| 1 | /*jshint bitwise: false*/
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| 2 |
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| 3 | /*
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| 4 | This file is part of web3.js.
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| 5 |
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| 6 | web3.js is free software: you can redistribute it and/or modify
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| 7 | it under the terms of the GNU Lesser General Public License as published by
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| 8 | the Free Software Foundation, either version 3 of the License, or
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| 9 | (at your option) any later version.
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| 10 |
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| 11 | web3.js is distributed in the hope that it will be useful,
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | GNU Lesser General Public License for more details.
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| 15 |
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| 16 | You should have received a copy of the GNU Lesser General Public License
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| 17 | along with web3.js. If not, see <http://www.gnu.org/licenses/>.
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| 18 | */
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| 19 |
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| 20 | /**
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| 21 | * @file bloom.js
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| 22 | * @author Bas van Kervel <bas@ethereum.org>
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| 23 | * @date 2017
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| 24 | */
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| 25 |
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| 26 | /**
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| 27 | * Ethereum bloom filter support.
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| 28 | *
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| 29 | * TODO UNDOCUMENTED
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| 30 | *
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| 31 | * @module bloom
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| 32 | * @class [bloom] bloom
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| 33 | */
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| 34 |
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| 35 | var utils = require("./utils.js");
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| 36 |
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| 37 | function codePointToInt(codePoint) {
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| 38 | if (codePoint >= 48 && codePoint <= 57) { /*['0'..'9'] -> [0..9]*/
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| 39 | return codePoint-48;
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| 40 | }
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| 41 |
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| 42 | if (codePoint >= 65 && codePoint <= 70) { /*['A'..'F'] -> [10..15]*/
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| 43 | return codePoint-55;
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| 44 | }
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| 45 |
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| 46 | if (codePoint >= 97 && codePoint <= 102) { /*['a'..'f'] -> [10..15]*/
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| 47 | return codePoint-87;
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| 48 | }
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| 49 |
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| 50 | throw "invalid bloom";
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| 51 | }
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| 52 |
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| 53 | function testBytes(bloom, bytes) {
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| 54 | var hash = utils.sha3(bytes).replace('0x','');
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| 55 |
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| 56 | for (var i = 0; i < 12; i += 4) {
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| 57 | // calculate bit position in bloom filter that must be active
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| 58 | var bitpos = ((parseInt(hash.substr(i, 2), 16) << 8) + parseInt(hash.substr((i+2), 2), 16)) & 2047;
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| 59 |
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| 60 | // test if bitpos in bloom is active
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| 61 | var code = codePointToInt(bloom.charCodeAt(bloom.length - 1 - Math.floor(bitpos/4)));
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| 62 | var offset = 1 << (bitpos % 4);
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| 63 |
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| 64 | if ((code&offset) !== offset) {
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| 65 | return false;
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| 66 | }
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| 67 | }
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| 68 |
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| 69 | return true;
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| 70 | }
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| 71 |
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| 72 | /**
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| 73 | * Returns true if address is part of the given bloom.
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| 74 | * note: false positives are possible.
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| 75 | *
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| 76 | * @method testAddress
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| 77 | * @param {String} hex encoded bloom
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| 78 | * @param {String} address in hex notation
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| 79 | * @returns {Boolean} topic is (probably) part of the block
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| 80 | */
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| 81 | var testAddress = function(bloom, address) {
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| 82 | if (!utils.isBloom(bloom)) {
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| 83 | throw 'Invalid bloom given';
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| 84 | }
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| 85 | if (!utils.isAddress(address)) {
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| 86 | throw 'Invalid address given: "'+ address +'\"';
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| 87 | }
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| 88 |
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| 89 | return testBytes(bloom, address);
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| 90 | };
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| 91 |
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| 92 | /**
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| 93 | * Returns true if the topic is part of the given bloom.
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| 94 | * note: false positives are possible.
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| 95 | *
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| 96 | * @method hasTopic
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| 97 | * @param {String} hex encoded bloom
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| 98 | * @param {String} address in hex notation
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| 99 | * @returns {Boolean} topic is (probably) part of the block
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| 100 | */
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| 101 | var testTopic = function(bloom, topic) {
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| 102 | if (!utils.isBloom(bloom)) throw "invalid bloom";
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| 103 | if (!utils.isTopic(topic)) throw "invalid topic";
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| 104 |
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| 105 | return testBytes(bloom, topic);
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| 106 | };
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| 107 |
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| 108 | module.exports = {
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| 109 | testAddress: testAddress,
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| 110 | testTopic: testTopic
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| 111 | };
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