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	adcroft	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			}