update unix extra field

lib/dotzip.ex

@@ -1,8 +1,10 @@
 defmodule Dotzip do
   
   @moduledoc """
-  Elixir Implementation of ZIP File Format. https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT
-  """
+
+  Elixir Implementation of ZIP File Format.
+
+  """  
 
   def decode(data) do
     {:ok, local, rest} = Dotzip.LocalFileHeader.decode(data)

lib/dotzip/extra_field.ex

@@ -0,0 +1,9 @@
+defmodule Dotzip.ExtraField do
+
+  def encode() do
+  end
+
+  def decode() do
+  end
+  
+end

lib/dotzip/extra_field/unix.ex

@@ -0,0 +1,104 @@
+defmodule Dotzip.ExtraField.Unix do
+
+  @moduledoc """
+  
+  This module encode and decode Unix extra field defined in section
+  4.5.7 of the official documentation.
+
+  """
+
+  defstruct atime: 0, mtime: 0, uid: 0, gid: 0, var: 0
+  
+  defp tag() do
+    <<0x00, 0x0d>>
+  end
+  
+  defp encode_tag({:ok, data, buffer}) do
+    {:ok, data, <<tag::binary-size(2), buffer::bitstring>>}
+  end
+
+  defp encode_tsize({:ok, data, buffer}) do
+    s = byte_size(buffer)
+    {:ok, data, <<s::size(16), buffer::bitstring>>}
+  end
+
+  defp encode_atime({:ok, %{ :atime => atime } = data, buffer}) do
+    {:ok, data, <<atime::size(32), buffer::bitstring>>}
+  end
+
+  defp encode_mtime({:ok, %{ :mtime => mtime } = data, buffer}) do
+    {:ok, data, <<mtime::size(32), buffer::bitstring>>}
+  end
+
+  defp encode_uid({:ok, %{ :uid => uid } = data, buffer}) do
+    {:ok, data, <<uid::size(16), buffer::bitstring>>}
+  end
+
+  defp encode_gid({:ok, %{ :gid => gid } = data, buffer}) do
+    {:ok, data, <<gid::size(16), buffer::bitstring>>}
+  end
+
+  defp encode_var(data) do
+    {:ok, data, <<>>}
+  end
+
+  @doc """
+
+  Encode an Unix Extra field.
+
+  """
+  def encode(data) do
+    encode_var(data)
+    |> encode_gid()
+    |> encode_uid()
+    |> encode_mtime()
+    |> encode_atime()
+    |> encode_tsize()
+    |> encode_tag()
+  end
+
+  defp decode_tag(<<0x00, 0x0d, rest::bitstring>>) do
+    {:ok, %{}, rest}
+  end
+
+  defp decode_tsize({:ok, data, <<tsize::size(16), rest::bitstring>>}) do
+    {:ok, Map.put(data, :tsize, tsize), rest}
+  end
+
+  defp decode_atime({:ok, data, <<atime::size(32), rest::bitstring>>}) do
+    {:ok, Map.put(data, :atime, atime), rest}
+  end
+
+  defp decode_mtime({:ok, data, <<mtime::size(32), rest::bitstring>>}) do
+    {:ok, Map.put(data, :mtime, mtime), rest}
+  end
+
+  defp decode_uid({:ok, data, <<uid::size(16), rest::bitstring>>}) do
+    {:ok, Map.put(data, :uid, uid), rest}
+  end
+
+  defp decode_gid({:ok, data, <<gid::size(16), rest::bitstring>>}) do
+    {:ok, Map.put(data, :gid, gid ), rest}
+  end
+
+  defp decode_var({:ok, data, rest}) do
+    {:ok, data, rest}
+  end
+
+  @doc """
+
+  Decode an Unix Extra field.
+
+  """
+  
+  def decode(bitstring) do
+    decode_tag(bitstring)
+    |> decode_tsize()
+    |> decode_atime()
+    |> decode_mtime()
+    |> decode_uid()
+    |> decode_gid()
+    |> decode_var()
+  end
+
+end

lib/dotzip64.ex

@@ -0,0 +1,10 @@
+defmodule Dotzip64 do
+  
+  @moduledoc """
+
+  Elixir Implementation of ZIP64 File Format.
+
+  """ 
+  
+end
+