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#ifndef MOZC_CONVERTER_CACHED_CONNECTOR_H_
#define MOZC_CONVERTER_CACHED_CONNECTOR_H_

#include "base/port.h"
#include "base/scoped_ptr.h"
#include "converter/connector_interface.h"

namespace mozc {
namespace converter {

// Provides cache mechanism for Connector.
class CachedConnector : public ConnectorInterface {
 public:
  // |cache_size| should be 2^k form of value.
  CachedConnector(ConnectorInterface *connector, int cache_size);
  virtual ~CachedConnector();

  virtual int GetTransitionCost(uint16 rid, uint16 lid) const;
  virtual int GetResolution() const;

  // Clears cache explicitly.
  void ClearCache();

 private:
  void InitializeCache() const;

  ConnectorInterface *connector_;

  // Cache data need to be mutable as they are modified in const methods. For
  // the performance, we are assuming the cache is an array, not vector.
  mutable bool cache_initialized_;
  mutable scoped_ptr<int[]> cache_key_;
  mutable scoped_ptr<int[]> cache_value_;
  const int cache_size_;
  const int hash_mask_;


  DISALLOW_COPY_AND_ASSIGN(CachedConnector);
};

}  // namespace converter
}  // namespace mozc

#endif  // MOZC_CONVERTER_CACHED_CONNECTOR_H_