/*
 * lwp.h -- prototypes and structures for lightweight processes
 * Copyright (C) 1991-3 Stephen Crane.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, 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
 * Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * author: Stephen Crane, (jsc@doc.ic.ac.uk), Department of Computing,
 * Imperial College of Science, Technology and Medicine, 180 Queen's
 * Gate, London SW7 2BZ, England.
 */
#ifndef _LWP_H_
#define _LWP_H_
#ifdef UCONTEXT
#include <ucontext.h>
#else  /* UCONTEXT */
#include <setjmp.h>
#endif /* UCONTEXT */
#include <sys/time.h>
#include "misc.h"
#define LWP_STACKCHECK	0x1
#define LWP_PRINT	0x2

/* process control block.  do *not* change the position of context */
struct lwpProc {
#ifdef UCONTEXT
    ucontext_t context;		/* context structure */
#else				/* UCONTEXT */
    jmp_buf context;		/* processor context area */
#endif				/* UCONTEXT */
    void *sbtm;			/* bottom of stack attached to it */
    int size;			/* size of stack */
    void (*entry)(void *);	/* entry point */
    int dead;			/* whether the process can be rescheduled */
    int pri;			/* which scheduling queue we're on */
    long runtime;		/* time at which process is restarted */
    int fd;			/* fd we're blocking on */
    int argc;			/* initial arguments */
    char **argv;
    void *ud;			/* user data */
    void *lowmark;		/* start of low buffer around stack */
    void *himark;		/* start of upper buffer around stack */
    char *name;			/* process name and description */
    char *desc;
    int flags;
    struct lwpProc *next;
};

/* queue */
struct lwpQueue {
    struct lwpProc *head;
    struct lwpProc *tail;
};

/* semaphore */
struct lwpSem {
    int count;
    struct lwpQueue q;
    char *name;
};

#define LWP_FD_READ	0x1
#define LWP_FD_WRITE	0x2

#define LWP_MAX_PRIO	8

struct lwpProc *lwpInitSystem(int prio, char **ctxp, int flags);
struct lwpProc *lwpCreate(int prio, void (*)(void *), int size,
			  int flags, char *name, char *desc,
			  int argc, char **argv, void *ud);
void lwpExit(void);
void lwpTerminate(struct lwpProc * p);
void lwpYield(void);
void lwpSleepFd(int fd, int flags);
void lwpSleepUntil(long until);
void lwpWakeupFd(struct lwpProc * p);
void *lwpGetUD(struct lwpProc * p);
void lwpSetUD(struct lwpProc * p, char *ud);
void lwpSetDesc(struct lwpProc * p, char *name, char *desc);
int lwpSetPriority(int prio);
void lwpReschedule(void);

struct lwpSem *lwpCreateSem(char *name, int count);
void lwpSignal(struct lwpSem *);
void lwpWait(struct lwpSem *);
void lwpSelect(void *);
void lwpStatus(struct lwpProc *proc, char *format, ...)
    ATTRIBUTE((format (printf, 2, 3)));

extern struct lwpProc *LwpCurrent;

#include "prototypes.h"		/* must come at end, after defines and typedefs */

#endif /* _LWP_H_ */