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Change default encoding to binary, instead of hex #3

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Aug 2, 2017
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Change default encoding to binary, instead of hex #3

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4d2f761
Change default encoding to binary, instead of hex
hayesgm Aug 1, 2017
da259cb
Bump to 0.2.0
hayesgm Aug 1, 2017
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52 changes: 25 additions & 27 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -27,17 +27,23 @@ And run:
Use ExRLP.encode/1 method to encode an item to RLP representation. An item can be nonnegative integer, binary or list. List can contain integers, binaries or lists.

```elixir

## Examples

iex(1)> "dog" |> ExRLP.encode
"83646f67"

iex(2)> 1000 |> ExRLP.encode
"8203e8"

iex(3)> [ [ [], [] ], [] ] |> ExRLP.encode
"c4c2c0c0c0"
iex(1)> "dog" |> ExRLP.encode(encoding: :hex)
"83646f67"

iex(2)> "dog" |> ExRLP.encode(encoding: :binary)
<<0x83, 0x64, 0x6f, 0x67>>

iex(3)> 1000 |> ExRLP.encode(encoding: :hex)
"8203e8"

# Default encoding is binary
iex(3)> 1000 |> ExRLP.encode
<<0x82, 0x03, 0xe8>>

iex(4)> [ [ [], [] ], [] ] |> ExRLP.encode(encoding: :hex)
"c4c2c0c0c0"
```

Use ExRLP.decode/1 method to decode a rlp encoded data. All items except lists are decoded as binaries so additional deserialization is needed if initially an item of another type was encoded.
Expand All @@ -47,14 +53,14 @@ Use ExRLP.decode/1 method to decode a rlp encoded data. All items except lists a

## Examples

iex(1)> "83646f67" |> ExRLP.decode
"dog"
iex(2)> "8203e8" |> ExRLP.decode |> :binary.decode_unsigned
1000
iex(3)> "c4c2c0c0c0" |> ExRLP.decode
[[[], []], []]
iex(1)> "83646f67" |> ExRLP.decode(:binary, encoding: :hex)
"dog"

iex(2)> "8203e8" |> ExRLP.decode(:binary, encoding: :hex) |> :binary.decode_unsigned
1000

iex(3)> "c4c2c0c0c0" |> ExRLP.decode(:binary, encoding: :hex)
[[[], []], []]
```

More examples can be found in test files.
Expand All @@ -70,10 +76,6 @@ Custom protocols for Map have already been implemented in ExRLP:
defimpl ExRLP.Encoder, for: Map do
alias ExRLP.Encode

def encode(map, _) when map_size(map) < 1 do
"827b7d"
end

def encode(map, _) do
map
|> Map.keys
Expand All @@ -89,10 +91,6 @@ end
defimpl ExRLP.Decoder, for: BitString do
alias ExRLP.Decode

def decode("827b7d", :map, _) do
%{}
end

def decode(value, :map, options) do
keys =
options
Expand All @@ -114,10 +112,10 @@ end
```
So now it's possible to encode/decode maps:
```elixir
iex(1)> %{name: "Vitalik", surname: "Buterin"} |> ExRLP.encode
iex(1)> %{name: "Vitalik", surname: "Buterin"} |> ExRLP.encode(encoding: :hex)
"d087566974616c696b874275746572696e"

iex(2)> "d087566974616c696b874275746572696e" |> ExRLP.decode(:map, keys: [:surname, :name])
iex(2)> "d087566974616c696b874275746572696e" |> ExRLP.decode(:map, keys: [:surname, :name], encoding: :hex)
%{name: "Vitalik", surname: "Buterin"}
```

Expand Down
99 changes: 96 additions & 3 deletions lib/ex_rlp.ex
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Original file line number Diff line number Diff line change
Expand Up @@ -3,11 +3,104 @@ defmodule ExRLP do

@moduledoc File.read!("#{__DIR__}/../README.md")

def encode(item, options \\ nil) do
@type t :: nil | [t] | binary()

@doc """
Given an RLP structure, returns the encoding as a string.

## Examples

iex> ExRLP.encode("dog")
<<0x83, ?d, ?o, ?g>>

iex> ExRLP.encode("dog", encoding: :hex)
"83646f67"

iex> ExRLP.encode(Enum.join(for _ <- 1..60, do: "A"))
<<184, 60, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65>>

iex> ExRLP.encode(["cat", "dog"])
<<0xc8, 0x83, ?c, ?a, ?t, 0x83, ?d, ?o, ?g>>

iex> ExRLP.encode("")
<<0x80>>

iex> ExRLP.encode([])
<<0xc0>>

iex> ExRLP.encode("\x0f")
<<0x0f>>

iex> ExRLP.encode(15)
<<0x0f>>

iex> ExRLP.encode(15_000_000_000_000_000_000_000_000_000_000_000)
<<143, 2, 227, 142, 158, 4, 75, 160, 83, 84, 85, 150, 0, 0, 0, 0>>

iex> ExRLP.encode(1024)
<<0x82, 0x04, 0x00>>

iex> ExRLP.encode("\x04\x00")
<<0x82, 0x04, 0x00>>

iex> ExRLP.encode([[],[[]],[[],[[]]]])
<<0xc7, 0xc0, 0xc1, 0xc0, 0xc3, 0xc0, 0xc1, 0xc0>>

iex> ExRLP.encode(for _ <- 1..60, do: [])
<<248, 60, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192>>
"""
@spec encode(t, keyword()) :: binary()
def encode(item, options \\ []) do
item |> Encoder.encode(options)
end

def decode(item, type \\ :binary, options \\ nil) do
@doc """
Given an RLP-encoded string, returns a decoded RPL structure (which is an array of RLP structures or binaries).

