FUNCTIONS

1. SDL_StartTicks
2. SDL_GetTicks
3. SDL_Delay
4. RunTimer
5. SDL_SYS_TimerInit
6. SDL_SYS_TimerQuit
7. SDL_SYS_StartTimer
8. SDL_SYS_StopTimer

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
   4 
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Library General Public
   7     License as published by the Free Software Foundation; either
   8     version 2 of the License, or (at your option) any later version.
   9 
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Library General Public License for more details.
  14 
  15     You should have received a copy of the GNU Library General Public
  16     License along with this library; if not, write to the Free
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 
  19     Sam Lantinga
  20     slouken@devolution.com
  21 */
  23 #ifdef SAVE_RCSID
  24 static char rcsid =
  25  "@(#) $Id: SDL_systimer.c,v 1.1.2.2 2001/02/10 07:20:05 hercules Exp $";
  26 #endif
  28 #include <stdio.h>
  29 #include <sys/time.h>
  30 #include <signal.h>
  31 #include <unistd.h>
  32 #include <string.h>
  33 #include <errno.h>
  35 #include "SDL_error.h"
  36 #include "SDL_timer.h"
  37 #include "SDL_timer_c.h"
  39 /* The first ticks value of the application */
  40 static struct timeval start;
  42 void SDL_StartTicks(void)
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  43 {
  44         /* Set first ticks value */
  45         gettimeofday(&start, NULL);
  46 }
  48 Uint32 SDL_GetTicks (void)
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  49 {
  50         struct timeval now;
  51         Uint32 ticks;
  53         gettimeofday(&now, NULL);
  54         ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;
  55         return(ticks);
  56 }
  58 void SDL_Delay (Uint32 ms)
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  59 {
  60         int was_error;
  61 #ifndef linux   /* Non-Linux implementations need to calculate time left */
  62         Uint32 then, now, elapsed;
  63 #endif
  64         struct timeval tv;
  66         /* Set the timeout interval - Linux only needs to do this once */
  67 #ifdef linux
  68         tv.tv_sec = ms/1000;
  69         tv.tv_usec = (ms%1000)*1000;
  70 #else
  71         then = SDL_GetTicks();
  72 #endif
  73         do {
  74                 errno = 0;
  75 #ifndef linux
  76                 /* Calculate the time interval left (in case of interrupt) */
  77                 now = SDL_GetTicks();
  78                 elapsed = (now-then);
  79                 then = now;
  80                 if ( elapsed >= ms ) {
  81                         break;
  82                 }
  83                 ms -= elapsed;
  84                 tv.tv_sec = ms/1000;
  85                 tv.tv_usec = (ms%1000)*1000;
  86 #endif
  87                 was_error = select(0, NULL, NULL, NULL, &tv);
  88         } while ( was_error && (errno == EINTR) );
  89 }
  91 #include "SDL_thread.h"
  93 /* Data to handle a single periodic alarm */
  94 static int timer_alive = 0;
  95 static SDL_Thread *timer = NULL;
  97 static int RunTimer(void *unused)
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  98 {
  99         while ( timer_alive ) {
 100                 if ( SDL_timer_running ) {
SDL_ThreadedTimerCheck();
 102                 }
SDL_Delay(1);
 104         }
 105         return(0);
 106 }
 108 /* This is only called if the event thread is not running */
 109 int SDL_SYS_TimerInit(void)
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 110 {
 111 #ifdef NO_AMIGADEBUG
 112         fprintf(stderr,"Creo il thread per il timer (NOITMER)...\n");
 113 #endif
 114         timer_alive = 1;
 115         timer = SDL_CreateThread(RunTimer, NULL);
 116         if ( timer == NULL )
 117         {
 118 #ifdef NO_AMIGADEBUG
 119                 fprintf(stderr,"Creazione del thread fallita...\n");
 120 #endif
 122                 return(-1);
 123         }
 124         return(SDL_SetTimerThreaded(1));
 125 }
 127 void SDL_SYS_TimerQuit(void)
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 128 {
 129         timer_alive = 0;
 130         if ( timer ) {
SDL_WaitThread(timer, NULL);
 132                 timer = NULL;
 133         }
 134 }
 136 int SDL_SYS_StartTimer(void)
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 137 {
SDL_SetError("Internal logic error: Linux uses threaded timer");
 139         return(-1);
 140 }
 142 void SDL_SYS_StopTimer(void)
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 143 {
 144         return;
 145 }