2002-04-08 Benjamin Kosnik <bkoz@redhat.com>

	libstdc++/5180
	* include/bits/fstream.tcc (filebuf::seekpos): Fix.
	* include/std/std_fstream.h: Clean.
	* include/bits/ostream.tcc: Remove extraneous variables.
	* include/bits/sstream.tcc (stringbuf::seekoff): Be strict about
	open modes and which modes.
	(stringbuf::seekpos): Same.
	* testsuite/27_io/stringbuf_virtuals.cc: New tests.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@52057 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 109 insertions, 53 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 97de30d917d..64e40fae669 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,14 @@
+2002-04-08  Benjamin Kosnik  <bkoz@redhat.com>
+
+	libstdc++/5180
+	* include/bits/fstream.tcc (filebuf::seekpos): Fix.
+	* include/std/std_fstream.h: Clean.
+	* include/bits/ostream.tcc: Remove extraneous variables.
+	* include/bits/sstream.tcc (stringbuf::seekoff): Be strict about
+	open modes and which modes.
+	(stringbuf::seekpos): Same.
+	* testsuite/27_io/stringbuf_virtuals.cc: New tests.
+	
 2002-04-05  Jonathan Wakely <jw@kayari.org>
 
 	* include/bits/stl_algo.h (unique_copy, __gcd, rotate, rotate_copy,
diff --git a/libstdc++-v3/include/bits/fstream.tcc b/libstdc++-v3/include/bits/fstream.tcc
index 0d0882619e8..0117d57fc4c 100644
--- a/libstdc++-v3/include/bits/fstream.tcc
+++ b/libstdc++-v3/include/bits/fstream.tcc
@@ -560,17 +560,17 @@ namespace std
     seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
     {
       pos_type __ret =  pos_type(off_type(-1)); 
-      bool __testopen = this->is_open();
-      bool __testin = __mode & ios_base::in && _M_mode & ios_base::in;
-      bool __testout = __mode & ios_base::out && _M_mode & ios_base::out;
+      bool __testin = _M_mode & ios_base::in;
+      bool __testout = _M_mode & ios_base::out;
 
       // Should probably do has_facet checks here.
       int __width = use_facet<__codecvt_type>(_M_buf_locale).encoding();
       if (__width < 0)
 	__width = 0;
-      bool __testfail = __off != 0  && __width <= 0;
+      bool __testfail = __off != 0 && __width <= 0;
       
-      if (__testopen && !__testfail && (__testin || __testout))
+      if (this->is_open() && !__testfail 
+	  && __mode & _M_mode && (__testin || __testout))
 	{
 	  // Ditch any pback buffers to avoid confusion.
 	  _M_pback_destroy();
@@ -615,13 +615,10 @@ namespace std
     basic_filebuf<_CharT, _Traits>::
     seekpos(pos_type __pos, ios_base::openmode __mode)
     {
-      pos_type __ret;
-      off_type __off = __pos;
-
-      __ret = this->seekoff(__off, ios_base::beg, __mode); 
-
-      _M_last_overflowed = false;	
-      return __ret;
+#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
+// 171. Strange seekpos() semantics due to joint position
+      return this->seekoff(off_type(__pos), ios_base::beg, __mode);
+#endif
     }
 
