zlib-0.7.1.1: Compression and decompression in the gzip and zlib formats

Copyright | (c) 2006-2014 Duncan Coutts
License | BSD-style
Maintainer | duncan@community.haskell.org
Safe Haskell | Safe-Inferred
Language | Haskell2010

Codec.Compression.Zlib.Raw

Contents

- Simple compression and decompression
- Extended API with control over compression parameters
  - The compression parameter types

Description

Compression and decompression of data streams in the raw deflate format.

The format is described in detail in RFC #1951: http://www.ietf.org/rfc/rfc1951.txt

See also the zlib home page: http://zlib.net/

Synopsis

- compress :: ByteString -> ByteString
- decompress :: ByteString -> ByteString
- data DecompressError
  - = TruncatedInput
  - | DictionaryRequired
  - | DictionaryMismatch
  - | DataFormatError String
- compressWith :: CompressParams -> ByteString -> ByteString
- decompressWith :: DecompressParams -> ByteString -> ByteString
- data CompressParams = CompressParams {
  - compressLevel :: !CompressionLevel
  - compressMethod :: !Method
  - compressWindowBits :: !WindowBits
  - compressMemoryLevel :: !MemoryLevel
  - compressStrategy :: !CompressionStrategy
  - compressBufferSize :: !Int
  - compressDictionary :: Maybe ByteString
  }
- defaultCompressParams :: CompressParams
- data DecompressParams = DecompressParams {
  - decompressWindowBits :: !WindowBits
  - decompressBufferSize :: !Int
  - decompressDictionary :: Maybe ByteString
  - decompressAllMembers :: Bool
  }
- defaultDecompressParams :: DecompressParams
- newtype CompressionLevel = CompressionLevel Int
- defaultCompression :: CompressionLevel
- noCompression :: CompressionLevel
- bestSpeed :: CompressionLevel
- bestCompression :: CompressionLevel
- compressionLevel :: Int -> CompressionLevel
- data Method
- deflateMethod :: Method
- newtype WindowBits = WindowBits Int
- defaultWindowBits :: WindowBits
- windowBits :: Int -> WindowBits
- newtype MemoryLevel = MemoryLevel Int
- defaultMemoryLevel :: MemoryLevel
- minMemoryLevel :: MemoryLevel
- maxMemoryLevel :: MemoryLevel
- memoryLevel :: Int -> MemoryLevel
- data CompressionStrategy
- defaultStrategy :: CompressionStrategy
- filteredStrategy :: CompressionStrategy
- huffmanOnlyStrategy :: CompressionStrategy
- rleStrategy :: CompressionStrategy
- fixedStrategy :: CompressionStrategy

# Simple compression and decompression

compress :: ByteString -> ByteString Source #

Compress a stream of data into the raw deflate format.

decompress :: ByteString -> ByteString Source #

Decompress a stream of data in the raw deflate format.

data DecompressError Source #

The possible error cases when decompressing a stream.

This can be `show`n to give a human readable error message.

Constructors

TruncatedInput | The compressed data stream ended prematurely. This may happen if the input data stream was truncated.
DictionaryRequired | It is possible to do zlib compression with a custom dictionary. This allows slightly higher compression ratios for short files. However such compressed streams require the same dictionary when decompressing. This error is for when we encounter a compressed stream that needs a dictionary, and it's not provided.
DictionaryMismatch | If the stream requires a dictionary and you provide one with the wrong `DictionaryHash` then you will get this error.
DataFormatError String | If the compressed data stream is corrupted in any way then you will get this error, for example if the input data just isn't a compressed zlib data stream. In particular if the data checksum turns out to be wrong then you will get all the decompressed data but this error at the end, instead of the normal successful `StreamEnd`.

#### Instances

Instances details

Exception DecompressError Source # |
Instance details Defined in Codec.Compression.Zlib.Internal Methods toException :: DecompressError -> SomeException Source # fromException :: SomeException -> Maybe DecompressError Source # displayException :: DecompressError -> String Source # backtraceDesired :: DecompressError -> Bool Source #
Generic DecompressError Source # |

Instance details

Defined in Codec.Compression.Zlib.Internal

Associated Types

type Rep DecompressError | Since: zlib-0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep DecompressError = D1 ('MetaData "DecompressError" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) ((C1 ('MetaCons "TruncatedInput" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "DictionaryRequired" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "DictionaryMismatch" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "DataFormatError" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String))))

