xvilla.h

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   * cursor becomes unavailable due to updating database.
   */
  virtual void put(const char* kbuf, int ksiz, const char* vbuf, int vsiz,
                   int dmode = Villa::DOVER) throw(Villa_error);
  /**
   * Delete a record.
   * @param kbuf the pointer to the region of a key.
   * @param ksiz the size of the region of the key.  If it is negative, the size is assigned
   * with `std::strlen(kbuf)'.
   * @throw Villa_error if an error occures or no record corresponds.
   * @note When the key of duplicated records is specified, the first record of the same key
   * is deleted.  The cursor becomes unavailable due to updating database.
   */
  virtual void out(const char* kbuf, int ksiz) throw(Villa_error);
  /**
   * Retrieve a record.
   * @param kbuf the pointer to the region of a key.
   * @param ksiz the size of the region of the key.  If it is negative, the size is assigned
   * with `std::strlen(kbuf)'.
   * @param sp the pointer to a variable to which the size of the region of the return value
   * is assigned.  If it is 0, it is not used.
   * @return the pointer to the region of the value of the corresponding record.
   * @throw Villa_error if an error occures or no record corresponds.
   * @note When the key of duplicated records is specified, the value of the first record of
   * the same key is selected.  Because an additional zero code is appended at the end of the
   * region of the return value, the return value can be treated as a character string.
   * Because the region of the return value is allocated with the `std::malloc' call, it
   * should be released with the `std::free' call if it is no longer in use.
   */
  virtual char* get(const char* kbuf, int ksiz, int* sp = 0) throw(Villa_error);
  /**
   * Get the number of records corresponding a key.
   * @param kbuf the pointer to the region of a key.
   * @param ksiz the size of the region of the key.  If it is negative, the size is assigned
   * with `std::strlen(kbuf)'.
   * @return the number of corresponding records.  If no record corresponds, 0 is returned.
   * @throw Villa_error if an error occures.
   */
  virtual int vnum(const char* kbuf, int ksiz) throw(Villa_error);
  /**
   * Move the cursor to the first record.
   * @throw Villa_error if an error occures or there is no record in the database.
   */
  virtual void curfirst() throw(Villa_error);
  /**
   * Move the cursor to the last record.
   * @throw Villa_error if an error occures or there is no record in the database.
   */
  virtual void curlast() throw(Villa_error);
  /**
   * Move the cursor to the previous record.
   * @throw Villa_error if an error occures or there is no previous record.
   */
  virtual void curprev() throw(Villa_error);
  /**
   * Move the cursor to the next record.
   * @throw Villa_error if an error occures or there is no next record.
   */
  virtual void curnext() throw(Villa_error);
  /**
   * Move the cursor to positon around a record.
   * @param kbuf the pointer to the region of a key.
   * @param ksiz the size of the region of the key.  If it is negative, the size is assigned
   * with `std::strlen(kbuf)'.
   * @param jmode detail adjustment: `Villa::JFORWARD', which means that the cursor is set to
   * the first record of the same key and that the cursor is set to the next substitute if
   * completely matching record does not exist, `Villa::JBACKWARD', which means that the cursor
   * is set to the last record of the same key and that the cursor is set to the previous
   * substitute if completely matching record does not exist.
   * @throw Villa_error if an error occures or there is no record corresponding the condition.
   */
  virtual void curjump(const char* kbuf, int ksiz, int jmode = Villa::JFORWARD)
    throw(Villa_error);
  /**
   * Get the key of the record where the cursor is.
   * @param sp the pointer to a variable to which the size of the region of the return value
   * is assigned.  If it is 0, it is not used.
   * @return the pointer to the region of the key of the corresponding record.
   * @throw Villa_error if an error occures or no record corresponds to the cursor.
   * @note Because an additional zero code is appended at the end of the region of the return
   * value, the return value can be treated as a character string.  Because the region of the
   * return value is allocated with the `std::malloc' call, it should be released with the
   * `std::free' call if it is no longer in use.
   */
  virtual char* curkey(int* sp = 0) throw(Villa_error);
  /**
   * Get the value of the record where the cursor is.
   * @param sp the pointer to a variable to which the size of the region of the return value
   * is assigned.  If it is 0, it is not used.
   * @return the pointer to the region of the value of the corresponding record.
   * @throw Villa_error if an error occures or no record corresponds to the cursor.
   * @note Because an additional zero code is appended at the end of the region of the return
   * value, the return value can be treated as a character string.  Because the region of the
   * return value is allocated with the `std::malloc' call, it should be released with the
   * `std::free' call if it is no longer in use.
   */
  virtual char* curval(int* sp = 0) throw(Villa_error);
  /**
   * Set the tuning parameters for performance.
   * @param lrecmax the max number of records in a leaf node of B+ tree.  If it is not more
   * than 0, the default value is specified.
   * @param nidxmax the max number of indexes in a non-leaf node of B+ tree.  If it is not more
   * than 0, the default value is specified.
   * @param lcnum the max number of caching leaf nodes.  If it is not more than 0, the default
   * value is specified.
   * @param ncnum the max number of caching non-leaf nodes.  If it is not more than 0, the
   * default value is specified.
   * @throw Villa_error if an error occures.
   * @note The default setting is equivalent to `settuning(49, 192, 1024, 512)'.  Because tuning
   * paremeters are not saved in a database, you should specify them every opening a database.
