Source: mining/mine.js

  1. /*!
  2.  * mine.js - mining function for bcoin
  3.  * Copyright (c) 2014-2017, Christopher Jeffrey (MIT License).
  4.  * https://github.com/bcoin-org/bcoin
  5.  */
  7. 'use strict';
  9. const assert = require('bsert');
  10. const hash256 = require('bcrypto/lib/hash256');
  12. /**
  13.  * Hash until the nonce overflows.
  14.  * @alias module:mining.mine
  15.  * @param {Buffer} data
  16.  * @param {Buffer} target - Big endian.
  17.  * @param {Number} min
  18.  * @param {Number} max
  19.  * @returns {Number} Nonce or -1.
  20.  */
  22. function mine(data, target, min, max) {
  23.   let nonce = min;
  25.   data.writeUInt32LE(nonce, 76, true);
  27.   // The heart and soul of the miner: match the target.
  28.   while (nonce <= max) {
  29.     // Hash and test against the next target.
  30.     if (rcmp(hash256.digest(data), target) <= 0)
  31.       return nonce;
  33.     // Increment the nonce to get a different hash.
  34.     nonce += 1;
  36.     // Update the raw buffer.
  37.     data.writeUInt32LE(nonce, 76, true);
  38.   }
  40.   return -1;
  41. }
  43. /**
  44.  * "Reverse" comparison so we don't have
  45.  * to waste time reversing the block hash.
  46.  * @ignore
  47.  * @param {Buffer} a
  48.  * @param {Buffer} b
  49.  * @returns {Number}
  50.  */
  52. function rcmp(a, b) {
  53.   assert(a.length === b.length);
  55.   for (let i = a.length - 1; i >= 0; i--) {
  56.     if (a[i] < b[i])
  57.       return -1;
  58.     if (a[i] > b[i])
  59.       return 1;
  60.   }
  62.   return 0;
  63. }
  65. /*
  66.  * Expose
  67.  */
  69. module.exports = mine;