tests/zfs-tests/include/math.shlib

   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 #
  26 function 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 }