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.

helpers/LogHelper.cpp

@@ -0,0 +1,128 @@
+/*
+	This file is part of EqualizerAPO, a system-wide equalizer.
+	Copyright (C) 2012  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 <cstdarg>
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+#include "RegistryHelper.h"
+#include "LogHelper.h"
+
+using namespace std;
+
+bool LogHelper::initialized = false;
+wstring LogHelper::logPath;
+bool LogHelper::enableTrace = false;
+FILE* LogHelper::presetFP = NULL;
+bool LogHelper::compact = false;
+bool LogHelper::useConsoleColors = false;
+
+void LogHelper::log(const char* file, int line, const void* caller, bool trace, const wchar_t* format, ...)
+{
+	if(!initialized)
+	{
+		//Do not try to initialize again, even in case of error
+		initialized = true;
+
+		wchar_t temp[255];
+		GetTempPathW(sizeof(temp)/sizeof(wchar_t), temp);
+
+		logPath = temp;
+		logPath += L"EqualizerAPO.log";
+
+		try
+		{
+			if(RegistryHelper::readValue(APP_REGPATH, L"EnableTrace") != L"false")
+				enableTrace = true;
+		}
+		catch(RegistryException e)
+		{
+			LogFStatic(L"%s", e.getMessage());
+		}
+	}
+
+	if(trace && !enableTrace)
+		return;
+
+	FILE* fp;
+	if(presetFP == NULL)
+	{
+		errno_t err = _wfopen_s(&fp, logPath.c_str(), L"at");
+		if(err != 0)
+			return;
+	}
+	else
+	{
+		fp = presetFP;
+	}
+
+	if(useConsoleColors)
+	{
+		HANDLE con = GetStdHandle(STD_OUTPUT_HANDLE);
+		if(trace)
+			SetConsoleTextAttribute(con, 2); // Set console color to green
+		else
+			SetConsoleTextAttribute(con, 12); // Set console color to red
+	}
+
+	if(!compact)
+	{
+		SYSTEMTIME ___st;
+		GetLocalTime(&___st);
+		DWORD threadId = GetCurrentThreadId();
+		fwprintf(fp, L"%04d-%02d-%02d %02d:%02d:%02d.%03d %d %08X (%S:%d): ",
+			___st.wYear, ___st.wMonth, ___st.wDay, ___st.wHour, ___st.wMinute, ___st.wSecond, ___st.wMilliseconds, threadId, caller, file, line);
+	}
+
+	if(trace)
+		fwprintf(fp, L"(TRACE) ");
+
+	va_list varArgs;
+	va_start(varArgs, format);
+	vfwprintf(fp, format, varArgs);
+	va_end(varArgs);
+
+	fwprintf(fp, L"\n");
+
+	if(useConsoleColors)
+	{
+		HANDLE con = GetStdHandle(STD_OUTPUT_HANDLE);
+		SetConsoleTextAttribute(con, 7); // Set console color to light grey (default)
+	}
+
+	if(presetFP == NULL)
+		fclose(fp);
+}
+
+void LogHelper::reset()
+{
+	initialized = false;
+	logPath = L"";
+	enableTrace = false;
+}
+
+void LogHelper::set(FILE* fp, bool enableTrace, bool compact, bool useConsoleColors)
+{
+	LogHelper::initialized = true;
+
+	LogHelper::presetFP = fp;
+	LogHelper::enableTrace = enableTrace;
+	LogHelper::compact = compact;
+	LogHelper::useConsoleColors = useConsoleColors;
+}