Optimized Enter/Leave Logger

/*
Header file of Log.h.
This header is used in all functions to provide enter and leave log.

Usage: Create a local object of LogEnterLeave in your function.
       LogEnterLeave constructor will take the instruction pointer and write to
       log file with some additional information.

       LogEnterLeave destructor will take the instruction pointer and write to
       log file with some additional information.

       These informations( instruction pointers ) can be parsed at a later time by
       LogParser application with the help of pdb files. LogParser will recreate the
       actual log files from the encrypted form of enter and        leave log with the additional informations.

       Additional Information collected by this logger:
       1. Thread ID.
       2. Current System time.

Author Santhosh G.
Send Comments @ santhosh4g@gmail.com
Or http://www.codeproject.com/Members/santhosh4gCode
 */
#ifndef _LOG_HEADER_H_
#define _LOG_HEADER_H_
typedef struct
{
    int  nFunctionAddress;
    DWORD dwThreadID;
    DWORD   nTickCount;
    int bEnterFunction;
}LOG_DETAILS_t;

class LogEnterLeave
{

public:
    LogEnterLeave()
    {
        int nEBPContents;
        __asm mov nEBPContents, EBP;
        int* ptrAddress = (int*)nEBPContents;
        const int nReturnIP = *( ++ptrAddress ); // Here nReturnIP holds the address of caller function.
        WriteToFile( nReturnIP, true ); // Here Enter flag is true
    }
    ~LogEnterLeave()
    {
        int nEBPContents;
        __asm mov nEBPContents, EBP;
        int* ptrAddress = (int*)nEBPContents;
        const int nReturnIP = *( ++ptrAddress ); // Here nReturnIP holds the address of caller function.
        WriteToFile( nReturnIP, false ); // Here Enter flag is false
    }

private:

    void WriteToFile( const int nAddress_i, const bool bEnter_i )
    {
        // Get Thread ID from TIB.
        DWORD dwThreadID;
        __asm {
            mov EAX, FS:[0x24]
            mov [dwThreadID], EAX
        }

        const int nTickCount = GetTickCount();
        const LOG_DETAILS_t stLogDetails = { nAddress_i, dwThreadID, nTickCount, bEnter_i };

        FILE* pFile = fopen( "LogDetails.dat", "ab" );
        fwrite( &stLogDetails, sizeof( stLogDetails ), 1, pFile );
        fclose( pFile );
    }
};
#endif// _LOG_HEADER_H_