/*
 * $Id$
 */

/*
 * Harbour Project source code:
 *   WORDTOCHAR() CT3 string function
 *
 * Copyright 2001 IntTec GmbH, Neunlindenstr 32, 79106 Freiburg, Germany
 *        Author: Martin Vogel <vogel@inttec.de>
 *
 * 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, 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.  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"


/*  $DOC$
 *  $FUNCNAME$
 *      WORDTOCHAR()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      Replace double with single characters
 *  $SYNTAX$
 *      WORDTOCHAR (<cDoubleCharacterSearchString>, <cString>,
 *                  <cSingleCharacterReplaceString>) -> cString
 *  $ARGUMENTS$
 *  $RETURNS$
 *  $DESCRIPTION$
 *      TODO: add documentation
 *  $EXAMPLES$
 *  $TESTS$
 *  $STATUS$
 *      Started
 *  $COMPLIANCE$
 *      WORDTOCHAR() is compatible with CT3's WORDTOCHAR().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is wordtoch.c, library is libct.
 *  $SEEALSO$
 *      CSETATMUPA(),CHARREPL(),WORDREPL()
 *  $END$
 */

HB_FUNC( WORDTOCHAR )
{
   int iMultiPass;
   size_t sSearchLen, sStrLen, sReplaceLen;

   iMultiPass = ct_getatmupa();

   /* param check */
   if( ( sSearchLen = ( size_t ) hb_parclen( 1 ) ) / 2 > 0 &&
       ( sStrLen = ( size_t ) hb_parclen( 2 ) ) / 2 > 0 &&
       ( sReplaceLen = ( size_t ) hb_parclen( 3 ) ) > 0 )
   {

      /* get parameters */
      char *pcSearch = ( char * ) hb_parc( 1 );
      char *pcString = ( char * ) hb_parc( 2 );
      char *pcReplace = ( char * ) hb_parc( 3 );
      char *pcRet;
      size_t sRetIndex, sIndex;
      int iNoReplace;

      pcRet = ( char * ) hb_xgrab( sStrLen );
      sRetIndex = 0;
      sIndex = 0;
      iNoReplace = 0;

      *pcRet = *pcString;       /* copy first char */

      do
      {
         size_t sMatchStrLen;
         char *pc;
         size_t sReplIndex;

         *( pcRet + sRetIndex + 1 ) = *( pcString + sIndex + 1 );

         if( !iNoReplace &&
             ( ( pc = ct_at_exact_forward( pcSearch, sSearchLen,
                                           pcRet + sRetIndex, 2,
                                           &sMatchStrLen ) ) != NULL ) &&
             ( ( ( sReplIndex = ( pc - pcSearch ) ) & 1 ) != 1 ) )
         {
            sReplIndex /= 2;
            if( sReplIndex >= sReplaceLen )
               sReplIndex = sReplaceLen - 1;

            *( pcRet + sRetIndex ) = *( pcReplace + sReplIndex );

            if( !iMultiPass )
               iNoReplace = 1;  /* just copy next char without searching & replacing */
         }
         else
         {
            iNoReplace = 0;
            sRetIndex++;
         }
         sIndex++;
      }
      while( sIndex < sStrLen - 1 );

      /* return string */
      hb_retclen( pcRet, sRetIndex + 1 );
      hb_xfree( pcRet );
   }
   else  /* ( sSearchLen = ( size_t ) hb_parclen( 1 ) ) / 2 > 0 &&
            ( sStrLen = ( size_t ) hb_parclen( 2 ) ) / 2 > 0 &&
            ( sReplaceLen = ( size_t ) hb_parclen( 3 ) ) > 0 */
   {
      PHB_ITEM pSubst = NULL;
      int iArgErrorMode = ct_getargerrormode();

      if( iArgErrorMode != CT_ARGERR_IGNORE )
      {
         pSubst = ct_error_subst( ( USHORT ) iArgErrorMode, EG_ARG,
                                  CT_ERROR_WORDTOCHAR, NULL, "WORDTOCHAR", 0,
                                  EF_CANSUBSTITUTE, HB_ERR_ARGS_BASEPARAMS );
      }

      if( pSubst != NULL )
         hb_itemReturnRelease( pSubst );
      else if( ISCHAR( 2 ) )
         hb_retclen( hb_parc( 2 ), hb_parclen( 2 ) );
      else
         hb_retc( NULL );
   }
}
