pulseaudio/src/pulse/timeval.c

/* $Id$ */

/***
  This file is part of PulseAudio.
 
  PulseAudio 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.
 
  PulseAudio 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.
 
  You should have received a copy of the GNU Lesser General Public
  License along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <assert.h>
#include <stddef.h>
#include <sys/time.h>

#ifdef HAVE_WINDOWS_H
#include <windows.h>
#endif

#include "../pulsecore/winsock.h"

#include "timeval.h"

struct timeval *pa_gettimeofday(struct timeval *tv) {
#ifdef HAVE_GETTIMEOFDAY
    assert(tv);
    
    return gettimeofday(tv, NULL) < 0 ? NULL : tv;
#elif defined(OS_IS_WIN32)
    /*
     * Copied from implementation by Steven Edwards (LGPL).
     * Found on wine mailing list.
     */

#if defined(_MSC_VER) || defined(__BORLANDC__)
#define EPOCHFILETIME (116444736000000000i64)
#else
#define EPOCHFILETIME (116444736000000000LL)
#endif

    FILETIME        ft;
    LARGE_INTEGER   li;
    __int64         t;

    assert(tv);

    GetSystemTimeAsFileTime(&ft);
    li.LowPart  = ft.dwLowDateTime;
    li.HighPart = ft.dwHighDateTime;
    t  = li.QuadPart;       /* In 100-nanosecond intervals */
    t -= EPOCHFILETIME;     /* Offset to the Epoch time */
    t /= 10;                /* In microseconds */
    tv->tv_sec  = (long)(t / 1000000);
    tv->tv_usec = (long)(t % 1000000);

    return tv;
#else
#error "Platform lacks gettimeofday() or equivalent function."
#endif
}

pa_usec_t pa_timeval_diff(const struct timeval *a, const struct timeval *b) {
    pa_usec_t r;
    assert(a && b);

    /* Check which whan is the earlier time and swap the two arguments if reuqired. */
    if (pa_timeval_cmp(a, b) < 0) {
        const struct timeval *c;
        c = a;
        a = b;
        b = c;
    }

    /* Calculate the second difference*/
    r = ((pa_usec_t) a->tv_sec - b->tv_sec)* 1000000;

    /* Calculate the microsecond difference */
    if (a->tv_usec > b->tv_usec)
        r += ((pa_usec_t) a->tv_usec - b->tv_usec);
    else if (a->tv_usec < b->tv_usec)
        r -= ((pa_usec_t) b->tv_usec - a->tv_usec);

    return r;
}

int pa_timeval_cmp(const struct timeval *a, const struct timeval *b) {
    assert(a && b);

    if (a->tv_sec < b->tv_sec)
        return -1;

    if (a->tv_sec > b->tv_sec)
        return 1;

    if (a->tv_usec < b->tv_usec)
        return -1;

    if (a->tv_usec > b->tv_usec)
        return 1;

    return 0;
}

pa_usec_t pa_timeval_age(const struct timeval *tv) {
    struct timeval now;
    assert(tv);
    
    return pa_timeval_diff(pa_gettimeofday(&now), tv);
}

struct timeval* pa_timeval_add(struct timeval *tv, pa_usec_t v) {
    unsigned long secs;
    assert(tv);
    
    secs = (v/1000000);
    tv->tv_sec += (unsigned long) secs;
    v -= secs*1000000;

    tv->tv_usec += v;

    /* Normalize */
    while (tv->tv_usec >= 1000000) {
        tv->tv_sec++;
        tv->tv_usec -= 1000000;
    }

    return tv;
}