anchor.diff:  
   -define(PERCENT, 37).  % $\%
   -define(FULLSTOP, 46). % $\.
  +-define(LBRACE, 91). % $\[.
  +-define(RBRACE, 93). % $\].
   -define(IS_HEX(C), ((C >= $0 andalso C =< $9) orelse
                       (C >= $a andalso C =< $f) orelse
                       (C >= $A andalso C =< $F))).
  
positive.code: %%      is not safe. safe relative paths can be joined with an absolute path
  %%      and will result in a subdirectory of the absolute path.
  safe_relative_path("/" ++ _) ->
      undefined;
  safe_relative_path(P) ->
      safe_relative_path(P, []).
  
  safe_relative_path("", Acc) ->
      case Acc of
          [] ->
              "";
          _ ->
              string:join(lists:reverse(Acc), "/")
      end;
  safe_relative_path(P, Acc) ->
      case partition(P, "/") of
          {"", "/", _} ->
              %% /foo or foo//bar
              undefined;
          {"..", _, _} when Acc =:= [] ->
              undefined;
          {"..", _, Rest} ->
              safe_relative_path(Rest, tl(Acc));
          {Part, "/", ""} ->
              safe_relative_path("", ["", Part | Acc]);
          {Part, _, Rest} ->
              safe_relative_path(Rest, [Part | Acc])
      end.
  
  %% @spec shell_quote(string()) -> string()
  %% @doc Quote a string according to UNIX shell quoting rules, returns a string
  %%      surrounded by double quotes.
  shell_quote(L) ->
      shell_quote(L, [$\"]).
  
  %% @spec cmd_port([string()], Options) -> port()
  %% @doc open_port({spawn, mochiweb_util:cmd_string(Argv)}, Options).
  cmd_port(Argv, Options) ->
      open_port({spawn, cmd_string(Argv)}, Options).
  
  %% @spec cmd([string()]) -> string()
  %% @doc os:cmd(cmd_string(Argv)).
  cmd(Argv) ->
      os:cmd(cmd_string(Argv)).
  
  %% @spec cmd_string([string()]) -> string()
  %% @doc Create a shell quoted command string from a list of arguments.
  cmd_string(Argv) ->
      join([shell_quote(X) || X <- Argv], " ").
  
  %% @spec join([string()], Separator) -> string()
  %% @doc Join a list of strings together with the given separator
  %%      string or char.
  join([], _Separator) ->
      [];
  join([S], _Separator) ->
      lists:flatten(S);
  join(Strings, Separator) ->
      lists:flatten(revjoin(lists:reverse(Strings), Separator, [])).
  
  revjoin([], _Separator, Acc) ->
      Acc;
  revjoin([S | Rest], Separator, []) ->
      revjoin(Rest, Separator, [S]);
  revjoin([S | Rest], Separator, Acc) ->
      revjoin(Rest, Separator, [S, Separator | Acc]).
  
  %% @spec quote_plus(atom() | integer() | float() | string() | binary()) -> string()
  %% @doc URL safe encoding of the given term.
  quote_plus(Atom) when is_atom(Atom) ->
      quote_plus(atom_to_list(Atom));
  quote_plus(Int) when is_integer(Int) ->
      quote_plus(integer_to_list(Int));
  quote_plus(Binary) when is_binary(Binary) ->
      quote_plus(binary_to_list(Binary));
  quote_plus(Float) when is_float(Float) ->
      quote_plus(mochinum:digits(Float));
  quote_plus(String) ->
      quote_plus(String, []).
  
  quote_plus([], Acc) ->
      lists:reverse(Acc);
  quote_plus([C | Rest], Acc) when ?QS_SAFE(C) ->
      quote_plus(Rest, [C | Acc]);
  quote_plus([$\s | Rest], Acc) ->
      quote_plus(Rest, [$+ | Acc]);
  quote_plus([C | Rest], Acc) ->
      <<Hi:4, Lo:4>> = <<C>>,
      quote_plus(Rest, [hexdigit(Lo), hexdigit(Hi), ?PERCENT | Acc]).
  
  %% @spec urlencode([{Key, Value}]) -> string()
  %% @doc URL encode the property list.
  urlencode(Props) ->
      RevPairs = lists:foldl(fun ({K, V}, Acc) ->
                                     [[quote_plus(K), $=, quote_plus(V)] | Acc]
                             end, [], Props),
      lists:flatten(revjoin(RevPairs, $&, [])).
  
