mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Steel/c/alarm

   1 /*
   2  * alarm.c
   3  *
   4  * Calling routines at set times
   5  *
   6  * © 1994-1998 Straylight
   7  */
   8
   9 /*----- Licensing note ----------------------------------------------------*
  10  *
  11  * This file is part of Straylight's Steel library.
  12  *
  13  * Steel is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * Steel is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with Steel.  If not, write to the Free Software Foundation,
  25  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26  */
  27
  28 #include "alarm.h"
  29 #include "mem.h"
  30 #include "werr.h"
  31 #include "msgs.h"
  32 #include "os.h"
  33 #include "swiv.h"
  34 #include "swis.h"
  35
  36 typedef struct alarm__str
  37 {
  38   struct alarm__str *next;
  39   alarm_handler proc;
  40   void *handle;
  41   int time;
  42 }
  43 alarm__str;
  44
  45 static alarm__str *alarm__all;
  46
  47 /*
  48  * void alarm_init(void)
  49  *
  50  * Use
  51  *  None at all
  52  */
  53
  54 void alarm_init(void)
  55 {
  56   /* Hmmm.... this *is* an interesting function */
  57 }
  58
  59 /*
  60  * int alarm_timenow(void)
  61  *
  62  * Use
  63  *  Reports the time right now
  64  */
  65
  66 int alarm_timenow(void)
  67 {
  68   return (_swi(OS_ReadMonotonicTime,_return(0)));
  69 }
  70
  71 /*
  72  * int alarm_timedifference(int t1,int t2)
  73  *
  74  * Use
  75  *  Tells you the difference between two times.  t2 is considered to be later
  76  *  than t1.
  77  */
  78
  79 int alarm_timedifference(int t1,int t2)
  80 {
  81   /* --- Humm.... How to deal with wraparound --- *
  82    *
  83    * Answer: Ignore it and subtract -- mod 2^32 arithmetic + 2s complement
  84    * sorts it all out for you.
  85    */
  86
  87   return (t2-t1);
  88 }
  89
  90 /*
  91  * void alarm_set(int at,alarm_handler proc,void *handle)
  92  *
  93  * Use
  94  *  Sets up `proc' to be called at time `at', being passed `handle'.
  95  */
  96
  97 void alarm_set(int at,alarm_handler proc,void *handle)
  98 {
  99   alarm__str *a=mem_alloc(sizeof(alarm__str));
 100   alarm__str *p;
 101   if (!a)
 102     werr(FALSE,msgs_lookup("alarmNEM:Not enough memory for alarm"));
 103   else
 104   {
 105     /* --- Fill in the structure --- */
 106
 107     a->time=at;
 108     a->proc=proc;
 109     a->handle=handle;
 110
 111     /* --- Scan the list and put the new node in the right place --- *
 112      *
 113      * Is this the right condition for the times?
 114      */
 115
 116     p=(alarm__str *)&alarm__all;
 117     while (p->next && p->next->time<at)
 118       p=p->next;
 119     a->next=p->next;
 120     p->next=a;
 121   }
 122 }
 123
 124 /*
 125  * void alarm_remove(int at,void *handle)
 126  *
 127  * Use
 128  *  Removes an alarm identified by a time and a handle
 129  */
 130
 131 void alarm_remove(int at,void *handle)
 132 {
 133   alarm__str *p;
 134   alarm__str *q;
 135
 136   p=(alarm__str *)&alarm__all;
 137   while (p->next)
 138   {
 139     if (p->next->time==at && p->next->handle==handle)
 140     {
 141       q=p->next;
 142       p->next=q->next;
 143       mem_free(q);
 144       return;
 145     }
 146     p=p->next;
 147   }
 148 }
 149
 150 /*
 151  * void alarm_removeall(void *handle)
 152  *
 153  * Use
 154  *  Removes all alarms for the given handle
 155  */
 156
 157 void alarm_removeall(void *handle)
 158 {
 159   alarm__str *p;
 160   alarm__str *q;
 161
 162   p=(alarm__str *)&alarm__all;
 163   while (p->next)
 164   {
 165     if (p->next->handle==handle)
 166     {
 167       q=p->next;
 168       p->next=q->next;
 169       mem_free(q);
 170     }
 171     else
 172       p=p->next;
 173   }
 174 }
 175
 176 /*
 177  * BOOL alarm_anypending(void *handle)
 178  *
 179  * Use
 180  *  Returns TRUE if there are alarms for the given handle
 181  */
 182
 183 BOOL alarm_anypending(void *handle)
 184 {
 185   alarm__str *p=alarm__all;
 186
 187   while (p)
 188   {
 189     if (p->handle==handle)
 190       return (TRUE);
 191     p=p->next;
 192   }
 193   return (FALSE);
 194 }
 195
 196 /*
 197  * BOOL alarm_next(int *when)
 198  *
 199  * Use
 200  *  Informs the caller (a) if there are any alarms waiting, and (b) when
 201  *  the next one is.
 202  *
 203  * Parameters
 204  *  int *when == where to put the next time for an alarm (unchanged if no
 205  *    alarm is set)
 206  *
 207  * Returns
 208  *  TRUE if there are any alarms left
 209  */
 210
 211 BOOL alarm_next(int *when)
 212 {
 213   if (alarm__all)
 214   {
 215     *when=alarm__all->time;
 216     return (TRUE);
 217   }
 218   else
 219     return (FALSE);
 220 }
 221
 222 /*
 223  * void alarm_callnext(void)
 224  *
 225  * Use
 226  *  Calls the next alarm and removes it from the list
 227  */
 228
 229 void alarm_callnext(void)
 230 {
 231   alarm__str a;
 232
 233   if (!alarm__all)
 234     return;
 235
 236   a=*alarm__all;
 237   mem_free(alarm__all);
 238   alarm__all=a.next;
 239   a.proc(a.time,a.handle);
 240 }