scan.cpp

#include "scan.hpp"
#include "print.hpp"

#define IS_IN_RANGE( value, max, min ) ( value >= max && value <= min )
#define GET_BITS( value ) ( IS_IN_RANGE( value, '0', '9' ) ? ( value - '0' ) : ( ( value & ( ~0x20 ) ) - 'A' + 0xA ) )
#define GET_BYTE( value ) ( GET_BITS( value[0] ) << 4 | GET_BITS( value[1] ) )

namespace Horizon::Memory
{

std::uintptr_t Scan( const std::string& image_name, const std::string& signature )
{
	auto image = GetModuleHandleA( image_name.c_str() );

	if( !image )
	{
#ifdef DEBUG
		Win32::Error( "GetModuleHandleA failed (L3D451R7::Memory::%s)", __FUNCTION__ );
#endif // DEBUG
		return 0u;
	}

	auto image_base = ( std::uintptr_t )( image );
	auto image_dos_hdr = ( IMAGE_DOS_HEADER* )( image_base );

	if( image_dos_hdr->e_magic != IMAGE_DOS_SIGNATURE )
	{
#ifdef DEBUG
		Win32::Error( "IMAGE_DOS_HEADER::e_magic is invalid (L3D451R7::Memory::%s)", __FUNCTION__ );
#endif // DEBUG
		return 0u;
	}

	auto image_nt_hdrs = ( IMAGE_NT_HEADERS* )( image_base + image_dos_hdr->e_lfanew );

	if( image_nt_hdrs->Signature != IMAGE_NT_SIGNATURE )
	{
#ifdef DEBUG
		Win32::Error( "IMAGE_NT_HEADERS::Signature is invalid (L3D451R7::Memory::%s)", __FUNCTION__ );
#endif // DEBUG
		return 0u;
	}

	auto scan_begin = ( std::uint8_t* )( image_base );
	auto scan_end = ( std::uint8_t* )( image_base + image_nt_hdrs->OptionalHeader.SizeOfImage );

	std::uint8_t* scan_result = nullptr;
	std::uint8_t* scan_data = ( std::uint8_t* )( signature.c_str() );

	for( auto current = scan_begin; current < scan_end; current++ )
	{
		if( *( std::uint8_t* )scan_data == '\?' || *current == GET_BYTE( scan_data ) )
		{
			if( !scan_result )
				scan_result = current;

			if( !scan_data[2] )
				return ( std::uintptr_t )( scan_result );

			scan_data += ( *( std::uint16_t* )scan_data == '\?\?' || *( std::uint8_t* )scan_data != '\?' ) ? 3 : 2;

			if( !*scan_data )
				return ( std::uintptr_t )( scan_result );
		}
		else if( scan_result )
		{
			current = scan_result;
			scan_data = ( std::uint8_t* )( signature.c_str() );
			scan_result = nullptr;
		}
	}

#ifdef DEBUG
	Win32::Warning( "Signature '%s' in module '%s' not found (L3D451R7::Memory::%s)", signature.c_str(), image_name.c_str(), __FUNCTION__ );
#endif // DEBUG

	return 0u;
}

DWORD follow_rel32(DWORD addr, size_t offset)
{
	if (!addr)
		return NULL;

	auto offsetAddr = addr + offset;
	auto relative = *(uint32_t*)(offsetAddr);
	if (!relative)
		return NULL;

	return (DWORD)(offsetAddr + relative + sizeof(uint32_t));
}

}