1 /* $NetBSD: locate.code.c,v 1.3 1994/12/22 06:17:43 jtc 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 #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 #if 0 47 static char sccsid[] = "@(#)locate.code.c 8.1 (Berkeley) 6/6/93"; 48 #endif 49 static char rcsid[] = "$NetBSD: locate.code.c,v 1.3 1994/12/22 06:17:43 jtc 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 #include <err.h> 89 #include <errno.h> 90 #include <stdlib.h> 91 #include <string.h> 92 #include <stdio.h> 93 #include "locate.h" 94 95 #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ 96 97 char buf1[MAXPATHLEN] = " "; 98 char buf2[MAXPATHLEN]; 99 char bigrams[BGBUFSIZE + 1] = { 0 }; 100 101 int bgindex __P((char *)); 102 void usage __P((void)); 103 104 int 105 main(argc, argv) 106 int argc; 107 char *argv[]; 108 { 109 register char *cp, *oldpath, *path; 110 int ch, code, count, diffcount, oldcount; 111 FILE *fp; 112 113 while ((ch = getopt(argc, argv, "")) != EOF) 114 switch(ch) { 115 case '?': 116 default: 117 usage(); 118 } 119 argc -= optind; 120 argv += optind; 121 122 if (argc != 1) 123 usage(); 124 125 if ((fp = fopen(argv[0], "r")) == NULL) 126 err(1, "%s", argv[0]); 127 128 /* First copy bigram array to stdout. */ 129 (void)fgets(bigrams, BGBUFSIZE + 1, fp); 130 if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) 131 err(1, "stdout"); 132 (void)fclose(fp); 133 134 oldpath = buf1; 135 path = buf2; 136 oldcount = 0; 137 while (fgets(path, sizeof(buf2), stdin) != NULL) { 138 /* Truncate newline. */ 139 cp = path + strlen(path) - 1; 140 if (cp > path && *cp == '\n') 141 *cp = '\0'; 142 143 /* Squelch characters that would botch the decoding. */ 144 for (cp = path; *cp != NULL; cp++) { 145 if ((u_char)*cp >= PARITY) 146 *cp &= PARITY-1; 147 else if (*cp <= SWITCH) 148 *cp = '?'; 149 } 150 151 /* Skip longest common prefix. */ 152 for (cp = path; *cp == *oldpath; cp++, oldpath++) 153 if (*oldpath == NULL) 154 break; 155 count = cp - path; 156 diffcount = count - oldcount + OFFSET; 157 oldcount = count; 158 if (diffcount < 0 || diffcount > 2 * OFFSET) { 159 if (putchar(SWITCH) == EOF || 160 putw(diffcount, stdout) == EOF) 161 err(1, "stdout"); 162 } else 163 if (putchar(diffcount) == EOF) 164 err(1, "stdout"); 165 166 while (*cp != NULL) { 167 if (*(cp + 1) == NULL) { 168 if (putchar(*cp) == EOF) 169 err(1, "stdout"); 170 break; 171 } 172 if ((code = bgindex(cp)) < 0) { 173 if (putchar(*cp++) == EOF || 174 putchar(*cp++) == EOF) 175 err(1, "stdout"); 176 } else { 177 /* Found, so mark byte with parity bit. */ 178 if (putchar((code / 2) | PARITY) == EOF) 179 err(1, "stdout"); 180 cp += 2; 181 } 182 } 183 if (path == buf1) { /* swap pointers */ 184 path = buf2; 185 oldpath = buf1; 186 } else { 187 path = buf1; 188 oldpath = buf2; 189 } 190 } 191 /* Non-zero status if there were errors */ 192 if (fflush(stdout) != 0 || ferror(stdout)) 193 exit(1); 194 exit(0); 195 } 196 197 int 198 bgindex(bg) /* Return location of bg in bigrams or -1. */ 199 char *bg; 200 { 201 register char bg0, bg1, *p; 202 203 bg0 = bg[0]; 204 bg1 = bg[1]; 205 for (p = bigrams; *p != NULL; p++) 206 if (*p++ == bg0 && *p == bg1) 207 break; 208 return (*p == NULL ? -1 : --p - bigrams); 209 } 210 211 void 212 usage() 213 { 214 (void)fprintf(stderr, 215 "usage: locate.code common_bigrams < list > squozen_list\n"); 216 exit(1); 217 } 218