bitmessage-js/lib/platform.js

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/**
* Node.js implementation of platform-specific routines.
*/
"use strict";
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var os = require("os");
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var crypto = require("crypto");
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var promise = typeof Promise === "undefined" ?
require("es6-promise").Promise :
Promise;
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var bignum = require("bignum");
var assert = require("./util").assert;
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var worker = require("./worker");
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var createHash = crypto.createHash;
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exports.sha512 = function(buf) {
return createHash("sha512").update(buf).digest();
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};
exports.sha256 = function(buf) {
return createHash("sha256").update(buf).digest();
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};
exports.ripemd160 = function(buf) {
return createHash("ripemd160").update(buf).digest();
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};
exports.randomBytes = crypto.randomBytes;
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// 2^64.
var B64 = bignum("18446744073709551616");
// NOTE(Kagami): We can't calculate entire target in JavaScript but the
// result can be represented in native number type without losing
// precision (targets mainly much less than 2^53).
exports.getTarget = function(opts) {
// Calculate it bottom-up, right-to-left.
var length = bignum(opts.payloadLength)
// To account for the nonce which we will append later.
.add(8)
.add(opts.payloadLengthExtraBytes);
var denominator = bignum(opts.ttl)
.mul(length)
.div(65536)
.add(length)
.mul(opts.nonceTrialsPerByte);
var target = B64.div(denominator).toNumber();
assert(target <= 9007199254740991, "Unsafe target");
return target;
};
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exports.pow = function(opts) {
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var poolSize = opts.poolSize || os.cpus().length;
// Check all input params prematurely to not let promise executor or
// worker to fail because of it.
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assert(typeof poolSize === "number", "Bad pool size");
assert(poolSize >= 1, "Pool size is too low");
assert(poolSize <= 1024, "Pool size is too high");
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assert(typeof opts.target === "number", "Bad target");
assert(opts.target >= 0, "Target is too low");
assert(opts.target <= 9007199254740991, "Target is too high");
assert(Buffer.isBuffer(opts.initialHash), "Bad initial hash");
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assert(opts.initialHash.length === 64, "Bad initial hash");
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// TODO(Kagami): Allow to cancel a POW (see `platform.browser.js`).
return new promise(function(resolve, reject) {
worker.powAsync(
poolSize,
opts.target,
opts.initialHash,
function(err, nonce) {
if (err) {
reject(err);
} else {
resolve(nonce);
}
}
);
});
};