re PR libstdc++/6414 (g++ 3.1 tellg() regression within last week)

        PR libstdc++/6414
        * include/bits/fstream.tcc (basic_filebuf::seekoff): Adjust return
        value properly in the trivial case.
        * testsuite/27_io/istream_seeks.cc (test04): Make sure that
        tellg() returns the right value after a read.

From-SVN: r52679

libstdc++-v3/ChangeLog

+2002-04-23  Jason Merrill  <jason@redhat.com>
+
+	PR libstdc++/6414
+	* include/bits/fstream.tcc (basic_filebuf::seekoff): Adjust return
+	value properly in the trivial case.
+	* testsuite/27_io/istream_seeks.cc (test04): Make sure that
+	tellg() returns the right value after a read.
+
 2002-04-23  Hans-Peter Nilsson  <hp@bitrange.com>
 
 	* config/cpu/mmix/bits/cpu_limits.h: New file.

libstdc++-v3/include/bits/fstream.tcc

@@ -567,7 +567,7 @@ namespace std
 	  else
 	    {
 	      __ret = _M_file.seekoff(__off, ios_base::cur, __mode);
-	      __ret += max(_M_out_cur, _M_in_cur) - _M_buf;
+	      __ret += _M_in_cur - _M_filepos;
 	    }
 	}
       _M_last_overflowed = false;	

libstdc++-v3/testsuite/27_io/istream_seeks.cc

@@ -229,7 +229,14 @@ void test04(void)
   VERIFY( pos05 == pos06 + off_type(10) );
   VERIFY( state01 == state02 );
   pos06 = is03.tellg(); 
-  VERIFY( pos05 == pos06 ); 
+  VERIFY( pos05 == pos06 );
+
+  // libstdc++/6414
+  if01.seekg(0, std::ios_base::beg);
+  pos01 = if01.tellg();
+  if01.peek();
+  pos02 = if01.tellg();
+  VERIFY( pos02 == pos01 );
 
 #ifdef DEBUG_ASSERT
   assert(test);