NamedVectorCombinator.h

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#ifndef _MADARA_UTILITY_NAMED_VECTOR_COMBINATOR_H_
#define _MADARA_UTILITY_NAMED_VECTOR_COMBINATOR_H_
 
#include <map>
#include <set>
#include <vector>
#include <string>
#include <sstream>
#include <iterator>
 
#include "Utility.h"
#include "madara/exceptions/NameException.h"
 
namespace madara
{
namespace utility
{
class NamedVectorCombinator
{
public:
  NamedVectorCombinator() = default;
 
  inline void from_file(const std::string& name, const std::string& filename)
  {
    named_vectors_[name] = string_to_vector(file_to_string(filename));
  }
 
  inline void add(const std::string& name,
    const std::string& input)
  {
    named_vectors_[name] = string_to_vector(input);
  }
 
  inline void add(const std::string& name,
    const std::vector<std::string>& strings)
  {
    named_vectors_[name] = strings;
  }
 
  inline void merge(const std::vector<std::string> & named_vectors,
    std::vector<std::string> & result, bool throw_on_missing = true,
    bool make_unique = true, bool clear_first = true)
  {
    std::set<std::string> unique_list;
 
    if(clear_first)
    {
      result.clear();
    }
 
    for(auto name : named_vectors)
    {
      auto found = named_vectors_.find(name);
      if(found != named_vectors_.end())
      {
        // if uniqueness is not important, then copy the list over
        if(!make_unique)
        {
          result.insert(
            result.end(), found->second.begin(), found->second.end());
        }
        // if uniqueness is important, use the set instead
        else
        {
          unique_list.insert(found->second.begin(), found->second.end());
        }
      }
      else if(throw_on_missing)
      {
        std::stringstream buffer;
        buffer << "madara::utility::NamedVectorCombinator: ";
        buffer << name << " could not be found in mapped named vectors.";
         
        throw exceptions::NameException(buffer.str());
      }
    }
 
    if(make_unique)
    {
      result.insert(result.end(), unique_list.begin(), unique_list.end());
 
        // in C++17, this works and reduces copying costs. May switch then.
        // std::make_move_iterator(unique_list.begin()),
        // std::make_move_iterator(unique_list.end()));
    }
  }
 
private:
 
  std::map <std::string, std::vector<std::string>> named_vectors_; 
};
}
}
 
#endif  // _MADARA_UTILITY_NAMED_VECTOR_COMBINATOR_H_