WZIP and WLZ4: LZ77 Codecs with Match-Length-Dependent Sliding Windows
Abstract
An LZ77 codec bounds every match by one sliding window, trading cheap offsets for short matches against reach for long ones. Match-length-dependent windows refine this trade-off: each match length has its own window, and the decoder infers the offset range from the decoded length. We present two such codecs: WLZ4, a byte-aligned LZ4-class format with one-byte and flagged offsets, and WZIP, an entropy-coded Zstandard-class format. Each block begins with its decoded length, from which WZIP derives its widest window and a decoder sizes its output. LZ4 blocks may expand incompressible input by 0.4%; WLZ4 adds at most 15 bytes, WZIP 2. We describe the formats, threaded match finders, decoders and parser. On Silesia, WLZ4 reaches a ratio up to 16% above LZ4HC's, decoding more slowly, and WZIP exceeds Zstandard 22's ratio while its trusted decoder runs at 91% of Zstandard's speed (87% checked; on enwik9, about as fast).
Related
- Lempel-Ziv Parsing with Match-Length-Dependent Windows: Universality and Limits
- KAYROS: An Anytime and Exact Solver for the Time-Dependent Vehicle Routing Problem with Time Windows - Extended Version
- Match forecasts in UEFA club competitions: Elo ratings versus Transfermarkt valuations
- The Big Match under translation-invariant charges
- A Decision-Theoretic Framework for Comparing Likelihood Ratio Methods for the Rare Type Match Problem
BibTeX
@misc{wu2026wzip,
title = {{WZIP and WLZ4: LZ77 Codecs with Match-Length-Dependent Sliding Windows}},
author = {Yingquan "Cody" Wu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.14079},
eprint = {2610.14079},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.14079},
}
RIS
TY - UNPB
TI - WZIP and WLZ4: LZ77 Codecs with Match-Length-Dependent Sliding Windows
AU - Yingquan "Cody" Wu
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.14079
UR - https://arxiv.org/abs/2610.14079
AB - An LZ77 codec bounds every match by one sliding window, trading cheap offsets for short matches against reach for long ones. Match-length-dependent windows refine this trade-off: each match length has its own window, and the decoder infers the offset range from the decoded length. We present two such codecs: WLZ4, a byte-aligned LZ4-class format with one-byte and flagged offsets, and WZIP, an entropy-coded Zstandard-class format. Each block begins with its decoded length, from which WZIP derives its widest window and a decoder sizes its output. LZ4 blocks may expand incompressible input by 0.4%; WLZ4 adds at most 15 bytes, WZIP 2. We describe the formats, threaded match finders, decoders and parser. On Silesia, WLZ4 reaches a ratio up to 16% above LZ4HC's, decoding more slowly, and WZIP exceeds Zstandard 22's ratio while its trusted decoder runs at 91% of Zstandard's speed (87% checked; on enwik9, about as fast).
ER -