lib/asn1/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. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by Kungliga Tekniska
  20  *      Högskolan and its contributors.
  21  *
  22  * 4. Neither the name of the Institute nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include "der_locl.h"
  40
  41 RCSID("$Id$");
  42
  43 #ifndef HAVE_TIMEGM
  44
  45 static int
  46 is_leap(unsigned y)
  47 {
  48     y += 1900;
  49     return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
  50 }
  51
  52 time_t
  53 timegm (struct tm *tm)
  54 {
  55   static const unsigned ndays[2][12] ={
  56     {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
  57     {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
  58   time_t res = 0;
  59   unsigned i;
  60
  61   for (i = 70; i < tm->tm_year; ++i)
  62     res += is_leap(i) ? 366 : 365;
  63
  64   for (i = 0; i < tm->tm_mon; ++i)
  65     res += ndays[is_leap(tm->tm_year)][i];
  66   res += tm->tm_mday - 1;
  67   res *= 24;
  68   res += tm->tm_hour;
  69   res *= 60;
  70   res += tm->tm_min;
  71   res *= 60;
  72   res += tm->tm_sec;
  73   return res;
  74 }
  75
  76 #endif /* HAVE_TIMEGM */