xref: /dragonfly/usr.bin/locate/code/locate.code.c (revision 19fe1c42)
1 /*
2  * Copyright (c) 1995 Wolfram Schneider <wosch@FreeBSD.org>. Berlin.
3  * Copyright (c) 1989, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * James A. Woods.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * $FreeBSD: src/usr.bin/locate/code/locate.code.c,v 1.11.2.1 2001/03/04 08:46:46 kris Exp $
38  * $DragonFly: src/usr.bin/locate/code/locate.code.c,v 1.4 2005/08/04 17:31:23 drhodus Exp $
39  *
40  * @(#) Copyright (c) 1989, 1993 The Regents of the University of California.  All rights reserved.
41  * @(#)locate.code.c	8.1 (Berkeley) 6/6/93
42  */
43 
44 /*
45  * PURPOSE:	sorted list compressor (works with a modified 'find'
46  *		to encode/decode a filename database)
47  *
48  * USAGE:	bigram < list > bigrams
49  *		process bigrams (see updatedb) > common_bigrams
50  *		code common_bigrams < list > squozen_list
51  *
52  * METHOD:	Uses 'front compression' (see ";login:", Volume 8, Number 1
53  *		February/March 1983, p. 8).  Output format is, per line, an
54  *		offset differential count byte followed by a partially bigram-
55  *		encoded ascii residue.  A bigram is a two-character sequence,
56  *		the first 128 most common of which are encoded in one byte.
57  *
58  * EXAMPLE:	For simple front compression with no bigram encoding,
59  *		if the input is...		then the output is...
60  *
61  *		/usr/src			 0 /usr/src
62  *		/usr/src/cmd/aardvark.c		 8 /cmd/aardvark.c
63  *		/usr/src/cmd/armadillo.c	14 armadillo.c
64  *		/usr/tmp/zoo			 5 tmp/zoo
65  *
66  *	The codes are:
67  *
68  *	0-28	likeliest differential counts + offset to make nonnegative
69  *	30	switch code for out-of-range count to follow in next word
70  *      31      an 8 bit char followed
71  *	128-255 bigram codes (128 most common, as determined by 'updatedb')
72  *	32-127  single character (printable) ascii residue (ie, literal)
73  *
74  * The locate database store any character except newline ('\n')
75  * and NUL ('\0'). The 8-bit character support don't wast extra
76  * space until you have characters in file names less than 32
77  * or greather than 127.
78  *
79  *
80  * SEE ALSO:	updatedb.sh, ../bigram/locate.bigram.c
81  *
82  * AUTHOR:	James A. Woods, Informatics General Corp.,
83  *		NASA Ames Research Center, 10/82
84  *              8-bit file names characters:
85  *              	Wolfram Schneider, Berlin September 1996
86  */
87 
88 #include <sys/param.h>
89 #include <err.h>
90 #include <errno.h>
91 #include <stdlib.h>
92 #include <string.h>
93 #include <stdio.h>
94 #include <unistd.h>
95 #include "locate.h"
96 
97 #define	BGBUFSIZE	(NBG * 2)	/* size of bigram buffer */
98 
99 u_char buf1[MAXPATHLEN] = " ";
100 u_char buf2[MAXPATHLEN];
101 u_char bigrams[BGBUFSIZE + 1] = { 0 };
102 
103 #define LOOKUP 1 /* use a lookup array instead a function, 3x faster */
104 
105 #ifdef LOOKUP
106 #define BGINDEX(x) (big[(u_char)*x][(u_char)*(x + 1)])
107 typedef short bg_t;
108 bg_t big[UCHAR_MAX + 1][UCHAR_MAX + 1];
109 #else
110 #define BGINDEX(x) bgindex(x)
111 typedef int bg_t;
112 int	bgindex(char *);
113 #endif /* LOOKUP */
114 
115 
116 void	usage(void);
117 
118 int
119 main(argc, argv)
120 	int argc;
121 	char *argv[];
122 {
123 	u_char *cp, *oldpath, *path;
124 	int ch, code, count, diffcount, oldcount;
125 	FILE *fp;
126 	int i, j;
127 
128 	while ((ch = getopt(argc, argv, "")) != -1)