Methods

from :: DecompressError -> Rep DecompressError x Source #

to :: Rep DecompressError x -> DecompressError Source #

Show DecompressError Source # |
Instance details Defined in Codec.Compression.Zlib.Internal Methods showsPrec :: Int -> DecompressError -> ShowS Source # show :: DecompressError -> String Source # showList :: [DecompressError] -> ShowS Source #
Eq DecompressError Source # |
Instance details Defined in Codec.Compression.Zlib.Internal Methods (==) :: DecompressError -> DecompressError -> Bool Source # (/=) :: DecompressError -> DecompressError -> Bool Source #
Ord DecompressError Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

Methods

compare :: DecompressError -> DecompressError -> Ordering Source #

(<) :: DecompressError -> DecompressError -> Bool Source #

(<=) :: DecompressError -> DecompressError -> Bool Source #

(>) :: DecompressError -> DecompressError -> Bool Source #

(>=) :: DecompressError -> DecompressError -> Bool Source #

max :: DecompressError -> DecompressError -> DecompressError Source #

min :: DecompressError -> DecompressError -> DecompressError Source #

type Rep DecompressError Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep DecompressError = D1 ('MetaData "DecompressError" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) ((C1 ('MetaCons "TruncatedInput" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "DictionaryRequired" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "DictionaryMismatch" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "DataFormatError" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String))))

# Extended API with control over compression parameters

compressWith :: CompressParams -> ByteString -> ByteString Source #

Like `compress` but with the ability to specify various decompression parameters.

decompressWith :: DecompressParams -> ByteString -> ByteString Source #

Like `decompress` but with the ability to specify various decompression parameters.

data CompressParams Source #

The full set of parameters for compression. The defaults are `defaultCompressParams`.

The `compressBufferSize` is the size of the first output buffer containing the compressed data. If you know an approximate upper bound on the size of the compressed data then setting this parameter can save memory. The default compression output buffer size is `16k`. If your estimate is wrong it does not matter too much, the default buffer size will be used for the remaining chunks.

Constructors

CompressParams |

Fields

- compressLevel :: !CompressionLevel
- compressMethod :: !Method
- compressWindowBits :: !WindowBits
- compressMemoryLevel :: !MemoryLevel
- compressStrategy :: !CompressionStrategy
- compressBufferSize :: !Int
- compressDictionary :: Maybe ByteString

#### Instances

Instances details

Generic CompressParams Source # |

Instance details

Defined in Codec.Compression.Zlib.Internal

Associated Types

type Rep CompressParams | Since: zlib-0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep CompressParams = D1 ('MetaData "CompressParams" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "CompressParams" 'PrefixI 'True) ((S1 ('MetaSel ('Just "compressLevel") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 CompressionLevel) :*: (S1 ('MetaSel ('Just "compressMethod") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Method) :*: S1 ('MetaSel ('Just "compressWindowBits") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 WindowBits))) :*: ((S1 ('MetaSel ('Just "compressMemoryLevel") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 MemoryLevel) :*: S1 ('MetaSel ('Just "compressStrategy") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 CompressionStrategy)) :*: (S1 ('MetaSel ('Just "compressBufferSize") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int) :*: S1 ('MetaSel ('Just "compressDictionary") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe ByteString))))))

Methods

from :: CompressParams -> Rep CompressParams x Source #

to :: Rep CompressParams x -> CompressParams Source #

Show CompressParams Source # |
Instance details Defined in Codec.Compression.Zlib.Internal Methods showsPrec :: Int -> CompressParams -> ShowS Source # show :: CompressParams -> String Source # showList :: [CompressParams] -> ShowS Source #
Eq CompressParams Source # | Since: 0.7.0.0
Instance details Defined in Codec.Compression.Zlib.Internal Methods (==) :: CompressParams -> CompressParams -> Bool Source # (/=) :: CompressParams -> CompressParams -> Bool Source #
Ord CompressParams Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

