xref: /freebsd/usr.bin/locate/code/locate.code.c (revision 72a0982cd529c7cdeee7fd4eb7b1fd8bfdd545cb)
1 /*
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1995 Wolfram Schneider <wosch@FreeBSD.org>. Berlin.
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  * $FreeBSD$
36  */
37 
38 #if 0
39 #ifndef lint
40 static char copyright[] =
41 "@(#) Copyright (c) 1989, 1993\n\
42 	The Regents of the University of California.  All rights reserved.\n";
43 #endif /* not lint */
44 
45 #ifndef lint
46 static char sccsid[] = "@(#)locate.code.c	8.1 (Berkeley) 6/6/93";
47 #endif /* not lint */
48 #endif
49 
50 /*
51  * PURPOSE:	sorted list compressor (works with a modified 'find'
52  *		to encode/decode a filename database)
53  *
54  * USAGE:	bigram < list > bigrams
55  *		process bigrams (see updatedb) > common_bigrams
56  *		code common_bigrams < list > squozen_list
57  *
58  * METHOD:	Uses 'front compression' (see ";login:", Volume 8, Number 1
59  *		February/March 1983, p. 8).  Output format is, per line, an
60  *		offset differential count byte followed by a partially bigram-
61  *		encoded ascii residue.  A bigram is a two-character sequence,
62  *		the first 128 most common of which are encoded in one byte.
63  *
64  * EXAMPLE:	For simple front compression with no bigram encoding,
65  *		if the input is...		then the output is...
66  *
67  *		/usr/src			 0 /usr/src
68  *		/usr/src/cmd/aardvark.c		 8 /cmd/aardvark.c
69  *		/usr/src/cmd/armadillo.c	14 armadillo.c
70  *		/usr/tmp/zoo			 5 tmp/zoo
71  *
72  *	The codes are:
73  *
74  *	0-28	likeliest differential counts + offset to make nonnegative
75  *	30	switch code for out-of-range count to follow in next word
76  *      31      an 8 bit char followed
77  *	128-255 bigram codes (128 most common, as determined by 'updatedb')
78  *	32-127  single character (printable) ascii residue (ie, literal)
79  *
80  * The locate database store any character except newline ('\n')
81  * and NUL ('\0'). The 8-bit character support don't wast extra
82  * space until you have characters in file names less than 32
83  * or greather than 127.
84  *
85  *
86  * SEE ALSO:	updatedb.sh, ../bigram/locate.bigram.c
87  *
88  * AUTHOR:	James A. Woods, Informatics General Corp.,
89  *		NASA Ames Research Center, 10/82
90  *              8-bit file names characters:
91  *              	Wolfram Schneider, Berlin September 1996
92  */
93 
94 #include <sys/param.h>
95 #include <err.h>
96 #include <errno.h>
97 #include <stdlib.h>
98 #include <string.h>
99 #include <stdio.h>
100 #include <unistd.h>
101 #include "locate.h"
102 
103 #define	BGBUFSIZE	(NBG * 2)	/* size of bigram buffer */
104 
105 u_char buf1[MAXPATHLEN] = " ";
106 u_char buf2[MAXPATHLEN];
107 u_char bigrams[BGBUFSIZE + 1] = { 0 };
108 
109 #define LOOKUP 1 /* use a lookup array instead a function, 3x faster */
110 
111 #ifdef LOOKUP
112 #define BGINDEX(x) (big[(u_char)*x][(u_char)*(x + 1)])
113 typedef short bg_t;
114 bg_t big[UCHAR_MAX + 1][UCHAR_MAX + 1];
115 #else
116 #define BGINDEX(x) bgindex(x)
117 typedef int bg_t;
118 int	bgindex(char *);
119 #endif /* LOOKUP */
120 
121 
122 void	usage(void);
123 
124 int
125 main(int argc, char *argv[])
126 {
127 	u_char *cp, *oldpath, *path;
128 	int ch, code, count, diffcount, oldcount;
129 	u_int i, j;
130 	FILE *fp;
131 
132 	while ((ch = getopt(argc, argv, "")) != -1)
133 		switch(ch) {
134 		default:
135 			usage();
