1994-09-04 04:03:31 +00:00
|
|
|
/*
|
|
|
|
* Copyright (c) 1989, 1993
|
|
|
|
* The Regents of the University of California. All rights reserved.
|
|
|
|
*
|
|
|
|
* This code is derived from software contributed to Berkeley by
|
|
|
|
* Rick Adams.
|
|
|
|
*
|
|
|
|
* Authors:
|
|
|
|
* Stan King, John Eldridge, based on algorithm suggested by
|
|
|
|
* Bob Morris
|
|
|
|
* 29-Sep-82
|
|
|
|
*
|
|
|
|
* 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.
|
1999-11-16 02:45:03 +00:00
|
|
|
*
|
|
|
|
* $FreeBSD$
|
1994-09-04 04:03:31 +00:00
|
|
|
*/
|
|
|
|
|
|
|
|
#ifndef lint
|
1996-05-27 08:50:53 +00:00
|
|
|
static const char copyright[] =
|
1994-09-04 04:03:31 +00:00
|
|
|
"@(#) Copyright (c) 1989, 1993\n\
|
|
|
|
The Regents of the University of California. All rights reserved.\n";
|
|
|
|
#endif /* not lint */
|
|
|
|
|
|
|
|
#ifndef lint
|
1999-09-15 01:58:44 +00:00
|
|
|
#if 0
|
1996-05-27 08:50:53 +00:00
|
|
|
static const char sccsid[] = "@(#)caesar.c 8.1 (Berkeley) 5/31/93";
|
1999-09-15 01:58:44 +00:00
|
|
|
#else
|
|
|
|
static const char rcsid[] =
|
|
|
|
"$FreeBSD$";
|
|
|
|
#endif
|
1994-09-04 04:03:31 +00:00
|
|
|
#endif /* not lint */
|
|
|
|
|
1996-05-27 08:50:53 +00:00
|
|
|
#include <errno.h>
|
1994-09-04 04:03:31 +00:00
|
|
|
#include <math.h>
|
|
|
|
#include <stdio.h>
|
1996-05-27 08:50:53 +00:00
|
|
|
#include <stdlib.h>
|
|
|
|
#include <string.h>
|
1994-09-04 04:03:31 +00:00
|
|
|
#include <ctype.h>
|
|
|
|
#include <unistd.h>
|
|
|
|
|
|
|
|
#define LINELENGTH 2048
|
|
|
|
#define ROTATE(ch, perm) \
|
1996-05-27 08:50:53 +00:00
|
|
|
isascii(ch) ? ( \
|
1994-09-04 04:03:31 +00:00
|
|
|
isupper(ch) ? ('A' + (ch - 'A' + perm) % 26) : \
|
1996-05-27 08:50:53 +00:00
|
|
|
islower(ch) ? ('a' + (ch - 'a' + perm) % 26) : ch) : ch
|
1994-09-04 04:03:31 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* letter frequencies (taken from some unix(tm) documentation)
|
|
|
|
* (unix is a trademark of Bell Laboratories)
|
|
|
|
*/
|
|
|
|
double stdf[26] = {
|
|
|
|
7.97, 1.35, 3.61, 4.78, 12.37, 2.01, 1.46, 4.49, 6.39, 0.04,
|
|
|
|
0.42, 3.81, 2.69, 5.92, 6.96, 2.91, 0.08, 6.63, 8.77, 9.68,
|
|
|
|
2.62, 0.81, 1.88, 0.23, 2.07, 0.06,
|
|
|
|
};
|
|
|
|
|
1996-05-27 08:50:53 +00:00
|
|
|
void printit();
|
|
|
|
|
1999-09-15 01:58:44 +00:00
|
|
|
int
|
|
|
|
main(argc, argv)
|
1994-09-04 04:03:31 +00:00
|
|
|
int argc;
|
|
|
|
char **argv;
|
|
|
|
{
|
1999-11-16 02:58:06 +00:00
|
|
|
int ch, dot, i, nread, winnerdot = 0;
|
|
|
|
char *inbuf;
|