Methods

compare :: CompressParams -> CompressParams -> Ordering Source #

(<) :: CompressParams -> CompressParams -> Bool Source #

(<=) :: CompressParams -> CompressParams -> Bool Source #

(>) :: CompressParams -> CompressParams -> Bool Source #

(>=) :: CompressParams -> CompressParams -> Bool Source #

max :: CompressParams -> CompressParams -> CompressParams Source #

min :: CompressParams -> CompressParams -> CompressParams Source #

type Rep CompressParams Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep CompressParams = D1 ('MetaData "CompressParams" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "CompressParams" 'PrefixI 'True) ((S1 ('MetaSel ('Just "compressLevel") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 CompressionLevel) :*: (S1 ('MetaSel ('Just "compressMethod") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Method) :*: S1 ('MetaSel ('Just "compressWindowBits") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 WindowBits))) :*: ((S1 ('MetaSel ('Just "compressMemoryLevel") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 MemoryLevel) :*: S1 ('MetaSel ('Just "compressStrategy") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 CompressionStrategy)) :*: (S1 ('MetaSel ('Just "compressBufferSize") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int) :*: S1 ('MetaSel ('Just "compressDictionary") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe ByteString))))))

defaultCompressParams :: CompressParams Source #

The default set of parameters for compression. This is typically used with `compressWith` or `compressWith` with specific parameters overridden.

data DecompressParams Source #

The full set of parameters for decompression. The defaults are `defaultDecompressParams`.

The `decompressBufferSize` is the size of the first output buffer, containing the uncompressed data. If you know an exact or approximate upper bound on the size of the decompressed data then setting this parameter can save memory. The default decompression output buffer size is `32k`. If your estimate is wrong it does not matter too much, the default buffer size will be used for the remaining chunks.

One particular use case for setting the `decompressBufferSize` is if you know the exact size of the decompressed data and want to produce a strict `ByteString`. The compression and decompression functions use lazy `ByteString`s but if you set the `decompressBufferSize` correctly then you can generate a lazy `ByteString` with exactly one chunk, which can be converted to a strict `ByteString` in `O(1)` time using ``concat` . `toChunks``.

Constructors

DecompressParams |

Fields

- decompressWindowBits :: !WindowBits
- decompressBufferSize :: !Int
- decompressDictionary :: Maybe ByteString
- decompressAllMembers :: Bool

#### Instances

Instances details

Generic DecompressParams Source # |

Instance details

Defined in Codec.Compression.Zlib.Internal

Associated Types

type Rep DecompressParams | Since: zlib-0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep DecompressParams = D1 ('MetaData "DecompressParams" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "DecompressParams" 'PrefixI 'True) ((S1 ('MetaSel ('Just "decompressWindowBits") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 WindowBits) :*: S1 ('MetaSel ('Just "decompressBufferSize") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int)) :*: (S1 ('MetaSel ('Just "decompressDictionary") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe ByteString)) :*: S1 ('MetaSel ('Just "decompressAllMembers") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Bool))))

Methods

from :: DecompressParams -> Rep DecompressParams x Source #

to :: Rep DecompressParams x -> DecompressParams Source #

Show DecompressParams Source # |
Instance details Defined in Codec.Compression.Zlib.Internal Methods showsPrec :: Int -> DecompressParams -> ShowS Source # show :: DecompressParams -> String Source # showList :: [DecompressParams] -> ShowS Source #
Eq DecompressParams Source # | Since: 0.7.0.0
Instance details Defined in Codec.Compression.Zlib.Internal Methods (==) :: DecompressParams -> DecompressParams -> Bool Source # (/=) :: DecompressParams -> DecompressParams -> Bool Source #
Ord DecompressParams Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

Methods

compare :: DecompressParams -> DecompressParams -> Ordering Source #

(<) :: DecompressParams -> DecompressParams -> Bool Source #

(<=) :: DecompressParams -> DecompressParams -> Bool Source #

(>) :: DecompressParams -> DecompressParams -> Bool Source #

(>=) :: DecompressParams -> DecompressParams -> Bool Source #

max :: DecompressParams -> DecompressParams -> DecompressParams Source #

min :: DecompressParams -> DecompressParams -> DecompressParams Source #

type Rep DecompressParams Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Internal

type Rep DecompressParams = D1 ('MetaData "DecompressParams" "Codec.Compression.Zlib.Internal" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "DecompressParams" 'PrefixI 'True) ((S1 ('MetaSel ('Just "decompressWindowBits") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 WindowBits) :*: S1 ('MetaSel ('Just "decompressBufferSize") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int)) :*: (S1 ('MetaSel ('Just "decompressDictionary") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe ByteString)) :*: S1 ('MetaSel ('Just "decompressAllMembers") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Bool))))

defaultDecompressParams :: DecompressParams Source #

The default set of parameters for decompression. This is typically used with `decompressWith` or `decompressWith` with specific parameters overridden.