  %% @spec parse_qs(string() | binary()) -> [{Key, Value}]
  %% @doc Parse a query string or application/x-www-form-urlencoded.
  parse_qs(Binary) when is_binary(Binary) ->
      parse_qs(binary_to_list(Binary));
  parse_qs(String) ->
      parse_qs(String, []).
  
  parse_qs([], Acc) ->
      lists:reverse(Acc);
  parse_qs(String, Acc) ->
      {Key, Rest} = parse_qs_key(String),
      {Value, Rest1} = parse_qs_value(Rest),
      parse_qs(Rest1, [{Key, Value} | Acc]).
  
  parse_qs_key(String) ->
      parse_qs_key(String, []).
  
  parse_qs_key([], Acc) ->
      {qs_revdecode(Acc), ""};
  parse_qs_key([$= | Rest], Acc) ->
      {qs_revdecode(Acc), Rest};
  parse_qs_key(Rest=[$; | _], Acc) ->
      {qs_revdecode(Acc), Rest};
  parse_qs_key(Rest=[$& | _], Acc) ->
      {qs_revdecode(Acc), Rest};
  parse_qs_key([C | Rest], Acc) ->
      parse_qs_key(Rest, [C | Acc]).
  
  parse_qs_value(String) ->
      parse_qs_value(String, []).
  
  parse_qs_value([], Acc) ->
      {qs_revdecode(Acc), ""};
  parse_qs_value([$; | Rest], Acc) ->
      {qs_revdecode(Acc), Rest};
  parse_qs_value([$& | Rest], Acc) ->
      {qs_revdecode(Acc), Rest};
  parse_qs_value([C | Rest], Acc) ->
      parse_qs_value(Rest, [C | Acc]).
  
  %% @spec unquote(string() | binary()) -> string()
  %% @doc Unquote a URL encoded string.
  unquote(Binary) when is_binary(Binary) ->
      unquote(binary_to_list(Binary));
  unquote(String) ->
      qs_revdecode(lists:reverse(String)).
  
  qs_revdecode(S) ->
      qs_revdecode(S, []).
  
  qs_revdecode([], Acc) ->
      Acc;
  qs_revdecode([$+ | Rest], Acc) ->
      qs_revdecode(Rest, [$\s | Acc]);
  qs_revdecode([Lo, Hi, ?PERCENT | Rest], Acc) when ?IS_HEX(Lo), ?IS_HEX(Hi) ->
      qs_revdecode(Rest, [(unhexdigit(Lo) bor (unhexdigit(Hi) bsl 4)) | Acc]);
  qs_revdecode([C | Rest], Acc) ->
      qs_revdecode(Rest, [C | Acc]).
  
  %% @spec urlsplit(Url) -> {Scheme, Netloc, Path, Query, Fragment}
  %% @doc Return a 5-tuple, does not expand % escapes. Only supports HTTP style
  %%      URLs.
  urlsplit(Url) ->
      {Scheme, Url1} = urlsplit_scheme(Url),
      {Netloc, Url2} = urlsplit_netloc(Url1),
      {Path, Query, Fragment} = urlsplit_path(Url2),
      {Scheme, Netloc, Path, Query, Fragment}.
  
  urlsplit_scheme(Url) ->
      urlsplit_scheme(Url, []).
  
  urlsplit_scheme([], Acc) ->
      {"", lists:reverse(Acc)};
  urlsplit_scheme(":" ++ Rest, Acc) ->
      {string:to_lower(lists:reverse(Acc)), Rest};
  urlsplit_scheme([C | Rest], Acc) ->
      urlsplit_scheme(Rest, [C | Acc]).
  
  urlsplit_netloc("//" ++ Rest) ->
      urlsplit_netloc(Rest, []);
  urlsplit_netloc(Path) ->
      {"", Path}.
  
  urlsplit_netloc(Rest=[C | _], Acc) when C =:= $/; C =:= $?; C =:= $# ->
      {lists:reverse(Acc), Rest};
  urlsplit_netloc([C | Rest], Acc) ->
      urlsplit_netloc(Rest, [C | Acc]).
  
  
  %% @spec path_split(string()) -> {Part, Rest}
  
negative.code: %%      path_split("foo/bar") = {"foo", "bar"},
  %%      path_split("/foo/bar") = {"", "foo/bar"}.
  path_split(S) ->
    path_split(S, []).
  
  path_split("", Acc) ->
    {lists:reverse(Acc), ""};
  path_split("/" ++ Rest, Acc) ->
    {lists:reverse(Acc), Rest};
  path_split([C | Rest], Acc) ->
    path_split(Rest, [C | Acc]).
  
  
  %% @spec urlunsplit({Scheme, Netloc, Path, Query, Fragment}) -> string()
  %% @doc Assemble a URL from the 5-tuple. Path must be absolute.
  urlunsplit({Scheme, Netloc, Path, Query, Fragment}) ->
    lists:flatten([case Scheme of "" -> "";  _ -> [Scheme, "://"] end,
                   Netloc,
                   urlunsplit_path({Path, Query, Fragment})]).
  
