openethereum/util/src/rlp/rlpin.rs

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// Copyright 2015, 2016 Ethcore (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/>.
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use std::fmt;
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use rlp::{View, DecoderError, UntrustedRlp, PayloadInfo, Prototype, RlpDecodable};
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impl<'a> From<UntrustedRlp<'a>> for Rlp<'a> {
fn from(rlp: UntrustedRlp<'a>) -> Rlp<'a> {
Rlp { rlp: rlp }
}
}
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/// Data-oriented view onto trusted rlp-slice.
///
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/// Unlikely to `UntrustedRlp` doesn't bother you with error
/// handling. It assumes that you know what you are doing.
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#[derive(Debug)]
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pub struct Rlp<'a> {
rlp: UntrustedRlp<'a>
}
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impl<'a> fmt::Display for Rlp<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(f, "{}", self.rlp)
}
}
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impl<'a, 'view> View<'a, 'view> for Rlp<'a> where 'a: 'view {
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type Prototype = Prototype;
type PayloadInfo = PayloadInfo;
type Data = &'a [u8];
type Item = Rlp<'a>;
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type Iter = RlpIterator<'a, 'view>;
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/// Create a new instance of `Rlp`
fn new(bytes: &'a [u8]) -> Rlp<'a> {
Rlp {
rlp: UntrustedRlp::new(bytes)
}
}
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fn as_raw(&'view self) -> &'a [u8] {
self.rlp.as_raw()
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}
fn prototype(&self) -> Self::Prototype {
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self.rlp.prototype().unwrap()
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}
fn payload_info(&self) -> Self::PayloadInfo {
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self.rlp.payload_info().unwrap()
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}
fn data(&'view self) -> Self::Data {
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self.rlp.data().unwrap()
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}
fn item_count(&self) -> usize {
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self.rlp.item_count()
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}
fn size(&self) -> usize {
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self.rlp.size()
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}
fn at(&'view self, index: usize) -> Self::Item {
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From::from(self.rlp.at(index).unwrap())
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}
fn is_null(&self) -> bool {
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self.rlp.is_null()
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}
fn is_empty(&self) -> bool {
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self.rlp.is_empty()
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}
fn is_list(&self) -> bool {
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self.rlp.is_list()
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}
fn is_data(&self) -> bool {
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self.rlp.is_data()
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}
fn is_int(&self) -> bool {
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self.rlp.is_int()
}
fn iter(&'view self) -> Self::Iter {
self.into_iter()
}
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fn as_val<T>(&self) -> Result<T, DecoderError> where T: RlpDecodable {
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self.rlp.as_val()
}
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fn val_at<T>(&self, index: usize) -> Result<T, DecoderError> where T: RlpDecodable {
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self.at(index).rlp.as_val()
}
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}
impl <'a, 'view> Rlp<'a> where 'a: 'view {
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fn view_as_val<T, R>(r: &R) -> T where R: View<'a, 'view>, T: RlpDecodable {
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let res: Result<T, DecoderError> = r.as_val();
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res.unwrap_or_else(|e| panic!("DecodeError: {}", e))
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}
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/// Decode into an object
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pub fn as_val<T>(&self) -> T where T: RlpDecodable {
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Self::view_as_val(self)
}
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/// Decode list item at given index into an object
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pub fn val_at<T>(&self, index: usize) -> T where T: RlpDecodable {
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Self::view_as_val(&self.at(index))
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}
}
/// Iterator over trusted rlp-slice list elements.
pub struct RlpIterator<'a, 'view> where 'a: 'view {
rlp: &'view Rlp<'a>,
index: usize
}
impl<'a, 'view> IntoIterator for &'view Rlp<'a> where 'a: 'view {
type Item = Rlp<'a>;
type IntoIter = RlpIterator<'a, 'view>;
fn into_iter(self) -> Self::IntoIter {
RlpIterator {
rlp: self,
index: 0,
}
}
}
impl<'a, 'view> Iterator for RlpIterator<'a, 'view> {
type Item = Rlp<'a>;
fn next(&mut self) -> Option<Rlp<'a>> {
let index = self.index;
let result = self.rlp.rlp.at(index).ok().map(From::from);
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self.index += 1;
result
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}
}
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#[test]
fn break_it() {
use common::*;
let h: Bytes = FromHex::from_hex("f84d0589010efbef67941f79b2a056e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421a0c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470").unwrap();
let r: Rlp = Rlp::new(&h);
let u: U256 = r.val_at(1);
assert_eq!(format!("{}", u), "19526463837540678066");
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}