node_modules/bn.js/README.md

bn.js

BigNum in pure javascript

Build Status

Install

npm install --save bn.js

Usage

const BN = require('bn.js');

var a = new BN('dead', 16);
var b = new BN('101010', 2);

var res = a.add(b);
console.log(res.toString(10));  // 57047

Note: decimals are not supported in this library.

Notation

Prefixes

There are several prefixes to instructions that affect the way the work. Here is the list of them in the order of appearance in the function name:

Postfixes

The only available postfix at the moment is:

Examples

Instructions

Prefixes/postfixes are put in parens at the of the line. endian - could be either le (little-endian) or be (big-endian).

Utilities

Arithmetics

Bit operations

Reduction

Fast reduction

When doing lots of reductions using the same modulo, it might be beneficial to use some tricks: like Montgomery multiplication, or using special algorithm for Mersenne Prime.

Reduction context

To enable this tricks one should create a reduction context:

var red = BN.red(num);

where num is just a BN instance.

Or:

var red = BN.red(primeName);

Where primeName is either of these Mersenne Primes:

Or:

var red = BN.mont(num);

To reduce numbers with Montgomery trick. .mont() is generally faster than .red(num), but slower than BN.red(primeName).

Converting numbers

Before performing anything in reduction context - numbers should be converted to it. Usually, this means that one should:

Here is how one may convert numbers to red:

var redA = a.toRed(red);

Where red is a reduction context created using instructions above

Here is how to convert them back:

var a = redA.fromRed();

Red instructions

Most of the instructions from the very start of this readme have their counterparts in red context:

LICENSE

This software is licensed under the MIT License.

Copyright Fedor Indutny, 2015.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.



thisisnic/starrating documentation built on May 18, 2019, 1:32 p.m.