icinga2/lib/base/ringbuffer.cpp

109 lines
3.3 KiB
C++

/******************************************************************************
* Icinga 2 *
* Copyright (C) 2012-2018 Icinga Development Team (https://www.icinga.com/) *
* *
* 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 St, Fifth Floor, Boston, MA 02110-1301, USA. *
******************************************************************************/
#include "base/ringbuffer.hpp"
#include "base/objectlock.hpp"
#include "base/utility.hpp"
#include <algorithm>
using namespace icinga;
RingBuffer::RingBuffer(RingBuffer::SizeType slots)
: m_Slots(slots, 0), m_TimeValue(0), m_InsertedValues(0)
{ }
RingBuffer::SizeType RingBuffer::GetLength() const
{
boost::mutex::scoped_lock lock(m_Mutex);
return m_Slots.size();
}
void RingBuffer::InsertValue(RingBuffer::SizeType tv, int num)
{
boost::mutex::scoped_lock lock(m_Mutex);
InsertValueUnlocked(tv, num);
}
void RingBuffer::InsertValueUnlocked(RingBuffer::SizeType tv, int num)
{
RingBuffer::SizeType offsetTarget = tv % m_Slots.size();
if (m_TimeValue == 0)
m_InsertedValues = 1;
if (tv > m_TimeValue) {
RingBuffer::SizeType offset = m_TimeValue % m_Slots.size();
/* walk towards the target offset, resetting slots to 0 */
while (offset != offsetTarget) {
offset++;
if (offset >= m_Slots.size())
offset = 0;
m_Slots[offset] = 0;
if (m_TimeValue != 0 && m_InsertedValues < m_Slots.size())
m_InsertedValues++;
}
m_TimeValue = tv;
}
m_Slots[offsetTarget] += num;
}
int RingBuffer::UpdateAndGetValues(RingBuffer::SizeType tv, RingBuffer::SizeType span)
{
boost::mutex::scoped_lock lock(m_Mutex);
return UpdateAndGetValuesUnlocked(tv, span);
}
int RingBuffer::UpdateAndGetValuesUnlocked(RingBuffer::SizeType tv, RingBuffer::SizeType span)
{
InsertValueUnlocked(tv, 0);
if (span > m_Slots.size())
span = m_Slots.size();
int off = m_TimeValue % m_Slots.size();
int sum = 0;
while (span > 0) {
sum += m_Slots[off];
if (off == 0)
off = m_Slots.size();
off--;
span--;
}
return sum;
}
double RingBuffer::CalculateRate(RingBuffer::SizeType tv, RingBuffer::SizeType span)
{
boost::mutex::scoped_lock lock(m_Mutex);
int sum = UpdateAndGetValuesUnlocked(tv, span);
return sum / static_cast<double>(std::min(span, m_InsertedValues));
}