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#include "libcompat.h"
#ifdef __MACH__
#include <mach/clock.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <unistd.h>
#endif
#define NANOSECONDS_PER_SECOND 1000000000
int
clock_gettime (clockid_t clk_id CK_ATTRIBUTE_UNUSED, struct timespec *ts)
{
#ifdef __MACH__
/* OS X does not have clock_gettime, use mach_absolute_time */
static mach_timebase_info_data_t sTimebaseInfo;
uint64_t rawTime;
uint64_t nanos;
rawTime = mach_absolute_time ();
/*
* OS X has a function to convert abs time to nano seconds: AbsoluteToNanoseconds
* However, the function may not be available as we may not have
* access to CoreServices. Because of this, we convert the abs time
* to nano seconds manually.
*/
/*
* First grab the time base used on the system, if this is the first
* time we are being called. We can check if the value is uninitialized,
* as the denominator will be zero.
*/
if (sTimebaseInfo.denom == 0) {
(void) mach_timebase_info (&sTimebaseInfo);
}
/*
* Do the conversion. We hope that the multiplication doesn't
* overflow; the price you pay for working in fixed point.
*/
nanos = rawTime * sTimebaseInfo.numer / sTimebaseInfo.denom;
/*
* Fill in the timespec container
*/
ts->tv_sec = nanos / NANOSECONDS_PER_SECOND;
ts->tv_nsec = nanos - (ts->tv_sec * NANOSECONDS_PER_SECOND);
#else
/*
* As there is no function to fall back onto to get the current
* time, zero out the time so the caller will have a sane value.
*/
ts->tv_sec = 0;
ts->tv_nsec = 0;
#endif
return 0;
}
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