apps/lib/stdlibc/time.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU Lesser General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program 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
  13     GNU Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <sys/types.h>
  20 #include <time.h>
  21 #include <cmos.h>
  22 #include <syscall.h>
  23 #include <stdio.h>
  24
  25 static time_t start_time = 0;
  26 static clock_t start_ticks;
  27
  28 static int is_leapyear(unsigned int year) {
  29   if (year%400==0) return 1;
  30   else if (year%100==0) return 0;
  31   else if (year%4==0) return 1;
  32   else return 0;
  33 }
  34
  35 static void getyday(struct tm *tm) {
  36   unsigned int mdays[12] = {
  37     31,
  38     31+28,
  39     31+28+31,
  40     31+28+31+30,
  41     31+28+31+30+31,
  42     31+28+31+30+31+30,
  43     31+28+31+30+31+30+31,
  44     31+28+31+30+31+30+31+31,
  45     31+28+31+30+31+30+31+31+30,
  46     31+28+31+30+31+30+31+31+30+31,
  47     31+28+31+30+31+30+31+31+30+31+30,
  48     31+28+31+30+31+30+31+31+30+31+30+31
  49   };
  50
  51   tm->tm_yday = (tm->tm_mon>0?mdays[tm->tm_mon-1]:0)+tm->tm_mday;
  52   if (is_leapyear(tm->tm_year+1900)) tm->tm_yday++;
  53 }
  54
  55 static void getwday(struct tm *tm) {
  56   unsigned int doomsdays[] = {1,6,4,2};
  57   unsigned int year = tm->tm_year+1900;
  58   unsigned int dday_idx = (year/100)%4;
  59   unsigned int step1 = (year%100)/12;
  60   unsigned int step2 = (year%100)%12;
  61   unsigned int step3 = step2/4;
  62   unsigned int dday_year = (doomsdays[dday_idx]+((step1+step2+step3)%7))%7;
  63   unsigned int january0 = dday_year+(7-((59+is_leapyear(year)?1:0)%7));
  64   tm->tm_wday = ((january0+(tm->tm_yday%7))%7)-1;
  65 }
  66
  67 char *asctime(const struct tm *timeptr) {
  68   char *wday_name[] = {"Sun","Mon","Tue","Wed","Thu", "Fri","Sat"};
  69   char *mon_name[] = {"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};
  70   static char result[26];
  71   sprintf(result,"%s %s %u %02u:%02u:%02u %u\n",wday_name[timeptr->tm_wday],mon_name[timeptr->tm_mon],timeptr->tm_mday,timeptr->tm_hour,timeptr->tm_min, timeptr->tm_sec,1900+timeptr->tm_year);
  72   return result;
  73 }
  74
  75 time_t time(time_t *tloc) {
  76   if (start_time==0) {
  77     struct tm tm = {
  78       .tm_sec = cmos_getsecond(),
  79       .tm_min = cmos_getminute(),
  80       .tm_hour = cmos_gethour(),
  81       .tm_mday = cmos_getday(),
  82       .tm_mon = cmos_getmonth()-1,
  83       .tm_year = cmos_getyear()-1900
  84     };
  85     getyday(&tm);
  86     getwday(&tm);
  87
  88     start_time = mktime(&tm);
  89     start_ticks = clock();
  90   }
  91
  92   time_t time = start_time+(clock()-start_ticks)/CLOCKS_PER_SEC;
  93
  94   if (tloc!=NULL) *tloc = time;
  95   return time;
  96 }
  97
  98 time_t mktime(struct tm *tm) {
  99   return tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600 + tm->tm_yday*86400 +
 100          (tm->tm_year-70)*31536000 + ((tm->tm_year-69)/4)*86400 -
 101          ((tm->tm_year-1)/100)*86400 + ((tm->tm_year+299)/400)*86400;
 102 }
 103
 104 static clock_t start_clock = -1;
 105 clock_t clock() {
 106   if (start_clock==-1) start_clock = syscall_call(SYSCALL_TIME_GETTICKS,0);
 107   return syscall_call(SYSCALL_TIME_GETTICKS,0)-start_clock;
 108 }