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Diffstat (limited to 'src/third_party/timelib-2018.03/dow.c')
| -rw-r--r-- | src/third_party/timelib-2018.03/dow.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/third_party/timelib-2018.03/dow.c b/src/third_party/timelib-2018.03/dow.c new file mode 100644 index 00000000000..52f43b1a89d --- /dev/null +++ b/src/third_party/timelib-2018.03/dow.c @@ -0,0 +1,216 @@ +/* + * The MIT License (MIT) + * + * Copyright (c) 2015-2019 Derick Rethans + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "timelib.h" +#include "timelib_private.h" + +static int m_table_common[13] = { -1, 0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */ +static int m_table_leap[13] = { -1, 6, 2, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */ + +static timelib_sll positive_mod(timelib_sll x, timelib_sll y) +{ + timelib_sll tmp; + + tmp = x % y; + if (tmp < 0) { + tmp += y; + } + + return tmp; +} + +static timelib_sll century_value(timelib_sll j) +{ + return 6 - positive_mod(j, 4) * 2; +} + +static timelib_sll timelib_day_of_week_ex(timelib_sll y, timelib_sll m, timelib_sll d, int iso) +{ + timelib_sll c1, y1, m1, dow; + + /* Only valid for Gregorian calendar, commented out as we don't handle + * Julian calendar. We just return the 'wrong' day of week to be + * consistent. */ + c1 = century_value(y / 100); + y1 = positive_mod(y, 100); + m1 = timelib_is_leap(y) ? m_table_leap[m] : m_table_common[m]; + dow = positive_mod((c1 + y1 + m1 + (y1 / 4) + d), 7); + if (iso) { + if (dow == 0) { + dow = 7; + } + } + return dow; +} + +timelib_sll timelib_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d) +{ + return timelib_day_of_week_ex(y, m, d, 0); +} + +timelib_sll timelib_iso_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d) +{ + return timelib_day_of_week_ex(y, m, d, 1); +} + + /* jan feb mar apr may jun jul aug sep oct nov dec */ +static int d_table_common[13] = { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; +static int d_table_leap[13] = { 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }; +static int ml_table_common[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; +static int ml_table_leap[13] = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; + +timelib_sll timelib_day_of_year(timelib_sll y, timelib_sll m, timelib_sll d) +{ + return (timelib_is_leap(y) ? d_table_leap[m] : d_table_common[m]) + d - 1; +} + +timelib_sll timelib_days_in_month(timelib_sll y, timelib_sll m) +{ + return timelib_is_leap(y) ? ml_table_leap[m] : ml_table_common[m]; +} + +void timelib_isoweek_from_date(timelib_sll y, timelib_sll m, timelib_sll d, timelib_sll *iw, timelib_sll *iy) +{ + int y_leap, prev_y_leap, doy, jan1weekday, weekday; + + y_leap = timelib_is_leap(y); + prev_y_leap = timelib_is_leap(y-1); + doy = timelib_day_of_year(y, m, d) + 1; + if (y_leap && m > 2) { + doy++; + } + jan1weekday = timelib_day_of_week(y, 1, 1); + weekday = timelib_day_of_week(y, m, d); + if (weekday == 0) weekday = 7; + if (jan1weekday == 0) jan1weekday = 7; + /* Find if Y M D falls in YearNumber Y-1, WeekNumber 52 or 53 */ + if (doy <= (8 - jan1weekday) && jan1weekday > 4) { + *iy = y - 1; + if (jan1weekday == 5 || (jan1weekday == 6 && prev_y_leap)) { + *iw = 53; + } else { + *iw = 52; + } + } else { + *iy = y; + } + /* 8. Find if Y M D falls in YearNumber Y+1, WeekNumber 1 */ + if (*iy == y) { + int i; + + i = y_leap ? 366 : 365; + if ((i - (doy - y_leap)) < (4 - weekday)) { + *iy = y + 1; + *iw = 1; + return; + } + } + /* 9. Find if Y M D falls in YearNumber Y, WeekNumber 1 through 53 */ + if (*iy == y) { + int j; + + j = doy + (7 - weekday) + (jan1weekday - 1); + *iw = j / 7; + if (jan1weekday > 4) { + *iw -= 1; + } + } +} + +void timelib_isodate_from_date(timelib_sll y, timelib_sll m, timelib_sll d, timelib_sll *iy, timelib_sll *iw, timelib_sll *id) +{ + timelib_isoweek_from_date(y, m, d, iw, iy); + *id = timelib_day_of_week_ex(y, m, d, 1); +} + +timelib_sll timelib_daynr_from_weeknr(timelib_sll iy, timelib_sll iw, timelib_sll id) +{ + timelib_sll dow, day; + + /* Figure out the dayofweek for y-1-1 */ + dow = timelib_day_of_week(iy, 1, 1); + /* then use that to figure out the offset for day 1 of week 1 */ + day = 0 - (dow > 4 ? dow - 7 : dow); + + /* Add weeks and days */ + return day + ((iw - 1) * 7) + id; +} + +void timelib_date_from_isodate(timelib_sll iy, timelib_sll iw, timelib_sll id, timelib_sll *y, timelib_sll *m, timelib_sll *d) +{ + timelib_sll daynr = timelib_daynr_from_weeknr(iy, iw, id) + 1; + int *table; + bool is_leap_year; + + // Invariant: is_leap_year == timelib_is_leap(*y) + *y = iy; + is_leap_year = timelib_is_leap(*y); + + // Establish invariant that daynr >= 0 + while (daynr <= 0) { + *y -= 1; + daynr += (is_leap_year = timelib_is_leap(*y)) ? 366 : 365; + } + + // Establish invariant that daynr <= number of days in *yr + while (daynr > (is_leap_year ? 366 : 365)) { + daynr -= is_leap_year ? 366 : 365; + *y += 1; + is_leap_year = timelib_is_leap(*y); + } + + table = is_leap_year ? ml_table_leap : ml_table_common; + + // Establish invariant that daynr <= number of days in *m + *m = 1; + while (daynr > table[*m]) { + daynr -= table[*m]; + *m += 1; + } + + *d = daynr; +} + +int timelib_valid_time(timelib_sll h, timelib_sll i, timelib_sll s) +{ + if (h < 0 || h > 23 || i < 0 || i > 59 || s < 0 || s > 59) { + return 0; + } + return 1; +} + +int timelib_valid_date(timelib_sll y, timelib_sll m, timelib_sll d) +{ + if (m < 1 || m > 12 || d < 1 || d > timelib_days_in_month(y, m)) { + return 0; + } + return 1; +} +#if 0 +int main(void) +{ + printf("dow = %d\n", timelib_day_of_week(1978, 12, 22)); /* 5 */ + printf("dow = %d\n", timelib_day_of_week(2005, 2, 19)); /* 6 */ +} +#endif |