1 /* $NetBSD: locate.code.c,v 1.12 2019/10/13 19:39:15 christos Exp $ */
2
3 /*
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * James A. Woods.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #ifndef lint
37 __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
38 The Regents of the University of California. All rights reserved.");
39 #endif /* not lint */
40
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)locate.code.c 8.4 (Berkeley) 5/4/95";
44 #endif
45 __RCSID("$NetBSD: locate.code.c,v 1.12 2019/10/13 19:39:15 christos Exp $");
46 #endif /* not lint */
47
48 /*
49 * PURPOSE: sorted list compressor (works with a modified 'find'
50 * to encode/decode a filename database)
51 *
52 * USAGE: bigram < list > bigrams
53 * process bigrams (see updatedb) > common_bigrams
54 * code common_bigrams < list > squozen_list
55 *
56 * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1
57 * February/March 1983, p. 8). Output format is, per line, an
58 * offset differential count byte followed by a partially bigram-
59 * encoded ascii residue. A bigram is a two-character sequence,
60 * the first 128 most common of which are encoded in one byte.
61 *
62 * EXAMPLE: For simple front compression with no bigram encoding,
63 * if the input is... then the output is...
64 *
65 * /usr/src 0 /usr/src
66 * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c
67 * /usr/src/cmd/armadillo.c 14 armadillo.c
68 * /usr/tmp/zoo 5 tmp/zoo
69 *
70 * The codes are:
71 *
72 * 0-28 likeliest differential counts + offset to make nonnegative
73 * 30 switch code for out-of-range count to follow in next word
74 * 128-255 bigram codes (128 most common, as determined by 'updatedb')
75 * 32-127 single character (printable) ascii residue (ie, literal)
76 *
77 * SEE ALSO: updatedb.csh, bigram.c
78 *
79 * AUTHOR: James A. Woods, Informatics General Corp.,
80 * NASA Ames Research Center, 10/82
81 */
82
83 #include <sys/param.h>
84
85 #include <err.h>
86 #include <errno.h>
87 #include <stdio.h>
88 #include <stdlib.h>
89 #include <string.h>
90 #include <unistd.h>
91
92 #include "locate.h"
93
94 #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */
95
96 static char buf1[MAXPATHLEN] = " ";
97 static char buf2[MAXPATHLEN];
98 static char bigrams[BGBUFSIZE + 1] = { 0 };
99
100 static int bgindex(char *);
101 __dead static void usage(void);
102
103 int
main(int argc,char * argv[])104 main(int argc, char *argv[])
105 {
106 char *cp, *oldpath, *path;
107 int ch, code, count, diffcount, oldcount;
108
109 while ((ch = getopt(argc, argv, "")) != -1)
110 switch(ch) {
111 case '?':
112 default:
113 usage();
114 }
115 argc -= optind;
116 argv += optind;
117
118 if (argc != 1)
119 usage();
120
121 /* First copy bigram array to stdout. */
122 strncpy(bigrams, argv[0], BGBUFSIZE);
123 bigrams[BGBUFSIZE] = '\0';
124 if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE)
125 err(1, "stdout");
126
127 oldpath = buf1;
128 path = buf2;
129 oldcount = 0;
130 while (fgets(path, sizeof(buf2), stdin) != NULL) {
131 /* Truncate newline. */
132 cp = path + strlen(path) - 1;
133 if (cp > path && *cp == '\n')
134 *cp = '\0';
135
136 /* Squelch characters that would botch the decoding. */
137 for (cp = path; *cp != '\0'; cp++) {
138 *cp &= PARITY-1;
139 if (*cp <= SWITCH)
140 *cp = '?';
141 }
142
143 /* Skip longest common prefix. */
144 for (cp = path; *cp == *oldpath; cp++, oldpath++)
145 if (*oldpath == '\0')
146 break;
147 count = cp - path;
148 diffcount = count - oldcount + OFFSET;
149 oldcount = count;
150 if (diffcount < 0 || diffcount > 2 * OFFSET) {
151 if (putchar(SWITCH) == EOF ||
152 putw(diffcount, stdout) == EOF)
153 err(1, "stdout");
154 } else
155 if (putchar(diffcount) == EOF)
156 err(1, "stdout");
157
158 while (*cp != '\0') {
159 if (*(cp + 1) == '\0') {
160 if (putchar(*cp) == EOF)
161 err(1, "stdout");
162 break;
163 }
164 if ((code = bgindex(cp)) < 0) {
165 if (putchar(*cp++) == EOF ||
166 putchar(*cp++) == EOF)
167 err(1, "stdout");
168 } else {
169 /* Found, so mark byte with parity bit. */
170 if (putchar((code / 2) | PARITY) == EOF)
171 err(1, "stdout");
172 cp += 2;
173 }
174 }
175 if (path == buf1) { /* swap pointers */
176 path = buf2;
177 oldpath = buf1;
178 } else {
179 path = buf1;
180 oldpath = buf2;
181 }
182 }
183 /* Non-zero status if there were errors */
184 if (fflush(stdout) != 0 || ferror(stdout))
185 exit(1);
186 exit(0);
187 }
188
189 static int
bgindex(char * bg)190 bgindex(char *bg) /* Return location of bg in bigrams or -1. */
191 {
192 char bg0, bg1, *p;
193
194 bg0 = bg[0];
195 bg1 = bg[1];
196 for (p = bigrams; *p != '\0'; p += 2)
197 if (p[0] == bg0 && p[1] == bg1)
198 break;
199 return (*p == '\0' ? -1 : p - bigrams);
200 }
201
202 static void
usage(void)203 usage(void)
204 {
205 (void)fprintf(stderr,
206 "usage: locate.code common_bigrams < list > squozen_list\n");
207 exit(1);
208 }
209