   template<typename _CharT, typename _Traits>
diff --git a/libstdc++-v3/include/bits/ostream.tcc b/libstdc++-v3/include/bits/ostream.tcc
index 785df851ec1..5c4799b9caa 100644
--- a/libstdc++-v3/include/bits/ostream.tcc
+++ b/libstdc++-v3/include/bits/ostream.tcc
@@ -419,9 +419,7 @@ namespace std
     basic_ostream<_CharT, _Traits>::tellp()
     {
       pos_type __ret = pos_type(-1);
-      bool __testok = this->fail() != true;
-      
-      if (__testok)
+      if (!this->fail())
 	__ret = this->rdbuf()->pubseekoff(0, ios_base::cur, ios_base::out);
       return __ret;
     }
@@ -431,9 +429,7 @@ namespace std
     basic_ostream<_CharT, _Traits>&
     basic_ostream<_CharT, _Traits>::seekp(pos_type __pos)
     {
-      bool __testok = this->fail() != true;
-      
-      if (__testok)
+      if (!this->fail())
 	{
 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
 // 136.  seekp, seekg setting wrong streams?
@@ -452,9 +448,7 @@ namespace std
     basic_ostream<_CharT, _Traits>::
     seekp(off_type __off, ios_base::seekdir __d)
     {
-      bool __testok = this->fail() != true;
-      
-      if (__testok)
+      if (!this->fail())
 	{
 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
 // 136.  seekp, seekg setting wrong streams?
diff --git a/libstdc++-v3/include/bits/sstream.tcc b/libstdc++-v3/include/bits/sstream.tcc
index f83bb697dcc..6aec6e8558a 100644
--- a/libstdc++-v3/include/bits/sstream.tcc
+++ b/libstdc++-v3/include/bits/sstream.tcc
@@ -124,8 +124,10 @@ namespace std
       bool __testin = __mode & ios_base::in && _M_mode & ios_base::in;
       bool __testout = __mode & ios_base::out && _M_mode & ios_base::out;
       bool __testboth = __testin && __testout && __way != ios_base::cur;
-      
-      if (_M_buf_size && ((__testin != __testout) || __testboth))
+      __testin &= !(__mode & ios_base::out);
+      __testout &= !(__mode & ios_base::in);
+
+      if (_M_buf_size && (__testin || __testout || __testboth))
 	{
 	  char_type* __beg = _M_buf;
 	  char_type* __curi = NULL;
@@ -133,12 +135,12 @@ namespace std
 	  char_type* __endi = NULL;
 	  char_type* __endo = NULL;
 
-	  if (__testin)
+	  if (__testin || __testboth)
 	    {
 	      __curi = this->gptr();
 	      __endi = this->egptr();
 	    }
-	  if (__testout)
+	  if (__testout || __testboth)
 	    {
 	      __curo = this->pptr();
 	      __endo = this->epptr();
@@ -157,13 +159,13 @@ namespace std
 	      __newoffo = __endo - __beg;
 	    }
 
-	  if (__testin
+	  if ((__testin || __testboth)
 	      && __newoffi + __off >= 0 && __endi - __beg >= __newoffi + __off)
 	    {
 	      _M_in_cur = __beg + __newoffi + __off;
 	      __ret = pos_type(__newoffi);
 	    }
-	  if (__testout
+	  if ((__testout || __testboth)
 	      && __newoffo + __off >= 0 && __endo - __beg >= __newoffo + __off)
 	    {
 	      _M_out_cur_move(__newoffo + __off - (_M_out_cur - __beg));
@@ -179,33 +181,44 @@ namespace std
     seekpos(pos_type __sp, ios_base::openmode __mode)
     {
       pos_type __ret =  pos_type(off_type(-1)); 
-      off_type __pos = __sp._M_position();
-      char_type* __beg = NULL;
-      char_type* __end = NULL;
-      bool __testin = __mode & ios_base::in && _M_mode & ios_base::in;
-      bool __testout = __mode & ios_base::out && _M_mode & ios_base::out;
       
