freebsd-src/contrib/libio/ioseekoff.c

55 lines
1.9 KiB
C

/* Copyright (C) 1993, 1997 Free Software Foundation, Inc.
This file is part of the GNU IO 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.
As a special exception, if you link this library with files
compiled with a GNU compiler to produce an executable, this does
not cause the resulting executable to be covered by the GNU General
Public License. This exception does not however invalidate any
other reasons why the executable file might be covered by the GNU
General Public License. */
#include <libioP.h>
_IO_pos_t
_IO_seekoff (fp, offset, dir, mode)
_IO_FILE *fp;
_IO_off_t offset;
int dir;
int mode;
{
_IO_pos_t retval;
/* If we have a backup buffer, get rid of it, since the __seekoff
callback may not know to do the right thing about it.
This may be over-kill, but it'll do for now. TODO */
_IO_cleanup_region_start ((void (*) __P ((void *))) _IO_funlockfile, fp);
_IO_flockfile (fp);
if (_IO_have_backup (fp))
{
if (dir == _IO_seek_cur && _IO_in_backup (fp))
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
_IO_free_backup_area (fp);
}
retval = _IO_SEEKOFF (fp, offset, dir, mode);
_IO_cleanup_region_end (1);
return retval;
}