/*
 * $Id$
 */

/*
 * Harbour Project source code:
 *   CHARRELA() and CHARRELREP() CT3 string functions
 *
 * 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"


/*  $DOC$
 *  $FUNCNAME$
 *      CHARRELA()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      Character relation of two strings
 *  $SYNTAX$
 *      CHARRELA (<cStringToMatch1>, <cString1>,
 *                <cStringToMatch2>, <cString2>) -> nPosition
 *  $ARGUMENTS$
 *  $RETURNS$
 *  $DESCRIPTION$
 *      TODO: add documentation
 *  $EXAMPLES$
 *  $TESTS$
 *  $STATUS$
 *      Started
 *  $COMPLIANCE$
 *      CHARRELA() is compatible with CT3's CHARRELA().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is relation.c, library is libct.
 *  $SEEALSO$
 *      CHARRELREP()
 *  $END$
 */

HB_FUNC( CHARRELA )
{
   if( ISCHAR( 1 ) && ISCHAR( 2 ) && ISCHAR( 3 ) && ISCHAR( 4 ) )
   {
      char *pcStringToMatch1 = hb_parc( 1 );
      size_t sStrToMatchLen1 = hb_parclen( 1 );
      char *pcString1 = hb_parc( 2 );
      size_t sStrLen1 = hb_parclen( 2 );
      char *pcStringToMatch2 = hb_parc( 3 );
      size_t sStrToMatchLen2 = hb_parclen( 3 );
      char *pcString2 = hb_parc( 4 );
      size_t sStrLen2 = hb_parclen( 4 );

      char *pc1, *pc2;
      size_t sOffset1, sOffset2;
      size_t sMatchStrLen;

      /* check for empty strings */
      if( ( sStrToMatchLen1 == 0 ) || ( sStrToMatchLen2 == 0 ) )
      {
         hb_retni( 0 );
         return;
      }

      sOffset1 = 0;
      sOffset2 = 0;

      /* NOTE: this algorithm is not the best since the search that gave
         the larger relative position in the step before is repeated;
         try a search algorithm alternating between both strings */
      while( sOffset1 < sStrLen1 && sOffset2 < sStrLen2 )
      {
         pc1 = ct_at_exact_forward( pcStringToMatch1, sStrToMatchLen1,
                                    pcString1 + sOffset1, sStrLen1 - sOffset1, &sMatchStrLen );
         pc2 = ct_at_exact_forward( pcStringToMatch2, sStrToMatchLen2,
                                    pcString2 + sOffset2, sStrLen2 - sOffset2, &sMatchStrLen );
         if( pc1 != NULL && pc2 != NULL )
         {
            if( pc1 - pcString1 == pc2 - pcString2 )
            {
               /* correlation found */
               hb_retnl( ( pc1 - pcString1 ) + 1 );
               return;
            }
            else
            {
               if( pc1 - pcString1 > pc2 - pcString2 )
                  sOffset1 = sOffset2 = pc1 - pcString1;
               else
                  sOffset1 = sOffset2 = pc2 - pcString2;
            }
         }
         else
         {
            sOffset1 = sOffset2 = sStrLen1 < sStrLen2 ? sStrLen1 : sStrLen2;
         }
      }

      hb_retni( 0 );
   }
   else  /* ISCHAR( 1 ) && ISCHAR( 2 ) && ISCHAR( 3 ) && ISCHAR( 4 ) */
   {
      PHB_ITEM pSubst = NULL;
      int iArgErrorMode = ct_getargerrormode();

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

      if( pSubst != NULL )
         hb_itemReturnRelease( pSubst );
      else
         hb_retni( 0 );
   }
}


/*  $DOC$
 *  $FUNCNAME$
 *      CHARRELREP()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      Relation dependant character replacement 
 *  $SYNTAX$
 *      CHARRELREP (<cStringToMatch1>, <cString1>,
 *                  <cStringToMatch2>, <[@]cString2>,
 *                  <cReplacement>) -> cString
 *  $ARGUMENTS$
 *  $RETURNS$
 *  $DESCRIPTION$
 *      TODO: add documentation
 *  $EXAMPLES$
 *  $TESTS$
 *  $STATUS$
 *      Started
 *  $COMPLIANCE$
 *      CHARRELREP() is compatible with CT3's CHARRELREP().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is relation.c, library is libct.
 *  $SEEALSO$
 *      CHARRELA(),CSETREF()
 *  $END$
 */

