harbour-core/harbour/src/rtl/ati.c

/*
 * $Id$
 */

/*
 * Harbour Project source code:
 * HB_ATI() function
 *
 * Copyright 1999-2009 Viktor Szakats (harbour.01 syenar.hu)
 * Copyright 1999 Antonio Linares <alinares@fivetech.com>
 * 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.  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 "hbapi.h"
#include "hbapiitm.h"
#include "hbapierr.h"

static HB_SIZE hb_strAtI( const char * szSub, HB_SIZE nSubLen, const char * szText, HB_SIZE nLen )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_strAt(%s, %" HB_PFS "u, %s, %" HB_PFS "u)", szSub, nSubLen, szText, nLen));

   if( nSubLen > 0 && nLen >= nSubLen )
   {
      HB_SIZE nPos = 0;
      HB_SIZE nSubPos = 0;

      while( nPos < nLen && nSubPos < nSubLen )
      {
         if( hb_charLower( szText[ nPos ] ) == hb_charLower( szSub[ nSubPos ] ) )
         {
            ++nSubPos;
            ++nPos;
         }
         else if( nSubPos )
         {
            /* Go back to the first character after the first match,
               or else tests like "22345" $ "012223456789" will fail. */
            nPos -= ( nSubPos - 1 );
            nSubPos = 0;
         }
         else
            ++nPos;
      }

      return ( nSubPos < nSubLen ) ? 0 : ( nPos - nSubLen + 1 );
   }
   else
      return 0;
}

HB_FUNC( HB_ATI )
{
   PHB_ITEM pSub = hb_param( 1, HB_IT_STRING );
   PHB_ITEM pText = hb_param( 2, HB_IT_STRING );

   if( pText && pSub )
   {
      HB_SIZE nTextLength = hb_itemGetCLen( pText );
      HB_SIZE nStart = hb_parnsdef( 3, 1 );
      HB_SIZE nEnd = hb_parnsdef( 4, nTextLength );
      HB_SIZE nPos;

      if( nStart > nTextLength || nEnd < nStart )
         hb_retns( 0 );
      else
      {
         if( nEnd > nTextLength )
            nEnd = nTextLength;

         nPos = hb_strAtI( hb_itemGetCPtr( pSub ), hb_itemGetCLen( pSub ),
                           hb_itemGetCPtr( pText ) + nStart - 1, nEnd - nStart + 1 );

         if( nPos > 0 )
            nPos += ( nStart - 1 );

         hb_retns( nPos );
      }
   }
   else
      hb_errRT_BASE_SubstR( EG_ARG, 1108, NULL, HB_ERR_FUNCNAME, HB_ERR_ARGS_BASEPARAMS );
}