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 // please note that the tm structure has the years since 1900,
29 // but time returns the seconds since 1970
31 /* You need some kind of real time clock for the time() function.
32 Either a rtc-chip or some kind of DCF device will do. For TINI, the
33 HAVE_RTC is defined in tinibios.h
34 If not, the conversion routines still work.
38 unsigned char RtcRead(struct tm *timeptr) {
39 // no real time hardware
40 timeptr; // hush the compiler
45 // return the calendar time, seconds since the Epoch (Jan 1 1970 00:00:00)
46 time_t time(time_t *timeptr) {
59 static _CODE char monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31};
61 _CODE char * _CODE __month[]={"Jan","Feb","Mar","Apr","May","Jun",
62 "Jul","Aug","Sep","Oct","Nov","Dec"};
64 _CODE char * _CODE __day[]={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
66 static char ascTimeBuffer[32];
68 // validate the tm structure
69 static void CheckTime(struct tm *timeptr) {
70 // we could do some normalization here, e.g.
71 // change 40 october to 9 november
72 if (timeptr->tm_sec<0) timeptr->tm_sec=0;
73 else if (timeptr->tm_sec>59) timeptr->tm_sec=59;
74 if (timeptr->tm_min<0) timeptr->tm_min=0;
75 else if (timeptr->tm_min>59) timeptr->tm_min=59;
76 if (timeptr->tm_hour<0) timeptr->tm_hour=0;
77 else if (timeptr->tm_hour>23) timeptr->tm_hour=23;
78 if (timeptr->tm_wday<0) timeptr->tm_wday=0;
79 else if (timeptr->tm_wday>6) timeptr->tm_wday=6;
80 if (timeptr->tm_mday<1) timeptr->tm_mday=1;
81 else if (timeptr->tm_mday>31) timeptr->tm_mday=31;
82 if (timeptr->tm_mon<0) timeptr->tm_mon=0;
83 else if (timeptr->tm_mon>11) timeptr->tm_mon=11;
84 if (timeptr->tm_year<0) timeptr->tm_year=0;
87 // format the time into "Sat Feb 17 17:45:23 2001\n"
88 char *asctime(struct tm *timeptr) {
90 sprintf (ascTimeBuffer, "%s %s %2d %02d:%02d:%02d %04d\n",
91 __day[timeptr->tm_wday], __month[timeptr->tm_mon], timeptr->tm_mday,
92 timeptr->tm_hour, timeptr->tm_min, timeptr->tm_sec,
93 timeptr->tm_year+1900);
97 char *ctime(time_t *timep) {
98 return asctime(localtime(timep));
101 static struct tm lastTime;
103 /* convert calendar time (seconds since 1970) to broken-time
104 This only works for dates between 01-01-1970 00:00:00 and
107 A leap year is ((((year%4)==0) && ((year%100)!=0)) || ((year%400)==0))
108 but since we have no fancy years between 1970 and 2038 we can do:
111 #define LEAP_YEAR(year) ((year%4)==0)
113 // forget about timezones for now
114 struct tm *localtime(time_t *timep) {
115 return gmtime(timep);
118 struct tm *gmtime(time_t *timep) {
119 unsigned long epoch=*timep;
121 unsigned char month, monthLength;
124 lastTime.tm_sec=epoch%60;
125 epoch/=60; // now it is minutes
126 lastTime.tm_min=epoch%60;
127 epoch/=60; // now it is hours
128 lastTime.tm_hour=epoch%24;
129 epoch/=24; // now it is days
130 lastTime.tm_wday=(epoch+4)%7;
134 while((days += (LEAP_YEAR(year) ? 366 : 365)) <= epoch) {
137 lastTime.tm_year=year-1900;
139 days -= LEAP_YEAR(year) ? 366 : 365;
140 epoch -= days; // now it is days in this year, starting at 0
141 lastTime.tm_yday=epoch;
146 for (month=0; month<12; month++) {
147 if (month==1) { // februari
148 if (LEAP_YEAR(year)) {
154 monthLength = monthDays[month];
157 if (epoch>=monthLength) {
163 lastTime.tm_mon=month;
164 lastTime.tm_mday=epoch+1;
171 // convert broken time to calendar time (seconds since 1970)
172 time_t mktime(struct tm *timeptr) {
173 int year=timeptr->tm_year+1900, month=timeptr->tm_mon, i;
178 // seconds from 1970 till 1 jan 00:00:00 this year
179 seconds= (year-1970)*60*60*24*365;
181 // add extra days for leap years
182 for (i=1970; i<year; i++) {
188 // add days for this year
189 for (i=0; i<month; i++) {
190 if (i==1 && LEAP_YEAR(year)) {
191 seconds+= 60*60*24*29;
193 seconds+= 60*60*24*monthDays[i];
197 seconds+= timeptr->tm_mday-1*60*60*24;
198 seconds+= timeptr->tm_hour*60*60;
199 seconds+= timeptr->tm_min*60;
200 seconds+= timeptr->tm_sec;