Codec.Compression.ShannonFano

Documentation

data DecodeTableError

Decode table error can happen when the wrong code table is provided.

Constructors

DecodeTableError

Instances

Eq DecodeTableError

Defined in Codec.Compression.ShannonFano

Methods

(==) :: DecodeTableError -> DecodeTableError -> Bool

(/=) :: DecodeTableError -> DecodeTableError -> Bool

Show DecodeTableError

Defined in Codec.Compression.ShannonFano

Methods

showsPrec :: Int -> DecodeTableError -> ShowS

show :: DecodeTableError -> String

showList :: [DecodeTableError] -> ShowS

frequency

Arguments

:: Input

Input string

-> Table Int

Resulting table

Gives the frequency table of all characters in a string.

probability

Arguments

:: Input

Input string

-> Table Float

Resulting table

Gives the probability table of all characters in a string.

genCodeTable

Arguments

:: Input

Input string

-> Table ByteString

Resulting code table

Generates a DecodeTable

compress

Arguments

:: Input

Input string

-> ByteString

Result compressed

Given a 'Table ByteString' compresses it by applying the Shannon-fano algorithm.

decompress

Arguments

:: ByteString

Coded input to decompress

-> Table ByteString

Code table associated with the input

-> Maybe Input

Result decompressed

Decompresses a compressed ByteString, given a code table

This fails if the code table does not have an entry for a given character.

compressToFile

Arguments

:: Handle

Handle from where data will be read

-> String

Output file name

-> IO ()

Reads contents from a handle and compresses it to a file.

The resulting files are: - '<filename>' <- binary compressed file - '<filename>.dat' <- contains the decoding table

decompressFromFile

Arguments

:: Handle

Handle from where compressed data will be read

-> Table ByteString

Decode table

-> String

Output file name

-> IO (Either DecodeTableError ())

Decompresses a file given a decoding table file and a compressed compressed file.