-      if (__testin)
-	{
-	  __beg = this->eback();
-	  __end = this->egptr();
-	}
-      if (__testout)
-	{
-	  __beg = this->pbase();
-	  __end = _M_buf + _M_buf_size;
-	}
- 
-      if (0 <= __pos && __pos <= __end - __beg)
+      if (_M_buf_size)
 	{
-	  // Need to set both of these if applicable
-	  if (__testin)
-	    _M_in_cur = _M_in_beg + __pos;
-	  if (__testout)
-	    _M_out_cur_move((__pos) - (_M_out_cur - __beg));
-	  __ret = pos_type(off_type(__pos));
+	  off_type __pos = __sp._M_position();
+	  char_type* __beg = NULL;
+	  char_type* __end = NULL;
+	  bool __testin = __mode & ios_base::in && _M_mode & ios_base::in;
+	  bool __testout = __mode & ios_base::out && _M_mode & ios_base::out;
+	  bool __testboth = __testin && __testout;
+	  __testin &= !(__mode & ios_base::out);
+	  __testout &= !(__mode & ios_base::in);
+	  
+	  // NB: Ordered.
+	  bool __testposi = false;
+	  bool __testposo = false;
+	  if (__testin || __testboth)
+	    {
+	      __beg = this->eback();
+	      __end = this->egptr();
+	      if (0 <= __pos && __pos <= __end - __beg)
+		__testposi = true;
+	    }
+	  if (__testout || __testboth)
+	    {
+	      __beg = this->pbase();
+	      __end = _M_buf + _M_buf_size;
+	      if (0 <= __pos && __pos <= __end - __beg)
+		__testposo = true;
+	    }
+	  if (__testposi || __testposo)
+	    {
+	      if (__testposi)
+		_M_in_cur = _M_in_beg + __pos;
+	      if (__testposo)
+		_M_out_cur_move((__pos) - (_M_out_cur - __beg));
+	      __ret = pos_type(off_type(__pos));
+	    }
 	}
-      
       return __ret;
     }
 
diff --git a/libstdc++-v3/include/std/std_fstream.h b/libstdc++-v3/include/std/std_fstream.h
index c3273b55fd4..c462e7bd188 100644
--- a/libstdc++-v3/include/std/std_fstream.h
+++ b/libstdc++-v3/include/std/std_fstream.h
@@ -306,7 +306,7 @@ namespace std
       void
       open(const char* __s, ios_base::openmode __mode = ios_base::in)
       {
-	if (_M_filebuf.open(__s, __mode | ios_base::in) == NULL)
+	if (!_M_filebuf.open(__s, __mode | ios_base::in))
 	  this->setstate(ios_base::failbit);
       }
 
diff --git a/libstdc++-v3/testsuite/27_io/stringbuf_virtuals.cc b/libstdc++-v3/testsuite/27_io/stringbuf_virtuals.cc
index 7e20164712a..318bb72fa8a 100644
--- a/libstdc++-v3/testsuite/27_io/stringbuf_virtuals.cc
+++ b/libstdc++-v3/testsuite/27_io/stringbuf_virtuals.cc
@@ -1,6 +1,6 @@
 // 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
 
-// Copyright (C) 2001 Free Software Foundation, Inc.
+// Copyright (C) 2001, 2002 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
@@ -38,9 +38,50 @@ void test01()
   VERIFY( std::strncmp(strlit, buf, strlitsize) != 0 );
 }
 
+void test02(std::stringbuf& in, bool pass)
+{
+  using namespace std;
+  typedef streambuf::pos_type pos_type;
+  typedef streambuf::off_type off_type;
+  pos_type bad = pos_type(off_type(-1));
+  pos_type p = 0;
+
+  // seekoff
+  p = in.pubseekoff(0, ios_base::beg, ios_base::in);
+  if (pass)
+    VERIFY( p != bad );
+
+  p = in.pubseekoff(0, ios_base::beg, ios_base::out); 
+  VERIFY( p == bad );
+
+  p = in.pubseekoff(0, ios_base::beg); 
+  VERIFY( p == bad );
+
+
+  // seekpos
+  p = in.pubseekpos(0, ios_base::in);
+  if (pass)
+    VERIFY( p != bad );
+
+  p = in.pubseekpos(0, ios_base::out); 
+  VERIFY( p == bad );
+
+  p = in.pubseekpos(0); 
+  VERIFY( p == bad );
+}
+
 int main() 
 {
+  using namespace std;
   test01();
 
+  // movie star, submarine scientist!
+  stringbuf in1("Hedy Lamarr", ios_base::in);
+  stringbuf in2(ios_base::in);
+  stringbuf in3("", ios_base::in);
+  test02(in1, true);
+  test02(in2, false);
+  test02(in3, false);
+
   return 0;
 }