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xvilla.h

/*************************************************************************************************
 * C++ API of Villa, the advanced API of QDBM
 *                                                      Copyright (C) 2000-2005 Mikio Hirabayashi
 * This file is part of QDBM, Quick Database Manager.
 * QDBM is free software; you can redistribute it and/or modify it under the terms of the GNU
 * Lesser General Public License as published by the Free Software Foundation; either version
 * 2.1 of the License or any later version.  QDBM 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 Lesser General Public License for more
 * details.
 * You should have received a copy of the GNU Lesser General Public License along with QDBM; if
 * not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307 USA.
 *************************************************************************************************/


#ifndef _XVILLA_H                        /* duplication check */
#define _XVILLA_H


#include <xqdbm.h>
#include <xadbm.h>

extern "C" {
#include <depot.h>
#include <cabin.h>
#include <villa.h>
#include <stdlib.h>
}



/**
 * Error container for Villa.
 */
00036 class qdbm::Villa_error : public virtual DBM_error {
  //----------------------------------------------------------------
  // public member functions
  //----------------------------------------------------------------
public:
  /**
   * Create an instance.
   */
  Villa_error() throw();
  /**
   * Create an instance.
   * @param ecode the error code.
   */
  Villa_error(int ecode) throw();
  /**
   * Copy constructor.
   * @param ve a source instance.
   */
  Villa_error(const Villa_error& ve) throw();
  /**
   * Release resources of the instance.
   */
  virtual ~Villa_error() throw();
  /**
   * Assignment operator.
   * @param ve a source instance.
   * @return reference to itself.
   */
  Villa_error& operator =(const Villa_error& ve) throw();
  /**
   * Assignment operator.
   * @param ecode the error code.
   * @return reference to itself.
   */
  Villa_error& operator =(int ecode) throw();
  /**
   * Equality operator.
   * @param ve a comparing instance.
   * @return true if both equal, else, false.
   */
  virtual bool operator ==(const Villa_error& ve) const throw();
  /**
   * Inequality operator.
   * @param ve a comparing instance.
   * @return true if both do not equal, else, false.
   */
  virtual bool operator !=(const Villa_error& ve) const throw();
  /**
   * Equality operator.
   * @param ecode a comparing error code.
   * @return true if both equal, else, false.
   */
  virtual bool operator ==(int ecode) const throw();
  /**
   * Inequality operator.
   * @param ecode a comparing error code.
   * @return true if both do not equal, else, false.
   */
  virtual bool operator !=(int ecode) const throw();
  /**
   * Cast operator into pointer to char.
   * @return the pointer to the string.
   */
  virtual operator const char*() const throw();
  /**
   * Get the error code.
   * @return the error code.
   */
  virtual int code() const throw();
  /**
   * Get the error message.
   * @return the pointer to the string.
   */
  virtual const char* message() const throw();
  //----------------------------------------------------------------
  // private member variables
  //----------------------------------------------------------------
private:
  /** The error code. */
00115   int ecode;
};



