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|
/*
+----------------------------------------------------------------------+
| PHP Version 5 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2012 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Author: Bjørn Borud - Guardian Networks AS <borud@guardian.no> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include "php.h"
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include "php_string.h"
/* Simple soundex algorithm as described by Knuth in TAOCP, vol 3 */
/* {{{ proto string soundex(string str)
Calculate the soundex key of a string */
PHP_FUNCTION(soundex)
{
char *str;
int i, _small, str_len, code, last;
char soundex[4 + 1];
static char soundex_table[26] =
{0, /* A */
'1', /* B */
'2', /* C */
'3', /* D */
0, /* E */
'1', /* F */
'2', /* G */
0, /* H */
0, /* I */
'2', /* J */
'2', /* K */
'4', /* L */
'5', /* M */
'5', /* N */
0, /* O */
'1', /* P */
'2', /* Q */
'6', /* R */
'2', /* S */
'3', /* T */
0, /* U */
'1', /* V */
0, /* W */
'2', /* X */
0, /* Y */
'2'}; /* Z */
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) == FAILURE) {
return;
}
if (str_len == 0) {
RETURN_FALSE;
}
/* build soundex string */
last = -1;
for (i = 0, _small = 0; i < str_len && _small < 4; i++) {
/* convert chars to upper case and strip non-letter chars */
/* BUG: should also map here accented letters used in non */
/* English words or names (also found in English text!): */
/* esstsett, thorn, n-tilde, c-cedilla, s-caron, ... */
code = toupper((int)(unsigned char)str[i]);
if (code >= 'A' && code <= 'Z') {
if (_small == 0) {
/* remember first valid char */
soundex[_small++] = code;
last = soundex_table[code - 'A'];
}
else {
/* ignore sequences of consonants with same soundex */
/* code in trail, and vowels unless they separate */
/* consonant letters */
code = soundex_table[code - 'A'];
if (code != last) {
if (code != 0) {
soundex[_small++] = code;
}
last = code;
}
}
}
}
/* pad with '0' and terminate with 0 ;-) */
while (_small < 4) {
soundex[_small++] = '0';
}
soundex[_small] = '\0';
RETURN_STRINGL(soundex, _small, 1);
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 fdm=marker
* vim<600: sw=4 ts=4
*/
|
