+/* $NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $ */
+
/*
- * Copyright (c) 1989 The Regents of the University of California.
- * All rights reserved.
+ * 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.
* Stan King, John Eldridge, based on algorithm suggested by
* Bob Morris
* 29-Sep-82
+ * Roland Illig, 2005
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 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
+ * 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.
*
* SUCH DAMAGE.
*/
+#include <sys/cdefs.h>
#ifndef lint
-char copyright[] =
-"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
- All rights reserved.\n";
+__COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
+ The Regents of the University of California. All rights reserved.\n");
#endif /* not lint */
#ifndef lint
-static char sccsid[] = "@(#)caesar.c 5.4 (Berkeley) 6/1/90";
+#if 0
+static char sccsid[] = "@(#)caesar.c 8.1 (Berkeley) 5/31/93";
+#else
+__RCSID("$NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $");
+#endif
#endif /* not lint */
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <limits.h>
#include <math.h>
#include <stdio.h>
-#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
#include <unistd.h>
-#define LINELENGTH 2048
-#define ROTATE(ch, perm) \
- isupper(ch) ? ('A' + (ch - 'A' + perm) % 26) : \
- islower(ch) ? ('a' + (ch - 'a' + perm) % 26) : ch
+#define NCHARS (1 << CHAR_BIT)
+#define LETTERS (26)
/*
* letter frequencies (taken from some unix(tm) documentation)
* (unix is a trademark of Bell Laboratories)
*/
-double stdf[26] = {
+static const unsigned char upper[LETTERS] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+static const unsigned char lower[LETTERS] = "abcdefghijklmnopqrstuvwxyz";
+static double stdf[LETTERS] = {
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,
+ 2.62, 0.81, 1.88, 0.23, 2.07, 0.06
};
-main(argc, argv)
- int argc;
- char **argv;
+static unsigned char rottbl[NCHARS];
+
+
+static void
+init_rottbl(int rot)
+{
+ size_t i;
+
+ rot %= LETTERS;
+
+ for (i = 0; i < NCHARS; i++)
+ rottbl[i] = (unsigned char)i;
+
+ for (i = 0; i < LETTERS; i++)
+ rottbl[upper[i]] = upper[(i + rot) % LETTERS];
+
+ for (i = 0; i < LETTERS; i++)
+ rottbl[lower[i]] = lower[(i + rot) % LETTERS];
+}
+
+static void __attribute__((__noreturn__))
+printrot(const char *arg)
{
- extern int errno;
- register int ch, dot, i, nread, winnerdot;
- register char *inbuf;
- int obs[26], try, winner;
- char *malloc(), *strerror();
-
- if (argc > 1)
- printit(argv[1]);
-
- if (!(inbuf = malloc(LINELENGTH))) {
- (void)fprintf(stderr, "caesar: out of memory.\n");
- exit(1);
+ int ch;
+ long rot;
+ char *endp;
+
+ errno = 0;
+ rot = strtol(arg, &endp, 10);
+ if (*endp != '\0') {
+ errx(EXIT_FAILURE, "bad rotation value: %s", arg);
+ /* NOTREACHED */
+ }
+ if (errno == ERANGE || rot < 0 || rot > INT_MAX) {
+ errx(EXIT_FAILURE, "rotation value out of range: %s", arg);
+ /* NOTREACHED */
+ }
+ init_rottbl((int)rot);
+
+ while ((ch = getchar()) != EOF) {
+ if (putchar(rottbl[ch]) == EOF) {
+ err(EXIT_FAILURE, "writing to stdout");
+ /* NOTREACHED */
+ }
+ }
+ exit(EXIT_SUCCESS);
+ /* NOTREACHED */
+}
+
+int
+main(int argc, char **argv)
+{
+ ssize_t i, nread, ntotal;
+ double dot, winnerdot;
+ int try, winner;
+ unsigned char inbuf[2048];
+ unsigned int obs[NCHARS];
+
+ /* revoke setgid privileges */
+ (void)setgid(getgid());
+
+ if (argc > 1) {
+ printrot(argv[1]);
+ /* NOTREACHED */
}
/* 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);
+ for (i = 0; i < LETTERS; i++)
+ stdf[i] = log(stdf[i]) + log(LETTERS / 100.0);
/* zero out observation table */
- bzero(obs, 26 * sizeof(int));
+ (void)memset(obs, 0, sizeof(obs));
- if ((nread = read(STDIN_FILENO, inbuf, LINELENGTH)) < 0) {
- (void)fprintf(stderr, "caesar: %s\n", strerror(errno));
- exit(1);
- }
- for (i = nread; i--;) {
- ch = inbuf[i];
- if (islower(ch))
- ++obs[ch - 'a'];
- else if (isupper(ch))
- ++obs[ch - 'A'];
+ for (ntotal = 0; (size_t) ntotal < sizeof(inbuf); ntotal += nread) {
+ nread = read(STDIN_FILENO, &inbuf[ntotal],
+ sizeof(inbuf) - ntotal);
+ if (nread < 0) {
+ err(EXIT_FAILURE, "reading from stdin");
+ /* NOTREACHED */
+ }
+ if (nread == 0)
+ break;
}
+ for (i = 0; i < ntotal; i++)
+ obs[inbuf[i]]++;
+
/*
* 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) {
+ winner = 0;
+ winnerdot = 0.0;
+ for (try = 0; try < LETTERS; try++) {
+ dot = 0.0;
+ for (i = 0; i < LETTERS; i++)
+ dot += (obs[upper[i]] + obs[lower[i]])
+ * stdf[(i + try) % LETTERS];
+
+ if (try == 0 || dot > winnerdot) {
/* got a new winner! */
winner = try;
winnerdot = dot;
}
}
+ init_rottbl(winner);
- for (;;) {
- for (i = 0; i < nread; ++i) {
- ch = inbuf[i];
- putchar(ROTATE(ch, winner));
+ while (ntotal > 0) {
+ for (i = 0; i < ntotal; i++) {
+ if (putchar(rottbl[inbuf[i]]) == EOF) {
+ err(EXIT_FAILURE, "writing to stdout");
+ /* NOTREACHED */
+ }
}
- if (nread < LINELENGTH)
- break;
- if ((nread = read(STDIN_FILENO, inbuf, LINELENGTH)) < 0) {
- (void)fprintf(stderr, "caesar: %s\n", strerror(errno));
- exit(1);
+ if ((ntotal = read(STDIN_FILENO, inbuf, sizeof(inbuf))) < 0) {
+ err(EXIT_FAILURE, "reading from stdin");
+ /* NOTREACHED */
}
}
- exit(0);
-}
-
-printit(arg)
- char *arg;
-{
- register int ch, rot;
-
- 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);
+ exit(EXIT_FAILURE);
+ /* NOTREACHED */
}
git.ckatri.com / bsdgames-darwin.git / blobdiff