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base32_clockwork

2021.2.0
2023.1.0 2021.3.0 2021.2.0

Clockwork Base32

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base32_clockwork src base32_crockford.erl
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src/base32_crockford.erl 

-module(base32_crockford).



-export([encode/1, encode_check/1, decode/1, decode_check/1]).



-import(base32_utils, [rev_bits_list_to_binary/1]).



data_to_integer(Data, Padding) ->

    data_to_integer0(Data, Padding, 0).



data_to_integer0(<<>>, _, N) ->

    N;

data_to_integer0(<<Bits:1>>, true, N) ->

    (N bsl 5) bor (Bits bsl 4);

data_to_integer0(<<Bits:2>>, true, N) ->

    (N bsl 5) bor (Bits bsl 3);

data_to_integer0(<<Bits:3>>, true, N) ->

    (N bsl 5) bor (Bits bsl 2);

data_to_integer0(<<Bits:4>>, true, N) ->

    (N bsl 5) bor (Bits bsl 1);

data_to_integer0(<<Bits:1>>, false, N) ->

    (N bsl 1) bor Bits;

data_to_integer0(<<Bits:2>>, false, N) ->

    (N bsl 2) bor Bits;

data_to_integer0(<<Bits:3>>, false, N) ->

    (N bsl 3) bor Bits;

data_to_integer0(<<Bits:4>>, false, N) ->

    (N bsl 4) bor Bits;

data_to_integer0(<<Bits:5, Next/bitstring>>, Padding, N) ->

    data_to_integer0(Next, Padding, (N bsl 5) bor Bits).



-spec encode(binary() | integer()) -> binary().

encode(Value) ->

    Encoded = encode0(Value, []),

    list_to_binary(Encoded).



-spec encode_check(binary()) -> binary().

encode_check(Data) when is_binary(Data) ->

    Check = check_symbol(data_to_integer(Data, false)),

    Encoded = encode0(Data, [Check]),

    list_to_binary(Encoded);

encode_check(Value) ->

    Check = check_symbol(Value),

    Encoded = encode0(Value, [Check]),

    list_to_binary(Encoded).



encode0(Data, Accu) when is_binary(Data) ->

    Size = size(Data) * 8,

    BaseCount = Size div 5,

    Count = case Size rem 5 of

                0 -> BaseCount;

                _ -> BaseCount + 1

            end,

    encode1(data_to_integer(Data, true), Count, Accu);

encode0(Value, Accu) ->

    BaseCount = Value div 32,

    Count = case Value rem 32 of

                0 -> BaseCount;

                _ -> BaseCount + 1

            end,

    encode1(Value, Count, Accu).



encode1(_, 0, Accu) ->

    Accu;

encode1(Value, Count, Accu) ->

    Next = Value div 32,

    SymVal = Value rem 32,

    encode1(Next, Count - 1, [symbol(SymVal)|Accu]).



check_symbol(Value) ->

    symbol(Value rem 37).



symbol(0) -> $0;

symbol(1) -> $1;

symbol(2) -> $2;

symbol(3) -> $3;

symbol(4) -> $4;

symbol(5) -> $5;

symbol(6) -> $6;

symbol(7) -> $7;

symbol(8) -> $8;

symbol(9) -> $9;

symbol(10) -> $A;

symbol(11) -> $B;

symbol(12) -> $C;

symbol(13) -> $D;

symbol(14) -> $E;

symbol(15) -> $F;

symbol(16) -> $G;

symbol(17) -> $H;

symbol(18) -> $J;

symbol(19) -> $K;

symbol(20) -> $M;

symbol(21) -> $N;

symbol(22) -> $P;

symbol(23) -> $Q;

symbol(24) -> $R;

symbol(25) -> $S;

symbol(26) -> $T;

symbol(27) -> $V;

symbol(28) -> $W;

symbol(29) -> $X;

symbol(30) -> $Y;

symbol(31) -> $Z;

symbol(32) -> $*;

symbol(33) -> $~;

symbol(34) -> $$;

symbol(35) -> $=;

symbol(36) -> $U.



-spec decode(binary()) -> binary().

decode(Data) when is_binary(Data) ->

    decode0(Data, []).



