glibc/libio/iofopncook.c

/* Copyright (C) 1993, 1995, 1997, 1999 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>
#include <stdio.h>
#include <stdlib.h>


/* Prototyped for local functions.  */
static _IO_ssize_t _IO_cookie_read __P ((register _IO_FILE* fp, void* buf,
					 _IO_ssize_t size));
static _IO_ssize_t _IO_cookie_write __P ((register _IO_FILE* fp,
					  const void* buf, _IO_ssize_t size));
static _IO_off64_t _IO_cookie_seek __P ((_IO_FILE *fp, _IO_off64_t offset,
					 int dir));
static int _IO_cookie_close __P ((_IO_FILE* fp));


static _IO_ssize_t
_IO_cookie_read (fp, buf, size)
     _IO_FILE *fp;
     void *buf;
     _IO_ssize_t size;
{
  struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;

  if (cfile->__io_functions.read == NULL)
    return -1;

  return cfile->__io_functions.read (cfile->__cookie, buf, size);
}

static _IO_ssize_t
_IO_cookie_write (fp, buf, size)
     _IO_FILE *fp;
     const void *buf;
     _IO_ssize_t size;
{
  struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;

  if (cfile->__io_functions.write == NULL)
    return -1;

  return cfile->__io_functions.write (cfile->__cookie, buf, size);
}

static _IO_off64_t
_IO_cookie_seek (fp, offset, dir)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
{
  struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;

  if (cfile->__io_functions.seek == NULL)
    return _IO_pos_BAD;

  return cfile->__io_functions.seek (cfile->__cookie, offset, dir);
}

static int
_IO_cookie_close (fp)
     _IO_FILE *fp;
{
  struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;

  if (cfile->__io_functions.close == NULL)
    return 0;

  return cfile->__io_functions.close (cfile->__cookie);
}


static struct _IO_jump_t _IO_cookie_jumps = {
  JUMP_INIT_DUMMY,
  JUMP_INIT(finish, _IO_file_finish),
  JUMP_INIT(overflow, _IO_file_overflow),
  JUMP_INIT(underflow, _IO_file_underflow),
  JUMP_INIT(uflow, _IO_default_uflow),
  JUMP_INIT(pbackfail, _IO_default_pbackfail),
  JUMP_INIT(xsputn, _IO_file_xsputn),
  JUMP_INIT(xsgetn, _IO_default_xsgetn),
  JUMP_INIT(seekoff, _IO_file_seekoff),
  JUMP_INIT(seekpos, _IO_default_seekpos),
  JUMP_INIT(setbuf, _IO_file_setbuf),
  JUMP_INIT(sync, _IO_file_sync),
  JUMP_INIT(doallocate, _IO_file_doallocate),
  JUMP_INIT(read, _IO_cookie_read),
  JUMP_INIT(write, _IO_cookie_write),
  JUMP_INIT(seek, _IO_cookie_seek),
  JUMP_INIT(close, _IO_cookie_close),
  JUMP_INIT(stat, _IO_default_stat),
  JUMP_INIT(showmanyc, _IO_default_showmanyc),
  JUMP_INIT(imbue, _IO_default_imbue),
};


_IO_FILE *
fopencookie (cookie, mode, io_functions)
     void *cookie;
     const char *mode;
     _IO_cookie_io_functions_t io_functions;
{
  int read_write;
  struct locked_FILE
  {
    struct _IO_cookie_file cfile;
#ifdef _IO_MTSAFE_IO
    _IO_lock_t lock;
#endif
  } *new_f;

  switch (*mode++)
    {
    case 'r':
      read_write = _IO_NO_WRITES;
      break;
    case 'w':
      read_write = _IO_NO_READS;
      break;
    case 'a':
      read_write = _IO_NO_READS|_IO_IS_APPENDING;
      break;
    default:
      return NULL;
  }
  if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
    read_write &= _IO_IS_APPENDING;

  new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
  if (new_f == NULL)
    return NULL;
#ifdef _IO_MTSAFE_IO
  new_f->cfile.__file._lock = &new_f->lock;
#endif

  _IO_init (&new_f->cfile.__file, 0);
  _IO_JUMPS (&new_f->cfile.__file) = &_IO_cookie_jumps;
  new_f->cfile.__cookie = cookie;
  new_f->cfile.__io_functions = io_functions;

  _IO_file_init(&new_f->cfile.__file);

  new_f->cfile.__file._IO_file_flags =
    _IO_mask_flags (&new_f->cfile.__file, read_write,
		    _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);

  /* We use a negative number different from -1 for _fileno to mark that
     this special stream is not associated with a real file, but still has
     to be treated as such.  */
  new_f->cfile.__file._fileno = -2;

  return &new_f->cfile.__file;
}