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/* $NetBSD: locate.code.c,v 1.5 1995/08/31 22:36:33 jtc 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.
*/
#ifndef lint
static char 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
static char rcsid[] = "$NetBSD: locate.code.c,v 1.5 1995/08/31 22:36:33 jtc 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 *));
void usage __P((void));
int
main(argc, argv)
int argc;
char *argv[];
{
register char *cp, *oldpath, *path;
int ch, code, count, diffcount, oldcount;
FILE *fp;
while ((ch = getopt(argc, argv, "")) != EOF)
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;
{
register 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);
}
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