[config] Add wrapper around key-value map

src/config.cc

@@ -56,9 +56,8 @@ config::config(std::string filename) {
 }
 
 void config::print() const {
-  for (std::map<std::string, std::string>::const_iterator it = vmap.begin(); it != vmap.end();
-       it++) {
-    LOG(INFO) << "key " << it->first << " value " << it->second;
+  for (const auto& it : vmap) {
+    LOG(INFO) << "key " << it.first << " value " << it.second;
   }
 }
 

src/config.h

@@ -11,6 +11,26 @@
 #include "processor.h"
 
 class config {
+  class ConfigMap {
+    std::map<std::string, std::string> _configMap;
+
+   public:
+    std::string &operator[](std::string &key) { return _configMap[key]; }
+    std::string at(std::string key) const {
+      try {
+        return _configMap.at(key);
+      } catch (std::exception &e) {
+        std::cout << "Error fetching value for key `" << key << "`!" << std::endl;
+        std::cout << e.what() << std::endl;
+        throw;
+      }
+    }
+    std::map<std::string, std::string>::const_iterator begin() const { return _configMap.begin(); }
+    std::map<std::string, std::string>::const_iterator end() const { return _configMap.end(); }
+  };
+
+  using MapType = ConfigMap;
+
  public:
   enum class InputType { WZDMA, FILEDMA, TCPIP, MICRONDMA, FILE };
 
@@ -152,6 +172,6 @@ class config {
   const std::string getSconeBoard() const { return vmap.at("scone_board"); }
 
  private:
-  std::map<std::string, std::string> vmap;
+  MapType vmap;
 };
 #endif