PR/49850: Nikolai Lifanov: Document acronyms-o

[bsdgames-darwin.git] / caesar / caesar.c

diff --git a/caesar/caesar.c b/caesar/caesar.c
index 3423602f19a3f30f055d24dacfad25fe7ae9f845..1a6a8ea23f6dd961bcfba49d44c0e36d68f25cb6 100644 (file)
--- a/caesar/caesar.c
+++ b/caesar/caesar.c
@@ -1,4 +1,4 @@
-/*     $NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $       */
+/*     $NetBSD: caesar.c,v 1.22 2008/07/20 01:03:21 lukem Exp $        */
 
 /*
  * Copyright (c) 1989, 1993
@@ -40,19 +40,18 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
-       The Regents of the University of California.  All rights reserved.\n");
+__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
+ The Regents of the University of California.  All rights reserved.");
 #endif /* not lint */
 
 #ifndef lint
 #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 $");
+__RCSID("$NetBSD: caesar.c,v 1.22 2008/07/20 01:03:21 lukem Exp $");
 #endif
 #endif /* not lint */
 
-#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <limits.h>
@@ -60,7 +59,6 @@ __RCSID("$NetBSD: caesar.c,v 1.15 2005/05/23 23:02:30 rillig Exp $");
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <unistd.h>
 
 #define NCHARS                 (1 << CHAR_BIT)
 #define LETTERS                        (26)
@@ -85,7 +83,7 @@ init_rottbl(int rot)
 {
        size_t i;
 
-       rot %= LETTERS;
+       rot %= LETTERS;         /* prevent integer overflow */
 
        for (i = 0; i < NCHARS; i++)
                rottbl[i] = (unsigned char)i;
@@ -97,51 +95,58 @@ init_rottbl(int rot)
                rottbl[lower[i]] = lower[(i + rot) % LETTERS];
 }
 
-static void __attribute__((__noreturn__))
-printrot(const char *arg)
+static void
+print_file(void)
 {
        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");
+                       err(EXIT_FAILURE, "<stdout>");
                        /* NOTREACHED */
                }
        }
-       exit(EXIT_SUCCESS);
-       /* NOTREACHED */
 }
 
-int
-main(int argc, char **argv)
+static void
+print_array(const unsigned char *a, size_t len)
 {
-       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());
+       size_t i;
 
-       if (argc > 1) {
-               printrot(argv[1]);
-               /* NOTREACHED */
+       for (i = 0; i < len; i++) {
+               if (putchar(rottbl[a[i]]) == EOF) {
+                       err(EXIT_FAILURE, "<stdout>");
+                       /* NOTREACHED */
+               }
        }
+}
+
+static int
+get_rotation(const char *arg)
+{
+       long rot;
+       char *endp;
+
+       errno = 0;
+       rot = strtol(arg, &endp, 10);
+       if (errno == 0 && (arg[0] == '\0' || *endp != '\0'))
+               errno = EINVAL;
+       if (errno == 0 && (rot < 0 || rot > INT_MAX))
+               errno = ERANGE;
+       if (errno)
+               err(EXIT_FAILURE, "Bad rotation value `%s'", arg);
+       return (int)rot;
+}
+
+static void
+guess_and_rotate(void)
+{
+       unsigned char inbuf[2048];
+       unsigned int obs[NCHARS];
+       size_t i, nread;
+       double dot, winnerdot;
+       int try, winner;
+       int ch;
 
        /* adjust frequency table to weight low probs REAL low */
        for (i = 0; i < LETTERS; i++)
@@ -150,18 +155,13 @@ main(int argc, char **argv)
        /* zero out observation table */
        (void)memset(obs, 0, sizeof(obs));
 
-       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)
+       for (nread = 0; nread < sizeof(inbuf); nread++) {
+               if ((ch = getchar()) == EOF)
                        break;
+               inbuf[nread] = (unsigned char) ch;
        }
 
-       for (i = 0; i < ntotal; i++)
+       for (i = 0; i < nread; i++)
                obs[inbuf[i]]++;
 
        /*
@@ -182,20 +182,37 @@ main(int argc, char **argv)
                        winnerdot = dot;
                }
        }
+
        init_rottbl(winner);
+       print_array(inbuf, nread);
+       print_file();
+}
 
-       while (ntotal > 0) {
-               for (i = 0; i < ntotal; i++) {
-                       if (putchar(rottbl[inbuf[i]]) == EOF) {
-                               err(EXIT_FAILURE, "writing to stdout");
-                               /* NOTREACHED */
-                       }
-               }
-               if ((ntotal = read(STDIN_FILENO, inbuf, sizeof(inbuf))) < 0) {
-                       err(EXIT_FAILURE, "reading from stdin");
-                       /* NOTREACHED */
-               }
+int
+main(int argc, char **argv)
+{
+
+       if (argc == 1) {
+               guess_and_rotate();
+       } else if (argc == 2) {
+               init_rottbl(get_rotation(argv[1]));
+               print_file();
+       } else {
+               (void)fprintf(stderr, "usage: caesar [rotation]\n");
+               exit(EXIT_FAILURE);
+               /* NOTREACHED */
        }
-       exit(EXIT_FAILURE);
-       /* NOTREACHED */
+
+       if (ferror(stdin)) {
+               errx(EXIT_FAILURE, "<stdin>");
+               /* NOTREACHED */
+       }
+
+       (void)fflush(stdout);
+       if (ferror(stdout)) {
+               errx(EXIT_FAILURE, "<stdout>");
+               /* NOTREACHED */
+       }
+
+       return 0;
 }