gistfile1.txt

%% @author <cb@opscode.com>

%% @doc Simple hex to binary and back, taken from comments by Steve Vinoski and others

-module(hex).
-author('<cb@opscode.com>').
-export([bin_to_hexstr/1,hexstr_to_bin/1]).

%% External API
bin_to_hexstr(Bin) ->
  lists:flatten([io_lib:format("~2.16.0B", [X]) ||
    X <- binary_to_list(Bin)]).

hexstr_to_bin(S) ->
  hexstr_to_bin(S, []).
hexstr_to_bin([], Acc) ->
  list_to_binary(lists:reverse(Acc));
hexstr_to_bin([X,Y|T], Acc) ->
  {ok, [V], []} = io_lib:fread("~16u", [X,Y]),
  hexstr_to_bin(T, [V | Acc]).