1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 5 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1997-2013 The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Author: Bj�rn Borud - Guardian Networks AS <borud@guardian.no> |
16 +----------------------------------------------------------------------+
17 */
18 /* $Id$ */
19
20 #include "php.h"
21 #include <stdlib.h>
22 #include <errno.h>
23 #include <ctype.h>
24 #include "php_string.h"
25
26 /* Simple soundex algorithm as described by Knuth in TAOCP, vol 3 */
27 /* {{{ proto string soundex(string str)
28 Calculate the soundex key of a string */
PHP_FUNCTION(soundex)29 PHP_FUNCTION(soundex)
30 {
31 char *str;
32 int i, _small, str_len, code, last;
33 char soundex[4 + 1];
34
35 static char soundex_table[26] =
36 {0, /* A */
37 '1', /* B */
38 '2', /* C */
39 '3', /* D */
40 0, /* E */
41 '1', /* F */
42 '2', /* G */
43 0, /* H */
44 0, /* I */
45 '2', /* J */
46 '2', /* K */
47 '4', /* L */
48 '5', /* M */
49 '5', /* N */
50 0, /* O */
51 '1', /* P */
52 '2', /* Q */
53 '6', /* R */
54 '2', /* S */
55 '3', /* T */
56 0, /* U */
57 '1', /* V */
58 0, /* W */
59 '2', /* X */
60 0, /* Y */
61 '2'}; /* Z */
62
63 if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) == FAILURE) {
64 return;
65 }
66 if (str_len == 0) {
67 RETURN_FALSE;
68 }
69
70 /* build soundex string */
71 last = -1;
72 for (i = 0, _small = 0; i < str_len && _small < 4; i++) {
73 /* convert chars to upper case and strip non-letter chars */
74 /* BUG: should also map here accented letters used in non */
75 /* English words or names (also found in English text!): */
76 /* esstsett, thorn, n-tilde, c-cedilla, s-caron, ... */
77 code = toupper((int)(unsigned char)str[i]);
78 if (code >= 'A' && code <= 'Z') {
79 if (_small == 0) {
80 /* remember first valid char */
81 soundex[_small++] = code;
82 last = soundex_table[code - 'A'];
83 }
84 else {
85 /* ignore sequences of consonants with same soundex */
86 /* code in trail, and vowels unless they separate */
87 /* consonant letters */
88 code = soundex_table[code - 'A'];
89 if (code != last) {
90 if (code != 0) {
91 soundex[_small++] = code;
92 }
93 last = code;
94 }
95 }
96 }
97 }
98 /* pad with '0' and terminate with 0 ;-) */
99 while (_small < 4) {
100 soundex[_small++] = '0';
101 }
102 soundex[_small] = '\0';
103
104 RETURN_STRINGL(soundex, _small, 1);
105 }
106 /* }}} */
107
108 /*
109 * Local variables:
110 * tab-width: 4
111 * c-basic-offset: 4
112 * End:
113 * vim600: sw=4 ts=4 fdm=marker
114 * vim<600: sw=4 ts=4
115 */
116
