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 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 228 usage(void) 229 { 230 (void)fprintf(stderr, 231 "usage: locate.code common_bigrams < list > squozen_list\n"); 232 exit(1); 233 } 234