Openflow parser

lib/openflow/utils.ex

@@ -0,0 +1,73 @@
+defmodule Openflow.Utils do
+  import Bitwise
+
+  def int_to_flags(acc, int, [{type, flagint}|rest]) when (int &&& flagint) == flagint do
+    int_to_flags([type|acc], int, rest)
+  end
+  def int_to_flags(acc, int, [_h|rest]) do
+    int_to_flags(acc, int, rest)
+  end
+  def int_to_flags(acc, _int, []), do: Enum.reverse(acc)
+
+  def flags_to_int(acc, [], _enum), do: acc
+  def flags_to_int(acc0, [flag|rest], enum) do
+    acc = acc0 ||| Keyword.get(enum, flag, 0)
+    flags_to_int(acc, rest, enum)
+  end
+
+  def to_hex_string(binary), do: datapath_id(binary)
+
+  def padding(length, padding) do
+    case (padding - rem(length, padding)) do
+      ^padding -> 0
+      pad_len  -> pad_len
+    end
+  end
+
+  def pad_length(length, width) do
+    rem((width - rem(length, width)), width)
+  end
+
+  def decode_string(binary) do
+    String.trim_trailing(binary, <<0>>)
+  end
+
+  def encode_string(binary, length) do
+    String.pad_trailing(binary, length, <<0>>)
+  end
+
+  def get_enum(int, type) when is_integer(int) do
+    try do
+      Openflow.Enums.to_atom(int, type)
+    catch
+      :bad_enum -> int
+    end
+  end
+  def get_enum(int, type) do
+    try do
+      Openflow.Enums.to_int(int, type)
+    catch
+      :bad_enum -> int
+    end
+  end
+
+  # private functions
+
+  defp datapath_id(binary) do
+    binary
+    |> split_to_hex_string
+    |> Enum.join("")
+    |> String.downcase
+  end
+
+  defp split_to_hex_string(binary) do
+    for <<int <- binary>>, do: integer_to_hex(int)
+  end
+
+  defp integer_to_hex(int) do
+    case Integer.to_string(int, 16) do
+      <<d>> -> <<48, d>>
+      dd    -> dd
+    end
+  end
+end