decoder.ex

with() do
  field_27 = %{}
  {field_val, data} = ProtoDef.Type.Varint.decode_varint!(data)
  field_27 = Map.put(field_27, :itemDamage, field_val)
  {field_val, data} = with() do
    <<val::signed-integer-1 * 8, data::binary>> = data
    {val, data}
  end
  field_27 = Map.put(field_27, :scale, field_val)
  {field_val, data} = with() do
    {count, data} = ProtoDef.Type.Varint.decode_varint!(data)
    {elems, data} = Enum.reduce(1..count, {[], data}, fn _, {elems, data} ->
      {new_elem, data} = with() do
        field_6 = %{}
        {field_val, data} = with() do
          <<val::signed-integer-1 * 8, data::binary>> = data
          {val, data}
        end
        field_6 = Map.put(field_6, :directionAndType, field_val)
        {field_val, data} = with() do
          <<val::signed-integer-1 * 8, data::binary>> = data
          {val, data}
        end
        field_6 = Map.put(field_6, :x, field_val)
        {field_val, data} = with() do
          <<val::signed-integer-1 * 8, data::binary>> = data
          {val, data}
        end
        field_6 = Map.put(field_6, :y, field_val)
        {field_6, data}
      end
      {[new_elem | elems], data}
    end)
    {Enum.reverse(elems), data}
  end
  field_27 = Map.put(field_27, :icons, field_val)
  {field_val, data} = with() do
    <<val::signed-integer-1 * 8, data::binary>> = data
    {val, data}
  end
  field_27 = Map.put(field_27, :columns, field_val)
  {field_val, data} = case(field_27[:columns]) do
    ("0" -> {nil, data})
    (_ -> with() do
      <<val::signed-integer-1 * 8, data::binary>> = data
      {val, data}
    end)
  end
  field_27 = Map.put(field_27, :rows, field_val)
  {field_val, data} = case(field_27[:columns]) do
    ("0" -> {nil, data})
    (_ -> with() do
      <<val::signed-integer-1 * 8, data::binary>> = data
      {val, data}
    end)
  end
  field_27 = Map.put(field_27, :x, field_val)
  {field_val, data} = case(field_27[:columns]) do
    ("0" -> {nil, data})
    (_ -> with() do
      <<val::signed-integer-1 * 8, data::binary>> = data
      {val, data}
    end)
  end
  field_27 = Map.put(field_27, :y, field_val)
  {field_val, data} = case(field_27[:columns]) do
    ("0" -> {nil, data})
    (_ -> with() do
      {count, data} = ProtoDef.Type.Varint.decode_varint!(data)
      <<val::binary-size(count), data::binary>> = data
      {val, data}
    end)
  end
  field_27 = Map.put(field_27, :data, field_val)
  {field_27, data}
end

go with https://github.com/PrismarineJS/minecraft-data/blob/master/data/1.8/protocol.json#L1805