### Copyright 2018 Pixar

###
###    Licensed under the Apache License, Version 2.0 (the "Apache License")
###    with the following modification; you may not use this file except in
###    compliance with the Apache License and the following modification to it:
###    Section 6. Trademarks. is deleted and replaced with:
###
###    6. Trademarks. This License does not grant permission to use the trade
###       names, trademarks, service marks, or product names of the Licensor
###       and its affiliates, except as required to comply with Section 4(c) of
###       the License and to reproduce the content of the NOTICE file.
###
###    You may obtain a copy of the Apache License at
###
###        http://www.apache.org/licenses/LICENSE-2.0
###
###    Unless required by applicable law or agreed to in writing, software
###    distributed under the Apache License with the above modification is
###    distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
###    KIND, either express or implied. See the Apache License for the specific
###    language governing permissions and limitations under the Apache License.
###
###

############################################
### A few augmentations to IPAddr handling.
###
class IPAddr

  ### Convert starting and ending IPv4 IP addresses (either Strings or IPAddrs)
  ### into a single masked IPv4 IPAddr
  ###
  ### @param starting[Strings, IPAddr] the starting IP address
  ###
  ### @param ending[Strings, IPAddr] the ending IP address
  ###
  ### @return [IPAddr] the IP address range represented as a masked IPv4 address
  ###
  ### @example
  ###   IPAddr.jss_masked_v4addr '10.0.0.0', '10.0.0.255' # => #<IPAddr: IPv4:10.0.0.0/255.255.255.0>
  ###
  def self.jss_masked_v4addr(starting,ending)
    IPAddr.new "#{starting}/#{self.jss_cidr_from_ends(starting,ending)}"
  end #self.jss_masked_v4addr(starting,ending)

  ### Given starting and ending IPv4 IP addresses (either Strings or IPAddrs)
  ### return the CIDR notation routing prefix mask
  ###
  ### @param starting[Strings, IPAddr] the starting IP address
  ###
  ### @param ending[Strings, IPAddr] the ending IP address
  ###
  ### @return [FixNum] the CIDR notation routing prefix mask
  ###
  ### @example
  ###   IPAddr.jss_cidr_from_ends '10.0.0.0', '10.0.0.255' # => 24
  ###
  def self.jss_cidr_from_ends(starting,ending)

    starting = IPAddr.new(starting) unless starting.kind_of? IPAddr
    ending = IPAddr.new(ending) unless ending.kind_of? IPAddr

    ### how many possible addresses in the range?
    num_addrs =  ending.to_i - starting.to_i + 1

    ### convert the number of possible addresses to
    ### binary then subtract the number of bits from
    ### the full length of an IPv4 addr
    ### (32 bits) and that gives the CIDR prefix
    return 32 - num_addrs.to_s(2).length + 1

  end #self.get_cidr(starting,ending)

  ### Convert a starting address (either String or IPAddr) and a
  ### CIDR notation routing prefix mask into the IPv4 address
  ### of at the end of the range of addresses.
  ###
  ### @param starting[Strings, IPAddr] the starting IP address
  ###
  ### @param cidr[FixNum] the CIDR mask
  ###
  ### @return [IPAddr] the ending IP address of the range.
  ###
  ### @example
  ###   IPAddr.jss_ending_address '10.0.0.0', 24 # => #<IPAddr: IPv4:10.0.0.255>
  ###
  def self.jss_ending_address(starting, cidr)
    IPAddr.new( "#{starting}/#{cidr}").to_range.max
  end # ending_address

end # Class IPAddr
