swish-e/src/soundex.c

/*
** Copyright (C) 1999 OpenSA Project
**
 * Reference: Adapted from Knuth, D.E. (1973) The art of computer programming;
 *    Volume 3: Sorting and searching.  Addison-Wesley Publishing Company:
 *    Reading, Mass. Page 392.
 *
 * 1. Retain the first letter of the name, and drop all occurrences of
 *    a, e, h, i, o, u, w, y in other positions.
 *
 * 2. Assign the following numbers to the remaining letters after the first:
 *      b, f, p, v -> 1                         l -> 4
 *      c, g, j, k, q, s, x, z -> 2             m, n -> 5
 *      d, t -> 3                               r -> 6
 *
 * 3. If two or more letters with the same code were adjacent in the original
 *    name (before step 1), omit all but the first.
 *
 * 4. Convert to the form ``letter, digit, digit, digit'' by adding trailing
 *    zeros (if there are less than three digits), or by dropping rightmost
 *    digits (if there are more than three).
 *
 * The examples given in the book are:
 *
 *      Euler, Ellery           E460
 *      Gauss, Ghosh            G200
 *      Hilbert, Heilbronn      H416
 *      Knuth, Kant             K530
 *      Lloyd, Ladd             L300
 *      Lukasiewicz, Lissajous  L222
 *
 * Most algorithms fail in two ways:
 *  1. they omit adjacent letters with the same code AFTER step 1, not before.
 *  2. they do not omit adjacent letters with the same code at the beginning
 *     of the name.
 *
 */

#include "swish.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "soundex.h"

int soundex(word)
   char *word;  /* in/out: Target word  */
   {
        /* Misc Stuff  */
        char u, l ;
        int i, j, n;
        /* Resultant Sound Code  */
        char soundCode[5] = "0000\0";
        /* Group Number Lookup Table  */
        static char soundTable[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  */
#ifdef _DEBUG
        /* Debug to console  */
        printf("# %15s: %s ", "soundex.c", word);
#endif

        /* Make sure it actually starts with a letter  */
        if(!isalpha((int)((unsigned char)word[0]))) return soundXit();
#ifdef _DEBUG
        /* Debug to console  */
        printf("isalpha, ");
#endif
        
        /* Get string length and make sure its at least 3 characters  */
        if((n = (int)strlen(word)) < 3) return soundXit();
#ifdef _DEBUG
        /* Debug to console  */
        printf("=>3, ");
#endif

        /* Convert chars to lower case and strip non-letter chars  */
        j = 0;
        for (i = 0; i < n; i++) {
                u = tolower((unsigned char)word[i]);
                if ((u > 96) && (u < 123)) {
                         word[j] = u;
                        j++;
                }
        }

        /* terminate string  */
         word[j] = 0;

        /* String length again  */
        n = strlen(word);

        soundCode[0] = word[0];

        /* remember first char  */
        l = soundTable[((word[0]) - 97)];

        j = 1;

        /* build soundex string  */
        for (i = 1; i < n && j < 4; i++) {
                u = soundTable[((word[i]) - 97)];

                if (u != l) {
                        if (u != 0) {
                                soundCode[(int) j++] = u;
                        }
                        l = u;
                }
        }
        strcpy(word, soundCode);
#ifdef _DEBUG
        /* Debug to console  */
        printf("-> \"%s\"\n", word);
#endif

        return(1);
}

int soundXit(void)
{
#ifdef _DEBUG
        printf("was left as is...\n");
#endif
        return(1);
}
1	/*
2	** Copyright (C) 1999 OpenSA Project
3	**
4	* Reference: Adapted from Knuth, D.E. (1973) The art of computer programming;
5	* Volume 3: Sorting and searching. Addison-Wesley Publishing Company:
6	* Reading, Mass. Page 392.
7	*
8	* 1. Retain the first letter of the name, and drop all occurrences of
9	* a, e, h, i, o, u, w, y in other positions.
10	*
11	* 2. Assign the following numbers to the remaining letters after the first:
12	* b, f, p, v -> 1 l -> 4
13	* c, g, j, k, q, s, x, z -> 2 m, n -> 5
14	* d, t -> 3 r -> 6
15	*
16	* 3. If two or more letters with the same code were adjacent in the original
17	* name (before step 1), omit all but the first.
18	*
19	* 4. Convert to the form ``letter, digit, digit, digit'' by adding trailing
20	* zeros (if there are less than three digits), or by dropping rightmost
21	* digits (if there are more than three).
22	*
23	* The examples given in the book are:
24	*
25	* Euler, Ellery E460
26	* Gauss, Ghosh G200
27	* Hilbert, Heilbronn H416
28	* Knuth, Kant K530
29	* Lloyd, Ladd L300
30	* Lukasiewicz, Lissajous L222
31	*
32	* Most algorithms fail in two ways:
33	* 1. they omit adjacent letters with the same code AFTER step 1, not before.
34	* 2. they do not omit adjacent letters with the same code at the beginning
35	* of the name.
36	*
37	*/
38
39	#include "swish.h"
40	#include <stdio.h>
41	#include <stdlib.h>
42	#include <string.h>
43	#include <ctype.h>
44
45	#include "soundex.h"
46
47	int soundex(word)
48	char word; / in/out: Target word */
49	{
50	/* Misc Stuff */
51	char u, l ;
52	int i, j, n;
53	/* Resultant Sound Code */
54	char soundCode[5] = "0000\0";
55	/* Group Number Lookup Table */
56	static char soundTable[26] =
57	{0, /* A */
58	'1', /* B */
59	'2', /* C */
60	'3', /* D */
61	0, /* E */
62	'1', /* F */
63	'2', /* G */
64	0, /* H */
65	0, /* I */
66	'2', /* J */
67	'2', /* K */
68	'4', /* L */
69	'5', /* M */
70	'5', /* N */
71	0, /* O */
72	'1', /* P */
73	'2', /* Q */
74	'6', /* R */
75	'2', /* S */
76	'3', /* T */
77	0, /* U */
78	'1', /* V */
79	0, /* W */
80	'2', /* X */
81	0, /* Y */
82	'2'}; /* Z */
83	#ifdef _DEBUG
84	/* Debug to console */
85	printf("# %15s: %s ", "soundex.c", word);
86	#endif
87
88	/* Make sure it actually starts with a letter */
89	if(!isalpha((int)((unsigned char)word[0]))) return soundXit();
90	#ifdef _DEBUG
91	/* Debug to console */
92	printf("isalpha, ");
93	#endif
94
95	/* Get string length and make sure its at least 3 characters */
96	if((n = (int)strlen(word)) < 3) return soundXit();
97	#ifdef _DEBUG
98	/* Debug to console */
99	printf("=>3, ");
100	#endif
101
102	/* Convert chars to lower case and strip non-letter chars */
103	j = 0;
104	for (i = 0; i < n; i++) {
105	u = tolower((unsigned char)word[i]);
106	if ((u > 96) && (u < 123)) {
107	word[j] = u;
108	j++;
109	}
110	}
111
112	/* terminate string */
113	word[j] = 0;
114
115	/* String length again */
116	n = strlen(word);
117
118	soundCode[0] = word[0];
119
120	/* remember first char */
121	l = soundTable[((word[0]) - 97)];
122
123	j = 1;
124
125	/* build soundex string */
126	for (i = 1; i < n && j < 4; i++) {
127	u = soundTable[((word[i]) - 97)];
128
129	if (u != l) {
130	if (u != 0) {
131	soundCode[(int) j++] = u;
132	}
133	l = u;
134	}
135	}
136	strcpy(word, soundCode);
137	#ifdef _DEBUG
138	/* Debug to console */
139	printf("-> \"%s\"\n", word);
140	#endif
141
142	return(1);
143	}
144
145	int soundXit(void)
146	{
147	#ifdef _DEBUG
148	printf("was left as is...\n");
149	#endif
150	return(1);
151	}