Hawkynt

MS-LZH

Microsoft DriveSpace 3 codec: LZ77 over a 4 KiB window feeding a DEFLATE-shaped alphabet of 286 literal/length symbols and 30 distance symbols. Blocks carry a leading type bit selecting the fixed Huffman tables or per-block dynamic tables in the RFC 1951 dynamic-header layout.

Properties

Property Value
Category Compression Algorithms
Sub-category Hybrid
Security status Not classified
Complexity Advanced
Inventor Microsoft Corporation
Year 1995
Origin 🇺🇸 United States
Source algorithms/compression/ms-lzh.js

Security

Status: not classified — treat as unverified.

No vulnerabilities are recorded for this implementation.

Documentation

References

Test vectors

8 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — Empty input - header only

Field Value
input (empty)
expected 00000000

Vector 2 — Single byte ‘A’ - one literal then end-of-block

Field Value
input 41
expected 010000003880

Vector 3 — All literals (ABCD)

Field Value
input 41424344
expected 0400000038b939ba00

Vector 4 — Simple repetition - AAAA

Field Value
input 41414141
expected 0400000038810000

Vector 5 — Pattern ABCABC

Field Value
input 414243414243
expected 0600000038b939811000

Vector 6 — English text with repeats

Field Value
input 74686520717569636b2062726f776e20 666f78206a756d7073206f7665722074 6865206c617a7920646f672e20746865 20717569636b2062726f776e20666f78 206a756d7073206f7665722074686520 6c617a7920646f672e20
expected 5a000000524c4aa850d2ccc9cda84951 4fd3cf284b4fd4284d52ced051a84fd3 4ad128024e9c91aaa950949f975e0674 8e5600

Vector 7 — Long run - 256 bytes of ‘a’ (match length capped at 64)

Field Value
input 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161
expected 0001000048e2831418a0290000

Vector 8 — All 256 byte values in order

Field Value
input 000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f 404142434445464748494a4b4c4d4e4f 505152535455565758595a5b5c5d5e5f 606162636465666768696a6b6c6d6e6f 707172737475767778797a7b7c7d7e7f 808182838485868788898a8b8c8d8e8f 909192939495969798999a9b9c9d9e9f a0a1a2a3a4a5a6a7a8a9aaabacadaeaf b0b1b2b3b4b5b6b7b8b9babbbcbdbebf c0c1c2c3c4c5c6c7c8c9cacbcccdcecf d0d1d2d3d4d5d6d7d8d9dadbdcdddedf e0e1e2e3e4e5e6e7e8e9eaebecedeeef f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
expected 00010000181899199a1a9b1b9c1c9d1d 9e1e9f1fa020a121a222a323a424a525 a626a727a828a929aa2aab2bac2cad2d ae2eaf2fb030b131b232b333b434b535 … (275 bytes; the full value is in the source)

← All algorithms

This site is open source. Improve this page.