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#include "date.h"
enum month {JAN=1, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC};
enum weekday {SUN=0, MON, TUE, WED, THU, FRI, SAT};
int get_weekday_from_string(char *str) {
if (!strcmp(str, "Mon")) return MON;
else if (!strcmp(str, "Tue")) return TUE;
else if (!strcmp(str, "Wed")) return WED;
else if (!strcmp(str, "Thu")) return THU;
else if (!strcmp(str, "Fri")) return FRI;
else if (!strcmp(str, "Sat")) return SAT;
else return SUN;
}
char *weekday_to_string(int weekday) {
switch (weekday) {
case SUN: return "Sun";
case MON: return "Mon";
case TUE: return "Tue";
case WED: return "Wed";
case THU: return "Thu";
case FRI: return "Fri";
case SAT: return "Sat";
default: return "";
}
}
Date extract_date(struct tm *localtm) {
Date ret;
ret.year = 1900 + localtm->tm_year;
ret.month = 1 + localtm->tm_mon;
ret.day = localtm->tm_mday;
ret.weekday = localtm->tm_wday;
return ret;
}
Date extract_date_from_string(char *str) {
Date ret;
sscanf(str, "%d-%d-%d",
&ret.year,
&ret.month,
&ret.day);
ret.weekday = get_weekday_from_string(&str[11]);
return ret;
}
Date adjust_date(Date date) {
if (date.month == FEB && date.day > 28) {
if (date.year % 4 == 0 && date.day > 29) {
date.day -= 29; date.month++; date.weekday += 29;
} else {
date.day -= 28; date.month++; date.weekday += 29;
}
} else if (date.month == JAN || date.month == MAR || date.month == MAY || date.month == JUL ||
date.month == AUG || date.month == OCT || date.month == DEC) {
if (date.day > 31 && date.month == DEC) {
date.day -= 31; date.month = 1; date.weekday += 31;
} else if (date.day > 31) {
date.day -= 31; date.month++; date.weekday += 31;
}
} else if (date.month == APR || date.month == JUN || date.month == SEP || date.month == NOV) {
if (date.day > 30) {
date.day -= 30; date.month++; date.weekday += 30;
}
}
date.weekday = date.weekday % 7;
return date;
}
bool smaller(Date a, Date b) {
if (zero(b)) return true;
if (zero(a)) return false;
return ((a.year < b.year) ||
((a.year == b.year) && (a.month < b.month)) ||
((a.year == b.year) && (a.month == b.month) && (a.day <= b.day)));
}
bool strictly_smaller(Date a, Date b) {
if (zero(b)) return true;
if (zero(a)) return false;
return ((a.year < b.year) ||
((a.year == b.year) && (a.month < b.month)) ||
((a.year == b.year) && (a.month == b.month) && (a.day < b.day)));
}
bool eql(Date a, Date b) {
return (a.day == b.day) &&
(a.month == b.month) &&
(a.year == b.year);
}
bool zero(Date a) {
return ((a.year == 0) ||
(a.month == 0) ||
(a.day == 0));
}
void print_date(Date date) {
char *wd = weekday_to_string(date.weekday);
printf("%s %i/%i/%i\n",
wd,
date.month, date.day, date.year);
}
char *print_date_to_string(Date date) {
char *ret = (char *)calloc(16, 1);
char *wd = weekday_to_string(date.weekday);
sprintf(ret, "%s %i/%i/%i",
wd,
date.month, date.day, date.year);
return ret;
}
char *short_date_to_string(Date date) {
char *ret = (char *)calloc(16, 1);
sprintf(ret, "%i/%i/%i",
date.month, date.day, date.year);
return ret;
}
Date today(void) {
Date ret;
time_t tm;
struct tm localtm;
struct tm *ltm = &localtm;
time(&tm);
ltm = localtime(&tm);
ret = extract_date(ltm);
return ret;
}
Date tomorrow(Date td) {
Date tm = { td.day+1, td.month, td.year, td.weekday+1 };
return adjust_date(tm);
}
Date nextweek(Date td) {
Date nw = { td.day+7, td.month, td.year, td.weekday };
return adjust_date(nw);
}
Date nextmonth(Date td) {
Date nm = { td.day, td.month+1, td.year, td.weekday };
return adjust_date(nm);
}
Date nextmonday(Date td) {
if (td.weekday == MON) return nextweek(td);
else if (td.weekday == SUN) return adjust_date((Date){ td.day+1, td.month, td.year, MON });
else return adjust_date((Date){ td.day+(7-td.weekday)+1, td.month, td.year, MON });
}
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