1 | /* |
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2 | * Copyright (C) 2004 Mike Wray <mike.wray@hp.com> |
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3 | * |
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4 | * This library is free software; you can redistribute it and/or modify |
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5 | * it under the terms of the GNU Lesser General Public License as published by |
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6 | * the Free Software Foundation; either version 2.1 of the License, or |
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7 | * (at your option) any later version. |
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8 | * |
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9 | * This library is distributed in the hope that it will be useful, |
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10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 | * GNU Lesser General Public License for more details. |
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13 | * |
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14 | * You should have received a copy of the GNU Lesser General Public License |
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15 | * along with this library; if not, write to the Free Software |
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16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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17 | */ |
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18 | #include <stdlib.h> |
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19 | #include <unistd.h> |
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20 | #include <errno.h> |
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21 | #include <sys/time.h> |
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22 | #include <time.h> |
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23 | |
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24 | #include "allocate.h" |
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25 | #include "timer.h" |
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26 | |
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27 | #define MODULE_NAME "TIMER" |
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28 | #undef DEBUG |
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29 | #define DEBUG 1 |
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30 | #include "debug.h" |
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31 | |
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32 | static Timer *timers = NULL; |
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33 | |
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34 | /** Get the time now as a double (in seconds). |
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35 | * Returns zero if could not get the time. |
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36 | * |
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37 | * @return time now |
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38 | */ |
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39 | double time_now(void){ |
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40 | struct timeval time; |
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41 | if(gettimeofday(&time, NULL)) return 0.0; |
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42 | return (double)time.tv_sec + (1.0e-6 * (double)time.tv_usec); |
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43 | } |
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44 | |
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45 | /** Set the process real-time timer to go off at a given expiry time. |
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46 | * The timer will not be set to go off in less than 10 ms |
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47 | * (even if the expiry time is sooner, or in the past). |
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48 | * |
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49 | * @param expiry time (in seconds) |
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50 | * @return 0 on success, error code otherwise |
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51 | */ |
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52 | static int itimer_set(double expiry){ |
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53 | struct itimerval val = {}; |
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54 | struct itimerval old = {}; |
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55 | double now, delay; |
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56 | int err = 0; |
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57 | |
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58 | if(expiry == 0.0){ |
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59 | val.it_value.tv_sec = 0; |
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60 | val.it_value.tv_usec = 0; |
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61 | } else { |
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62 | now = time_now(); |
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63 | delay = expiry - now; |
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64 | if(delay < 0.01) delay = 0.01; |
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65 | val.it_value.tv_sec = (long)delay; |
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66 | val.it_value.tv_usec = (long)((delay - (double)(long)delay) * 1.0e6); |
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67 | } |
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68 | err = setitimer(ITIMER_REAL, &val, &old); |
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69 | return err; |
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70 | } |
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71 | |
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72 | void Timer_free(Timer *z){ |
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73 | #ifndef USE_GC |
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74 | if(!z) return; |
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75 | deallocate(z); |
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76 | #endif |
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77 | } |
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78 | |
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79 | /** Process any expired timers. |
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80 | * Calls the functions of expired timers and removes them |
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81 | * from the timer list. |
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82 | * Reschedules the interval timer for the earliest expiring timer |
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83 | * (if any). |
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84 | * |
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85 | * Should not be called from within the SIGALRM handler - set |
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86 | * a flag there and call it later. |
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87 | * |
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88 | * @return 0 on success, error code otherwise. |
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89 | */ |
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90 | int process_timers(void){ |
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91 | double now = time_now(); |
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92 | Timer *curr, *next; |
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93 | for(curr = timers; curr; curr = next){ |
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94 | next = curr->next; |
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95 | if(curr->expiry > now) break; |
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96 | if(curr->fn) curr->fn(curr->data); |
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97 | } |
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98 | timers = curr; |
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99 | itimer_set((curr ? curr->expiry : 0)); |
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100 | return 0; |
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101 | } |
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102 | |
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103 | void Timer_add(Timer *timer){ |
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104 | // Insert timer in list ordered by (increasing) expiry time. |
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105 | Timer *prev, *curr, *next; |
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106 | prev = NULL; |
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107 | for(curr = timers; curr; prev = curr, curr = next){ |
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108 | next = curr->next; |
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109 | if(timer->expiry < curr->expiry) break; |
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110 | } |
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111 | if(prev){ |
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112 | prev->next = timer; |
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113 | } else { |
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114 | timers = timer; |
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115 | } |
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116 | timer->next = curr; |
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117 | |
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118 | // Set interval timer to go off for earliest expiry time. |
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119 | itimer_set(timer->expiry); |
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120 | } |
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121 | |
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122 | Timer * Timer_set(double delay, TimerFn *fn, unsigned long data){ |
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123 | // Get 'now'. |
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124 | double now = time_now(); |
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125 | Timer *timer = NULL; |
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126 | timer = ALLOCATE(Timer); |
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127 | if(!timer) goto exit; |
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128 | // Add delay to now to get expiry time. |
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129 | timer->expiry = now + delay; |
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130 | timer->fn = fn; |
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131 | timer->data = data; |
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132 | |
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133 | Timer_add(timer); |
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134 | exit: |
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135 | return timer; |
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136 | } |
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137 | |
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138 | int Timer_cancel(Timer *timer){ |
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139 | // Remove timer from list. |
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140 | int err = -ENOENT; |
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141 | Timer *prev, *curr, *next; |
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142 | for(prev = NULL, curr = timers; curr; prev = curr, curr = next){ |
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143 | next = curr->next; |
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144 | if(curr == timer){ |
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145 | err = 0; |
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146 | if(prev){ |
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147 | prev->next = curr->next; |
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148 | } else { |
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149 | timers = curr->next; |
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150 | } |
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151 | curr->next = NULL; |
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152 | break; |
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153 | } |
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154 | } |
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155 | return err; |
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156 | } |
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157 | |
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