cpp-json/json/json_direct_map_binder.hpp

//
//  json_direct_map_binder.hpp
//  json
//
//  Created by Sam Jaffe on 4/23/16.
//

#pragma once

namespace json { namespace binder {
  template <typename T, typename V>
  class direct_binder<T, std::map<std::string, V> > : public binder_impl<T> {
  public:
    direct_binder(std::vector<V> T::*p, binder<V> const&i);
    virtual binder_impl<T>* clone() const override { return new direct_binder(*this); }
    
    virtual void parse(T& val, char const*& data) const override {
      const char ch = json::helper::get_next_element(data);
      if (ch != '{') {
        throw json::malformed_json_exception("Expected an array type");
      }
      ++data;
      
      V to_make;
      std::map<std::string, V>& vec = val.*ptr;
      std::string key;
      while (*data && *data != '}') {
        json::helper::parse_string(key, data);
        if (json::helper::get_next_element(data) != ':') {
          throw json::malformed_json_exception(std::string("Expected key:value pair delimited by ':', got '") + *data + "' instead");
        }
        impl.parse(to_make, ++data);
        vec.emplace(key, to_make);
        json::helper::advance_to_boundary('}', data);
      }
      if (*data) ++data;
      else throw json::malformed_json_exception("Reached end of parse string without finding object end");
    }
    
    virtual void write(T const& val, std::string & data) const override {
      data += "{";
      std::map<std::string, V> const & map = val.*ptr;
      for (typename std::map<std::string, V>::const_iterator it = map.begin(),
           end = map.end(); it != end; ++it) {
        data += "\"" + it->first + "\":";
        impl.write(it->second, data);
        data += ",";
      }
      data.back() = '}';
    }
  private:
    std::map<std::string, V> T::*ptr;
    binder<V> impl;
  };
} }