur, ios_base::out);
+  VERIFY( pt_1 == pos_type(off_type(0)) );  
+
+  pos_type pt_2 = strb_01.pubseekpos(pt_1, ios_base::out);
+  VERIFY( pt_2 == pos_type(off_type(0)) );
+}
+
+int
+main()
+{
+  test01();
+  return 0;
+}
Index: testsuite/27_io/basic_stringbuf/seekpos/char/29354.cc
===================================================================
--- testsuite/27_io/basic_stringbuf/seekpos/char/29354.cc	(revision 0)
+++ testsuite/27_io/basic_stringbuf/seekpos/char/29354.cc	(revision 0)
@@ -0,0 +1,44 @@
+// Copyright (C) 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+#include <sstream>
+#include <testsuite_hooks.h>
+
+// libstdc++/29354
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+  typedef stringbuf::pos_type pos_type;
+  typedef stringbuf::off_type off_type;
+
+  stringbuf strb_01(ios_base::out);
+
+  pos_type pt_1 = strb_01.pubseekoff(0, ios_base::cur, ios_base::out);
+  VERIFY( pt_1 == pos_type(off_type(0)) );  
+
+  pos_type pt_2 = strb_01.pubseekpos(pt_1, ios_base::out);
+  VERIFY( pt_2 == pos_type(off_type(0)) );
+}
+
+int
+main()
+{
+  test01();
+  return 0;
+}