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/* text.c -- Text manipulation routines for Libmaa
* Created: Wed Apr 24 14:51:51 1996 by r.faith@ieee.org
* Revised: Sun Mar 9 22:28:33 1997 by faith@cs.unc.edu
* Copyright 1996 Rickard E. Faith (r.faith@ieee.org)
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library General Public License as published
* by the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: text.c,v 1.2 1997/03/10 21:39:45 faith Exp $
*
*/
#include <ctype.h>
#include "maaP.h"
/* \doc Given a string, return (in a |static| buffer), the Soundex value
for the string.
The basic algorithm for the soundex routine is from Donald
E. Knuth's THE ART OF COMPUTER PROGRAMMING, Volume 3: Sorting and
Searching (Addison-Wesley Publishing Co., 1973, pages 391 and 392).
Knuth notes that the method was originally described by Margaret
K. Odell and Robert C. Russell [US Patents 1261167 (1918) and 1435663
(1922)]. */
const char *txt_soundex( const char *string )
{
static char result[5];
char *pt = result;
int upper_case;
/* abcdefghijklmnopqrstuvwxyz */
static char map[] = "01230120022455012623010202";
char previous = 0;
char transform;
int i;
strcpy( result, "Z000" );
for (i = 0; *string && i < 4; ++string) {
if (isalpha( *string )) {
upper_case = toupper( *string );
transform = map[ upper_case - 'A' ];
if (!i) {
*pt++ = upper_case;
++i;
} else {
if (transform != '0' && transform != previous) {
*pt++ = transform;
++i;
}
}
previous = transform;
}
}
return result;
}
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