fstream.tcc (_M_underflow): Do not special case the unbuffered case...

2003-06-09  Paolo Carlini  <pcarlini@unitus.it>

	* include/bits/fstream.tcc (_M_underflow): Do not special
	case the unbuffered case, which really means simply a one char
	get area.
	(basic_filebuf): Initialize _M_buf_size.
	(setbuf): Unbuffered means _M_buf_size == 1, since only
	_M_buf_size - 1 == 0 chars are going to be used for the
	put area and 1 for the get area.
	* include/std/std_streambuf.h (_M_buf_size): Move to basic_filebuf.
	(~basic_streambuf): Tweak.
	(basic_streambuf): Do not initialize _M_buf_size.
	* include/std/std_fstream.h (_M_buf_size): Add from basic_streambuf.
	(~basic_filebuf): Tweak.
	(_M_set_buffer): Tweak, considering that _M_buf_size == 1 is the
	unbuffered situation (i.e., put area pointers NULL).
	* include/bits/streambuf.tcc (sbumpc): Clean up.
	* testsuite/27_io/basic_filebuf/sputbackc/char/1.cc: Split into...
	* testsuite/27_io/basic_filebuf/sputbackc/char/1-in.cc: New.
	* testsuite/27_io/basic_filebuf/sputbackc/char/1-io.cc: New.
	* testsuite/27_io/basic_filebuf/sputbackc/char/1-out.cc: New.
	* testsuite/27_io/basic_filebuf/sputbackc/char/2-in.cc: New.
	* testsuite/27_io/basic_filebuf/sputbackc/char/2-io.cc: New.
	* testsuite/27_io/basic_filebuf/sputbackc/char/2-out.cc: New.

From-SVN: r67686

11 files changed, 620 insertions, 117 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 4cd34f6..1e370c0 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,28 @@
+2003-06-09  Paolo Carlini  <pcarlini@unitus.it>
+
+	* include/bits/fstream.tcc (_M_underflow): Do not special
+	case the unbuffered case, which really means simply a one char
+	get area.
+	(basic_filebuf): Initialize _M_buf_size.
+	(setbuf): Unbuffered means _M_buf_size == 1, since only
+	_M_buf_size - 1 == 0 chars are going to be used for the
+	put area and 1 for the get area.
+	* include/std/std_streambuf.h (_M_buf_size): Move to basic_filebuf.
+	(~basic_streambuf): Tweak.
+	(basic_streambuf): Do not initialize _M_buf_size.
+	* include/std/std_fstream.h (_M_buf_size): Add from basic_streambuf.
+	(~basic_filebuf): Tweak.
+	(_M_set_buffer): Tweak, considering that _M_buf_size == 1 is the
+	unbuffered situation (i.e., put area pointers NULL).
+	* include/bits/streambuf.tcc (sbumpc): Clean up.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/1.cc: Split into...
+	* testsuite/27_io/basic_filebuf/sputbackc/char/1-in.cc: New.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/1-io.cc: New.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/1-out.cc: New.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/2-in.cc: New.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/2-io.cc: New.
+	* testsuite/27_io/basic_filebuf/sputbackc/char/2-out.cc: New.
+
 2003-06-09  Phil Edwards  <pme@gcc.gnu.org>
 
 	* acinclude.m4:  Move all AM_CONDITIONAL calls out.
diff --git a/libstdc++-v3/include/bits/fstream.tcc b/libstdc++-v3/include/bits/fstream.tcc
index a46b478..d988309 100644
--- a/libstdc++-v3/include/bits/fstream.tcc
+++ b/libstdc++-v3/include/bits/fstream.tcc
@@ -71,9 +71,9 @@ namespace std
   template<typename _CharT, typename _Traits>
     basic_filebuf<_CharT, _Traits>::
     basic_filebuf() : __streambuf_type(), _M_file(&_M_lock), 
-    _M_state_cur(__state_type()), _M_state_beg(__state_type()), _M_buf(NULL), 
-    _M_buf_allocated(false),_M_last_overflowed(false), 
-    _M_filepos(0), _M_pback(char_type()), _M_pback_cur_save(0), 
+    _M_state_cur(__state_type()), _M_state_beg(__state_type()),
+    _M_buf(NULL), _M_buf_size(BUFSIZ), _M_buf_allocated(false),
+    _M_last_overflowed(false), _M_filepos(0), _M_pback_cur_save(0), 
     _M_pback_end_save(0), _M_pback_init(false), _M_codecvt(0)
     { 
       this->_M_buf_unified = true; 	  
@@ -193,102 +193,64 @@ namespace std
 	  // fileops happen...
 	  _M_destroy_pback();
 
