charmix.c

/*
 * Harbour Project source code:
 *   CharMix() CT3 function
 *
 * Initial code: Copyright 1999-2001 Viktor Szakats (vszakats.net/harbour)
 *
 * CT3 conformity: Copyright 2001 IntTec GmbH, Neunlindenstr 32, 79106 Freiburg, Germany
 *                 Author: Martin Vogel <vogel@inttec.de>
 *
 * www - http://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, or (at your option)
 * any later version.
 *
 * 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 software; see the file COPYING.txt.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
 *
 * As a special exception, the Harbour Project gives permission for
 * additional uses of the text contained in its release of Harbour.
 *
 * The exception is that, if you link the Harbour libraries 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 Harbour library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the Harbour
 * Project under the name Harbour.  If you copy code from other
 * Harbour Project or Free Software Foundation releases into a copy of
 * Harbour, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for Harbour, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.
 *
 */

#include "ct.h"

HB_FUNC( CHARMIX )
{
   if( HB_ISCHAR( 1 ) )
   {
      const char * pcString1 = hb_parc( 1 );
      const char * pcString2;
      char * pcResult;
      HB_SIZE sLen1 = hb_parclen( 1 );
      HB_SIZE sLen2, sPos1, sPos2, sResultPos;

      if( sLen1 == 0 )
      {
         int iArgErrorMode = ct_getargerrormode();

         if( iArgErrorMode != CT_ARGERR_IGNORE )
            ct_error( ( HB_USHORT ) iArgErrorMode, EG_ARG, CT_ERROR_CHARMIX, NULL, HB_ERR_FUNCNAME, 0,
                      EF_CANDEFAULT, HB_ERR_ARGS_BASEPARAMS );

         hb_retc_null();
         return;
      }

      if( HB_ISCHAR( 2 ) )
      {
         pcString2 = hb_parc( 2 );
         sLen2 = hb_parclen( 2 );
         if( sLen2 == 0 )
         {
            int iArgErrorMode = ct_getargerrormode();

            if( iArgErrorMode != CT_ARGERR_IGNORE )
               ct_error( ( HB_USHORT ) iArgErrorMode, EG_ARG, CT_ERROR_CHARMIX,
                         NULL, HB_ERR_FUNCNAME, 0,
                         EF_CANDEFAULT, HB_ERR_ARGS_BASEPARAMS );

            hb_retclen( pcString1, sLen1 );
            return;
         }
      }
      else
      {
         pcString2 = " ";     /* NOTE: The original CT3 uses " " as 2nd string
                                 if the 2nd param is not a string ! */
         sLen2 = 1;
      }

      pcResult = ( char * ) hb_xgrab( sLen1 * 2 + 1 );
      sPos2 = sResultPos = 0;
      for( sPos1 = 0; sPos1 < sLen1; )
      {
         pcResult[ sResultPos++ ] = pcString1[ sPos1++ ];
         pcResult[ sResultPos++ ] = pcString2[ sPos2++ ];
         sPos2 %= sLen2;
      }

      hb_retclen_buffer( pcResult, sLen1 * 2 );
   }
   else
   {
      PHB_ITEM pSubst = NULL;
      int iArgErrorMode = ct_getargerrormode();

      if( iArgErrorMode != CT_ARGERR_IGNORE )
         pSubst = ct_error_subst( ( HB_USHORT ) iArgErrorMode, EG_ARG,
                                  CT_ERROR_CHARMIX, NULL, HB_ERR_FUNCNAME, 0,
                                  EF_CANSUBSTITUTE, HB_ERR_ARGS_BASEPARAMS );

      if( pSubst != NULL )
         hb_itemReturnRelease( pSubst );
      else
         hb_retc_null();
   }
}