FAR struct tm *gmtime_r(FAR const time_t *timer, FAR struct tm *result)
{
time_t epoch;
time_t jdn;
int year;
int month;
int day;
int hour;
int min;
int sec;
/* Get the seconds since the EPOCH */
epoch = *timer;
sdbg("timer=%d\n", (int)epoch);
/* Convert to days, hours, minutes, and seconds since the EPOCH */
jdn = epoch / SEC_PER_DAY;
epoch -= SEC_PER_DAY * jdn;
hour = epoch / SEC_PER_HOUR;
epoch -= SEC_PER_HOUR * hour;
min = epoch / SEC_PER_MIN;
epoch -= SEC_PER_MIN * min;
sec = epoch;
sdbg("hour=%d min=%d sec=%d\n",
(int)hour, (int)min, (int)sec);
/* Convert the days since the EPOCH to calendar day */
clock_utc2calendar(jdn, &year, &month, &day);
sdbg("jdn=%d year=%d month=%d day=%d\n",
(int)jdn, (int)year, (int)month, (int)day);
/* Then return the struct tm contents */
result->tm_year = (int)year - 1900; /* Relative to 1900 */
result->tm_mon = (int)month - 1; /* zero-based */
result->tm_mday = (int)day; /* one-based */
result->tm_hour = (int)hour;
result->tm_min = (int)min;
result->tm_sec = (int)sec;
#if defined(CONFIG_TIME_EXTENDED)
result->tm_wday = clock_dayoftheweek(day, month, year);
result->tm_yday = day + clock_daysbeforemonth(result->tm_mon, clock_isleapyear(year));
result->tm_isdst = 0;
#endif
return result;
}
time_t mktime(const struct tm *tp)
{
unsigned int days;
/* Years since epoch in units of days (ignoring leap years). */
days = (tp->tm_year - 70) * 365;
/* Add in the extra days for the leap years prior to the current year. */
days += (tp->tm_year - 69) >> 2;
/* Add in the days up to the beginning of this month. */
days += (time_t)clock_daysbeforemonth(tp->tm_mon, clock_isleapyear(tp->tm_year + 1900));
/* Add in the days since the beginning of this month (days are 1-based). */
days += tp->tm_mday - 1;
/* Then convert the seconds and add in hours, minutes, and seconds */
return ((days * 24 + tp->tm_hour) * 60 + tp->tm_min) * 60 + tp->tm_sec;
}
time_t clock_calendar2utc(int year, int month, int day)
{
time_t days;
/* Years since epoch in units of days (ignoring leap years). */
days = (year - EPOCH_YEAR) * 365;
/* Add in the extra days for the leap years prior to the current year. */
days += (year - EPOCH_YEAR - 1) >> 2;
/* Add in the days up to the beginning of this month. */
days += (time_t)clock_daysbeforemonth(month, clock_isleapyear(year));
/* Add in the days since the beginning of this month (days are 1-based). */
days += day - 1;
/* Then convert the seconds and add in hours, minutes, and seconds */
return days;
}
static void clock_utc2calendar(time_t days, int *year, int *month, int *day)
{
int value;
int min;
int max;
int tmp;
bool leapyear;
/* There is one leap year every four years, so we can get close with the
* following:
*/
value = days / (4*365 + 1); /* Number of 4-years periods since the epoch*/
days -= value * (4*365 + 1); /* Remaining days */
value <<= 2; /* Years since the epoch */
/* Then we will brute force the next 0-3 years */
for (;;)
{
/* Is this year a leap year (we'll need this later too) */
leapyear = clock_isleapyear(value + 1970);
/* Get the number of days in the year */
tmp = (leapyear ? 366 : 365);
/* Do we have that many days? */
if (days >= tmp)
{
/* Yes.. bump up the year */
value++;
days -= tmp;
}
else
{
/* Nope... then go handle months */
break;
}
}
/* At this point, value has the year and days has number days into this year */
*year = 1970 + value;
/* Handle the month (zero based) */
min = 0;
max = 11;
do
{
/* Get the midpoint */
value = (min + max) >> 1;
/* Get the number of days that occurred before the beginning of the month
* following the midpoint.
*/
tmp = clock_daysbeforemonth(value + 1, leapyear);
/* Does the number of days before this month that equal or exceed the
* number of days we have remaining?
*/
if (tmp > days)
{
/* Yes.. then the month we want is somewhere from 'min' and to the
* midpoint, 'value'. Could it be the midpoint?
*/
tmp = clock_daysbeforemonth(value, leapyear);
if (tmp > days)
{
/* No... The one we want is somewhere between min and value-1 */
max = value - 1;
}
else
{
/* Yes.. 'value' contains the month that we want */
break;
}
}
else
{
/* No... The one we want is somwhere between value+1 and max */
min = value + 1;
}
/* If we break out of the loop because min == max, then we want value
* to be equal to min == max.
