blast: Upper-case metasyntactic variables in the usage message.

[fwd] / chan.h

/* -*-c-*-
 *
 * $Id: chan.h,v 1.3 2004/04/08 01:36:25 mdw Exp $
 *
 * Channel management
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the `fw' port forwarder.
 *
 * `fw' 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.
 * 
 * `fw' 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 `fw'; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef CHAN_H
#define CHAN_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <mLib/sel.h>

/*----- Magic numbers -----------------------------------------------------*/

#define CHAN_BUFSZ 4096

/*----- Data structures ---------------------------------------------------*/

typedef struct chan {
  unsigned base, len;			/* Base and length of data */
  unsigned f;				/* Various interesting flags */
  void (*func)(void */*p*/);		/* Function to call on closure */
  void *p;				/* Argument to pass function */
  sel_file r, w;			/* Reader and writer selectors */
  char buf[CHAN_BUFSZ];			/* The actual data buffer */
} chan;

#define CHANF_CLOSE 1u			/* Close channel when buffer empty */
#define CHANF_READY 2u			/* The channel destination exists */

/*----- Functions provided ------------------------------------------------*/

/* --- @chan_close@ --- *
 *
 * Arguments:	@chan *c@ = pointer to channel
 *
 * Returns:	---
 *
 * Use:		Closes down a channel prematurely.
 */

extern void chan_close(chan */*c*/);

/* --- @chan_dest@ --- *
 *
 * Arguments:	@chan *c@ = pointer to channel
 *		@int fd@ = destination file descriptor for channel
 *
 * Returns:	---
 *
 * Use:		Sets the channel's destination so it knows where to put
 *		data.
 */

extern void chan_dest(chan */*c*/, int /*fd*/);

/* --- @chan_open@ --- *
 *
 * Arguments:	@chan *c@ = pointer to channel to open
 *		@int from, to@ = source and destination file descriptors
 *		@void (*func)(void *p)@ = function to call on closure
 *		@void *p@ = argument to pass to function
 *
 * Returns:	---
 *
 * Use:		Opens a channel.  Data is copied from the source to the
 *		destination.  The @to@ argument may be @-1@ if the file
 *		descriptor isn't known yet.
 */

extern void chan_open(chan */*c*/, int /*from*/, int /*to*/,
		      void (*/*func*/)(void */*p*/), void */*p*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif