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1 /* |
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2 SDL - Simple DirectMedia Layer |
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3 Copyright (C) 1997-2006 Sam Lantinga |
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4 |
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5 This library is free software; you can redistribute it and/or |
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6 modify it under the terms of the GNU Lesser General Public |
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7 License as published by the Free Software Foundation; either |
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8 version 2.1 of the License, or (at your option) any later version. |
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9 |
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10 This library is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 Lesser General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU Lesser General Public |
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16 License along with this library; if not, write to the Free Software |
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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18 |
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19 Sam Lantinga |
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20 slouken@libsdl.org |
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21 */ |
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22 #include "SDL_config.h" |
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23 |
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24 #include "SDL_timer.h" |
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25 #include "SDL_timer_c.h" |
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26 #include "SDL_mutex.h" |
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27 #include "SDL_systimer.h" |
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28 |
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29 /* #define DEBUG_TIMERS */ |
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30 |
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31 int SDL_timer_started = 0; |
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32 int SDL_timer_running = 0; |
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33 |
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34 /* Data to handle a single periodic alarm */ |
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35 Uint32 SDL_alarm_interval = 0; |
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36 SDL_TimerCallback SDL_alarm_callback; |
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37 |
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38 /* Data used for a thread-based timer */ |
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39 static int SDL_timer_threaded = 0; |
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40 |
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41 struct _SDL_TimerID { |
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42 Uint32 interval; |
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43 SDL_NewTimerCallback cb; |
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44 void *param; |
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45 Uint32 last_alarm; |
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46 struct _SDL_TimerID *next; |
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47 }; |
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48 |
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49 static SDL_TimerID SDL_timers = NULL; |
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50 static SDL_mutex *SDL_timer_mutex; |
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51 static volatile SDL_bool list_changed = SDL_FALSE; |
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52 |
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53 /* Set whether or not the timer should use a thread. |
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54 This should not be called while the timer subsystem is running. |
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55 */ |
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56 int SDL_SetTimerThreaded(int value) |
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57 { |
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58 int retval; |
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59 |
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60 if ( SDL_timer_started ) { |
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61 SDL_SetError("Timer already initialized"); |
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62 retval = -1; |
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63 } else { |
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64 retval = 0; |
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65 SDL_timer_threaded = value; |
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66 } |
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67 return retval; |
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68 } |
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69 |
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70 int SDL_TimerInit(void) |
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71 { |
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72 int retval; |
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73 |
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74 retval = 0; |
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75 if ( SDL_timer_started ) { |
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76 SDL_TimerQuit(); |
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77 } |
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78 if ( ! SDL_timer_threaded ) { |
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79 retval = SDL_SYS_TimerInit(); |
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80 } |
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81 if ( SDL_timer_threaded ) { |
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82 SDL_timer_mutex = SDL_CreateMutex(); |
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83 } |
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84 if ( retval == 0 ) { |
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85 SDL_timer_started = 1; |
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86 } |
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87 return(retval); |
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88 } |
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89 |
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90 void SDL_TimerQuit(void) |
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91 { |
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92 SDL_SetTimer(0, NULL); |
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93 if ( SDL_timer_threaded < 2 ) { |
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94 SDL_SYS_TimerQuit(); |
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95 } |
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96 if ( SDL_timer_threaded ) { |
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97 SDL_DestroyMutex(SDL_timer_mutex); |
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98 SDL_timer_mutex = NULL; |
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99 } |
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100 SDL_timer_started = 0; |
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101 SDL_timer_threaded = 0; |
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102 } |
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103 |
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104 void SDL_ThreadedTimerCheck(void) |
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105 { |
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106 Uint32 now, ms; |
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107 SDL_TimerID t, prev, next; |
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108 SDL_bool removed; |
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109 |
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110 SDL_mutexP(SDL_timer_mutex); |
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111 list_changed = SDL_FALSE; |
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112 now = SDL_GetTicks(); |
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113 for ( prev = NULL, t = SDL_timers; t; t = next ) { |
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114 removed = SDL_FALSE; |
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115 ms = t->interval - SDL_TIMESLICE; |
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116 next = t->next; |
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117 if ( (int)(now - t->last_alarm) > (int)ms ) { |
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118 struct _SDL_TimerID timer; |
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119 |
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120 if ( (now - t->last_alarm) < t->interval ) { |
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121 t->last_alarm += t->interval; |
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122 } else { |
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123 t->last_alarm = now; |
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124 } |
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125 #ifdef DEBUG_TIMERS |
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126 printf("Executing timer %p (thread = %d)\n", |
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127 t, SDL_ThreadID()); |
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128 #endif |
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129 timer = *t; |
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130 SDL_mutexV(SDL_timer_mutex); |
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131 ms = timer.cb(timer.interval, timer.param); |
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132 SDL_mutexP(SDL_timer_mutex); |
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133 if ( list_changed ) { |
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134 /* Abort, list of timers modified */ |
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135 /* FIXME: what if ms was changed? */ |
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136 break; |
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137 } |
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138 if ( ms != t->interval ) { |
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139 if ( ms ) { |
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140 t->interval = ROUND_RESOLUTION(ms); |
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141 } else { |
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142 /* Remove timer from the list */ |
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143 #ifdef DEBUG_TIMERS |
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144 printf("SDL: Removing timer %p\n", t); |
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145 #endif |
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146 if ( prev ) { |
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147 prev->next = next; |
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148 } else { |
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149 SDL_timers = next; |
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150 } |
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151 SDL_free(t); |
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152 --SDL_timer_running; |
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153 removed = SDL_TRUE; |
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154 } |
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155 } |
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156 } |
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157 /* Don't update prev if the timer has disappeared */ |
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158 if ( ! removed ) { |
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159 prev = t; |
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160 } |
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161 } |
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162 SDL_mutexV(SDL_timer_mutex); |
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163 } |
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164 |
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165 static SDL_TimerID SDL_AddTimerInternal(Uint32 interval, SDL_NewTimerCallback callback, void *param) |
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166 { |
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167 SDL_TimerID t; |
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168 t = (SDL_TimerID) SDL_malloc(sizeof(struct _SDL_TimerID)); |
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169 if ( t ) { |
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170 t->interval = ROUND_RESOLUTION(interval); |
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171 t->cb = callback; |
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172 t->param = param; |
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173 t->last_alarm = SDL_GetTicks(); |
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174 t->next = SDL_timers; |
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175 SDL_timers = t; |
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176 ++SDL_timer_running; |
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177 list_changed = SDL_TRUE; |
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178 } |
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179 #ifdef DEBUG_TIMERS |
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180 printf("SDL_AddTimer(%d) = %08x num_timers = %d\n", interval, (Uint32)t, SDL_timer_running); |
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181 #endif |
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182 return t; |
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183 } |
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184 |
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185 SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param) |
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186 { |
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187 SDL_TimerID t; |
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188 if ( ! SDL_timer_mutex ) { |
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189 if ( SDL_timer_started ) { |
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190 SDL_SetError("This platform doesn't support multiple timers"); |
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191 } else { |
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192 SDL_SetError("You must call SDL_Init(SDL_INIT_TIMER) first"); |
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193 } |
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194 return NULL; |
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195 } |
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196 if ( ! SDL_timer_threaded ) { |
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197 SDL_SetError("Multiple timers require threaded events!"); |
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198 return NULL; |
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199 } |
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200 SDL_mutexP(SDL_timer_mutex); |
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201 t = SDL_AddTimerInternal(interval, callback, param); |
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202 SDL_mutexV(SDL_timer_mutex); |
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203 return t; |
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204 } |
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205 |
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206 SDL_bool SDL_RemoveTimer(SDL_TimerID id) |
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207 { |
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208 SDL_TimerID t, prev = NULL; |
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209 SDL_bool removed; |
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210 |
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211 removed = SDL_FALSE; |
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212 SDL_mutexP(SDL_timer_mutex); |
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213 /* Look for id in the linked list of timers */ |
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214 for (t = SDL_timers; t; prev=t, t = t->next ) { |
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215 if ( t == id ) { |
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216 if(prev) { |
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217 prev->next = t->next; |
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218 } else { |
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219 SDL_timers = t->next; |
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220 } |
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221 SDL_free(t); |
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222 --SDL_timer_running; |
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223 removed = SDL_TRUE; |
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224 list_changed = SDL_TRUE; |
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225 break; |
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226 } |
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227 } |
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228 #ifdef DEBUG_TIMERS |
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229 printf("SDL_RemoveTimer(%08x) = %d num_timers = %d thread = %d\n", (Uint32)id, removed, SDL_timer_running, SDL_ThreadID()); |
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230 #endif |
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231 SDL_mutexV(SDL_timer_mutex); |
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232 return removed; |
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233 } |
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234 |
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235 /* Old style callback functions are wrapped through this */ |
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236 static Uint32 SDLCALL callback_wrapper(Uint32 ms, void *param) |
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237 { |
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238 SDL_TimerCallback func = (SDL_TimerCallback) param; |
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239 return (*func)(ms); |
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240 } |
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241 |
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242 int SDL_SetTimer(Uint32 ms, SDL_TimerCallback callback) |
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243 { |
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244 int retval; |
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245 |
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246 #ifdef DEBUG_TIMERS |
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247 printf("SDL_SetTimer(%d)\n", ms); |
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248 #endif |
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249 retval = 0; |
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250 |
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251 if ( SDL_timer_threaded ) { |
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252 SDL_mutexP(SDL_timer_mutex); |
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253 } |
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254 if ( SDL_timer_running ) { /* Stop any currently running timer */ |
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255 if ( SDL_timer_threaded ) { |
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256 while ( SDL_timers ) { |
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257 SDL_TimerID freeme = SDL_timers; |
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258 SDL_timers = SDL_timers->next; |
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259 SDL_free(freeme); |
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260 } |
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261 SDL_timer_running = 0; |
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262 list_changed = SDL_TRUE; |
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263 } else { |
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264 SDL_SYS_StopTimer(); |
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265 SDL_timer_running = 0; |
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266 } |
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267 } |
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268 if ( ms ) { |
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269 if ( SDL_timer_threaded ) { |
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270 if ( SDL_AddTimerInternal(ms, callback_wrapper, (void *)callback) == NULL ) { |
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271 retval = -1; |
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272 } |
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273 } else { |
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274 SDL_timer_running = 1; |
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275 SDL_alarm_interval = ms; |
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276 SDL_alarm_callback = callback; |
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277 retval = SDL_SYS_StartTimer(); |
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278 } |
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279 } |
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280 if ( SDL_timer_threaded ) { |
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281 SDL_mutexV(SDL_timer_mutex); |
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282 } |
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283 |
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284 return retval; |
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285 } |