Elixir implementation of Ethereum's RLP (Recursive Length Prefix) encoding.
The encoding's specification can be found in the yellow paper or in the ethereum wiki.
The easiest way to add ExRLP to your project is by using Mix.
Add :ex_rlp as a dependency to your project's mix.exs:
defp deps do
[
{:ex_rlp, "~> 0.6.0"}
]
endAnd run:
$ mix deps.getUse ExRLP.encode/1 method to encode an item to RLP representation. An item can be non-negative integer, binary or list. List can contain integers, binaries or lists.
iex> "dog" |> ExRLP.encode(encoding: :hex)
"83646f67"
iex> "dog" |> ExRLP.encode(encoding: :binary)
<<0x83, 0x64, 0x6f, 0x67>>
iex> 1000 |> ExRLP.encode(encoding: :hex)
"8203e8"
# Default encoding is binary
iex> 1000 |> ExRLP.encode
<<0x82, 0x03, 0xe8>>
iex> [ [ [], [] ], [] ] |> 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.
iex> "83646f67" |> ExRLP.decode(encoding: :hex)
"dog"
iex> "8203e8" |> ExRLP.decode(encoding: :hex) |> :binary.decode_unsigned
1000
iex> "c4c2c0c0c0" |> ExRLP.decode(encoding: :hex)
[[[], []], []]More examples can be found in test files.
You can define protocols for encoding/decoding custom data types.
defmodule ExRLP.LogEntry do
defstruct address: nil, topics: [], data: nil
@type t :: %__MODULE__{
address: EVM.address(),
topics: [integer()],
data: binary()
}
@spec new(binary, [integer()], binary()) :: t()
def new(address, topics, data) do
%__MODULE__{
address: address,
topics: topics,
data: data
}
end
def to_list(log) do
[log.address, log.topics, log.data]
end
end
defimpl ExRLP.Encode, for: ExRLP.LogEntry do
alias ExRLP.{Encode, LogEntry}
@spec encode(LogEntry.t(), keyword()) :: binary()
def encode(log, options \\ []) do
log
|> LogEntry.to_list()
|> Encode.encode(options)
end
end- Fork it!
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request
Ayrat Badykov (@ayrat555)
Copyright (c) 2017 Geoffrey Hayes, Ayrat Badykov, Mason Forest
ExRLP is released under the MIT License. See the LICENSE.md file for further details.