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|
module IPAddress
#
# =NAME
#
# IPAddress::Prefix
#
# =SYNOPSIS
#
# Parent class for Prefix32 and Prefix128
#
# =DESCRIPTION
#
# IPAddress::Prefix is the parent class for IPAddress::Prefix32
# and IPAddress::Prefix128, defining some modules in common for
# both the subclasses.
#
# IPAddress::Prefix shouldn't be accesses directly, unless
# for particular needs.
#
class Prefix
include Comparable
attr_reader :prefix
#
# Creates a new general prefix
#
def initialize(num)
@prefix = num.to_i
end
#
# Returns a string with the prefix
#
def to_s
"#@prefix"
end
alias_method :inspect, :to_s
#
# Returns the prefix
#
def to_i
@prefix
end
#
# Compare the prefix
#
def <=>(oth)
@prefix <=> oth.to_i
end
#
# Sums two prefixes or a prefix to a
# number, returns a Integer
#
def +(oth)
if oth.is_a? Integer
self.prefix + oth
else
self.prefix + oth.prefix
end
end
#
# Returns the difference between two
# prefixes, or a prefix and a number,
# as a Integer
#
def -(oth)
if oth.is_a? Integer
self.prefix - oth
else
(self.prefix - oth.prefix).abs
end
end
end # class Prefix
class Prefix32 < Prefix
IN4MASK = 0xffffffff
#
# Creates a new prefix object for 32 bits IPv4 addresses
#
# prefix = IPAddress::Prefix32.new 24
# #=> 24
#
def initialize(num)
unless (0..32).include? num
raise ArgumentError, "Prefix must be in range 0..32, got: #{num}"
end
super(num)
end
#
# Returns the length of the host portion
# of a netmask.
#
# prefix = Prefix32.new 24
#
# prefix.host_prefix
# #=> 8
#
def host_prefix
32 - @prefix
end
#
# Transforms the prefix into a string of bits
# representing the netmask
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix.bits
# #=> "11111111111111111111111100000000"
#
def bits
"%.32b" % to_u32
end
#
# Gives the prefix in IPv4 dotted decimal format,
# i.e. the canonical netmask we're all used to
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix.to_ip
# #=> "255.255.255.0"
#
def to_ip
[bits].pack("B*").unpack("CCCC").join(".")
end
#
# An array of octets of the IPv4 dotted decimal
# format
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix.octets
# #=> [255, 255, 255, 0]
#
def octets
to_ip.split(".").map{|i| i.to_i}
end
#
# Unsigned 32 bits decimal number representing
# the prefix
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix.to_u32
# #=> 4294967040
#
def to_u32
(IN4MASK >> host_prefix) << host_prefix
end
#
# Shortcut for the octecs in the dotted decimal
# representation
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix[2]
# #=> 255
#
def [](index)
octets[index]
end
#
# The hostmask is the contrary of the subnet mask,
# as it shows the bits that can change within the
# hosts
#
# prefix = IPAddress::Prefix32.new 24
#
# prefix.hostmask
# #=> "0.0.0.255"
#
def hostmask
[~to_u32].pack("N").unpack("CCCC").join(".")
end
#
# Creates a new prefix by parsing a netmask in
# dotted decimal form
#
# prefix = IPAddress::Prefix32::parse_netmask "255.255.255.0"
# #=> 24
#
def self.parse_netmask(netmask)
octets = netmask.split(".").map{|i| i.to_i}
num = octets.pack("C"*octets.size).unpack("B*").first.count "1"
return self.new(num)
end
end # class Prefix32 < Prefix
class Prefix128 < Prefix
#
# Creates a new prefix object for 128 bits IPv6 addresses
#
# prefix = IPAddress::Prefix128.new 64
# #=> 64
#
def initialize(num=128)
unless (0..128).include? num.to_i
raise ArgumentError, "Prefix must be in range 0..128, got: #{num}"
end
super(num.to_i)
end
#
# Transforms the prefix into a string of bits
# representing the netmask
#
# prefix = IPAddress::Prefix128.new 64
#
# prefix.bits
# #=> "1111111111111111111111111111111111111111111111111111111111111111"
# "0000000000000000000000000000000000000000000000000000000000000000"
#
def bits
"1" * @prefix + "0" * (128 - @prefix)
end
#
# Unsigned 128 bits decimal number representing
# the prefix
#
# prefix = IPAddress::Prefix128.new 64
#
# prefix.to_u128
# #=> 340282366920938463444927863358058659840
#
def to_u128
bits.to_i(2)
end
#
# Returns the length of the host portion
# of a netmask.
#
# prefix = Prefix128.new 96
#
# prefix.host_prefix
# #=> 32
#
def host_prefix
128 - @prefix
end
end # class Prefix123 < Prefix
end # module IPAddress
|
