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
42 timeptr; // hush the compiler
47 // return the calendar time, seconds since the Epoch (Jan 1 1970 00:00:00)
48 time_t time(time_t *timeptr) {
61 static _CODE char monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31};
63 static _CODE char *month[]={"Jan","Feb","Mar","Apr","May","Jun",
64 "Jul","Aug","Sep","Oct","Nov","Dec"};
66 static _CODE char *day[]={"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
68 static char ascTimeBuffer[32];
70 // validate the tm structure
71 static void CheckTime(struct tm *timeptr) {
72 // we could do some normalization here, e.g.
73 // change 40 october to 9 november
74 if (timeptr->tm_sec<0) timeptr->tm_sec=0;
75 else if (timeptr->tm_sec>59) timeptr->tm_sec=59;
76 if (timeptr->tm_min<0) timeptr->tm_min=0;
77 else if (timeptr->tm_min>59) timeptr->tm_min=59;
78 if (timeptr->tm_hour<0) timeptr->tm_hour=0;
79 else if (timeptr->tm_hour>23) timeptr->tm_hour=23;
80 if (timeptr->tm_wday<0) timeptr->tm_wday=0;
81 else if (timeptr->tm_wday>6) timeptr->tm_wday=6;
82 if (timeptr->tm_mday<1) timeptr->tm_mday=1;
83 else if (timeptr->tm_mday>31) timeptr->tm_mday=31;
84 if (timeptr->tm_mon<0) timeptr->tm_mon=0;
85 else if (timeptr->tm_mon>11) timeptr->tm_mon=11;
86 if (timeptr->tm_year<0) timeptr->tm_year=0;
89 // format the time into "Sat Feb 17 17:45:23 2001\n"
90 char *asctime(struct tm *timeptr) {
92 sprintf (ascTimeBuffer, "%s %s %2d %02d:%02d:%02d %04d\n",
93 day[timeptr->tm_wday], month[timeptr->tm_mon], timeptr->tm_mday,
94 timeptr->tm_hour, timeptr->tm_min, timeptr->tm_sec,
95 timeptr->tm_year+1900);
99 char *ctime(time_t *timep) {
100 return asctime(localtime(timep));
103 static struct tm lastTime;
105 /* convert calendar time (seconds since 1970) to broken-time
106 This only works for dates between 01-01-1970 00:00:00 and
109 A leap year is ((((year%4)==0) && ((year%100)!=0)) || ((year%400)==0))
110 but since we have no fancy years between 1970 and 2038 we can do:
113 #define LEAP_YEAR(year) ((year%4)==0)
115 // forget about timezones for now
116 struct tm *localtime(time_t *timep) {
117 return gmtime(timep);
120 struct tm *gmtime(time_t *timep) {
121 unsigned long epoch=*timep;
123 unsigned char month, monthLength;
126 lastTime.tm_sec=epoch%60;
127 epoch/=60; // now it is minutes
128 lastTime.tm_min=epoch%60;
129 epoch/=60; // now it is hours
130 lastTime.tm_hour=epoch%24;
131 epoch/=24; // now it is days
132 lastTime.tm_wday=(epoch+4)%7;
136 while((days += (LEAP_YEAR(year) ? 366 : 365)) <= epoch) {
139 lastTime.tm_year=year-1900;
141 days -= LEAP_YEAR(year) ? 366 : 365;
142 epoch -= days; // now it is days in this year, starting at 0
143 lastTime.tm_yday=epoch;
148 for (month=0; month<12; month++) {
149 if (month==1) { // februari
150 if (LEAP_YEAR(year)) {
156 monthLength = monthDays[month];
159 if (epoch>=monthLength) {
165 lastTime.tm_mon=month;
166 lastTime.tm_mday=epoch+1;
173 // convert broken time to calendar time (seconds since 1970)
174 time_t mktime(struct tm *timeptr) {
175 int year=timeptr->tm_year+1900, month=timeptr->tm_mon, i;
180 // seconds from 1970 till 1 jan 00:00:00 this year
181 seconds= FIXDS390BUG (year-1970)*60*60*24*365;
183 // add extra days for leap years
184 for (i=1970; i<year; i++) {
186 seconds+= FIXDS390BUG 60*60*24;
190 // add days for this year
191 for (i=0; i<month; i++) {
192 if (i==1 && LEAP_YEAR(year)) {
193 seconds+= FIXDS390BUG 60*60*24*29;
195 seconds+= FIXDS390BUG 60*60*24*monthDays[i];
199 seconds+= FIXDS390BUG (timeptr->tm_mday-1)*60*60*24;
200 seconds+= FIXDS390BUG timeptr->tm_hour*60*60;
201 seconds+= FIXDS390BUG timeptr->tm_min*60;
202 seconds+= FIXDS390BUG timeptr->tm_sec;