Binary run-length encoding packer w/ flexible repeat bit widths
npm install @thi.ng/rle-pack
!npm downloads
> [!NOTE]
> This is one of 214 standalone projects, maintained as part
> of the @thi.ng/umbrella monorepo
> and anti-framework.
>
> 🚀 Please help me to work full-time on these projects by sponsoring me on
> GitHub. Thank you! ❤️
- About
- Encoding format
- Status
- Related packages
- Installation
- Dependencies
- API
- Authors
- License
Binary run-length
encoding
packer/unpacker with support for customizable input word sizes (1 - 32
bits) and repeat count (run-length) bit sizes (1 - 16 bits). The encoder
uses 4 different repeat group sizes (thresholds) to minimize the number
of bits used to store the run lengths. The range of supported run
lengths is 16 bits (i.e. 65536 repetitions). If a value is repeated more
often than that, the remainder will be encoded using additional RLE
chunks...
- 32 bits - original number of words
- 5 bits - word size
- 16 bits - 4x RLE repeat group / chunk sizes (in bits)
The default group sizes are: 3, 4, 8, 16, i.e. 8, 16, 256, 65536 repetitions
Then per value:
- 1 bit - encoding flag (1 = RLE encoded, 0 = single occurrence)
- 2 bits - repeat or chunk class ID
- m bits - repeat count or chunk size (if greater than max group size
then split into chunks...)
- n bits - value(s)
STABLE - used in production
Search or submit any issues for this package
- @thi.ng/binary - 100+ assorted binary / bitwise operations, conversions, utilities, lookup tables
- @thi.ng/bitstream - ES6 iterator based read/write bit streams with support for variable word widths
- @thi.ng/range-coder - Binary data range encoder / decoder
``bash`
yarn add @thi.ng/rle-pack
ESM import:
`ts`
import * as rle from "@thi.ng/rle-pack";
Browser ESM import:
`html`
For Node.js REPL:
`js`
const rle = await import("@thi.ng/rle-pack");
Package sizes (brotli'd, pre-treeshake): ESM: 636 bytes
- @thi.ng/bitstream
- @thi.ng/errors
`ts
import { encode, decode } from "@thi.ng/rle-pack";
// prepare dummy data
src = new Uint8Array(1024);
src.set([1,1,1,1,1,2,2,2,2,3,3,3,4,4,5,4,4,3,3,3,2,2,2,2,1,1,1,1,1], 512);
// pack data
packed = encode(src, src.length);
packed.length
// 30 => 2.93% of original
// pack with custom word size (3 bits, i.e. our value range is only 0-7)
// and use custom repeat group sizes suitable for our data
alt = encode(src, src.length, 3, [1, 2, 3, 9]);
alt.length
// 20 => 1.95% of original, 66% of default config
// unpack
unpacked = new Uint8Array(decode(alt));
`
If this project contributes to an academic publication, please cite it as:
`bibtex``
@misc{thing-rle-pack,
title = "@thi.ng/rle-pack",
author = "Karsten Schmidt",
note = "https://thi.ng/rle-pack",
year = 2017
}
© 2017 - 2026 Karsten Schmidt // Apache License 2.0