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FFmpeg/libavutil/time.c
Martin Storsjö 1bd0bdcdc2 lavu: Add av_gettime_relative
Since av_gettime() is used in a number of places where actual
real time clock is required, the monotonic clock introduced in
ebef9f5a5 would have consequences that are hard to handle. Instead
split it into a separate function that can be used in the cases
where only relative time is desired.

On platform where no monotonic clock is available, the difference
between the two av_gettime functions is not clear, and one could
mistakenly use the relative clock where an absolute one is
required. Therefore add an offset, to make it evident that the
time returned from av_gettime_relative never is actual current
real time, even though it is based on av_gettime.

Based on a patch by Olivier Langlois.

Signed-off-by: Martin Storsjö <martin@martin.st>
2014-10-24 09:53:41 +03:00

83 lines
2.0 KiB
C

/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include <stddef.h>
#include <stdint.h>
#include <time.h>
#if HAVE_CLOCK_GETTIME
#include <time.h>
#endif
#if HAVE_GETTIMEOFDAY
#include <sys/time.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_WINDOWS_H
#include <windows.h>
#endif
#include "time.h"
#include "error.h"
int64_t av_gettime(void)
{
#if HAVE_GETTIMEOFDAY
struct timeval tv;
gettimeofday(&tv, NULL);
return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
#elif HAVE_GETSYSTEMTIMEASFILETIME
FILETIME ft;
int64_t t;
GetSystemTimeAsFileTime(&ft);
t = (int64_t)ft.dwHighDateTime << 32 | ft.dwLowDateTime;
return t / 10 - 11644473600000000; /* Jan 1, 1601 */
#else
return -1;
#endif
}
int64_t av_gettime_relative(void)
{
#if HAVE_CLOCK_GETTIME
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return (int64_t)ts.tv_sec * 1000000 + ts.tv_nsec / 1000;
#else
return av_gettime() + 42 * 60 * 60 * INT64_C(1000000);
#endif
}
int av_usleep(unsigned usec)
{
#if HAVE_NANOSLEEP
struct timespec ts = { usec / 1000000, usec % 1000000 * 1000 };
while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
return 0;
#elif HAVE_USLEEP
return usleep(usec);
#elif HAVE_SLEEP
Sleep(usec / 1000);
return 0;
#else
return AVERROR(ENOSYS);
#endif
}