/*
 * $Id$
 */

/*
 * Harbour Project source code:
 *   POSDIFF() and POSEQUAL() 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"


/*  $DOC$
 *  $FUNCNAME$
 *      POSDIFF()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      The left-most position there two string differ
 *  $SYNTAX$
 *      POSDIFF (<cString1>, <cString2>, [<nIgnore>]) -> nPosition
 *  $ARGUMENTS$
 *  $RETURNS$
 *  $DESCRIPTION$
 *      TODO: add documentation
 *  $EXAMPLES$
 *  $TESTS$
 *  $STATUS$
 *      Started
 *  $COMPLIANCE$
 *      POSDIFF() is compatible with CT3's POSDIFF().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is posdiff.c, library is libct.
 *  $SEEALSO$
 *      POSEQUAL()
 *  $END$
 */

HB_FUNC (POSDIFF)
{

  if (ISCHAR (1) && ISCHAR (2))
  {
    
    char *pcString1 = hb_parc (1);
    size_t sStrLen1 = hb_parclen (1);
    char *pcString2 = hb_parc (2);
    size_t sStrLen2 = hb_parclen (2);
    char *pc1, *pc2;

    size_t sIgnore;

    if (ISNUM (3))
      sIgnore = hb_parnl (3);
    else
      sIgnore = 0;

    if ((sIgnore > sStrLen1) || (sIgnore > sStrLen2))
    {
      int iArgErrorMode = ct_getargerrormode();
      if (iArgErrorMode != CT_ARGERR_IGNORE)
      {
        ct_error ((USHORT)iArgErrorMode, EG_ARG, CT_ERROR_POSDIFF,
                  NULL, "POSDIFF", 0, EF_CANDEFAULT, 3,
                  hb_paramError (1), hb_paramError (2),
                  hb_paramError (3));
      }

      hb_retnl (0);
      return;
    }
    
    if (sStrLen1 != sStrLen2)
    {
      hb_retnl ((sStrLen1 < sStrLen2 ? sStrLen1 : sStrLen2)+1);
      return;
    }
    
    pc1 = pcString1+sIgnore;
    pc2 = pcString2+sIgnore;

    while (pc1 < pcString1+sStrLen1)
    {
      if (*pc1 != *pc2)
      {
        hb_retnl ((pc1-pcString1)+1);
        return;
      }
      pc1++;
      pc2++;
    }

    hb_retnl (0);

  }
  else /* (ISCHAR (1) && ISCHAR (2)) */
  {
    PHB_ITEM pSubst = NULL;
    int iArgErrorMode = ct_getargerrormode();
    if (iArgErrorMode != CT_ARGERR_IGNORE)
    {
      pSubst = ct_error_subst ((USHORT)iArgErrorMode, EG_ARG, CT_ERROR_POSDIFF,
                               NULL, "POSDIFF", 0, EF_CANSUBSTITUTE, 3,
                               hb_paramError (1), hb_paramError (2), hb_paramError (3));
    }
    
    if (pSubst != NULL)
    {
      hb_itemReturn (pSubst);
      hb_itemRelease (pSubst);
    }
    else
    {
      if (ISCHAR (1) || ISCHAR (2))
        hb_retnl (1);
      else
        hb_retnl (0);
    }

  }

  return;

}


/*  $DOC$
 *  $FUNCNAME$
 *      POSEQUAL()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      The left-most position there two string begin to be equal
 *  $SYNTAX$
 *      POSEQUAL (<cString1>, <cString2>, [<nCompare>], [<nIgnore>]) -> nPosition
 *  $ARGUMENTS$
 *  $RETURNS$
 *  $DESCRIPTION$
 *      TODO: add documentation
 *  $EXAMPLES$
 *  $TESTS$
 *  $STATUS$
 *      Started
 *  $COMPLIANCE$
 *      POSEQUAL() is compatible with CT3's POSEQUAL().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is posdiff.c, library is libct.
 *  $SEEALSO$
 *      POSDIFF()
 *  $END$
 */

HB_FUNC (POSEQUAL)
{

  if (ISCHAR (1) && ISCHAR (2))
  {
    
    char *pcString1 = hb_parc (1);
    size_t sStrLen1 = hb_parclen (1);
    char *pcString2 = hb_parc (2);
    size_t sStrLen2 = hb_parclen (2);
    char *pc1, *pc2;

    size_t sIgnore, sCompare, sCompareCnt, sRet = 0;

    if (ISNUM (4))
      sIgnore = hb_parnl (4);
    else
      sIgnore = 0;

    if (ISNUM (3))
      sCompare = hb_parnl (3);
    else
      sCompare = (sStrLen1 < sStrLen2 ? sStrLen1 : sStrLen2)-sIgnore;

    if ((sCompare == 0) || (sIgnore > sStrLen1) || (sIgnore > sStrLen2))
    {
      int iArgErrorMode = ct_getargerrormode();
      if (iArgErrorMode != CT_ARGERR_IGNORE)
      {
        ct_error ((USHORT)iArgErrorMode, EG_ARG, CT_ERROR_POSEQUAL,
                  NULL, "POSEQUAL", 0, EF_CANDEFAULT, 4,
                  hb_paramError (1), hb_paramError (2),
                  hb_paramError (3), hb_paramError (4));
      }

      hb_retnl (0);
      return;
    }
    
    if ((sStrLen1 < (sCompare+sIgnore)) || (sStrLen2 < (sCompare+sIgnore)))
    {
      int iArgErrorMode = ct_getargerrormode();
      if (iArgErrorMode != CT_ARGERR_IGNORE)
      {
        ct_error ((USHORT)iArgErrorMode, EG_ARG, CT_ERROR_POSEQUAL,
                  NULL, "POSEQUAL", 0, EF_CANDEFAULT, 4,
                  hb_paramError (1), hb_paramError (2),
                  hb_paramError (3), hb_paramError (4));
      }

      hb_retnl (0);
      return;
    }
    
    pc1 = pcString1+sIgnore;
    pc2 = pcString2+sIgnore;
    sCompareCnt = 0;

    while (pc1 < pcString1+sStrLen1)
    {
      if (*pc1 == *pc2)
      {
        /* save possible return value */
        if (sCompareCnt == 0)
          sRet = pc1-pcString1+1;
        
        sCompareCnt++;
        if (sCompareCnt == sCompare)
        {
          hb_retnl (sRet);
          return;
        }
      }
      else
      {
        /* reset compare counter */
        sCompareCnt = 0;
      }
      pc1++;
      pc2++;
    }

    hb_retnl (0);

  }
  else /* (ISCHAR (1) && ISCHAR (2)) */
  {
    PHB_ITEM pSubst = NULL;
    int iArgErrorMode = ct_getargerrormode();
    if (iArgErrorMode != CT_ARGERR_IGNORE)
    {
      pSubst = ct_error_subst ((USHORT)iArgErrorMode, EG_ARG, CT_ERROR_POSEQUAL,
                               NULL, "POSEQUAL", 0, EF_CANSUBSTITUTE, 4,
                               hb_paramError (1), hb_paramError (2),
                               hb_paramError (3), hb_paramError (4));
    }
    
    if (pSubst != NULL)
    {
      hb_itemReturn (pSubst);
      hb_itemRelease (pSubst);
    }
    else
    {
      hb_retnl (0);
    }
  }

  return;

}