/*
 * $Id$
 */

/*
 * Harbour Project source code: 
 *   CT3 string functions
 *     - CHARONE()
 *     - WORDONE()
 *
 * 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"


/* defines */
#define DO_CHARONE_CHARONE     0
#define DO_CHARONE_WORDONE     1

/* helper function for the *one functions */
static void do_charone( int iSwitch )
{
   char *pcString;
   size_t sStrLen;
   char *pcDeleteSet;
   size_t sDeleteSetLen;

   /* param check */
   if( ISCHAR( 1 ) )
   {
      if( ISCHAR( 2 ) )
      {
         pcString = hb_parc( 2 );
         sStrLen = ( size_t ) hb_parclen( 2 );
         pcDeleteSet = hb_parc( 1 );
         sDeleteSetLen = ( size_t ) hb_parclen( 1 );
      }
      else
      {
         pcString = hb_parc( 1 );
         sStrLen = ( size_t ) hb_parclen( 1 );
         pcDeleteSet = NULL;
         sDeleteSetLen = 0;
      }

      switch ( iSwitch )
      {
         case DO_CHARONE_CHARONE:
            if( sStrLen > 1 )
            {
               char *pcSub;
               char *pcRet;
               size_t sRetStrLen = 0;
               char cCurrent = *pcString;

               pcRet = ( char * ) hb_xgrab( sStrLen );
               /* copy first char */
               pcRet[sRetStrLen++] = cCurrent;
               for( pcSub = pcString + 1; pcSub < pcString + sStrLen; pcSub++ )
               {
                  if( *pcSub != cCurrent )
                  {
                     cCurrent = *pcSub;
                     pcRet[sRetStrLen++] = cCurrent;
                  }
                  else if( pcDeleteSet != NULL &&
                           !ct_at_exact_forward( pcDeleteSet, sDeleteSetLen,
                                                 pcSub, 1, NULL ) )
                  {
                     pcRet[sRetStrLen++] = cCurrent;
                  }
               }
               hb_retclen( pcRet, sRetStrLen );
               hb_xfree( pcRet );
            }
            else                /* if( sStrLen > 1 ) */
            {
               /* algorithm does nothing to 1-char-strings */
               hb_retclen( pcString, sStrLen );
            }
            break;

         case DO_CHARONE_WORDONE:
            if( sStrLen > 3 && sDeleteSetLen >= 2 )
            {
               char *pcSub;
               char *pcRet;
               size_t sRetStrLen = 0;
               char cCurrent1 = pcString[0];
               char cCurrent2 = pcString[1];

               pcRet = ( char * ) hb_xgrab( sStrLen );
               /* copy first double char */
               pcRet[sRetStrLen++] = cCurrent1;
               pcRet[sRetStrLen++] = cCurrent2;

               for( pcSub = pcString + 2; pcSub < pcString + sStrLen - 1; pcSub += 2 )
               {
                  if( !( pcSub[0] == cCurrent1 && pcSub[1] == cCurrent2 ) )
                  {
                     cCurrent1 = pcSub[0];
                     cCurrent2 = pcSub[1];
                     pcRet[sRetStrLen++] = cCurrent1;
                     pcRet[sRetStrLen++] = cCurrent2;
                  }
                  else if( pcDeleteSet != NULL )
                  {
                     char *pc = NULL;
                     char *pStart = pcDeleteSet;
                     size_t sLen = sDeleteSetLen;

                     while( sLen >= 2 &&
                            ( pc = ct_at_exact_forward( pStart, sLen, pcSub,
                                                        2, NULL ) ) != 0 &&
                            ( pc - pcDeleteSet ) % 2 == 1 )
                     {
                        pStart = pc + 1;
                        sLen = sDeleteSetLen - ( pStart - pcDeleteSet );
                     }
                     if( pc == NULL )
                     {
                        pcRet[sRetStrLen++] = cCurrent1;
                        pcRet[sRetStrLen++] = cCurrent2;
                     }
                  }
               }

