firmware/libc/mktime.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Linus Nielsen Feltzing
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22
  23 #include <time.h>
  24 #include "config.h"
  25
  26 #if CONFIG_RTC
  27 /* mktime() code taken from lynx-2.8.5 source, written
  28  by Philippe De Muyter <phdm@macqel.be> */
  29 time_t mktime(struct tm *t)
  30 {
  31     short month, year;
  32     time_t result;
  33     static int m_to_d[12] =
  34         {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
  35
  36     month = t->tm_mon;
  37     year = t->tm_year + month / 12 + 1900;
  38     month %= 12;
  39     if (month < 0)
  40     {
  41         year -= 1;
  42         month += 12;
  43     }
  44     result = (year - 1970) * 365 + (year - 1969) / 4 + m_to_d[month];
  45     result = (year - 1970) * 365 + m_to_d[month];
  46     if (month <= 1)
  47         year -= 1;
  48     result += (year - 1968) / 4;
  49     result -= (year - 1900) / 100;
  50     result += (year - 1600) / 400;
  51     result += t->tm_mday;
  52     result -= 1;
  53     result *= 24;
  54     result += t->tm_hour;
  55     result *= 60;
  56     result += t->tm_min;
  57     result *= 60;
  58     result += t->tm_sec;
  59     return(result);
  60 }
  61 #endif