VMTHookManager

#pragma once
#include <Windows.h>
class CVMTHookManager
{
public:
	CVMTHookManager( )
	{
		memset( this, 0, sizeof( CVMTHookManager ) );
	}

	CVMTHookManager( PDWORD* ppdwClassBase )
	{
		bInitialize( ppdwClassBase );
	}

	~CVMTHookManager( )
	{
		UnHook();
	}
	bool bInitialize( PDWORD* ppdwClassBase )
	{
		m_ppdwClassBase = ppdwClassBase;
		m_pdwOldVMT = *ppdwClassBase;
		m_dwVMTSize = dwGetVMTCount( *ppdwClassBase );
		m_pdwNewVMT = new DWORD[ m_dwVMTSize ];
		memcpy( m_pdwNewVMT, m_pdwOldVMT, sizeof( DWORD ) * m_dwVMTSize );
		*ppdwClassBase = m_pdwNewVMT;
		return true;
	}
	bool bInitialize( PDWORD** pppdwClassBase ) // fix for pp
	{
		return bInitialize( *pppdwClassBase );
	}

	void UnHook( )
	{
		if ( m_ppdwClassBase )
		{
			*m_ppdwClassBase = m_pdwOldVMT;
		}
	}

	void ReHook( )
	{
		if ( m_ppdwClassBase )
		{
			*m_ppdwClassBase = m_pdwNewVMT;
		}
	}

	int iGetFuncCount( )
	{
		return ( int ) m_dwVMTSize;
	}

	DWORD dwGetMethodAddress( int Index )
	{
		if ( Index >= 0 && Index <= ( int )m_dwVMTSize && m_pdwOldVMT != NULL )
		{
			return m_pdwOldVMT[ Index ];
		}
		return NULL;
	}

	PDWORD pdwGetOldVMT( )
	{
		return m_pdwOldVMT;
	}

	DWORD dwHookMethod( DWORD dwNewFunc, unsigned int iIndex )
	{
		if ( m_pdwNewVMT && m_pdwOldVMT && iIndex <= m_dwVMTSize && iIndex >= 0 )
		{
			m_pdwNewVMT[ iIndex ] = dwNewFunc;
			return m_pdwOldVMT[ iIndex ];
		}

		return NULL;
	}

private:
	DWORD dwGetVMTCount( PDWORD pdwVMT )
	{
		DWORD dwIndex = 0;

		for ( dwIndex = 0; pdwVMT[ dwIndex ]; dwIndex++ )
		{
			if ( IsBadCodePtr( ( FARPROC ) pdwVMT[ dwIndex ] ) )
			{
				break;
			}
		}
		return dwIndex;
	}
	PDWORD*	m_ppdwClassBase;
	PDWORD	m_pdwNewVMT, m_pdwOldVMT;
	DWORD	m_dwVMTSize;
};