-	  const size_t __buflen = this->_M_buf_size 
-	                          ? this->_M_buf_size - 1 : 0;
-	  if (__buflen)
-	    {
-	      if (this->_M_in_cur < this->_M_in_end)
-		{
-		  __ret = traits_type::to_int_type(*this->_M_in_cur);
-		  if (__bump)
-		    _M_move_in_cur(1);
-		  return __ret;
-		}
+	  const size_t __buflen = this->_M_buf_size > 1
+	                          ? this->_M_buf_size - 1 : 1;
 
-	      // Sync internal and external buffers.
-	      if (__testout && this->_M_out_beg < this->_M_out_lim)
-		this->overflow();
+	  if (this->_M_in_cur < this->_M_in_end)
+	    {
+	      __ret = traits_type::to_int_type(*this->_M_in_cur);
+	      if (__bump)
+		_M_move_in_cur(1);
+	      return __ret;
+	    }
 
-	      // Get and convert input sequence.
-	      streamsize __elen = 0;
-	      streamsize __ilen = 0;
-	      if (__check_facet(_M_codecvt).always_noconv())
+	  // Sync internal and external buffers.
+	  if (__testout && this->_M_out_beg < this->_M_out_lim)
+	    this->overflow();
+	  
+	  // Get and convert input sequence.
+	  streamsize __elen = 0;
+	  streamsize __ilen = 0;
+	  if (__check_facet(_M_codecvt).always_noconv())
+	    {
+	      __elen = _M_file.xsgetn(reinterpret_cast<char*>(this->_M_in_beg), __buflen);
+	      __ilen = __elen;
+	    }
+	  else
+	    {
+	      char* __buf = static_cast<char*>(__builtin_alloca(__buflen));
+	      __elen = _M_file.xsgetn(__buf, __buflen);
+	      
+	      const char* __eend;
+	      char_type* __iend;
+	      codecvt_base::result __r;
+	      __r = _M_codecvt->in(_M_state_cur, __buf, __buf + __elen, 
+				   __eend, this->_M_in_beg, 
+				   this->_M_in_beg + __buflen, __iend);
+	      if (__r == codecvt_base::ok)
+		__ilen = __iend - this->_M_in_beg;
+	      else if (__r == codecvt_base::noconv)
 		{
-		  __elen = _M_file.xsgetn(reinterpret_cast<char*>(this->_M_in_beg), __buflen);
+		  traits_type::copy(this->_M_in_beg,
+				    reinterpret_cast<char_type*>(__buf), 
+				    __elen);
 		  __ilen = __elen;
 		}
-	      else
+	      else 
 		{
-		  char* __buf = static_cast<char*>(__builtin_alloca(__buflen));
-		  __elen = _M_file.xsgetn(__buf, __buflen);
-		  
-		  const char* __eend;
-		  char_type* __iend;
-		  codecvt_base::result __r;
-		  __r = _M_codecvt->in(_M_state_cur, __buf, __buf + __elen, 
-				       __eend, this->_M_in_beg, 
-				       this->_M_in_beg + __buflen, __iend);
-		  if (__r == codecvt_base::ok)
-		    __ilen = __iend - this->_M_in_beg;
-		  else if (__r == codecvt_base::noconv)
-		    {
-		      traits_type::copy(this->_M_in_beg,
- 					reinterpret_cast<char_type*>(__buf), 
-					__elen);
- 		      __ilen = __elen;
-		    }
-		  else 
-		    {
-		      // Unwind.
-		      __ilen = 0;
-		      _M_file.seekoff(-__elen, ios_base::cur, ios_base::in);
-		    }
+		  // Unwind.
+		  __ilen = 0;
+		  _M_file.seekoff(-__elen, ios_base::cur, ios_base::in);
 		}
-
-	      if (__ilen > 0)
-		{
-		  _M_set_buffer(__ilen);
