93 lines
2.4 KiB
C++
93 lines
2.4 KiB
C++
/*
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This file is part of EqualizerAPO, a system-wide equalizer.
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Copyright (C) 2015 Jonas Thedering
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "stdafx.h"
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#include <algorithm>
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#include "GainIterator.h"
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using namespace std;
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GainIterator::GainIterator(const vector<FilterNode>& nodes)
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{
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this->nodes = nodes;
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nodeLeft = NULL;
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nodeRight = NULL;
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}
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double GainIterator::gainAt(double freq)
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{
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if (nodeLeft == NULL && nodeRight == NULL || nodeLeft != NULL && freq < nodeLeft->freq)
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{
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FilterNode findNode(freq, 0);
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vector<FilterNode>::iterator it = lower_bound(nodes.begin(), nodes.end(), findNode);
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if (it != nodes.begin())
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nodeLeft = &*(it - 1);
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if (it != nodes.end())
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nodeRight = &*it;
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if (nodeLeft != NULL && nodeRight != NULL)
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{
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logLeft = log(nodeLeft->freq);
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logRightMinusLeft = log(nodeRight->freq) - logLeft;
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}
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}
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else if (nodeRight != NULL && freq > nodeRight->freq)
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{
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vector<FilterNode>::iterator it = nodes.begin() + (nodeRight - &*nodes.begin());
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while (it != nodes.end() && freq > it->freq)
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{
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it++;
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}
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if (it == nodes.end())
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nodeRight = NULL;
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else
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nodeRight = &*it;
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if (it != nodes.begin())
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nodeLeft = &*(it - 1);
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if (nodeLeft != NULL && nodeRight != NULL)
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{
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logLeft = log(nodeLeft->freq);
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logRightMinusLeft = log(nodeRight->freq) - logLeft;
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}
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}
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double dbGain;
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if (nodeLeft == NULL)
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{
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if (nodeRight == NULL)
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dbGain = 0.0;
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else
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dbGain = nodeRight->dbGain;
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}
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else if (nodeRight == NULL)
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{
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dbGain = nodeLeft->dbGain;
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}
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else
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{
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double t = (log(freq) - logLeft) / logRightMinusLeft;
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dbGain = nodeLeft->dbGain + t * (nodeRight->dbGain - nodeLeft->dbGain);
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}
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return dbGain;
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}
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