1 /*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1995-2022 Wolfram Schneider <wosch@FreeBSD.org>
5 * Copyright (c) 1989, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * James A. Woods.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * PURPOSE: sorted list compressor (works with a modified 'find'
38 * to encode/decode a filename database)
39 *
40 * USAGE: bigram < list > bigrams
41 * process bigrams (see updatedb) > common_bigrams
42 * code common_bigrams < list > squozen_list
43 *
44 * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1
45 * February/March 1983, p. 8). Output format is, per line, an
46 * offset differential count byte followed by a partially bigram-
47 * encoded ascii residue. A bigram is a two-character sequence,
48 * the first 128 most common of which are encoded in one byte.
49 *
50 * EXAMPLE: For simple front compression with no bigram encoding,
51 * if the input is... then the output is...
52 *
53 * /usr/src 0 /usr/src
54 * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c
55 * /usr/src/cmd/armadillo.c 14 armadillo.c
56 * /usr/tmp/zoo 5 tmp/zoo
57 *
58 * The codes are:
59 *
60 * 0-28 likeliest differential counts + offset to make nonnegative
61 * 30 switch code for out-of-range count to follow in next word
62 * 31 an 8 bit char followed
63 * 128-255 bigram codes (128 most common, as determined by 'updatedb')
64 * 32-127 single character (printable) ascii residue (ie, literal)
65 *
66 * The locate database store any character except newline ('\n')
67 * and NUL ('\0'). The 8-bit character support don't wast extra
68 * space until you have characters in file names less than 32
69 * or greather than 127.
70 *
71 *
72 * SEE ALSO: updatedb.sh, ../bigram/locate.bigram.c
73 *
74 * AUTHOR: James A. Woods, Informatics General Corp.,
75 * NASA Ames Research Center, 10/82
76 * 8-bit file names characters:
77 * Wolfram Schneider, Berlin September 1996
78 */
79
80 #include <sys/param.h>
81 #include <err.h>
82 #include <errno.h>
83 #include <stdlib.h>
84 #include <string.h>
85 #include <stdio.h>
86 #include <unistd.h>
87 #include "locate.h"
88
89 #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */
90
91 u_char buf1[LOCATE_PATH_MAX] = " ";
92 u_char buf2[LOCATE_PATH_MAX];
93 u_char bigrams[BGBUFSIZE + 1] = { 0 };
94
95 /* use a lookup array instead a function, 3x faster than linear search */
96 int big [UCHAR_MAX + 1][UCHAR_MAX + 1];
97 #define BGINDEX(x) (big[(u_char)*x][(u_char)*(x + 1)])
98
99 void usage(void);
100
101 int
main(int argc,char * argv[])102 main(int argc, char *argv[])
103 {
104 u_char *cp, *oldpath, *path;
105 int ch, code, count, diffcount, oldcount;
106 u_int i, j;
107 FILE *fp;
108
109 while ((ch = getopt(argc, argv, "")) != -1)
110 switch(ch) {
111 default:
112 usage();
113 }
114 argc -= optind;
115 argv += optind;
116
117 if (argc != 1)
118 usage();
119
120 if ((fp = fopen(argv[0], "r")) == NULL)
121 err(1, "%s", argv[0]);
122
123 /* First copy bigram array to stdout. */
124 if (fgets(bigrams, BGBUFSIZE + 1, fp) == NULL) {
125 if (!feof(fp) || ferror(fp))
126 err(1, "get bigram array");
127 }
128
129 if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE)
130 err(1, "stdout");
131 (void)fclose(fp);
132
133 /* init lookup table */
134 for (i = 0; i < UCHAR_MAX + 1; i++)
135 for (j = 0; j < UCHAR_MAX + 1; j++)
136 big[i][j] = -1;
137
138 for (cp = bigrams, i = 0; *cp != '\0'; i += 2, cp += 2)
139 big[(u_char)*cp][(u_char)*(cp + 1)] = i;
140
141 oldpath = buf1;
142 path = buf2;
143 oldcount = 0;
144
145 while (fgets(path, sizeof(buf2), stdin) != NULL) {
146
147 /* skip empty lines */
148 if (*path == '\n')
149 continue;
150
151 /* remove newline */
152 for (cp = path; *cp != '\0'; cp++) {
153 /* chop newline */
154 if (*cp == '\n')
155 *cp = '\0';
156 }
157
158 /* Skip longest common prefix. */
159 for (cp = path; *cp == *oldpath; cp++, oldpath++)
160 if (*cp == '\0')
161 break;
162
163 count = cp - path;
164 diffcount = count - oldcount + OFFSET;
165 oldcount = count;
166 if (diffcount < 0 || diffcount > 2 * OFFSET) {
167 if (putchar(SWITCH) == EOF ||
168 putw(diffcount, stdout) == EOF)
169 err(1, "stdout");
170 } else
171 if (putchar(diffcount) == EOF)
172 err(1, "stdout");
173
174 while (*cp != '\0') {
175 /* print *two* characters */
176
177 if ((code = BGINDEX(cp)) != -1) {
178 /*
179 * print *one* as bigram
180 * Found, so mark byte with
181 * parity bit.
182 */
183 if (putchar((code / 2) | PARITY) == EOF)
184 err(1, "stdout");
185 cp += 2;
186 }
187
188 else {
189 for (i = 0; i < 2; i++) {
190 if (*cp == '\0')
191 break;
192
193 /* print umlauts in file names */
194 if (*cp < ASCII_MIN ||
195 *cp > ASCII_MAX) {
196 if (putchar(UMLAUT) == EOF ||
197 putchar(*cp++) == EOF)
198 err(1, "stdout");
199 }
200
201 else {
202 /* normal character */
203 if(putchar(*cp++) == EOF)
204 err(1, "stdout");
205 }
206 }
207
208 }
209 }
210
211 if (path == buf1) { /* swap pointers */
212 path = buf2;
213 oldpath = buf1;
214 } else {
215 path = buf1;
216 oldpath = buf2;
217 }
218 }
219
220 /* Non-zero status if there were errors */
221 if (fflush(stdout) != 0 || ferror(stdout))
222 errx(1, "stdout");
223
224 exit(0);
225 }
226
227 void
usage(void)228 usage(void)
229 {
230 (void)fprintf(stderr,
231 "usage: locate.code common_bigrams < list > squozen_list\n");
232 exit(1);
233 }
234