-		  __ret = traits_type::to_int_type(*this->_M_in_cur);
-		  if (__bump)
-		    _M_move_in_cur(1);
-		}	   	    
 	    }
-	  else
+
+	  if (__ilen > 0)
 	    {
-	      // Unbuffered.
-	      char __buf;
-	      if (_M_file.xsgetn(&__buf, 1) > 0)
-		{
-		  if (__check_facet(_M_codecvt).always_noconv())
-		    {
-		      char_type* __cp = reinterpret_cast<char_type*>(&__buf);
-		      __ret = traits_type::to_int_type(*__cp);
-		    }
-		  else
-		    {
-		      char_type __c;		 
-		      const char* __eend;
-		      char_type* __iend;
-		      codecvt_base::result __r;
-		      __r = _M_codecvt->in(_M_state_cur, &__buf, &__buf + 1, 
-					   __eend, &__c, &__c + 1, __iend);
-		      if (__r == codecvt_base::ok 
-			  || __r == codecvt_base::noconv)
-			__ret = traits_type::to_int_type(__c);
-		    }
-
-		  // Need to put back this extracted character so that
-		  // sgetc will not advance the input stream iff
-		  // underflow, but cannot call pbackfail directly as
-		  // it calls underflow... which leads to a recursive
-		  // showdown.
-		  if (!__bump)
-		    {
-		      _M_create_pback();
-		      *this->_M_in_cur = traits_type::to_char_type(__ret); 
-		    }
-		}
-	    }
+	      _M_set_buffer(__ilen);
+	      __ret = traits_type::to_int_type(*this->_M_in_cur);
+	      if (__bump)
+		_M_move_in_cur(1);
+	    }	   	    
 	}
       _M_last_overflowed = false;	
       return __ret;
@@ -467,7 +429,7 @@ namespace std
     setbuf(char_type* __s, streamsize __n)
     {
       if (!this->is_open() && __s == 0 && __n == 0)
-	this->_M_buf_size = 0;
+	this->_M_buf_size = 1;
       else if (__s && __n > 1)
 	{
 	  // This is implementation-defined behavior, and assumes that
diff --git a/libstdc++-v3/include/bits/streambuf.tcc b/libstdc++-v3/include/bits/streambuf.tcc
index 502645d..5b76c40 100644
--- a/libstdc++-v3/include/bits/streambuf.tcc
+++ b/libstdc++-v3/include/bits/streambuf.tcc
@@ -48,12 +48,8 @@ namespace std
       if (_M_in_cur < _M_in_end)
 	{
 	  char_type __c = *this->_M_in_cur;
+	  _M_move_in_cur(1);
 	  __ret = traits_type::to_int_type(__c);
-	  
-	  if (_M_buf_size)
-	    _M_move_in_cur(1);
-	  else
-	    this->underflow();
 	}
       else 
 	__ret = this->uflow();
diff --git a/libstdc++-v3/include/std/std_fstream.h b/libstdc++-v3/include/std/std_fstream.h
index 77350d0..fe72e9d 100644
--- a/libstdc++-v3/include/std/std_fstream.h
+++ b/libstdc++-v3/include/std/std_fstream.h
@@ -121,6 +121,15 @@ namespace std
       */
       char_type*		_M_buf; 	
 
+      /**
+       *  @if maint
+       *  Actual size of internal buffer. This number is equal to the size
+       *  of the put area + 1 position, reserved for the overflow char of
+       *  a full area.
+       *  @endif
+      */
+      size_t			_M_buf_size;
+
       // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.
       /**
        *  @if maint
@@ -206,6 +215,7 @@ namespace std
       ~basic_filebuf()
       {
 	this->close();
+	_M_buf_size = 0;
 	_M_last_overflowed = false;
       }
 
