| %% @author Bob Ippolito <bob@mochimedia.com> |
| %% @copyright 2013 Mochi Media, Inc. |
| %% |
| %% Permission is hereby granted, free of charge, to any person obtaining a |
| %% copy of this software and associated documentation files (the "Software"), |
| %% to deal in the Software without restriction, including without limitation |
| %% the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| %% and/or sell copies of the Software, and to permit persons to whom the |
| %% Software is furnished to do so, subject to the following conditions: |
| %% |
| %% The above copyright notice and this permission notice shall be included in |
| %% all copies or substantial portions of the Software. |
| %% |
| %% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| %% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| %% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| %% THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| %% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| %% FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| %% DEALINGS IN THE SOFTWARE. |
| |
| -module(mochiweb_base64url). |
| -export([encode/1, decode/1]). |
| |
| %% @doc URL and filename safe base64 variant with no padding, |
| %% also known as "base64url" per RFC 4648. |
| %% |
| %% This differs from base64 in the following ways: |
| %% '-' is used in place of '+' (62), |
| %% '_' is used in place of '/' (63), |
| %% padding is implicit rather than explicit ('='). |
| |
| -spec encode(iolist() | binary()) -> binary(). |
| encode(B) when is_binary(B) -> |
| encode_binary(B); |
| encode(L) when is_list(L) -> |
| encode_binary(iolist_to_binary(L)). |
| |
| -spec decode(iolist() | binary()) -> binary(). |
| decode(B) when is_binary(B) -> |
| decode_binary(B); |
| decode(L) when is_list(L) -> |
| decode_binary(iolist_to_binary(L)). |
| |
| %% Implementation, derived from stdlib base64.erl |
| |
| %% One-based decode map. |
| -define(DECODE_MAP, |
| {bad,bad,bad,bad,bad,bad,bad,bad,ws,ws,bad,bad,ws,bad,bad, %1-15 |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, %16-31 |
| ws,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,62,bad,bad, %32-47 |
| 52,53,54,55,56,57,58,59,60,61,bad,bad,bad,bad,bad,bad, %48-63 |
| bad,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14, %64-79 |
| 15,16,17,18,19,20,21,22,23,24,25,bad,bad,bad,bad,63, %80-95 |
| bad,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, %96-111 |
| 41,42,43,44,45,46,47,48,49,50,51,bad,bad,bad,bad,bad, %112-127 |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad, |
| bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad,bad}). |
| |
| encode_binary(Bin) -> |
| Split = 3*(byte_size(Bin) div 3), |
| <<Main0:Split/binary,Rest/binary>> = Bin, |
| Main = << <<(b64e(C)):8>> || <<C:6>> <= Main0 >>, |
| case Rest of |
| <<A:6,B:6,C:4>> -> |
| <<Main/binary,(b64e(A)):8,(b64e(B)):8,(b64e(C bsl 2)):8>>; |
| <<A:6,B:2>> -> |
| <<Main/binary,(b64e(A)):8,(b64e(B bsl 4)):8>>; |
| <<>> -> |
| Main |
| end. |
| |
| decode_binary(Bin) -> |
| Main = << <<(b64d(C)):6>> || <<C>> <= Bin, |
| (C =/= $\t andalso C =/= $\s andalso |
| C =/= $\r andalso C =/= $\n) >>, |
| case bit_size(Main) rem 8 of |
| 0 -> |
| Main; |
| N -> |
| Split = byte_size(Main) - 1, |
| <<Result:Split/bytes, _:N>> = Main, |
| Result |
| end. |
| |
| %% accessors |
| |
| b64e(X) -> |
| element(X+1, |
| {$A, $B, $C, $D, $E, $F, $G, $H, $I, $J, $K, $L, $M, $N, |
| $O, $P, $Q, $R, $S, $T, $U, $V, $W, $X, $Y, $Z, |
| $a, $b, $c, $d, $e, $f, $g, $h, $i, $j, $k, $l, $m, $n, |
| $o, $p, $q, $r, $s, $t, $u, $v, $w, $x, $y, $z, |
| $0, $1, $2, $3, $4, $5, $6, $7, $8, $9, $-, $_}). |
| |
| b64d(X) -> |
| b64d_ok(element(X, ?DECODE_MAP)). |
| |
| b64d_ok(I) when is_integer(I) -> I. |