-spec decode_check(binary()) -> {ok, binary()} | {error, atom()}.

decode_check(Data) ->

    Size = (size(Data) - 1) * 8,

    <<Data0:Size/bitstring, Expectedcheck:8>> = Data,

    Decoded = decode(Data0),

    Check = check_symbol(data_to_integer(Decoded, false)),

    case Check =:= Expectedcheck of

        true -> {ok, Decoded};

        false -> {error, invalid}

    end.



decode0(<<>>, Accu) ->

    Decoded0 = rev_bits_list_to_binary(Accu),

    DecodedSize = bit_size(Decoded0),

    case DecodedSize rem 8 of

        0 ->

            Decoded0;

        PaddingSize ->

            DataSize = DecodedSize - PaddingSize,

            <<Decoded1:DataSize/bitstring, 0:PaddingSize>> = Decoded0,

            Decoded1

    end;

decode0(<<"0", Next/bitstring>>, Accu) ->

    decode0(Next, [<<0:5>>|Accu]);

decode0(<<"O", Next/bitstring>>, Accu) ->

    decode0(Next, [<<0:5>>|Accu]);

decode0(<<"o", Next/bitstring>>, Accu) ->

    decode0(Next, [<<0:5>>|Accu]);

decode0(<<"1", Next/bitstring>>, Accu) ->

    decode0(Next, [<<1:5>>|Accu]);

decode0(<<"I", Next/bitstring>>, Accu) ->

    decode0(Next, [<<1:5>>|Accu]);

decode0(<<"i", Next/bitstring>>, Accu) ->

    decode0(Next, [<<1:5>>|Accu]);

decode0(<<"L", Next/bitstring>>, Accu) ->

    decode0(Next, [<<1:5>>|Accu]);

decode0(<<"l", Next/bitstring>>, Accu) ->

    decode0(Next, [<<1:5>>|Accu]);

decode0(<<"2", Next/bitstring>>, Accu) ->

    decode0(Next, [<<2:5>>|Accu]);

decode0(<<"3", Next/bitstring>>, Accu) ->

    decode0(Next, [<<3:5>>|Accu]);

decode0(<<"4", Next/bitstring>>, Accu) ->

    decode0(Next, [<<4:5>>|Accu]);

decode0(<<"5", Next/bitstring>>, Accu) ->

    decode0(Next, [<<5:5>>|Accu]);

decode0(<<"6", Next/bitstring>>, Accu) ->

    decode0(Next, [<<6:5>>|Accu]);

decode0(<<"7", Next/bitstring>>, Accu) ->

    decode0(Next, [<<7:5>>|Accu]);

decode0(<<"8", Next/bitstring>>, Accu) ->

    decode0(Next, [<<8:5>>|Accu]);

decode0(<<"9", Next/bitstring>>, Accu) ->

    decode0(Next, [<<9:5>>|Accu]);

decode0(<<"A", Next/bitstring>>, Accu) ->

    decode0(Next, [<<10:5>>|Accu]);

decode0(<<"a", Next/bitstring>>, Accu) ->

    decode0(Next, [<<10:5>>|Accu]);

decode0(<<"B", Next/bitstring>>, Accu) ->

    decode0(Next, [<<11:5>>|Accu]);

decode0(<<"b", Next/bitstring>>, Accu) ->

    decode0(Next, [<<11:5>>|Accu]);

decode0(<<"C", Next/bitstring>>, Accu) ->

    decode0(Next, [<<12:5>>|Accu]);

decode0(<<"c", Next/bitstring>>, Accu) ->

    decode0(Next, [<<12:5>>|Accu]);

decode0(<<"D", Next/bitstring>>, Accu) ->

    decode0(Next, [<<13:5>>|Accu]);

decode0(<<"d", Next/bitstring>>, Accu) ->

    decode0(Next, [<<13:5>>|Accu]);

decode0(<<"E", Next/bitstring>>, Accu) ->

    decode0(Next, [<<14:5>>|Accu]);

decode0(<<"e", Next/bitstring>>, Accu) ->

    decode0(Next, [<<14:5>>|Accu]);

decode0(<<"F", Next/bitstring>>, Accu) ->

    decode0(Next, [<<15:5>>|Accu]);

