Value.h

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/***************************************************************************
 *
 * Copyright (C) 2009-2011 Cassio Neri Moreira
 *
 * This file is part of the KeyValue library.
 *
 * The KeyValue library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * The KeyValue library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with KeyValue. If not, see <http://www.gnu.org/licenses/>.
 *
 * If you modify this library, or any covered work, by linking or combining
 * it with Excel (or a modified version of that program), containing parts
 * covered by the terms of End-User License Agreement for Microsoft
 * Software, the licensors of KeyValue grant you additional permission to
 * convey the resulting work.
 *
 **************************************************************************/

#ifndef KEYVALUE_VALUE_VALUE_H_
#define KEYVALUE_VALUE_VALUE_H_

#include <iosfwd>

#include <boost/variant.hpp>

#include "keyvalue/value/Matrix.h"
#include "keyvalue/value/Single.h"
#include "keyvalue/value/Vector.h"

namespace keyvalue {

namespace value {

class Value {

public:

  typedef ::boost::variant<Single, Vector, Matrix> DataType_;

  Value();

  Value(const DataType_& data);

  template <typename Rhs>
  Value(const Rhs& rhs);

  template <typename Rhs>
  Value&
  operator=(const Rhs& rhs);

  bool
  operator==(const Value& rhs) const;

  template <typename Type>
  const Type*
  get() const;

  template <typename Type>
  Type*
  get();

private:

  DataType_ data_;

}; // class Value

::std::ostream&
operator<<(::std::ostream& os, const Value& rhs);

template <typename Rhs>
struct Parent;

template <>
struct Parent<Value::DataType_> {
  typedef Value Type_;
};

template <>
struct Parent<Single> {
  typedef Value::DataType_ Type_;
};

template <>
struct Parent<Vector> {
  typedef Value::DataType_ Type_;
};

template <>
struct Parent<Matrix> {
  typedef Value::DataType_ Type_;
};

/*--------------------------------------------------------------------------
 * Value()
 *------------------------------------------------------------------------*/

template <typename Rhs>
Value::Value(const Rhs& rhs) :
  data_(Value(typename Parent<Rhs>::Type_(rhs)).data_) {

  /*
   * If you get an error here about 'keyvalue::value::Parent<Rhs>', this
   * means that Rhs isn't in a lower level in the hierarchy.
   */
}

/*--------------------------------------------------------------------------
 * operator=()
 *------------------------------------------------------------------------*/

template <typename Rhs>
Value&
Value::operator=(const Rhs& rhs) {

  /*
   * If you get an error here about 'keyvalue::value::Parent<P>', this
   * means that Rhs isn't in a lower level in the hierarchy.
   */

  return *this = typename Parent<Rhs>::Type_(rhs);
}

} // namespace value
} // namespace keyvalue

#endif // KEYVALUE_VALUE_VALUE_H_