i-bash/examples/functions/inetaddr

#
# inet2hex - Internet address conversion, dotted-decimal to hex
#
inet2hex ()
{
	local IFS

	IFS=.
	set -- $1

	if (( $# != 4 )); then
		echo "inet2hex: incorrect input format: $1" >&2
		echo "inet2hex: usage: inet2hex XX.XX.XX.XX" >&2
		return 2
	fi
  
	printf "0x%02x%02x%02x%02x\n" $1 $2 $3 $4
}

#
# hex2inet - Internet address conversion, hex to dotted-decimal
#
hex2inet ()
{
	local x1 x2 x3 x4
	local rev

	OPTIND=1
	while getopts "r" o
	do
		case "$o" in
		r)	rev=true;;
		*)	echo "hex2inet: usage: hex2inet [0x]XXXXXXXX" >&2 ; exit 2;;
		esac
	done
	shift $(( $OPTIND - 1 ))

	case "$1" in
	0x*)	h=${1#??} ;;
	*)	h=$1 ;;
	esac

	if (( ${#h} != 8 )); then
		echo "hex2inet: $h not in inet format" >&2
		echo "hex2inet: usage: hex2inet [0x]XXXXXXXX" >&2
		return 2
	fi

	x1=$(( 0x${h:0:2} ))
	x2=$(( 0x${h:2:2} ))
	x3=$(( 0x${h:4:2} ))
	x4=$(( 0x${h:6:2} ))

	if [ -z "$rev" ] ; then
		printf "%d.%d.%d.%d\n" $x1 $x2 $x3 $x4 
	else
		printf "%d.%d.%d.%d\n" $x4 $x3 $x2 $x1 
	fi
	return 0
}