antl_utils

defmodule AntlUtils.Elixir.String do
  @alphabets %{
    62 => "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
    64 => "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
  }

  @spec to_integer(binary, 62 | 64) :: integer
  def to_integer(string, base) when is_binary(string) and base in [62, 64] do
    String.codepoints(string)
    |> Enum.reduce(0, fn letter, acc ->
      acc * base + (:binary.match(Map.get(@alphabets, base), letter) |> elem(0))
    end)
  end
end