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48 lines
1.4 KiB
48 lines
1.4 KiB
# buffer-crc32
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[](http://travis-ci.org/brianloveswords/buffer-crc32)
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crc32 that works with binary data and fancy character sets, outputs
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buffer, signed or unsigned data and has tests.
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Derived from the sample CRC implementation in the PNG specification: http://www.w3.org/TR/PNG/#D-CRCAppendix
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# install
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```
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npm install buffer-crc32
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```
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# example
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```js
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var crc32 = require('buffer-crc32');
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// works with buffers
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var buf = Buffer([0x00, 0x73, 0x75, 0x70, 0x20, 0x62, 0x72, 0x6f, 0x00])
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crc32(buf) // -> <Buffer 94 5a ab 4a>
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// has convenience methods for getting signed or unsigned ints
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crc32.signed(buf) // -> -1805997238
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crc32.unsigned(buf) // -> 2488970058
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// will cast to buffer if given a string, so you can
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// directly use foreign characters safely
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crc32('自動販売機') // -> <Buffer cb 03 1a c5>
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// and works in append mode too
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var partialCrc = crc32('hey');
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var partialCrc = crc32(' ', partialCrc);
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var partialCrc = crc32('sup', partialCrc);
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var partialCrc = crc32(' ', partialCrc);
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var finalCrc = crc32('bros', partialCrc); // -> <Buffer 47 fa 55 70>
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```
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# tests
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This was tested against the output of zlib's crc32 method. You can run
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the tests with`npm test` (requires tap)
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# see also
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https://github.com/alexgorbatchev/node-crc, `crc.buffer.crc32` also
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supports buffer inputs and return unsigned ints (thanks @tjholowaychuk).
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# license
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MIT/X11
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