~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems

 *

 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include "config.h"

#include "drizzled/temporal.h"

#include "drizzled/error.h"

#include "drizzled/function/time/hour.h"

namespace drizzled

{

int64_t Item_func_hour::val_int()

{

  assert(fixed);

  if (args[0]->is_null())

  {

    /* For NULL argument, we return a NULL result */

    null_value= true;

    return 0;

  }

  /* 

   * Because of the ridiculous way in which MySQL handles

   * TIME values (it does implicit integer -> string conversions

   * but only for DATETIME, not TIME values) we must first 

   * try a conversion into a TIME from a string.  If this

   * fails, we fall back on a DATETIME conversion.  This is

   * necessary because of the fact that DateTime::from_string()

   * looks first for DATETIME, then DATE regex matches.  6 consecutive

   * numbers, say 231130, will match the DATE regex YYMMDD

   * with no TIME part, but MySQL actually implicitly treats

   * parameters to SECOND(), HOUR(), and MINUTE() as TIME-only

   * values and matches 231130 as HHmmSS!

   *

   * Oh, and Brian Aker MADE me do this. :) --JRP

   */

  Time temporal_time;

  char time_buff[DRIZZLE_MAX_LENGTH_DATETIME_AS_STRING];

  String tmp_time(time_buff,sizeof(time_buff), &my_charset_utf8_bin);

  String *time_res= args[0]->val_str(&tmp_time);

  if (! temporal_time.from_string(time_res->c_ptr(), time_res->length()))

  {

    /* 

     * OK, we failed to match the first argument as a string

     * representing a time value, so we grab the first argument 

     * as a DateTime object and try that for a match...

     */

    DateTime temporal_datetime;

    Item_result arg0_result_type= args[0]->result_type();

    switch (arg0_result_type)

    {

      case DECIMAL_RESULT: 

        /* 

         * For doubles supplied, interpret the arg as a string, 

         * so intentionally fall-through here...

         * This allows us to accept double parameters like 

         * 19971231235959.01 and interpret it the way MySQL does:

         * as a TIMESTAMP-like thing with a microsecond component.

         * Ugh, but need to keep backwards-compat.

         */

      case STRING_RESULT:

        {

          char buff[DRIZZLE_MAX_LENGTH_DATETIME_AS_STRING];

          String tmp(buff,sizeof(buff), &my_charset_utf8_bin);

          String *res= args[0]->val_str(&tmp);

          if (! temporal_datetime.from_string(res->c_ptr(), res->length()))

          {

            /* 

            * Could not interpret the function argument as a temporal value, 

            * so throw an error and return 0

            */

            my_error(ER_INVALID_DATETIME_VALUE, MYF(0), res->c_ptr());

            return 0;

          }

        }

        break;

      case INT_RESULT:

        if (temporal_datetime.from_int64_t(args[0]->val_int()))

          break;

        /* Intentionally fall-through on invalid conversion from integer */

      default:

        {

          /* 

          * Could not interpret the function argument as a temporal value, 

          * so throw an error and return 0

          */

          null_value= true;

          char buff[DRIZZLE_MAX_LENGTH_DATETIME_AS_STRING];

          String tmp(buff,sizeof(buff), &my_charset_utf8_bin);

          String *res;

          res= args[0]->val_str(&tmp);

          my_error(ER_INVALID_DATETIME_VALUE, MYF(0), res->c_ptr());

          return 0;

        }

    }

    return (int64_t) temporal_datetime.hours();

  }

  return (int64_t) temporal_time.hours();

}

} /* namespace drizzled */