/* -*-C-*-

$Id: uxio.h,v 1.9 2007/01/05 21:19:25 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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 of the License, or (at
your option) any later version.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

*/

#ifndef SCM_UXIO_H
#define SCM_UXIO_H

#include "osio.h"

struct channel
{
  int descriptor;
  enum channel_type type;
  unsigned int internal : 1;
  unsigned int nonblocking : 1;
};

#define MARK_CHANNEL_CLOSED(channel) ((CHANNEL_DESCRIPTOR (channel)) = (-1))
#define CHANNEL_CLOSED_P(channel) ((CHANNEL_DESCRIPTOR (channel)) < 0)
#define CHANNEL_OPEN_P(channel) ((CHANNEL_DESCRIPTOR (channel)) >= 0)
#define CHANNEL_DESCRIPTOR(channel) ((channel_table [(channel)]) . descriptor)
#define CHANNEL_TYPE(channel) ((channel_table [(channel)]) . type)
#define CHANNEL_INTERNAL(channel) ((channel_table [(channel)]) . internal)
#define CHANNEL_NONBLOCKING(channel)					\
  ((channel_table [(channel)]) . nonblocking)

#define MAKE_CHANNEL(descriptor, type, receiver)			\
{									\
  Tchannel MAKE_CHANNEL_temp = (channel_allocate ());			\
  (CHANNEL_DESCRIPTOR (MAKE_CHANNEL_temp)) = (descriptor);		\
  (CHANNEL_TYPE (MAKE_CHANNEL_temp)) = (type);				\
  (CHANNEL_INTERNAL (MAKE_CHANNEL_temp)) = 0;				\
  (CHANNEL_NONBLOCKING (MAKE_CHANNEL_temp)) = 0;			\
  receiver (MAKE_CHANNEL_temp);						\
}

extern struct channel * channel_table;
extern Tchannel EXFUN (channel_allocate, (void));

#endif /* SCM_UXIO_H */
