.. _program_listing_file_lib_Config.cpp:

Program Listing for File Config.cpp
===================================

|exhale_lsh| :ref:`Return to documentation for file <file_lib_Config.cpp>` (``lib/Config.cpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #include "Config.hpp"
   #include <nlohmann/json.hpp>
   #include <iostream>
   #include <fstream>
   #include <unistd.h>
   #include <limits.h>
   #include <string.h>
   
   using namespace std;
   
   Config::Config() {
     read_config(get_config_file_path());
   }
   
   // get an int val
   int Config::get_int(string field, int fallback) {
     return config.contains(field) ? (int)config[field] : fallback;
   }
   
   // get a string val
   string Config::get_string(string field, string fallback) {
     return config.contains(field) ? (string)config[field] : fallback;
   }
   
   // get a double val
   double Config::get_double(string field, double fallback) {
     return config.contains(field) ? (double)config[field] : fallback;
   }
   
   // get a boolean val
   bool Config::get_bool(string field, bool fallback) {
     return config.contains(field) ? (bool)config[field] : fallback;
   }
   
   // Determine config filename for our runtime environment
   string Config::get_config_file_path() {
   
     // find the full path of our current working directory
     char cwd[PATH_MAX + 1];
     getcwd(cwd, sizeof(cwd));
   
     char* dirname = strrchr(cwd, '/');
     
     char filename[PATH_MAX + 100];  
   
     // find the path to the config file based on OS
     if(strcmp(dirname,"/delphi") == 0) {
       // Docker 
       sprintf(filename,"%s/data/%s", cwd, FILENAME.c_str());
     } else if(strcmp(dirname,"/build") == 0) {
       // Anything else
       sprintf(filename,"%s/../data/%s", cwd, FILENAME.c_str());
     }
   
     // check that the file actually exists
     if( access(filename, F_OK ) == 0 ) {
       // file exists
       return string(filename);
     } 
   
     // unrecognized directory for delphi execution
     cerr << "Could not locate config file 'config.json'.  "
     << "Delphi should be run in the 'delphi/build' directory "
     << "on a Linux or MAC operating system, or in the 'delphi' directory "
     << "in a Docker container."
     << endl;
   
     exit(1);
   }
   
   // Return a JSON struct read from the config file
   void Config::read_config(string filename) {
     ifstream file;
     file.open(filename);
     string jsonString;
     string line;
     if ( file.is_open() ) {
       while ( file ) { 
         getline (file, line);
         jsonString += line;
       }
       file.close();
       config = json::parse(jsonString);
     }
     else {
       cerr << "Couldn't open config file at '" << filename << "'" << endl;
       exit(1);
     }
   }