129 		switch(ch) {
130 		default:
131 			usage();
132 		}
133 	argc -= optind;
134 	argv += optind;
135 
136 	if (argc != 1)
137 		usage();
138 
139 	if ((fp = fopen(argv[0], "r")) == NULL)
140 		err(1, "%s", argv[0]);
141 
142 	/* First copy bigram array to stdout. */
143 	(void)fgets(bigrams, BGBUFSIZE + 1, fp);
144 
145 	if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE)
146 		err(1, "stdout");
147 	(void)fclose(fp);
148 
149 #ifdef LOOKUP
150 	/* init lookup table */
151 	for (i = 0; i < UCHAR_MAX + 1; i++)
152 	    	for (j = 0; j < UCHAR_MAX + 1; j++)
153 			big[i][j] = (bg_t)-1;
154 
155 	for (cp = bigrams, i = 0; *cp != '\0'; i += 2, cp += 2)
156 	        big[(u_char)*cp][(u_char)*(cp + 1)] = (bg_t)i;
157 
158 #endif /* LOOKUP */
159 
160 	oldpath = buf1;
161 	path = buf2;
162 	oldcount = 0;
163 
164 	while (fgets(path, sizeof(buf2), stdin) != NULL) {
165 
166 		/* skip empty lines */
167 		if (*path == '\n')
168 			continue;
169 
170 		/* remove newline */
171 		for (cp = path; *cp != '\0'; cp++) {
172 #ifndef LOCATE_CHAR30
173 			/* old locate implementations core'd for char 30 */
174 			if (*cp == SWITCH)
175 				*cp = '?';
176 			else
177 #endif /* !LOCATE_CHAR30 */
178 
179 			/* chop newline */
180 			if (*cp == '\n')
181 				*cp = '\0';
182 		}
183 
184 		/* Skip longest common prefix. */
185 		for (cp = path; *cp == *oldpath; cp++, oldpath++)
186 			if (*cp == '\0')
187 				break;
188 
189 		count = cp - path;
190 		diffcount = count - oldcount + OFFSET;
191 		oldcount = count;
192 		if (diffcount < 0 || diffcount > 2 * OFFSET) {
193 			if (putchar(SWITCH) == EOF ||
194 			    putw(diffcount, stdout) == EOF)
195 				err(1, "stdout");
196 		} else
197 			if (putchar(diffcount) == EOF)
198 				err(1, "stdout");
199 
200 		while (*cp != '\0') {
201 			/* print *two* characters */
202 
203 			if ((code = BGINDEX(cp)) != (bg_t)-1) {
204 				/*
205 				 * print *one* as bigram
206 				 * Found, so mark byte with
207 				 *  parity bit.
208 				 */
209 				if (putchar((code / 2) | PARITY) == EOF)
210 					err(1, "stdout");
211 				cp += 2;
212 			}
213 
214 			else {
215 				for (i = 0; i < 2; i++) {
216 					if (*cp == '\0')
217 						break;
218 
219 					/* print umlauts in file names */
220 					if (*cp < ASCII_MIN ||
221 					    *cp > ASCII_MAX) {
222 						if (putchar(UMLAUT) == EOF ||
223 						    putchar(*cp++) == EOF)
224 							err(1, "stdout");
225 					}
226 
227 					else {
228 						/* normal character */
229 						if(putchar(*cp++) == EOF)
230 							err(1, "stdout");
231 					}
232 				}
233 
234 			}
235 		}
236 
237 		if (path == buf1) {		/* swap pointers */
238 			path = buf2;
239 			oldpath = buf1;
240 		} else {
241 			path = buf1;
242 			oldpath = buf2;
243 		}
244 	}
245 	/* Non-zero status if there were errors */
246 	if (fflush(stdout) != 0 || ferror(stdout))
247 		exit(1);
248 	exit(0);
249 }
250 
251 #ifndef LOOKUP
252 int
253 bgindex(bg)			/* Return location of bg in bigrams or -1. */
254 	char *bg;
255 {
256 	char bg0, bg1, *p;
257 
258 	bg0 = bg[0];
259 	bg1 = bg[1];
260 	for (p = bigrams; *p != NULL; p++)
261 		if (*p++ == bg0 && *p == bg1)
262 			break;
263 	return (*p == NULL ? -1 : (--p - bigrams));
264 }
265 #endif /* !LOOKUP */
266 
267 void
268 usage()
269 {
270 	(void)fprintf(stderr,
271 	    "usage: locate.code common_bigrams < list > squozen_list\n");
272 	exit(1);
273 }
274