File content as of revision 2:4480021e9f58:

/*
 * Software License Agreement (BSD License)
 *
 * Copyright (c) 2011, Willow Garage, Inc.
 * 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 Willow Garage, Inc. nor the names of its
 *    contributors may be used to endorse or promote prducts 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 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <math.h>
#include "ros/duration.h"

namespace ros
{
void normalizeSecNSecSigned(int32_t &sec, int32_t &nsec)
{
  int32_t nsec_part = nsec;
  int32_t sec_part = sec;

  while (nsec_part > 1000000000L)
  {
    nsec_part -= 1000000000L;
    ++sec_part;
  }
  while (nsec_part < 0)
  {
    nsec_part += 1000000000L;
    --sec_part;
  }
  sec = sec_part;
  nsec = nsec_part;
}

Duration& Duration::operator+=(const Duration &rhs)
{
  sec += rhs.sec;
  nsec += rhs.nsec;
  normalizeSecNSecSigned(sec, nsec);
  return *this;
}

Duration& Duration::operator-=(const Duration &rhs)
{
  sec += -rhs.sec;
  nsec += -rhs.nsec;
  normalizeSecNSecSigned(sec, nsec);
  return *this;
}

Duration& Duration::operator*=(double scale)
{
  sec *= scale;
  nsec *= scale;
  normalizeSecNSecSigned(sec, nsec);
  return *this;
}

}