/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program 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; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program 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 General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/timeUtils.h#5 $

 */

#ifndef TIME_UTILS_H

#define TIME_UTILS_H

#include "compiler.h"

#include "typeDefs.h"

#ifdef __KERNEL__

#include <linux/ktime.h>

#include <linux/time.h>

#else

#include <sys/time.h>

#include <time.h>

#endif

// Absolute time.

#ifdef __KERNEL__

typedef int64_t AbsTime;

#else

typedef struct timespec AbsTime;

#endif

// Relative time, the length of a time interval, or the difference between

// two times.  A signed 64-bit number of nanoseconds.

typedef int64_t RelTime;

#ifndef __KERNEL__

/**

 * Return true if the time is valid.

 *

 * @param time  a time

 *

 * @return true if the time is valid

 *

 * @note an invalid time is generally returned from a failed attempt

 *      to get the time from the system

 **/

bool isValidTime(AbsTime time);

#endif

/**

 * Return the current time according to the specified clock type.

 *

 * @param clock         Either CLOCK_REALTIME or CLOCK_MONOTONIC

 *

 * @return the current time according to the clock in question

 *

 * @note the precision of the clock is system specific

 **/

#ifdef __KERNEL__

static INLINE AbsTime currentTime(clockid_t clock)

{

  // clock is always a constant, so gcc reduces this to a single call

  return clock == CLOCK_MONOTONIC ? ktime_get_ns() : ktime_get_real_ns();

}

#else

AbsTime currentTime(clockid_t clock);

#endif

#ifndef __KERNEL__

/**

 * Return the timestamp a certain number of nanoseconds in the future.

 *

 * @param clock    Either CLOCK_REALTIME or CLOCK_MONOTONIC

 * @param reltime  The relative time to the clock value

 *

 * @return the timestamp for that time (potentially rounded to the next

 *         representable instant for the system in question)

 **/

AbsTime futureTime(clockid_t clock, RelTime reltime);

#endif

/**

 * Return the difference between two timestamps.

 *

 * @param a  A time

 * @param b  Another time, based on the same clock as a.

 *

 * @return the relative time between the two timestamps

 **/

#ifdef __KERNEL__

static INLINE RelTime timeDifference(AbsTime a, AbsTime b)

{

  return a - b;

}

#else

RelTime timeDifference(AbsTime a, AbsTime b);

#endif

/**

 * Convert seconds to a RelTime value

 *

 * @param seconds  A number of seconds

 *

 * @return the equivalent number of seconds as a RelTime

 **/

static INLINE RelTime secondsToRelTime(int64_t seconds)

{

  return (RelTime) seconds * (1000 * 1000 * 1000);

}

/**

 * Convert milliseconds to a RelTime value

 *

 * @param milliseconds  A number of milliseconds

 *

 * @return the equivalent number of milliseconds as a RelTime

 **/

static INLINE RelTime millisecondsToRelTime(int64_t milliseconds)

{

  return (RelTime) milliseconds * (1000 * 1000);

}

/**

 * Convert microseconds to a RelTime value

 *

 * @param microseconds  A number of microseconds

 *

 * @return the equivalent number of microseconds as a RelTime

 **/

static INLINE RelTime microsecondsToRelTime(int64_t microseconds)

{

  return (RelTime) microseconds * 1000;

}

/**

 * Convert nanoseconds to a RelTime value

 *

 * @param nanoseconds  A number of nanoseconds

 *

 * @return the equivalent number of nanoseconds as a RelTime

 **/

static INLINE RelTime nanosecondsToRelTime(int64_t nanoseconds)

{

  return (RelTime) nanoseconds;

}

/**

 * Convert a RelTime value to milliseconds

 *

 * @param reltime  The relative time

 *

 * @return the equivalent number of milliseconds

 **/

static INLINE int64_t relTimeToSeconds(RelTime reltime)

{

  return reltime / (1000 * 1000 * 1000);

}

/**

 * Convert a RelTime value to milliseconds

 *

 * @param reltime  The relative time

 *

 * @return the equivalent number of milliseconds

 **/

static INLINE int64_t relTimeToMilliseconds(RelTime reltime)

{

  return reltime / (1000 * 1000);

}

/**

 * Convert a RelTime value to microseconds

 *

 * @param reltime  The relative time

 *

 * @return the equivalent number of microseconds

 **/

static INLINE int64_t relTimeToMicroseconds(RelTime reltime)

{

  return reltime / 1000;

}

/**

 * Convert a RelTime value to nanoseconds

 *

 * @param reltime  The relative time

 *

 * @return the equivalent number of nanoseconds

 **/

static INLINE int64_t relTimeToNanoseconds(RelTime reltime)

{

  return reltime;

}

/**

 * Return the wall clock time in microseconds. The actual value is time

 * since the epoch (see "man gettimeofday"), but the typical use is to call

 * this twice and compute the difference, giving the elapsed time between

 * the two calls.

 *

 * @return the time in microseconds

 **/

uint64_t nowUsec(void) __attribute__((warn_unused_result));

/**

 * Convert from an AbsTime to a time_t

 *

 * @param time  an AbsTime time

 *

 * @return a time_t time

 **/

static INLINE time_t asTimeT(AbsTime time)

{

#ifdef __KERNEL__

  return time / 1000000000;

#else

  return time.tv_sec;

#endif

}

/**

 * Convert from a time_t to an AbsTime,

 *

 * @param time  a time_t time

 *

 * @return an AbsTime time

 **/

static INLINE AbsTime fromTimeT(time_t time)

{

#ifdef __KERNEL__

  return time * 1000000000;

#else

  AbsTime abs;

  abs.tv_sec = time;

  abs.tv_nsec = 0;

  return abs;

#endif

}

#ifndef __KERNEL__

/**

 * Convert from an AbsTime to a struct timespec

 *

 * @param time  an AbsTime time

 *

 * @return a time_t time

 **/

static INLINE struct timespec asTimeSpec(AbsTime time)

{

  return time;

}

#endif

#ifndef __KERNEL__

/**

 * Convert from an AbsTime to a struct timeval

 *

 * @param time  an AbsTime time

 *

 * @return a time_t time

 **/

static INLINE struct timeval asTimeVal(AbsTime time)

{

  struct timeval tv = { time.tv_sec, time.tv_nsec / 1000 };

  return tv;

}

#endif

#endif /* TIME_UTILS_H */