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 37 #ifndef lint 38 static char copyright[] = 39 "@(#) Copyright (c) 1989, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 static char sccsid[] = "@(#)locate.code.c 8.4 (Berkeley) 5/4/95"; 45 #endif /* not lint */ 46 47 /* 48 * PURPOSE: sorted list compressor (works with a modified 'find' 49 * to encode/decode a filename database) 50 * 51 * USAGE: bigram < list > bigrams 52 * process bigrams (see updatedb) > common_bigrams 53 * code common_bigrams < list > squozen_list 54 * 55 * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1 56 * February/March 1983, p. 8). Output format is, per line, an 57 * offset differential count byte followed by a partially bigram- 58 * encoded ascii residue. A bigram is a two-character sequence, 59 * the first 128 most common of which are encoded in one byte. 60 * 61 * EXAMPLE: For simple front compression with no bigram encoding, 62 * if the input is... then the output is... 63 * 64 * /usr/src 0 /usr/src 65 * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c 66 * /usr/src/cmd/armadillo.c 14 armadillo.c 67 * /usr/tmp/zoo 5 tmp/zoo 68 * 69 * The codes are: 70 * 71 * 0-28 likeliest differential counts + offset to make nonnegative 72 * 30 switch code for out-of-range count to follow in next word 73 * 128-255 bigram codes (128 most common, as determined by 'updatedb') 74 * 32-127 single character (printable) ascii residue (ie, literal) 75 * 76 * SEE ALSO: updatedb.csh, bigram.c 77 * 78 * AUTHOR: James A. Woods, Informatics General Corp., 79 * NASA Ames Research Center, 10/82 80 */ 81 82 #include <sys/param.h> 83 84 #include <err.h> 85 #include <errno.h> 86 #include <stdio.h> 87 #include <stdlib.h> 88 #include <string.h> 89 #include <unistd.h> 90 91 #include "locate.h" 92 93 #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ 94 95 char buf1[MAXPATHLEN] = " "; 96 char buf2[MAXPATHLEN]; 97 char bigrams[BGBUFSIZE + 1] = { 0 }; 98 99 int bgindex __P((char *)); 100 void usage __P((void)); 101 102 int 103 main(argc, argv) 104 int argc; 105 char *argv[]; 106 { 107 register char *cp, *oldpath, *path; 108 int ch, code, count, diffcount, oldcount; 109 FILE *fp; 110 111 while ((ch = getopt(argc, argv, "")) != EOF) 112 switch(ch) { 113 case '?': 114 default: 115 usage(); 116 } 117 argc -= optind; 118 argv += optind; 119 120 if (argc != 1) 121 usage(); 122 123 if ((fp = fopen(argv[0], "r")) == NULL) 124 err(1, "%s", argv[0]); 125 126 /* First copy bigram array to stdout. */ 127 (void)fgets(bigrams, BGBUFSIZE + 1, fp); 128 if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) 129 err(1, "stdout"); 130 (void)fclose(fp); 131 132 oldpath = buf1; 133 path = buf2; 134 oldcount = 0; 135 while (fgets(path, sizeof(buf2), stdin) != NULL) { 136 /* Truncate newline. */ 137 cp = path + strlen(path) - 1; 138 if (cp > path && *cp == '\n') 139 *cp = '\0'; 140 141 /* Squelch characters that would botch the decoding. */ 142 for (cp = path; *cp != '\0'; cp++) { 143 if ((u_char)*cp >= PARITY || *cp <= SWITCH) 144 *cp = '?'; 145 } 146 147 /* Skip longest common prefix. */ 148 for (cp = path; *cp == *oldpath; cp++, oldpath++) 149 if (*oldpath == '\0') 150 break; 151 count = cp - path; 152 diffcount = count - oldcount + OFFSET; 153 oldcount = count; 154 if (diffcount < 0 || diffcount > 2 * OFFSET) { 155 if (putchar(SWITCH) == EOF || 156 putw(diffcount, stdout) == EOF) 157 err(1, "stdout"); 158 } else 159 if (putchar(diffcount) == EOF) 160 err(1, "stdout"); 161 162 while (*cp != '\0') { 163 if (*(cp + 1) == '\0') { 164 if (putchar(*cp) == EOF) 165 err(1, "stdout"); 166 break; 167 } 168 if ((code = bgindex(cp)) < 0) { 169 if (putchar(*cp++) == EOF || 170 putchar(*cp++) == EOF) 171 err(1, "stdout"); 172 } else { 173 /* Found, so mark byte with parity bit. */ 174 if (putchar((code / 2) | PARITY) == EOF) 175 err(1, "stdout"); 176 cp += 2; 177 } 178 } 179 if (path == buf1) { /* swap pointers */ 180 path = buf2; 181 oldpath = buf1; 182 } else { 183 path = buf1; 184 oldpath = buf2; 185 } 186 } 187 /* Non-zero status if there were errors */ 188 if (fflush(stdout) != 0 || ferror(stdout)) 189 exit(1); 190 exit(0); 191 } 192 193 int 194 bgindex(bg) /* Return location of bg in bigrams or -1. */ 195 char *bg; 196 { 197 register char bg0, bg1, *p; 198 199 bg0 = bg[0]; 200 bg1 = bg[1]; 201 for (p = bigrams; *p != '\0'; p++) 202 if (*p++ == bg0 && *p == bg1) 203 break; 204 return (*p == '\0' ? -1 : --p - bigrams); 205 } 206 207 void 208 usage() 209 { 210 (void)fprintf(stderr, 211 "usage: locate.code common_bigrams < list > squozen_list\n"); 212 exit(1); 213 } 214