*/
value = min;
}
while (min < max);
/* The selected month number is in value. Subtract the number of days in the
* selected month
*/
days -= clock_daysbeforemonth(value, leapyear);
/* At this point, value has the month into this year (zero based) and days has
* number of days into this month (zero based)
*/
*month = value + 1; /* 1-based */
*day = days + 1; /* 1-based */
}
size_t strftime(FAR char *s, size_t max, FAR const char *format,
FAR const struct tm *tm)
{
FAR const char *str;
FAR char *dest = s;
int chleft = max;
int value;
int len;
while (*format && chleft > 0)
{
/* Just copy regular characters */
if (*format != '%')
{
*dest++ = *format++;
chleft--;
continue;
}
/* Handle the format character */
format++;
len = 0;
switch (*format++)
{
/* %a: A three-letter abbreviation for the day of the week. */
/* %A: The full name for the day of the week. */
case 'a':
case 'A':
{
len = snprintf(dest, chleft, "Day"); /* Not supported */
}
break;
/* %h: Equivalent to %b */
case 'h':
/* %b: The abbreviated month name according to the current locale. */
case 'b':
{
if (tm->tm_mon < 12)
{
str = g_abbrevmonthname[tm->tm_mon];
len = snprintf(dest, chleft, "%s", str);
}
}
break;
/* %B: The full month name according to the current locale. */
case 'B':
{
if (tm->tm_mon < 12)
{
str = g_monthname[tm->tm_mon];
len = snprintf(dest, chleft, "%s", str);
}
}
break;
/* %y: The year as a decimal number without a century (range 00 to 99). */
case 'y':
{
len = snprintf(dest, chleft, "%02d", tm->tm_year % 100);
}
break;
/* %C: The century number (year/100) as a 2-digit integer. */
case 'C':
{
len = snprintf(dest, chleft, "%02d", tm->tm_year / 100);
}
break;
/* %d: The day of the month as a decimal number (range 01 to 31). */
case 'd':
{
len = snprintf(dest, chleft, "%02d", tm->tm_mday);
}
break;
/* %e: Like %d, the day of the month as a decimal number, but a leading
* zero is replaced by a space.
*/
case 'e':
{
len = snprintf(dest, chleft, "%2d", tm->tm_mday);
}
break;
/* %H: The hour as a decimal number using a 24-hour clock (range 00 to 23). */
case 'H':
{
len = snprintf(dest, chleft, "%02d", tm->tm_hour);
}
break;
/* %I: The hour as a decimal number using a 12-hour clock (range 01 to 12). */
case 'I':
{
len = snprintf(dest, chleft, "%02d", tm->tm_hour % 12);
}
break;
/* %j: The day of the year as a decimal number (range 001 to 366). */
case 'j':
{
if (tm->tm_mon < 12)
{
value = clock_daysbeforemonth(tm->tm_mon, clock_isleapyear(tm->tm_year)) + tm->tm_mday;
len = snprintf(dest, chleft, "%03d", value);
}
}
break;
/* %k: The hour (24-hour clock) as a decimal number (range 0 to 23);
* single digits are preceded by a blank.
*/
case 'k':
{
len = snprintf(dest, chleft, "%2d", tm->tm_hour);
}
break;
/* %l: The hour (12-hour clock) as a decimal number (range 1 to 12);
* single digits are preceded by a blank.
*/
case 'l':
{
len = snprintf(dest, chleft, "%2d", tm->tm_hour % 12);
}
break;
/* %m: The month as a decimal number (range 01 to 12). */
case 'm':
{
len = snprintf(dest, chleft, "%02d", tm->tm_mon + 1);
}
break;
/* %M: The minute as a decimal number (range 00 to 59). */
case 'M':
{
len = snprintf(dest, chleft, "%02d", tm->tm_min);
}
break;
/* %n: A newline character. */
case 'n':
{
*dest = '\n';
len = 1;
}
break;
/* %p: Either "AM" or "PM" according to the given time value. */
case 'p':
{
if (tm->tm_hour >= 12)
{
str = "PM";
}
else
{
str = "AM";
}
len = snprintf(dest, chleft, "%s", str);
}
break;
/* %P: Like %p but in lowercase: "am" or "pm" */
case 'P':
{
if (tm->tm_hour >= 12)
{
str = "pm";
}
else
{
str = "am";
}
len = snprintf(dest, chleft, "%s", str);
}
break;
/* %s: The number of seconds since the Epoch, that is, since 1970-01-01
* 00:00:00 UTC. Hmmm... mktime argume is not 'const'.
*/
case 's':
{
len = snprintf(dest, chleft, "%d", mktime((FAR struct tm *)tm));
}
break;
/* %S: The second as a decimal number (range 00 to 60). (The range is
* up to 60 to allow for occasional leap seconds.)
*/
case 'S':
{
len = snprintf(dest, chleft, "%02d", tm->tm_sec);
}
break;
/* %t: A tab character. */
case 't':
{
*dest = '\t';
len = 1;
}
break;
/* %Y: The year as a decimal number including the century. */
case 'Y':
{
len = snprintf(dest, chleft, "%04d", tm->tm_year + 1900);
}
break;
/* %%: A literal '%' character. */
case '%':
{
*dest = '%';
len = 1;
}
break;
}
/* Update counts and pointers */
dest += len;
chleft -= len;
}
/* We get here because either we have reached the end of the format string
* or because there is no more space in the user-provided buffer and the
* resulting string has been truncated.
*
* Is there space remaining in the user-provided buffer for the NUL
* terminator?
*/
if (chleft > 0)
{
/* Yes, append terminating NUL byte */
*dest = '\0';
/* And return the number of bytes in the resulting string (excluding
* the NUL terminator).
*/
return max - chleft;
}
/* The string was truncated and/or not properly terminated. Return
* zero.
*/
return 0;
}
