diff options
Diffstat (limited to 'lib/stdlib/src/base64.erl')
| -rw-r--r-- | lib/stdlib/src/base64.erl | 623 |
1 files changed, 356 insertions, 267 deletions
diff --git a/lib/stdlib/src/base64.erl b/lib/stdlib/src/base64.erl index 5885745fb1..6ea4147abf 100644 --- a/lib/stdlib/src/base64.erl +++ b/lib/stdlib/src/base64.erl @@ -24,22 +24,11 @@ -export([encode/1, decode/1, mime_decode/1, encode_to_string/1, decode_to_string/1, mime_decode_to_string/1]). -%%------------------------------------------------------------------------- %% The following type is a subtype of string() for return values %% of (some) functions of this module. -%%------------------------------------------------------------------------- - -type ascii_string() :: [1..255]. -type ascii_binary() :: binary(). -%%------------------------------------------------------------------------- -%% encode_to_string(ASCII) -> Base64String -%% ASCII - string() | binary() -%% Base64String - string() -%% -%% Description: Encodes a plain ASCII string (or binary) into base64. -%%------------------------------------------------------------------------- - -spec encode_to_string(Data) -> Base64String when Data :: ascii_string() | ascii_binary(), Base64String :: ascii_string(). @@ -47,107 +36,89 @@ encode_to_string(Bin) when is_binary(Bin) -> encode_to_string(binary_to_list(Bin)); encode_to_string(List) when is_list(List) -> - encode_l(List). - -%%------------------------------------------------------------------------- -%% encode(ASCII) -> Base64 -%% ASCII - string() | binary() -%% Base64 - binary() -%% -%% Description: Encodes a plain ASCII string (or binary) into base64. -%%------------------------------------------------------------------------- + encode_list_to_string(List). -spec encode(Data) -> Base64 when Data :: ascii_string() | ascii_binary(), Base64 :: ascii_binary(). encode(Bin) when is_binary(Bin) -> - encode_binary(Bin); + encode_binary(Bin, <<>>); encode(List) when is_list(List) -> - list_to_binary(encode_l(List)). + encode_list(List, <<>>). --spec encode_l(ascii_string()) -> ascii_string(). - -encode_l([]) -> +encode_list_to_string([]) -> []; -encode_l([A]) -> - [b64e(A bsr 2), - b64e((A band 3) bsl 4), $=, $=]; -encode_l([A,B]) -> - [b64e(A bsr 2), - b64e(((A band 3) bsl 4) bor (B bsr 4)), - b64e((B band 15) bsl 2), $=]; -encode_l([A,B,C|Ls]) -> - BB = (A bsl 16) bor (B bsl 8) bor C, +encode_list_to_string([B1]) -> + [b64e(B1 bsr 2), + b64e((B1 band 3) bsl 4), $=, $=]; +encode_list_to_string([B1,B2]) -> + [b64e(B1 bsr 2), + b64e(((B1 band 3) bsl 4) bor (B2 bsr 4)), + b64e((B2 band 15) bsl 2), $=]; +encode_list_to_string([B1,B2,B3|Ls]) -> + BB = (B1 bsl 16) bor (B2 bsl 8) bor B3, [b64e(BB bsr 18), b64e((BB bsr 12) band 63), b64e((BB bsr 6) band 63), - b64e(BB band 63) | encode_l(Ls)]. - -encode_binary(Bin) -> - Split = 3*(byte_size(Bin) div 3), - <<Main0:Split/binary,Rest/binary>> = Bin, - Main = << <<(b64e(C)):8>> || <<C:6>> <= Main0 >>, - case Rest of - <<A:6,B:6,C:4>> -> - <<Main/binary,(b64e(A)):8,(b64e(B)):8,(b64e(C bsl 2)):8,$=:8>>; - <<A:6,B:2>> -> - <<Main/binary,(b64e(A)):8,(b64e(B