Registry.h

// JPEGsnoop - JPEG Image Decoder & Analysis Utility
// Copyright (C) 2017 - Calvin Hass
// http://www.impulseadventure.com/photo/jpeg-snoop.html
//
//    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, see <http://www.gnu.org/licenses/>.
//

// ====================================================================================================
// SOURCE CODE ACKNOWLEDGEMENT
// ====================================================================================================
// The following code is derived from the following project on CodeProject:
//
//		Title:		Another registry class
//		Author:		SteveKing
//		URL:		http://www.codeproject.com/Articles/2521/Another-registry-class
//		Date:		Apr 25, 2003
//		License:	CPOL (Code Project Open License)
//
// ====================================================================================================

#pragma once
#include <string>
#include <Shlwapi.h>
#include <tchar.h>
#ifdef _MFC_VER

/**
 * \ingroup CommonClasses
 * Base class for the registry classes.
 *
 * \par requirements 
 * - win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * - import library Shlwapi.lib
 *
 * \author Stefan Kueng
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.0 
 * \date 06-2002
 * \todo
 * \bug
 * \warning
 *
 */
class CRegBase
{
public:	//methods
	/**
	 * Removes the whole registry key including all values. So if you set the registry
	 * entry to be HKCU\Software\Company\Product\key\value there will only be
	 * HKCU\Software\Company\Product key in the registry.
	 * \return ERROR_SUCCESS or an nonzero errorcode. Use FormatMessage() to get an error description.
	 */
	DWORD removeKey() { RegOpenKeyEx(m_base, m_path, 0, KEY_WRITE, &m_hKey); return SHDeleteKey(m_base, (LPCTSTR)m_path); }
	/**
	 * Removes the value of the registry object. If you set the registry entry to
	 * be HKCU\Software\Company\Product\key\value there will only be
	 * HKCU\Software\Company\Product\key\ in the registry.
	 * \return ERROR_SUCCESS or an nonzero errorcode. Use FormatMessage() to get an error description.
	 */
	LONG removeValue() { RegOpenKeyEx(m_base, m_path, 0, KEY_WRITE, &m_hKey); return RegDeleteValue(m_hKey, (LPCTSTR)m_key); }

public:	//members
	HKEY m_base;		///< handle to the registry base
	HKEY m_hKey;		///< handle to the open registry key
	CString m_key;		///< the name of the value
	CString m_path;		///< the path to the key
};

/**
 * \ingroup CommonClasses
 * DWORD value in registry. with this class you can use DWORD values in registry
 * like normal DWORD variables in your program.
 * Usage:
 * in your header file, declare your registry DWORD variable:
 * \code
 * CRegDWORD regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegDWORD("Software\\Company\\SubKey\\MyValue", 100);
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of 100 is used when accessing the variable.
 * now the variable can be used like any other DWORD variable:
 * \code
 * regvalue = 200;						//stores the value 200 in the registry
 * int temp = regvalue + 300;			//temp has value 500 now
 * regvalue += 300;						//now the registry has the value 500 too
 * \endcode
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng (stefan_kueng@catv.rol.ch)
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.1
 * added base class CRegBase with methods removeKey() and removeValue()
 * \version 1.0 
 * \date 06-2002
 * \todo
 * \bug
 * \warning
 *
 */
class CRegDWORD : public CRegBase
{
public:
	CRegDWORD(void);
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegDWORD(CString key, DWORD def = 0, BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegDWORD(void);
	/**
	 * reads the assigned value from the registry. Use this method only if you think the registry
	 * value could have been altered without using the CRegDWORD object.
	 * \return the read value
	 */
	DWORD	read();						///< reads the value from the registry
	void	write();					///< writes the value to the registry

	operator DWORD();
	CRegDWORD& operator=(DWORD d);
	CRegDWORD& operator+=(DWORD d) { return *this = *this + d;}
	CRegDWORD& operator-=(DWORD d) { return *this = *this - d;}
	CRegDWORD& operator*=(DWORD d) { return *this = *this * d;}
	CRegDWORD& operator/=(DWORD d) { return *this = *this / d;}
	CRegDWORD& operator%=(DWORD d) { return *this = *this % d;}
	CRegDWORD& operator<<=(DWORD d) { return *this = *this << d;}
	CRegDWORD& operator>>=(DWORD d) { return *this = *this >> d;}
	CRegDWORD& operator&=(DWORD d) { return *this = *this & d;}
	CRegDWORD& operator|=(DWORD d) { return *this = *this | d;}
	CRegDWORD& operator^=(DWORD d) { return *this = *this ^ d;}
	
protected:

	DWORD	m_value;					///< the cached value of the registry
	DWORD	m_defaultvalue;				///< the default value to use
	BOOL	m_read;						///< indicates if the value has already been read from the registry
	BOOL	m_force;					///< indicates if no cache should be used, i.e. always read and write directly from registry
};

/**
 * \ingroup CommonClasses
 * CString value in registry. with this class you can use CString values in registry
 * almost like normal CString variables in your program.
 * Usage:
 * in your header file, declare your registry CString variable:
 * \code
 * CRegString regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegString("Software\\Company\\SubKey\\MyValue", "default");
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of "default" is used when accessing the variable.
 * now the variable can be used like any other CString variable:
 * \code
 * regvalue = "some string";			//stores the value "some string" in the registry
 * CString temp = regvalue + "!!";		//temp has value "some string!!" now
 * \endcode
 * to use the normal methods of the CString class, just typecast the CRegString to a CString
 * and do whatever you want with the string:
 * \code
 * ((CString)regvalue).GetLength();
 * ((CString)regvalue).Trim();
 * \endcode
 * please be aware that in the second line the change in the string won't be written
 * to the registry! To force a write use the write() method. A write() is only needed
 * if you change the String with Methods not overloaded by CRegString.
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng (stefan_kueng@catv.rol.ch)
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.1
 * corrected a bug, thanks to Hans Dietrich for the correction.
 * added base class CRegBase with methods removeKey() and removeValue()
 * \version 1.0 
 * \date 06-2002
 * \todo
 * \bug
 * \warning
 */
class CRegString : public CRegBase
{
public:
	CRegString();
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegString(CString key, CString def = _T(""), BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegString(void);
	
	CString read();						///< reads the value from the registry
	void	write();					///< writes the value to the registry
		
	operator CString();
	CRegString& operator=(CString s);
	CRegString& operator+=(CString s) { return *this = (CString)*this + s; }
	
	
	
protected:

	CString	m_value;					///< the cached value of the registry
	CString	m_defaultvalue;				///< the default value to use
	BOOL	m_read;						///< indicates if the value has already been read from the registry
	BOOL	m_force;					///< indicates if no cache should be used, i.e. always read and write directly from registry
};

/**
 * \ingroup CommonClasses
 * CRect value in registry. with this class you can use CRect values in registry
 * almost like normal CRect variables in your program.
 * Usage:
 * in your header file, declare your registry CString variable:
 * \code
 * CRegRect regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegRect("Software\\Company\\SubKey\\MyValue", CRect(100,100,200,200));
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of 100,100,200,200 is used when accessing the variable.
 * now the variable can be used like any other CRect variable:
 * \code
 * regvalue = CRect(40,20,300,500);				//stores the value in the registry
 * CRect temp = regvalue + CPoint(1,1);
 * temp |= CSize(5,5);
 * \endcode
 * to use the normal methods of the CRect class, just typecast the CRegRect to a CRect
 * and do whatever you want with the rect:
 * \code
 * ((CRect)regvalue).MoveToX(100);
 * ((CRect)regvalue).DeflateRect(10,10);
 * \endcode
 * please be aware that in the second line the change in the CRect won't be written
 * to the registry! To force a write use the write() method. A write() is only needed
 * if you change the CRect with Methods not overloaded by CRegRect.
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng (stefan_kueng@catv.rol.ch)
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.1
 * corrected a bug, thanks to Hans Dietrich for the correction.
 * added base class CRegBase with methods removeKey() and removeValue()
 * \version 1.0 
 * \date 06-2002
 * \todo
 * \bug
 * \warning
 */
#if 0 // Remove CRegRect (unneeded, triggers C2440)
class CRegRect : public CRegBase
{
public:
	CRegRect();
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegRect(CString key, CRect def = CRect(), BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegRect(void);
	
	CRect read();						///< reads the value from the registry
	void	write();					///< writes the value to the registry
	
	operator CRect();
	operator LPCRECT() { return (LPCRECT)(CRect)*this; }
	operator LPRECT() { return (LPRECT)(CRect)*this; }
	CRegRect& operator=(CRect r);
	CRegRect& operator+=(POINT r) { return *this = (CRect)*this + r;}
	CRegRect& operator+=(SIZE r) { return *this = (CRect)*this + r;}
	CRegRect& operator+=(LPCRECT  r) { return *this = (CRect)*this + r;}
	CRegRect& operator-=(POINT r) { return *this = (CRect)*this - r;}
	CRegRect& operator-=(SIZE r) { return *this = (CRect)*this - r;}
	CRegRect& operator-=(LPCRECT  r) { return *this = (CRect)*this - r;}
	
	CRegRect& operator&=(CRect r) { return *this = r & *this;}
	CRegRect& operator|=(CRect r) { return *this = r | *this;}
	
	
protected:

