/*
  dostime.c - routines for converting UNIX time to MS-DOS time.  

  Borrowed from Info-zip's unzip

  Copyright (C) 1999 Bryan Burns

  This program 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 2
  of the License, or (at your option) any later version.

  This program 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 this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

/* $Id: dostime.c,v 1.1 2000/12/09 03:08:23 apbianco Exp $

   $Log: dostime.c,v $
   Revision 1.1  2000/12/09 03:08:23  apbianco
   2000-12-08  Alexandre Petit-Bianco  <apbianco@cygnus.com>

           * fastjar: Imported.

   Revision 1.1.1.1  1999/12/06 03:09:12  toast
   initial checkin..


   Revision 1.6  1999/05/10 08:32:26  burnsbr
   added dos2unixtime

   Revision 1.5  1999/04/27 10:03:50  burnsbr
   configure support

   Revision 1.4  1999/04/26 21:55:19  burnsbr
   switched from sys/time.h to time.h for better portability

   Revision 1.3  1999/04/20 08:54:30  burnsbr
   added GPL comment

   Revision 1.2  1999/04/20 05:10:53  burnsbr
   added RCS tags


*/
#include "config.h"

#ifdef TM_IN_SYS_TIME
#include <sys/time.h>
#else
#include <time.h>
#endif

#include "dostime.h"

/*

 Copyright (C) 1990-1997 Mark Adler, Richard B. Wales, Jean-loup Gailly,
 Kai Uwe Rommel, Onno van der Linden and Igor Mandrichenko.
 Permission is granted to any individual or institution to use, copy, or
 redistribute this software so long as all of the original files are included,
 that it is not sold for profit, and that this copyright notice is retained.

*/


time_t dos2unixtime(dostime)
     unsigned long dostime;            /* DOS time to convert */
     /* Return the Unix time_t value (GMT/UTC time) for the DOS format (local)
      * time dostime, where dostime is a four byte value (date in most
      * significant word, time in least significant word), see dostime() 
      * function.
      */
{
  struct tm *t;         /* argument for mktime() */
  time_t clock = time(NULL);

  t = localtime(&clock);
  t->tm_isdst = -1;     /* let mktime() determine if DST is in effect */
  /* Convert DOS time to UNIX time_t format */
  t->tm_sec  = (((int)dostime) <<  1) & 0x3e;
  t->tm_min  = (((int)dostime) >>  5) & 0x3f;
  t->tm_hour = (((int)dostime) >> 11) & 0x1f;
  t->tm_mday = (int)(dostime >> 16) & 0x1f;
  t->tm_mon  = ((int)(dostime >> 21) & 0x0f) - 1;
  t->tm_year = ((int)(dostime >> 25) & 0x7f) + 80;

  return mktime(t);
}

unsigned long dostime(y, n, d, h, m, s)
int y;                  /* year */
int n;                  /* month */
int d;                  /* day */
int h;                  /* hour */
int m;                  /* minute */
int s;                  /* second */
/* Convert the date y/n/d and time h:m:s to a four byte DOS date and
   time (date in high two bytes, time in low two bytes allowing magnitude
   comparison). */
{
  return y < 1980 ? dostime(1980, 1, 1, 0, 0, 0) :
    (((unsigned long)y - 1980) << 25) | ((unsigned long)n << 21) | 
    ((unsigned long)d << 16) | ((unsigned long)h << 11) | 
    ((unsigned long)m << 5) | ((unsigned long)s >> 1);
}


unsigned long unix2dostime(t)
time_t *t;             /* unix time to convert */
/* Return the Unix time t in DOS format, rounded up to the next two
   second boundary. */
{
  time_t t_even;
  struct tm *s;         /* result of localtime() */

  t_even = (*t + 1) & (~1);     /* Round up to even seconds. */
  s = localtime(&t_even);       /* Use local time since MSDOS does. */
  return dostime(s->tm_year + 1900, s->tm_mon + 1, s->tm_mday,
                 s->tm_hour, s->tm_min, s->tm_sec);
}