monoids-0.1.31: Monoids, specialized containers and a general map/reduce framework Source code Contents Index

Data.Generator.Compressive.RLE Portability portable Stability experimental Maintainer ekmett@gmail.com

Description

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. Run length encoding can do so for long runs of identical inputs.

Synopsis

module Data.Generator newtype RLE f a = RLE { getRLE :: f (Run a) } data Run a = Run a !Int decode :: Foldable f => RLE f a -> [a] encode :: (Generator c, Eq (Elem c)) => c -> RLE Seq (Elem c) encodeList :: Eq a => [a] -> RLE [] a prop_decode_encode :: (Generator c, Eq (Elem c)) => c -> Bool prop_decode_encodeList :: Eq a => [a] -> Bool

Documentation

module Data.Generator

newtype RLE f a Source

A Generator which supports efficient mapReduce operations over run-length encoded data. Constructors RLE getRLE :: f (Run a) Instances Eq a => Reducer a (RLE Seq a) Eq a => Module Natural (RLE Seq a) Eq a => RightModule Natural (RLE Seq a) Eq a => LeftModule Natural (RLE Seq a) Functor f => Functor (RLE f) Eq a => Monoid (RLE Seq a) Foldable f => Generator (RLE f a)

data Run a Source

A single run with a strict length. Constructors Run a !Int Instances Functor Run Pointed Run

decode :: Foldable f => RLE f a -> [a] Source

encode :: (Generator c, Eq (Elem c)) => c -> RLE Seq (Elem c) Source

encodeList :: Eq a => [a] -> RLE [] a Source

naive left to right encoder, which can handle infinite data

prop_decode_encode :: (Generator c, Eq (Elem c)) => c -> Bool Source

prop_decode_encodeList :: Eq a => [a] -> Bool Source

QuickCheck property: decode . encode = id

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