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/*
* Copyright (c) 1995 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
static const char rcsid[] =
"@(#) $Header: /cs/research/mice/starship/src/local/CVS_repository/vic/media-timer.cc,v 1.1.1.1 1998/02/18 18:03:36 ucacsva Exp $ (LBL)";
#include "config.h"
#include <math.h>
#include "sys-time.h"
#include "media-timer.h"
MediaTimer* MediaTimer::instance_;
MediaTimer::MediaTimer()
{
instance_ = this;
offset_ = random();
}
MediaTimer::~MediaTimer()
{
instance_ = 0;
}
/*
* Default media timestamp -- convert unix system clock
* into a 90Khz timestamp. Grabbers override this virtual
* method if they can provide their own time base.
*
* XXX
* We save the corresponding unix time stamp to handle the
* unix_ts() call the transmitter will make to get the correspondence
* between the media timestamp & unix time.
*/
u_int32_t MediaTimer::media_ts()
{
timeval tv;
::gettimeofday(&tv, 0);
u_int32_t u = tv.tv_usec;
u = (u << 3) + u; /* x 9 */
/* sec * 90Khz + (usec * 90Khz) / 1e6 */
u = tv.tv_sec * 90000 + (u / 100);
return (u + offset_);
}
/*
* compute media time corresponding to the current unix time.
* in this generic routine, this is the same as media_ts() but,
* if a grabber has hardware or kernel timestamping, this routine
* must compute the correspondence between the hardware timestamp
* and the unix clock and appropriately offset the timestamp to
* correspond to the current clock. (This information if vital
* for cross-media synchronization.)
*/
u_int32_t MediaTimer::ref_ts()
{
return (media_ts());
}
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