js-crc32/README.md

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# crc32
Standard CRC-32 algorithm implementation in JS (for the browser and nodejs).
Emphasis on correctness and performance.
## Installation
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With [npm](https://www.npmjs.org/package/crc-32):
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$ npm install crc-32
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In the browser:
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<script src="crc32.js"></script>
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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`
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## Usage
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In all cases, the relevant function takes a single argument representing data.
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The return value is a signed 32-bit integer.
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- `CRC32.buf(byte array or buffer)` assumes the argument is a set of 8-bit
unsigned integers (e.g. nodejs `Buffer` or simple array of ints).
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- `CRC32.bstr(binary string)` interprets the argument as a binary string where
the `i`-th byte is the low byte of the UCS-2 char: `str.charCodeAt(i) & 0xFF`
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- `CRC32.str(string)` interprets the argument as a standard JS string
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For example:
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```js
> // 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
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> [CRC32.str("\u2603"), CRC32.str("\u0003")] // [ -1743909036, 1259060791 ]
> [CRC32.bstr("\u2603"), CRC32.bstr("\u0003")] // [ 1259060791, 1259060791 ]
> [CRC32.buf([0x2603]), CRC32.buf([0x0003])] // [ 1259060791, 1259060791 ]
```
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## Testing
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`make test` will run the node-based tests.
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To run the in-browser tests, run a local server and go to the `ctest` directory.
To update the browser artifacts, run `make ctest`.
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`make baseline` will generate baseline files based on the unicode mapping at
<http://mathias.html5.org>
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## 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.
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## Badges
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[![Build Status](https://travis-ci.org/SheetJS/js-crc32.svg?branch=master)](https://travis-ci.org/SheetJS/js-crc32)
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[![Coverage Status](http://img.shields.io/coveralls/SheetJS/js-crc32/master.svg)](https://coveralls.io/r/SheetJS/js-crc32?branch=master)
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[![Analytics](https://ga-beacon.appspot.com/UA-36810333-1/SheetJS/js-crc32?pixel)](https://github.com/SheetJS/js-crc32)