## The compression parameter types

newtype CompressionLevel Source #

The compression level parameter controls the amount of compression. This is a trade-off between the amount of compression and the time required to do the compression.

Constructors

CompressionLevel Int |

#### Instances

Instances details

Generic CompressionLevel Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Associated Types

type Rep CompressionLevel |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep CompressionLevel = D1 ('MetaData "CompressionLevel" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "CompressionLevel" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

Methods

from :: CompressionLevel -> Rep CompressionLevel x Source #

to :: Rep CompressionLevel x -> CompressionLevel Source #

Show CompressionLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods showsPrec :: Int -> CompressionLevel -> ShowS Source # show :: CompressionLevel -> String Source # showList :: [CompressionLevel] -> ShowS Source #
Eq CompressionLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods (==) :: CompressionLevel -> CompressionLevel -> Bool Source # (/=) :: CompressionLevel -> CompressionLevel -> Bool Source #
Ord CompressionLevel Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

compare :: CompressionLevel -> CompressionLevel -> Ordering Source #

(<) :: CompressionLevel -> CompressionLevel -> Bool Source #

(<=) :: CompressionLevel -> CompressionLevel -> Bool Source #

(>) :: CompressionLevel -> CompressionLevel -> Bool Source #

(>=) :: CompressionLevel -> CompressionLevel -> Bool Source #

max :: CompressionLevel -> CompressionLevel -> CompressionLevel Source #

min :: CompressionLevel -> CompressionLevel -> CompressionLevel Source #

type Rep CompressionLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep CompressionLevel = D1 ('MetaData "CompressionLevel" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "CompressionLevel" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

defaultCompression :: CompressionLevel Source #

The default `CompressionLevel`.

noCompression :: CompressionLevel Source #

No compression, just a block copy.

bestSpeed :: CompressionLevel Source #

The fastest compression method (less compression).

bestCompression :: CompressionLevel Source #

The slowest compression method (best compression).

compressionLevel :: Int -> CompressionLevel Source #

A specific compression level in the range `0..9`. Throws an error for arguments outside of this range.

- 0 stands for `noCompression`,
- 1 stands for `bestSpeed`,
- 6 stands for `defaultCompression`,
- 9 stands for `bestCompression`.

data Method Source #

The compression method

#### Instances

Instances details

Bounded Method Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods minBound :: Method Source # maxBound :: Method Source #
Enum Method Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

succ :: Method -> Method Source #

pred :: Method -> Method Source #

toEnum :: Int -> Method Source #

fromEnum :: Method -> Int Source #

enumFrom :: Method -> [Method] Source #

enumFromThen :: Method -> Method -> [Method] Source #

enumFromTo :: Method -> Method -> [Method] Source #

enumFromThenTo :: Method -> Method -> Method -> [Method] Source #

Generic Method Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Associated Types

type Rep Method |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep Method = D1 ('MetaData "Method" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "Deflated" 'PrefixI 'False) (U1 :: Type -> Type))

Methods

from :: Method -> Rep Method x Source #

to :: Rep Method x -> Method Source #

Show Method Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods showsPrec :: Int -> Method -> ShowS Source # show :: Method -> String Source # showList :: [Method] -> ShowS Source #
Eq Method Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods (==) :: Method -> Method -> Bool Source # (/=) :: Method -> Method -> Bool Source #
Ord Method Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods compare :: Method -> Method -> Ordering Source # (<) :: Method -> Method -> Bool Source # (<=) :: Method -> Method -> Bool Source # (>) :: Method -> Method -> Bool Source # (>=) :: Method -> Method -> Bool Source # max :: Method -> Method -> Method Source # min :: Method -> Method -> Method Source #
type Rep Method Source # |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep Method = D1 ('MetaData "Method" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) (C1 ('MetaCons "Deflated" 'PrefixI 'False) (U1 :: Type -> Type))

deflateMethod :: Method Source #

The only method supported in this version of zlib. Indeed it is likely to be the only method that ever will be supported.

newtype WindowBits Source #

This specifies the size of the compression window. Larger values of this parameter result in better compression at the expense of higher memory usage.

The compression window size is the value of the the window bits raised to the power 2. The window bits must be in the range `9..15` which corresponds to compression window sizes of 512b to 32Kb. The default is 15 which is also the maximum size.

The total amount of memory used depends on the window bits and the `MemoryLevel`. See the `MemoryLevel` for the details.