bsl 4)):8,$=:8,$=:8>>; - <<>> -> - Main - end. + b64e(BB band 63) | encode_list_to_string(Ls)]. -%%------------------------------------------------------------------------- -%% mime_decode(Base64) -> ASCII -%% decode(Base64) -> ASCII -%% Base64 - string() | binary() -%% ASCII - binary() -%% -%% Description: Decodes an base64 encoded string to plain ASCII. -%% mime_decode strips away all characters not Base64 before converting, -%% whereas decode crashes if an illegal character is found -%%------------------------------------------------------------------------- +encode_binary(<<>>, A) -> + A; +encode_binary(<<B1:8>>, A) -> + <<A/bits,(b64e(B1 bsr 2)):8,(b64e((B1 band 3) bsl 4)):8,$=:8,$=:8>>; +encode_binary(<<B1:8, B2:8>>, A) -> + <<A/bits,(b64e(B1 bsr 2)):8, + (b64e(((B1 band 3) bsl 4) bor (B2 bsr 4))):8, + (b64e((B2 band 15) bsl 2)):8, $=:8>>; +encode_binary(<<B1:8, B2:8, B3:8, Ls/bits>>, A) -> + BB = (B1 bsl 16) bor (B2 bsl 8) bor B3, + encode_binary(Ls, + <<A/bits,(b64e(BB bsr 18)):8, + (b64e((BB bsr 12) band 63)):8, + (b64e((BB bsr 6) band 63)):8, + (b64e(BB band 63)):8>>). + +encode_list([], A) -> + A; +encode_list([B1], A) -> + <<A/bits,(b64e(B1 bsr 2)):8,(b64e((B1 band 3) bsl 4)):8,$=:8,$=:8>>; +encode_list([B1,B2], A) -> + <<A/bits,(b64e(B1 bsr 2)):8, + (b64e(((B1 band 3) bsl 4) bor (B2 bsr 4))):8, + (b64e((B2 band 15) bsl 2)):8, $=:8>>; +encode_list([B1,B2,B3|Ls], A) -> + BB = (B1 bsl 16) bor (B2 bsl 8) bor B3, + encode_list(Ls, + <<A/bits,(b64e(BB bsr 18)):8, + (b64e((BB bsr 12) band 63)):8, + (b64e((BB bsr 6) band 63)):8, + (b64e(BB band 63)):8>>). + +%% mime_decode strips away all characters not Base64 before +%% converting, whereas decode crashes if an illegal character is found -spec decode(Base64) -> Data when Base64 :: ascii_string() | ascii_binary(), Data :: ascii_binary(). decode(Bin) when is_binary(Bin) -> - decode_binary(<<>>, Bin); + decode_binary(Bin, <<>>); decode(List) when is_list(List) -> - list_to_binary(decode_l(List)). + decode_list(List, <<>>). -spec mime_decode(Base64) -> Data when Base64 :: ascii_string() | ascii_binary(), Data :: ascii_binary(). mime_decode(Bin) when is_binary(Bin) -> - mime_decode_binary(<<>>, Bin); + mime_decode_binary(Bin, <<>>); mime_decode(List) when is_list(List) -> - mime_decode(list_to_binary(List)). - --spec decode_l(ascii_string()) -> ascii_string(). - -decode_l(List) -> - L = strip_spaces(List, []), - decode(L, []). - --spec mime_decode_l(ascii_string()) -> ascii_string(). + mime_decode_list(List, <<>>). -mime_decode_l(List) -> - L = strip_illegal(List, [], 0), - decode(L, []). - -%%------------------------------------------------------------------------- -%% mime_decode_to_string(Base64) -> ASCII -%% decode_to_string(Base64) -> ASCII -%% Base64 - string() | binary() -%% ASCII - binary() -%% -%% Description: Decodes an base64 encoded string to plain ASCII. -%% mime_decode strips away all characters not Base64 before converting, -%% whereas decode crashes if an illegal character is found -%%------------------------------------------------------------------------- +%% mime_decode_to_string