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#ifndef JUBATUS_UTIL_LANG_CAST_H_
#define JUBATUS_UTIL_LANG_CAST_H_

#include <string>
#include <sstream>
#include <stdexcept>
#include <typeinfo>

namespace jubatus {
namespace util{
namespace lang{

namespace detail{

template <typename Target, typename Source, bool Same>
class lexical_cast{
public:
  static Target cast(const Source &arg){
    Target ret;
    std::stringstream ss;
    if (!(ss<<arg && ss>>ret))
      throw std::bad_cast();
    
    return ret;
  }
};

template <typename Target, typename Source>
class lexical_cast<Target, Source, true>{
public:
  static Target cast(const Source &arg){
    return arg;
  }  
};

template <typename Source>
class lexical_cast<std::string, Source, false>{
public:
  static std::string cast(const Source &arg){
    std::ostringstream ss;
    ss<<arg;
    return ss.str();
  }
};

template <typename Target>
class lexical_cast<Target, std::string, false>{
public:
  static Target cast(const std::string &arg){
    Target ret;
    std::istringstream ss(arg);
    if (!(ss>>ret))
      throw std::bad_cast();
    return ret;
  }
};

template <typename T1, typename T2>
struct is_same {
  static const bool value = false;
};

template <typename T>
struct is_same<T, T>{
  static const bool value = true;
};

} // detail

template<typename Target, typename Source>
Target lexical_cast(const Source &arg)
{
  return detail::lexical_cast<Target, Source, detail::is_same<Target, Source>::value>::cast(arg);
}

} // lang
} // util
} // jubatus
#endif // #ifndef JUBATUS_UTIL_LANG_CAST_H_
