/* glpenv06.c (standard time) */

/***********************************************************************

*  This code is part of GLPK (GNU Linear Programming Kit).

*

*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,

*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,

*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.

*  E-mail: <mao@gnu.org>.

*

*  GLPK 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 3 of the License, or

*  (at your option) any later version.

*

*  GLPK 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 GLPK. If not, see <http://www.gnu.org/licenses/>.

***********************************************************************/

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include "glpapi.h"

/***********************************************************************

*  NAME

*

*  glp_time - determine current universal time

*

*  SYNOPSIS

*

*  glp_long glp_time(void);

*

*  RETURNS

*

*  The routine glp_time returns the current universal time (UTC), in

*  milliseconds, elapsed since 00:00:00 GMT January 1, 1970. */

static const int epoch = 2440588; /* = jday(1, 1, 1970) */

/* POSIX version ******************************************************/

#if defined(HAVE_SYS_TIME_H) && defined(HAVE_GETTIMEOFDAY)

#include <sys/time.h>

#include <time.h>

glp_long glp_time(void)

{     struct timeval tv;

      struct tm *tm;

      glp_long t;

      int j;

      gettimeofday(&tv, NULL);

      tm = gmtime(&tv.tv_sec);

      j = jday(tm->tm_mday, tm->tm_mon + 1, 1900 + tm->tm_year);

      xassert(j >= 0);

      t = xlset(j - epoch);

      t = xlmul(t, xlset(24));

      t = xladd(t, xlset(tm->tm_hour));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(tm->tm_min));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(tm->tm_sec));

      t = xlmul(t, xlset(1000));

      t = xladd(t, xlset(tv.tv_usec / 1000));

      return t;

}

/* Windows version ****************************************************/

#elif defined(__WOE__)

#include <windows.h>

glp_long glp_time(void)

{     SYSTEMTIME st;

      glp_long t;

      int j;

      GetSystemTime(&st);

      j = jday(st.wDay, st.wMonth, st.wYear);

      xassert(j >= 0);

      t = xlset(j - epoch);

      t = xlmul(t, xlset(24));

      t = xladd(t, xlset(st.wHour));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(st.wMinute));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(st.wSecond));

      t = xlmul(t, xlset(1000));

      t = xladd(t, xlset(st.wMilliseconds));

      return t;

}

/* portable ISO C version *********************************************/

#else

#include <time.h>

glp_long glp_time(void)

{     time_t timer;

      struct tm *tm;

      glp_long t;

      int j;

      timer = time(NULL);

      tm = gmtime(&timer);

      j = jday(tm->tm_mday, tm->tm_mon + 1, 1900 + tm->tm_year);

      xassert(j >= 0);

      t = xlset(j - epoch);

      t = xlmul(t, xlset(24));

      t = xladd(t, xlset(tm->tm_hour));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(tm->tm_min));

      t = xlmul(t, xlset(60));

      t = xladd(t, xlset(tm->tm_sec));

      t = xlmul(t, xlset(1000));

      return t;

}

#endif

/***********************************************************************

*  NAME

*

*  glp_difftime - compute difference between two time values

*

*  SYNOPSIS

*

*  double glp_difftime(glp_long t1, glp_long t0);

*

*  RETURNS

*

*  The routine glp_difftime returns the difference between two time

*  values t1 and t0, expressed in seconds. */

double glp_difftime(glp_long t1, glp_long t0)

{     return

         xltod(xlsub(t1, t0)) / 1000.0;

}

/**********************************************************************/

#if 0

int main(void)

{     glp_long t;

      glp_ldiv d;

      int ttt, ss, mm, hh, day, month, year;

      char s[50];

      t = glp_time();

      xprintf("t = %s\n", xltoa(t, s));

      d = xldiv(t, xlset(1000));

      ttt = d.rem.lo, t = d.quot;

      d = xldiv(t, xlset(60));

      ss = d.rem.lo, t = d.quot;

      d = xldiv(t, xlset(60));

      mm = d.rem.lo, t = d.quot;

      d = xldiv(t, xlset(24));

      hh = d.rem.lo, t = d.quot;

      xassert(jdate(t.lo + epoch, &day, &month, &year) == 0);

      xprintf("%04d-%02d-%02d %02d:%02d:%02d.%03d\n", year, month, day,

         hh, mm, ss, ttt);

      return 0;

}

#endif

/* eof */