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README for libarchive bundle. |
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|
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Questions? Issues? |
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* http://libarchive.googlecode.com/ is the home for ongoing |
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libarchive development, including issue tracker, additional |
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documentation, and links to the libarchive mailing lists. |
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|
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This distribution bundle includes the following components: |
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* libarchive: a library for reading and writing streaming archives |
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* tar: the 'bsdtar' program is a full-featured 'tar' |
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replacement built on libarchive |
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* cpio: the 'bsdcpio' program is a different interface to |
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essentially the same functionality |
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* examples: Some small example programs that you may find useful. |
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* examples/minitar: a compact sample demonstrating use of libarchive. |
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* contrib: Various items sent to me by third parties; |
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please contact the authors with any questions. |
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|
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The top-level directory contains the following information files: |
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* NEWS - highlights of recent changes |
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* COPYING - what you can do with this |
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* INSTALL - installation instructions |
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* README - this file |
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* configure - configuration script, see INSTALL for details. |
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* CMakeLists.txt - input for "cmake" build tool, see INSTALL |
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|
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The following files in the top-level directory are used by the |
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'configure' script: |
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* Makefile.am, aclocal.m4, configure.ac |
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- used to build this distribution, only needed by maintainers |
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* Makefile.in, config.h.in |
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- templates used by configure script |
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|
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Guide to Documentation installed by this system: |
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* bsdtar.1 explains the use of the bsdtar program |
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* bsdcpio.1 explains the use of the bsdcpio program |
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* libarchive.3 gives an overview of the library as a whole |
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* archive_read.3, archive_write.3, archive_write_disk.3, and |
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archive_read_disk.3 provide detailed calling sequences for the read |
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and write APIs |
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* archive_entry.3 details the "struct archive_entry" utility class |
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* archive_internals.3 provides some insight into libarchive's |
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internal structure and operation. |
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* libarchive-formats.5 documents the file formats supported by the library |
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* cpio.5, mtree.5, and tar.5 provide detailed information about these |
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popular archive formats, including hard-to-find details about |
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modern cpio and tar variants. |
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The manual pages above are provided in the 'doc' directory in |
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a number of different formats. |
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|
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You should also read the copious comments in "archive.h" and the |
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source code for the sample programs for more details. Please let us |
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know about any errors or omissions you find. |
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|
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Currently, the library automatically detects and reads the following fomats: |
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* GNU tar format (including GNU long filenames, long link names, and sparse files) |
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* Solaris 9 extended tar format (including ACLs) |
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* Old V7 tar archives |
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* POSIX ustar |
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* POSIX pax interchange format |
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* POSIX octet-oriented cpio |
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* SVR4 ASCII cpio |
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* POSIX octet-oriented cpio |
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* Binary cpio (big-endian or little-endian) |
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* ISO9660 CD-ROM images (with optional Rockridge or Joliet extensions) |
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* ZIP archives (with uncompressed or "deflate" compressed entries) |
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* GNU and BSD 'ar' archives |
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* 'mtree' format |
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* Microsoft CAB format |
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* LHA and LZH archives |
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* RAR archives |
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* XAR archives |
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|
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The library also detects and handles any of the following before evaluating the archive: |
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* uuencoded files |
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* files with RPM wrapper |
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* gzip compression |
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* bzip2 compression |
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* compress/LZW compression |
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* lzma, lzip, and xz compression |
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|
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The library can create archives in any of the following formats: |
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* POSIX ustar |
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* POSIX pax interchange format |
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* "restricted" pax format, which will create ustar archives except for |
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entries that require pax extensions (for long filenames, ACLs, etc). |
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* Old GNU tar format |
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* POSIX octet-oriented cpio |
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* SVR4 "newc" cpio |
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* shar archives |
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* ZIP archives (with uncompressed or "deflate" compressed entries) |
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* GNU and BSD 'ar' archives |
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* 'mtree' format |
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* ISO9660 format |
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* XAR archives |
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|
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When creating archives, the result can be filtered with any of the following: |
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* uuencode |
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* gzip compression |
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* bzip2 compression |
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* compress/LZW compression |
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* lzma, lzip, and xz compression |
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|
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Notes about the library architecture: |
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|
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* This is a heavily stream-oriented system. There is no direct |
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support for in-place modification or random access. |
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* The library is designed to be extended with new compression and |
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archive formats. The only requirement is that the format be |
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readable or writable as a stream and that each archive entry be |
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independent. There are articles on the libarchive Wiki explaining |
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how to extend libarchive. |
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* On read, compression and format are always detected automatically. |
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* I've attempted to minimize static link pollution. If you don't |
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explicitly invoke a particular feature (such as support for a |
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particular compression or format), it won't get pulled in. |
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In particular, if you don't explicitly enable a particular |
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compression or decompression support, you won't need to link |
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against the corresponding compression or decompression libraries. |
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This also reduces the size of statically-linked binaries in |
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environments where that matters. |
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|
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* On read, the library accepts whatever blocks you hand it. |
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Your read callback is free to pass the library a byte at a time |
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or mmap the entire archive and give it to the library at once. |
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On write, the library always produces correctly-blocked output. |
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|
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* The object-style approach allows you to have multiple archive streams |
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open at once. bsdtar uses this in its "@archive" extension. |
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|
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* The archive itself is read/written using callback functions. |
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You can read an archive directly from an in-memory buffer or |
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write it to a socket, if you wish. There are some utility |
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functions to provide easy-to-use "open file," etc, capabilities. |
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|
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* The read/write APIs are designed to allow individual entries |
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to be read or written to any data source: You can create |
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a block of data in memory and add it to a tar archive without |
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first writing a temporary file. You can also read an entry from |
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an archive and write the data directly to a socket. If you want |
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to read/write entries to disk, there are convenience functions to |
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make this especially easy. |
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|
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* Note: "pax interchange format" is really an extended tar format, |
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despite what the name says. |
