config.cc

#include <bits/stdc++.h>

using namespace std;

struct config_t {
    std::string variable;
    std::string value;
};

struct section_t {
    std::string name;
    std::vector<config_t> data;
};

class Config {
private:
    std::string filename;
    std::string trim(const std::string &str);

public:
    std::string delemeter = "=";
    std::vector<section_t> config;
    Config(std::string filename);
    int parse();
    
    std::string get(std::string section_name, std::string variable, std::string value = "None" );
    int         set(std::string section_name, std::string variable, std::string value);

    int save();
};

string
Config::
trim(const string& str)
{
    const auto string_begin = str.find_first_not_of(" \t");
    if (string_begin == string::npos)
        return "";
    
    const auto string_end = str.find_last_not_of(" \t");
    const auto string_range = string_end - string_begin + 1;
    return str.substr(string_begin,string_range);
}


Config::
Config(std::string filename)
{
    this->filename = filename;
}

int
Config::
parse()
{
    ifstream fptr;
    fptr.open(this->filename);
    if (fptr.good()) {

        string line;
        string curr_sec = "Main";

        while(getline(fptr, line)) {
            line = trim(line);

            if (line[0] == '[' && line[line.length() - 1] == ']') {

                curr_sec = line.substr(1,line.length() - 2);
    
                //std::cout << "Section: " << new_section.name << std::endl;
            } else {
                size_t pos = line.find(this->delemeter);
                if (pos == string::npos) {
                    continue;
                }

                string var = trim(line.substr(0,pos)),
                       val = trim(line.substr(pos + 1, line.length() )); 

                //std::cout << "Var: " << d.variable << " | Val: " << d.value << " | From: " << new_section.name << std::endl;
                this->set(curr_sec, var, val);
            }
                    
        }

    } else {
        return -1;
    }
    return 0;
}

string
Config::
get(std::string section_name,
    std::string variable, 
    std::string value)
{
    for(auto s : this->config) {
        if (s.name == section_name) {
            for (auto c: s.data) {
                if (c.variable == variable) {
                    return c.value;
                }
            }
        }
    }
    return value;
}



int
Config::
set(std::string section_name, 
    std::string variable, 
    std::string value)
{
    bool varfound = false,
         secfound = false;

    for(auto s = this->config.begin(); s != this->config.end(); s++) {
        if (s->name == section_name) {
            //std::cout << "found section name: " << s->name << std::endl;
            secfound = true;
            for(auto c = s->data.begin(); c != s->data.end(); c++) {
                if (c->variable == variable) {
                    varfound = true;
                    c->value = value;
                    return 0;
                }
            }
        }
    }

    if (!varfound) {

        if (!secfound) {
            section_t s;
            s.name = section_name;
            this->config.push_back(s);
            //std::cout << "new section added: " << s.name << std::endl;
        }

        for (auto s = this->config.begin(); s != this->config.end(); s++) {
            if (s->name == section_name) {

                //std::cout << "new variable added: " << variable << std::endl;
                config_t c;
                c.variable = variable;
                c.value = value;
                s->data.push_back(c);
            }
        }
    }

    return 0;
}

int
Config::
save()
{
    ofstream fptr;
    fptr.open(this->filename);
    if (fptr.good()) {
        for(auto s : this->config) {
            string heading = "\n[" + s.name + "]\n";
            fptr.write(heading.c_str(), heading.length());

            for (auto c: s.data) {
                string cstr = c.variable + this->delemeter +  c.value + "\n";
                fptr.write(cstr.c_str(), cstr.length());
            }
        }

        fptr.close();
    } else {
        return -1;
    }

    return 0;
}