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[src/trunk]: src/games/factor Add -h option to factor(6): duplicate factors a...
details: https://anonhg.NetBSD.org/src/rev/d82ed8ff3cde
branches: trunk
changeset: 827761:d82ed8ff3cde
user: rin <rin%NetBSD.org@localhost>
date: Sat Nov 11 23:48:44 2017 +0000
description:
Add -h option to factor(6): duplicate factors are printed in
"human-readable" form of x^n.
diffstat:
games/factor/factor.6 | 25 ++++++++++++++++++++-----
games/factor/factor.c | 50 +++++++++++++++++++++++++++++++++++---------------
2 files changed, 55 insertions(+), 20 deletions(-)
diffs (210 lines):
diff -r 32ac3732e54e -r d82ed8ff3cde games/factor/factor.6
--- a/games/factor/factor.6 Sat Nov 11 21:05:58 2017 +0000
+++ b/games/factor/factor.6 Sat Nov 11 23:48:44 2017 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: factor.6,v 1.13 2014/10/02 21:36:37 ast Exp $
+.\" $NetBSD: factor.6,v 1.14 2017/11/11 23:48:44 rin Exp $
.\"
.\" Copyright (c) 1989, 1993
.\" The Regents of the University of California. All rights reserved.
@@ -35,7 +35,7 @@
.\"
.\" By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
.\"
-.Dd May 15, 2010
+.Dd Nov 12, 2017
.Dt FACTOR 6
.Os
.Sh NAME
@@ -43,6 +43,7 @@
.Nd factor a number
.Sh SYNOPSIS
.Nm
+.Op Fl h
.Op Ar number ...
.Sh DESCRIPTION
The
@@ -54,15 +55,20 @@
.Pq prime
factors on a single line.
Factors are listed in ascending order, and are preceded by a space.
-If a factor divides a value more than once, it will be printed more than once.
+By default, if a factor divides a value more than once, it will be
+printed more than once.
.Pp
When
.Nm
-is invoked with one or more arguments, each argument will be factored.
+is invoked with one or more
+.Ar number
+arguments, each argument will be factored.
.Pp
When
.Nm
-is invoked with no arguments,
+is invoked with no
+.Ar number
+arguments,
.Nm
reads numbers, one per line, from standard input, until end of file or error.
Leading white-space and empty lines are ignored.
@@ -84,6 +90,15 @@
.Nm
is compiled without OpenSSL it is limited to the maximum value of
.Vt unsigned long .
+.Pp
+The following option is available:
+.Bl -tag -width flag
+.It Fl h
+If the
+.Fl h
+flag is specified, factors will be printed in "human-readable" format.
+If a factor x divides a value n (>1) times, it will appear as x^n.
+.El
.Sh DIAGNOSTICS
Out of range or invalid input results in
an appropriate error message to standard error.
diff -r 32ac3732e54e -r d82ed8ff3cde games/factor/factor.c
--- a/games/factor/factor.c Sat Nov 11 21:05:58 2017 +0000
+++ b/games/factor/factor.c Sat Nov 11 23:48:44 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: factor.c,v 1.27 2014/10/02 21:36:37 ast Exp $ */
+/* $NetBSD: factor.c,v 1.28 2017/11/11 23:48:44 rin Exp $ */
/*
* Copyright (c) 1989, 1993
@@ -42,7 +42,7 @@
#if 0
static char sccsid[] = "@(#)factor.c 8.4 (Berkeley) 5/4/95";
#else
-__RCSID("$NetBSD: factor.c,v 1.27 2014/10/02 21:36:37 ast Exp $");
+__RCSID("$NetBSD: factor.c,v 1.28 2017/11/11 23:48:44 rin Exp $");
#endif
#endif /* not lint */
@@ -52,15 +52,18 @@
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* usage:
- * factor [number] ...
+ * factor [-h] [number] ...
*
- * The form of the output is:
+ * By Default, the form of the output is:
*
* number: factor1 factor1 factor2 factor3 factor3 factor3 ...
*
* where factor1 <= factor2 <= factor3 <= ...
*
- * If no args are given, the list of numbers are read from stdin.
+ * If the -h flag is specified, the output is in "human-readable" format.
+ * Duplicate factors are printed in the form of x^n.
+ *
+ * If no number args are given, the list of numbers are read from stdin.
*/
#include <ctype.h>
@@ -103,7 +106,7 @@
static BN_CTX *ctx; /* just use a global context */
#endif
-static void pr_fact(BIGNUM *); /* print factors of a value */
+static void pr_fact(BIGNUM *, int); /* print factors of a value */
static void BN_print_dec_fp(FILE *, const BIGNUM *);
static void usage(void) __dead;
#ifdef HAVE_OPENSSL
@@ -132,7 +135,7 @@
main(int argc, char *argv[])
{
BIGNUM *val;
- int ch;
+ int ch, hflag;
char *p, buf[LINE_MAX]; /* > max number of digits. */
#ifdef HAVE_OPENSSL
@@ -142,8 +145,12 @@
if (val == NULL)
errx(1, "can't initialise bignum");
- while ((ch = getopt(argc, argv, "")) != -1)
+ hflag = 0;
+ while ((ch = getopt(argc, argv, "h")) != -1)
switch (ch) {
+ case 'h':
+ hflag = 1;
+ break;
case '?':
default:
usage();
@@ -166,7 +173,7 @@
errx(1, "negative numbers aren't permitted.");
if (BN_dec2bn(&val, buf) == 0)
errx(1, "%s: illegal numeric format.", argv[0]);
- pr_fact(val);
+ pr_fact(val, hflag);
}
/* Factor the arguments. */
else
@@ -175,7 +182,7 @@
errx(1, "numbers <= 1 aren't permitted.");
if (BN_dec2bn(&val, argv[0]) == 0)
errx(1, "%s: illegal numeric format.", argv[0]);
- pr_fact(val);
+ pr_fact(val, hflag);
}
exit(0);
}
@@ -188,15 +195,19 @@
* processing.
*
* Print the factors of the number, from the lowest to the highest.
- * A factor will be printed numtiple times if it divides the value
- * multiple times.
+ * By default, a factor will be printed numtiple times if it divides
+ * the value multiple times.
+ *
+ * If hflag is specified, duplicate factors are printed in "human-
+ * readable" form of x^n.
*
* Factors are printed with leading tabs.
*/
static void
-pr_fact(BIGNUM *val)
+pr_fact(BIGNUM *val, int hflag)
{
const uint64_t *fact; /* The factor found. */
+ int i;
/* Firewall - catch 0 and 1. */
if (BN_is_zero(val) || BN_is_one(val))
@@ -236,11 +247,20 @@
}
/* Divide factor out until none are left. */
+ i = 0;
do {
- printf(" %" PRIu64, *fact);
+ i++;
+ if (!hflag)
+ printf(" %" PRIu64, *fact);
BN_div_word(val, (BN_ULONG)*fact);
} while (BN_mod_word(val, (BN_ULONG)*fact) == 0);
+ if (hflag) {
+ printf(" %" PRIu64, *fact);
+ if (i > 1)
+ printf("^%d", i);
+ }
+
/* Let the user know we're doing something. */
fflush(stdout);
}
@@ -265,7 +285,7 @@
void
usage(void)
{
- fprintf(stderr, "usage: factor [value ...]\n");
+ fprintf(stderr, "usage: factor [-h] [value ...]\n");
exit (0);
}
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