## Examples

iex> ExRLP.decode(<<>>)
nil

iex> ExRLP.decode(<<0x83, ?d, ?o, ?g>>)
"dog"

iex> ExRLP.decode("83646f67", :binary, encoding: :hex)
"dog"

iex> ExRLP.decode(<<184, 60, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65>>)
Enum.join(for _ <- 1..60, do: "A")

iex> ExRLP.decode(<<0xc8, 0x83, ?c, ?a, ?t, 0x83, ?d, ?o, ?g>>)
["cat", "dog"]

iex> ExRLP.decode(<<198, 51, 132, 99, 111, 111, 108>>)
["3", "cool"]

iex> ExRLP.decode(<<0x80>>)
""

iex> ExRLP.decode(<<0xc0>>)
[]

iex> ExRLP.decode(<<0x0f>>)
<<0x0f>>

iex> ExRLP.decode(<<0x82, 0x04, 0x00>>)
"\x04\x00"

iex> ExRLP.decode(<<0xc7, 0xc0, 0xc1, 0xc0, 0xc3, 0xc0, 0xc1, 0xc0>>)
[[],[[]],[[],[[]]]]

iex> ExRLP.decode(<<248, 60, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192, 192>>)
for _ <- 1..60, do: []

iex> ExRLP.decode(<<143, 2, 227, 142, 158, 4, 75, 160, 83, 84, 85, 150, 0, 0, 0, 0>>) |> :binary.decode_unsigned
15_000_000_000_000_000_000_000_000_000_000_000
"""
@spec decode(binary(), atom(), keyword()) :: t
def decode(item, type \\ :binary, options \\ []) do
item |> Decoder.decode(type, options)
end
end

end
29 changes: 19 additions & 10 deletions lib/ex_rlp/decoder.ex
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Original file line number Diff line number Diff line change
@@ -1,12 +1,18 @@
defmodule ExRLP.Decode do
@moduledoc false

def decode(item) when is_binary(item) do
@spec decode(binary(), :binary | :hex) :: ExRLP.t
def decode(item, encoding) when is_binary(item) do
item
|> decode_hex
|> maybe_decode_hex(encoding)
|> decode_item
end

@spec maybe_decode_hex(binary(), atom()) :: binary()
defp maybe_decode_hex(value, :binary), do: value
defp maybe_decode_hex(value, :hex), do: decode_hex(value)

@spec decode_item(binary(), ExRLP.t) :: ExRLP.t
defp decode_item(rlp_binary, result \\ nil)

defp decode_item("", result) do
Expand Down Expand Up @@ -61,6 +67,7 @@ defmodule ExRLP.Decode do
decode_item(new_tail, new_result)
end

@spec add_new_item(ExRLP.t, ExRLP.t) :: ExRLP.t
def add_new_item(nil, new_item) do
new_item
end
Expand All @@ -69,6 +76,7 @@ defmodule ExRLP.Decode do
result ++ [new_item]
end

@spec add_decoded_list(ExRLP.t, binary()) :: ExRLP.t
defp add_decoded_list(nil, rlp_list_binary) do
decode_item(rlp_list_binary, [])
end
Expand All @@ -79,13 +87,15 @@ defmodule ExRLP.Decode do
result ++ [list_items]
end

@spec decode_medium_binary(integer(), binary(), integer()) :: {binary(), binary()}
defp decode_medium_binary(length_prefix, tail, prefix) do
item_length = length_prefix - prefix
<< item :: binary-size(item_length), new_tail :: binary >> = tail

{item, new_tail}
end

@spec decode_long_binary(integer(), binary(), integer()) :: {binary(), binary()}
defp decode_long_binary(be_size_prefix, tail, prefix) do
be_size = be_size_prefix - prefix
<< be :: binary-size(be_size), data :: binary >> = tail
Expand All @@ -96,6 +106,7 @@ defmodule ExRLP.Decode do
{item, new_tail}
end

@spec decode_hex(binary()) :: binary()
defp decode_hex(binary) do
{:ok, decoded_binary} = binary |> Base.decode16(case: :lower)

Expand All @@ -110,18 +121,16 @@ end
defimpl ExRLP.Decoder, for: BitString do
alias ExRLP.Decode

def decode("827b7d", :map, _) do
%{}
end

@spec decode(binary(), atom(), keyword()) :: ExRLP.t
def decode(value, type \\ :binary, options \\ [])
def decode(value, :map, options) do
keys =
options
|> Keyword.fetch!(:keys)
|> Keyword.get(:keys, [])
|> Enum.sort

value
|> Decode.decode
|> Decode.decode(Keyword.get(options, :encoding, :binary))
|> Enum.with_index
|> Enum.reduce(%{}, fn({value, index}, acc) ->
key = keys |> Enum.at(index)
Expand All @@ -130,7 +139,7 @@ defimpl ExRLP.Decoder, for: BitString do
end)
end

def decode(value, :binary, _) do
value |> Decode.decode
def decode(value, :binary, options) do
value |> Decode.decode(Keyword.get(options, :encoding, :binary))
end
end
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