	CRect	m_value;					///< the cached value of the registry
	CRect	m_defaultvalue;				///< the default value to use
	BOOL	m_read;						///< indicates if the value has already been read from the registry
	BOOL	m_force;					///< indicates if no cache should be used, i.e. always read and write directly from registry
};
#endif // Remove CRegRect

/**
 * \ingroup CommonClasses
 * CPoint value in registry. with this class you can use CPoint values in registry
 * almost like normal CPoint variables in your program.
 * Usage:
 * in your header file, declare your registry CPoint variable:
 * \code
 * CRegPoint regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegPoint("Software\\Company\\SubKey\\MyValue", CPoint(100,100));
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of 100,100 is used when accessing the variable.
 * now the variable can be used like any other CPoint variable:
 * \code
 * regvalue = CPoint(40,20);					//stores the value in the registry
 * CPoint temp = regvalue + CPoint(1,1);
 * temp += CSize(5,5);
 * \endcode
 * to use the normal methods of the CPoint class, just typecast the CRegPoint to a CPoint
 * and do whatever you want with the point:
 * \code
 * ((CRect)regvalue).Offset(100,10);
 * \endcode
 * please be aware that in the above example the change in the CPoint won't be written
 * to the registry! To force a write use the write() method. A write() is only needed
 * if you change the CPoint with Methods not overloaded by CRegPoint.
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng (stefan_kueng@catv.rol.ch)
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.1
 * corrected a bug, thanks to Hans Dietrich for the correction.
 * added base class CRegBase with methods removeKey() and removeValue()
 * \version 1.0 
 * \date 06-2002
 * \todo
 * \bug
 * \warning
 */
class CRegPoint : public CRegBase
{
public:
	CRegPoint();
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegPoint(CString key, CPoint def = CPoint(), BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegPoint(void);
	
	CPoint read();
	void	write();					///< writes the value to the registry
	
	operator CPoint();
	CRegPoint& operator=(CPoint p);
	
	CRegPoint& operator+=(CPoint p) { return *this = p + *this; }
	CRegPoint& operator-=(CPoint p) { return *this = p - *this; }
	
	
protected:

	CPoint	m_value;					///< the cached value of the registry
	CPoint	m_defaultvalue;				///< the default value to use
	BOOL	m_read;						///< indicates if the value has already been read from the registry
	BOOL	m_force;					///< indicates if no cache should be used, i.e. always read and write directly from registry
};

#endif

typedef std::basic_string<TCHAR> stdstring;

class CRegStdBase
{
public:	//methods
	/**
	 * Removes the whole registry key including all values. So if you set the registry
	 * entry to be HKCU\Software\Company\Product\key\value there will only be
	 * HKCU\Software\Company\Product key in the registry.
	 * \return ERROR_SUCCESS or an nonzero errorcode. Use FormatMessage() to get an error description.
	 */
	DWORD removeKey() { RegOpenKeyEx(m_base, m_path.c_str(), 0, KEY_WRITE, &m_hKey); return SHDeleteKey(m_base, m_path.c_str()); }
	/**
	 * Removes the value of the registry object. If you set the registry entry to
	 * be HKCU\Software\Company\Product\key\value there will only be
	 * HKCU\Software\Company\Product\key\ in the registry.
	 * \return ERROR_SUCCESS or an nonzero errorcode. Use FormatMessage() to get an error description.
	 */
	LONG removeValue() { RegOpenKeyEx(m_base, m_path.c_str(), 0, KEY_WRITE, &m_hKey); return RegDeleteValue(m_hKey, m_key.c_str()); }

public:	//members
	HKEY m_base;		///< handle to the registry base
	HKEY m_hKey;		///< handle to the open registry key
	stdstring m_key;		///< the name of the value
	stdstring m_path;		///< the path to the key
};

/**
 * \ingroup CommonClasses
 * std::string value in registry. with this class you can use std::string values in registry
 * almost like normal std::string variables in your program.
 * Usage:
 * in your header file, declare your registry std::string variable:
 * \code
 * CRegStdString regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegStdString("Software\\Company\\SubKey\\MyValue", "default");
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of "default" is used when accessing the variable.
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng (stefan_kueng@catv.rol.ch)
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.0
 * first version which uses std::string instead of CString.
 * \date 10-2002
 */
class CRegStdString : public CRegStdBase
{
public:
	CRegStdString();
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegStdString(stdstring key, stdstring def = _T(""), BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegStdString(void);
	
	stdstring read();						///< reads the value from the registry
	void	write();					///< writes the value to the registry
		
	operator stdstring();
	CRegStdString& operator=(stdstring s);
	//CAL! Commended out the following as otherwise we get error C2440. We don't
	//     use this function anyway.
	//CRegStdString& operator+=(stdstring s) { return *this = (stdstring)*this + s; }
	operator LPCTSTR();
	
	
protected:

	stdstring	m_value;				///< the cached value of the registry
	stdstring	m_defaultvalue;			///< the default value to use
	BOOL	m_read;						///< indicates if the value has already been read from the registry
	BOOL	m_force;					///< indicates if no cache should be used, i.e. always read and write directly from registry
};

