@ethereumjs/vm
Version:
An Ethereum VM implementation
72 lines • 2.32 kB
JavaScript
import { EthereumJSErrorWithoutCode } from '@ethereumjs/util';
import { keccak256 } from 'ethereum-cryptography/keccak.js';
const BYTE_SIZE = 256;
export class Bloom {
/**
* Represents a Bloom filter.
*/
constructor(bitvector, common) {
if (common?.customCrypto.keccak256 !== undefined) {
this.keccakFunction = common.customCrypto.keccak256;
}
else {
this.keccakFunction = keccak256;
}
if (!bitvector) {
this.bitvector = new Uint8Array(BYTE_SIZE);
}
else {
if (bitvector.length !== BYTE_SIZE)
throw EthereumJSErrorWithoutCode('bitvectors must be 2048 bits long');
this.bitvector = bitvector;
}
}
/**
* Adds an element to a bit vector of a 64 byte bloom filter.
* @param e - The element to add
*/
add(e) {
e = this.keccakFunction(e);
const mask = 2047; // binary 11111111111
for (let i = 0; i < 3; i++) {
const first2bytes = new DataView(e.buffer).getUint16(i * 2);
const loc = mask & first2bytes;
const byteLoc = loc >> 3;
const bitLoc = 1 << (loc % 8);
this.bitvector[BYTE_SIZE - byteLoc - 1] |= bitLoc;
}
}
/**
* Checks if an element is in the bloom.
* @param e - The element to check
*/
check(e) {
e = this.keccakFunction(e);
const mask = 2047; // binary 11111111111
let match = true;
for (let i = 0; i < 3 && match; i++) {
const first2bytes = new DataView(e.buffer).getUint16(i * 2);
const loc = mask & first2bytes;
const byteLoc = loc >> 3;
const bitLoc = 1 << (loc % 8);
match = (this.bitvector[BYTE_SIZE - byteLoc - 1] & bitLoc) !== 0;
}
return Boolean(match);
}
/**
* Checks if multiple topics are in a bloom.
* @returns `true` if every topic is in the bloom
*/
multiCheck(topics) {
return topics.every((t) => this.check(t));
}
/**
* Bitwise or blooms together.
*/
or(bloom) {
for (let i = 0; i <= BYTE_SIZE; i++) {
this.bitvector[i] = this.bitvector[i] | bloom.bitvector[i];
}
}
}
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