64bit Long Integer on Buffer/ArrayBuffer in Pure JavaScript
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README.md

int64-buffer

64bit Long Integer on Buffer/Array/ArrayBuffer in Pure JavaScript

npm version Build Status Coverage Status

JavaScript's number based on IEEE-754 could only handle 53 bits precision. This module provides two pair of classes: Int64BE/Uint64BE and Int64LE/Uint64LE which could hold 64 bits long integer and loose no bit.

Features

  • Int64BE/Int64LE for signed integer, Uint64BE/Uint64LE for unsigned.
  • Int64BE/Uint64BE for big-endian, Uint64BE/Uint64LE for little-endian.
  • Buffer/Uint8Array/Array/Array-like storage of 8 bytes length with offset.
  • No mathematical methods provided, such as add(), sub(), mul(), div() etc.
  • Optimized only for 64 bits. If you need Int128, use bignum etc.
  • Small. 3KB when minified. No other module required. Portable pure JavaScript.
  • Tested on node.js v4, v6, v8, v10 and Web browsers.

Usage

Int64BE is the class to host a 64 bit signed long integer int64_t.

var Int64BE = require("int64-buffer").Int64BE;

var big = new Int64BE(-1);

console.log(big - 0); // -1

console.log(big.toBuffer()); // <Buffer ff ff ff ff ff ff ff ff>

It uses Buffer on Node.js and Uint8Array on modern Web browsers.

Uint64BE is the class to host a 64 bit unsigned positive long integer uint64_t.

var Uint64BE = require("int64-buffer").Uint64BE;

var big = new Uint64BE(Math.pow(2, 63)); // a big number with 64 bits

console.log(big - 0); // 9223372036854776000 = IEEE-754 loses last bits

console.log(big + ""); // "9223372036854775808" = perfectly correct

Int64LE and Uint64LE work as same as above but with little-endian storage.

Input Constructor

  • new Uint64BE(number)
var big = new Uint64BE(1234567890);
console.log(big - 0); // 1234567890
  • new Uint64BE(high, low)
var big = new Uint64BE(0x12345678, 0x9abcdef0);
console.log(big.toString(16)); // "123456789abcdef0"
  • new Uint64BE(string, radix)
var big = new Uint64BE("123456789abcdef0", 16);
console.log(big.toString(16)); // "123456789abcdef0"
  • new Uint64BE(buffer)
var buffer = Buffer.from([1,2,3,4,5,6,7,8]);
var big = new Uint64BE(buffer);
console.log(big.toString(16)); // "102030405060708"
  • new Uint64BE(uint8array)
var uint8array = new Uint8Array([1,2,3,4,5,6,7,8]);
var big = new Uint64BE(uint8array);
console.log(big.toString(16)); // "102030405060708"
  • new Uint64BE(arraybuffer)
var arraybuffer = (new Uint8Array([1,2,3,4,5,6,7,8])).buffer;
var big = new Uint64BE(arraybuffer);
console.log(big.toString(16)); // "102030405060708"
  • new Uint64BE(array)
var array = [1,2,3,4,5,6,7,8];
var big = new Uint64BE(array);
console.log(big.toString(16)); // "102030405060708"
  • new Uint64BE(buffer, offset)
var buffer = Buffer.from([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]);
var big = new Uint64BE(buffer, 8);
console.log(big.toString(16)); // "90a0b0c0d0e0f10"
  • new Uint64BE(buffer, offset, number)
var buffer = Buffer.from(16);
var big = new Uint64BE(buffer, 8, 0x1234567890);
console.log(big.toString(16)); // "1234567890"
console.log(buffer[15].toString(16)); // "90"
  • new Uint64BE(buffer, offset, high, low)
var buffer = new Uint8Array(16);
var big = new Uint64BE(buffer, 8, 0x12345678, 0x9abcdef0);
console.log(big.toString(16)); // "123456789abcdef0"
console.log(buffer[15].toString(16)); // "f0"
  • new Uint64BE(buffer, offset, string, radix)
var buffer = new Array(16);
var big = new Uint64BE(buffer, 8, "123456789abcdef0", 16);
console.log(big.toString(16)); // "123456789abcdef0"
console.log(buffer[15].toString(16)); // "f0"

Output Methods

  • valueOf()
var big = Uint64BE(1234567890);
console.log(big - 0); // 1234567890
  • toNumber()
var big = Uint64BE(1234567890);
console.log(big.toNumber()); // 1234567890
  • toString(radix)
var big = Uint64BE(0x1234567890);
console.log(big.toString()); // "78187493520"
console.log(big.toString(16)); // "1234567890"
  • toBuffer()
var big = Uint64BE([1,2,3,4,5,6,7,8]);
console.log(big.toBuffer()); // <Buffer 01 02 03 04 05 06 07 08>
  • toArrayBuffer()
var big = Uint64BE(0);
var buf = new Int8Array(big.toArrayBuffer());
console.log(buf); // Int8Array { '0': 1, '1': 2, '2': 3, '3': 4, '4': 5, '5': 6, '6': 7, '7': 8 }
  • toArray()
var big = Uint64BE([1,2,3,4,5,6,7,8]);
console.log(big.toArray()); // [ 1, 2, 3, 4, 5, 6, 7, 8 ]

Browsers Build

<meta http-equiv="X-UA-Compatible" content="IE=edge">
<script src="https://rawgit.com/kawanet/int64-buffer/master/dist/int64-buffer.min.js"></script>
<script>

  var i = Int64BE("1234567890123456789");
  console.log(i.toString(10)); // "1234567890123456789"
  
  var u = new Uint64BE([0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF]);
  console.log(u.toString(16)); // "123456789abcdef"

</script>

Installation

npm install int64-buffer --save

GitHub

The MIT License (MIT)

Copyright (c) 2015-2018 Yusuke Kawasaki

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.