~drizzle-trunk/drizzle/development

/* Copyright (C) 2004 MySQL AB

   This program 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; version 2 of the License.

   This program 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 this program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifdef USE_PRAGMA_INTERFACE

#pragma interface			/* gcc class interface */

#endif

/**

  This class represents abstract time zone and provides 

  basic interface for DRIZZLE_TIME <-> my_time_t conversion.

  Actual time zones which are specified by DB, or via offset 

  or use system functions are its descendants.

*/

class Time_zone: public Sql_alloc 

{

public:

  Time_zone() {}                              /* Remove gcc warning */

  /**

    Converts local time in broken down DRIZZLE_TIME representation to 

    my_time_t (UTC seconds since Epoch) represenation.

    Returns 0 in case of error. Sets in_dst_time_gap to true if date provided

    falls into spring time-gap (or lefts it untouched otherwise).

  */

  virtual my_time_t TIME_to_gmt_sec(const DRIZZLE_TIME *t, 

                                    bool *in_dst_time_gap) const = 0;

  /**

    Converts time in my_time_t representation to local time in

    broken down DRIZZLE_TIME representation.

  */

  virtual void   gmt_sec_to_TIME(DRIZZLE_TIME *tmp, my_time_t t) const = 0;

  /**

    Because of constness of String returned by get_name() time zone name 

    have to be already zeroended to be able to use String::ptr() instead

    of c_ptr().

  */

  virtual const String * get_name() const = 0;

  /** 

    We need this only for surpressing warnings, objects of this type are

    allocated on MEM_ROOT and should not require destruction.

  */

  virtual ~Time_zone() {};

};

extern Time_zone * my_tz_UTC;

extern Time_zone * my_tz_SYSTEM;

extern Time_zone * my_tz_OFFSET0;

extern Time_zone * my_tz_find(THD *thd, const String *name);

extern bool     my_tz_init(THD *org_thd, const char *default_tzname, bool bootstrap);

extern void        my_tz_free();

extern my_time_t   sec_since_epoch_TIME(DRIZZLE_TIME *t);