~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, Inc.

 *

 *  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/function/math/minus.h>

namespace drizzled

{

/**

  The following function is here to allow the user to force

  subtraction of UNSIGNED BIGINT to return negative values.

*/

void Item_func_minus::fix_length_and_dec()

{

  Item_num_op::fix_length_and_dec();

  if (unsigned_flag)

    unsigned_flag= 0;

}

double Item_func_minus::real_op()

{

  double value= args[0]->val_real() - args[1]->val_real();

  if ((null_value=args[0]->null_value || args[1]->null_value))

    return 0.0;

  return fix_result(value);

}

int64_t Item_func_minus::int_op()

{

  int64_t value=args[0]->val_int() - args[1]->val_int();

  if ((null_value=args[0]->null_value || args[1]->null_value))

    return 0;

  return value;

}

/**

  See Item_func_plus::decimal_op for comments.

*/

type::Decimal *Item_func_minus::decimal_op(type::Decimal *decimal_value)

{

  type::Decimal value1, *val1;

  type::Decimal value2, *val2=

  val1= args[0]->val_decimal(&value1);

  if ((null_value= args[0]->null_value))

    return 0;

  val2= args[1]->val_decimal(&value2);

  if (!(null_value= (args[1]->null_value ||

                     (class_decimal_sub(E_DEC_FATAL_ERROR, decimal_value, val1,

                                     val2) > 3))))

    return decimal_value;

  return 0;

}

} /* namespace drizzled */