From ddd10e4c13c84751112cd07bf66d2737a94bbcbd Mon Sep 17 00:00:00 2001 From: Ole Tange Date: Wed, 28 Jun 2017 13:21:31 +0200 Subject: [PATCH] rand: Support from-to range. --- rand/rand | 48 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 44 insertions(+), 4 deletions(-) diff --git a/rand/rand b/rand/rand index 176ce9b..3dcf080 100755 --- a/rand/rand +++ b/rand/rand @@ -10,7 +10,7 @@ rand - Generate (pseudo-)random data =head1 SYNOPSIS -B +B [[I] I] =head1 DESCRIPTION @@ -22,6 +22,10 @@ faster (400 MB/s on hardware from 2013). The quality is lower as there are only 2^256 different tables (this is still around the number of atoms in the visible universe). +If I is given, numbers will be integers from 0 to I. + +If I is also given, numbers will be integers from I to I. + =head1 EXAMPLE @@ -30,9 +34,16 @@ Overwrite a harddisk with random data: rand >/dev/sda +=head1 EXAMPLE + +100 random numbers from 1000 to 1999: + + rand 1000 1999 | head -n 100 + + =head1 AUTHOR -Copyright (C) 2016 Ole Tange, +Copyright (C) 2017 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc. @@ -74,5 +85,34 @@ randfunc() { < /dev/zero openssl enc -aes-128-ctr -K $key -iv $iv 2>/dev/null } export -f randfunc -# Boost performance by running 1 per CPU core -eval parallel -u randfunc ::: {1..$(parallel --number-of-cores)} + +ints() { + from=$1 + to=$2 + # Allow up to 2^64 + perl -e '$diff='$to-$from'+1; + $factor = 2**64/$diff; + while(sysread(STDIN,$buf,65536)) { + print map { (int($_ / $factor) + '$from'),"\n" } unpack("Q*",$buf); + }' +} +export -f ints + +randints() { + randfunc | ints "$@" +} +export -f randints + +if [ "$1" == "" ] ; then + # Boost performance by running 1 per CPU core + eval parallel -u randfunc ::: {1..$(parallel --number-of-cores)} +else + # $1 set => numerical + if [ "$2" == "" ] ; then + # 0 .. $1 + eval parallel --lb randints 0 $1 ::: {1..$(parallel --number-of-cores)} + else + # $1 .. $2 + eval parallel --lb randints $1 $2 ::: {1..$(parallel --number-of-cores)} + fi +fi