From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-users-return-17074-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 24457 invoked by alias); 10 May 2012 15:12:46 -0000
Mailing-List: contact zsh-users-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Users List <zsh-users.zsh.org>
List-Post: <mailto:zsh-users@zsh.org>
List-Help: <mailto:zsh-users-help@zsh.org>
X-Seq: 17074
Received: (qmail 15245 invoked from network); 10 May 2012 15:12:44 -0000
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE
	autolearn=ham version=3.3.2
Received-SPF: none (ns1.primenet.com.au: domain at closedmail.com does not designate permitted sender hosts)
From: Bart Schaefer <schaefer@brasslantern.com>
Message-id: <120510081212.ZM14892@torch.brasslantern.com>
Date: Thu, 10 May 2012 08:12:12 -0700
In-reply-to: <20120510135934.00f00537@internecto.net>
Comments: In reply to Mark van Dijk <lists+zsh@internecto.net>
 "logical NOT" (May 10,  1:59pm)
References: <20120510135934.00f00537@internecto.net>
X-Mailer: OpenZMail Classic (0.9.2 24April2005)
To: zsh-users@zsh.org
Subject: Re: logical NOT
MIME-version: 1.0
Content-type: text/plain; charset=us-ascii

On May 10,  1:59pm, Mark van Dijk wrote:
}
} Then I wondered about how to let zsh "reverse" a binary number and came
} up with the logical NOT: simply flip each bit.

As others have noted, that gives you the number what might be described
as "upside down", rather than backward.

mac2bin() {
  setopt localoptions extendedglob
  print ${(l:8::0:)${${(s.:.)1}//(#b)(*)/$(([#2]$match))}#2\#}
}

reverse() {
  setopt localoptions noksharrays
  local i a
  a=( ${(s::)*} )
  for i in {$#a..1}; print -n -- $a[$i]
  print
}

torch% mac2bin AC:DE:48:00:00:80
00000000 00000000 00110000 00000000 00000000 01010000
torch% reverse $(mac2bin AC:DE:48:00:00:80)
00001010 00000000 00000000 00001100 00000000 00000000