@polygon-hermez/vm
Version:
An Ethereum VM implementation
75 lines • 2.5 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const assert_1 = __importDefault(require("assert"));
const ethereumjs_util_1 = require("ethereumjs-util");
const BYTE_SIZE = 256;
class Bloom {
/**
* Represents a Bloom filter.
*/
constructor(bitvector) {
if (!bitvector) {
this.bitvector = (0, ethereumjs_util_1.zeros)(BYTE_SIZE);
}
else {
(0, assert_1.default)(bitvector.length === BYTE_SIZE, '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) {
(0, assert_1.default)(Buffer.isBuffer(e), 'Element should be buffer');
e = (0, ethereumjs_util_1.keccak256)(e);
const mask = 2047; // binary 11111111111
for (let i = 0; i < 3; i++) {
const first2bytes = e.readUInt16BE(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) {
(0, assert_1.default)(Buffer.isBuffer(e), 'Element should be Buffer');
e = (0, ethereumjs_util_1.keccak256)(e);
const mask = 2047; // binary 11111111111
let match = true;
for (let i = 0; i < 3 && match; i++) {
const first2bytes = e.readUInt16BE(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) {
if (bloom) {
for (let i = 0; i <= BYTE_SIZE; i++) {
this.bitvector[i] = this.bitvector[i] | bloom.bitvector[i];
}
}
}
}
exports.default = Bloom;
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