@@ -429,17 +439,15 @@ namespace std
       {
  	const bool __testin = this->_M_mode & ios_base::in;
  	const bool __testout = this->_M_mode & ios_base::out;
-	if (this->_M_buf_size)
+	
+	if (__testin)
+	  this->setg(this->_M_buf, this->_M_buf, this->_M_buf + __off);
+	if (__testout && this->_M_buf_size > 1)
 	  {
-	    if (__testin)
-	      this->setg(this->_M_buf, this->_M_buf, this->_M_buf + __off);
-	    if (__testout)
-	      {
-		this->setp(this->_M_buf, this->_M_buf + this->_M_buf_size - 1);
-		this->_M_out_lim += __off;
-	      }
-	    _M_filepos = this->_M_buf + __off;
+	    this->setp(this->_M_buf, this->_M_buf + this->_M_buf_size - 1);
+	    this->_M_out_lim += __off;
 	  }
+	_M_filepos = this->_M_buf + __off;
       }
     };
 
diff --git a/libstdc++-v3/include/std/std_streambuf.h b/libstdc++-v3/include/std/std_streambuf.h
index c4159cc..b39ff92 100644
--- a/libstdc++-v3/include/std/std_streambuf.h
+++ b/libstdc++-v3/include/std/std_streambuf.h
@@ -197,15 +197,6 @@ namespace std
 
       /**
        *  @if maint
-       *  Actual size of internal buffer. This number is equal to the size
-       *  of the put area + 1 position, reserved for the overflow char of
-       *  a full area.
-       *  @endif
-      */
-      size_t			_M_buf_size;
-
-      /**
-       *  @if maint
        *  Place to stash in || out || in | out settings for current streambuf.
        *  @endif
       */
@@ -267,7 +258,6 @@ namespace std
       ~basic_streambuf() 
       {
 	_M_buf_unified = false;
-	_M_buf_size = 0;
 	_M_mode = ios_base::openmode(0);
       }
 
@@ -468,8 +458,8 @@ namespace std
       */
       basic_streambuf()
       : _M_in_beg(0), _M_in_cur(0), _M_in_end(0), 
-      _M_out_beg(0), _M_out_cur(0), _M_out_end(0),_M_out_lim(0), 
-      _M_buf_unified(false), _M_buf_size(BUFSIZ), 
+      _M_out_beg(0), _M_out_cur(0), _M_out_end(0),
+      _M_out_lim(0), _M_buf_unified(false), 
       _M_mode(ios_base::openmode(0)),_M_buf_locale(locale()) 
       { }
 
