zlib

Information about zlib

zlib is a software library used for data compression. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. The first public version, 0.9, was released on 1 May 1995 and was originally intended for use with libpng image library. It is free software, distributed under the zlib license.

As of March 2007, zlib is included in Coverity’s Department of Homeland Security-sponsored ongoing examination of select open-source projects.[1]

Software using zlib

Today, zlib is something of a de facto standard, to the point that zlib and DEFLATE are often used interchangeably in standards documents. Hundreds of applications for Unix-like operating systems such as Linux rely on it for compression and it is increasingly used on other platforms, such as Microsoft Windows and the Palm OS. A few notable applications are:
  • The Linux kernel, where it is used to implement compressed network protocols, compressed file systems and to decompress the kernel image itself at boot time.
  • libpng, the reference implementation for the PNG image format, which specifies DEFLATE as the stream compression for its bitmap data.
  • The Apache HTTP server, which uses zlib to implement HTTP/1.1.
  • The OpenSSH client and server, which rely on zlib to perform the optional compression offered by the Secure Shell protocol.
  • The OpenSSL and GnuTLS security libraries, which can optionally use zlib to compress TLS connections.
  • The FFmpeg multimedia library, which uses zlib to read and write the DEFLATE-compressed parts of stream formats such as Matroska.
  • The rsync remote file synchronizer, which uses zlib to implement optional protocol compression.
  • The RPM package manager, which uses zlib to unpack files from compressed RPM packages.
zlib is also used in many embedded devices because the code is portable, liberally-licensed and has a relatively small memory footprint.

See also

References

1. ^ [1]

External links

library is a collection of subprograms used to develop software. Libraries contain "helper" code and data, which provide services to independent programs. This allows code and data to be shared and changed in a modular fashion.
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data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an un-encoded representation would use through use of specific encoding schemes.
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In computer science, abstraction is a mechanism and practice to reduce and factor out details so that one can focus on a few concepts at a time.

The following English definition of abstraction helps to understand how this term applies to Computer Science, IT and Objects - i.
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DEFLATE is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. It was originally defined by Phil Katz for version 2 of his PKZIP archiving tool, and was later specified in RFC 1951.
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In mathematics, computing, linguistics, and related disciplines, an algorithm is a finite list of well-defined instructions for accomplishing some task that, given an initial state, will proceed through a well-defined series of successive states, eventually terminating in an
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gzip

File extension: .gz
MIME type: application/x-gzip
Developed by: Jean-loup Gailly and Mark Adler
Type of format: data compression

gzip is a software application used for file compression.
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May 1 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.

Events

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19th century - 20th century - 21st century
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1992 1993 1994 - 1995 - 1996 1997 1998

Year 1995 (MCMXCV
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libpng is the official PNG reference library (originally called pnglib). It is a platform-independent library that contains C functions for handling PNG images. It is developed by Guy Eric Schalnat, Andreas Dilger, Glenn Randers-Pehrson and others. libpng is dependent on zlib.
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Free software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions only to ensure that further recipients can also do these things.
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zlib license
Author:
Version:
Copyright on the license:
Publication date: 1 May 1995
OSI approved: Yes
Debian approved: Yes
Free Software: Yes
FSF says GPL compatible: Yes
Copyleft: No

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Coverity is a software vendor in San Francisco. It was incorporated in November 2002, by the founders Dawson Engler, Seth Hallem, Ben Chelf, Andy Chou and Dave Park. Coverity is a boot-strap startup, meaning there is no venture capital or angel investors.
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United States
Department of Homeland Security

Motto: "Preserving our Freedom"
Agency overview
Formed November 25, 2002

Headquarters Nebraska Avenue Complex
Employees 208,000 (2007)
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Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification.
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Linux (pronunciation: IPA: /ˈlɪnʊks/, lin-uks) is a Unix-like computer operating system. Linux is one of the most prominent examples of free software and open source development; its underlying source code can be
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Microsoft Windows

Screenshot of Windows Vista Ultimate, the latest version of Microsoft Windows.
Company/developer: Microsoft Corporation
OS family: MS-DOS/9x-based, Windows CE, Windows NT
Source model: Closed source

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Palm OS (also known as Garnet OS) is an embedded operating system initially developed by U.S. Robotics' owned Palm Computing, Inc. for personal digital assistants (PDAs) in 1996. Palm OS is designed for ease of use with a touchscreen-based graphical user interface.
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kernel is the central component of most computer operating systems (OS). Its responsibilities include managing the system's resources (the communication between hardware and software components).
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file system (often also written as filesystem) is a method for storing and organizing computer files and the data they contain to make it easy to find and access them.
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libpng is the official PNG reference library (originally called pnglib). It is a platform-independent library that contains C functions for handling PNG images. It is developed by Guy Eric Schalnat, Andreas Dilger, Glenn Randers-Pehrson and others. libpng is dependent on zlib.
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PNG may stand for:
  • Papua New Guinea, a country in Oceania, occupying the eastern half of the island of New Guinea and numerous off-shore islands.
  • Portable Network Graphics, a bitmapped image format that employs lossless data compression.

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bitmap or pixmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits.
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Apache HTTP Server, commonly referred to simply as Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. Apache was the first viable alternative to the Netscape Communications Corporation web server (currently known as Sun Java
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HTTP compression is a capability built into both web servers and web browsers, to make better use of available bandwidth. HTTP protocol data is compressed before it is sent from the server: compliant browsers will announce what methods are supported to the server before downloading
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OpenSSH (OpenBSD Secure Shell) is a set of computer programs providing encrypted communication sessions over a computer network using the ssh protocol. It was created as an open source alternative to the proprietary Secure Shell software suite offered by SSH
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Secure Shell or SSH is a network protocol that allows data to be exchanged over a secure channel between two computers. Encryption provides confidentiality and integrity of data.
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OpenSSL is an open source implementation of the SSL and TLS protocols. The core library (written in the C programming language) implements the basic cryptographic functions and provides various utility functions.
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GnuTLS, the GNU Transport Layer Security Library, is a free software implementation of the SSL and TLS protocols. Its purpose is to offer an application programming interface (API) for applications to enable secure communication protocols over their network transport layer.
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Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers.
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FFmpeg is a collection of software libraries that can record, convert and stream digital audio and video in numerous formats. It includes libavcodec, an audio/video codec library used by several other projects, and libavformat
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