openethereum/ethcore/src/blockchain/bloom_indexer.rs
2016-03-01 00:44:45 +03:00

103 lines
2.7 KiB
Rust

// 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/>.
use util::numbers::H256;
use chainfilter::BloomIndex;
/// Represents location of block bloom in extras database.
#[derive(Debug, PartialEq)]
pub struct BlocksBloomLocation {
/// Unique hash of BlocksBloom
pub hash: H256,
/// Index within BlocksBloom
pub index: usize,
}
/// Should be used to localize blocks blooms in extras database.
pub struct BloomIndexer {
index_size: usize,
levels: u8,
}
impl BloomIndexer {
/// Plain constructor.
pub fn new(index_size: usize, levels: u8) -> Self {
BloomIndexer {
index_size: index_size,
levels: levels
}
}
/// Calculates bloom's position in database.
pub fn location(&self, bloom_index: &BloomIndex) -> BlocksBloomLocation {
use std::{mem, ptr};
let hash = unsafe {
let mut hash: H256 = mem::zeroed();
ptr::copy(&[bloom_index.index / self.index_size] as *const usize as *const u8, hash.as_mut_ptr(), 8);
hash[8] = bloom_index.level;
hash.reverse();
hash
};
BlocksBloomLocation {
hash: hash,
index: bloom_index.index % self.index_size
}
}
/// Returns index size.
pub fn index_size(&self) -> usize {
self.index_size
}
/// Returns number of cache levels.
pub fn levels(&self) -> u8 {
self.levels
}
}
#[cfg(test)]
mod tests {
use std::str::FromStr;
use util::hash::{H256, FixedHash};
use chainfilter::BloomIndex;
use blockchain::bloom_indexer::{BloomIndexer, BlocksBloomLocation};
#[test]
fn test_bloom_indexer() {
let bi = BloomIndexer::new(16, 3);
let index = BloomIndex::new(0, 0);
assert_eq!(bi.location(&index), BlocksBloomLocation {
hash: H256::new(),
index: 0
});
let index = BloomIndex::new(1, 0);
assert_eq!(bi.location(&index), BlocksBloomLocation {
hash: H256::from_str("0000000000000000000000000000000000000000000000010000000000000000").unwrap(),
index: 0
});
let index = BloomIndex::new(0, 299_999);
assert_eq!(bi.location(&index), BlocksBloomLocation {
hash: H256::from_str("000000000000000000000000000000000000000000000000000000000000493d").unwrap(),
index: 15
});
}
}