128 lines
3.6 KiB
C
128 lines
3.6 KiB
C
/*
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* $Id$
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*
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Harbour Project source code
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Copyright(C) 1999 by Jose Lalin.
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http://www.Harbour-Project.org/
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published
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by the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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The exception is that if you link the Harbour Runtime Library (HRL)
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and/or the Harbour Virtual Machine (HVM) with other files to produce
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an executable, this does not by itself cause the resulting executable
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to be covered by the GNU General Public License. Your use of that
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executable is in no way restricted on account of linking the HRL
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and/or HVM code into it.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA (or visit
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their web site at http://www.gnu.org/).
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You can contact me at: dezac@corevia.com
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*/
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/* $DOC$
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* $FUNCNAME$
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* DESCEND
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* $CATEGORY$
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*
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* $ONELINER$
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* Inverts an expression of string, logical, date or numeric type.
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* $SYNTAX$
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* DESCEND( <xExp> ) --> <xExpInverted>
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* $ARGUMENTS$
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* <xExp> is any valid expression.
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* $RETURNS$
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* Inverted value of the same type as passed.
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* $DESCRIPTION$
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* This function converts an expression in his inverted form. It is
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* useful to build descending indexes.
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* $EXAMPLES$
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* // Seek for Smith in a descending index
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* SEEK DESCEND( "SMITH" )
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* $TESTS$
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* DATA->( DBSEEK( DESCEND( "SMITH" ) ) )
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* will seek "SMITH" into a descending index.
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* $STATUS$
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* C
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* $COMPLIANCE$
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* DESCEND is fully CA-Clipper compliant.
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* $SEEALSO$
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* INDEX, SEEK
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* $END$
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*/
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#include "extend.h"
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#include "itemapi.h"
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#include "init.h"
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HARBOUR HB_DESCEND(void);
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HB_INIT_SYMBOLS_BEGIN( Descend__InitSymbols )
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{ "DESCEND", FS_PUBLIC, HB_DESCEND, 0 }
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HB_INIT_SYMBOLS_END( Descend__InitSymbols );
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#if ! defined(__GNUC__)
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#pragma Descend__InitSymbols
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#endif
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char * hb_strdescend( char * szText, ULONG ulLen )
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{
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if (!(ulLen == 1 && szText[0] == 0))
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{
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char *s;
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for( s = szText; ulLen--; ++s )
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*s = 256 - *s;
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}
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return szText;
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}
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HARBOUR HB_DESCEND( void )
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{
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if( hb_pcount() == 1 )
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{
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PHB_ITEM pItem = hb_param(1, IT_ANY );
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if( pItem )
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{
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if( IS_STRING( pItem ) )
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hb_retclen( hb_strdescend( pItem->item.asString.value, pItem->item.asString.length ), pItem->item.asString.length );
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else if( IS_DATE( pItem ) )
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hb_retnl( 5231808 - pItem->item.asDate.value );
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else if( IS_NUMERIC( pItem ) )
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{
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PHB_ITEM pReturn;
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double dValue;
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if ( IS_DOUBLE( pItem ) )
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dValue = (double)pItem->item.asDouble.value;
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else if( IS_INTEGER( pItem ) )
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dValue = (double)pItem->item.asInteger.value;
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else if( IS_LONG( pItem ) )
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dValue = pItem->item.asLong.value;
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pReturn = hb_itemPutND( NULL, -1 * dValue );
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hb_itemReturn( pReturn );
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hb_itemRelease( pReturn );
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/* It is dengerous to operate on the stack directly
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stack.Return.wDec = pItem->wDec;
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*/
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}
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else if( IS_LOGICAL( pItem ) )
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hb_retl( !pItem->item.asLogical.value );
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}
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}
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}
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