Press n or j to go to the next uncovered block, b, p or k for the previous block.
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This file is part of susyweb.js.
susyweb.js is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
susyweb.js is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MSRCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with susyweb.js. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file bloom.js
* @author Bas van Kervel <bas@ethereum.org>
* @date 2017
*/
/**
* Sophon bloom filter support.
*
* TODO UNDOCUMENTED
*
* @module bloom
* @class [bloom] bloom
*/
var utils = require("./utils.js");
/* eslint-disable no-bitwise */
function codePointToInt(codePoint) {
if (codePoint >= 48 && codePoint <= 57) { /*['0'..'9'] -> [0..9]*/
return codePoint-48;
}
Iif (codePoint >= 65 && codePoint <= 70) { /*['A'..'F'] -> [10..15]*/
return codePoint-55;
}
Eif (codePoint >= 97 && codePoint <= 102) { /*['a'..'f'] -> [10..15]*/
return codePoint-87;
}
throw "invalid bloom";
}
function testBytes(bloom, bytes) {
var hash = utils.sha3(bytes).replace('0x','');
for (var i = 0; i < 12; i += 4) {
// calculate bit position in bloom filter that must be active
var bitpos = ((parseInt(hash.substr(i, 2), 16) << 8) + parseInt(hash.substr((i+2), 2), 16)) & 2047;
var code = codePointToInt(bloom.charCodeAt(bloom.length - 1 - Math.floor(bitpos/4)));
var offset = 1 << (bitpos % 4);
if ((code&offset) !== offset) {
return false;
}
}
return true;
}
/**
* Returns true if address is part of the given bloom.
* note: false positives are possible.
*
* @method testAddress
* @param {String} hex encoded bloom
* @param {String} address in hex notation
* @returns {Boolean} topic is (probably) part of the block
*/
var testAddress = function(bloom, address) {
Iif (!utils.isBloom(bloom)) {
throw 'Invalid bloom given';
}
Iif (!utils.isAddress(address)) {
throw 'Invalid address given: "'+ address +'\"';
}
return testBytes(bloom, address);
};
/**
* Returns true if the topic is part of the given bloom.
* note: false positives are possible.
*
* @method hasTopic
* @param {String} hex encoded bloom
* @param {String} address in hex notation
* @returns {Boolean} topic is (probably) part of the block
*/
var testTopic = function(bloom, topic) {
Iif (!utils.isBloom(bloom)) throw "invalid bloom";
Iif (!utils.isTopic(topic)) throw "invalid topic";
return testBytes(bloom, topic);
};
module.exports = {
testAddress: testAddress,
testTopic: testTopic
};
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