timetag.c

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/*
 *  Copyright (C) 2004 Steve Harris
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 *  $Id$
 */

#include "lo_types_internal.h"
#include "lo/lo.h"

#ifdef _MSC_VER
lo_timetag lo_get_tt_immediate() { lo_timetag tt = {0U,1U}; return tt; }
#else
#include <sys/time.h>
#endif
#include <time.h>

#define JAN_1970 0x83aa7e80      /* 2208988800 1970 - 1900 in seconds */

double lo_timetag_diff(lo_timetag a, lo_timetag b)
{
    return (double)a.sec - (double)b.sec +
        ((double)a.frac - (double)b.frac) * 0.00000000023283064365;
}

void lo_timetag_now(lo_timetag *t)
{
#ifdef WIN32
    /* 
        FILETIME is the time in units of 100 nsecs from 1601-Jan-01
        1601 and 1900 are 9435484800 seconds apart.
    */
    FILETIME ftime;
    double dtime;
    GetSystemTimeAsFileTime(&ftime);
    dtime = 
        ((ftime.dwHighDateTime*4294967296.e-7)-9435484800.)+
        (ftime.dwLowDateTime*1.e-7);

    t->sec = (uint32_t)dtime;
    t->frac = (uint32_t)((dtime-t->sec)*4294967296.);
#else
    struct timeval tv;

    gettimeofday(&tv, NULL);
    t->sec = tv.tv_sec + JAN_1970;
    t->frac = tv.tv_usec * 4294.967295;
#endif
}