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lib/ibento/base32crockford.ex
defmodule Ibento.Base32Crockford do
defguardp is_iodata(i) when is_binary(i) or is_list(i)
defmacrop to_binary(i) do
quote do
case unquote(i) do
_ when is_binary(unquote(i)) ->
unquote(i)
_ when is_list(unquote(i)) ->
:erlang.iolist_to_binary(unquote(i))
end
end
end
defmacrop lc_b32crockford_to_int(c) do
quote do
case unquote(c) do
?0 -> 0x00
?1 -> 0x01
?2 -> 0x02
?3 -> 0x03
?4 -> 0x04
?5 -> 0x05
?6 -> 0x06
?7 -> 0x07
?8 -> 0x08
?9 -> 0x09
?a -> 0x0A
?b -> 0x0B
?c -> 0x0C
?d -> 0x0D
?e -> 0x0E
?f -> 0x0F
?g -> 0x10
?h -> 0x11
?j -> 0x12
?k -> 0x13
?m -> 0x14
?n -> 0x15
?p -> 0x16
?q -> 0x17
?r -> 0x18
?s -> 0x19
?t -> 0x1A
?v -> 0x1B
?w -> 0x1C
?x -> 0x1D
?y -> 0x1E
?z -> 0x1F
end
end
end
defmacrop mc_b32crockford_to_int(c) do
quote do
case unquote(c) do
?0 -> 0x00
?1 -> 0x01
?2 -> 0x02
?3 -> 0x03
?4 -> 0x04
?5 -> 0x05
?6 -> 0x06
?7 -> 0x07
?8 -> 0x08
?9 -> 0x09
?a -> 0x0A
?b -> 0x0B
?c -> 0x0C
?d -> 0x0D
?e -> 0x0E
?f -> 0x0F
?g -> 0x10
?h -> 0x11
?j -> 0x12
?k -> 0x13
?m -> 0x14
?n -> 0x15
?p -> 0x16
?q -> 0x17
?r -> 0x18
?s -> 0x19
?t -> 0x1A
?v -> 0x1B
?w -> 0x1C
?x -> 0x1D
?y -> 0x1E
?z -> 0x1F
?A -> 0x0A
?B -> 0x0B
?C -> 0x0C
?D -> 0x0D
?E -> 0x0E
?F -> 0x0F
?G -> 0x10
?H -> 0x11
?J -> 0x12
?K -> 0x13
?M -> 0x14
?N -> 0x15
?P -> 0x16
?Q -> 0x17
?R -> 0x18
?S -> 0x19
?T -> 0x1A
?V -> 0x1B
?W -> 0x1C
?X -> 0x1D
?Y -> 0x1E
?Z -> 0x1F
end
end
end
defmacrop uc_b32crockford_to_int(c) do
quote do
case unquote(c) do
?0 -> 0x00
?1 -> 0x01
?2 -> 0x02
?3 -> 0x03
?4 -> 0x04
?5 -> 0x05
?6 -> 0x06
?7 -> 0x07
?8 -> 0x08
?9 -> 0x09
?A -> 0x0A
?B -> 0x0B
?C -> 0x0C
?D -> 0x0D
?E -> 0x0E
?F -> 0x0F
?G -> 0x10
?H -> 0x11
?J -> 0x12
?K -> 0x13
?M -> 0x14
?N -> 0x15
?P -> 0x16
?Q -> 0x17
?R -> 0x18
?S -> 0x19
?T -> 0x1A
?V -> 0x1B
?W -> 0x1C
?X -> 0x1D
?Y -> 0x1E
?Z -> 0x1F
end
end
end
defmacrop lc_int_to_b32crockford(c) do
quote do
case unquote(c) do
0x00 -> ?0
0x01 -> ?1
0x02 -> ?2
0x03 -> ?3
0x04 -> ?4
0x05 -> ?5
0x06 -> ?6
0x07 -> ?7
0x08 -> ?8
0x09 -> ?9
0x0A -> ?a
0x0B -> ?b
0x0C -> ?c
0x0D -> ?d
0x0E -> ?e
0x0F -> ?f
0x10 -> ?g
0x11 -> ?h
0x12 -> ?j
0x13 -> ?k
0x14 -> ?m
0x15 -> ?n
0x16 -> ?p
0x17 -> ?q
0x18 -> ?r
0x19 -> ?s
0x1A -> ?t
0x1B -> ?v
0x1C -> ?w
0x1D -> ?x
0x1E -> ?y
0x1F -> ?z
end
end
end
defmacrop uc_int_to_b32crockford(c) do
quote do
case unquote(c) do
0x00 -> ?0
0x01 -> ?1
0x02 -> ?2
0x03 -> ?3
0x04 -> ?4
0x05 -> ?5
0x06 -> ?6
0x07 -> ?7
0x08 -> ?8
0x09 -> ?9
0x0A -> ?A
0x0B -> ?B
0x0C -> ?C
0x0D -> ?D
0x0E -> ?E
0x0F -> ?F
0x10 -> ?G
0x11 -> ?H
0x12 -> ?J
0x13 -> ?K
0x14 -> ?M
0x15 -> ?N
0x16 -> ?P
0x17 -> ?Q
0x18 -> ?R
0x19 -> ?S
0x1A -> ?T
0x1B -> ?V
0x1C -> ?W