1994-09-04 04:03:31 +00:00
|
|
|
int obs[26], try, winner;
|
|
|
|
|
1999-04-19 03:59:02 +00:00
|
|
|
/* revoke setgid privileges */
|
|
|
|
setgid(getgid());
|
|
|
|
|
1994-09-04 04:03:31 +00:00
|
|
|
if (argc > 1)
|
|
|
|
printit(argv[1]);
|
|
|
|
|
|
|
|
if (!(inbuf = malloc(LINELENGTH))) {
|
|
|
|
(void)fprintf(stderr, "caesar: out of memory.\n");
|
|
|
|
exit(1);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* adjust frequency table to weight low probs REAL low */
|
|
|
|
for (i = 0; i < 26; ++i)
|
|
|
|
stdf[i] = log(stdf[i]) + log(26.0 / 100.0);
|
|
|
|
|
|
|
|
/* zero out observation table */
|
|
|
|
bzero(obs, 26 * sizeof(int));
|
|
|
|
|
|
|
|
if ((nread = read(STDIN_FILENO, inbuf, LINELENGTH)) < 0) {
|
|
|
|
(void)fprintf(stderr, "caesar: %s\n", strerror(errno));
|
|
|
|
exit(1);
|
|
|
|
}
|
|
|
|
for (i = nread; i--;) {
|
1996-05-27 08:50:53 +00:00
|
|
|
ch = (unsigned char) inbuf[i];
|
|
|
|
if (isascii(ch)) {
|
|
|
|
if (islower(ch))
|
|
|
|
++obs[ch - 'a'];
|
|
|
|
else if (isupper(ch))
|
|
|
|
++obs[ch - 'A'];
|
|
|
|
}
|
1994-09-04 04:03:31 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* now "dot" the freqs with the observed letter freqs
|
|
|
|
* and keep track of best fit
|
|
|
|
*/
|
|
|
|
for (try = winner = 0; try < 26; ++try) { /* += 13) { */
|
|
|
|
dot = 0;
|
|
|
|
for (i = 0; i < 26; i++)
|
|
|
|
dot += obs[i] * stdf[(i + try) % 26];
|
|
|
|
/* initialize winning score */
|
|
|
|
if (try == 0)
|
|
|
|
winnerdot = dot;
|
|
|
|
if (dot > winnerdot) {
|
|
|
|
/* got a new winner! */
|
|
|
|
winner = try;
|
|
|
|
winnerdot = dot;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
for (;;) {
|
|
|
|
for (i = 0; i < nread; ++i) {
|
1996-05-27 08:50:53 +00:00
|
|
|
ch = (unsigned char) inbuf[i];
|
1994-09-04 04:03:31 +00:00
|
|
|
putchar(ROTATE(ch, winner));
|
|
|
|
}
|
|
|
|
if (nread < LINELENGTH)
|
|
|
|
break;
|
|
|
|
if ((nread = read(STDIN_FILENO, inbuf, LINELENGTH)) < 0) {
|
|
|
|
(void)fprintf(stderr, "caesar: %s\n", strerror(errno));
|
|
|
|
exit(1);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
exit(0);
|
|
|
|
}
|
|
|
|
|
1996-05-27 08:50:53 +00:00
|
|
|
void printit(arg)
|
1994-09-04 04:03:31 +00:00
|
|
|
char *arg;
|
|
|
|
{
|
1999-11-16 02:58:06 +00:00
|
|
|
int ch, rot;
|
1994-09-04 04:03:31 +00:00
|
|
|
|
|
|
|
if ((rot = atoi(arg)) < 0) {
|
|
|
|
(void)fprintf(stderr, "caesar: bad rotation value.\n");
|
|
|
|
exit(1);
|
|
|
|
}
|
|
|
|
while ((ch = getchar()) != EOF)
|
|
|
|
putchar(ROTATE(ch, rot));
|
|
|
|
exit(0);
|
|
|
|
}
|