LibC: Implement {asctime,ctime,gmtime,localtime}_r
Old non _r prefixed functions are now just wrappers around these new functions :)
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@ -7,37 +7,11 @@
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#include <time.h>
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#include <unistd.h>
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// sample implementation from https://pubs.opengroup.org/onlinepubs/9699919799/functions/asctime.html
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char* asctime(const struct tm* timeptr)
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{
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static constexpr char wday_name[][4] {
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"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
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};
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static constexpr char mon_name[][4] {
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"Jan", "Feb", "Mar", "Apr", "May", "Jun",
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"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
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};
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static char result[128];
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sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
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wday_name[timeptr->tm_wday],
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mon_name[timeptr->tm_mon],
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timeptr->tm_mday, timeptr->tm_hour,
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timeptr->tm_min, timeptr->tm_sec,
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1900 + timeptr->tm_year);
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return result;
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}
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int clock_gettime(clockid_t clock_id, struct timespec* tp)
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{
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return syscall(SYS_CLOCK_GETTIME, clock_id, tp);
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}
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char* ctime(const time_t* clock)
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{
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return asctime(localtime(clock));
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}
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int nanosleep(const struct timespec* rqtp, struct timespec* rmtp)
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{
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return syscall(SYS_NANOSLEEP, rqtp, rmtp);
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@ -53,10 +27,45 @@ time_t time(time_t* tloc)
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return tp.tv_sec;
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}
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struct tm* gmtime(const time_t* timer)
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// sample implementation from https://pubs.opengroup.org/onlinepubs/9699919799/functions/asctime.html
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char* asctime_r(const struct tm* __restrict tm, char* __restrict buf)
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{
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static struct tm tm;
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static constexpr char wday_name[][4] {
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"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
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};
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static constexpr char mon_name[][4] {
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"Jan", "Feb", "Mar", "Apr", "May", "Jun",
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"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
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};
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sprintf(buf, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
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wday_name[tm->tm_wday],
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mon_name[tm->tm_mon],
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tm->tm_mday, tm->tm_hour,
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tm->tm_min, tm->tm_sec,
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1900 + tm->tm_year);
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return buf;
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}
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char* asctime(const struct tm* timeptr)
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{
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static char buf[26];
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return asctime_r(timeptr, buf);
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}
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char* ctime_r(const time_t* clock, char* buf)
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{
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struct tm local;
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return asctime_r(localtime_r(clock, &local), buf);
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}
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char* ctime(const time_t* clock)
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{
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static char buf[26];
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return ctime_r(clock, buf);
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}
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struct tm* gmtime_r(const time_t* timer, struct tm* __restrict result)
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{
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constexpr auto is_leap_year =
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[](time_t year) -> bool
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{
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@ -73,38 +82,50 @@ struct tm* gmtime(const time_t* timer)
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time_t time = *timer;
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tm.tm_sec = time % 60; time /= 60;
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tm.tm_min = time % 60; time /= 60;
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tm.tm_hour = time % 24; time /= 24;
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result->tm_sec = time % 60; time /= 60;
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result->tm_min = time % 60; time /= 60;
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result->tm_hour = time % 24; time /= 24;
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time_t total_days = time;
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tm.tm_wday = (total_days + 4) % 7;
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tm.tm_year = 1970;
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while (total_days >= 365U + is_leap_year(tm.tm_year))
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result->tm_wday = (total_days + 4) % 7;
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result->tm_year = 1970;
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while (total_days >= 365U + is_leap_year(result->tm_year))
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{
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total_days -= 365U + is_leap_year(tm.tm_year);
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tm.tm_year++;
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total_days -= 365U + is_leap_year(result->tm_year);
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result->tm_year++;
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}
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bool is_leap_day = is_leap_year(tm.tm_year) && total_days == month_days[2];
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bool had_leap_day = is_leap_year(tm.tm_year) && total_days > month_days[2];
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bool is_leap_day = is_leap_year(result->tm_year) && total_days == month_days[2];
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bool had_leap_day = is_leap_year(result->tm_year) && total_days > month_days[2];
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for (tm.tm_mon = 0; tm.tm_mon < 12; tm.tm_mon++)
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if (total_days < month_days[tm.tm_mon + 1] + (is_leap_day || had_leap_day))
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for (result->tm_mon = 0; result->tm_mon < 12; result->tm_mon++)
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if (total_days < month_days[result->tm_mon + 1] + (is_leap_day || had_leap_day))
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break;
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tm.tm_mday = total_days - month_days[tm.tm_mon] + !had_leap_day;
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tm.tm_yday = total_days;
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tm.tm_year -= 1900;
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tm.tm_isdst = 0;
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result->tm_mday = total_days - month_days[result->tm_mon] + !had_leap_day;
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result->tm_yday = total_days;
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result->tm_year -= 1900;
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result->tm_isdst = 0;
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return &tm;
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return result;
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}
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struct tm* gmtime(const time_t* timer)
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{
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static struct tm tm;
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return gmtime_r(timer, &tm);
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}
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struct tm* localtime_r(const time_t* timer, struct tm* result)
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{
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// FIXME: support timezones
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return gmtime_r(timer, result);
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}
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struct tm* localtime(const time_t* timer)
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{
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// FIXME: support timezones
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return gmtime(timer);
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static struct tm tm;
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return localtime_r(timer, &tm);
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}
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size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict format, const struct tm* __restrict timeptr)
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