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