config.hpp

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/*************************************************************************
 * Copyright (C) 2011 by Saleh Dindar and the Swarm-NG Development Team  *
 *                                                                       *
 * 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.        *
 *                                                                       *
 * 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, write to the                         *
 * Free Software Foundation, Inc.,                                       *
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ************************************************************************/

#pragma once
#include <stdexcept>

namespace swarm {


struct key_not_found: std::runtime_error {
        key_not_found(const std::string &key): std::runtime_error("Key not found: \"" + key + "\"") {}
};

class config : public std::map<std::string, std::string> {
public:

        config(){}

        template< class T >
        config(const T& key_value_pairs){
                initialize(key_value_pairs, sizeof(T)/sizeof(char*[2]));
        }



        void initialize(const char* const key_value_pairs[][2], const int n);

        static config load(const std::string &fn,config cfg = config() );

        static bool valid_value(const std::string& v, std::string) {
                return v.size() > 0;
        }
        static std::string parse(const std::string& v, std::string) {
                return v;
        }
        
        static bool valid_value(const std::string& v, double) {
                double d = 0;
                int r = sscanf(v.c_str(),"%lg", &d);
                return r == 1;
        }
        static double parse(const std::string& v, double) {
                double d = 0;
                int r = sscanf(v.c_str(),"%lg", &d);
                return d;
        }

        static bool valid_value(const std::string& v, float) {
                float d = 0;
                int r = sscanf(v.c_str(),"%g", &d);
                return r == 1;
        }
        static float parse(const std::string& v, float) {
                float d = 0;
                int r = sscanf(v.c_str(),"%g", &d);
                return d;
        }

        static bool valid_value(const std::string& v, int) {
                int d = 0;
                int r = sscanf(v.c_str(),"%i", &d);
                return r == 1;
        }
        static int parse(const std::string& v, int) {
                int d = 0;
                int r = sscanf(v.c_str(),"%i", &d);
                return d;
        }

        bool valid(const std::string& key)const{
                return count(key) && (at(key).size() > 0);
        }

        template<typename T> bool valid(const std::string& key , T t )const{
                return valid(key) && valid_value(at(key),t);
        }

        template<typename T> T optional(const std::string& key , const T& default_value)const{
                if( count(key) ) {
                        std::string value = at(key);
                        return valid_value(value,T()) ? parse(value,T()) : default_value;
                } else
                        return default_value;
        }

        template<typename T> T require(const std::string& key, const T&  = T() )const{
                if( count(key) && valid_value(at(key),T()) )
                        return parse(at(key),T());
                else
                        throw key_not_found(key);
        }
};

}