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CRC Utils. Combines two or more CRC32 checksums into new one.

Package Exports

  • crc-utils2

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 (crc-utils2) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Node CRC32 Utils

Combines two or more CRC32 checksums into new one.

##How to build/install:

node-gyp configure build

or

npm install crc-utils

##Example:

var crcUtils = require('crc-utils');

// for crc32 checksum use lib: https://github.com/brianloveswords/buffer-crc32/
var crc32 = require('buffer-crc32');

var foo = new Buffer('foo');
var bar = new Buffer('bar');

var fooCrc32 = crc32(foo); // <Buffer 8c 73 65 21>
var barCrc32 = crc32(bar); // <Buffer 76 ff 8c aa>
 
var foobar = new Buffer('foobar');
var foobarCrc32 = crc32(foobar);

var foobarCrc32Combined = crcUtils.crc32_combine(
  fooCrc32.readUInt32BE(0), 
  barCrc32.readUInt32BE(0), 
  bar.length
); 

// CRC32 are the same but Endianness is prepared for GZIP format
console.log(foobarCrc32);         // <Buffer 9e f6 1f 95>
console.log(foobarCrc32Combined); // <Buffer 95 1f f6 9e>