Version 1.0

Added: Configuration Editor, which allows to edit configurations in a graphical user interface. Contains GUIs for most commands supported by E-APO, but as lines can also be edited directly, all commands can be used.
Added: Command "GraphicEQ", which can act as a regular, fixed-band graphic equalizer (via the GUI) but also supports variable bands so that any desired frequency response can be specified. Internally, it is implemented via convolution with a generated IR.
Added: Command "Convolution", which allows to convolve the signal with a user-provided impulse response to achieve e.g. equalization or reverberation effects.
Improved: Configurator performs checks for registry values that are needed for the operation of E-APO, which may be changed by driver installations, fixing the values if necessary.
Improved: Configurator shows which is the default device as a hint to the user.

helpers/GainIterator.cpp

@@ -0,0 +1,92 @@
+/*
+	This file is part of EqualizerAPO, a system-wide equalizer.
+	Copyright (C) 2015  Jonas Thedering
+
+	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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "stdafx.h"
+#include <algorithm>
+
+#include "GainIterator.h"
+
+using namespace std;
+
+GainIterator::GainIterator(const vector<FilterNode>& nodes)
+{
+	this->nodes = nodes;
+	nodeLeft = NULL;
+	nodeRight = NULL;
+}
+
+double GainIterator::gainAt(double freq)
+{
+	if(nodeLeft == NULL && nodeRight == NULL || nodeLeft != NULL && freq < nodeLeft->freq)
+	{
+		FilterNode findNode(freq, 0);
+		vector<FilterNode>::iterator it = lower_bound(nodes.begin(), nodes.end(), findNode);
+		if(it != nodes.begin())
+			nodeLeft = &*(it - 1);
+		if(it != nodes.end())
+			nodeRight = &*it;
+
+		if(nodeLeft != NULL && nodeRight != NULL)
+		{
+			logLeft = log(nodeLeft->freq);
+			logRightMinusLeft = log(nodeRight->freq) - logLeft;
+		}
+	}
+	else if(nodeRight != NULL && freq > nodeRight->freq)
+	{
+		vector<FilterNode>::iterator it = nodes.begin() + (nodeRight - &*nodes.begin());
+		while(it != nodes.end() && freq > it->freq)
+		{
+			it++;
+		}
+		if(it == nodes.end())
+			nodeRight = NULL;
+		else
+			nodeRight = &*it;
+
+		if(it != nodes.begin())
+			nodeLeft = &*(it - 1);
+
+		if(nodeLeft != NULL && nodeRight != NULL)
+		{
+			logLeft = log(nodeLeft->freq);
+			logRightMinusLeft = log(nodeRight->freq) - logLeft;
+		}
+	}
+
+	double dbGain;
+	if(nodeLeft == NULL)
+	{
+		if(nodeRight == NULL)
+			dbGain = 0.0;
+		else
+			dbGain = nodeRight->dbGain;
+	}
+	else if(nodeRight == NULL)
+	{
+		dbGain = nodeLeft->dbGain;
+	}
+	else
+	{
+		double t = (log(freq) - logLeft) / logRightMinusLeft;
+		dbGain = nodeLeft->dbGain + t * (nodeRight->dbGain - nodeLeft->dbGain);
+	}
+
+	return dbGain;
+}