bitcoinjs-lib/src/util.js
2013-12-01 22:27:13 -05:00

73 lines
2.0 KiB
JavaScript

var BigInteger = require('./jsbn/jsbn');
var Crypto = require('./crypto-js/crypto');
module.exports = {
/**
* Cross-browser compatibility version of Array.isArray.
*/
isArray: Array.isArray || function(o)
{
return Object.prototype.toString.call(o) === '[object Array]';
},
/**
* Create a byte array representing a number with the given length
*/
numToBytes: function(num,bytes) {
if (bytes === undefined) bytes = 8;
if (bytes == 0) return [];
else return [num % 256].concat(module.exports.numToBytes(Math.floor(num / 256),bytes-1));
},
/**
* Convert a byte array to the number that it represents
*/
bytesToNum: function(bytes) {
if (bytes.length == 0) return 0;
else return bytes[0] + 256 * module.exports.bytesToNum(bytes.slice(1));
},
/**
* Turn an integer into a "var_int".
*
* "var_int" is a variable length integer used by Bitcoin's binary format.
*
* Returns a byte array.
*/
numToVarInt: function(num) {
var m = module.exports;
if (num < 253) return [num];
else if (num < 65536) return [253].concat(m.numToBytes(num,2));
else if (num < 4294967296) return [254].concat(m.numToBytes(num,4));
else return [253].concat(m.numToBytes(num,8));
},
bytesToWords: function (bytes) {
var words = [];
for (var i = 0, b = 0; i < bytes.length; i++, b += 8) {
words[b >>> 5] |= bytes[i] << (24 - b % 32);
}
return words;
},
wordsToBytes: function (words) {
var bytes = [];
for (var b = 0; b < words.length * 32; b += 8) {
bytes.push((words[b >>> 5] >>> (24 - b % 32)) & 0xFF);
}
return bytes;
},
/**
* Calculate RIPEMD160(SHA256(data)).
*
* Takes an arbitrary byte array as inputs and returns the hash as a byte
* array.
*/
sha256ripe160: function (data) {
return Crypto.RIPEMD160(Crypto.SHA256(data, {asBytes: true}), {asBytes: true});
},
error: function(msg) {
throw new Error(msg);
}
};