Constructors

WindowBits Int |

#### Instances

Instances details

Generic WindowBits Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Associated Types

type Rep WindowBits |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep WindowBits = D1 ('MetaData "WindowBits" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "WindowBits" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

Methods

from :: WindowBits -> Rep WindowBits x Source #

to :: Rep WindowBits x -> WindowBits Source #

Show WindowBits Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods showsPrec :: Int -> WindowBits -> ShowS Source # show :: WindowBits -> String Source # showList :: [WindowBits] -> ShowS Source #
Eq WindowBits Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods (==) :: WindowBits -> WindowBits -> Bool Source # (/=) :: WindowBits -> WindowBits -> Bool Source #
Ord WindowBits Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

compare :: WindowBits -> WindowBits -> Ordering Source #

(<) :: WindowBits -> WindowBits -> Bool Source #

(<=) :: WindowBits -> WindowBits -> Bool Source #

(>) :: WindowBits -> WindowBits -> Bool Source #

(>=) :: WindowBits -> WindowBits -> Bool Source #

max :: WindowBits -> WindowBits -> WindowBits Source #

min :: WindowBits -> WindowBits -> WindowBits Source #

type Rep WindowBits Source # |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep WindowBits = D1 ('MetaData "WindowBits" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "WindowBits" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

defaultWindowBits :: WindowBits Source #

The default `WindowBits`. Equivalent to ``windowBits` 15`. which is also the maximum size.

windowBits :: Int -> WindowBits Source #

A specific compression window size, specified in bits in the range `9..15`. Throws an error for arguments outside of this range.

newtype MemoryLevel Source #

The `MemoryLevel` parameter specifies how much memory should be allocated for the internal compression state. It is a trade-off between memory usage, compression ratio and compression speed. Using more memory allows faster compression and a better compression ratio.

The total amount of memory used for compression depends on the `WindowBits` and the `MemoryLevel`. For decompression it depends only on the `WindowBits`. The totals are given by the functions:

    compressTotal windowBits memLevel = 4 * 2^windowBits + 512 * 2^memLevel
    decompressTotal windowBits = 2^windowBits

For example, for compression with the default `windowBits = 15` and `memLevel = 8` uses `256Kb`. So for example a network server with 100 concurrent compressed streams would use `25Mb`. The memory per stream can be halved (at the cost of somewhat degraded and slower compression) by reducing the `windowBits` and `memLevel` by one.

Decompression takes less memory, the default `windowBits = 15` corresponds to just `32Kb`.

Constructors

MemoryLevel Int |

#### Instances

Instances details

Generic MemoryLevel Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Associated Types

type Rep MemoryLevel |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep MemoryLevel = D1 ('MetaData "MemoryLevel" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "MemoryLevel" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

Methods

from :: MemoryLevel -> Rep MemoryLevel x Source #

to :: Rep MemoryLevel x -> MemoryLevel Source #

Show MemoryLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods showsPrec :: Int -> MemoryLevel -> ShowS Source # show :: MemoryLevel -> String Source # showList :: [MemoryLevel] -> ShowS Source #
Eq MemoryLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods (==) :: MemoryLevel -> MemoryLevel -> Bool Source # (/=) :: MemoryLevel -> MemoryLevel -> Bool Source #
Ord MemoryLevel Source # | Since: 0.7.0.0

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

compare :: MemoryLevel -> MemoryLevel -> Ordering Source #

(<) :: MemoryLevel -> MemoryLevel -> Bool Source #

(<=) :: MemoryLevel -> MemoryLevel -> Bool Source #

(>) :: MemoryLevel -> MemoryLevel -> Bool Source #

(>=) :: MemoryLevel -> MemoryLevel -> Bool Source #

max :: MemoryLevel -> MemoryLevel -> MemoryLevel Source #

min :: MemoryLevel -> MemoryLevel -> MemoryLevel Source #

type Rep MemoryLevel Source # |
Instance details Defined in Codec.Compression.Zlib.Stream type Rep MemoryLevel = D1 ('MetaData "MemoryLevel" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'True) (C1 ('MetaCons "MemoryLevel" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int)))

defaultMemoryLevel :: MemoryLevel Source #

The default `MemoryLevel`. Equivalent to ``memoryLevel` 8`.

minMemoryLevel :: MemoryLevel Source #

Use minimum memory. This is slow and reduces the compression ratio. Equivalent to ``memoryLevel` 1`.

maxMemoryLevel :: MemoryLevel Source #

Use maximum memory for optimal compression speed. Equivalent to ``memoryLevel` 9`.

memoryLevel :: Int -> MemoryLevel Source #

A specific memory level in the range `1..9`. Throws an error for arguments outside of this range.

data CompressionStrategy Source #

The strategy parameter is used to tune the compression algorithm.

