bitmessage-js/lib/worker.browser.js
2015-01-10 16:00:08 +03:00

54 lines
1.2 KiB
JavaScript

/**
* Web Worker routines for Browser platform.
*/
"use strict";
var Sha512 = require("sha.js/sha512");
function sha512(buf) {
return new Sha512().update(buf).digest();
}
function pow(opts) {
var nonce = opts.num;
var poolSize = opts.poolSize;
var message = new Buffer(72);
message.fill(0);
Buffer(opts.initialHash).copy(message, 8);
var targetHi = Math.floor(opts.target / 4294967296);
var targetLo = opts.target % 4294967296;
var digest, trialHi, trialLo;
while (true) {
// uint32_t overflow. There is no much need to fix it since 4G
// double hashes would we computed too long anyway in a Browser.
if (nonce > 4294967295) {
return -1;
}
message.writeUInt32BE(nonce, 4, true);
digest = sha512(sha512(message));
trialHi = digest.readUInt32BE(0, true);
if (trialHi > targetHi) {
nonce += poolSize;
} else if (trialHi === targetHi) {
trialLo = digest.readUInt32BE(4, true);
if (trialLo > targetLo) {
nonce += poolSize;
} else {
return nonce;
}
} else {
return nonce;
}
}
}
module.exports = function(self) {
self.onmessage = function(e) {
self.postMessage(pow(e.data));
};
};