/**************************************************************************** * libs/libc/time/lib_gmtimer.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Calendar/UTC conversion routines */ static void clock_utc2calendar(time_t utc, FAR int *year, FAR int *month, FAR int *day); #ifdef CONFIG_GREGORIAN_TIME static void clock_utc2gregorian(time_t jdn, FAR int *year, FAR int *month, FAR int *day); #ifdef CONFIG_JULIAN_TIME static void clock_utc2julian(time_t jdn, FAR int *year, FAR int *month, FAR int *day); #endif /* CONFIG_JULIAN_TIME */ #endif /* CONFIG_GREGORIAN_TIME */ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: clock_utc2calendar, clock_utc2gregorian, and clock_utc2julian * * Description: * Calendar to UTC conversion routines. These conversions * are based on algorithms from p. 604 of Seidelman, P. K. * 1992. Explanatory Supplement to the Astronomical * Almanac. University Science Books, Mill Valley. * ****************************************************************************/ #ifdef CONFIG_GREGORIAN_TIME static void clock_utc2calendar(time_t utc, FAR int *year, FAR int *month, FAR int *day) { #ifdef CONFIG_JULIAN_TIME if (utc >= GREG_DUTC) { clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day); } else { clock_utc2julian (utc + JD_OF_EPOCH, year, month, day); } #else /* CONFIG_JULIAN_TIME */ clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day); #endif /* CONFIG_JULIAN_TIME */ } static void clock_utc2gregorian(time_t jd, FAR int *year, FAR int *month, FAR int *day) { long l; long n; long i; long j; long d; long m; long y; l = jd + 68569; n = (4 * l) / 146097; l = l - (146097 * n + 3) / 4; i = (4000 * (l + 1)) / 1461001; l = l - (1461 * i) / 4 + 31; j = (80 * l) / 2447; d = l - (2447 * j) / 80; l = j / 11; m = j + 2 - 12 * l; y = 100 * (n - 49) + i + l; *year = y; *month = m; *day = d; } #ifdef CONFIG_JULIAN_TIME static void clock_utc2julian(time_t jd, FAR int *year, FAR int *month, FAR int *day) { long j; long k; long l; long n; long d; long i; long m; long y; j = jd + 1402; k = (j - 1) / 1461; l = j - 1461 * k; n = (l - 1) / 365 - l / 1461; i = l - 365 * n + 30; j = (80 * i) / 2447; d = i - (2447 * j) / 80; i = j / 11; m = j + 2 - 12 * i; y = 4 * k + n + i - 4716; *year = y; *month = m; *day = d; } #endif /* CONFIG_JULIAN_TIME */ #else/* CONFIG_GREGORIAN_TIME */ /* Only handles dates since Jan 1, 1970 */ static void clock_utc2calendar(time_t days, FAR int *year, FAR int *month, FAR 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 * DAYSPERNYEAR + 1); /* Number of 4-years periods since the epoch */ days -= value * (4 * DAYSPERNYEAR + 1); /* Remaining days */ value <<= 2; /* Years since the epoch */ /* Then we will brute force the next 0-3 years * * Is this year a leap year? (we'll need this later too) */ leapyear = clock_isleapyear(value + EPOCH_YEAR); /* Get the number of days in the year */ tmp = (leapyear ? DAYSPERLYEAR : DAYSPERNYEAR); /* Do we have that many days left to account for? */ while (days >= tmp) { /* Yes.. bump up the year and subtract the number of days in the year */ value++; days -= tmp; /* Is the next year a leap year? */ leapyear = clock_isleapyear(value + EPOCH_YEAR); /* Get the number of days in the next year */ tmp = (leapyear ? DAYSPERLYEAR : DAYSPERNYEAR); } /* At this point, 'value' has the years since 1970 and 'days' has number * of days into that year. 'leapyear' is true if the year in 'value' is * a leap year. */ *year = EPOCH_YEAR + 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 somewhere 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 */ } #endif /* CONFIG_GREGORIAN_TIME */ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: gmtime_r * * Description: * Time conversion (based on the POSIX API) * ****************************************************************************/ FAR struct tm *gmtime_r(FAR const time_t *timep, 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 = *timep; linfo("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; linfo("hour=%d min=%d sec=%d\n", hour, min, sec); /* Convert the days since the EPOCH to calendar day */ clock_utc2calendar(jdn, &year, &month, &day); linfo("jdn=%d year=%d month=%d day=%d\n", (int)jdn, year, month, day); /* Then return the struct tm contents */ result->tm_year = year - TM_YEAR_BASE; /* Relative to 1900 */ result->tm_mon = month - 1; /* zero-based */ result->tm_mday = day; /* one-based */ result->tm_hour = hour; result->tm_min = min; result->tm_sec = sec; result->tm_wday = clock_dayoftheweek(day, month, year); result->tm_yday = day - 1 + clock_daysbeforemonth(result->tm_mon, clock_isleapyear(year)); result->tm_isdst = 0; result->tm_gmtoff = 0; result->tm_zone = NULL; return result; } FAR struct tm *localtime_r(FAR const time_t *timep, FAR struct tm *result) { return gmtime_r(timep, result); }