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-in.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-in.cc
new file mode 100644
index 0000000..bd6e205
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-in.cc
@@ -0,0 +1,92 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "sgetc.txt"; // file with data in it
+
+// Test overloaded virtual functions.
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+  typedef std::filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 		traits_type;
+
+  bool 					test = true;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // in
+  {
+    constraint_filebuf fb_01; // in 
+    fb_01.open(name_01, ios::in);
+    VERIFY( !fb_01.write_position() );
+    c1 = fb_01.sbumpc();
+    VERIFY( c1 == '/' );
+    c2 = fb_01.sputbackc('/');
+    VERIFY( c1 == c2 );
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == c2 );
+    fb_01.sbumpc();
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == ' ' );
+    c1 = fb_01.sgetc();
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c2 == 'a' );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == c2 );
+    c3 = fb_01.sgetc();
+    VERIFY( c1 == c3 );
+    fb_01.pubseekoff(5, ios_base::beg, ios_base::in);
+    c1 = fb_01.sgetc();
+    VERIFY( c1 == '0' );
+    fb_01.sbumpc();
+    c1 = fb_01.sbumpc();
+    VERIFY( c1 == '1' );
+    c2 = fb_01.sputbackc('b');
+    VERIFY( c2 == 'b' );
+    fb_01.sbumpc();
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == '1' );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == '7' );
+    VERIFY( !fb_01.write_position() );
+    VERIFY( fb_01.read_position() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-io.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-io.cc
new file mode 100644
index 0000000..fd1708e
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-io.cc
@@ -0,0 +1,99 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "tmp_sputbackc_1io.tst"; // empty file, need to create
+
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 	traits_type;
+  typedef size_t 			size_type;
+
+  bool 					test = true;
+  streamsize 			strmsz_1, strmsz_2;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // in | out
+  {
+    constraint_filebuf fb_01; 
+    fb_01.open(name_01, ios_base::out | ios_base::in | ios_base::trunc);
+    VERIFY( fb_01.write_position() );
+    VERIFY( !fb_01.read_position() );
+    strmsz_1 = fb_01.sputn("racadabras", 10);//"abracadabras or what?"
+    strmsz_2 = fb_01.sputn(", i wanna reach out and", 10);
+    c1 = fb_01.sgetc(); // -1
+    c2 = fb_01.sputbackc('z');
+    strmsz_2 = fb_01.in_avail();
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    VERIFY( c1 != c3 );
+    VERIFY( 1 == strmsz_2 );
+    //test for _in_cur == _in_beg
+    // fb_01._M_out_beg = "bd23456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZracada" etc
+    fb_01.pubseekoff(10, std::ios_base::beg, 
+		   std::ios_base::in | std::ios_base::out);
+    fb_01.sputc('m');
+    strmsz_1 = fb_01.in_avail(); 
+    c1 = fb_01.sgetc(); 
+    fb_01.snextc();
+    c2 = fb_01.sputbackc('z');  
+    strmsz_2 = fb_01.in_avail(); 
+    c3 = fb_01.sgetc();  
+    VERIFY( c1 != c2 );
+    VERIFY( c3 == c2 );
+    VERIFY( c1 != c3 );
+    VERIFY( c2 == 'z' );
+    // test for replacing char with identical one
+    fb_01.snextc();
+    fb_01.sputc('u');
+    fb_01.sputc('v');
+    fb_01.sputc('a');
+    strmsz_1 = fb_01.in_avail();
+    c2 = fb_01.sputbackc('a');
+    strmsz_2 = fb_01.in_avail();
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    VERIFY( strmsz_1 + 1 == strmsz_2 );
+    VERIFY( fb_01.write_position() );
+    VERIFY( fb_01.read_position() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-out.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-out.cc
new file mode 100644
index 0000000..78d3b79
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/1-out.cc
@@ -0,0 +1,70 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "tmp_sputbackc_1out.tst"; // empty file, need to create
+
+// Test overloaded virtual functions.
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+  typedef std::filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 		traits_type;
+
+  bool 					test = true;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // out
+  {
+    constraint_filebuf fb_01; // out
+    fb_01.open(name_01, ios::out | ios::trunc);    
+    VERIFY( fb_01.write_position() );
+    VERIFY( !fb_01.read_position() );
+    c1 = fb_01.sgetc();
+    VERIFY( c1 == traits_type::eof() );
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c2 == traits_type::eof() );
+    fb_01.sbumpc();
+    c1 = fb_01.sbumpc();
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c1 == c2 );
+    VERIFY( fb_01.write_position() );
+    VERIFY( !fb_01.read_position() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-in.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-in.cc
