##
# \file

# To each interface a set of caller functions exist, that take an instance
# of an object and then in turn call the implementation for the class of
# this object. If there is none within the class it looks into its
# parent class and so forth.
#
# This is somewhat similar to late binding in real OOP languages, but
# by far not so elaborated. This is not a real object oriented language
# and will surely never ever provide all features these have.
#
# That said it has proven very usefull for me to orgnize code and prevent
# code duplication.
#
# \author	Georg Hopp
#
# \copyright
# Copyright © 2014 Georg Hopp
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

. utils/file.sh

##
# Function calculates number of bit in a netmask
#
mask2cidr() {
	local NBITS=0
	local OLDIFS="${IFS}"
	IFS=.

	for DEC in $1
	do
		case ${DEC} in
			255) NBITS=$((NBITS+8));;
			254) NBITS=$((NBITS+7));;
			252) NBITS=$((NBITS+6));;
			248) NBITS=$((NBITS+5));;
			240) NBITS=$((NBITS+4));;
			224) NBITS=$((NBITS+3));;
			192) NBITS=$((NBITS+2));;
			128) NBITS=$((NBITS+1));;
			0);;
			*) NBITS=0; IFS="${OLDIFS}"; return 1
		esac
	done
	IFS="${OLDIFS}"
	${ECHO} "${NBITS}"
}

##
# Function calculates a netmask from number of bits
#
cidr2mask() {
	local I MASK=""
	local FULL_OCTETS=$((${1}/8))
	local PARTIAL_OCTET=$((${1}%8))

	for I in 0 1 2 3
	do
		if [ ${I} -lt ${FULL_OCTETS} ]
		then
			MASK="${MASK}255"
		elif [ ${I} -eq ${FULL_OCTETS} ]
		then
			MASK="${MASK}$((256-(1<<(8-${PARTIAL_OCTET}))))"
		else
			MASK="${MASK}0"
		fi  
		[ ${I} -lt 3 ] && MASK="${MASK}."
	done

	${ECHO} ${MASK}
}

# vim: set ts=4 sw=4: