Improved parameter parsing from config file

io.cpp

@@ -1,9 +1,12 @@
-#include <unordered_map>
+#include "phigrape.h"
 #include <string>
+#include <unordered_map>
+#include <stdexcept>
 #include <cstdio>
-#include <iostream>
 #include <fstream>
 
+using Dictionary = std::unordered_map<std::string,std::string>;
+
 std::string strip(const std::string str)
 {
     std::string str_new = str;
@@ -14,15 +17,11 @@ std::string strip(const std::string str)
     return str_new;
 }
 
-int main()
+Dictionary read_config_file(const std::string file_name)
 {
     std::unordered_map<std::string,std::string> dictionary;
-    std::string file_name = "phigrape.conf";
     std::ifstream file(file_name);
-    if (!file.good()) {
-        std::cout << "Not found!" << std::endl;
-        exit(1);
-    }
+    if (!file.good()) throw std::runtime_error("File not found.");
     std::string str;
     int line_number = 0;
     while (std::getline(file, str)) {
@@ -32,19 +31,93 @@ int main()
         str = strip(str);
         if (str.size() == 0) continue;
         pos = str.find_first_of("=");
-        if (pos == std::string::npos) {
-            std::cerr << "Error: expected a key-value pair in line " << line_number << " of file " << file_name << std::endl;
-            exit(1);
-        }
+        if (pos == std::string::npos) throw std::runtime_error("Error: expected a key-value pair in line " + std::to_string(line_number) + " of file " + file_name);
         std::string key = strip(str.substr(0, pos));
         pos = str.find_first_not_of(" \t", pos+1);
         std::string val = strip(str.substr(pos, str.size()));
         dictionary[key] = val;
     }
+    return dictionary;
+}
+
+template<typename T> T string_cast(const std::string str);
+
+template<> std::string string_cast(const std::string str)
+{
+    return str;
+}
+
+template<> double string_cast(const std::string str)
+{
+    size_t idx;
+    auto value = std::stod(str, &idx);
+    if (idx == str.size()) return value;
+    else throw std::runtime_error("Cannot convert \"" + str + "\" into a double");
+}
+
+template<> int string_cast(const std::string str)
+{
+    size_t idx;
+    auto value = std::stoi(str, &idx);
+    if (idx == str.size()) return value;
+    else throw std::runtime_error("Cannot convert \"" + str + "\" into an int");
+}
+
+template<> bool string_cast(const std::string str)
+{
+    if      ((str=="true")  || (str=="True")  || (str=="yes") || (str=="Yes") || (str=="1")) return true;
+    else if ((str=="false") || (str=="False") || (str=="no")  || (str=="No")  || (str=="0")) return false;
+    throw std::runtime_error("Cannot convert \"" + str + "\" into a bool");
+}
+
+
+// For mandatory parameters
+template<typename T>
+T get_parameter(Dictionary dictionary, std::string name)
+{
+    auto item = dictionary.find(name);
+    if (item==dictionary.end()) throw std::runtime_error("Mandatory parameter " + name + " must be defined");
+    else return string_cast<T>((*item).second);
+}
+
+// For optional parameters
+template<typename T>
+T get_parameter(Dictionary dictionary, std::string name, T default_value)
+{
+    auto item = dictionary.find(name);
+    if (item==dictionary.end()) return default_value;
+    else return string_cast<T>((*item).second);
+}
+
+int main()
+{
+    auto dictionary = read_config_file("phigrape.conf");
 
     for (auto key_value : dictionary) {
         auto key   = key_value.first;
         auto value = key_value.second;
         printf("dictionary[\"%s\"] = \"%s\"\n", key.c_str(), value.c_str());
     }
+
+
+    Parameters parameters;
+
+    // TODO check if dt_disk and dt_contr are powers of two
+    parameters.dt_bh = get_parameter<double>(dictionary, "eps");
+    parameters.t_end = get_parameter<double>(dictionary, "t_end");
+    parameters.dt_disk = get_parameter<double>(dictionary, "dt_disk");
+    parameters.dt_contr = get_parameter<double>(dictionary, "dt_contr");
+    parameters.dt_bh = get_parameter<double>(dictionary, "dt_bh", parameters.dt_contr);
+    parameters.eta = get_parameter<double>(dictionary, "eta");
+    parameters.input_file_name = get_parameter<std::string>(dictionary, "dt_bh", "data.con");
+    parameters.dt_min_warning = get_parameter<bool>(dictionary, "dt_min_warning", false);
+    parameters.live_smbh_count = get_parameter<int>(dictionary, "live_smbh_count", 0);
+    parameters.live_smbh_custom_eps = get_parameter<double>(dictionary, "live_smbh_custom_eps", -1);
+    parameters.live_smbh_output = get_parameter<bool>(dictionary, "live_smbh_output", false);
+    parameters.live_smbh_neighbor_output = get_parameter<bool>(dictionary, "live_smbh_neighbor_output", false);
+    parameters.live_smbh_neighbor_number = get_parameter<int>(dictionary, "live_smbh_neighbor_number", 10);
+    parameters.binary_smbh_pn = get_parameter<bool>(dictionary, "binary_smbh_pn", false);
+    parameters.binary_smbh_influence_sphere_output = get_parameter<bool>(dictionary, "binary_smbh_influence_sphere_output", false);
+    parameters.binary_smbh_influence_radius_factor = get_parameter<double>(dictionary, "binary_smbh_influence_radius_factor", 10.);
+
 }