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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:54:16 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:54:16 +0000 |
commit | 485f6ecd453d8a2fd8b9b9fadea03159d8b50797 (patch) | |
tree | 32451fa3cdd9321fb2591fada9891b2cb70a9cd1 /grub-core/lib/datetime.c | |
parent | Initial commit. (diff) | |
download | grub2-485f6ecd453d8a2fd8b9b9fadea03159d8b50797.tar.xz grub2-485f6ecd453d8a2fd8b9b9fadea03159d8b50797.zip |
Adding upstream version 2.06.upstream/2.06upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'grub-core/lib/datetime.c')
-rw-r--r-- | grub-core/lib/datetime.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/grub-core/lib/datetime.c b/grub-core/lib/datetime.c new file mode 100644 index 0000000..9120128 --- /dev/null +++ b/grub-core/lib/datetime.c @@ -0,0 +1,117 @@ +/* datetime.c - Module for common datetime function. */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2008 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/datetime.h> +#include <grub/i18n.h> +#include <grub/misc.h> +#include <grub/mm.h> + +static const char *const grub_weekday_names[] = +{ + N_("Sunday"), + N_("Monday"), + N_("Tuesday"), + N_("Wednesday"), + N_("Thursday"), + N_("Friday"), + N_("Saturday"), +}; + +int +grub_get_weekday (struct grub_datetime *datetime) +{ + unsigned a, y, m; + + if (datetime->month <= 2) + a = 1; + else + a = 0; + y = datetime->year - a; + m = datetime->month + 12 * a - 2; + + return (datetime->day + y + y / 4 - y / 100 + y / 400 + (31 * m / 12)) % 7; +} + +const char * +grub_get_weekday_name (struct grub_datetime *datetime) +{ + return _ (grub_weekday_names[grub_get_weekday (datetime)]); +} + +#define SECPERMIN 60 +#define SECPERHOUR (60*SECPERMIN) +#define SECPERDAY (24*SECPERHOUR) +#define DAYSPERYEAR 365 +#define DAYSPER4YEARS (4*DAYSPERYEAR+1) + + +void +grub_unixtime2datetime (grub_int64_t nix, struct grub_datetime *datetime) +{ + int i; + grub_uint8_t months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; + /* In the period of validity of unixtime all years divisible by 4 + are bissextile*/ + /* Convenience: let's have 3 consecutive non-bissextile years + at the beginning of the counting date. So count from 1901. */ + int days_epoch; + /* Number of days since 1st Januar, 1901. */ + unsigned days; + /* Seconds into current day. */ + unsigned secs_in_day; + + /* Transform C divisions and modulos to mathematical ones */ + if (nix < 0) + /* + * The result of division here shouldn't be larger than GRUB_INT_MAX. + * So, it's safe to store the result back in an int. + */ + days_epoch = -(grub_divmod64 (((grub_int64_t) (SECPERDAY) - nix - 1), SECPERDAY, NULL)); + else + days_epoch = grub_divmod64 (nix, SECPERDAY, NULL); + + secs_in_day = nix - days_epoch * SECPERDAY; + days = days_epoch + 69 * DAYSPERYEAR + 17; + + datetime->year = 1901 + 4 * (days / DAYSPER4YEARS); + days %= DAYSPER4YEARS; + /* On 31st December of bissextile years 365 days from the beginning + of the year elapsed but year isn't finished yet */ + if (days / DAYSPERYEAR == 4) + { + datetime->year += 3; + days -= 3*DAYSPERYEAR; + } + else + { + datetime->year += days / DAYSPERYEAR; + days %= DAYSPERYEAR; + } + for (i = 0; i < 12 + && days >= (i==1 && datetime->year % 4 == 0 + ? 29 : months[i]); i++) + days -= (i==1 && datetime->year % 4 == 0 + ? 29 : months[i]); + datetime->month = i + 1; + datetime->day = 1 + days; + datetime->hour = (secs_in_day / SECPERHOUR); + secs_in_day %= SECPERHOUR; + datetime->minute = secs_in_day / SECPERMIN; + datetime->second = secs_in_day % SECPERMIN; +} |