  %% @spec urlunsplit_path({Path, Query, Fragment}) -> string()
  %% @doc Assemble a URL path from the 3-tuple.
  urlunsplit_path({Path, Query, Fragment}) ->
    lists:flatten([Path,
                   case Query of "" -> ""; _ -> [$? | Query] end,
                   case Fragment of "" -> ""; _ -> [$# | Fragment] end]).
  
  %% @spec urlsplit_path(Url) -> {Path, Query, Fragment}
  %% @doc Return a 3-tuple, does not expand % escapes. Only supports HTTP style
  %%      paths.
  urlsplit_path(Path) ->
    urlsplit_path(Path, []).
  
  urlsplit_path("", Acc) ->
    {lists:reverse(Acc), "", ""};
  urlsplit_path("?" ++ Rest, Acc) ->
    {Query, Fragment} = urlsplit_query(Rest),
    {lists:reverse(Acc), Query, Fragment};
  urlsplit_path("#" ++ Rest, Acc) ->
    {lists:reverse(Acc), "", Rest};
  urlsplit_path([C | Rest], Acc) ->
    urlsplit_path(Rest, [C | Acc]).
  
  urlsplit_query(Query) ->
    urlsplit_query(Query, []).
  
  urlsplit_query("", Acc) ->
    {lists:reverse(Acc), ""};
  urlsplit_query("#" ++ Rest, Acc) ->
    {lists:reverse(Acc), Rest};
  urlsplit_query([C | Rest], Acc) ->
    urlsplit_query(Rest, [C | Acc]).
  
  %% @spec guess_mime(string()) -> string()
  %% @doc  Guess the mime type of a file by the extension of its filename.
  guess_mime(File) ->
    case filename:extension(File) of
      ".html" ->
        "text/html";
      ".xhtml" ->
        "application/xhtml+xml";
      ".xml" ->
        "application/xml";
      ".css" ->
        "text/css";
      ".js" ->
        "application/x-javascript";
      ".jpg" ->
        "image/jpeg";
      ".gif" ->
        "image/gif";
      ".png" ->
        "image/png";
      ".swf" ->
        "application/x-shockwave-flash";
      ".zip" ->
        "application/zip";
      ".bz2" ->
        "application/x-bzip2";
      ".gz" ->
        "application/x-gzip";
      ".tar" ->
        "application/x-tar";
      ".tgz" ->
        "application/x-gzip";
      ".txt" ->
        "text/plain";
      ".doc" ->
        "application/msword";
      ".pdf" ->
        "application/pdf";
      ".xls" ->
        "application/vnd.ms-excel";
      ".rtf" ->
        "application/rtf";
      ".mov" ->
        "video/quicktime";
      ".mp3" ->
        "audio/mpeg";
      ".z" ->
        "application/x-compress";
      ".wav" ->
        "audio/x-wav";
      ".ico" ->
        "image/x-icon";
      ".bmp" ->
        "image/bmp";
      ".m4a" ->
        "audio/mpeg";
      ".m3u" ->
        "audio/x-mpegurl";
      ".exe" ->
        "application/octet-stream";
      ".csv" ->
        "text/csv";
      _ ->
        "text/plain"
    end.
  
  %% @spec parse_header(string()) -> {Type, [{K, V}]}
  %% @doc  Parse a Content-Type like header, return the main Content-Type
  %%       and a property list of options.
  parse_header(String) ->
  %% TODO: This is exactly as broken as Python's cgi module.
  %%       Should parse properly like mochiweb_cookies.
    [Type | Parts] = [string:strip(S) || S <- string:tokens(String, ";")],
    F = fun (S, Acc) ->
            case lists:splitwith(fun (C) -> C =/= $= end, S) of
              {"", _} ->
  %% Skip anything with no name
                Acc;
              {_, ""} ->
  %% Skip anything with no value
                Acc;
              {Name, [$\= | Value]} ->
                [{string:to_lower(string:strip(Name)),
                  unquote_header(string:strip(Value))} | Acc]
            end
        end,
    {string:to_lower(Type),
     lists:foldr(F, [], Parts)}.
  
  unquote_header("\"" ++ Rest) ->
    unquote_header(Rest, []);
  unquote_header(S) ->
    S.
  
  unquote_header("", Acc) ->
    lists:reverse(Acc);
  unquote_header("\"", Acc) ->
    lists:reverse(Acc);
  unquote_header([$\\, C | Rest], Acc) ->
    unquote_header(Rest, [C | Acc]);
  unquote_header([C | Rest], Acc) ->
    unquote_header(Rest, [C | Acc]).
  
  %% @spec record_to_proplist(Record, Fields) -> proplist()
  %% @doc calls record_to_proplist/3 with a default TypeKey of '__record'
  record_to_proplist(Record, Fields) ->
    record_to_proplist(Record, Fields, '__record').
  
  %% @spec record_to_proplist(Record, Fields, TypeKey) -> proplist()
  %% @doc Return a proplist of the given Record with each field in the
  