usr.bin/locate/code/locate.code.c

   1 /*      $NetBSD: locate.code.c,v 1.9 2003/08/07 11:14:20 agc 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 1.9 2003/08/07 11:14:20 agc 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 char buf1[MAXPATHLEN] = " ";
  97 char buf2[MAXPATHLEN];
  98 char bigrams[BGBUFSIZE + 1] = { 0 };
  99
 100 int     bgindex __P((char *));
 101 int     main __P((int, char **));
 102 void    usage __P((void));
 103
 104 int
 105 main(argc, argv)
 106         int argc;
 107         char *argv[];
 108 {
 109         char *cp, *oldpath, *path;
 110         int ch, code, count, diffcount, oldcount;
 111
 112         while ((ch = getopt(argc, argv, "")) != -1)
 113                 switch(ch) {
 114                 case '?':
 115                 default:
 116                         usage();
 117                 }
 118         argc -= optind;
 119         argv += optind;
 120
 121         if (argc != 1)
 122                 usage();
 123
 124         /* First copy bigram array to stdout. */
 125         strncpy(bigrams, argv[0], BGBUFSIZE + 1);
 126         if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE)
 127                 err(1, "stdout");
 128
 129         oldpath = buf1;
 130         path = buf2;
 131         oldcount = 0;
 132         while (fgets(path, sizeof(buf2), stdin) != NULL) {
 133                 /* Truncate newline. */
 134                 cp = path + strlen(path) - 1;
 135                 if (cp > path && *cp == '\n')
 136                         *cp = '\0';
 137
 138                 /* Squelch characters that would botch the decoding. */
 139                 for (cp = path; *cp != '\0'; cp++) {
 140                         *cp &= PARITY-1;
 141                         if (*cp <= SWITCH)
 142                                 *cp = '?';
 143                 }
 144
 145                 /* Skip longest common prefix. */
 146                 for (cp = path; *cp == *oldpath; cp++, oldpath++)
 147                         if (*oldpath == '\0')
 148                                 break;
 149                 count = cp - path;
 150                 diffcount = count - oldcount + OFFSET;
 151                 oldcount = count;
 152                 if (diffcount < 0 || diffcount > 2 * OFFSET) {
 153                         if (putchar(SWITCH) == EOF ||
 154                             putw(diffcount, stdout) == EOF)
 155                                 err(1, "stdout");
 156                 } else
 157                         if (putchar(diffcount) == EOF)
 158                                 err(1, "stdout");
 159
 160                 while (*cp != '\0') {
 161                         if (*(cp + 1) == '\0') {
 162                                 if (putchar(*cp) == EOF)
 163                                         err(1, "stdout");
 164                                 break;
 165                         }
 166                         if ((code = bgindex(cp)) < 0) {
 167                                 if (putchar(*cp++) == EOF ||
 168                                     putchar(*cp++) == EOF)
 169                                         err(1, "stdout");
 170                         } else {
 171                                 /* Found, so mark byte with parity bit. */
 172                                 if (putchar((code / 2) | PARITY) == EOF)
 173                                         err(1, "stdout");
 174                                 cp += 2;
 175                         }
 176                 }
 177                 if (path == buf1) {             /* swap pointers */
 178                         path = buf2;
 179                         oldpath = buf1;
 180                 } else {
 181                         path = buf1;
 182                         oldpath = buf2;
 183                 }
 184         }
 185         /* Non-zero status if there were errors */
 186         if (fflush(stdout) != 0 || ferror(stdout))
 187                 exit(1);
 188         exit(0);
 189 }
 190
 191 int
 192 bgindex(bg)                     /* Return location of bg in bigrams or -1. */
 193         char *bg;
 194 {
 195         char bg0, bg1, *p;
 196
 197         bg0 = bg[0];
 198         bg1 = bg[1];
 199         for (p = bigrams; *p != '\0'; p += 2)
 200                 if (p[0] == bg0 && p[1] == bg1)
 201                         break;
 202         return (*p == '\0' ? -1 : p - bigrams);
 203 }
 204
 205 void
 206 usage()
 207 {
 208         (void)fprintf(stderr,
 209             "usage: locate.code common_bigrams < list > squozen_list\n");
 210         exit(1);
 211 }