diff options
Diffstat (limited to 'shared/timeutils/timeutils.c')
| -rw-r--r-- | shared/timeutils/timeutils.c | 134 |
1 files changed, 86 insertions, 48 deletions
diff --git a/shared/timeutils/timeutils.c b/shared/timeutils/timeutils.c index 4282a0178d..0c6916e06d 100644 --- a/shared/timeutils/timeutils.c +++ b/shared/timeutils/timeutils.c @@ -29,12 +29,27 @@ #include "shared/timeutils/timeutils.h" -// LEAPOCH corresponds to 2000-03-01, which is a mod-400 year, immediately -// after Feb 29. We calculate seconds as a signed integer relative to that. +// To maintain reasonable compatibility with CPython on embedded systems, +// and avoid breaking anytime soon, timeutils functions are required to +// work properly between 1970 and 2099 on all ports. // -// Our timebase is relative to 2000-01-01. - -#define LEAPOCH ((31 + 29) * 86400) +// During that period of time, leap years occur every 4 years without +// exception, so we can keep the code short for 32 bit machines. + +// The last leap day before the required period is Feb 29, 1968. +// This is the number of days to add to get to that date. +#define PREV_LEAP_DAY ((mp_uint_t)(365 + 366 - (31 + 29))) +#define PREV_LEAP_YEAR 1968 + +// On ports where either MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND or +// MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE is enabled, we include extra +// code to support leap years outside of the 'easy' period. +// Computation is then made based on 1600 (a mod-400 year). +// This is the number of days between 1600 and 1968. +#define QC_BASE_DAY 134409 +#define QC_LEAP_YEAR 1600 +// This is the number of leap days between 1600 and 1970 +#define QC_LEAP_DAYS 89 #define DAYS_PER_400Y (365 * 400 + 97) #define DAYS_PER_100Y (365 * 100 + 24) @@ -42,8 +57,20 @@ static const uint16_t days_since_jan1[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }; +// type used internally to count small integers relative to epoch +// (using uint when possible produces smaller code on some platforms) +#if MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE +typedef mp_int_t relint_t; +#else +typedef mp_uint_t relint_t; +#endif + bool timeutils_is_leap_year(mp_uint_t year) { + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0; + #else + return year % 4 == 0; + #endif } // month is one based @@ -65,67 +92,67 @@ mp_uint_t timeutils_year_day(mp_uint_t year, mp_uint_t month, mp_uint_t date) { return yday; } -void timeutils_seconds_since_2000_to_struct_time(mp_uint_t t, timeutils_struct_time_t *tm) { - // The following algorithm was adapted from musl's __secs_to_tm and adapted - // for differences in MicroPython's timebase. - - mp_int_t seconds = t - LEAPOCH; +void timeutils_seconds_since_1970_to_struct_time(timeutils_timestamp_t seconds, timeutils_struct_time_t *tm) { + // The following algorithm was inspired from musl's __secs_to_tm + // and simplified to reduce code footprint in the simple case - mp_int_t days = seconds / 86400; + relint_t days = seconds / 86400; seconds %= 86400; + #if MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE if (seconds < 0) { seconds += 86400; days -= 1; } + #endif tm->tm_hour = seconds / 3600; tm->tm_min = seconds / 60 % 60; tm->tm_sec = seconds % 60; - mp_int_t wday = (days + 2) % 7; // Mar 1, 2000 was a Wednesday (2) + relint_t wday = (days + 3) % 7; // Jan 1, 1970 was a Thursday (3) + #if MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE if (wday < 0) { wday += 7; } + #endif tm->tm_wday = wday; - mp_int_t qc_cycles = days / DAYS_PER_400Y; + days += PREV_LEAP_DAY; + + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE + // rebase day to the oldest supported date (=> always positive) + mp_uint_t base_year = QC_LEAP_YEAR; + days += QC_BASE_DAY; + mp_uint_t qc_cycles = days / DAYS_PER_400Y; days %= DAYS_PER_400Y; - if (days < 0) { - days += DAYS_PER_400Y; - qc_cycles--; - } - mp_int_t c_cycles = days / DAYS_PER_100Y; + mp_uint_t c_cycles = days / DAYS_PER_100Y; if (c_cycles == 4) { c_cycles--; } days -= (c_cycles * DAYS_PER_100Y); - - mp_int_t q_cycles = days / DAYS_PER_4Y; + #else + mp_uint_t base_year = PREV_LEAP_YEAR; + mp_uint_t qc_cycles = 0; + mp_uint_t c_cycles = 0; + #endif + + mp_uint_t q_cycles = days / DAYS_PER_4Y; + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE if (q_cycles == 25) { q_cycles--; } + #endif days -= q_cycles * DAYS_PER_4Y; - mp_int_t years = days / 365; + relint_t years = days / 365; if (years == 4) { years--; } days -= (years * 365); - /* We will compute tm_yday at the very end - mp_int_t leap = !years && (q_cycles || !c_cycles); - - tm->tm_yday = days + 31 + 28 + leap; - if (tm->tm_yday >= 365 + leap) { - tm->tm_yday -= 365 + leap; - } - - tm->tm_yday++; // Make one based - */ - - tm->tm_year = 2000 + years + 4 * q_cycles + 100 * c_cycles + 400 * qc_cycles; + tm->tm_year = base_year + years + 4 * q_cycles + 100 * c_cycles + 400 * qc_cycles; // Note: days_in_month[0] corresponds to March - static const int8_t days_in_month[] = {31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 29}; + static const uint8_t days_in_month[] = {31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 29}; mp_int_t month; for (month = 0; days_in_month[month] <= days; month++) { @@ -144,21 +171,28 @@ void timeutils_seconds_since_2000_to_struct_time(mp_uint_t t, timeutils_struct_t } // returns the number of seconds, as an integer, since 2000-01-01 -mp_uint_t timeutils_seconds_since_2000(mp_uint_t year, mp_uint_t month, +timeutils_timestamp_t timeutils_seconds_since_1970(mp_uint_t year, mp_uint_t month, mp_uint_t date, mp_uint_t hour, mp_uint_t minute, mp_uint_t second) { - return - second - + minute * 60 - + hour * 3600 - + (timeutils_year_day(year, month, date) - 1 - + ((year - 2000 + 3) / 4) // add a day each 4 years starting with 2001 - - ((year - 2000 + 99) / 100) // subtract a day each 100 years starting with 2001 - + ((year - 2000 + 399) / 400) // add a day each 400 years starting with 2001 - ) * 86400 - + (year - 2000) * 31536000; + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE + mp_uint_t ref_year = QC_LEAP_YEAR; + #else + mp_uint_t ref_year = PREV_LEAP_YEAR; + #endif + timeutils_timestamp_t res; + res = ((relint_t)year - 1970) * 365; + res += (year - (ref_year + 1)) / 4; // add a day each 4 years + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE + res -= (year - (ref_year + 1)) / 100; // subtract a day each 100 years + res += (year - (ref_year + 1)) / 400; // add a day each 400 years + res -= QC_LEAP_DAYS; + #endif + res += timeutils_year_day(year, month, date) - 1; + res *= 86400; + res += hour * 3600 + minute * 60 + second; + return res; } -mp_uint_t timeutils_mktime_2000(mp_uint_t year, mp_int_t month, mp_int_t mday, +timeutils_timestamp_t timeutils_mktime_1970(mp_uint_t year, mp_int_t month, mp_int_t mday, mp_int_t hours, mp_int_t minutes, mp_int_t seconds) { // Normalize the tuple. This allows things like: @@ -211,12 +245,16 @@ mp_uint_t timeutils_mktime_2000(mp_uint_t year, mp_int_t month, mp_int_t mday, year++; } } - return timeutils_seconds_since_2000(year, month, mday, hours, minutes, seconds); + return timeutils_seconds_since_1970(year, month, mday, hours, minutes, seconds); } // Calculate the weekday from the date. // The result is zero based with 0 = Monday. // by Michael Keith and Tom Craver, 1990. int timeutils_calc_weekday(int y, int m, int d) { - return ((d += m < 3 ? y-- : y - 2, 23 * m / 9 + d + 4 + y / 4 - y / 100 + y / 400) + 6) % 7; + return ((d += m < 3 ? y-- : y - 2, 23 * m / 9 + d + 4 + y / 4 + #if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE + - y / 100 + y / 400 + #endif + ) + 6) % 7; } |