Add support IPAddr class

json.gemspec

@@ -37,6 +37,7 @@ Gem::Specification.new do |s|
     "lib/json/add/date.rb",
     "lib/json/add/date_time.rb",
     "lib/json/add/exception.rb",
+    "lib/json/add/ipaddr.rb",
     "lib/json/add/ostruct.rb",
     "lib/json/add/range.rb",
     "lib/json/add/rational.rb",

json_pure.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |s|
     "lib/json/add/date.rb".freeze,
     "lib/json/add/date_time.rb".freeze,
     "lib/json/add/exception.rb".freeze,
+    "lib/json/add/ipaddr.rb".freeze,
     "lib/json/add/ostruct.rb".freeze,
     "lib/json/add/range.rb".freeze,
     "lib/json/add/rational.rb".freeze,

lib/json.rb

@@ -400,6 +400,7 @@
 # - Date: <tt>require 'json/add/date'</tt>
 # - DateTime: <tt>require 'json/add/date_time'</tt>
 # - Exception: <tt>require 'json/add/exception'</tt>
+# - IPAddr: <tt>require 'json/add/ipaddr'</tt>
 # - OpenStruct: <tt>require 'json/add/ostruct'</tt>
 # - Range: <tt>require 'json/add/range'</tt>
 # - Rational: <tt>require 'json/add/rational'</tt>
@@ -451,6 +452,13 @@
 #   ruby1 = JSON.parse(json, create_additions: true) # Another message
 #   ruby1.class # RuntimeError
 #
+# \IPAddr:
+#   require 'json/add/ipaddr'
+#   ruby0 = IPAddr.new('127.0.0.1') # #<IPAddr: IPv4:127.0.0.1/255.255.255.255>
+#   json = JSON.generate(ruby0) # {"json_class":"IPAddr","a":127.0.0.1,"p":32}
+#   ruby1 = JSON.parse(json, create_additions: true) # #<IPAddr: IPv4:127.0.0.1/255.255.255.255>
+#   ruby1.class # IPAddr
+#
 # \OpenStruct:
 #   require 'json/add/ostruct'
 #   ruby0 = OpenStruct.new(name: 'Matz', language: 'Ruby') # #<OpenStruct name="Matz", language="Ruby">

lib/json/add/core.rb

@@ -5,6 +5,7 @@
 require 'json/add/date'
 require 'json/add/date_time'
 require 'json/add/exception'
+require 'json/add/ipaddr'
 require 'json/add/range'
 require 'json/add/regexp'
 require 'json/add/struct'

lib/json/add/ipaddr.rb

@@ -0,0 +1,57 @@
+#frozen_string_literal: false
+unless defined?(::JSON::JSON_LOADED) and ::JSON::JSON_LOADED
+  require 'json'
+end
+require 'ipaddr'
+
+class IPAddr
+
+  # Deserializes JSON string by constructing new IPAddr object with address
+  # <tt>a</tt> and prefix <tt>p</tt> serialized with <tt>to_json</tt>
+  def self.json_create(object)
+    addr = IPAddr.new(object['a'])
+    addr.mask(object['p'])
+    addr
+  end
+
+  # Returns a hash, that will be turned into a JSON object and represent this
+  # object.
+  def as_json(*)
+    if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.5.0")
+      prefix = prefixlen
+    else
+      prefix = self.prefix
+    end
+
+    {
+      JSON.create_id => self.class.name,
+      'a' => to_s,
+      'p' => prefix,
+    }
+  end
+
+  # Stores class name (IPAddr) with address <tt>a</tt> and prefix
+  # <tt>p</tt> as JSON string
+  def to_json(*args)
+    as_json.to_json(*args)
+  end
+
+  # for ruby version <= 2.4
+  def prefixlen
+    case @family
+    when Socket::AF_INET
+      n = IN4MASK ^ @mask_addr
+      i = 32
+    when Socket::AF_INET6
+      n = IN6MASK ^ @mask_addr
+      i = 128
+    else
+      raise AddressFamilyError, "unsupported address family"
+    end
+    while n.positive?
+      n >>= 1
+      i -= 1
+    end
+    i
+  end
+end

tests/json_addition_test.rb

@@ -7,6 +7,7 @@
 require 'json/add/ostruct'
 require 'json/add/set'
 require 'date'
+require 'ipaddr'
 
 class JSONAdditionTest < Test::Unit::TestCase
   include JSON
@@ -196,4 +197,10 @@ def test_set
     s = Set.new([:a, :b, :c, :a])
     assert_equal s, JSON.parse(JSON(s), :create_additions => true)
   end
+
+  def test_ipaddr
+    assert_equal IPAddr.new('127.0.0.1'), parse(JSON(IPAddr.new('127.0.0.1')), :create_additions => true)
+    assert_equal IPAddr.new('192.0.2.0/24'), parse(JSON(IPAddr.new('192.0.2.0/24')), :create_additions => true)
+    assert_equal IPAddr.new('2001:db8::/48'), parse(JSON(IPAddr.new('2001:db8::/48')), :create_additions => true)
+  end
 end