Portability | non-portable (type families) |
---|---|
Stability | experimental |
Maintainer | ekmett@gmail.com |
Compression algorithms are all about exploiting redundancy. When applying
an expensive Reducer
to a redundant source, it may be better to
extract the structural redundancy that is present. LZ78
is a compression
algorithm that does so, without requiring the dictionary to be populated
with all of the possible values of a data type unlike its later
refinement LZW, and which has fewer comparison reqirements during encoding
than its earlier counterpart LZ77.
Lempel-Ziv 78
An LZ78 compressed Generator
.
Encoding
encode :: (Hashable a, Eq a) => [a] -> LZ78 aSource
O(n) Construct an LZ78-compressed Generator
using a HashMap
internally.
encodeOrd :: Ord a => [a] -> LZ78 aSource
O(n log n) Contruct an LZ78-compressed Generator
using a Map
internally.
encodeEq :: Eq a => [a] -> LZ78 aSource
O(n^2) Contruct an LZ78-compressed Generator
using a list internally, requires an instance of Eq,
less efficient than encode.