/* $Id: time-darwin.cpp 1 1970-01-01 00:00:00Z vboxsync $ */
/** @file
 * InnoTek Portable Runtime - Time, Darwin.
 */

/*
 * Copyright (C) 2006 InnoTek Systemberatung GmbH
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file 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,
 * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
 * distribution. VirtualBox OSE is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * If you received this file as part of a commercial VirtualBox
 * distribution, then only the terms of your commercial VirtualBox
 * license agreement apply instead of the previous paragraph.
 */


/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#define LOG_GROUP RTLOGGROUP_TIME
#define RTTIME_INCL_TIMEVAL
#include <mach/mach_time.h>
#include <mach/kern_return.h>
#include <sys/time.h>
#include <time.h>

#include <iprt/time.h>
#include "internal/time.h"


DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
{
    static struct mach_timebase_info    s_Info = { 0, 0 };
    static double                       s_rdFactor = 0.0;

    /* get the factors the first time (pray we're not racing anyone) */
    if (s_Info.denom == 0)
    {
        static bool s_fFailedToGetTimeBaseInfo = false;
        if (!s_fFailedToGetTimeBaseInfo)
        {
            struct mach_timebase_info Info;
            if (mach_timebase_info(&Info) != KERN_SUCCESS)
            {
                s_rdFactor = (double)Info.numer / (double)Info.denom;
                s_Info = Info;
            }
            else
            {
                s_Info.denom = s_Info.numer = 0;
                s_fFailedToGetTimeBaseInfo = true;
            }
        }
    }

    /* special case: absolute time is in nanoseconds */
    if (s_Info.denom == 1 && s_Info.numer == 1)
        return mach_absolute_time();

    /* general case: multiply by factor to get nanoseconds. */
    if (s_rdFactor != 0.0)
        return mach_absolute_time() * s_rdFactor;

    /* worst case: fallback to gettimeofday(). */
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return (uint64_t)tv.tv_sec  * (uint64_t)(1000 * 1000 * 1000)
         + (uint64_t)(tv.tv_usec * 1000);
}


/**
 * Gets the current nanosecond timestamp.
 *
 * This differs from RTTimeNanoTS in that it will use system APIs and not do any
 * resolution or performance optimizations.
 *
 * @returns nanosecond timestamp.
 */
RTDECL(uint64_t) RTTimeSystemNanoTS(void)
{
    return rtTimeGetSystemNanoTS();
}


/**
 * Gets the current millisecond timestamp.
 *
 * This differs from RTTimeNanoTS in that it will use system APIs and not do any
 * resolution or performance optimizations.
 *
 * @returns millisecond timestamp.
 */
RTDECL(uint64_t) RTTimeSystemMilliTS(void)
{
    return rtTimeGetSystemNanoTS();
}


/**
 * Gets the current system time.
 *
 * @returns pTime.
 * @param   pTime   Where to store the time.
 */
RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
{
    /** @todo find nanosecond API for getting time of day. */
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return RTTimeSpecSetTimeval(pTime, &tv);
}