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/**************************************************************************
*
* Copyright 2008-2010 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* @file
* OS independent time-manipulation functions.
*
* @author Jose Fonseca <jfonseca@vmware.com>
*/
#ifndef _OS_TIME_H_
#define _OS_TIME_H_
#include <stdbool.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/* must be equal to PIPE_TIMEOUT_INFINITE */
#define OS_TIMEOUT_INFINITE 0xffffffffffffffffull
/*
* Get the current time in nanoseconds from an unknown base.
*/
int64_t
os_time_get_nano(void);
/*
* Get the current time in microseconds from an unknown base.
*/
static inline int64_t
os_time_get(void)
{
return os_time_get_nano() / 1000;
}
/*
* Sleep.
*/
void
os_time_sleep(int64_t usecs);
/*
* Helper function for detecting time outs, taking in account overflow.
*
* Returns true if the current time has elapsed beyond the specified interval.
*/
static inline bool
os_time_timeout(int64_t start,
int64_t end,
int64_t curr)
{
if (start <= end)
return !(start <= curr && curr < end);
else
return !((start <= curr) || (curr < end));
}
/**
* Convert a relative timeout in nanoseconds into an absolute timeout,
* in other words, it returns current time + timeout.
* os_time_get_nano() must be monotonic.
* OS_TIMEOUT_INFINITE is passed through unchanged. If the calculation
* overflows, OS_TIMEOUT_INFINITE is returned.
*/
int64_t
os_time_get_absolute_timeout(uint64_t timeout);
/**
* Wait until the variable at the given memory location is zero.
*
* \param var variable
* \param timeout timeout in ns, can be anything from 0 (no wait) to
* OS_TIMEOUT_INFINITE (wait forever)
* \return true if the variable is zero
*/
bool
os_wait_until_zero(volatile int *var, uint64_t timeout);
/**
* Wait until the variable at the given memory location is zero.
* The timeout is the absolute time when the waiting should stop. If it is
* less than or equal to the current time, it only returns the status and
* doesn't wait. OS_TIMEOUT_INFINITE waits forever. This requires that
* os_time_get_nano is monotonic.
*
* \param var variable
* \param timeout the time in ns when the waiting should stop
* \return true if the variable is zero
*/
bool
os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout);
#ifdef __cplusplus
}
#endif
#endif /* _OS_TIME_H_ */
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