forked from premiere/premiere-libtorrent
110 lines
3.0 KiB
C++
110 lines
3.0 KiB
C++
/*
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Copyright (c) 2010-2014, Arvid Norberg
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_SLIDING_AVERAGE_HPP_INCLUDED
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#define TORRENT_SLIDING_AVERAGE_HPP_INCLUDED
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namespace libtorrent
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{
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// a sliding average accumulator. Add samples to it and it
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// keeps track of a sliding mean value and an average deviation
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template <int history_size>
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struct sliding_average
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{
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sliding_average(): m_mean(-1), m_average_deviation(-1) {}
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void add_sample(int s)
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{
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TORRENT_ASSERT(s >= 0);
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if (s < 0) s = 0;
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if (m_mean == -1)
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{
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m_mean = s;
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return;
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}
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int deviation = abs(m_mean - s);
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m_mean = m_mean - m_mean / history_size + s / history_size;
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if (m_average_deviation == -1)
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{
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m_average_deviation = deviation;
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return;
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}
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m_average_deviation = m_average_deviation - m_average_deviation
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/ history_size + deviation / history_size;
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}
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int mean() const { return m_mean != -1 ? m_mean : 0; }
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int avg_deviation() const { return m_average_deviation != -1 ? m_average_deviation : 0; }
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private:
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int m_mean;
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int m_average_deviation;
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};
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struct average_accumulator
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{
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average_accumulator()
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: m_num_samples(0)
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, m_sample_sum(0)
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{}
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void add_sample(int s)
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{
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++m_num_samples;
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m_sample_sum += s;
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}
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int mean()
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{
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int ret;
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if (m_num_samples == 0) ret = 0;
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else ret = int(m_sample_sum / m_num_samples);
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// in case we don't get any more samples, at least
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// let the average roll over, but only be worth a
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// single sample
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m_num_samples = 1;
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m_sample_sum = ret;
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return ret;
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}
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int m_num_samples;
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size_type m_sample_sum;
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};
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}
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#endif
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