strips away all characters not Base64 before +%% converting, whereas decode_to_string crashes if an illegal +%% character is found -spec decode_to_string(Base64) -> DataString when Base64 :: ascii_string() | ascii_binary(), @@ -156,7 +127,7 @@ mime_decode_l(List) -> decode_to_string(Bin) when is_binary(Bin) -> decode_to_string(binary_to_list(Bin)); decode_to_string(List) when is_list(List) -> - decode_l(List). + decode_list_to_string(List). -spec mime_decode_to_string(Base64) -> DataString when Base64 :: ascii_string() | ascii_binary(), @@ -165,202 +136,326 @@ decode_to_string(List) when is_list(List) -> mime_decode_to_string(Bin) when is_binary(Bin) -> mime_decode_to_string(binary_to_list(Bin)); mime_decode_to_string(List) when is_list(List) -> - mime_decode_l(List). - -%% 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,62,bad,bad,bad,63, %32-47 - 52,53,54,55,56,57,58,59,60,61,bad,bad,bad,eq,bad,bad, %48-63 - bad,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14, - 15,16,17,18,19,20,21,22,23,24,25,bad,bad,bad,bad,bad, - bad,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, - 41,42,43,44,45,46,47,48,49,50,51,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,bad,bad,bad,bad,bad}). - -decode_binary(Result0, <<C:8,T0/bits>>) -> - case element(C, ?DECODE_MAP) of - bad -> - erlang:error({badarg,C}); - ws -> - decode_binary(Result0, T0); - eq -> - case strip_ws(T0) of - <<$=:8,T/binary>> -> - <<>> = strip_ws(T), - Split = byte_size(Result0) - 1, - <<Result:Split/bytes,_:4>> = Result0, - Result; - T -> - <<>> = strip_ws(T), - Split = byte_size(Result0) - 1, - <<Result:Split/bytes,_:2>> = Result0, - Result - end; - Bits -> - decode_binary(<<Result0/bits,Bits:6>>, T0) - end; -decode_binary(Result, <<>>) -> - true = is_binary(Result), - Result. + mime_decode_list_to_string(List). %% Skipping pad character if not at end of string. Also liberal about %% excess padding and skipping of other illegal (non-base64 alphabet) %% characters. See section 3.3 of RFC4648 -mime_decode_binary(Result, <<0:8,T/bits>>) -> - mime_decode_binary(Result, T); -mime_decode_binary(Result0, <<C:8,T/bits>>) -> - case element(C, ?DECODE_MAP) of - Bits when is_integer(Bits) -> - mime_decode_binary(<<Result0/bits,Bits:6>>, T); +mime_decode_list([0 | Cs], A) -> + mime_decode_list(Cs, A); +mime_decode_list([C1 | Cs], A) -> + case b64d(C1) of + B1 when is_integer(B1) -> mime_decode_list(Cs, A, B1); + _ -> mime_decode_list(Cs, A) % eq is padding + end; +mime_decode_list([], A) -> + A. + +mime_decode_list([0 | Cs], A, B1) -> + mime_decode_list(Cs, A, B1); +mime_decode_list([C2 | Cs], A, B1) -> + case b64d(C2) of + B2 when is_integer(B2) -> + mime_decode_list(Cs, A, B1, B2); + _ -> mime_decode_list(Cs, A, B1) % eq is padding + end. + +mime_decode_list([0 | Cs], A, B1, B2) -> + mime_decode_list(Cs, A, B1, B2); +mime_decode_list([C3 | Cs], A, B1, B2) -> + case b64d(C3) of + B3 when is_integer(B3) -> + mime_decode_list(Cs, A, B1, B2, B3); + eq=B3 -> + mime_decode_list_after_eq(Cs, A, B1, B2, B3); + _ -> mime_decode_list(Cs, A, B1, B2) + end. + +mime_decode_list([0 | Cs], A, B1, B2, B3) -> + mime_decode_list(Cs, A, B1, B2, B3); +mime_decode_list([C4 | Cs], A, B1, B2, B3) -> + case b64d(C4) of + B4 when is_integer(B4) -> + mime_decode_list(Cs, <<A/bits,B1:6,B2:6,B3:6,B4:6>>); eq -> - mime_decode_binary_after_eq(Result0, T, false); - _ -> - mime_decode_binary(Result0, T) + mime_decode_list_after_eq(Cs, A, B1, B2, B3); + _ -> mime_decode_list(Cs, A, B1, B2, B3) + end. + +mime_decode_list_after_eq([0 | Cs], A, B1, B2, B3) -> + mime_decode_list_after_eq(Cs, A, B1, B2, B3); +mime_decode_list_after_eq([C | Cs], A, B1, B2, B3) -> + case b64d(C) of + B when is_integer(B) -> + %% More valid data, skip the eq as invalid + case B3 of + eq -> mime_decode_list(Cs, A, B1, B2, B); + _ -> mime_decode_list(Cs, <<A/bits,B1:6,B2:6,B3:6,B:6>>) + end; + _ -> mime_decode_list_after_eq(Cs, A, B1, B2, B3) end; -mime_decode_binary(Result, _) -> - true = is_binary(Result), - Result. - -mime_decode_binary_after_eq(Result, <<0:8,T/bits>>, Eq) -> - mime_decode_binary_after_eq(Result, T, Eq); -mime_decode_binary_after_eq(Result0, <<C:8,T/bits>>, Eq) -> - case element(C, ?DECODE_MAP) of - bad -> - mime_decode_binary_after_eq(Result0, T, Eq); - ws -> - mime_decode_binary_after_eq(Result0, T, Eq); +mime_decode_list_after_eq([], A, B1, B2, eq) -> + <<A/bits,B1:6,(B2 bsr 4):2>>; +mime_decode_list_after_eq([], A, B1, B2, B3) -> + <<A/bits,B1:6,B2:6,(B3 bsr 2):4>>. + +mime_decode_binary(<<0:8, Cs/bits>>, A) -> + mime_decode_binary(Cs, A); +mime_decode_binary(<<C1:8, Cs/bits>>, A) -> + case b64d(C1) of + B1 when is_integer(B1) -> mime_decode_binary(Cs, A, B1); + _ -> mime_decode_binary(Cs, A) % eq is padding + end; +mime_decode_binary(<<>>, A) -> + A. + +mime_decode_binary(<<0:8, Cs/bits>>, A, B1) -> + mime_decode_binary(Cs, A, B1); +mime_decode_binary(<<C2:8, Cs/bits>>, A, B1) -> + case b64d(C2) of + B2 when is_integer(B2) -> + mime_decode_binary(Cs, A, B1, B2); + _ -> mime_decode_binary(Cs, A, B1) % eq is padding + end. + +mime_decode_binary(<<0:8, Cs/bits>>, A, B1, B2) -> + mime_decode_binary(Cs, A, B1, B2); +mime_decode_binary(<<C3:8, Cs/bits>>, A, B1, B2) -> + case b64d(C3) of + B3 when is_integer(B3) -> + mime_decode_binary(Cs, A, B1, B2, B3); + eq=B3 -> + mime_decode_binary_after_eq(Cs, A, B1, B2, B3); + _ -> mime_decode_binary(Cs, A, B1, B2) + end. + +mime_decode_binary(<<0:8, Cs/bits>>, A, B1, B2, B3) -> + mime_decode_binary(Cs, A, B1, B2, B3); +mime_decode_binary(<<C4:8, Cs/bits>>, A, B1, B2, B3) -> + case b64d(C4) of + B4 when is_integer(B4) -> + mime_decode_binary(Cs, <<A/bits,B1:6,B2:6,B3:6,B4:6>>); eq -> - mime_decode_binary_after_eq(Result0, T, true); - Bits when is_integer(Bits) -> + mime_decode_binary_after_eq(Cs, A, B1, B2, B3); + _ -> mime_decode_binary(Cs, A, B1, B2, B3) + end. + +mime_decode_binary_after_eq(<<0:8, Cs/bits>>, A, B1, B2, B3) -> + mime_decode_binary_after_eq(Cs, A, B1, B2, B3); +mime_decode_binary_after_eq(<<C:8, Cs/bits>>, A, B1, B2, B3) -> + case b64d(C) of + B when is_integer(B) -> %% More valid data, skip the eq as invalid - mime_decode_binary(<<Result0/bits,Bits:6>>, T) + case B3 of + eq -> mime_decode_binary(Cs, A, B1, B2, B); + _ -> mime_decode_binary(Cs, <<A/bits,B1:6,B2:6,B3:6,B:6>>) + end; + _ -> mime_decode_binary_after_eq(Cs, A, B1, B2, B3) + end; +mime_decode_binary_after_eq(<<>>, A, B1, B2, eq) -> + <<A/bits,B1:6,(B2 bsr 4):2>>; +mime_decode_binary_after_eq(<<>>, A, B1, B2, B3) -> + <<A/bits,B1:6,B2:6,(B3 bsr 2):4>>. + +mime_decode_list_to_string([0 | Cs]) -> + mime_decode_list_to_string(Cs); +mime_decode_list_to_string([C1 | Cs]) -> + case b64d(C1) of + B1 when is_integer(B1) -> mime_decode_list_to_string(Cs, B1); + _ -> mime_decode_list_to_string(Cs) % eq is padding end; -mime_decode_binary_after_eq(Result0, <<>>, Eq) -> - %% No more valid data. - case bit_size(Result0) rem 8 of - 0 -> - %% '====' is not uncommon. - Result0; - 4 when Eq -> - %% enforce at least one more '=' only ignoring illegals and spacing - Split = byte_size(Result0) - 1, - <<Result:Split/bytes,_:4>> = Result0, - Result; - 2 -> - %% remove 2 bits - Split = byte_size(Result0) - 1, - <<Result:Split/bytes,_:2>> = Result0, - Result +mime_decode_list_to_string([]) -> + []. + +mime_decode_list_to_string([0 | Cs], B1) -> + mime_decode_list_to_string(Cs, B1); +mime_decode_list_to_string([C2 | Cs], B1) -> + case b64d(C2) of + B2 when is_integer(B2) -> + mime_decode_list_to_string(Cs, B1, B2); + _ -> mime_decode_list_to_string(Cs, B1) % eq is padding end. -decode([], A) -> A; -decode([$=,$=,C2,C1|Cs], A) -> - Bits2x6 = (b64d(C1) bsl 18) bor (b64d(C2) bsl 12), - Octet1 = Bits2x6 bsr 16, - decode(Cs, [Octet1|A]); -decode([$=,C3,C2,C1|Cs], A) -> - Bits3x6 = (b64d(C1) bsl 18) bor (b64d(C2) bsl 12) - bor (b64d(C3) bsl 6), - Octet1 = Bits3x6 bsr 16, - Octet2 = (Bits3x6 bsr 8) band 16#ff, - decode(Cs, [Octet1,Octet2|A]); -decode([C4,C3,C2,C1| Cs], A) -> - Bits4x6 = (b64d(C1) bsl 18) bor (b64d(C2) bsl 12) - bor (b64d(C3) bsl 6) bor b64d(C4), - Octet1 = Bits4x6 bsr 16, - Octet2 = (Bits4x6 bsr 8) band 16#ff, - Octet3 = Bits4x6 band 16#ff, - decode(Cs, [Octet1,Octet2,Octet3|A]). +mime_decode_list_to_string([0 | Cs], B1, B2) -> + mime_decode_list_to_string(Cs, B1, B2); +mime_decode_list_to_string([C3 | Cs], B1, B2) -> + case b64d(C3) of + B3 when is_integer(B3) -> + mime_decode_list_to_string(Cs, B1, B2, B3); + eq=B3 -> mime_decode_list_to_string_after_eq(Cs, B1, B2, B3); + _ -> mime_decode_list_to_string(Cs, B1, B2) + end. -%%%======================================================================== -%%% Internal functions -%%%======================================================================== +mime_decode_list_to_string([0 | Cs], B1, B2, B3) -> + mime_decode_list_to_string(Cs, B1, B2, B3); +mime_decode_list_to_string([C4 | Cs], B1, B2, B3) -> + case b64d(C4) of + B4 when is_integer(B4) -> + Bits4x6 = (B1 bsl 18) bor (B2 bsl 12) bor (B3 bsl 6) bor B4, + Octet1 = Bits4x6 bsr 16, + Octet2 = (Bits4x6 bsr 8) band 16#ff, + Octet3 = Bits4x6 band 16#ff, + [Octet1, Octet2, Octet3 | mime_decode_list_to_string(Cs)]; + eq -> + mime_decode_list_to_string_after_eq(Cs, B1, B2, B3); + _ -> mime_decode_list_to_string(Cs, B1, B2, B3) + end. -strip_spaces([], A) -> A; -strip_spaces([$\s|Cs], A) -> strip_spaces(Cs, A); -strip_spaces([$\t|Cs], A) -> strip_spaces(Cs, A); -strip_spaces([$\r|Cs], A) -> strip_spaces(Cs, A); -strip_spaces([$\n|Cs], A) -> strip_spaces(Cs, A); -strip_spaces([C|Cs], A) -> strip_spaces(Cs, [C | A]). - -strip_ws(<<$\t,T/binary>>) -> - strip_ws(T); -strip_ws(<<$\n,T/binary>>) -> - strip_ws(T); -strip_ws(<<$\r,T/binary>>) -> - strip_ws(T); -strip_ws(<<$\s,T/binary>>) -> - strip_ws(T); -strip_ws(T) -> T. +mime_decode_list_to_string_after_eq([0 | Cs], B1, B2, B3) -> + mime_decode_list_to_string_after_eq(Cs, B1, B2, B3); +mime_decode_list_to_string_after_eq([C | Cs], B1, B2, B3) -> + case b64d(C) of + B when is_integer(B) -> + %% More valid data, skip the eq as invalid + case B3 of + eq -> mime_decode_list_to_string(Cs, B1, B2, B); + _ -> + Bits4x6 = (B1 bsl 18) bor (B2 bsl 12) bor (B3 bsl 6) bor B, + Octet1 = Bits4x6 bsr 16, + Octet2 = (Bits4x6 bsr 8) band 16#ff, + Octet3 = Bits4x6 band 16#ff, + [Octet1, Octet2, Octet3 | mime_decode_list_to_string(Cs)] + end; + _ -> mime_decode_list_to_string_after_eq(Cs, B1, B2, B3) + end; +mime_decode_list_to_string_after_eq([], B1, B2, eq) -> + binary_to_list(<<B1:6,(B2 bsr 4):2>>); +mime_decode_list_to_string_after_eq([], B1, B2, B3) -> + binary_to_list(<<B1:6,B2:6,(B3 bsr 2):4>>). + +decode_list([C1 | Cs], A) -> + case b64d(C1) of + ws -> decode_list(Cs, A); + B1 -> decode_list(Cs, A, B1) + end; +decode_list([], A) -> + A. -%% Skipping pad character if not at end of string. Also liberal about -%% excess padding and skipping of other illegal (non-base64 alphabet) -%% characters. See section 3.3 of RFC4648 -strip_illegal([], A, _Cnt) -> +decode_list([C2 | Cs], A, B1) -> + case b64d(C2) of + ws -> decode_list(Cs, A, B1); + B2 -> decode_list(Cs, A, B1, B2) + end. + +decode_list([C3 | Cs], A, B1, B2) -> + case b64d(C3) of + ws -> decode_list(Cs, A, B1, B2); + B3 -> decode_list(Cs, A, B1, B2, B3) + end. + +decode_list([C4 | Cs], A, B1, B2, B3) -> + case b64d(C4) of + ws -> decode_list(Cs, A, B1, B2, B3); + eq when B3 =:= eq -> only_ws(Cs, <<A/bits,B1:6,(B2 bsr 4):2>>); + eq -> only_ws(Cs, <<A/bits,B1:6,B2:6,(B3 bsr 2):4>>); + B4 -> decode_list(Cs, <<A/bits,B1:6,B2:6,B3:6,B4:6>>) + end. + +decode_binary(<<C1:8, Cs/bits>>, A) -> + case b64d(C1) of + ws -> decode_binary(Cs, A); + B1 -> decode_binary(Cs, A, B1) + end; +decode_binary(<<>>, A) -> + A. + +decode_binary(<<C2:8, Cs/bits>>, A, B1) -> + case b64d(C2) of + ws -> decode_binary(Cs, A, B1); + B2 -> decode_binary(Cs, A, B1, B2) + end. + +decode_binary(<<C3:8, Cs/bits>>, A, B1, B2) -> + case b64d(C3) of + ws -> decode_binary(Cs, A, B1, B2); + B3 -> decode_binary(Cs, A, B1, B2, B3) + end. + +decode_binary(<<C4:8, Cs/bits>>, A, B1, B2, B3) -> + case b64d(C4) of + ws -> decode_binary(Cs, A, B1, B2, B3); + eq when B3 =:= eq -> only_ws_binary(Cs, <<A/bits,B1:6,(B2 bsr 4):2>>); + eq -> only_ws_binary(Cs, <<A/bits,B1:6,B2:6,(B3 bsr 2):4>>); + B4 -> decode_binary(Cs, <<A/bits,B1:6,B2:6,B3:6,B4:6>>) + end. + +only_ws_binary(<<>>, A) -> A; -strip_illegal([0|Cs], A, Cnt) -> - strip_illegal(Cs, A, Cnt); -strip_illegal([C|Cs], A, Cnt) -> - case element(C, ?DECODE_MAP) of - bad -> - strip_illegal(Cs, A, Cnt); - ws -> - strip_illegal(Cs, A, Cnt); - eq -> - case {tail_contains_more(Cs, false), Cnt rem 4} of - {{[], _}, 0} -> - A; %% Ignore extra = - {{[], true}, 2} -> - [$=|[$=|A]]; %% 'XX==' - {{[], _}, 3} -> - [$=|A]; %% 'XXX=' - {{[H|T], _}, _} -> - %% more data, skip equals - strip_illegal(T, [H|A], Cnt+1) - end; - _ -> - strip_illegal(Cs, [C|A], Cnt+1) +only_ws_binary(<<C:8, Cs/bits>>, A) -> + case b64d(C) of + ws -> only_ws_binary(Cs, A) end. -%% Search the tail for more valid data and remember if we saw -%% another equals along the way. -tail_contains_more([], Eq) -> - {[], Eq}; -tail_contains_more(<<>>, Eq) -> - {<<>>, Eq}; -tail_contains_more([C|T]=More, Eq) -> - case element(C, ?DECODE_MAP) of - bad -> - tail_contains_more(T, Eq); - ws -> - tail_contains_more(T, Eq); - eq -> - tail_contains_more(T, true); - _ -> - {More, Eq} +decode_list_to_string([C1 | Cs]) -> + case b64d(C1) of + ws -> decode_list_to_string(Cs); + B1 -> decode_list_to_string(Cs, B1) end; -tail_contains_more(<<C:8,T/bits>> =More, Eq) -> - case element(C, ?DECODE_MAP) of - bad -> - tail_contains_more(T, Eq); - ws -> - tail_contains_more(T, Eq); - eq -> - tail_contains_more(T, true); - _ -> - {More, Eq} +decode_list_to_string([]) -> + []. + +decode_list_to_string([C2 | Cs], B1) -> + case b64d(C2) of + ws -> decode_list_to_string(Cs, B1); + B2 -> decode_list_to_string(Cs, B1, B2) end. - + +decode_list_to_string([C3 | Cs], B1, B2) -> + case b64d(C3) of + ws -> decode_list_to_string(Cs, B1, B2); + B3 -> decode_list_to_string(Cs, B1, B2, B3) + end. + +decode_list_to_string([C4 | Cs], B1, B2, B3) -> + case b64d(C4) of + ws -> + decode_list_to_string(Cs, B1, B2, B3); + eq when B3 =:= eq -> + only_ws(Cs, binary_to_list(<<B1:6,(B2 bsr 4):2>>)); + eq -> + only_ws(Cs, binary_to_list(<<B1:6,B2:6,(B3 bsr 2):4>>)); + B4 -> + Bits4x6 = (B1 bsl 18) bor (B2 bsl 12) bor (B3 bsl 6) bor B4, + Octet1 = Bits4x6 bsr 16, + Octet2 = (Bits4x6 bsr 8) band 16#ff, + Octet3 = Bits4x6 band 16#ff, + [Octet1, Octet2, Octet3 | decode_list_to_string(Cs)] + end. + +only_ws([], A) -> + A; +only_ws([C | Cs], A) -> + case b64d(C) of + ws -> only_ws(Cs, A) + end. + +%%%======================================================================== +%%% Internal functions +%%%======================================================================== + %% accessors +-compile({inline, [{b64d, 1}]}). +%% One-based decode map. +b64d(X) -> + element(X, + {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,62,bad,bad,bad,63, %32-47 + 52,53,54,55,56,57,58,59,60,61,bad,bad,bad,eq,bad,bad, %48-63 + bad,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14, + 15,16,17,18,19,20,21,22,23,24,25,bad,bad,bad,bad,bad, + bad,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, + 41,42,43,44,45,46,47,48,49,50,51,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,bad,bad,bad,bad,bad}). + +-compile({inline, [{b64e, 1}]}). b64e(X) -> element(X+1, {$A, $B, $C, $D, $E, $F, $G, $H, $I, $J, $K, $L, $M, $N, @@ -368,9 +463,3 @@ b64e(X) -> $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. |