/*
 * Asterisk
 * 
 * Mark Spencer <markster@marko.net>
 *
 * Copyright(C) Mark Spencer
 * 
 * Distributed under the terms of the GNU General Public License (GPL) Version 2
 *
 * Scheduler Routines (derived from cheops)
 *
 */

#ifndef _ASTERISK_SCHED_H
#define _ASTERISK_SCHED_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

/*
 * The max number of schedule structs to keep around
 * for use.  Undefine to disable schedule structure
 * caching. (Only disable this on very low memory 
 * machines)
 */
 
#define SCHED_MAX_CACHE 128

struct sched_context;

/* Create a scheduling context */
extern struct sched_context *sched_context_create(void);

void sched_context_destroy(struct sched_context *);

/* 
 * A cheops scheduler callback takes a pointer with callback data and
 * returns a 0 if it should not be run again, or non-zero if it should be
 * rescheduled to run again
 */
typedef int (*ast_sched_cb)(void *data);
#define AST_SCHED_CB(a) ((ast_sched_cb)(a))

/* 
 * Schedule an event to take place at some point in the future.  callback 
 * will be called with data as the argument, when milliseconds into the
 * future (approximately)
 */
extern int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, void *data);

/*
 * Remove this event from being run.  A procedure should not remove its
 * own event, but return 0 instead.
 */
extern int ast_sched_del(struct sched_context *con, int id);

/*
 * Determine the number of seconds until the next outstanding event
 * should take place, and return the number of milliseconds until
 * it needs to be run.  This value is perfect for passing to the poll
 * call.  Returns "-1" if there is nothing there are no scheduled events
 * (and thus the poll should not timeout)
 */
extern int ast_sched_wait(struct sched_context *con);

/*
 * Run the queue, executing all callbacks which need to be performed
 * at this time.  Returns the number of events processed.
 */
extern int ast_sched_runq(struct sched_context *con);

/*
 * Debugging: Dump the contents of the scheduler to stderr
 */
extern void ast_sched_dump(struct sched_context *con);

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif



#endif