   */
  virtual void settuning(int lrecmax, int nidxmax, int lcnum, int ncnum) throw(Villa_error);
  /**
   * Synchronize updating contents with the file and the device.
   * @throw Villa_error if an error occures.
   * @note This function is useful when another process uses the connected database file.  This
   * function shuold not be used while the transaction is activated.
   */
  virtual void sync() throw(Villa_error);
  /**
   * Optimize a database.
   * @throw Villa_error if an error occures.
   * @note In an alternating succession of deleting and storing with overwrite or concatenate,
   * dispensable regions accumulate.  This function is useful to do away with them.  This
   * function shuold not be used while the transaction is activated.
   */
  virtual void optimize() throw(Villa_error);
  /**
   * Get the name of the database.
   * @return the pointer to the region of the name of the database.
   * @throw Villa_error if an error occures.
   * @note Because the region of the return value is allocated with the `std::malloc' call,
   * it should be released with the `std::free' call if it is no longer in use.
   */
  virtual char* name() throw(Villa_error);
  /**
   * Get the size of the database file.
   * @return the size of the database file.
   * @throw Villa_error if an error occures.
   * @note Because of the I/O buffer, the return value may be less than the real size.
   */
  virtual int fsiz() throw(Villa_error);
  /**
   * Get the number of the leaf nodes of B+ tree.
   * @return the number of the leaf nodes.
   * @throw Villa_error if an error occures.
   */
  virtual int lnum() throw(Villa_error);
  /**
   * Get the number of the non-leaf nodes of B+ tree.
   * @return the number of the non-leaf nodes.
   * @throw Villa_error if an error occures.
   */
  virtual int nnum() throw(Villa_error);
  /**
   * Get the number of the records stored in a database.
   * @return the number of the records stored in the database.
   * @throw Villa_error if an error occures.
   */
  virtual int rnum() throw(Villa_error);
  /**
   * Check whether the database handle is a writer or not.
   * @return true if the handle is a writer, false if not.
   * @throw Villa_error if an error occures.
   */
  virtual bool writable() throw(Villa_error);
  /**
   * Check whether the database has a fatal error or not.
   * @return true if the database has a fatal error, false if not.
   * @throw Villa_error if an error occures.
   */
  virtual bool fatalerror() throw(Villa_error);
  /**
   * Get the inode number of the database file.
   * @return the inode number of the database file.
   * @throw Villa_error if an error occures.
   */
  virtual int inode() throw(Villa_error);
  /**
   * Begin the transaction.
   * @throw Villa_error if an error occures.
   * @note If a thread is already in the transaction, the other threads block until the prius
   * is out of the transaction.  Only one transaction can be activated with a database handle
   * at the same time.
   */
  virtual void tranbegin() throw(Villa_error);
  /**
   * Commit the transaction.
   * @throw Villa_error if an error occures.
   * @note Updating a database in the transaction is fixed when it is committed successfully.
   * Any other thread except for the one which began the transaction should not call this
   * function.
   */
  virtual void trancommit() throw(Villa_error);
  /**
   * Abort the transaction.
   * @throw Villa_error if an error occures.
   * @note Updating a database in the transaction is discarded when it is aborted.  The state
   * of the database is rollbacked to before transaction.  Any other thread except for the one
   * which began the transaction should not call this function.
   */
  virtual void tranabort() throw(Villa_error);
  /**
   * Store a record.
   * @param key reference to a key object.
   * @param val reference to a value object.
   * @param replace whether the existing value is to be overwritten or not.
   * @throw Villa_error if an error occures or replace is cancelled.
   */
  virtual void storerec(const Datum& key, const Datum& val, bool replace = true)
    throw(Villa_error);
  /**
   * Delete a record.
   * @param key reference to a key object.
   * @throw Villa_error if an error occures or no record corresponds.
   */
  virtual void deleterec(const Datum& key) throw(Villa_error);
  /**
   * Fetch a record.
   * @param key reference to a key object.
   * @return a temporary instance of the value of the corresponding record.
   * @throw Villa_error if an error occures or no record corresponds.
   */
  virtual Datum fetchrec(const Datum& key) throw(Villa_error);
  /**
   * Get the first key.
   * @return a temporary instance of the key of the first record.
   * @throw Villa_error if an error occures or no record corresponds.
   */
  virtual Datum firstkey() throw(Villa_error);
  /**
   * Get the next key.
   * @return a temporary instance of the key of the next record.
   * @throw Villa_error if an error occures or no record corresponds.
   */
  virtual Datum nextkey() throw(Villa_error);
  /**
   * Check whether a fatal error occured or not.
   * @return true if the database has a fatal error, false if not.
   * @throw Villa_error if an error occures.
   */
  virtual bool error() throw(Villa_error);
  //----------------------------------------------------------------
  // private member variables
  //----------------------------------------------------------------
private:
  VILLA* villa;                       ///< internal database handle
  pthread_mutex_t tranmutex;          ///< mutex for the transaction
  //----------------------------------------------------------------
  // private member functions
  //----------------------------------------------------------------
private:
  /** copy constructor: This should not be used. */
  Villa(const Villa& villa) throw(Villa_error);
  /** assignment operator: This should not be used. */
  Villa& operator =(const Villa& villa) throw(Villa_error);
};



#endif                                   /* duplication check */


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