LZ48/LZ49: Difference between revisions
first draft |
m pres |
||
| Line 2: | Line 2: | ||
Basically limitations are removed | Basically limitations are removed | ||
* no need to have 4 bytes literal values at the beginning | |||
* no need to have 4 bytes literal values at the end | |||
* compression is optimal as the key search do not use a hash table | |||
Offset changes from 16 bits to 8 bits for LZ48 and 9 bits for LZ49 | Offset changes from 16 bits to 8 bits for LZ48 and 9 bits for LZ49. | ||
The compression is good (not as good as ZX7 or Exomizer) but the decompression speed is very fast | The compression is good (not as good as ZX7 or Exomizer) but the decompression speed is very fast. | ||
As there is no header, the cruncher is suitable to crunch a big amount of small data areas | As there is no header, the cruncher is suitable to crunch a big amount of small data areas. | ||
Z80 assembly cruncher, Z80 assembly decruncher and C sources may be found in the | |||
Official cpcwiki topic [http://www.cpcwiki.eu/forum/programming/lz48-cruncherdecruncher/ here] | Official cpcwiki topic [http://www.cpcwiki.eu/forum/programming/lz48-cruncherdecruncher/ here] | ||
Revision as of 07:47, 12 December 2017
LZ48 and LZ49 are derivated from LZ4 crunch/decrunch format, originally created by Yann Collet
Basically limitations are removed
- no need to have 4 bytes literal values at the beginning
- no need to have 4 bytes literal values at the end
- compression is optimal as the key search do not use a hash table
Offset changes from 16 bits to 8 bits for LZ48 and 9 bits for LZ49.
The compression is good (not as good as ZX7 or Exomizer) but the decompression speed is very fast.
As there is no header, the cruncher is suitable to crunch a big amount of small data areas.
Z80 assembly cruncher, Z80 assembly decruncher and C sources may be found in the
Official cpcwiki topic here