https://github.com/limium/libans

Java implementation of ANS
https://github.com/limium/libans

ans asymmetric-numeral-systems java library

Last synced: 15 days ago
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Java implementation of ANS

• Host: GitHub
• URL: https://github.com/limium/libans
• Owner: LiMium
• License: lgpl-3.0
• Created: 2018-02-03T15:53:18.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2018-02-06T18:54:08.000Z (almost 7 years ago)
• Last Synced: 2024-11-05T12:22:16.744Z (2 months ago)
• Topics: ans, asymmetric-numeral-systems, java, library
• Language: Java
• Size: 19.5 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# lib ANS

A pure Java implementation of

[ANS](https://en.wikipedia.org/wiki/Asymmetric_Numeral_Systems). Currently,

only the rANS variant has been implemented.

ANS has time performance similar to Huffman coding, but its compression is as

efficient as Arithmetic coding. However, ANS requires more memory (O(N)) as

symbols need to be buffered and encoded in reverse order of their appearance.

The encoded stream also needs to be reversed, requiring temporary storage, but

that should not take up a lot of space (due to compression).

# Design

This library uses an abstract Symbol Statistics interface, thus providing full

cusomtization. Some example Statistical implementations are in the tests.

# Status

The current focus is on stability. The code has been well tested (see test/),

but consider it beta quality as of now.

Future ideas:

  * Use a dynamically growing stack

  * (optimisation) : Avoid division in encoder by using "reciprocals", ala Alverson

# License

LGPL3 (See LICENSE.txt)

# Credits

* Jarek Duda who invented ANS

* Code inspiration from https://github.com/rygorous/ryg_rans