libarchive

libarchive is a cross-platform, open-source library written in C that provides APIs to read and write a variety of archive formats and to access compressed data streams transparently. It is designed for software that needs to handle archiving without implementing each format itself and is not a standalone archiver but a reusable component for embedding archiving capabilities in other programs.

The library supports multiple archive formats, including tar, cpio, pax, and zip, among others. It can read and write both uncompressed archives and compressed variants using common compressors such as gzip, bzip2, and xz. Libarchive offers a streaming interface, enabling applications to process archives entry by entry and to work with metadata via archive_entry objects.

Typical usage patterns involve creating an archive read or write object, opening a source or destination, and then iterating over entries with functions such as archive_read_next_header to obtain metadata and read data, or using archive_write functions to add new entries to an archive. The API emphasizes memory management and portability, allowing for operations from file descriptors, file paths, or in-memory buffers.

Originating from BSD projects, libarchive has been widely adopted across UNIX-like systems and serves as the underlying library for tools such as the bsdtar tar utility. It is maintained as an open-source project with contributions from volunteers and users who rely on its multi-format, multi-compression capabilities to handle archival tasks in diverse environments.

Licensing and availability: libarchive is distributed under a permissive BSD-style license and is maintained as an open-source project with ongoing development in its official repository.