HB_FUNC( CHARRELREP )
{
   int iNoRet;

   iNoRet = ct_getref() && ISBYREF( 4 );

   if( ISCHAR( 1 ) && ISCHAR( 2 ) && ISCHAR( 3 ) &&
       ISCHAR( 4 ) && ISCHAR( 5 ) )
   {
      char *pcStringToMatch1 = hb_parc( 1 );
      size_t sStrToMatchLen1 = hb_parclen( 1 );
      char *pcString1 = hb_parc( 2 );
      size_t sStrLen1 = hb_parclen( 2 );
      char *pcStringToMatch2 = hb_parc( 3 );
      size_t sStrToMatchLen2 = hb_parclen( 3 );
      char *pcString2 = hb_parc( 4 );
      size_t sStrLen2 = hb_parclen( 4 );
      char *pcReplace = hb_parc( 5 );
      size_t sReplaceLen = hb_parclen( 5 );
      char *pcRet;
      char *pc1, *pc2;
      size_t sOffset1, sOffset2;
      size_t sMatchStrLen;

      /* check for empty strings */
      if( sStrToMatchLen1 == 0 ||
          sStrToMatchLen2 == 0 || sReplaceLen == 0 || sStrLen2 == 0 )
      {
         if( iNoRet )
            hb_ret();
         else
            hb_retclen( pcString2, sStrLen2 );
         return;
      }

      pcRet = ( char * ) hb_xgrab( sStrLen2 + 1 );
      hb_xmemcpy( pcRet, pcString2, sStrLen2 );

      sOffset1 = 0;
      sOffset2 = 0;

      /* NOTE: this algorithm is not the best since the search that gave
         the larger relative position in the step before is repeated;
         try a search algorithm alternating between both strings */
      while( ( sOffset1 < sStrLen1 ) && ( sOffset2 < sStrLen2 ) )
      {
         pc1 = ct_at_exact_forward( pcStringToMatch1, sStrToMatchLen1,
                                    pcString1 + sOffset1, sStrLen1 - sOffset1,
                                    &sMatchStrLen );
         pc2 = ct_at_exact_forward( pcStringToMatch2, sStrToMatchLen2,
                                    pcString2 + sOffset2, sStrLen2 - sOffset2,
                                    &sMatchStrLen );
         if( pc1 != NULL && pc2 != NULL )
         {
            if( pc1 - pcString1 == pc2 - pcString2 )
            {
               /* correlation found -> start replacement */
               size_t sCurr;

               for( sCurr = 1; sCurr <= sStrToMatchLen1; sCurr++ )
               {
                  /* check if pcString2 is long enough */
                  if( ( pc2 - pcString2 ) + sCurr >= sStrLen2 )
                  {
                     size_t sStr2Offset, sReplOffset;

                     sStr2Offset = sStrToMatchLen2 < sCurr ? sStrToMatchLen2 : sCurr;
                     sReplOffset = sReplaceLen < sCurr ? sReplaceLen : sCurr;

                     /* do the characters in pcString2 and pcStrToMatch2 match ? */
                     if( *( pc2 + sCurr - 1 ) ==
                         *( pcStringToMatch2 + sStr2Offset - 1 ) )
                     {
                        *( pcRet + ( pc2 - pcString2 ) + sCurr - 1 ) =
                           *( pcReplace + sReplOffset - 1 );
                     }
                  }
               }
               sOffset1 = sOffset2 = ( pc1 - pcString1 ) + 1;
            }
            else
            {
               if( pc1 - pcString1 > pc2 - pcString2 )
                  sOffset1 = sOffset2 = pc1 - pcString1;
               else
                  sOffset1 = sOffset2 = pc2 - pcString2;
            }
         }
         else
         {
            sOffset1 = sOffset2 = sStrLen1 < sStrLen2 ? sStrLen1 : sStrLen2;
         }
      }

      if( ISBYREF( 4 ) )
      {
         hb_storclen( pcRet, sStrLen2, 4 );
      }

      if( iNoRet )
      {
         hb_xfree( pcRet );
         hb_ret();
      }
      else
      {
         hb_retclen_buffer( pcRet, sStrLen2 );
      }
   }
   else  /* ISCHAR( 1 ) && ISCHAR( 2 ) && ISCHAR( 3 ) &&
            ISCHAR( 4 ) && ISCHAR( 5 ) */
   {
      PHB_ITEM pSubst = NULL;
      int iArgErrorMode = ct_getargerrormode();

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

      if( pSubst != NULL )
         hb_itemReturnRelease( pSubst );
      else if( iNoRet )
         hb_ret();
      else
         hb_retc( NULL );
   }
}
