ail/configuration.hpp

   1 #pragma once
   2
   3 #include <string>
   4 #include <vector>
   5 #include <map>
   6 #include <iostream>
   7
   8 #include <ail/file.hpp>
   9 #include <ail/string.hpp>
  10 #include <ail/exception.hpp>
  11
  12 namespace ail
  13 {
  14         class configuration
  15         {
  16
  17         public:
  18
  19                 configuration();
  20                 configuration(std::string const & file_name);
  21
  22                 bool load(std::string const & new_file_name);
  23
  24                 std::string string(std::string const & variable_name);
  25                 std::string string(std::string const & variable_name, std::string const & default_value);
  26
  27                 template <typename number_type>
  28                         bool read_number(std::string const & variable_name, number_type & output)
  29                 {
  30                         std::map<std::string, std::string>::iterator search = values.find(variable_name);
  31                         if(search == values.end())
  32                         {
  33                                 return false;
  34                         }
  35
  36                         try
  37                         {
  38                                 output = ail::string_to_number<number_type>(search->second);
  39                         }
  40                         catch(std::exception const &)
  41                         {
  42                                 std::cout << "Unable to find string value \"" << variable_name << "\" in \"" << file_name << "\"" << std::endl;
  43                                 throw exception("Failed to parse numeric value for a variable");
  44                         }
  45
  46                         return true;
  47                 }
  48
  49                 template <typename number_type>
  50                         number_type number(std::string const & variable_name)
  51                 {
  52                         number_type output;
  53                         bool success = read_number<number_type>(variable_name, output);
  54                         if(success == false)
  55                         {
  56                                 std::cout << "Unable to find string value \"" << variable_name << "\" in \"" << file_name << "\"" << std::endl;
  57                                 throw exception("Missing value for a required variable");
  58                         }
  59                         return output;
  60                 }
  61
  62                 template <typename number_type>
  63                         number_type number(std::string const & variable_name, number_type default_value)
  64                 {
  65                         number_type output;
  66                         bool success;
  67
  68                         try
  69                         {
  70                                 success = read_number<number_type>(variable_name, output);
  71                         }
  72                         catch(std::exception const &)
  73                         {
  74                                 return default_value;
  75                         }
  76
  77                         if(success == false)
  78                         {
  79                                 return default_value;
  80                         }
  81
  82                         return output;
  83                 }
  84
  85         private:
  86
  87                 bool read_string(std::string const & variable_name, std::string & output);
  88
  89                 std::string file_name;
  90                 std::map<std::string, std::string> values;
  91         };
  92 }