Files
harbour-core/harbour/source/rtl/soundex.c

114 lines
4.0 KiB
C

/*
* $Id$
*/
/*
* Harbour Project source code:
* SOUNDEX() function
*
* Copyright 1999-2001 Viktor Szakats <viktor.szakats@syenar.hu>
* 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 <ctype.h>
#include "hbapi.h"
#include "hbapiitm.h"
#define SOUNDEX_LEN_MAX 4
HB_FUNC( SOUNDEX )
{
PHB_ITEM pString = hb_param( 1, HB_IT_STRING );
char szResult[ SOUNDEX_LEN_MAX + 1 ];
/* NOTE: The result will always be a zero terminated string without any
embedded zeros and special characters. [vszakats] */
memset( szResult, '0', SOUNDEX_LEN_MAX );
szResult[ SOUNDEX_LEN_MAX ] = '\0';
if( pString )
{
char * pszString = hb_itemGetCPtr( pString );
ULONG ulLen = hb_itemGetCLen( pString );
ULONG nPos = 0;
ULONG nResultPos = 0;
char cCharPrev = '0';
while( nPos < ulLen && nResultPos < SOUNDEX_LEN_MAX )
{
char cChar = pszString[ nPos ];
/* NOTE: Intentionally not using toupper()/isalpha() to be 100%
Clipper compatible here, these ANSI C functions may behave
differently for accented and national characters. It's also
faster this way. [vszakats] */
/* Convert to uppercase: toupper() */
if( cChar >= 'a' && cChar <= 'z' )
cChar -= ( 'a' - 'A' );
/* Check if isalpha() */
if( cChar >= 'A' && cChar <= 'Z' )
{
static const char s_szTable[] = "01230120022455012623010202"; /* NOTE: SoundEx result codes for letters from "A" to "Z" */
/* "ABCDEFGHIJKLMNOPQRSTUVWXYZ" */
char cCharConverted = ( ( cChar - 'A' ) > ( sizeof( s_szTable ) - 1 ) ) ? '9' : s_szTable[ cChar - 'A' ];
if( nResultPos == 0 )
szResult[ nResultPos++ ] = cChar;
else if( cCharConverted != '0' && cCharConverted != cCharPrev )
szResult[ nResultPos++ ] = cCharConverted;
cCharPrev = cCharConverted;
}
nPos++;
}
}
hb_retc( szResult );
}