Minimal LZ77-based compression with a deliberately tiny decoder. Literals pass through untouched; the escape byte 0xFF introduces either an escaped literal or a back-reference over a 2 KiB window. Designed for embedded systems that need fast decompression with minimal memory.
| Property | Value |
|---|---|
| Category | Compression Algorithms |
| Sub-category | Dictionary |
| Security status | Not classified |
| Complexity | Intermediate |
| Inventor | Marcus Geelnard |
| Year | 2004 |
| Origin | 🇸🇪 Sweden |
| Source | algorithms/compression/lzg.js |
Status: not classified — treat as unverified.
No vulnerabilities are recorded for this implementation.
9 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
| Field | Value |
|---|---|
input |
41 |
expected |
0100000041 |
Vector 3 — All literals - no match of length 3 exists (ABCD)
| Field | Value |
|---|---|
input |
41424344 |
expected |
0400000041424344 |
Vector 4 — Simple repetition - AAAA (literal plus 3-byte back-reference at distance 1)
| Field | Value |
|---|---|
input |
41414141 |
expected |
0400000041ff010001 |
Vector 5 — Pattern ABCABC - 3 literals plus a back-reference at distance 3
| Field | Value |
|---|---|
input |
414243414243 |
expected |
06000000414243ff010003 |
Vector 6 — Escaped literal - the escape byte 0xFF appearing in the data
| Field | Value |
|---|---|
input |
ff41ff |
expected |
03000000ff0041ff00 |
Vector 7 — Long run - 256 bytes of ‘a’ (match length capped at 257, then 255)
| Field | Value |
|---|---|
input |
61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 61616161616161616161616161616161 |
expected |
0001000061fffd0001 |
Vector 8 — Alternating pattern - 200x ‘ab’
| Field | Value |
|---|---|
input |
61626162616261626162616261626162 61626162616261626162616261626162 61626162616261626162616261626162 61626162616261626162616261626162 … (400 bytes; the full value is in the source) |
expected |
900100006162ffff0002ff8b0002 |
Vector 9 — Binary sample - all 256 byte values in order (no repeats)
| Field | Value |
|---|---|
input |
000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f 404142434445464748494a4b4c4d4e4f 505152535455565758595a5b5c5d5e5f 606162636465666768696a6b6c6d6e6f 707172737475767778797a7b7c7d7e7f 808182838485868788898a8b8c8d8e8f 909192939495969798999a9b9c9d9e9f a0a1a2a3a4a5a6a7a8a9aaabacadaeaf b0b1b2b3b4b5b6b7b8b9babbbcbdbebf c0c1c2c3c4c5c6c7c8c9cacbcccdcecf d0d1d2d3d4d5d6d7d8d9dadbdcdddedf e0e1e2e3e4e5e6e7e8e9eaebecedeeef f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff |
expected |
00010000000102030405060708090a0b 0c0d0e0f101112131415161718191a1b 1c1d1e1f202122232425262728292a2b 2c2d2e2f303132333435363738393a3b … (261 bytes; the full value is in the source) |