1. Update manpage in view of the change of behavior I introduced in -r1.27.

The bounds are taken inclusive and -w %d doesn't change the output of
integer random sequences anymore.  This is the same behavior as that
of Linux and NetBSD, but differs from FreeBSD and OS X.

Issue reported by Philippe Meunier on misc@.

2 Fix a bug from the same commit observed by Otto: if the precision is 0,
values may be printed out of bounds.  Fall back to the old behavior if at
least one bound isn't an integer.

General agreement expressed by otto@, tedu@, jmc@, sobrado@
Help with checking other operating systems by sobrado@.

Manpage ok jmc@.
Bugfix discussed with otto@ on icb

2 files changed, 20 insertions, 52 deletions

diff --git a/usr.bin/jot/jot.1 b/usr.bin/jot/jot.1
index 7bd0675bf3c..b00f72407fb 100644
--- a/usr.bin/jot/jot.1
+++ b/usr.bin/jot/jot.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: jot.1,v 1.19 2016/01/04 23:21:28 schwarze Exp $
+.\"	$OpenBSD: jot.1,v 1.20 2016/07/17 04:04:46 tb Exp $
 .\"	$NetBSD: jot.1,v 1.2 1994/11/14 20:27:36 jtc Exp $
 .\"
 .\" Copyright (c) 1993
@@ -30,7 +30,7 @@
 .\"
 .\"	@(#)jot.1	8.1 (Berkeley) 6/6/93
 .\"
-.Dd $Mdocdate: January 4 2016 $
+.Dd $Mdocdate: July 17 2016 $
 .Dt JOT 1
 .Os
 .Sh NAME
@@ -225,41 +225,6 @@ specifying an integer format:
 .Bd -literal -offset indent
 $ jot -w %d 6 1 10 0.5
 .Ed
-.Pp
-For random sequences, the output format also influences the range
-and distribution of the generated numbers:
-.Bd -literal -offset indent
-$ jot -r 100000 1 3 | sort -n | uniq -c
-24950 1
-50038 2
-25012 3
-.Ed
-.Pp
-The values at the beginning and end of the interval
-are generated less frequently than the other values.
-There are several ways to solve this problem and generate evenly distributed
-integers:
-.Bd -literal -offset indent
-$ jot -r -p 0 100000 0.5 3.5 | sort -n | uniq -c
-33374 1
-33363 2
-33263 3
-
-$ jot -w %d -r 100000 1 4 | sort -n | uniq -c
-33306 1
-33473 2
-33221 3
-.Ed
-.Pp
-Note that with random sequences, all numbers generated will
-be smaller than the upper bound.
-The largest value generated will be a tiny bit smaller than
-the upper bound.
-For floating point formats, the value is rounded as described
-before being printed.
-For integer formats, the highest value printed will be one less
-than the requested upper bound, because the generated value will
-be truncated.
 .Sh EXAMPLES
 Print 21 evenly spaced numbers increasing from \-1 to 1:
 .Pp
@@ -280,7 +245,7 @@ comes after the character
 .Sq z
 in the ASCII character set):
 .Pp
-.Dl "$ jot \-r \-c 160 a { | rs \-g0 0 8"
+.Dl "$ jot \-r \-c 160 a z | rs \-g0 0 8"
 .Pp
 Infinitely many
 .Xr yes 1 Ns 's
diff --git a/usr.bin/jot/jot.c b/usr.bin/jot/jot.c
index e4fdade12f9..08da69f270b 100644
--- a/usr.bin/jot/jot.c
+++ b/usr.bin/jot/jot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: jot.c,v 1.27 2016/01/10 01:15:52 tb Exp $	*/
+/*	$OpenBSD: jot.c,v 1.28 2016/07/17 04:04:46 tb Exp $	*/
 /*	$NetBSD: jot.c,v 1.3 1994/12/02 20:29:43 pk Exp $	*/
 
 /*-
@@ -277,9 +277,6 @@ main(int argc, char *argv[])
 		if (prec > 9)	/* pow(10, prec) > UINT32_MAX */
 			errx(1, "requested precision too large");
 
-		while (prec-- > 0)
-			pow10 *= 10;
-
 		if (ender < begin) {
 			x = begin;
 			begin = ender;
@@ -287,16 +284,22 @@ main(int argc, char *argv[])
 		}
 		x = ender - begin;
 
-		/*
-		 * If pow10 * (ender - begin) is an integer, use
-		 * arc4random_uniform().
-		 */
-		use_unif = fmod(pow10 * (ender - begin), 1) == 0;
-		if (use_unif) {
-			uintx = pow10 * (ender - begin);
-			if (uintx >= UINT32_MAX)
-				errx(1, "requested range too large");
-			uintx++;
+		if (prec == 0 && (fmod(ender, 1) != 0 || fmod(begin, 1) != 0))
+			use_unif = 0;
+		else {
+			while (prec-- > 0)
+				pow10 *= 10;
+			/*
+			 * If pow10 * (ender - begin) is an integer, use
+			 * arc4random_uniform().
+			 */
+			use_unif = fmod(pow10 * (ender - begin), 1) == 0;
+			if (use_unif) {
+				uintx = pow10 * (ender - begin);
+				if (uintx >= UINT32_MAX)
+					errx(1, "requested range too large");
+				uintx++;
+			}
 		}
 
 		for (i = 1; i <= reps || infinity; i++) {