zlib

Compression and decompression in the gzip and zlib formats

LTS Haskell 24.18:0.7.1.1
Stackage Nightly 2025-11-04:0.7.1.1
Latest on Hackage:0.7.1.1

See all snapshots zlib appears in

BSD-3-Clause licensed by Duncan Coutts
Maintained by Duncan Coutts, Andrew Lelechenko, Emily Pillmore, Herbert Valerio Riedel
This version can be pinned in stack with:zlib-0.7.1.1@sha256:cf2f8f91b10b635bdaa2c3010f40a5562a06ede24b92d819758e7f1b7d04f9f2,5206

Module documentation for 0.7.1.1

Depends on 2 packages(full list with versions):
base, bytestring

zlib CI Hackage

Compression and decompression in the gzip and zlib format

This package provides a pure interface for compressing and decompressing streams of data represented as lazy ByteStrings. It uses the zlib C library so it has high performance. It supports the zlib, gzip and raw compression formats.

It provides a convenient high level API suitable for most tasks and for the few cases where more control is needed it provides access to the full zlib feature set.

Changes

See also http://pvp.haskell.org/faq

0.7.1.1 Bodigrim [email protected] September 2025

  • Allow newer versions of dependencies.
  • Fix new GHC warnings.

0.7.1.0 Bodigrim [email protected] April 2024

  • Split zlib C sources into zlib-clib package (thanks @hasufell).
  • Use zlib-clib on Windows, unless pkg-config is available.

0.7.0.0 Bodigrim [email protected] February 2024

  • Bump bundled zlib to 1.3.1.
  • Hide deprecated constructors of CompressionLevel, Method, WindowBits, MemoryLevel, CompressionStrategy and Format.
  • Make WindowBits, MemoryLevel and CompressionLevel newtypes over Int.
  • Add smart constructors rleStrategy and fixedStrategy.
  • Add assorted Eq, Ord, Typeable and Generic instances.
  • Make flag pkg-config automatic and on by default.
  • Make flag bundled-c-zlib to take priority over pkg-config.
  • Do not force bundled-c-zlib on Windows, but force it for WASM.
  • Strip install-includes, do not install any headers.
  • Export DecompressError from non-internal modules.
  • Fix compression/decompression of ByteString chunks > 4G.
  • Flip flag non-blocking-ffi to be True be default.

0.6.3.0 Bodigrim [email protected] May 2022

  • Bump bundled zlib to 1.2.12, #48
  • Support base-4.17

0.6.2.3 Emily Pillmore [email protected] February 2021

  • Add support for bytestring-0.11.0.0

0.6.2.2 Julian Ospald [email protected] August 2020

  • Bump bundled zlib to 1.2.11, fixes #26
  • New build flag to force use of the bundled zlib C sources, #31
  • Simpler build support for ghcjs, #25
  • Add support for GHC 8.10 / base-4.14, #29

0.6.2.1 Herbert Valerio Riedel [email protected] August 2019

  • Add support for GHC 8.8 / base-4.13

0.6.2 Herbert Valerio Riedel [email protected] March 2018

  • New cabal flag ‘pkg-config’ for discovering ’zlib` via pkg-config(1) (#16)
  • Use CApiFFI where available for cross-compile friendliness (#14)
  • Change the window bits range from 8..15 to 9..15 (#11)

0.6.1.2 Herbert Valerio Riedel [email protected] October 2016

  • Fix a segfault when reading the stream multithreaded, #7
  • New experimental cabal flag ‘non-blocking-ffi’ for ‘safe’ ffi calls

0.6.1.1 Duncan Coutts [email protected] April 2015

  • Fixed building with GHC 7.0 and 7.2

0.6.0.2 Duncan Coutts [email protected] April 2015

  • Fixed building with GHC 7.0 and 7.2

0.6.1.0 Duncan Coutts [email protected] April 2015

  • Support for concatenated gzip files (multiple back-to-back streams)

0.6.0.1 Duncan Coutts [email protected] April 2015

  • Fixed building with older GHC
  • Fixed warnings with new GHC
  • Fixed building on Windows
  • Fixed testsuite

0.6.0.0 Duncan Coutts [email protected] April 2015

  • New incremental interface for compression and decompression
  • Provide access to unconsumed trailing data
  • Simplified structured error type, and instance of Exception
  • Updated bundled zlib C code to 1.2.8 (used on Windows)
  • Fixed memory leak of zlib z_stream C structure
  • More derived instances (Eq, Show, Typeable, Generic)

0.5.4.2 Duncan Coutts [email protected] November 2014

  • Builds with GHC 7.10

0.5.4.1 Duncan Coutts [email protected] February 2013

  • Force tail of input when finished decompressing, to help lazy IO

0.5.4.0 Duncan Coutts [email protected] September 2012

  • New support for zlib custom dictionaries