SheetJS
c79a8fb6c9
- used Int32Array for storing CRC32 table when possible - buf/array impl 4-step unrolling - integration performance tests |
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| bits | ||
| ctest | ||
| misc | ||
| perf | ||
| .gitignore | ||
| .jscs.json | ||
| .travis.yml | ||
| crc32.js | ||
| LICENSE | ||
| Makefile | ||
| package.json | ||
| perf.txt | ||
| README.md | ||
| test.js | ||
crc32
Standard CRC-32 algorithm implementation in JS (for the browser and nodejs). Emphasis on correctness and performance.
Installation
In nodejs:
npm install crc-32
In the browser:
<script lang="javascript" src="crc32.js"></script>
The browser exposes a variable CRC32
Usage
-
CRC32.buf(byte array or buffer)assumes the argument is a set of 8 bit unsigned integers (e.g. nodejsBufferor simple array of ints) -
CRC32.bstr(binary string)interprets the argument as a binary string where thei-th byte isstr.charCodeAt(i) -
CRC32.str(string)interprets the argument as a standard JS string
Testing
make test will run the nodejs-based test. To run the in-browser tests, run a
local server and go to the ctest directory. To update the browser artifacts,
run make ctest.
Performance
make perf will run algorithmic performance tests (which should justify certain
decisions in the code).
make perf-all compares the performance of various crc-32 algorithms that
implement the correct form (note that the SSE intrinsic is designed for the
CRC32C checksum and uses a different polynomial).
Unexpected code patterns were based on performance testing in node and browser:
In the future ...
-
Specifying an arbitrary initial CRC value
-
Supporting different polynomials (e.g. CRC32C)
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.
