1 /* $NetBSD: locate.code.c,v 1.8 2000/05/06 10:02:06 mycroft 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) 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 #if 0 47 static char sccsid[] = "@(#)locate.code.c 8.4 (Berkeley) 5/4/95"; 48 #endif 49 __RCSID("$NetBSD: locate.code.c,v 1.8 2000/05/06 10:02:06 mycroft Exp $"); 50 #endif /* not lint */ 51 52 /* 53 * PURPOSE: sorted list compressor (works with a modified 'find' 54 * to encode/decode a filename database) 55 * 56 * USAGE: bigram < list > bigrams 57 * process bigrams (see updatedb) > common_bigrams 58 * code common_bigrams < list > squozen_list 59 * 60 * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1 61 * February/March 1983, p. 8). Output format is, per line, an 62 * offset differential count byte followed by a partially bigram- 63 * encoded ascii residue. A bigram is a two-character sequence, 64 * the first 128 most common of which are encoded in one byte. 65 * 66 * EXAMPLE: For simple front compression with no bigram encoding, 67 * if the input is... then the output is... 68 * 69 * /usr/src 0 /usr/src 70 * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c 71 * /usr/src/cmd/armadillo.c 14 armadillo.c 72 * /usr/tmp/zoo 5 tmp/zoo 73 * 74 * The codes are: 75 * 76 * 0-28 likeliest differential counts + offset to make nonnegative 77 * 30 switch code for out-of-range count to follow in next word 78 * 128-255 bigram codes (128 most common, as determined by 'updatedb') 79 * 32-127 single character (printable) ascii residue (ie, literal) 80 * 81 * SEE ALSO: updatedb.csh, bigram.c 82 * 83 * AUTHOR: James A. Woods, Informatics General Corp., 84 * NASA Ames Research Center, 10/82 85 */ 86 87 #include <sys/param.h> 88 89 #include <err.h> 90 #include <errno.h> 91 #include <stdio.h> 92 #include <stdlib.h> 93 #include <string.h> 94 #include <unistd.h> 95 96 #include "locate.h" 97 98 #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ 99 100 char buf1[MAXPATHLEN] = " "; 101 char buf2[MAXPATHLEN]; 102 char bigrams[BGBUFSIZE + 1] = { 0 }; 103 104 int bgindex __P((char *)); 105 int main __P((int, char **)); 106 void usage __P((void)); 107 108 int 109 main(argc, argv) 110 int argc; 111 char *argv[]; 112 { 113 char *cp, *oldpath, *path; 114 int ch, code, count, diffcount, oldcount; 115 116 while ((ch = getopt(argc, argv, "")) != -1) 117 switch(ch) { 118 case '?': 119 default: 120 usage(); 121 } 122 argc -= optind; 123 argv += optind; 124 125 if (argc != 1) 126 usage(); 127 128 /* First copy bigram array to stdout. */ 129 strncpy(bigrams, argv[0], BGBUFSIZE + 1); 130 if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) 131 err(1, "stdout"); 132 133 oldpath = buf1; 134 path = buf2; 135 oldcount = 0; 136 while (fgets(path, sizeof(buf2), stdin) != NULL) { 137 /* Truncate newline. */ 138 cp = path + strlen(path) - 1; 139 if (cp > path && *cp == '\n') 140 *cp = '\0'; 141 142 /* Squelch characters that would botch the decoding. */ 143 for (cp = path; *cp != '\0'; cp++) { 144 *cp &= PARITY-1; 145 if (*cp <= SWITCH) 146 *cp = '?'; 147 } 148 149 /* Skip longest common prefix. */ 150 for (cp = path; *cp == *oldpath; cp++, oldpath++) 151 if (*oldpath == '\0') 152 break; 153 count = cp - path; 154 diffcount = count - oldcount + OFFSET; 155 oldcount = count; 156 if (diffcount < 0 || diffcount > 2 * OFFSET) { 157 if (putchar(SWITCH) == EOF || 158 putw(diffcount, stdout) == EOF) 159 err(1, "stdout"); 160 } else 161 if (putchar(diffcount) == EOF) 162 err(1, "stdout"); 163 164 while (*cp != '\0') { 165 if (*(cp + 1) == '\0') { 166 if (putchar(*cp) == EOF) 167 err(1, "stdout"); 168 break; 169 } 170 if ((code = bgindex(cp)) < 0) { 171 if (putchar(*cp++) == EOF || 172 putchar(*cp++) == EOF) 173 err(1, "stdout"); 174 } else { 175 /* Found, so mark byte with parity bit. */ 176 if (putchar((code / 2) | PARITY) == EOF) 177 err(1, "stdout"); 178 cp += 2; 179 } 180 } 181 if (path == buf1) { /* swap pointers */ 182 path = buf2; 183 oldpath = buf1; 184 } else { 185 path = buf1; 186 oldpath = buf2; 187 } 188 } 189 /* Non-zero status if there were errors */ 190 if (fflush(stdout) != 0 || ferror(stdout)) 191 exit(1); 192 exit(0); 193 } 194 195 int 196 bgindex(bg) /* Return location of bg in bigrams or -1. */ 197 char *bg; 198 { 199 char bg0, bg1, *p; 200 201 bg0 = bg[0]; 202 bg1 = bg[1]; 203 for (p = bigrams; *p != '\0'; p += 2) 204 if (p[0] == bg0 && p[1] == bg1) 205 break; 206 return (*p == '\0' ? -1 : p - bigrams); 207 } 208 209 void 210 usage() 211 { 212 (void)fprintf(stderr, 213 "usage: locate.code common_bigrams < list > squozen_list\n"); 214 exit(1); 215 } 216