1 /*-------------------------------------------------------------------------
2 time.c - stdlib time conversion routines
4 Written By - Johan Knol, johan.knol@iduna.nl
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding!
23 -------------------------------------------------------------------------*/
28 #define FIXDS390BUG (long)
30 // please note that the tm structure has the years since 1900,
31 // but time returns the seconds since 1970
33 /* You need some kind of real time clock for the time() function.
34 Either a rtc-chip or some kind of DCF device will do. For TINI, the
35 HAVE_RTC is defined in tinibios.h
36 If not, the conversion routines still work.
40 unsigned char RtcRead(struct tm *timeptr) {
41 // no real time hardware
46 // return the calendar time, seconds since the Epoch (Jan 1 1970 00:00:00)
47 time_t time(time_t *timeptr) {
60 static code char monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31};
62 static code char *month[]={"Jan","Feb","Mar","Apr","May","Jun",
63 "Jul","Aug","Sep","Oct","Nov","Dec"};
65 static code char *day[]={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
67 static char ascTimeBuffer[32];
69 // validate the tm structure
70 static void CheckTime(struct tm *timeptr) {
71 // we could do some normalization here, e.g.
72 // change 40 october to 9 november
73 if (timeptr->tm_sec<0) timeptr->tm_sec=0;
74 else if (timeptr->tm_sec>59) timeptr->tm_sec=59;
75 if (timeptr->tm_min<0) timeptr->tm_min=0;
76 else if (timeptr->tm_min>59) timeptr->tm_min=59;
77 if (timeptr->tm_hour<0) timeptr->tm_hour=0;
78 else if (timeptr->tm_hour>23) timeptr->tm_hour=23;
79 if (timeptr->tm_wday<0) timeptr->tm_wday=0;
80 else if (timeptr->tm_wday>6) timeptr->tm_wday=6;
81 if (timeptr->tm_mday<1) timeptr->tm_mday=1;
82 else if (timeptr->tm_mday>31) timeptr->tm_mday=31;
83 if (timeptr->tm_mon<0) timeptr->tm_mon=0;
84 else if (timeptr->tm_mon>11) timeptr->tm_mon=11;
85 if (timeptr->tm_year<0) timeptr->tm_year=0;
88 // format the time into "Sat Feb 17 17:45:23 2001\n"
89 char *asctime(struct tm *timeptr) {
91 sprintf (ascTimeBuffer, "%s %s %2d %02d:%02d:%02d %04d\n",
92 day[timeptr->tm_wday], month[timeptr->tm_mon], timeptr->tm_mday,
93 timeptr->tm_hour, timeptr->tm_min, timeptr->tm_sec,
94 timeptr->tm_year+1900);
98 char *ctime(time_t *timep) {
99 return asctime(localtime(timep));
102 static struct tm lastTime;
104 /* convert calendar time (seconds since 1970) to broken-time
105 This only works for dates between 01-01-1970 00:00:00 and
108 A leap year is ((((year%4)==0) && ((year%100)!=0)) || ((year%400)==0))
109 but since we have no fancy years between 1970 and 2038 we can do:
112 #define LEAP_YEAR(year) ((year%4)==0)
114 // forget about timezones for now
115 struct tm *localtime(time_t *timep) {
116 return gmtime(timep);
119 struct tm *gmtime(time_t *timep) {
120 unsigned long epoch=*timep;
122 unsigned char month, monthLength;
125 lastTime.tm_sec=epoch%60;
126 epoch/=60; // now it is minutes
127 lastTime.tm_min=epoch%60;
128 epoch/=60; // now it is hours
129 lastTime.tm_hour=epoch%24;
130 epoch/=24; // now it is days
131 lastTime.tm_wday=(epoch+4)%7;
135 while((days += (LEAP_YEAR(year) ? 366 : 365)) <= epoch) {
138 lastTime.tm_year=year-1900;
140 days -= LEAP_YEAR(year) ? 366 : 365;
141 epoch -= days; // now it is days in this year, starting at 0
142 lastTime.tm_yday=epoch;
147 for (month=0; month<12; month++) {
148 if (month==1) { // februari
149 if (LEAP_YEAR(year)) {
155 monthLength = monthDays[month];
158 if (epoch>=monthLength) {
164 lastTime.tm_mon=month;
165 lastTime.tm_mday=epoch+1;
172 // convert broken time to calendar time (seconds since 1970)
173 time_t mktime(struct tm *timeptr) {
174 int year=timeptr->tm_year+1900, month=timeptr->tm_mon, i;
179 // seconds from 1970 till 1 jan 00:00:00 this year
180 seconds= FIXDS390BUG (year-1970)*60*60*24*365;
182 // add extra days for leap years
183 for (i=1970; i<year; i++) {
185 seconds+= FIXDS390BUG 60*60*24;
189 // add days for this year
190 for (i=0; i<month; i++) {
191 if (i==1 && LEAP_YEAR(year)) {
192 seconds+= FIXDS390BUG 60*60*24*29;
194 seconds+= FIXDS390BUG 60*60*24*monthDays[i];
198 seconds+= FIXDS390BUG (timeptr->tm_mday-1)*60*60*24;
199 seconds+= FIXDS390BUG timeptr->tm_hour*60*60;
200 seconds+= FIXDS390BUG timeptr->tm_min*60;
201 seconds+= FIXDS390BUG timeptr->tm_sec;