Simple Program To Count Lines of Code Of Another Program

loc_counter.cpp

/*
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include <iostream>
#include <filesystem>
#include <string>
#include <vector>
#include <fstream>
#include <algorithm>

class extension_checker{
public:
    extension_checker(int argc, char *argv[]);
    bool matches(const std::string &name) const noexcept;

private:
    std::vector<std::string> m_extensions;
};

bool ends_with(const std::string &str, const std::string &suffix);
unsigned long count_lines_of_code(const std::filesystem::path &file);

int main(int argc, char *argv[]) {
    if(argc < 3){
        std::cerr << "Usage: " << argv[0] << " <directory> <file-extension-1> [file-extension-2] [file-extension-3] ..." << std::endl;
        return -1;
    }

    extension_checker extensionchecker(argc-2, argv+2);
    unsigned long loccount = 0;
    std::filesystem::path directory(argv[1]);

    for(auto &file : std::filesystem::recursive_directory_iterator(directory)){
        if(std::filesystem::is_regular_file(file)){
            const auto &fileName = file.path().filename();
            std::cout << file << "\n";
            if(extensionchecker.matches(fileName)){
                unsigned long currentcount = count_lines_of_code(file);
                std::cout << "Found " << currentcount << " lines of code in " << file << ".\n";
                loccount += currentcount;
            }else{
                std::cout << "Skipping " << file << " because it does not match any of the provided extensions.\n";
            }
        }
    }

    std::cout << "Counted " << loccount << " total lines of code." << std::endl;

    return 0;
}

extension_checker::extension_checker(int argc, char *argv[]) {
    m_extensions.reserve(argc);
    for(unsigned i=0;i<argc;++i){
        m_extensions.emplace_back(argv[i]);
    }
}

bool extension_checker::matches(const std::string &name) const noexcept {
    for(auto &extension : m_extensions){
        if(ends_with(name, extension)){
            return true;
        }
    }
    return false;
}

bool ends_with(const std::string &str, const std::string &suffix){
    if(str.length() < suffix.length()){
        return false;
    }

    auto strit = str.rbegin();
    for(auto it=suffix.rbegin();it!=suffix.rend();++it){
        if(*it != *(strit++)){
            return false;
        }
    }

    return true;
}

unsigned long count_lines_of_code(const std::filesystem::path &file){
    //reading in binary mode because we want to count the number of \n characters, and text mode does annoying formatting that makes this much more difficult
    std::ifstream fin;
    fin.exceptions(std::ios::badbit | std::ios::failbit);
    fin.open(file, std::ios::binary | std::ios::ate);
    std::vector<char> data(fin.tellg(), 0);
    fin.seekg(0);
    fin.read(data.data(), data.size());
    return std::count(data.begin(), data.end(), '\n');
}