70 lines
2.7 KiB
Rust
70 lines
2.7 KiB
Rust
// Copyright 2015-2018 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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use elastic_array::ElasticArray36;
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use nibbleslice::NibbleSlice;
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use nibblevec::NibbleVec;
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use hashdb::DBValue;
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/// Partial node key type.
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pub type NodeKey = ElasticArray36<u8>;
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/// Type of node in the trie and essential information thereof.
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#[derive(Eq, PartialEq, Debug, Clone)]
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pub enum Node<'a> {
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/// Null trie node; could be an empty root or an empty branch entry.
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Empty,
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/// Leaf node; has key slice and value. Value may not be empty.
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Leaf(NibbleSlice<'a>, &'a [u8]),
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/// Extension node; has key slice and node data. Data may not be null.
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Extension(NibbleSlice<'a>, &'a [u8]),
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/// Branch node; has array of 16 child nodes (each possibly null) and an optional immediate node data.
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Branch([&'a [u8]; 16], Option<&'a [u8]>),
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}
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/// An owning node type. Useful for trie iterators.
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#[derive(Debug, PartialEq, Eq)]
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pub enum OwnedNode {
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/// Empty trie node.
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Empty,
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/// Leaf node: partial key and value.
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Leaf(NibbleVec, DBValue),
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/// Extension node: partial key and child node.
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Extension(NibbleVec, DBValue),
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/// Branch node: 16 children and an optional value.
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Branch([NodeKey; 16], Option<DBValue>),
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}
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impl<'a> From<Node<'a>> for OwnedNode {
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fn from(node: Node<'a>) -> Self {
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match node {
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Node::Empty => OwnedNode::Empty,
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Node::Leaf(k, v) => OwnedNode::Leaf(k.into(), DBValue::from_slice(v)),
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Node::Extension(k, child) => OwnedNode::Extension(k.into(), DBValue::from_slice(child)),
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Node::Branch(c, val) => {
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let children = [
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NodeKey::from_slice(c[0]), NodeKey::from_slice(c[1]), NodeKey::from_slice(c[2]), NodeKey::from_slice(c[3]),
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NodeKey::from_slice(c[4]), NodeKey::from_slice(c[5]), NodeKey::from_slice(c[6]), NodeKey::from_slice(c[7]),
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NodeKey::from_slice(c[8]), NodeKey::from_slice(c[9]), NodeKey::from_slice(c[10]), NodeKey::from_slice(c[11]),
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NodeKey::from_slice(c[12]), NodeKey::from_slice(c[13]), NodeKey::from_slice(c[14]), NodeKey::from_slice(c[15]),
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];
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OwnedNode::Branch(children, val.map(DBValue::from_slice))
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}
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}
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}
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}
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