template<typename ENUM>
class Stringifier<ENUM, typename boost::enable_if<boost::is_enum<ENUM> >::type> {
  static const char * values[]; // array with the enum strings.
  static std::size_t size;      // Number of elements of the ENUM string arrays.
public:
  /// Global static instance of the Stringifier.
  static Stringifier & getInstance()
  {
    static Stringifier globalInstance;
    return globalInstance;
  }
  // Returns the string representation of the ENUM value \a e as a C string.
  // If string is not available an exception is thrown.
  virtual void str(ENUM const & e, std::string & s) const
  {
    if(e >= 0 && e < int(size))
      s = values[e];
    else // throw exception
     ;
  }

  // Returns the ENUM value of the string representation of an ENUM value if possible,
  // ENUM(0) otherwise or ENUM(size) if you like.
  virtual bool value(std::string const & str, ENUM & v) const
  {
    std::size_t i = 0;
    for(; i < size; ++i)
      if(values[i] == str) break;
    bool ok = (i != size);
    v = ok ? ENUM(i) : ENUM(0);
    return ok;
  }
};