passwdgen/passwdgen.cpp

//
//  passwdgen.cpp
//  Created by Greg Gauthier on 2020.10.22.
//

#include <iostream>
#include <random>


std::string random_string(std::size_t length, bool punc) {
    std::string CHARACTERS;
    std::string ALPHANUM = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    const std::string SPECIALS = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";

    if (punc) {
        CHARACTERS = ALPHANUM.append(SPECIALS);
    } else {
        CHARACTERS = ALPHANUM;
    }

    std::random_device random_device;
    std::mt19937 generator(random_device());
    std::uniform_int_distribution<> distribution(0, static_cast<int>(CHARACTERS.size() - 1));

    std::string random_string;
    for (std::size_t i = 0; i < length; ++i) {
        random_string += CHARACTERS[distribution(generator)];
    }
    return random_string;
}

void show_usage(const std::string& name) {
    std::cerr << "Usage: " << name << " [OPTIONS] " << std::endl
              << "Options:" << std::endl
              << "\t-h, --help          \t\tShow this help message" << std::endl
              << "\t-l, --length [n]    \t\tThe length of the password (default: 32)" << std::endl
              << "\t-p, --punctuation \t\tToggle special characters (default: false)"
              << std::endl;
}

int main(int argc, char *argv[]) {
    int passwordLength = 0;
    bool punc = false;

    if (argc < 1) {
        std::cout << random_string(32, false) << std::endl;
        return 0;
    }
    for (int i = 1; i < argc; ++i) {
        std::string arg = argv[i];
        if ((arg == "-h") || (arg == "--help")) {
            show_usage(argv[0]);
            return 0;
        }
        if (arg == "-p") {
            punc = true;
        } else if ((arg == "-l") || (arg == "--length")) {
            if (not argv[i +1]) {
                std::cerr << "Specify a password length" << std::endl;
                return 1;
            }
            std::string passwordLengthStr = argv[i + 1];
            try {
                passwordLength = std::stoi(passwordLengthStr);
            } catch ([[maybe_unused]] const std::invalid_argument& e){
                std::cerr << "Length must be a valid integer" << std::endl;
                return 1;
            }
        }
    }

    if (passwordLength == 0) {
        passwordLength = 32;
    }
    std::string password = random_string(passwordLength, punc);
    std::cout << password << std::endl;
    return 0;
}