0x1D -> ?X
0x1E -> ?Y
0x1F -> ?Z
end
end
end
def decode(input) when is_iodata(input) do
decode(input, %{})
end
def decode(input, opts) when is_iodata(input) and is_map(opts) do
try do
decode!(input, opts)
catch
_, _ ->
:error
else
output when is_binary(output) ->
{:ok, output}
end
end
def decode(input, opts) when is_iodata(input) and is_list(opts) do
decode(input, :maps.from_list(opts))
end
def decode!(input) when is_iodata(input) do
decode!(input, %{})
end
def decode!([], %{}) do
<<>>
end
def decode!(<<>>, %{}) do
<<>>
end
def decode!(input, opts) when is_iodata(input) and is_map(opts) do
ccase = Map.get(opts, :case, :mixed)
padding = Map.get(opts, :padding, nil)
size = :erlang.iolist_size(input)
offset =
case padding do
_ when (padding == false or is_nil(padding)) and size <= 8 ->
0
_ when (padding == false or is_nil(padding)) and rem(size, 8) === 0 ->
size - 8
_ when (padding == false or is_nil(padding)) and rem(size, 8) !== 0 ->
size - rem(size, 8)
_ when (padding == true or is_nil(padding)) and size >= 8 ->
size - 8
_ ->
:erlang.error({:badarg, [input, opts]})
end
<<head0::binary-size(offset), tail0::bitstring()>> = to_binary(input)
tail1 =
case padding do
false ->
case tail0 do
<<t0::binary-size(1), t1::8>> ->
{t0, t1, 2, 3}
<<t0::binary-size(3), t1::8>> ->
{t0, t1, 4, 1}
<<t0::binary-size(4), t1::8>> ->
{t0, t1, 1, 4}
<<t0::binary-size(6), t1::8>> ->
{t0, t1, 3, 2}
<<>> ->
<<>>
_ ->
:erlang.error({:badarg, [input, opts]})
end
nil ->
case tail0 do
<<t0::binary-size(1), t1::8, ?=, ?=, ?=, ?=, ?=, ?=>> ->
{t0, t1, 2, 3}
<<t0::binary-size(3), t1::8, ?=, ?=, ?=, ?=>> ->
{t0, t1, 4, 1}
<<t0::binary-size(4), t1::8, ?=, ?=, ?=>> ->
{t0, t1, 1, 4}
<<t0::binary-size(6), t1::8, ?=>> ->
{t0, t1, 3, 2}
<<t0::binary-size(1), t1::8>> ->
{t0, t1, 2, 3}
<<t0::binary-size(3), t1::8>> ->
{t0, t1, 4, 1}
<<t0::binary-size(4), t1::8>> ->
{t0, t1, 1, 4}
<<t0::binary-size(6), t1::8>> ->
{t0, t1, 3, 2}
<<t0::binary-size(8)>> ->
t0
<<>> ->
<<>>
end
true ->
case tail0 do
<<t0::binary-size(1), t1::8, ?=, ?=, ?=, ?=, ?=, ?=>> ->
{t0, t1, 2, 3}
<<t0::binary-size(3), t1::8, ?=, ?=, ?=, ?=>> ->
{t0, t1, 4, 1}
<<t0::binary-size(4), t1::8, ?=, ?=, ?=>> ->
{t0, t1, 1, 4}
<<t0::binary-size(6), t1::8, ?=>> ->
{t0, t1, 3, 2}
_ ->
:erlang.error({:badarg, [input, opts]})
end
end
{head, tail} =
case ccase do
:lower ->
h = for <<v <- head0>>, into: <<>>, do: <<lc_b32crockford_to_int(v)::5>>
t =
case tail1 do
<<>> ->
<<>>
_ when is_binary(tail1) ->
for <<v <- tail1>>, into: <<>>, do: <<lc_b32crockford_to_int(v)::5>>
{tail2, last0, bitshift, bits} ->
tail3 = for <<v <- tail2>>, into: <<>>, do: <<lc_b32crockford_to_int(v)::5>>
last = :erlang.bsr(lc_b32crockford_to_int(last0), bitshift)
