/* $NetBSD: locate.code.c,v 1.6 1997/10/19 04:11:54 lukem Exp $ */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * James A. Woods. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/cdefs.h> #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\ The Regents of the University of California. All rights reserved.\n"); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)locate.code.c 8.4 (Berkeley) 5/4/95"; #endif __RCSID("$NetBSD: locate.code.c,v 1.6 1997/10/19 04:11:54 lukem Exp $"); #endif /* not lint */ /* * PURPOSE: sorted list compressor (works with a modified 'find' * to encode/decode a filename database) * * USAGE: bigram < list > bigrams * process bigrams (see updatedb) > common_bigrams * code common_bigrams < list > squozen_list * * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1 * February/March 1983, p. 8). Output format is, per line, an * offset differential count byte followed by a partially bigram- * encoded ascii residue. A bigram is a two-character sequence, * the first 128 most common of which are encoded in one byte. * * EXAMPLE: For simple front compression with no bigram encoding, * if the input is... then the output is... * * /usr/src 0 /usr/src * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c * /usr/src/cmd/armadillo.c 14 armadillo.c * /usr/tmp/zoo 5 tmp/zoo * * The codes are: * * 0-28 likeliest differential counts + offset to make nonnegative * 30 switch code for out-of-range count to follow in next word * 128-255 bigram codes (128 most common, as determined by 'updatedb') * 32-127 single character (printable) ascii residue (ie, literal) * * SEE ALSO: updatedb.csh, bigram.c * * AUTHOR: James A. Woods, Informatics General Corp., * NASA Ames Research Center, 10/82 */ #include <sys/param.h> #include <err.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "locate.h" #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ char buf1[MAXPATHLEN] = " "; char buf2[MAXPATHLEN]; char bigrams[BGBUFSIZE + 1] = { 0 }; int bgindex __P((char *)); int main __P((int, char **)); void usage __P((void)); int main(argc, argv) int argc; char *argv[]; { char *cp, *oldpath, *path; int ch, code, count, diffcount, oldcount; FILE *fp; while ((ch = getopt(argc, argv, "")) != -1) switch(ch) { case '?': default: usage(); } argc -= optind; argv += optind; if (argc != 1) usage(); if ((fp = fopen(argv[0], "r")) == NULL) err(1, "%s", argv[0]); /* First copy bigram array to stdout. */ (void)fgets(bigrams, BGBUFSIZE + 1, fp); if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) err(1, "stdout"); (void)fclose(fp); oldpath = buf1; path = buf2; oldcount = 0; while (fgets(path, sizeof(buf2), stdin) != NULL) { /* Truncate newline. */ cp = path + strlen(path) - 1; if (cp > path && *cp == '\n') *cp = '\0'; /* Squelch characters that would botch the decoding. */ for (cp = path; *cp != '\0'; cp++) { *cp &= PARITY-1; if (*cp <= SWITCH) *cp = '?'; } /* Skip longest common prefix. */ for (cp = path; *cp == *oldpath; cp++, oldpath++) if (*oldpath == '\0') break; count = cp - path; diffcount = count - oldcount + OFFSET; oldcount = count; if (diffcount < 0 || diffcount > 2 * OFFSET) { if (putchar(SWITCH) == EOF || putw(diffcount, stdout) == EOF) err(1, "stdout"); } else if (putchar(diffcount) == EOF) err(1, "stdout"); while (*cp != '\0') { if (*(cp + 1) == '\0') { if (putchar(*cp) == EOF) err(1, "stdout"); break; } if ((code = bgindex(cp)) < 0) { if (putchar(*cp++) == EOF || putchar(*cp++) == EOF) err(1, "stdout"); } else { /* Found, so mark byte with parity bit. */ if (putchar((code / 2) | PARITY) == EOF) err(1, "stdout"); cp += 2; } } if (path == buf1) { /* swap pointers */ path = buf2; oldpath = buf1; } else { path = buf1; oldpath = buf2; } } /* Non-zero status if there were errors */ if (fflush(stdout) != 0 || ferror(stdout)) exit(1); exit(0); } int bgindex(bg) /* Return location of bg in bigrams or -1. */ char *bg; { char bg0, bg1, *p; bg0 = bg[0]; bg1 = bg[1]; for (p = bigrams; *p != '\0'; p++) if (*p++ == bg0 && *p == bg1) break; return (*p == '\0' ? -1 : --p - bigrams); } void usage() { (void)fprintf(stderr, "usage: locate.code common_bigrams < list > squozen_list\n"); exit(1); }