src/timer/linux/SDL_systimer.c
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FUNCTIONS
This source file includes following functions.
- SDL_StartTicks
- SDL_GetTicks
- SDL_Delay
- HandleAlarm
- SDL_SYS_TimerInit
- SDL_SYS_TimerQuit
- SDL_SYS_StartTimer
- SDL_SYS_StopTimer
- RunTimer
- SDL_SYS_TimerInit
- SDL_SYS_TimerQuit
- SDL_SYS_StartTimer
- 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 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id: SDL_systimer.c,v 1.1.2.11 2001/03/21 17:19:56 hercules Exp $";
26 #endif
27
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>
34
35 #include "SDL_error.h"
36 #include "SDL_timer.h"
37 #include "SDL_timer_c.h"
38
39 #if defined(DISABLE_THREADS) || defined(FORK_HACK)
40 #define USE_ITIMER
41 #endif
42
43 /* The following defines should really be determined at configure time */
44
45 #ifdef linux
46 /* Linux select() changes its timeout parameter upon return to contain
47 the remaining time. Most other unixen leave it unchanged or undefined. */
48 #define SELECT_SETS_REMAINING
49 #elif defined(__bsdi__) || defined(__FreeBSD__) || defined(__sun__)
50 #define USE_NANOSLEEP
51 #endif
52
53
54 /* The first ticks value of the application */
55 static struct timeval start;
56
57 void SDL_StartTicks(void)
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58 {
59 /* Set first ticks value */
60 gettimeofday(&start, NULL);
61 }
62
63 Uint32 SDL_GetTicks (void)
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64 {
65 struct timeval now;
66 Uint32 ticks;
67
68 gettimeofday(&now, NULL);
69 ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;
70 return(ticks);
71 }
72
73 void SDL_Delay (Uint32 ms)
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74 {
75 int was_error;
76
77 #ifdef USE_NANOSLEEP
78 struct timespec elapsed, tv;
79 #else
80 struct timeval tv;
81 #ifndef SELECT_SETS_REMAINING
82 Uint32 then, now, elapsed;
83 #endif
84 #endif
85
86 /* Set the timeout interval - Linux only needs to do this once */
87 #ifdef SELECT_SETS_REMAINING
88 tv.tv_sec = ms/1000;
89 tv.tv_usec = (ms%1000)*1000;
90 #elif defined(USE_NANOSLEEP)
91 elapsed.tv_sec = ms/1000;
92 elapsed.tv_nsec = (ms%1000)*1000000;
93 #else
94 then = SDL_GetTicks();
95 #endif
96 do {
97 errno = 0;
98
99 #ifdef USE_NANOSLEEP
100 tv.tv_sec = elapsed.tv_sec;
101 tv.tv_nsec = elapsed.tv_nsec;
102 was_error = nanosleep(&tv, &elapsed);
103 #else
104 #ifndef SELECT_SETS_REMAINING
105 /* Calculate the time interval left (in case of interrupt) */
106 now = SDL_GetTicks();
107 elapsed = (now-then);
108 then = now;
109 if ( elapsed >= ms ) {
110 break;
111 }
112 ms -= elapsed;
113 tv.tv_sec = ms/1000;
114 tv.tv_usec = (ms%1000)*1000;
115 #endif
116 was_error = select(0, NULL, NULL, NULL, &tv);
117 #endif /* USE_NANOSLEEP */
118 } while ( was_error && (errno == EINTR) );
119 }
120
121 #ifdef USE_ITIMER
122
123 static void HandleAlarm(int sig)
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124 {
125 Uint32 ms;
126
127 if ( SDL_alarm_callback ) {
128 ms = (*SDL_alarm_callback)(SDL_alarm_interval);
129 if ( ms != SDL_alarm_interval ) {
130 SDL_SetTimer(ms, SDL_alarm_callback);
131 }
132 }
133 }
134
135 int SDL_SYS_TimerInit(void)
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136 {
137 struct sigaction action;
138
139 /* Set the alarm handler (Linux specific) */
140 memset(&action, 0, sizeof(action));
141 action.sa_handler = HandleAlarm;
142 action.sa_flags = SA_RESTART;
143 sigemptyset(&action.sa_mask);
144 sigaction(SIGALRM, &action, NULL);
145 return(0);
146 }
147
148 void SDL_SYS_TimerQuit(void)
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149 {
150 SDL_SetTimer(0, NULL);
151 }
152
153 int SDL_SYS_StartTimer(void)
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154 {
155 struct itimerval timer;
156
157 timer.it_value.tv_sec = (SDL_alarm_interval/1000);
158 timer.it_value.tv_usec = (SDL_alarm_interval%1000)*1000;
159 timer.it_interval.tv_sec = (SDL_alarm_interval/1000);
160 timer.it_interval.tv_usec = (SDL_alarm_interval%1000)*1000;
161 setitimer(ITIMER_REAL, &timer, NULL);
162 return(0);
163 }
164
165 void SDL_SYS_StopTimer(void)
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166 {
167 struct itimerval timer;
168
169 memset(&timer, 0, (sizeof timer));
170 setitimer(ITIMER_REAL, &timer, NULL);
171 }
172
173 #else /* USE_ITIMER */
174
175 #include "SDL_thread.h"
176
177 /* Data to handle a single periodic alarm */
178 static int timer_alive = 0;
179 static SDL_Thread *timer = NULL;
180
181 static int RunTimer(void *unused)
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182 {
183 while ( timer_alive ) {
184 if ( SDL_timer_running ) {
185 SDL_ThreadedTimerCheck();
186 }
187 SDL_Delay(1);
188 }
189 return(0);
190 }
191
192 /* This is only called if the event thread is not running */
193 int SDL_SYS_TimerInit(void)
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194 {
195 timer_alive = 1;
196 timer = SDL_CreateThread(RunTimer, NULL);
197 if ( timer == NULL )
198 return(-1);
199 return(SDL_SetTimerThreaded(1));
200 }
201
202 void SDL_SYS_TimerQuit(void)
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203 {
204 timer_alive = 0;
205 if ( timer ) {
206 SDL_WaitThread(timer, NULL);
207 timer = NULL;
208 }
209 }
210
211 int SDL_SYS_StartTimer(void)
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212 {
213 SDL_SetError("Internal logic error: Linux uses threaded timer");
214 return(-1);
215 }
216
217 void SDL_SYS_StopTimer(void)
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218 {
219 return;
220 }
221
222 #endif /* USE_ITIMER */