xref: /freebsd/usr.bin/locate/bigram/locate.bigram.c (revision 370021810ab49e070cc0bf153a3c629a73ef357b)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * James A. Woods.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifndef lint
38 static char copyright[] =
39 "@(#) Copyright (c) 1989, 1993\n\
40 	The Regents of the University of California.  All rights reserved.\n";
41 #endif /* not lint */
42 
43 #ifndef lint
44 static char sccsid[] = "@(#)locate.bigram.c	8.1 (Berkeley) 6/6/93";
45 #endif /* not lint */
46 
47 /*
48  *  bigram < text > bigrams
49  *
50  * List bigrams for 'updatedb' script.
51  * Use 'code' to encode a file using this output.
52  */
53 
54 #include <stdio.h>
55 #include <sys/param.h>			/* for MAXPATHLEN */
56 #include <string.h>			/* memchr */
57 #include "locate.h"
58 
59 u_char buf1[MAXPATHLEN] = " ";
60 u_char buf2[MAXPATHLEN];
61 unsigned int bigram[UCHAR_MAX][UCHAR_MAX];
62 
63 
64 void main ( )
65 {
66   	register u_char *cp;
67 	register u_char *oldpath = buf1, *path = buf2;
68 	register int i, j;
69 
70 	/* init bigram buffer */
71 	for (i = 0; i < UCHAR_MAX; i++)
72 	    	for (j = 0; j < UCHAR_MAX; j++)
73 			bigram[i][j] = 0;
74 
75      	while ( fgets ( path, sizeof(buf2), stdin ) != NULL ) {
76 
77 	    	/* skip empty lines */
78 		if (*path == '\n')
79 			continue;
80 
81 		/* Squelch characters that would botch the decoding. */
82 		for (cp = path; *cp != NULL; cp++) {
83 			/* chop newline */
84 			if (*cp == '\n')
85 				*cp = NULL;
86 			/* range */
87 			else if (*cp < ASCII_MIN || *cp > ASCII_MAX)
88 				*cp = '?';
89 		}
90 
91 
92 		/* skip longest common prefix */
93 		for (cp = path; *cp == *oldpath && *cp; cp++, oldpath++);
94 
95 		/*
96 		 * output post-residue bigrams only
97 		 */
98 
99 		/* check later for boundary */
100 		while ( *cp != NULL && *(cp + 1) != NULL ) {
101 			bigram[*cp][*(cp+1)]++;
102 			cp += 2;
103 		}
104 
105 		if ( path == buf1 )		/* swap pointers */
106 			path = buf2, oldpath = buf1;
107 		else
108 			path = buf1, oldpath = buf2;
109    	}
110 
111 	/* output, boundary check */
112 	for (i = ASCII_MIN; i <= ASCII_MAX; i++)
113 		for (j = ASCII_MIN; j <= ASCII_MAX; j++)
114 			if (bigram[i][j] != 0)
115 				fprintf(stdout, "%4d %c%c\n",
116 					bigram[i][j], i, j);
117 }
118