Version 0.9

Added: Filter type "IIR", which allows to specify a user-defined IIR filter of arbitrary order with custom coefficients.
Improved: For playback devices, the APO is now installed both as GFX (post-mix) and LFX (pre-mix) APO. Normally the filtering happens in GFX, but the command "Stage" allows to select LFX to apply effects based on the number of input channels.
Added: Expression language. The commands "If", "ElseIf", "Else", "EndIf", "Eval" and inline expressions allow to change the filter behaviour based on runtime conditions.
Added: Command "Copy", which copies audio data between channels.
Added: Command "Delay", which delays the audio on the currently selected channels.
Improved: Configuration files are now locked exclusively for writing while reading them.
Improved: There is now a transition (10 ms) from old to new configuration after loading.
Improved: Substantial internal restructuring to improve extensibility and maintainability. Filtering commands now work exactly in the order they were specified.
Fixed: When the microphone input was in stereo but the application requested a mono stream, the audio was heavily distorted.
Fixed: The sine sweep generated by the Benchmark application had floating-point precision issues leading to severe artifacts when certain filters were applied.

filters/IfFilterFactory.cpp

@@ -0,0 +1,211 @@
+/*
+	This file is part of EqualizerAPO, a system-wide equalizer.
+	Copyright (C) 2014  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 "helpers/LogHelper.h"
+#include "helpers/StringHelper.h"
+#include "parser/RegexFunctions.h"
+#include "parser/RegistryFunctions.h"
+#include "FilterEngine.h"
+#include "IfFilterFactory.h"
+
+using namespace std;
+using namespace mup;
+
+void IfFilterFactory::initialize(FilterEngine* engine)
+{
+	parser = engine->getParser();
+}
+
+vector<IFilter*> IfFilterFactory::startOfConfiguration()
+{
+	trueCount = 0;
+	falseCount = 0;
+	while(!trueCountStack.empty())
+		trueCountStack.pop();
+
+	return vector<IFilter*>();
+}
+
+std::vector<IFilter*> IfFilterFactory::startOfFile(const std::wstring& configPath)
+{
+	trueCountStack.push(trueCount);
+	trueCount = 0;
+	if(falseCount != 0)
+	{
+		LogF(L"File was included inside If that evaluated to false!");
+		falseCount = 0;
+	}
+
+	return vector<IFilter*>();
+}
+
+vector<IFilter*> IfFilterFactory::createFilter(const wstring& configPath, wstring& command, wstring& parameters)
+{
+	wstring expression = StringHelper::trim(parameters);
+
+	if(command == L"If")
+	{
+		if(falseCount == 0)
+		{
+			try
+			{
+				parser->SetExpr(expression);
+				Value result = parser->Eval();
+				bool isTrue = toBoolean(result);
+				if(result.GetType() == L'b')
+					TraceF(L"If(%s) evaluated to %s", expression.c_str(), result.ToString().c_str());
+				else
+					TraceF(L"If(%s) evaluated to %s (%s)", expression.c_str(), result.ToString().c_str(), isTrue ? L"true" : L"false");
+
+				if(isTrue)
+					trueCount++;
+				else
+					falseCount++;
+			}
+			catch(ParserError e)
+			{
+				LogF(L"Error while evaluating If(%s): %s", expression.c_str(), e.GetMsg().c_str());
+				falseCount++;
+			}
+		}
+		else
+		{
+			falseCount++;
+		}
+	}
+	else if(command == L"ElseIf")
+	{
+		if(falseCount == 1)
+		{
+			try
+			{
+				parser->SetExpr(expression);
+				Value result = parser->Eval();
+				bool isTrue = toBoolean(result);
+				if(result.GetType() == L'b')
+					TraceF(L"ElseIf(%s) evaluated to %s", expression.c_str(), result.ToString().c_str());
+				else
+					TraceF(L"ElseIf(%s) evaluated to %s (%s)", expression.c_str(), result.ToString().c_str(), isTrue ? L"true" : L"false");
+
+				if(isTrue)
+				{
+					falseCount--;
+					trueCount++;
+				}
+			}
+			catch(ParserError e)
+			{
+				LogF(L"Error while evaluating ElseIf(%s): %s", expression.c_str(), e.GetMsg().c_str());
+			}
+		}
+		else if(falseCount == 0 && trueCount == 0)
+		{
+			LogF(L"ElseIf without If!");
+		}
+	}
+	else if(command == L"Else")
+	{
+		if(falseCount == 1)
+		{
+			falseCount--;
+			trueCount++;
+		}
+		else if(falseCount == 0 && trueCount == 0)
+		{
+			LogF(L"Else without If!");
+		}
+	}
+	else if(command == L"EndIf")
+	{
+		if(falseCount == 0)
+		{
+			if(trueCount == 0)
+				LogF(L"EndIf without If!");
+			else
+				trueCount--;
+		}
+		else
+		{
+			falseCount--;
+		}
+	}
+
+	if(falseCount > 0)
+		// skip line for further factories
+		command = L"";
+
+	return vector<IFilter*>();
+}
+
+std::vector<IFilter*> IfFilterFactory::endOfFile(const std::wstring& configPath)
+{
+	if(trueCount != 0 || falseCount != 0)
+	{
+		LogF(L"If was not closed by EndIf!");
+		falseCount = 0;
+	}
+	trueCount = trueCountStack.top();
+	trueCountStack.pop();
+
+	return vector<IFilter*>();
+}
+
+bool IfFilterFactory::toBoolean(const Value& value)
+{
+	bool result = false;
+
+	wchar_t type = value.GetType();
+	switch(type)
+	{
+	case 'i':
+		{
+			int i = value.GetInteger();
+			result = (i != 0);
+		}
+		break;
+	case 'f':
+		{
+			double f = value.GetFloat();
+			result = (f != 0.0 && f == f);
+		}
+		break;
+	case 'b':
+		{
+			result = value.GetBool();
+		}
+		break;
+	case 's':
+		{
+			wstring s = value.GetString();
+			result = s.length() > 0 && s != L"false" && s != L"0";
+		}
+		break;
+	case 'm':
+		{
+			Matrix<Value> m = value.GetArray();
+			result = m.GetRows() > 0 && m.GetCols() > 0;
+		}
+		break;
+	default:
+		result = false;
+		break;
+	}
+
+	return result;
+}