count_headers.escript

#!/usr/bin/env escript

main(Path) ->
    {ok, Fd} = file:open(Path, [binary, read, raw]),
    Count = count_headers(Fd),
    file:close(Fd),
    io:format("~s contains ~B headers.~n", [Path, Count]).

count_headers(Fd) ->
    count_headers(Fd, 0, 0).

count_headers(Fd, Offset, Acc) ->
    case file:pread(Fd, Offset, 1) of
        {ok, <<1>>} ->
            count_headers(Fd, Offset + 4096, Acc + 1);
        {ok, <<0>>} ->
            count_headers(Fd, Offset + 4096, Acc);
        eof ->
            Acc
    end.