xref: /illumos-gate/usr/src/test/zfs-tests/include/math.shlib (revision d1e631af56641f21cde1f1efe3a9623ff9d6ee7c)
1#
2# This file and its contents are supplied under the terms of the
3# Common Development and Distribution License ("CDDL"), version 1.0.
4# You may only use this file in accordance with the terms of version
5# 1.0 of the CDDL.
6#
7# A full copy of the text of the CDDL should have accompanied this
8# source.  A copy of the CDDL is also available via the Internet at
9# http://www.illumos.org/license/CDDL.
10#
11
12#
13# Copyright (c) 2012 by Delphix. All rights reserved.
14#
15
16#
17# Return 0 if the percentage difference between $a and $b is $percent or
18# greater. Return 1 if the percentage is lower or if we would divide by
19# zero. For use like this:
20#
21# Do $action if the calculated percentage is greater or equal to that passed in:
22#	within_percent A B P && $action
23# Do $action if the calculated percentage is less than that passed in:
24#	within_percent A B P || $action
25#
26function within_percent
27{
28	typeset a=$1
29	typeset b=$1
30	typeset percent=$3
31
32	# Set $a or $b to $2 such that a >= b
33	[[ '1' = $($ECHO "if ($2 > $a) 1" | $BC) ]] && a=$2 || b=$2
34
35	# Prevent division by 0
36	[[ $a =~ [1-9] ]] || return 1
37
38	typeset p=$($ECHO "scale=2; $b * 100 / $a" | $BC)
39	log_note "Comparing $a and $b given $percent% (calculated: $p%)"
40	[[ '1' = $($ECHO "scale=2; if ($p >= $percent) 1" | $BC) ]] && return 0
41
42	return 1
43}
44