Thread: [C++] Memory-writing functions

Snippets for writing bytes to specified memory address

WriteMemory - write an byte-array to memory-address.
WriteJump - both arguments are addresses, where to jump from and where to jump to.
WriteNop - address and how many to write.

 #ifndef MEMUTILS_H

#define MEMUTILS_H



BOOL WriteMemory( DWORD dwAddress, const void* cpvPatch, DWORD dwSize )

{

	DWORD dwProtect;



	if( VirtualProtect( (void*)dwAddress, dwSize, PAGE_READWRITE, &dwProtect ) ) //Unprotect the memory

		memcpy( (void*)dwAddress, cpvPatch, dwSize ); //Write our patch

	else

		return false; //Failed to unprotect, so return false..



	return VirtualProtect( (void*)dwAddress, dwSize, dwProtect, new DWORD ); //Reprotect the memory

}



BOOL WriteJump( DWORD From, DWORD To )

{

	if( To < From + 128 && To > From - 128 ) //Short jump

	{

		BYTE bpJump[2] = { 0xEB, ( To - From ) - 2 }; //Calculate opcode



		return WriteMemory( From, bpJump, 2 );

	}

	else //Far jump

	{

		BYTE bpJump[5] = { 0xE9, 0x00, 0x00, 0x00, 0x00 };

		*(DWORD*)&bpJump[1] = ( To - From ) - 5; //Calculate jump



		return WriteMemory( From, bpJump, 5 );

	}



	return false; //If we end up here, something went horribly wrong

}



BOOL WriteNop( DWORD dwAddress, DWORD dwAmount )

{

	BYTE bpNops[100]; //100 just incase I wanna do some gigantic NOPing 

	memset( bpNops, 0x90, 100 ); //Fill byte-array with NOPs



	return WriteMemory( dwAddress, bpNops, dwAmount );

}



#endif