decode0(<<"f", Next/bitstring>>, Accu) ->

    decode0(Next, [<<15:5>>|Accu]);

decode0(<<"G", Next/bitstring>>, Accu) ->

    decode0(Next, [<<16:5>>|Accu]);

decode0(<<"g", Next/bitstring>>, Accu) ->

    decode0(Next, [<<16:5>>|Accu]);

decode0(<<"H", Next/bitstring>>, Accu) ->

    decode0(Next, [<<17:5>>|Accu]);

decode0(<<"h", Next/bitstring>>, Accu) ->

    decode0(Next, [<<17:5>>|Accu]);

decode0(<<"J", Next/bitstring>>, Accu) ->

    decode0(Next, [<<18:5>>|Accu]);

decode0(<<"j", Next/bitstring>>, Accu) ->

    decode0(Next, [<<18:5>>|Accu]);

decode0(<<"K", Next/bitstring>>, Accu) ->

    decode0(Next, [<<19:5>>|Accu]);

decode0(<<"k", Next/bitstring>>, Accu) ->

    decode0(Next, [<<19:5>>|Accu]);

decode0(<<"M", Next/bitstring>>, Accu) ->

    decode0(Next, [<<20:5>>|Accu]);

decode0(<<"m", Next/bitstring>>, Accu) ->

    decode0(Next, [<<20:5>>|Accu]);

decode0(<<"N", Next/bitstring>>, Accu) ->

    decode0(Next, [<<21:5>>|Accu]);

decode0(<<"n", Next/bitstring>>, Accu) ->

    decode0(Next, [<<21:5>>|Accu]);

decode0(<<"P", Next/bitstring>>, Accu) ->

    decode0(Next, [<<22:5>>|Accu]);

decode0(<<"p", Next/bitstring>>, Accu) ->

    decode0(Next, [<<22:5>>|Accu]);

decode0(<<"Q", Next/bitstring>>, Accu) ->

    decode0(Next, [<<23:5>>|Accu]);

decode0(<<"q", Next/bitstring>>, Accu) ->

    decode0(Next, [<<23:5>>|Accu]);

decode0(<<"R", Next/bitstring>>, Accu) ->

    decode0(Next, [<<24:5>>|Accu]);

decode0(<<"r", Next/bitstring>>, Accu) ->

    decode0(Next, [<<24:5>>|Accu]);

decode0(<<"S", Next/bitstring>>, Accu) ->

    decode0(Next, [<<25:5>>|Accu]);

decode0(<<"s", Next/bitstring>>, Accu) ->

    decode0(Next, [<<25:5>>|Accu]);

decode0(<<"T", Next/bitstring>>, Accu) ->

    decode0(Next, [<<26:5>>|Accu]);

decode0(<<"t", Next/bitstring>>, Accu) ->

    decode0(Next, [<<26:5>>|Accu]);

decode0(<<"V", Next/bitstring>>, Accu) ->

    decode0(Next, [<<27:5>>|Accu]);

decode0(<<"v", Next/bitstring>>, Accu) ->

    decode0(Next, [<<27:5>>|Accu]);

decode0(<<"W", Next/bitstring>>, Accu) ->

    decode0(Next, [<<28:5>>|Accu]);

decode0(<<"w", Next/bitstring>>, Accu) ->

    decode0(Next, [<<28:5>>|Accu]);

decode0(<<"X", Next/bitstring>>, Accu) ->

    decode0(Next, [<<29:5>>|Accu]);

decode0(<<"x", Next/bitstring>>, Accu) ->

    decode0(Next, [<<29:5>>|Accu]);

decode0(<<"Y", Next/bitstring>>, Accu) ->

    decode0(Next, [<<30:5>>|Accu]);

decode0(<<"y", Next/bitstring>>, Accu) ->

    decode0(Next, [<<30:5>>|Accu]);

decode0(<<"Z", Next/bitstring>>, Accu) ->

    decode0(Next, [<<31:5>>|Accu]);

decode0(<<"z", Next/bitstring>>, Accu) ->

    decode0(Next, [<<31:5>>|Accu]);

decode0(<<"-", Next/bitstring>>, Accu) ->

    decode0(Next, Accu).