Add allocate() method

The allocate() method allows to use an IPAddress::IPv4 or ::IPv6 object
to allocate individual host addresses so that the IPAddress object
tracks the state of which address was previously allocated.

Example:

  ip = IPAddress("10.0.0.0/24")
  ip.allocate
    #=> "10.0.0.1/24"
  ip.allocate
    #=> "10.0.0.2/24"

There is support for both IPv4 and IPv6 with full test coverage.

2 files changed, 48 insertions, 0 deletions

diff --git a/test/ipaddress/ipv4_test.rb b/test/ipaddress/ipv4_test.rb
index 19264e2..df60bb1 100644
--- a/test/ipaddress/ipv4_test.rb
+++ b/test/ipaddress/ipv4_test.rb
@@ -595,6 +595,30 @@ class IPv4Test < Minitest::Test
     assert_equal "192.168.200.0/24", ip.to_string
   end
 
+  def test_allocate_addresses
+    ip = @klass.new("10.0.0.0/24")
+    ip1 = ip.allocate
+    ip2 = ip.allocate
+    ip3 = ip.allocate
+    assert_equal "10.0.0.1/24", ip1.to_string
+    assert_equal "10.0.0.2/24", ip2.to_string
+    assert_equal "10.0.0.3/24", ip3.to_string
+  end
+
+  def test_allocate_can_skip_addresses
+    ip = @klass.new("10.0.0.0/24")
+    ip1 = ip.allocate(2)
+    assert_equal "10.0.0.3/24", ip1.to_string
+  end
+
+  def test_allocate_will_raise_stopiteration
+    ip = @klass.new("10.0.0.0/30")
+    ip.allocate(3)
+    assert_raises (StopIteration) do
+      ip.allocate
+    end
+  end
+
 end # class IPv4Test
 
   
diff --git a/test/ipaddress/ipv6_test.rb b/test/ipaddress/ipv6_test.rb
index 7eaa765..3990129 100644
--- a/test/ipaddress/ipv6_test.rb
+++ b/test/ipaddress/ipv6_test.rb
@@ -234,6 +234,30 @@ class IPv6Test < Minitest::Test
     assert_equal expected, arr
   end
 
+  def test_allocate_addresses
+    ip = @klass.new("2001:db8::4/125")
+    ip1 = ip.allocate
+    ip2 = ip.allocate
+    ip3 = ip.allocate
+    assert_equal "2001:db8::1", ip1.compressed
+    assert_equal "2001:db8::2", ip2.compressed
+    assert_equal "2001:db8::3", ip3.compressed
+  end
+
+  def test_allocate_can_skip_addresses
+    ip = @klass.new("2001:db8::4/125")
+    ip1 = ip.allocate(2)
+    assert_equal "2001:db8::3", ip1.compressed
+  end
+
+  def test_allocate_will_raise_stopiteration
+    ip = @klass.new("2001:db8::4/125")
+    ip.allocate(6)
+    assert_raises (StopIteration) do
+      ip.allocate
+    end
+  end
+
   def test_method_compare
     ip1 = @klass.new("2001:db8:1::1/64")
     ip2 = @klass.new("2001:db8:2::1/64")