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buffer-crc32

A pure javascript CRC32 algorithm that plays nice with binary data

buffer-crc32

Build Status

crc32 that works with binary data and fancy character sets, outputs buffer, signed or unsigned data and has tests.

Derived from the sample CRC implementation in the PNG specification: http://www.w3.org/TR/PNG/#D-CRCAppendix

install

npm install buffer-crc32

example

var crc32 = require('buffer-crc32');
// works with buffers 
var buf = Buffer([0x00, 0x73, 0x75, 0x70, 0x20, 0x62, 0x72, 0x6f, 0x00])
crc32(buf) // -> <Buffer 94 5a ab 4a> 
 
// has convenience methods for getting signed or unsigned ints 
crc32.signed(buf) // -> -1805997238 
crc32.unsigned(buf) // -> 2488970058 
 
// will cast to buffer if given a string, so you can 
// directly use foreign characters safely 
crc32('自動販売機') // -> <Buffer cb 03 1a c5> 
 
// and works in append mode too 
var partialCrc = crc32('hey');
var partialCrc = crc32(' ', partialCrc);
var partialCrc = crc32('sup', partialCrc);
var partialCrc = crc32(' ', partialCrc);
var finalCrc = crc32('bros', partialCrc); // -> <Buffer 47 fa 55 70> 

tests

This was tested against the output of zlib's crc32 method. You can run the tests withnpm test (requires tap)

see also

https://github.com/alexgorbatchev/node-crc, crc.buffer.crc32 also supports buffer inputs and return unsigned ints (thanks @tjholowaychuk).

license

MIT/X11