new file mode 100644
index 0000000..5deafbc
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-in.cc
@@ -0,0 +1,92 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "sgetc.txt"; // file with data in it
+
+// Test overloaded virtual functions.
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+  typedef std::filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 		traits_type;
+
+  bool 					test = true;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // in
+  {
+    constraint_filebuf fb_01; // in 
+    fb_01.pubsetbuf(0, 0);
+    fb_01.open(name_01, ios::in);
+    VERIFY( fb_01.unbuffered() );
+    c1 = fb_01.sbumpc();
+    VERIFY( c1 == '/' );
+    c2 = fb_01.sputbackc('/');
+    VERIFY( c1 == c2 );
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == c2 );
+    fb_01.sbumpc();
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == ' ' );
+    c1 = fb_01.sgetc();
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c2 == 'a' );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == c2 );
+    c3 = fb_01.sgetc();
+    VERIFY( c1 == c3 );
+    fb_01.pubseekoff(5, ios_base::beg, ios_base::in);
+    c1 = fb_01.sgetc();
+    VERIFY( c1 == '0' );
+    fb_01.sbumpc();
+    c1 = fb_01.sbumpc();
+    VERIFY( c1 == '1' );
+    c2 = fb_01.sputbackc('b');
+    VERIFY( c2 == 'b' );
+    fb_01.sbumpc();
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == '1' );
+    c3 = fb_01.sbumpc();
+    VERIFY( c3 == '7' );
+    VERIFY( fb_01.unbuffered() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-io.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-io.cc
new file mode 100644
index 0000000..fba4481
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-io.cc
@@ -0,0 +1,98 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "tmp_sputbackc_2io.tst"; // empty file, need to create
+
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 	traits_type;
+  typedef size_t 			size_type;
+
+  bool 					test = true;
+  streamsize 			strmsz_1, strmsz_2;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // in | out
+  {
+    constraint_filebuf fb_01;
+    fb_01.pubsetbuf(0, 0);
+    fb_01.open(name_01, ios_base::out | ios_base::in | ios_base::trunc);
+    VERIFY( fb_01.unbuffered() );
+    strmsz_1 = fb_01.sputn("racadabras", 10);//"abracadabras or what?"
+    strmsz_2 = fb_01.sputn(", i wanna reach out and", 10);
+    c1 = fb_01.sgetc(); // -1
+    c2 = fb_01.sputbackc('z');
+    strmsz_2 = fb_01.in_avail();
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    VERIFY( c1 != c3 );
+    VERIFY( 1 == strmsz_2 );
+    //test for _in_cur == _in_beg
+    // fb_01._M_out_beg = "bd23456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZracada" etc
+    fb_01.pubseekoff(10, std::ios_base::beg, 
+		   std::ios_base::in | std::ios_base::out);
+    fb_01.sputc('m');
+    strmsz_1 = fb_01.in_avail(); 
+    c1 = fb_01.sgetc(); 
+    fb_01.snextc();
+    c2 = fb_01.sputbackc('z');  
+    strmsz_2 = fb_01.in_avail(); 
+    c3 = fb_01.sgetc();  
+    VERIFY( c1 != c2 );
+    VERIFY( c3 == c2 );
+    VERIFY( c1 != c3 );
+    VERIFY( c2 == 'z' );
+    // test for replacing char with identical one
+    fb_01.snextc();
+    fb_01.sputc('u');
+    fb_01.sputc('v');
+    fb_01.sputc('a');
+    strmsz_1 = fb_01.in_avail();
+    c2 = fb_01.sputbackc('a');
+    strmsz_2 = fb_01.in_avail();
+    c3 = fb_01.sgetc();
+    VERIFY( c3 == c2 );
+    VERIFY( strmsz_1 == strmsz_2 );
+    VERIFY( fb_01.unbuffered() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-out.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-out.cc
new file mode 100644
index 0000000..52f041d
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/sputbackc/char/2-out.cc
@@ -0,0 +1,71 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "tmp_sputbackc_2out.tst"; // empty file, need to create
+
+// Test overloaded virtual functions.
+void test01() 
+{
+  using namespace std;
+  using namespace __gnu_cxx_test;
+  typedef std::filebuf::int_type 	int_type;
+  typedef filebuf::traits_type 		traits_type;
+
+  bool 					test = true;
+  int_type 			c1, c2, c3;
+
+  // int_type sputbackc(char_type c)
+  // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+  // otherwise decrements in_cur and returns *gptr()
+
+  // out
+  {
+    constraint_filebuf fb_01; // out
+    fb_01.pubsetbuf(0, 0);
+    fb_01.open(name_01, ios::out | ios::trunc);    
+    VERIFY( fb_01.unbuffered() );
+    VERIFY( !fb_01.read_position() );
+    c1 = fb_01.sgetc();
+    VERIFY( c1 == traits_type::eof() );
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c2 == traits_type::eof() );
+    fb_01.sbumpc();
+    c1 = fb_01.sbumpc();
+    c2 = fb_01.sputbackc('a');
+    VERIFY( c1 == c2 );
+    VERIFY( fb_01.unbuffered() );
+    VERIFY( !fb_01.read_position() );
+  }
+}
+
+main() 
+{
+  test01();
+  return 0;
+}