/* * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1995-2022 Wolfram Schneider <wosch@FreeBSD.org> * 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. 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. */ /* * 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 * 31 an 8 bit char followed * 128-255 bigram codes (128 most common, as determined by 'updatedb') * 32-127 single character (printable) ascii residue (ie, literal) * * The locate database store any character except newline ('\n') * and NUL ('\0'). The 8-bit character support don't wast extra * space until you have characters in file names less than 32 * or greather than 127. * * * SEE ALSO: updatedb.sh, ../bigram/locate.bigram.c * * AUTHOR: James A. Woods, Informatics General Corp., * NASA Ames Research Center, 10/82 * 8-bit file names characters: * Wolfram Schneider, Berlin September 1996 */ #include <sys/param.h> #include <err.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <stdio.h> #include <unistd.h> #include "locate.h" #define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ u_char buf1[LOCATE_PATH_MAX] = " "; u_char buf2[LOCATE_PATH_MAX]; u_char bigrams[BGBUFSIZE + 1] = { 0 }; /* use a lookup array instead a function, 3x faster than linear search */ int big [UCHAR_MAX + 1][UCHAR_MAX + 1]; #define BGINDEX(x) (big[(u_char)*x][(u_char)*(x + 1)]) void usage(void); int main(int argc, char *argv[]) { u_char *cp, *oldpath, *path; int ch, code, count, diffcount, oldcount; u_int i, j; FILE *fp; while ((ch = getopt(argc, argv, "")) != -1) switch(ch) { 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. */ if (fgets(bigrams, BGBUFSIZE + 1, fp) == NULL) { if (!feof(fp) || ferror(fp)) err(1, "get bigram array"); } if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) err(1, "stdout"); (void)fclose(fp); /* init lookup table */ for (i = 0; i < UCHAR_MAX + 1; i++) for (j = 0; j < UCHAR_MAX + 1; j++) big[i][j] = -1; for (cp = bigrams, i = 0; *cp != '\0'; i += 2, cp += 2) big[(u_char)*cp][(u_char)*(cp + 1)] = i; oldpath = buf1; path = buf2; oldcount = 0; while (fgets(path, sizeof(buf2), stdin) != NULL) { /* skip empty lines */ if (*path == '\n') continue; /* remove newline */ for (cp = path; *cp != '\0'; cp++) { /* chop newline */ if (*cp == '\n') *cp = '\0'; } /* Skip longest common prefix. */ for (cp = path; *cp == *oldpath; cp++, oldpath++) if (*cp == '\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') { /* print *two* characters */ if ((code = BGINDEX(cp)) != -1) { /* * print *one* as bigram * Found, so mark byte with * parity bit. */ if (putchar((code / 2) | PARITY) == EOF) err(1, "stdout"); cp += 2; } else { for (i = 0; i < 2; i++) { if (*cp == '\0') break; /* print umlauts in file names */ if (*cp < ASCII_MIN || *cp > ASCII_MAX) { if (putchar(UMLAUT) == EOF || putchar(*cp++) == EOF) err(1, "stdout"); } else { /* normal character */ if(putchar(*cp++) == EOF) err(1, "stdout"); } } } } 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)) errx(1, "stdout"); exit(0); } void usage(void) { (void)fprintf(stderr, "usage: locate.code common_bigrams < list > squozen_list\n"); exit(1); }
