#ifndef _THREAD_H_
#define _THREAD_H_ 1
#if defined(__cplusplus)
extern "C" { 
#endif

/* avoid conflicts with socket library */
#undef send
#define send _threadsend
#undef recv
#define recv _threadrecv

typedef struct Alt	Alt;
typedef struct Channel	Channel;
typedef struct Ref	Ref;

/* Channel structure.  S is the size of the buffer.  For unbuffered channels
 * s is zero.  v is an array of s values.  If s is zero, v is unused.
 * f and n represent the state of the queue pointed to by v.
 */

enum {
	Nqwds = 2,
	Nqshift = 5,	// 2log #of bits in long
	Nqmask =  - 1,
	Nqbits = (1 << Nqshift) * 2,
};

struct Channel {
	int			s;		// Size of the channel (may be zero)
	unsigned int	f;		// Extraction point (insertion pt: (f + n) % s)
	unsigned int	n;		// Number of values in the channel
	int			e;		// Element size
	int			freed;	// Set when channel is being deleted
	volatile Alt	**qentry;	// Receivers/senders waiting (malloc)
	volatile int	nentry;	// # of entries malloc-ed
	unsigned char		v[1];		// Array of s values in the channel
};


/* Channel operations for alt: */
typedef enum {
	CHANEND,
	CHANSND,
	CHANRCV,
	CHANNOP,
	CHANNOBLK,
} ChanOp;

struct Alt {
	Channel	*c;		/* channel */
	void		*v;		/* pointer to value */
	ChanOp	op;		/* operation */

	/* the next variables are used internally to alt
	 * they need not be initialized
	 */
	Channel	**tag;	/* pointer to rendez-vous tag */
	int		entryno;	/* entry number */
};

struct Ref {
	Lock lk;
	long ref;
};

int		alt(Alt alts[]);
Channel*	chancreate(int elemsize, int bufsize);
int		chaninit(Channel *c, int elemsize, int elemcnt);
void		chanfree(Channel *c);
int		chanprint(Channel *, char *, ...);
long		decref(Ref *r);		/* returns 0 iff value is now zero */
void		incref(Ref *r);
int		nbrecv(Channel *c, void *v);
void*		nbrecvp(Channel *c);
unsigned long		nbrecvul(Channel *c);
int		nbsend(Channel *c, void *v);
int		nbsendp(Channel *c, void *v);
int		nbsendul(Channel *c, unsigned long v);
int		proccreate(void (*f)(void *arg), void *arg, unsigned int stacksize);
int		procrfork(void (*f)(void *arg), void *arg, unsigned int stacksize, int flag);
void**		procdata(void);
void		procexec(Channel *, int[3], char *, char *[]);
void		procexecl(Channel *, int[3], char *, ...);
int		recv(Channel *c, void *v);
void*		recvp(Channel *c);
unsigned long		recvul(Channel *c);
int		send(Channel *c, void *v);
int		sendp(Channel *c, void *v);
int		sendul(Channel *c, unsigned long v);
int		threadcreate(void (*f)(void *arg), void *arg, unsigned int stacksize);
int		threadcreateidle(void (*f)(void*), void*, unsigned int);
void**		threaddata(void);
void		threadexits(char *);
void		threadexitsall(char *);
int		threadgetgrp(void);	/* return thread group of current thread */
char*		threadgetname(void);
void		threadint(int);	/* interrupt thread */
void		threadintgrp(int);	/* interrupt threads in grp */
void		threadkill(int);	/* kill thread */
void		threadkillgrp(int);	/* kill threads in group */
void		threadmain(int argc, char *argv[]);
void		threadnonotes(void);
int		threadnotify(int (*f)(void*, char*), int in);
int		threadid(void);
int		threadpid(int);
int		threadsetgrp(int);	/* set thread group, return old */
void		threadsetname(char *name);
Channel*	threadwaitchan(void);
int	tprivalloc(void);
void	tprivfree(int);
void	**tprivaddr(int);
void		yield(void);

long		threadstack(void);

extern	int		mainstacksize;

/* slave I/O processes */
typedef struct Ioproc Ioproc;

Ioproc*	ioproc(void);
void		closeioproc(Ioproc*);
void		iointerrupt(Ioproc*);

int		ioclose(Ioproc*, int);
int		iodial(Ioproc*, char*, char*, char*, int*);
int		ioopen(Ioproc*, char*, int);
long		ioread(Ioproc*, int, void*, long);
long		ioreadn(Ioproc*, int, void*, long);
long		iowrite(Ioproc*, int, void*, long);
int		iosleep(Ioproc*, long);

long		iocall(Ioproc*, long (*)(va_list*), ...);
void		ioret(Ioproc*, int);

#if defined(__cplusplus)
}
#endif
#endif	/* _THREADH_ */