source/lib/timegm.c

   1 /*
   2  * Copyright (c) 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35   adapted for Samba4 by Andrew Tridgell
  36 */
  37
  38 #include "includes.h"
  39
  40 #ifndef HAVE_TIMEGM
  41
  42 static int is_leap(unsigned y)
  43 {
  44         y += 1900;
  45         return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
  46 }
  47
  48 time_t timegm(struct tm *tm)
  49 {
  50         static const unsigned ndays[2][12] ={
  51                 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
  52                 {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
  53         time_t res = 0;
  54         unsigned i;
  55
  56         if (tm->tm_mon > 12 ||
  57             tm->tm_mon < 0 ||
  58             tm->tm_mday > 31 ||
  59             tm->tm_min > 60 ||
  60             tm->tm_sec > 60 ||
  61             tm->tm_hour > 24) {
  62                 /* invalid tm structure */
  63                 return 0;
  64         }
  65
  66         for (i = 70; i < tm->tm_year; ++i)
  67                 res += is_leap(i) ? 366 : 365;
  68
  69         for (i = 0; i < tm->tm_mon; ++i)
  70                 res += ndays[is_leap(tm->tm_year)][i];
  71         res += tm->tm_mday - 1;
  72         res *= 24;
  73         res += tm->tm_hour;
  74         res *= 60;
  75         res += tm->tm_min;
  76         res *= 60;
  77         res += tm->tm_sec;
  78         return res;
  79 }
  80
  81 #endif /* HAVE_TIMEGM */