2.2 KiB
crc32
Standard CRC-32 algorithm implementation in JS (for the browser and nodejs). Emphasis on correctness and performance.
Installation
With npm:
$ npm install crc-32
In the browser:
<script src="crc32.js"></script>
The script will manipulate module.exports
if available (e.g. in a CommonJS
require
context). This is not always desirable. To prevent the behavior,
define DO_NOT_EXPORT_CRC
Usage
In all cases, the relevant function takes a single argument representing data.
The return value is a signed 32-bit integer.
-
CRC32.buf(byte array or buffer)
assumes the argument is a set of 8-bit unsigned integers (e.g. nodejsBuffer
or simple array of ints). -
CRC32.bstr(binary string)
interprets the argument as a binary string where thei
-th byte is the low byte of the UCS-2 char:str.charCodeAt(i) & 0xFF
-
CRC32.str(string)
interprets the argument as a standard JS string
For example:
> // var CRC32 = require('crc-32'); // uncomment this line if in node
> CRC32.str("SheetJS") // -1647298270
> CRC32.bstr("SheetJS") // -1647298270
> CRC32.buf([ 83, 104, 101, 101, 116, 74, 83 ]) // -1647298270
> [CRC32.str("\u2603"), CRC32.str("\u0003")] // [ -1743909036, 1259060791 ]
> [CRC32.bstr("\u2603"), CRC32.bstr("\u0003")] // [ 1259060791, 1259060791 ]
> [CRC32.buf([0x2603]), CRC32.buf([0x0003])] // [ 1259060791, 1259060791 ]
Testing
make test
will run the node-based tests.
To run the in-browser tests, run a local server and go to the ctest
directory.
To update the browser artifacts, run make ctest
.
License
Please consult the attached LICENSE file for details. All rights not explicitly granted by the Apache 2.0 license are reserved by the Original Author.