/**
 * \ingroup CommonClasses
 * DWORD value in registry. with this class you can use DWORD values in registry
 * like normal DWORD variables in your program.
 * Usage:
 * in your header file, declare your registry DWORD variable:
 * \code
 * CRegStdWORD regvalue;
 * \endcode
 * next initialize the variable e.g. in the constructor of your class:
 * \code
 * regvalue = CRegStdWORD("Software\\Company\\SubKey\\MyValue", 100);
 * \endcode
 * this will set the registry value "MyValue" under HKEY_CURRENT_USER with path 
 * "Software\Company\SubKey" to the variable. If the key does not yet exist or
 * an error occured during read from the registry, a default
 * value of 100 is used when accessing the variable.
 * now the variable can be used like any other DWORD variable:
 * \code
 * regvalue = 200;						//stores the value 200 in the registry
 * int temp = regvalue + 300;			//temp has value 500 now
 * regvalue += 300;						//now the registry has the value 500 too
 * \endcode
 * to avoid too much access to the registry the value is cached inside the object.
 * once the value is read, no more read accesses to the registry will be made.
 * this means the variable will contain a wrong value if the corresponding registry
 * entry is changed by anything else than this variable! If you think that could happen
 * then use 
 * \code
 * regvalue.read();
 * \endcode
 * to force a refresh of the variable with the registry.
 * a write to the registry is only made if the new value assigned with the variable
 * is different than the last assigned value.
 * to force a write use the method write();
 * another option to force reads and writes to the registry is to specify TRUE as the
 * third parameter in the constructor.
 *
 * \par requirements 
 * win98 or later, win2k or later, win95 with IE4 or later, winNT4 with IE4 or later
 * import library Shlwapi.lib
 *
 * \author Stefan Kueng
 *
 * \par license 
 * This code is absolutely free to use and modify. The code is provided "as is" with
 * no expressed or implied warranty. The author accepts no liability if it causes
 * any damage to your computer, causes your pet to fall ill, increases baldness 
 * or makes your car start emitting strange noises when you start it up.
 * This code has no bugs, just undocumented features!
 * 
 * \version 1.0 
 * \date 11-2002
 * \todo
 * \bug
 * \warning
 *
 */
class CRegStdWORD : public CRegStdBase
{
public:
	CRegStdWORD();
	/**
	 * Constructor.
	 * \param key the path to the key, including the key. example: "Software\\Company\\SubKey\\MyValue"
	 * \param def the default value used when the key does not exist or a read error occured
	 * \param force set to TRUE if no cache should be used, i.e. always read and write directly from/to registry
	 * \param base a predefined base key like HKEY_LOCAL_MACHINE. see the SDK documentation for more information.
	 */
	CRegStdWORD(stdstring key, DWORD def = 0, BOOL force = FALSE, HKEY base = HKEY_CURRENT_USER);
	~CRegStdWORD(void);
	
	DWORD read();						///< reads the value from the registry
	void	write();					///< writes the value to the registry
		
	operator DWORD();
	CRegStdWORD& operator=(DWORD d);
	CRegStdWORD& operator+=(DWORD d) { return *this = *this + d;}
	CRegStdWORD& operator-=(DWORD d) { return *this = *this - d;}
	CRegStdWORD& operator*=(DWORD d) { return *this = *this * d;}
	CRegStdWORD& operator/=(DWORD d) { return *this = *this / d;}
	CRegStdWORD& operator%=(DWORD d) { return *this = *this % d;}
	CRegStdWORD& operator<<=(DWORD d) { return *this = *this << d;}
	CRegStdWORD& operator>>=(DWORD d) { return *this = *this >> d;}
	CRegStdWORD& operator&=(DWORD d) { return *this = *this & d;}
	CRegStdWORD& operator|=(DWORD d) { return *this = *this | d;}
	CRegStdWORD& operator^=(DWORD d) { return *this = *this ^ d;}
	
	
protected:

	DWORD	m_value;				///< the cached value of the registry
	DWORD	m_defaultvalue;			///< the default value to use
	BOOL	m_read;					///< indicates if the value has already been read from the registry
	BOOL	m_force;				///< indicates if no cache should be used, i.e. always read and write directly from registry
};