dna-encoding

elixir/dna-encoding/lib/dna.ex

@@ -0,0 +1,29 @@
+defmodule DNA do
+  def encode_nucleotide(?\s), do: 0b0000
+  def encode_nucleotide(?A), do: 0b0001
+  def encode_nucleotide(?C), do: 0b0010
+  def encode_nucleotide(?G), do: 0b0100
+  def encode_nucleotide(?T), do: 0b1000
+
+  def decode_nucleotide(0b0000), do: ?\s
+  def decode_nucleotide(0b0001), do: ?A
+  def decode_nucleotide(0b0010), do: ?C
+  def decode_nucleotide(0b0100), do: ?G
+  def decode_nucleotide(0b1000), do: ?T
+
+  def encode(dna), do: do_encode(dna)
+
+  defp do_encode(list, acc \\ <<0::size(0)>>)
+  defp do_encode([], acc), do: acc
+  defp do_encode([nucleotide | tail], acc) do
+    do_encode(tail, <<acc::bitstring, encode_nucleotide(nucleotide)::size(4)>>)
+  end
+
+  def decode(dna), do: do_decode(dna)
+
+  defp do_decode(list, acc \\ [])
+  defp do_decode(<<>>, acc), do: acc
+  defp do_decode(<<nucleotide::4, rest::bitstring>>, acc) do
+    do_decode(rest, acc ++ [decode_nucleotide(nucleotide)])
+  end
+end