<<tail3::bitstring(), last::size(bits)>>
end
{h, t}
:mixed ->
h = for <<v <- head0>>, into: <<>>, do: <<mc_b32crockford_to_int(v)::5>>
t =
case tail1 do
<<>> ->
<<>>
_ when is_binary(tail1) ->
for <<v <- tail1>>, into: <<>>, do: <<mc_b32crockford_to_int(v)::5>>
{tail2, last0, bitshift, bits} ->
tail3 = for <<v <- tail2>>, into: <<>>, do: <<mc_b32crockford_to_int(v)::5>>
last = :erlang.bsr(mc_b32crockford_to_int(last0), bitshift)
<<tail3::bitstring(), last::size(bits)>>
end
{h, t}
:upper ->
h = for <<v <- head0>>, into: <<>>, do: <<uc_b32crockford_to_int(v)::5>>
t =
case tail1 do
<<>> ->
<<>>
_ when is_binary(tail1) ->
for <<v <- tail1>>, into: <<>>, do: <<uc_b32crockford_to_int(v)::5>>
{tail2, last0, bitshift, bits} ->
tail3 = for <<v <- tail2>>, into: <<>>, do: <<uc_b32crockford_to_int(v)::5>>
last = :erlang.bsr(uc_b32crockford_to_int(last0), bitshift)
<<tail3::bitstring(), last::size(bits)>>
end
{h, t}
_ ->
:erlang.error({:badarg, [input, opts]})
end
<<head::bitstring(), tail::bitstring()>>
end
def decode!(input, opts) when is_iodata(input) and is_list(opts) do
decode!(input, :maps.from_list(opts))
end
def encode(input) when is_iodata(input) do
encode(input, %{})
end
def encode(input, opts) when is_iodata(input) and is_map(opts) do
ccase = Map.get(opts, :case, :upper)
padding = Map.get(opts, :padding, true)
offset = 5 * div(:erlang.iolist_size(input) * 8, 5)
<<head::bitstring-size(offset), tail::bitstring()>> = to_binary(input)
case ccase do
:lower when is_boolean(padding) ->
h = for <<v::5 <- head>>, into: <<>>, do: <<lc_int_to_b32crockford(v)>>
{t, pad} =
case tail do
<<v::1>> -> {<<lc_int_to_b32crockford(:erlang.bsl(v, 4))>>, 4}
<<v::2>> -> {<<lc_int_to_b32crockford(:erlang.bsl(v, 3))>>, 1}
<<v::3>> -> {<<lc_int_to_b32crockford(:erlang.bsl(v, 2))>>, 6}
<<v::4>> -> {<<lc_int_to_b32crockford(:erlang.bsl(v, 1))>>, 3}
<<>> -> {<<>>, 0}
end
case padding do
true ->
<<h::binary(), t::binary(), :binary.copy(<<?=>>, pad)::binary()>>
false ->
<<h::binary(), t::binary()>>
end
:upper when is_boolean(padding) ->
h = for <<v::5 <- head>>, into: <<>>, do: <<uc_int_to_b32crockford(v)>>
{t, pad} =
case tail do
<<v::1>> -> {<<uc_int_to_b32crockford(:erlang.bsl(v, 4))>>, 4}
<<v::2>> -> {<<uc_int_to_b32crockford(:erlang.bsl(v, 3))>>, 1}
<<v::3>> -> {<<uc_int_to_b32crockford(:erlang.bsl(v, 2))>>, 6}
<<v::4>> -> {<<uc_int_to_b32crockford(:erlang.bsl(v, 1))>>, 3}
<<>> -> {<<>>, 0}
end
case padding do
true ->
<<h::binary(), t::binary(), :binary.copy(<<?=>>, pad)::binary()>>
false ->
<<h::binary(), t::binary()>>
end
_ ->
:erlang.error({:badarg, [input, opts]})
end
end
def encode(input, opts) when is_iodata(input) and is_list(opts) do
encode(input, :maps.from_list(opts))
end
end