openethereum/util/rlp/src/lib.rs

// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

//! Recursive Length Prefix serialization crate.
//!
//! Allows encoding, decoding, and view onto rlp-slice
//!
//!# What should you use when?
//!
//!### Use `encode` function when:
//! * You want to encode something inline.
//! * You do not work on big set of data.
//! * You want to encode whole data structure at once.
//!
//!### Use `decode` function when:
//! * You want to decode something inline.
//! * You do not work on big set of data.
//! * You want to decode whole rlp at once.
//!
//!### Use `RlpStream` when:
//! * You want to encode something in portions.
//! * You encode a big set of data.
//!
//!### Use `Rlp` when:
//! * You are working on trusted data (not corrupted).
//! * You want to get view onto rlp-slice.
//! * You don't want to decode whole rlp at once.
//!
//!### Use `UntrustedRlp` when:
//! * You are working on untrusted data (~corrupted).
//! * You need to handle data corruption errors.
//! * You are working on input data.
//! * You want to get view onto rlp-slice.
//! * You don't want to decode whole rlp at once.

pub mod rlptraits;
mod rlperrors;
mod rlpin;
mod untrusted_rlp;
mod rlpstream;
mod rlpcompression;
mod commonrlps;
mod bytes;

#[cfg(test)]
mod tests;

pub use self::rlperrors::DecoderError;
pub use self::rlptraits::{Decoder, Decodable, View, Stream, Encodable, Encoder, RlpEncodable, RlpDecodable, Compressible};
pub use self::untrusted_rlp::{UntrustedRlp, UntrustedRlpIterator, PayloadInfo, Prototype};
pub use self::rlpin::{Rlp, RlpIterator};
pub use self::rlpstream::RlpStream;
pub use self::rlpcompression::RlpType;

extern crate ethcore_bigint as bigint;
extern crate elastic_array;
extern crate rustc_serialize;

#[macro_use]
extern crate lazy_static;

use elastic_array::ElasticArray1024;

/// The RLP encoded empty data (used to mean "null value").
pub const NULL_RLP: [u8; 1] = [0x80; 1];
/// The RLP encoded empty list.
pub const EMPTY_LIST_RLP: [u8; 1] = [0xC0; 1];

/// Shortcut function to decode trusted rlp
///
/// ```rust
/// extern crate rlp;
///
/// fn main () {
/// 	let data = vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g'];
/// 	let animals: Vec<String> = rlp::decode(&data);
/// 	assert_eq!(animals, vec!["cat".to_string(), "dog".to_string()]);
/// }
/// ```
pub fn decode<T>(bytes: &[u8]) -> T where T: RlpDecodable {
	let rlp = Rlp::new(bytes);
	rlp.as_val()
}

/// Shortcut function to encode structure into rlp.
///
/// ```rust
/// extern crate rlp;
///
/// fn main () {
/// 	let animal = "cat";
/// 	let out = rlp::encode(&animal).to_vec();
/// 	assert_eq!(out, vec![0x83, b'c', b'a', b't']);
/// }
/// ```
pub fn encode<E>(object: &E) -> ElasticArray1024<u8> where E: RlpEncodable {
	let mut stream = RlpStream::new();
	stream.append(object);
	stream.drain()
}