PR libstdc++/9439, PR libstdc++/9425

2003-02-04  Paolo Carlini  <pcarlini@unitus.it>

	PR libstdc++/9439, PR libstdc++/9425
	* config/io/basic_file_stdio.cc
	(__basic_file<char>::seekoff, seekpos): Return -1L if
	fseek fails.
	* include/bits/fstream.tcc (basic_filebuf::seekoff):
	Check _M_file.seekoff return value; always return
	pos_type(off_type(-1)) in case of failure.
	(basic_filebuf::pbackfail): Check this->seekoff return
	value and return traits_type::eof() in case of failure.
	* testsuite/27_io/filebuf_virtuals.cc (test09): Add.

From-SVN: r62408

4 files changed, 62 insertions, 19 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index de954ff..1313e40 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,16 @@
+2003-02-04  Paolo Carlini  <pcarlini@unitus.it>
+	
+	PR libstdc++/9439, PR libstdc++/9425
+	* config/io/basic_file_stdio.cc
+	(__basic_file<char>::seekoff, seekpos): Return -1L if
+	fseek fails.
+	* include/bits/fstream.tcc (basic_filebuf::seekoff):
+	Check _M_file.seekoff return value; always return
+	pos_type(off_type(-1)) in case of failure.
+	(basic_filebuf::pbackfail): Check this->seekoff return
+	value and return traits_type::eof() in case of failure.  
+	* testsuite/27_io/filebuf_virtuals.cc (test09): Add.
+
 2003-02-04  Jerry Quinn  <jlquinn@optonline.net>
 
 	* include/std/std_ostream.h (ostream::_M_write): Declare.	
diff --git a/libstdc++-v3/config/io/basic_file_stdio.cc b/libstdc++-v3/config/io/basic_file_stdio.cc
index e378b66..961523b 100644
--- a/libstdc++-v3/config/io/basic_file_stdio.cc
+++ b/libstdc++-v3/config/io/basic_file_stdio.cc
@@ -203,15 +203,21 @@ namespace std
   __basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way, 
 			      ios_base::openmode /*__mode*/)
   { 
-    fseek(_M_cfile, __off, __way); 
-    return ftell(_M_cfile); 
+    if (!fseek(_M_cfile, __off, __way))
+      return ftell(_M_cfile); 
+    else
+      // Fseek failed.
+      return -1L;
   }
 
   streamoff
   __basic_file<char>::seekpos(streamoff __pos, ios_base::openmode /*__mode*/)
   { 
-    fseek(_M_cfile, __pos, ios_base::beg); 
-    return ftell(_M_cfile); 
+    if (!fseek(_M_cfile, __pos, ios_base::beg))
+      return ftell(_M_cfile);
+    else
+      // Fseek failed.
+      return -1L;
   }
   
   int 
diff --git a/libstdc++-v3/include/bits/fstream.tcc b/libstdc++-v3/include/bits/fstream.tcc
index c5f9758..abc7310 100644
--- a/libstdc++-v3/include/bits/fstream.tcc
+++ b/libstdc++-v3/include/bits/fstream.tcc
@@ -215,19 +215,24 @@ namespace std
 	    {	 
  	      // At the beginning of the buffer, need to make a
 	      // putback position available.
-	      this->seekoff(-1, ios_base::cur);
-	      this->underflow();
- 	      if (!__testeof)
- 		{
-		  if (!traits_type::eq(__c, *this->_M_in_cur))
+	      // But the seek may fail (f.i., at the beginning of
+	      // a file, see libstdc++/9439) and in that case
+	      // we return traits_type::eof()
+	      if (this->seekoff(-1, ios_base::cur) >= 0)
+		{
+		  this->underflow();
+		  if (!__testeof)
 		    {
-		      _M_pback_create();
-		      *this->_M_in_cur = __c;
+		      if (!traits_type::eq(__c, *this->_M_in_cur))
+			{
+			  _M_pback_create();
+			  *this->_M_in_cur = __c;
+			}
+		      __ret = __i;
 		    }
- 		  __ret = __i;
- 		}
- 	      else
- 		__ret = traits_type::not_eof(__i);
+		  else
+		    __ret = traits_type::not_eof(__i);
+		}
  	    }
 	}
       _M_last_overflowed = false;	
@@ -439,7 +444,8 @@ namespace std
 	      //in
 	      else if (__testget && __way == ios_base::cur)
 		__computed_off += this->_M_in_cur - _M_filepos;
-	  
+
+	      // Return pos_type(off_type(-1)) in case of failure.
 	      __ret = _M_file.seekoff(__computed_off, __way, __mode);
 	      _M_set_indeterminate();
 	    }
@@ -447,9 +453,12 @@ namespace std
 	  // state, ie _M_file._offset == -1
 	  else
 	    {
-	      __ret = _M_file.seekoff(__off, ios_base::cur, __mode);
-	      __ret +=
-		std::max(this->_M_out_cur, this->_M_in_cur) - _M_filepos;
+	      pos_type __tmp =
+		_M_file.seekoff(__off, ios_base::cur, __mode);
+	      if (__tmp >= 0)
+		// Seek successful.
+		__ret = __tmp +
+		  std::max(this->_M_out_cur, this->_M_in_cur) - _M_filepos;
 	    }
 	}
       _M_last_overflowed = false;	
diff --git a/libstdc++-v3/testsuite/27_io/filebuf_virtuals.cc b/libstdc++-v3/testsuite/27_io/filebuf_virtuals.cc
index 75c2e1c..58a5650 100644
--- a/libstdc++-v3/testsuite/27_io/filebuf_virtuals.cc
+++ b/libstdc++-v3/testsuite/27_io/filebuf_virtuals.cc
@@ -570,6 +570,20 @@ void test08()
   mb.sputbackc(0);  
 }
 
+// libstdc++/9439, libstdc++/9425
+void test09()
+{
+  using namespace std;
+  bool test = true;
+
+  filebuf fbuf;
+  fbuf.open(name_01, ios_base::in);
+  filebuf::int_type r = fbuf.sputbackc('a');
+  fbuf.close();
+
+  VERIFY( r == filebuf::traits_type::eof() );
+}
+
 main() 
 {
   test01();
@@ -582,5 +596,6 @@ main()
 
   test07();
   test08();
+  test09();
   return 0;
 }