refactor: Patch logic refactored using C++20

fix: Resolve issue with non-functional pause functionality
fix: Throw error when .bak file already exists
fix: Backup when file patched

Signed-off-by: Mai Ooizumi <mai@imomoe.moe>

Author: Mai-Ooizumi

VScriptAutoPatcher/VScriptAutoPatcher.cpp

@@ -1,40 +1,83 @@
 #include <iostream>
-#include <Windows.h>
 #include <vector>
 #include <cstdint>
 #include <filesystem>
+#include <fstream>
+
+#ifdef _WIN32
+#include <Windows.h>
+#include <conio.h>
 
-bool readFile(const std::string& filename, std::vector<uint8_t>& buffer)
+static std::string SelectPEFile()
 {
-	HANDLE fileHandle = CreateFileA(
-		filename.c_str(),
-		GENERIC_READ,
-		FILE_SHARE_READ,
-		NULL,
-		OPEN_EXISTING,
-		FILE_ATTRIBUTE_NORMAL,
-		NULL
-	);
-
-	if (fileHandle == INVALID_HANDLE_VALUE)
+	TCHAR szBuffer[MAX_PATH] = { 0 };
+	OPENFILENAME file = { 0 };
+
+	ZeroMemory(&file, sizeof(file));
+
+	file.hwndOwner = NULL;
+	file.lStructSize = sizeof(file);
+	file.lpstrFilter = L"vscript.dll(vscript.dll)\0vscript.dll\0所有文件(*.*)\0*.*\0\0";
+	file.lpstrInitialDir = L"";
+	file.lpstrFile = szBuffer;
+	file.nMaxFile = sizeof(szBuffer) / sizeof(*szBuffer);
+	file.nFilterIndex = 0;
+	file.Flags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
+
+	if (GetOpenFileName(&file))
 	{
-		std::cerr << "[ERROR] " << "Failed to create handle to: " << filename << std::endl;
-		//std::cout << "[REMINDER] " << "Make sure the executable is in same folder with: " << filename << std::endl;
-		return false;
+		int size = WideCharToMultiByte(CP_ACP, 0, file.lpstrFile, -1, NULL, 0, NULL, NULL);
+		if (size == 0)
+		{
+			return std::string();
+		}
+		std::string result(size - 1, 0);
+		WideCharToMultiByte(CP_ACP, 0, file.lpstrFile, -1, &result[0], size, NULL, NULL);
+		return result;
 	}
+	else
+	{
+		return std::string();
+	}
+}
+
+static void Pause()
+{
+	std::cout << "Press any key to continue..." << std::flush;
+	(void)_getch();
+}
 
-	DWORD fileSize = GetFileSize(fileHandle, NULL);
-	buffer.resize(fileSize);
+#else
 
-	DWORD bytesRead = 0;
-	ReadFile(fileHandle, buffer.data(), fileSize, &bytesRead, NULL);
+static void Pause()
+{
 
-	CloseHandle(fileHandle);
+}
 
+#endif // _WIN32
+
+static bool readFile(const std::string & fileName, std::vector<uint8_t> & buffer)
+{
+	std::ifstream file(fileName, std::ios::binary);
+
+	if (!file.is_open())
+	{
+		std::cerr << "[ERROR] " << "Failed to open file: " << fileName << std::endl;
+		return false;
+	}
+
+	file.seekg(0, std::ios::end);
+	std::streamsize fileSize = file.tellg();
+	file.seekg(0, std::ios::beg);
+
+	buffer.resize(static_cast<size_t>(fileSize));
+	file.read(reinterpret_cast<char *>(buffer.data()), fileSize);
+
+	file.close();
 	return true;
 }
 
-std::vector<size_t> findHexArray(std::vector<uint8_t>& buffer, const std::vector<uint8_t>& hexArray)
+static std::vector<size_t> findHexArray(const std::vector<uint8_t> & buffer, const std::vector<uint8_t> & hexArray)
 {
 	std::vector<size_t> positions;
 
@@ -43,16 +86,11 @@ std::vector<size_t> findHexArray(std::vector<uint8_t>& buffer, const std::vector
 
 	for (size_t i = 0; i <= bufferSize - arraySize; ++i)
 	{
-		bool found = true;
-
-		for (size_t j = 0; j < arraySize; ++j) {
-			if (buffer[i + j] != hexArray[j] && hexArray[j] != 0x2A) {
-				found = false;
-				break;
-			}
-		}
-
-		if (found)
+		if (std::ranges::equal(buffer.begin() + i, buffer.begin() + i + arraySize, hexArray.begin(), hexArray.end(),
+							   [](uint8_t a, uint8_t b)
+		{
+			return a == b || b == 0x2A;
+		}))
 		{
 			std::cout << "[INFO] " << "Found position at buffer index: " << i << std::endl;
 			positions.push_back(i);
@@ -62,37 +100,27 @@ std::vector<size_t> findHexArray(std::vector<uint8_t>& buffer, const std::vector
 	return positions;
 }
 
