Package Exports

node-crc

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (node-crc) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

CRC For Node.js

Introduction

This module can compute different types of CRC checksum by using N-API.

NOTICE: N-API is a new experimental feature in Node.js 8.

Installation

Run npm i or npm install to install.

npm install node-crc

If you want to save this module to package.json, please add --save option.

npm install node-crc --save

Initialization

Import this module by using require function.

const crc = require('node-crc');

Usage

You can use crc function to compute a CRC value by providing the length of bits, expression, reflection, an initial value and a final xor value. For example, if you want to compute a CRC-24 value.

var result = crc.crc(24, false, 0x00864cfb, 0x00000000, 0x00b704ce, 0x00000000, 0x00000000, 0x00000000, Buffer.from('hello', 'utf8')).toString('hex');
// Arguments: the length of bits, reflection, low bits of expression, high bits of expression, low bits of the initial value, high bits of the initial value, low bits of the final xor value, high bits of the final xor value, the source data buffer

To simplify the usage, there are several common versions of CRC whose computing functions are already built-in.

crc8(crc8atm)
crc8cdma
crc16(crc16ibm)
crc16ccitt(crcccitt)
crc32(crc32ieee, also called crc32b in mhash)
crc32mhash
- mhash is a common library which has two weird versions of CRC32 called crc32 and crc32b. crc32 and crc32mhash in this module are crc32b and crc32 in mhash respectively.
crc32c
crc64(crc64ecma)
crc64iso

Input data and output data are buffers.

For instance,

var result = crc.crc32(Buffer.from('hello', 'utf8')).toString('hex');
var result2 = crc.crc64(Buffer.from('world', 'utf8')).toString('hex');

Tests

To run the test suite, first install the dependencies, then run npm test:

npm install
npm test

Benchmark

To run the benchmark suite, first install the dependencies, then run npm run benchmark:

npm install
npm run benchmark

Here is my result,

CRC-8
  - 76 milliseconds
  - Result HEX: 60
  ✓ another crc module (77ms)
  - 67 milliseconds
  - Result HEX: 60
  ✓ this module (67ms)

CRC-16
  - 84 milliseconds
  - Result HEX: 94bc
  ✓ another crc module (84ms)
  - 70 milliseconds
  - Result HEX: 94bc
  ✓ this module (70ms)

CRC-32
  - 122 milliseconds
  - Result HEX: ab526987
  ✓ another crc module (122ms)
  - 68 milliseconds
  - Result HEX: ab526987
  ✓ this module (68ms)

CRC-64
  - I cannot compute CRC-64!
  ✓ another crc module
  - 74 milliseconds
  - Result HEX: aa9d25ffe7f7c6fd
  ✓ this module (74ms)

License

MIT