%%% @doc Some simple parsing routines.

-module(elli_ws_http).

-export([tokens/1]).


-define(IS_TOKEN_SEP(C), (C =:= $, orelse C =:= $\s orelse C=:= $\t)).


%% @doc Parse tokens
-spec tokens(binary() | [binary() | [binary() | list()]]) -> [bitstring()].
tokens(L) when is_list(L) ->
    lists:flatten([tokens(V) || V <- L]);
tokens(Header) when is_binary(Header) ->
    parse_before(Header, []).


parse_before(<<>>, Acc) ->
    lists:reverse(Acc);
parse_before(<< C, Rest/bits >>, Acc) when ?IS_TOKEN_SEP(C) ->
    parse_before(Rest, Acc);
parse_before(Buffer, Acc) ->
    parse(Buffer, Acc, <<>>).


parse(<<>>, Acc, <<>>) ->
    lists:reverse(Acc);
parse(<<>>, Acc, Token) ->
    lists:reverse([Token|Acc]);
parse(<<C, Rest/bits>>, Acc, Token) when ?IS_TOKEN_SEP(C) ->
    parse_before(Rest, [Token|Acc]);
parse(<<C, Rest/bits>>, Acc, Token) ->
    parse(Rest, Acc, <<Token/binary, (elli_bstr:lchr(C))>>).