/**
 * C++ API of Villa, the basic API of QDBM.
 */
class qdbm::Villa : public virtual ADBM {
  //----------------------------------------------------------------
  // public static member constants
  //----------------------------------------------------------------
public:
00128   static const int ENOERR;            ///< error code: no error
00129   static const int EFATAL;            ///< error code: with fatal error
00130   static const int EMODE;             ///< error code: invalid mode
00131   static const int EBROKEN;           ///< error code: broken database file
00132   static const int EKEEP;             ///< error code: existing record
00133   static const int ENOITEM;           ///< error code: no item found
00134   static const int EALLOC;            ///< error code: memory allocation error
00135   static const int EMAP;              ///< error code: memory mapping error
00136   static const int EOPEN;             ///< error code: open error
00137   static const int ECLOSE;            ///< error code: close error
00138   static const int ETRUNC;            ///< error code: trunc error
00139   static const int ESYNC;             ///< error code: sync error
00140   static const int ESTAT;             ///< error code: stat error
00141   static const int ESEEK;             ///< error code: seek error
00142   static const int EREAD;             ///< error code: read error
00143   static const int EWRITE;            ///< error code: write error
00144   static const int ELOCK;             ///< error code: lock error
00145   static const int EUNLINK;           ///< error code: unlink error
00146   static const int EMKDIR;            ///< error code: mkdir error
00147   static const int ERMDIR;            ///< error code: rmdir error
00148   static const int EMISC;             ///< error code: miscellaneous error
00149   static const int OREADER;           ///< open mode: open as a reader
00150   static const int OWRITER;           ///< open mode: open as a writer
00151   static const int OCREAT;            ///< open mode: writer creating
00152   static const int OTRUNC;            ///< open mode: writer truncating
00153   static const int ONOLCK;            ///< open mode: open without locking
00154   static const int OLCKNB;            ///< open mode: lock without blocking
00155   static const int OZCOMP;            ///< open mode: compress leaves
00156   static const int DOVER;             ///< write mode: overwrite the existing value
00157   static const int DKEEP;             ///< write mode: keep the existing value
00158   static const int DDUP;              ///< write mode: concatenate values
00159   static const int JFORWARD;          ///< jump mode: step forward
00160   static const int JBACKWARD;         ///< jump mode: step backward
  //----------------------------------------------------------------
  // public static member functions
  //----------------------------------------------------------------
public:
  /**
   * Get the version information.
   * @return the string of the version information.
   */
  static const char* version() throw();
  /**
   * Remove a database directory.
   * @param name the name of a database directory.
   * @throw Villa_error if an error occurs.
   */
  static void remove(const char* name) throw(Villa_error);
  /**
   * Compare keys of two records by lexical order.
   * @param aptr the pointer to the region of one key.
   * @param asiz the size of the region of one key.
   * @param bptr the pointer to the region of the other key.
   * @param bsiz the size of the region of the other key.
   * @return positive if the former is big, negative if the latter is big, 0 if both are
   * equivalent.
   */
  static int cmplex(const char *aptr, int asiz, const char *bptr, int bsiz) throw();
  /**
   * Compare keys of two records as integers.
   * @param aptr the pointer to the region of one key.
   * @param asiz the size of the region of one key.
   * @param bptr the pointer to the region of the other key.
   * @param bsiz the size of the region of the other key.
   * @return positive if the former is big, negative if the latter is big, 0 if both are
   * equivalent.
   */
  static int cmpint(const char *aptr, int asiz, const char *bptr, int bsiz) throw();
  /**
   * Compare keys of two records as numbers of big endian.
   * @param aptr the pointer to the region of one key.
   * @param asiz the size of the region of one key.
   * @param bptr the pointer to the region of the other key.
   * @param bsiz the size of the region of the other key.
   * @return positive if the former is big, negative if the latter is big, 0 if both are
   * equivalent.
   */
  static int cmpnum(const char *aptr, int asiz, const char *bptr, int bsiz) throw();
  /**
   * Compare keys of two records as decimal strings.
   * @param aptr the pointer to the region of one key.
   * @param asiz the size of the region of one key.
   * @param bptr the pointer to the region of the other key.
   * @param bsiz the size of the region of the other key.
   * @return positive if the former is big, negative if the latter is big, 0 if both are
   * equivalent.
   */
  static int cmpdec(const char *aptr, int asiz, const char *bptr, int bsiz) throw();
  //----------------------------------------------------------------
  // public member functions
  //----------------------------------------------------------------
public:
  /**
   * Get the database handle.
   * @param name the name of a database file.
   * @param omode the connection mode: `Villa::OWRITER' as a writer, `Villa::OREADER' as
   * a reader.  If the mode is `Villa::OWRITER', the following may be added by bitwise or:
   * `Villa::OCREAT', which means it creates a new database if not exist, `Villa::OTRUNC',
   * which means it creates a new database regardless if one exists, `Villa::OZCOMP', which means
   * leaves in the database are compressed.  Both of `Villa::OREADER' and `Villa::OWRITER' can
   * be added to by bitwise or: `Villa::ONOLCK', which means it opens a database file without
   * file locking, or `Villa::OLCKNB', which means locking is performed without blocking.
   * @param cmp the comparing function: `Villa::cmplex' comparing keys in lexical order,
   * `Villa::cmpint' comparing keys as objects of `int' in native byte order, `Villa::cmpnum'
   * comparing keys as numbers of big endian, `Villa::cmpdec' comparing keys as decimal strings.
   * Any function compatible with them can be assigned to the comparing function.  The comparing
   * function should be kept same in the life of a database.
   * @throw Villa_error if an error occurs.
   * @note While connecting as a writer, an exclusive lock is invoked to the database file.
   * While connecting as a reader, a shared lock is invoked to the database file.  The thread
   * blocks until the lock is achieved.  `Villa::OZCOMP' is available only if QDBM was built with
   * ZLIB enabled.  If `Villa::ONOLCK' is used, the application is responsible for exclusion
   * control.
   */
  Villa(const char* name, int omode = Villa::OREADER, VLCFUNC cmp = Villa::cmplex)
    throw(Villa_error);
  /**
   * Release the resources.
   * @note If the database handle is not closed yet, it is closed.
   */
  virtual ~Villa() throw();
  /**
   * Close the database handle.
   * @throw Villa_error if an error occurs.
   * @note Updating a database is assured to be written when the handle is closed.  If a writer
   * opens a database but does not close it appropriately, the database will be broken.  If the
   * transaction is activated and not committed, it is aborted.
   */
  virtual void close() throw(Villa_error);
  /**
   * Store 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 vbuf the pointer to the region of a value.
   * @param vsiz the size of the region of the value.  If it is negative, the size is assigned
   * with `std::strlen(vbuf)'.
   * @param dmode behavior when the key overlaps, by the following values: `Villa::DOVER',
   * which means the specified value overwrites the existing one, `Villa::DKEEP', which means
   * the existing value is kept, `Villa::DDUP', which means duplication of keys is allowed.
   * @throw Villa_error if an error occurs or replace is cancelled.
   * @note A duplicated record is stored at the tail of the records of the same key.  The
   * 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 occurs 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 occurs 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 occurs.
   */
  virtual int vnum(const char* kbuf, int ksiz) throw(Villa_error);
  /**
   * Move the cursor to the first record.
   * @throw Villa_error if an error occurs 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 occurs 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 occurs 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 occurs 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 occurs 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 occurs 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 occurs 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 occurs.
   * @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 occurs.
   * @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 occurs.
   * @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 occurs.
   * @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 occurs.
   * @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 occurs.
   */
  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 occurs.
   */
  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 occurs.
   */
  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 occurs.
   */
  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 occurs.
   */
  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 occurs.
   */
  virtual int inode() throw(Villa_error);
  /**
   * Get the last modified time of the database.
   * @return the last modified time the database.
   * @throw Villa_error if an error occurs.
   */
  virtual int mtime() throw(Villa_error);
  /**
   * Begin the transaction.
   * @throw Villa_error if an error occurs.
   * @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 occurs.
   * @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 occurs.
   * @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 occurs 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 occurs 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 occurs 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 occurs 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 occurs 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 occurs.
   */
  virtual bool error() throw(Villa_error);
  //----------------------------------------------------------------
  // private member variables
  //----------------------------------------------------------------
private:
00522   VILLA* villa;                       ///< internal database handle
00523   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 */


/* END OF FILE */

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