root/trunk/whisperlib/common/base/timer.h

// Copyright (c) 2009, Whispersoft s.r.l.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Whispersoft s.r.l. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
// OWNER 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
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//
// Author: Cosmin Tudorache

#ifndef __COMMON_BASE_TIMER_H__
#define __COMMON_BASE_TIMER_H__

#include <time.h>
#include <whisperlib/common/base/types.h>

namespace timer {

// returns: nanoseconds since an unspecified point in the past (for example,
//          system start-up time, or the Epoch). (uses CLOCK_MONOTONIC)
//          This value is not affected by sytem time changes and therefore
//          offers a reliable way of measuring time intervals.
int64 TicksNsec();

// returns: microseconds since an unspecified point in the past (for example,
// system start-up time, or the Epoch) (uses CLOCK_MONOTONIC)
inline int64 TicksUsec() {
  return TicksNsec() / 1000LL;
}
// returns: miliseconds since an unspecified point in the past (for example,
// system start-up time, or the Epoch) (uses CLOCK_MONOTONIC)
inline int64 TicksMsec() {
  return TicksNsec() / 1000000LL;
}

// Make the calling thread Sleep for "miliseconds" miliseconds.
// This call ignores signals.
void SleepMsec(int32 miliseconds);

// Returns a timespec that counts for the given milisecond interval
struct timespec TimespecFromMsec(int64 miliseconds);

// Reversed operation
int64 TimespecToMsec(struct timespec ts);


// Set moment: NOW + "shift_up_miliseconds"
// These methods should never fail. The only possbile failure is:
//  - uses CLOCK_REALTIME is not supported on this system, case when the
//    program will abort().
void SetTimespecAbsoluteMsec(struct timespec *ts,
                             int64 shift_up_miliseconds);
// Same as SetTimespecAbsoluteMsec but w/ a timestamp for interval
void SetTimespecAbsoluteTimespec(struct timespec* ts,
                                 const struct timespec& delta_ts);

// Another interface for SetTimespecAbsoluteMsec;
struct timespec TimespecAbsoluteMsec(int64 shift_up_miliseconds);

// Another interface for SetTimespecAbsoluteTimespec
void TimespecAbsoluteTimespec(struct timespec* ts,
                              const struct timespec& delta_ts);
}

#endif  // __COMMON_BASE_TIMER_H__