linux-imx

// SPDX-License-Identifier: LGPL-2.0+

/*

 * Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.

 * This file is part of the GNU C Library.

 * Contributed by Paul Eggert (eggert@twinsun.com).

 *

 * The GNU C Library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public License as

 * published by the Free Software Foundation; either version 2 of the

 * License, or (at your option) any later version.

 *

 * The GNU C Library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with the GNU C Library; see the file COPYING.LIB.  If not,

 * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

​

/*

 * Converts the calendar time to broken-down time representation

 * Based on code from glibc-2.6

 *

 * 2009-7-14:

 *   Moved from glibc-2.6 to kernel by Zhaolei<zhaolei@cn.fujitsu.com>

 */

​

#include <linux/time.h>

#include <linux/module.h>

​

/*

 * Nonzero if YEAR is a leap year (every 4 years,

 * except every 100th isn't, and every 400th is).

 */

static int __isleap(long year)

{

    return (year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0);

}

​

/* do a mathdiv for long type */

static long math_div(long a, long b)

{

    return a / b - (a % b < 0);

}

​

/* How many leap years between y1 and y2, y1 must less or equal to y2 */

static long leaps_between(long y1, long y2)

{

    long leaps1 = math_div(y1 - 1, 4) - math_div(y1 - 1, 100)

        + math_div(y1 - 1, 400);

    long leaps2 = math_div(y2 - 1, 4) - math_div(y2 - 1, 100)

        + math_div(y2 - 1, 400);

    return leaps2 - leaps1;

}

​

/* How many days come before each month (0-12). */

static const unsigned short __mon_yday[2][13] = {

    /* Normal years. */

    {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},

    /* Leap years. */

    {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}

};

​

#define SECS_PER_HOUR   (60 * 60)

#define SECS_PER_DAY    (SECS_PER_HOUR * 24)

​

/**

 * time64_to_tm - converts the calendar time to local broken-down time

 *

 * @totalsecs   the number of seconds elapsed since 00:00:00 on January 1, 1970,

 *      Coordinated Universal Time (UTC).

 * @offset  offset seconds adding to totalsecs.

 * @result  pointer to struct tm variable to receive broken-down time

 */

void time64_to_tm(time64_t totalsecs, int offset, struct tm *result)

{

    long days, rem, y;

    int remainder;

    const unsigned short *ip;

​

    days = div_s64_rem(totalsecs, SECS_PER_DAY, &remainder);

    rem = remainder;

    rem += offset;

    while (rem < 0) {

        rem += SECS_PER_DAY;

        --days;

    }

    while (rem >= SECS_PER_DAY) {

        rem -= SECS_PER_DAY;