Efficient binary strip?

bstrip.erl

-module(bstrip).

-export([bstrip/1, bstrip/2]).


bstrip(Bin) ->
    bstrip(Bin, both).

bstrip(Bin, left) ->
    blstrip(Bin);
bstrip(Bin, right) ->
    brstrip(Bin);
bstrip(Bin, both) ->
    blstrip(brstrip(Bin)).


blstrip(<<"\t", Bin/binary>>) ->
    blstrip(Bin);
blstrip(<<"\n", Bin/binary>>) ->
    blstrip(Bin);
blstrip(<<"\r", Bin/binary>>) ->
    blstrip(Bin);
blstrip(<<" ", Bin/binary>>) ->
    blstrip(Bin);
blstrip(Bin) ->
    brstrip(Bin).


brstrip(Bin) ->
    brstrip(Bin, size(Bin)-1).


brstrip(Bin, Size) ->
    NextSize = Size-1,
    case Bin of
        <<Bin2:Size/binary, " ">> ->
            brstrip(Bin2, NextSize);
        <<Bin2:Size/binary, "\r">> ->
            brstrip(Bin2, NextSize);
        <<Bin2:Size/binary, "\n">> ->
            brstrip(Bin2, NextSize);
        <<Bin2:Size/binary, "\t">> ->
            brstrip(Bin2, NextSize);
        StrippedBin ->
            StrippedBin
    end.


-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").

bstrip_test_() ->
    Tests = [<<"   foo bar">>,
             <<"   foo bar  ">>,
             <<"\r\n   \t foo bar">>,
             <<"   foo bar \r\n \t ">>],
    [{iolist_to_binary(io_lib:format("~p", [Input])),
      ?_assertEqual(<<"foo bar">>, bstrip(Input))} ||
        Input <- Tests].

-endif.