/*
 * $Id$
 */

/*
 * Harbour Project source code:
 * EMPTY() function
 *
 * Copyright 1999 {list of individual authors and e-mail addresses}
 * www - http://www.harbour-project.org
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version, with one exception:
 *
 * The exception is that if you link the Harbour Runtime Library (HRL)
 * and/or the Harbour Virtual Machine (HVM) with other files to produce
 * an executable, this does not by itself cause the resulting executable
 * to be covered by the GNU General Public License. Your use of that
 * executable is in no way restricted on account of linking the HRL
 * and/or HVM code into it.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA (or visit
 * their web site at http://www.gnu.org/).
 *
 */

#include "extend.h"
#include "itemapi.h"

/*  $DOC$
 *  $FUNCNAME$
 *      EMPTY
 *  $CATEGORY$
 *
 *  $ONELINER$
 *      Checks if the passed argument is empty.
 *  $SYNTAX$
 *      EMPTY( <xExp> ) --> <lIsEmpty>
 *  $ARGUMENTS$
 *      <xExp> is any valid expression.
 *  $RETURNS$
 *      A logical value. It is true (.T.) if the passed argument is empty
 *      otherwise it is false (.F.).
 *  $DESCRIPTION$
 *      This function checks if an expression has empty value and returns a
 *      logical indicating whether it the expression is empty or not.
 *  $EXAMPLES$
 *      ? Empty( "I'm not empty" )
 *  $TESTS$
 *      function Test()
 *         ? Empty( 1 )       --> .f.
 *         ? Empty( Date() )  --> .f.
 *         ? Empty( .f. )     --> .t.
 *      return nil
 *  $STATUS$
 *      R
 *  $COMPLIANCE$
 *      EMPTY() is fully CA-Clipper compliant.
 *  $SEEALSO$
 *      LEN
 *  $END$
 */

HARBOUR HB_EMPTY( void )
{
   PHB_ITEM pItem = hb_param( 1, IT_ANY );

   /* NOTE: Double safety to ensure that a parameter was really passed,
            compiler checks this, but a direct hb_vmDo() call
            may not do so. [vszel] */

   if( pItem )
   {
      switch( pItem->type & ~IT_BYREF )
      {
         case IT_ARRAY:
            hb_retl( hb_arrayLen( pItem ) == 0 );
            break;

         case IT_STRING:
         case IT_MEMO:
            hb_retl( hb_strEmpty( hb_itemGetCPtr( pItem ), hb_itemGetCLen( pItem ) ) );
            break;

         case IT_INTEGER:
            hb_retl( hb_itemGetNI( pItem ) == 0 );
            break;

         case IT_LONG:
            hb_retl( hb_itemGetNL( pItem ) == 0 );
            break;

         case IT_DOUBLE:
            hb_retl( hb_itemGetND( pItem ) == 0.0 );
            break;

         case IT_DATE:
            /* NOTE: This is correct ! Get the date as long value. */
            hb_retl( hb_itemGetNL( pItem ) == 0 );
            break;

         case IT_LOGICAL:
            hb_retl( ! hb_itemGetL( pItem ) );
            break;

         case IT_BLOCK:
            hb_retl( FALSE );
            break;

         default:
            hb_retl( TRUE );
            break;
      }
   }
   else
      hb_retl( TRUE );
}