               /* copy last character if string len is odd */
               if( sStrLen & 1 )
               {
                  pcRet[sRetStrLen++] = pcString[sStrLen - 1];
               }
               hb_retclen( pcRet, sRetStrLen );
               hb_xfree( pcRet );
            }
            else                /* if( sStrLen > 3 ) */
            {
               /* algorithm does nothing to 3-char-strings */
               hb_retclen( pcString, sStrLen );
            }
            break;
      }  /* switch( iSwitch ) */
   }
   else  /* if( ISCHAR( 1 ) ) */
   {
      PHB_ITEM pSubst = NULL;
      int iArgErrorMode = ct_getargerrormode();

      if( iArgErrorMode != CT_ARGERR_IGNORE )
         pSubst = ct_error_subst( ( USHORT ) iArgErrorMode, EG_ARG,
                                  iSwitch == DO_CHARONE_CHARONE ?
                                  CT_ERROR_CHARONE : CT_ERROR_WORDONE,
                                  NULL, HB_ERR_FUNCNAME, 0, EF_CANSUBSTITUTE,
                                  HB_ERR_ARGS_BASEPARAMS );
      if( pSubst != NULL )
         hb_itemReturnRelease( pSubst );
      else
         hb_retc( NULL );
   }
}


/*  $DOC$
 *  $FUNCNAME$
 *      CHARONE()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      Reduce multiple occurences of a character to one
 *  $SYNTAX$
 *      CHARONE ([<cCharactersToReduce>,] <cString>) -> cReducedString
 *  $ARGUMENTS$
 *      [<cCharactersToReduce>]    specifies the characters the multiple
 *                                 occurences of which should be reduced to one
 *                                 Default: All characters.
 *      <cString>                  specifies the processed string
 *  $RETURNS$
 *      <cReducedString>           the string with the reduced occurences
 *  $DESCRIPTION$
 *      The CHARONE() function reduces multiple occurences of characters in
 *      <cString> to a single one. It is important to note that the multiple
 *      occurences must occur directly one behind the other. This behaviour is
 *      is in contrast to the CHARLIST() function. 
 *  $EXAMPLES$
 *      ? CHARONE("122333a123")      // "123a123"
 *      ? CHARONE("A  B  CCCD")      // "A B CD"
 *      ? CHARONE(" ", "A  B  A  B") // "A B A B"
 *      ? CHARONE("o", "122oooB12o") // "122oB12o"
 *  $TESTS$
 *      CHARONE("122333a123")      == "123a123"
 *      CHARONE("A  B  CCCD")      == "A B CD"
 *      CHARONE(" ", "A  B  A  B") == "A B A B"
 *      CHARONE("o", "122oooB12o") == "122oB12o"
 *  $STATUS$
 *      Ready
 *  $COMPLIANCE$
 *      CHARONE() is compatible with CT3's CHARONE().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is charone.c, library is ct3.
 *  $SEEALSO$
 *      CHARREM()   WORDONE()
 *  $END$
 */

HB_FUNC( CHARONE )
{
   do_charone( DO_CHARONE_CHARONE );
}


/*  $DOC$
 *  $FUNCNAME$
 *      WORDONE()
 *  $CATEGORY$
 *      CT3 string functions
 *  $ONELINER$
 *      Reduce multiple occurences of a double character to one
 *  $SYNTAX$
 *      WORDONE ([<cDoubleCharactersToReduce>,] <cString>) -> cReducedString
 *  $ARGUMENTS$
 *      [<cDoubleCharactersToReduce>]  specifies the double characters the multiple
 *                                     occurences of which should be reduced to one
 *                                     Default: All characters.
 *      <cString>                      specifies the processed string
 *  $RETURNS$
 *      <cReducedString>               the string with the reduced occurences
 *  $DESCRIPTION$
 *      The WORDONE() function reduces multiple occurences of double characters in
 *      <cString> to a single one. It is important to note that the multiple
 *      occurences must occur directly one behind the other.
 *  $EXAMPLES$
 *      ? WORDONE("12ABAB12")       // "12AB12"
 *      ? WORDONE("1AAAA2")         // "1AAAA2"
 *      ? WORDONE("12", "1212ABAB") // "12ABAB"
 *  $TESTS$
 *      WORDONE("12ABAB12")       == "12AB12"
 *      WORDONE("1AAAA2")         == "1AAAA2"
 *      WORDONE("12", "1212ABAB") == "12ABAB"
 *  $STATUS$
 *      Ready
 *  $COMPLIANCE$
 *      WORDONE() is compatible with CT3's WORDONE().
 *  $PLATFORMS$
 *      All
 *  $FILES$
 *      Source is charone.c, library is ct3.
 *  $SEEALSO$
 *      CHARONE()   CHARREM()
 *  $END$
 */

HB_FUNC( WORDONE )
{
   do_charone( DO_CHARONE_WORDONE );
}
