bsd/netat/adsp_TimerElem.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * TimerElem.c
  30  *
  31  * From v01.00  04/15/90 mbs
  32  *    Modified for MP, 1996 by Tuyen Nguyen
  33  *   Modified, April 9, 1997 by Tuyen Nguyen for MacOSX.
  34 */
  35
  36 #include <sys/errno.h>
  37 #include <sys/types.h>
  38 #include <sys/param.h>
  39 #include <machine/spl.h>
  40 #include <sys/systm.h>
  41 #include <sys/kernel.h>
  42 #include <sys/proc.h>
  43 #include <sys/filedesc.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/socket.h>
  47
  48 #include <netat/sysglue.h>
  49 #include <netat/appletalk.h>
  50 #include <netat/at_pcb.h>
  51 #include <netat/debug.h>
  52 #include <netat/adsp.h>
  53 #include <netat/adsp_internal.h>
  54
  55
  56 extern  void DoTimerElem(TimerElemPtr); /* (TimerElemPtr t);
  57                                  * External routine called to
  58                                  * process each one. */
  59
  60 /*
  61  * InsertTimerElem
  62  *
  63  * INPUTS:
  64  *      qhead           Address of ptr to first item in list
  65  *      t               timer element to link in
  66  *      vbl             timer value to use
  67  * OUTPUTS:
  68  *      void
  69  */
  70 void InsertTimerElem(qhead, t, val)
  71     /* (TimerElemPtr *qhead, TimerElemPtr t, word val) */
  72     TimerElemPtr *qhead, t;
  73     int val;
  74 {
  75     TimerElemPtr p;             /* parent pointer */
  76     TimerElemPtr n;             /* current */
  77
  78     if (t->onQ) {
  79         /*
  80                 * someone else beat us to the punch and put this
  81                 * element back on the queue, just return in this case
  82                 */
  83                 return;
  84     }
  85     p = (TimerElemPtr)qhead;
  86
  87     while ((n = p->link)) {
  88         if (val <= n->timer)    /* Do we go in front of this? */
  89         {
  90             n->timer -= val;    /* Yes, adjust his delta */
  91             break;              /* and go link us in */
  92         }
  93         val -= n->timer;        /* No, subtract off delta from our value */
  94         p = n;
  95     }                           /* while */
  96
  97     /* It must go after item pointed to by p and in front of item
  98      * pointed to by n */
  99
 100     t->onQ = 1; /* we're linked in now */
 101     p->link = t;                /* parent points to us */
 102     t->timer = val;             /* this is our value */
 103     t->link = n;                /* we point to n */
 104
 105 }
 106
 107
 108 /*
 109  * RemoveTimerElem
 110  *
 111  * INPUTS:
 112  *      qhead           Address of ptr to first item in list
 113  *      t               timer element to link in
 114  * OUTPUTS:
 115  *      void
 116  */
 117 void RemoveTimerElem(qhead, t)  /* (TimerElemPtr *qhead, TimerElemPtr t) */
 118     TimerElemPtr *qhead, t;
 119 {
 120     TimerElemPtr p;             /* parent pointer */
 121     TimerElemPtr n;             /* current */
 122
 123     if ( !t->onQ) {
 124         /*
 125                 * someone else beat us to the punch and took this
 126                 * element off of the queue, just return in this case
 127                 */
 128                 return;
 129     }
 130     p = (TimerElemPtr)qhead;
 131
 132     while ((n = p->link))       /* Get next item in queue */
 133     {
 134         if (n == t)             /* Is it us? */
 135         {
 136             if ((p->link = n->link)) /* Link our parent to our child */
 137             {
 138                 n->link->timer += t->timer; /* and update child's timer */
 139             }
 140             n->onQ = 0;         /* Not on linked list anymore */
 141             break;
 142         }
 143         p = n;
 144     }                           /* while */
 145
 146 }
 147
 148
 149 /*
 150  * TimerQueueTick
 151  *
 152  * INPUTS:
 153  *      qhead           Address of ptr to first item in list
 154  *
 155  * OUTPUTS:
 156  *      void
 157  */
 158 void TimerQueueTick(qhead)      /* (TimerElemPtr *qhead) */
 159     TimerElemPtr *qhead;
 160 {
 161     TimerElemPtr p;             /* parent pointer */
 162     TimerElemPtr n;             /* current */
 163
 164     p = (TimerElemPtr)qhead;
 165     if (p->link) {              /* Is anything on queue? */
 166         p->link->timer--;       /* Yes, decrement by a tick */
 167         while ((n = p->link) &&
 168                (n->timer == 0)) /* Next guy needs to be serviced */
 169         {
 170                 p->link = n->link;      /* Unlink us */
 171                 n->onQ  = 0;
 172
 173                 DoTimerElem(n);
 174
 175                 p = (TimerElemPtr)qhead;
 176         }                               /* while */
 177     }
 178 }