Data compression and decompression algorithms

Types[ edit ] It is possible to compress many types of digital data in a way that reduces the size of a computer file needed to store it, or the bandwidth needed to transmit it, with no loss of the full information contained in the original file.

Data compression and decompression algorithms

Decompression requires no additional memory. See below for some rough timings. Both the source code and the compressed data format are designed to be portable across platforms. UCL implements a number of algorithms with the following features: Requires no memory for decompression.

History of Lossless Data Compression Algorithms - Engineering and Technology History Wiki

The decompressors can be squeezed into less than bytes of code. Focuses on compression levels for generating pre-compressed data which achieve a quite competitive compression ratio.

Data compression and decompression algorithms

Allows you to dial up extra compression at a speed cost in the compressor. The speed of the decompressor is not reduced. Algorithm is thread safe.

Information Theory

UCL supports in-place decompression. Special licenses for commercial and other applications are available by contacting the author. Here are some original timings on an ancient Intel Pentium back in the year In fact I expect a implementation too happen soon in the process of extending the UPX executable packer.

The compressors currently require at least bit integers. While porting them to more restricted environments such as bit DOS should be possible without too much effort this is not considered important at this time.PPP Compression Control Protocol (CCP) and Compression Algorithms (Page 1 of 4) PPP is, of course, primarily used to provide data link layer connectivity to physical serial links.

In information technology, lossy compression or irreversible compression is the class of data encoding methods that uses inexact approximations and partial data discarding to represent the content.

These techniques are used to reduce data size for storing, handling, and transmitting content. The different versions of the photo of the cat to the right show how higher degrees of approximation. Table — Chunk fields; Length: A four-byte unsigned integer giving the number of bytes in the chunk's data field.

The length counts only the data field, not itself, the .

Data compression and decompression algorithms

Decompression is the process of restoring compressed data to its original form. Data decompression is required in almost all cases of compressed data, including lossy and lossless compression. Data Compression introduction basic coding schemes an application entropy allows for lossless compression of random data.

If this is true, Perpetual Motion Machines Universal data compression algorithms are the analog of perpetual motion machines.

Status of this document

Closed-cycle mill by Robert Fludd, Gravity engine by Bob Schadewald Reference. zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating zlib data format is itself portable across platforms.

Unlike the LZW compression method used in Unix compress(1) and in the GIF image format, the compression method currently used in. UCL data compression library