-bool writeFile(const std::string& filename, const std::vector<uint8_t>& buffer)
+static bool writeFile(const std::string & fileName, const std::vector<uint8_t> & buffer)
 {
-	HANDLE fileHandle = CreateFileA(
-		filename.c_str(),
-		GENERIC_WRITE,
-		0,
-		NULL,
-		CREATE_ALWAYS,
-		FILE_ATTRIBUTE_NORMAL,
-		NULL
-	);
-
-	if (fileHandle == INVALID_HANDLE_VALUE)
-	{
-		std::cerr << "[ERROR] " << "Failed to create handle to: " << filename << std::endl;
-		//std::cout << "[REMINDER] " << "Make sure the executable is in same folder with: " << filename << std::endl;
+	std::ofstream file(fileName, std::ios::binary);
 
+	if (!file.is_open())
+	{
+		std::cerr << "[ERROR] " << "Failed to open file: " << fileName << std::endl;
 		return false;
 	}
 
-	DWORD bytesWritten = 0;
-	WriteFile(fileHandle, buffer.data(), buffer.size(), &bytesWritten, NULL);
+	file.write(reinterpret_cast<const char *>(buffer.data()), buffer.size());
 
-	CloseHandle(fileHandle);
+	file.close();
 
-	return (bytesWritten == buffer.size());
+	return true;
 }
 
-void PatchFile(std::string fileName, std::vector<uint8_t> originalArray, std::vector<uint8_t> replacedArray)
+static void patchFile(const std::string & fileName, const std::vector<uint8_t> & originalArray, const std::vector<uint8_t> & replacedArray)
 {
 	std::vector<uint8_t> buffer;
+
 	if (!readFile(fileName, buffer))
 	{
 		return;
@@ -102,19 +130,19 @@ void PatchFile(std::string fileName, std::vector<uint8_t> originalArray, std::ve
 
 	if (positions.empty())
 	{
-		std::cout << "[ERROR] " << fileName << " is already patched" << std::endl;
+		std::cerr << "[ERROR] " << fileName << " is already patched" << std::endl;
 		return;
 	}
 
+	if (std::filesystem::exists(fileName + ".bak"))
+	{
+		std::filesystem::remove(fileName + ".bak");
+	}
+	std::filesystem::copy(fileName, fileName + ".bak");
+
 	for (size_t pos : positions)
 	{
-		for (size_t i = 0; i < replacedArray.size(); ++i)
-		{
-			if (replacedArray[i] != 0x2A)
-			{
-				buffer[pos + i] = replacedArray[i];
-			}
-		}
+		std::ranges::copy(replacedArray.begin(), replacedArray.end(), buffer.begin() + pos);
 	}
 
 	if (!writeFile(fileName, buffer))
@@ -125,48 +153,6 @@ void PatchFile(std::string fileName, std::vector<uint8_t> originalArray, std::ve
 	std::cout << "[SUCCESS] " << fileName << " has been patched." << std::endl;
 }
 
-static std::string SelectPEFile()
-{
-	TCHAR szBuffer[MAX_PATH] = { 0 };
-	OPENFILENAME file = { 0 };
-
-	ZeroMemory(&file, sizeof(file));
-
-	file.hwndOwner = NULL;
-	file.lStructSize = sizeof(file);
-	file.lpstrFilter = L"vscript.dll(vscript.dll)\0vscript.dll\0所有文件(*.*)\0*.*\0\0";
-	file.lpstrInitialDir = L"";
-	file.lpstrFile = szBuffer;
-	file.nMaxFile = sizeof(szBuffer) / sizeof(*szBuffer);
-	file.nFilterIndex = 0;
-	file.Flags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
-
-	if (GetOpenFileName(&file))
-	{
-		int size = WideCharToMultiByte(CP_ACP, 0, file.lpstrFile, -1, NULL, 0, NULL, NULL);
-		if (size == 0)
-		{
-			return std::string();
-		}
-		std::string result(size - 1, 0);
-		WideCharToMultiByte(CP_ACP, 0, file.lpstrFile, -1, &result[0], size, NULL, NULL);
-		return result;
-	}
-	else
-	{
-		return std::string();
-	}
-}
-
-static void Pause()
-{
-	std::cout << "Press any key to continue..." << std::flush;
-	HANDLE h = GetStdHandle(STD_INPUT_HANDLE);
-	FlushConsoleInputBuffer(h);
-	WaitForSingleObject(h, INFINITE);
-	FlushConsoleInputBuffer(h);
-}
-
 int main(int argc, const char * const * argv)
 {
 	std::string filePath;
@@ -198,23 +184,21 @@ int main(int argc, const char * const * argv)
 		{
 			filePath = "./bin/win64/vscript.dll";
 		}
-
+#ifdef _WIN32
 		if (!std::filesystem::exists(filePath))
 		{
 			filePath = SelectPEFile();
 		}
+#endif // _WIN32
 		if (std::filesystem::exists(filePath))
 		{
-			std::filesystem::copy(filePath, filePath + ".bak");
-
-			PatchFile(filePath, { 0xBE, 0x01, 0x2A, 0x2A, 0x2A, 0x2B, 0xD6, 0x74, 0x2A, 0x3B, 0xD6 }, { 0xBE, 0x02 });
+			patchFile(filePath, { 0xBE, 0x01, 0x2A, 0x2A, 0x2A, 0x2B, 0xD6, 0x74, 0x2A, 0x3B, 0xD6 }, { 0xBE, 0x02 });
 		}
 		else
 		{
 			std::cerr << "File doesn't exist" << std::endl;
 			return 2;
 		}
-
 	}
 	catch (const std::exception & e)
 	{