utils.cpp

/*
	THIS FILE IS A PART OF GTA V SCRIPT HOOK SDK
				http://dev-c.com
			(C) Alexander Blade 2015
*/

#include "utils.h"
#include <windows.h>
#include <vector>

extern "C" IMAGE_DOS_HEADER __ImageBase; // MSVC specific, with other compilers use HMODULE from DllMain

std::string cachedModulePath;

std::string GetCurrentModulePath()
{
	if (cachedModulePath.empty())
	{
		// get module path
		char modPath[MAX_PATH];
		memset(modPath, 0, sizeof(modPath));
		GetModuleFileNameA((HMODULE)&__ImageBase, modPath, sizeof(modPath));
		for (size_t i = strlen(modPath); i > 0; i--)
		{
			if (modPath[i - 1] == '\\')
			{
				modPath[i] = 0;
				break;
			}
		}
		cachedModulePath = modPath;
	}
	return cachedModulePath;
}

std::uint8_t * PatternScan(void* module, const char* signature)
{
    static auto pattern_to_byte = [](const char* pattern) {
        auto bytes = std::vector<int>{};
        auto start = const_cast<char*>(pattern);
        auto end = const_cast<char*>(pattern) + strlen(pattern);

        for (auto current = start; current < end; ++current) {
            if (*current == '?') {
                ++current;
                if (*current == '?')
                    ++current;
                bytes.push_back(-1);
            }
            else {
                bytes.push_back(strtoul(current, &current, 16));
            }
        }
        return bytes;
    };

    auto dosHeader = (PIMAGE_DOS_HEADER)module;
    auto ntHeaders = (PIMAGE_NT_HEADERS)((std::uint8_t*)module + dosHeader->e_lfanew);

    auto sizeOfImage = ntHeaders->OptionalHeader.SizeOfImage;
    auto patternBytes = pattern_to_byte(signature);
    auto scanBytes = reinterpret_cast<std::uint8_t*>(module);

    auto s = patternBytes.size();
    auto d = patternBytes.data();

    for (auto i = 0ul; i < sizeOfImage - s; ++i) {
        bool found = true;
        for (auto j = 0ul; j < s; ++j) {
            if (scanBytes[i + j] != d[j] && d[j] != -1) {
                found = false;
                break;
            }
        }
        if (found) {
            return &scanBytes[i];
        }
    }
    return nullptr;
}