#!/bin/sh
#################################################################
#
#	@(#) d2x.sh (c) 2021 by H. Zuleger HZNET
#
#	convert integer values between different number systems
#
#	- run the script with option --install-script within the
#	  installation directory to create all the needed links
#
#	d2?	convert decimal to hexdecimal,octal,binary
#	x2?	convert hexadecimal to decimal,octal,binary
#	o2?	convert octal to hexadecimal,decimal,binary
#	b2?	convert binary to hexadecimal,decimal,octal
#
#	Apr 2022
#		- leading zeroes up to nibble, byte or word
#		  boundary added
#
#	Sep 2022	
#		- use of dc(1) to add the leading zeroes
#		- adding of double word boundary
#		- boundary changed to option -n -b -w and -d
#		- option -6 for IPv6 address parsing (uses x2?)
#		- option -s added for spacing of hex and binary output
#
#	Oct 2022
#		- fixed bug in option -6
#
#	Feb 2023
#		- option -4 added to parse IPv4 addresses (uses d2?)
#		- test if argument is an ip address
#
#################################################################
PATH=/bin:/usr/bin

# default is decimal
i=10
o=10
boundary=0
spacing=0

prog=`basename $0`

install()
{
	ns="b o d x"
	for from in $ns
	do
		for to in $ns
		do
			test $from = $to && continue

			new="${from}2${to}"
			test $prog != $new &&
				ln $prog $new
		done
	done
	exit
}

usage()
{
	test -n "$1" && echo "$1" 1>&2
	echo "usage: $prog [{-nibble|-byte|-word|-doubleword} [-s]] value [...]" 1>&2
	echo "usage: $prog [{-4|-6}] [-s] {ipv4address|ipv6address}" 1>&2
	exit 1
}

case $prog in
	b2?)	i=2	;;
	o2?)	i=8	;;
	d2?)	i=10	;;
	x2?)	i=16	;;
	*)	usage	;;
esac
case $prog in
	?2b)	o=2	;;
	?2o)	o=8	;;
	?2d)	o=10	;;
	?2x)	o=16	;;
	*)	usage	;;
esac

ip=0
while test $# -gt 0
do
	case $1 in
		--install-script|install-script)
			install
		;;
		-n*)	boundary=4
		;;
		-b*)	boundary=8
		;;
		-w*)	boundary=16
		;;
		-d*)	boundary=32
		;;
		-4)	ip=4
			i=10
			boundary=8
		;;
		-6)	ip=6
			i=16
			boundary=16
		;;
		-s*)	spacing=8
		;;
		-*)	usage "Illegal option $1"
		;;
		*)	break
		;;
	esac
	shift
done

test $# -lt 1 && usage "Missing base $i integer argument"

# parse argument if it looks like an ip address
case "$1" in
*.*)	i=10; ip=4; boundary=8
	;;
*:*)	i=16; ip=6; boundary=16
	;;
esac

# boundary makes sense on binary or hex output
if test $boundary -gt 0
then
	case $o in
	2)
	;;
	16)	boundary=`expr $boundary / 4`
		spacing=`expr $spacing / 2`
	;;
	*)	boundary=0
	;;
	esac
fi

if test $ip -eq 6	# split ipv6 address on colon blocks
then
	set `echo "$@" | tr -c "[0-9A-Fa-f]" " "`
elif test $ip -eq 4	# split ipv4 address on dots
then
	set `echo "$@" | tr -c "[0-9]" " "`
fi

{
	echo "$o o"
	echo "$i i"
	for v in "$@"
	do
		# echo "$v" | tr "[abcdef]" "[ABCDEF]" | tr -cd "[A-F0-9]"
		echo "$v" | tr "[abcdef]" "[ABCDEF]" | tr -c "[A-F0-9]" " "
		echo "p c"
	done
} |
dc |
if test $boundary -gt 0
then
	while read line
	do
		dc -e "$o o [d0<a]sb [1-d 0<a 0n]sa [$line] dZ $boundary r- lbx sX p" |
			tr -d '[\012\\]'	# long lines are wrapped by dc: remove it
		echo

		#zeroes=""
		#if test $boundary -gt 0
		#then
		#	chars=`echo $line | tr -d "\012" | wc -c`
		#	fill=`expr $boundary - \( $chars  % $boundary \)`
		#	test $debug && echo "$line, $chars, $fill" 1>&2
		#
		#	if test $fill -ne $boundary
		#	then
		#		zeroes=`yes 0 | sed ${fill}q | tr -d "\012"`
		#	fi
		#fi
		#echo $zeroes$line
	done |
	{ 
		tr -d "\012"
		echo
	} |
	if test $spacing -gt 0
	then
		pat=`echo "........" | cut -c1-$spacing`
		sed "s/$pat/& /g"
	else
		cat
	fi
else
	cat
fi