121 lines
4.0 KiB
Rust
121 lines
4.0 KiB
Rust
// Copyright 2015, 2016 Ethcore (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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//! Key-value datastore with a modified Merkle tree.
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extern crate rand;
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use bytes::*;
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use sha3::*;
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use hash::*;
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use rlp::encode;
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/// Alphabet to use when creating words for insertion into tries.
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pub enum Alphabet {
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/// All values are allowed in each bytes of the key.
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All,
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/// Only a 6 values ('a' - 'f') are chosen to compose the key.
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Low,
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/// Quite a few values (around 32) are chosen to compose the key.
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Mid,
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/// A set of bytes given is used to compose the key.
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Custom(Bytes),
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}
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/// Means of determining the value.
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pub enum ValueMode {
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/// Same as the key.
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Mirror,
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/// Randomly (50:50) 1 or 32 byte randomly string.
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Random,
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/// RLP-encoded index.
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Index,
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}
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/// Standard test map for profiling tries.
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pub struct StandardMap {
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/// The alphabet to use for keys.
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pub alphabet: Alphabet,
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/// Minimum size of key.
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pub min_key: usize,
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/// Delta size of key.
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pub journal_key: usize,
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/// Mode of value generation.
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pub value_mode: ValueMode,
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/// Number of keys.
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pub count: usize,
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}
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impl StandardMap {
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/// Get a bunch of random bytes, at least `min_count` bytes, at most `min_count` + `journal_count` bytes.
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/// `seed` is mutated pseudoramdonly and used.
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fn random_bytes(min_count: usize, journal_count: usize, seed: &mut H256) -> Vec<u8> {
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assert!(min_count + journal_count <= 32);
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*seed = seed.sha3();
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let r = min_count + (seed.bytes()[31] as usize % (journal_count + 1));
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seed.bytes()[0..r].to_vec()
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}
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/// Get a random value. Equal chance of being 1 byte as of 32. `seed` is mutated pseudoramdonly and used.
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fn random_value(seed: &mut H256) -> Bytes {
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*seed = seed.sha3();
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match seed.bytes()[0] % 2 {
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1 => vec![seed.bytes()[31];1],
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_ => seed.bytes().to_vec(),
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}
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}
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/// Get a random word of, at least `min_count` bytes, at most `min_count` + `journal_count` bytes.
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/// Each byte is an item from `alphabet`. `seed` is mutated pseudoramdonly and used.
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fn random_word(alphabet: &[u8], min_count: usize, journal_count: usize, seed: &mut H256) -> Vec<u8> {
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assert!(min_count + journal_count <= 32);
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*seed = seed.sha3();
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let r = min_count + (seed.bytes()[31] as usize % (journal_count + 1));
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let mut ret: Vec<u8> = Vec::with_capacity(r);
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for i in 0..r {
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ret.push(alphabet[seed.bytes()[i] as usize % alphabet.len()]);
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}
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ret
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}
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/// Create the standard map (set of keys and values) for the object's fields.
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pub fn make(&self) -> Vec<(Bytes, Bytes)> {
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self.make_with(&mut H256::new())
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}
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/// Create the standard map (set of keys and values) for the object's fields, using the given seed.
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pub fn make_with(&self, seed: &mut H256) -> Vec<(Bytes, Bytes)> {
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let low = b"abcdef";
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let mid = b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_";
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let mut d: Vec<(Bytes, Bytes)> = Vec::new();
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for index in 0..self.count {
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let k = match self.alphabet {
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Alphabet::All => Self::random_bytes(self.min_key, self.journal_key, seed),
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Alphabet::Low => Self::random_word(low, self.min_key, self.journal_key, seed),
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Alphabet::Mid => Self::random_word(mid, self.min_key, self.journal_key, seed),
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Alphabet::Custom(ref a) => Self::random_word(&a, self.min_key, self.journal_key, seed),
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};
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let v = match self.value_mode {
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ValueMode::Mirror => k.clone(),
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ValueMode::Random => Self::random_value(seed),
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ValueMode::Index => encode(&index).to_vec(),
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};
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d.push((k, v))
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}
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d
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}
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}
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