q.h

用于嵌入式系统的TCP/IP协议栈及若干服务

/*
*            Copyright (c) 1998-2001 by NETsilicon Inc.
*
*  This software is copyrighted by and is the sole property of
*  NETsilicon.  All rights, title, ownership, or other interests
*  in the software remain the property of NETsilicon.  This
*  software may only be used in accordance with the corresponding
*  license agreement.  Any unauthorized use, duplication, transmission,
*  distribution, or disclosure of this software is expressly forbidden.
*
*  This Copyright notice may not be removed or modified without prior
*  written consent of NETsilicon.
*
*  NETsilicon, reserves the right to modify this software
*  without notice.
*
*  NETsilicon
*  411 Waverley Oaks Road                  USA 781.647.1234
*  Suite 227                               http://www.netsilicon.com
*  Waltham, MA 02452                       [e-mail]
*
*************************************************************************
*  $Name: Fusion 6.52 Fusion 6.51 $
*  $Date: 2001/09/20 10:19:23 $
*  $Source: M:/psisrc/stack/incl/rcs/q.h $
*  $Revision: 1.12 $
**************************************************************************
*  File Description:  Definitions and Macros for dealing with `q', `gq'
*                     structures
**************************************************************************/

#ifndef _Q_
#define _Q_

#include "config.h"
#include "ccdep.h"
#include "std.h"

/* basic doubly linked list queue structure */
typedef struct q_t {
	struct q_t      * q_next;
	struct q_t      * q_prev;
} q_t;  /* queue type */

/* Queue structure used all over the kernel */

typedef struct  q {
	struct  q       * q_next;       /* forward link */
	struct  q       * q_prev;       /* backward link */
	u16     q_flags;        /* used for locking, zapping etc. */
	i16     q_parent;       /* offset (in bytes) to parent struct */        
} q;

/* flags for q.q_flags */
#define F_Q_HEADER      0x0001  /* denotes a queue head */
#define F_Q_LOCKED      0x0002  /* don't touch this right now */
#define F_Q_ZAPPED      0x0004  /* this entry awaiting burial */
#define F_Q_PRESERVE    0x0008  /* preserve across unlocks */
#define F_Q_BYTE_QUEUE  0x0800  /* byte-style vs. packet-style queue */

#define is_header(ptr)          bT1(((q *)(ptr))->q_flags,F_Q_HEADER)
#define is_zapped(ptr)          bT1(((q *)(ptr))->q_flags,F_Q_ZAPPED)
#define is_locked(ptr)          bT1(((q *)(ptr))->q_flags,F_Q_LOCKED)
#define q_empty(qp)             (((q *)(qp))->q_next == (q *)(qp))
#define gq_full(gqp)            ((gqp)->gq_cnt >= (gqp)->gq_max)
#define gq_empty(gqp)           ((gqp)->gq_cnt == 0)
#define gq_left(gqp) (((gqp)->gq_max > (gqp)->gq_cnt) ? ((gqp)->gq_max - (gqp)->gq_cnt) : 0)

/* Guarded Queue 'gq' structure used all over the kernel */

typedef struct gq {
	q       gq_q;           /* head and tail links */
    u32     gq_cnt;         /* how many elements are on this queue */
	u32     gq_max;         /* how many elements can be on this queue */
	i16     gq_sleeping;    /* how many procs are sleeping on this queue */
	i16     gq_status;      /* status to be passed up when awakened */
	boolean gq_inuse;		/* indcates whether the queue is presently in service
							   or not */
} gq;


/* internal queue manipulation macros, to be used in critical section */
#define _q_init(qp)     ((qp)->q_next=(qp),(qp)->q_prev=(qp))
#define _q_intail(a,b)  q_in((b), (a))
#define _q_rem(qp)      ((qp)->q_next->q_prev=(qp)->q_prev,(qp)->q_prev->q_next=(qp)->q_next)
#define _q_parent(qp)   (&((char *)(qp))[(qp)->q_parent])
#define _q_outhead(qp)  (q_empty((qp)) ? (char *)0 : q_outparent((qp)->q_next))

/* macro to replace the function q_initparent (performance reasons) */
#define q_initparent(qp,flags,pp) { \
                                    (qp)->q_flags = flags;\
                                    (qp)->q_parent = pp - (char *)(qp);\
                                    _q_init((qp));}

/* macro to replace the function q_init (performance reasons */
#define q_init(qp,flags) { \
                         	(qp)->q_flags = flags; \
	                        _q_init(qp); }

	                      

#endif  /*_Q_*/