The strategy parameter only affects the compression ratio but not the correctness of the compressed output even if it is not set appropriately.

#### Instances

Instances details

Bounded CompressionStrategy Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods minBound :: CompressionStrategy Source # maxBound :: CompressionStrategy Source #
Enum CompressionStrategy Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

succ :: CompressionStrategy -> CompressionStrategy Source #

pred :: CompressionStrategy -> CompressionStrategy Source #

toEnum :: Int -> CompressionStrategy Source #

fromEnum :: CompressionStrategy -> Int Source #

enumFrom :: CompressionStrategy -> [CompressionStrategy] Source #

enumFromThen :: CompressionStrategy -> CompressionStrategy -> [CompressionStrategy] Source #

enumFromTo :: CompressionStrategy -> CompressionStrategy -> [CompressionStrategy] Source #

enumFromThenTo :: CompressionStrategy -> CompressionStrategy -> CompressionStrategy -> [CompressionStrategy] Source #

Generic CompressionStrategy Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Associated Types

type Rep CompressionStrategy |

Instance details

Defined in Codec.Compression.Zlib.Stream

type Rep CompressionStrategy = D1 ('MetaData "CompressionStrategy" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) ((C1 ('MetaCons "DefaultStrategy" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Filtered" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "HuffmanOnly" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "RLE" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Fixed" 'PrefixI 'False) (U1 :: Type -> Type))))

Methods

from :: CompressionStrategy -> Rep CompressionStrategy x Source #

to :: Rep CompressionStrategy x -> CompressionStrategy Source #

Show CompressionStrategy Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods showsPrec :: Int -> CompressionStrategy -> ShowS Source # show :: CompressionStrategy -> String Source # showList :: [CompressionStrategy] -> ShowS Source #
Eq CompressionStrategy Source # |
Instance details Defined in Codec.Compression.Zlib.Stream Methods (==) :: CompressionStrategy -> CompressionStrategy -> Bool Source # (/=) :: CompressionStrategy -> CompressionStrategy -> Bool Source #
Ord CompressionStrategy Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

Methods

compare :: CompressionStrategy -> CompressionStrategy -> Ordering Source #

(<) :: CompressionStrategy -> CompressionStrategy -> Bool Source #

(<=) :: CompressionStrategy -> CompressionStrategy -> Bool Source #

(>) :: CompressionStrategy -> CompressionStrategy -> Bool Source #

(>=) :: CompressionStrategy -> CompressionStrategy -> Bool Source #

max :: CompressionStrategy -> CompressionStrategy -> CompressionStrategy Source #

min :: CompressionStrategy -> CompressionStrategy -> CompressionStrategy Source #

type Rep CompressionStrategy Source # |

Instance details

Defined in Codec.Compression.Zlib.Stream

type Rep CompressionStrategy = D1 ('MetaData "CompressionStrategy" "Codec.Compression.Zlib.Stream" "zlib-0.7.1.1-9slKnSVaKOMKfNAnZzR5ey" 'False) ((C1 ('MetaCons "DefaultStrategy" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Filtered" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "HuffmanOnly" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "RLE" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Fixed" 'PrefixI 'False) (U1 :: Type -> Type))))

defaultStrategy :: CompressionStrategy Source #

Use this default compression strategy for normal data.

filteredStrategy :: CompressionStrategy Source #

Use the filtered compression strategy for data produced by a filter (or predictor). Filtered data consists mostly of small values with a somewhat random distribution. In this case, the compression algorithm is tuned to compress them better. The effect of this strategy is to force more Huffman coding and less string matching; it is somewhat intermediate between `defaultStrategy` and `huffmanOnlyStrategy`.

huffmanOnlyStrategy :: CompressionStrategy Source #

Use the Huffman-only compression strategy to force Huffman encoding only (no string match).

rleStrategy :: CompressionStrategy Source #

Use `rleStrategy` to limit match distances to one (run-length encoding). `rleStrategy` is designed to be almost as fast as `huffmanOnlyStrategy`, but give better compression for PNG image data.

Since: 0.7.0.0

fixedStrategy :: CompressionStrategy Source #

`fixedStrategy` prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.

Since: 0.7.0.0