Pattern scan and replace [C++]

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

// Function to read the content of the file into a vector
std::vector<uint8_t> readBinaryFile(const std::string& filename) {
    std::ifstream file(filename, std::ios::binary | std::ios::ate);
    if (!file.is_open()) {
        throw std::runtime_error("Failed to open file");
    }

    std::streamsize fileSize = file.tellg();
    file.seekg(0, std::ios::beg);

    std::vector<uint8_t> buffer(fileSize);
    if (!file.read(reinterpret_cast<char*>(buffer.data()), fileSize)) {
        throw std::runtime_error("Failed to read file");
    }

    return buffer;
}

// Function to modify the bytes in the vector using a mask
void modifyBytes(std::vector<uint8_t>& data, const std::vector<uint8_t>& pattern, const std::vector<uint8_t>& mask, const std::vector<uint8_t>& replacement) {
    if (pattern.size() != mask.size() || pattern.size() != replacement.size()) {
        throw std::runtime_error("Pattern, mask, and replacement must have the same size");
    }

    auto it = std::search(data.begin(), data.end(), pattern.begin(), pattern.end());

    while (it != data.end()) {
        auto startPos = std::distance(data.begin(), it);

        // Check if the pattern matches using the mask
        bool patternMatches = true;
        for (size_t i = 0; i < pattern.size(); ++i) {
            if ((data[startPos + i] & mask[i]) != pattern[i]) {
                patternMatches = false;
                break;
            }
        }

        // If the pattern matches, replace the bytes
        if (patternMatches) {
            std::copy(replacement.begin(), replacement.end(), data.begin() + startPos);
        }

        it = std::search(it + 1, data.end(), pattern.begin(), pattern.end());
    }
}

int main() {
    try {
        std::string filename = "example.exe";
        std::vector<uint8_t> fileData = readBinaryFile(filename);

        // Define the pattern, mask, and replacement
        std::vector<uint8_t> pattern = {0x12, 0x34, 0x56};
        std::vector<uint8_t> mask = {0xFF, 0xFF, 0xFF}; // Use 0xFF for exact match, 0x00 to ignore the byte
        std::vector<uint8_t> replacement = {0xAB, 0xCD, 0xEF};

        modifyBytes(fileData, pattern, mask, replacement);

        // Write the modified data back to the file (optional)
        std::ofstream outputFile(filename, std::ios::binary);
        if (!outputFile.write(reinterpret_cast<const char*>(fileData.data()), fileData.size())) {
            throw std::runtime_error("Failed to write to file");
        }

        std::cout << "Modification successful.\n";
    }
    catch (const std::exception& ex) {
        std::cerr << "Error: " << ex.what() << std::endl;
        return 1;
    }

    return 0;
}