Flex is a tool for generating scanners. A scanner, sometimes called a tokenizer, is a program which recognizes lexical patterns in text. The flex program reads user-specified input files, or its standard input if no file names are given, for a description of a scanner to generate. The description is in the form of pairs of regular expressions and C code, called rules. Flex generates a C source file named, "lex.yy.c", which defines the function yylex(). The file "lex.yy.c" can be compiled and linked to produce an executable. When the executable is run, it analyzes its input for occurrences of text matching the regular expressions for each rule. Whenever it finds a match, it executes the corresponding C code.

oyacc is a portable version of the OpenBSD's yacc program, with no dependencies besides libc.

PackCC is a packrat parser generator for the C programming language. Its main features are:

• Generates a parser in C from a grammar described in a PEG.

• Gives your parser great efficiency by packrat parsing.

• Supports direct and indirect left-recursive grammar rules.

The grammar of your parser can be described in a PEG. The PEG is a top-down parsing language, and is similar to the regular-expression grammar. The PEG does not require tokenization to be a separate step, and tokenization rules can be written in the same way as any other grammar rules.

This package provides the yacc command, implemented as a symbolic link to the oyacc command from the same-named package.

re2c, Regular Expressions to Code is a flexible lexical analyser. Instead of using traditional table-driven approaches, it encodes a finite state machine directly in the code in the form of jumps and comparisons.

Reflex is a POSIX-compatible variant of the flex lexical scanner generator.

Berkeley Yacc is an LALR(1) parser generator. Yacc reads the grammar specification from a file and generates an LALR(1) parser for it. The parsers consist of a set of LALR(1) parsing tables and a driver routine written in the C programming language.

DParser is scannerless GLR parser generator. The form of the text to be parsed can be specified using a combination of regular expressions and grammar productions. Because of the parsing technique, a scannerless GLR parser based on the Tomita algorithm the grammar can be ambiguous, right or left recursive, have any number of null productions, and because there is no separate tokenizer, can include whitespace in terminals and have terminals which are prefixes of other terminals.

ZZipLib is a library based on zlib for accessing zip files.

Ziptime helps make .zip archives reproducible by replacing timestamps in the file header with a fixed time (1 January 2008).

``Extra fields'' are not changed, so you'll need to use the -X option to zip to prevent it from storing the ``universal time'' field.

zlib-ng is a zlib replacement with optimizations for next generation systems.

unshield is a tool and library for extracting .cab archives from InstallShield installers.

Lzlib is a C library for in-memory LZMA compression and decompression in the lzip format. It supports integrity checking of the decompressed data, and all functions are thread-safe. The library should never crash, even in case of corrupted input.

Minizip is a minimalistic library that supports compressing, extracting and viewing ZIP archives. This version is extracted from the zlib source.

lrzip is a compression utility that uses long-range redundancy reduction to improve the subsequent compression ratio of larger files. It can then further compress the result with the ZPAQ or LZMA algorithms for maximum compression, or LZO for maximum speed. This choice between size or speed allows for either better compression than even LZMA can provide, or a higher speed than gzip while compressing as well as bzip2.

Zstandard (zstd) is a lossless compression algorithm that combines very fast operation with a compression ratio comparable to that of zlib. In most scenarios, both compression and decompression can be performed in ‘real time’. The compressor can be configured to provide the most suitable trade-off between compression ratio and speed, without affecting decompression speed.

Archive huge numbers of files, or split massive tar archives into smaller chunks.

Squashfs is a highly compressed read-only file system for Linux. It compresses files, inodes, and directories with one of several compressors. All blocks are packed to minimize the data overhead, and block sizes of between 4K and 1M are supported. It is intended to be used for archival use, for live media, and for embedded systems where low overhead is needed.

The squashfs-tools-ng package offers alternative tooling to create and extract such file systems. It is not based on the older squashfs-tools package and its tools have different names:

1. gensquashfs produces SquashFS images from a directory or gen_init_cpio-like file listings and can generate SELinux labels.

2. rdsquashfs inspects and unpacks SquashFS images.

3. sqfs2tar and tar2sqfs convert between SquashFS and tarballs.

4. sqfsdiff compares the contents of two SquashFS images.

These commands are largely command-line wrappers around the included libsquashfs library that intends to make SquashFS available to other applications as an embeddable, extensible archive format.

Both the library and tools operate deterministically: same input will produce byte-for-byte identical output.

GNU Gzip provides data compression and decompression utilities; the typical extension is ".gz". Unlike the "zip" format, it compresses a single file; as a result, it is often used in conjunction with "tar", resulting in ".tar.gz" or ".tgz", etc.

Clzip is a compressor and decompressor for files in the lzip compression format (.lz), written as a single small C tool with no dependencies. This makes it well-suited to embedded and other systems without a C++ compiler, or for use in other applications like package managers. Clzip is intended to be fully compatible with the regular lzip package.

A data compression/decompression library for embedded/real-time systems.

Among its features are:

• Low memory usage (as low as 50 bytes.) It is useful for some cases with less than 50 bytes, and useful for many general cases with less than 300 bytes.

• Incremental, bounded CPU use. It can be used to chew on input data in arbitrarily tiny bites. This is a useful property in hard real-time environments.

• Can use either static or dynamic memory allocation.

QuaZIP is a simple C++ wrapper over Gilles Vollant's ZIP/UNZIP package that can be used to access ZIP archives. It uses Trolltech's Qt toolkit.

QuaZIP allows you to access files inside ZIP archives using QIODevice API, and that means that you can also use QTextStream, QDataStream or whatever you would like to use on your zipped files.

QuaZIP provides complete abstraction of the ZIP/UNZIP API, for both reading from and writing to ZIP archives.

ECM is a utility that converts ECM files, i.e., CD data files with their error correction data losslessly rearranged for better compression, to their original, binary CD format.

Parallel Zstandard (PZstandard or pzstd) is a multi-threaded implementation of the Zstandard compression algorithm. It is fully compatible with the original Zstandard file format and command-line interface, and can be used as a drop-in replacement.

Compression is distributed over multiple processor cores to improve performance, as is the decompression of data compressed in this manner. Data compressed by other implementations will only be decompressed by two threads: one performing the actual decompression, the other input and output.