136 		}
137 	argc -= optind;
138 	argv += optind;
139 
140 	if (argc != 1)
141 		usage();
142 
143 	if ((fp = fopen(argv[0], "r")) == NULL)
144 		err(1, "%s", argv[0]);
145 
146 	/* First copy bigram array to stdout. */
147 	if (fgets(bigrams, BGBUFSIZE + 1, fp) == NULL)
148 		err(1, "get bigram array");
149 
150 	if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE)
151 		err(1, "stdout");
152 	(void)fclose(fp);
153 
154 #ifdef LOOKUP
155 	/* init lookup table */
156 	for (i = 0; i < UCHAR_MAX + 1; i++)
157 	    	for (j = 0; j < UCHAR_MAX + 1; j++)
158 			big[i][j] = (bg_t)-1;
159 
160 	for (cp = bigrams, i = 0; *cp != '\0'; i += 2, cp += 2)
161 	        big[(u_char)*cp][(u_char)*(cp + 1)] = (bg_t)i;
162 
163 #endif /* LOOKUP */
164 
165 	oldpath = buf1;
166 	path = buf2;
167 	oldcount = 0;
168 
169 	while (fgets(path, sizeof(buf2), stdin) != NULL) {
170 
171 		/* skip empty lines */
172 		if (*path == '\n')
173 			continue;
174 
175 		/* remove newline */
176 		for (cp = path; *cp != '\0'; cp++) {
177 #ifndef LOCATE_CHAR30
178 			/* old locate implementations core'd for char 30 */
179 			if (*cp == SWITCH)
180 				*cp = '?';
181 			else
182 #endif /* !LOCATE_CHAR30 */
183 
184 			/* chop newline */
185 			if (*cp == '\n')
186 				*cp = '\0';
187 		}
188 
189 		/* Skip longest common prefix. */
190 		for (cp = path; *cp == *oldpath; cp++, oldpath++)
191 			if (*cp == '\0')
192 				break;
193 
194 		count = cp - path;
195 		diffcount = count - oldcount + OFFSET;
196 		oldcount = count;
197 		if (diffcount < 0 || diffcount > 2 * OFFSET) {
198 			if (putchar(SWITCH) == EOF ||
199 			    putw(diffcount, stdout) == EOF)
200 				err(1, "stdout");
201 		} else
202 			if (putchar(diffcount) == EOF)
203 				err(1, "stdout");
204 
205 		while (*cp != '\0') {
206 			/* print *two* characters */
207 
208 			if ((code = BGINDEX(cp)) != (bg_t)-1) {
209 				/*
210 				 * print *one* as bigram
211 				 * Found, so mark byte with
212 				 *  parity bit.
213 				 */
214 				if (putchar((code / 2) | PARITY) == EOF)
215 					err(1, "stdout");
216 				cp += 2;
217 			}
218 
219 			else {
220 				for (i = 0; i < 2; i++) {
221 					if (*cp == '\0')
222 						break;
223 
224 					/* print umlauts in file names */
225 					if (*cp < ASCII_MIN ||
226 					    *cp > ASCII_MAX) {
227 						if (putchar(UMLAUT) == EOF ||
228 						    putchar(*cp++) == EOF)
229 							err(1, "stdout");
230 					}
231 
232 					else {
233 						/* normal character */
234 						if(putchar(*cp++) == EOF)
235 							err(1, "stdout");
236 					}
237 				}
238 
239 			}
240 		}
241 
242 		if (path == buf1) {		/* swap pointers */
243 			path = buf2;
244 			oldpath = buf1;
245 		} else {
246 			path = buf1;
247 			oldpath = buf2;
248 		}
249 	}
250 
251 	/* Non-zero status if there were errors */
252 	if (fflush(stdout) != 0 || ferror(stdout))
253 		errx(1, "stdout");
254 
255 	exit(0);
256 }
257 
258 #ifndef LOOKUP
259 int
260 bgindex(char *bg)		/* Return location of bg in bigrams or -1. */
261 {
262 	char bg0, bg1, *p;
263 
264 	bg0 = bg[0];
265 	bg1 = bg[1];
266 	for (p = bigrams; *p != NULL; p++)
267 		if (*p++ == bg0 && *p == bg1)
268 			break;
269 	return (*p == NULL ? -1 : (--p - bigrams));
270 }
271 #endif /* !LOOKUP */
272 
273 void
274 usage(void)
275 {
276 	(void)fprintf(stderr,
277 	    "usage: locate.code common_bigrams < list > squozen_list\n");
278 	exit(1);
279 }
280