xar (archiver)
| Internet media type |
application/x-xar archive file format |
|---|---|
| Extended from | XML, gzip |
XAR (short for eXtensible ARchive format) is an
pax files.[2]
One
File structure
The file consists of three sections, the header, the table of contents and the heap. All fields are stored in
big endian order.[4]
Header
| Offset# | Size (in bytes) |
Purpose |
|---|---|---|
| 0 | 4 | File signature used to identify the file format as Xar. This should always equal xar!
|
| 4 | 2 | Header size |
| 6 | 2 | Version of Xar format to use. Currently there is only version 1. |
| 8 | 8 | Length of the TOC compressed data. |
| 16 | 8 | Length of the TOC uncompressed data. |
| 24 | 4 | Checksum algorithm: |
| 28 | 0, 4 , 36 | sometimes padding bytes or checksum algorithm name |
Table of contents
Xar is different from
lzma compression method.[5]
Example Table of contents
<?xml version="1.0" encoding="UTF-8"?>
<xar>
<toc>
<checksum style="sha1">
<offset>0</offset>
<size>20</size>
</checksum>
<file id="1">
<group>staff</group>
<gid>20</gid>
<user>joe</user>
<uid>501</uid>
<mode>0755</mode>
<type>directory</type>
<name>com.foobar</name>
<file id="2">
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0775</mode>
<type>directory</type>
<name>Contents</name>
<file id="3">
<data>
<length>428</length>
<offset>20</offset>
<size>1005</size>
<encoding style="application/x-gzip"/>
<archived-checksum style="SHA1">a5f6f1461213a904f831d4ef6f214638342842ed</archived-checksum>
<extracted-checksum style="SHA1">21d21a0c90378248ce0dfb6f345376d1b00d65fc</extracted-checksum>
</data>
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0664</mode>
<type>file</type>
<name>Info.plist</name>
</file>
<file id="4">
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0775</mode>
<type>directory</type>
<name>Resources</name>
<file id="5">
<data>
<length>14868</length>
<offset>448</offset>
<size>274432</size>
<encoding style="application/x-gzip"/>
<archived-checksum style="SHA1">efe5c97921de7ccc5aebc158d158e9d4280d6814</archived-checksum>
<extracted-checksum style="SHA1">45c8be42d1d9afdb57ddd5e9311453010ec46161</extracted-checksum>
</data>
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0664</mode>
<type>file</type>
<name>foobar</name>
</file>
<file id="6">
<data>
<length>17635</length>
<offset>15316</offset>
<size>45056</size>
<encoding style="application/x-gzip"/>
<archived-checksum style="SHA1">3c761ffcc81ee6e232e4f4a1c4a81654c26c4e52</archived-checksum>
<extracted-checksum style="SHA1">0ea31f8ef0e5987a1838a64ab5c26ebf3ee4bc37</extracted-checksum>
</data>
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0664</mode>
<type>file</type>
<name>docSet.skidx</name>
</file>
<file id="7">
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0775</mode>
<type>directory</type>
<name>Documents</name>
<file id="8">
<data>
<length>35790</length>
<offset>32951</offset>
<size>209242</size>
<encoding style="application/x-gzip"/>
<archived-checksum style="SHA1">5242cd71585c34e722932f324706f8c00e1ae0c5</archived-checksum>
<extracted-checksum style="SHA1">c0e013e53d829511835e2b429abb5198731e9a3e</extracted-checksum>
</data>
<group></group>
<gid>20</gid>
<user></user>
<uid>501</uid>
<mode>0664</mode>
<type>file</type>
<name>foobar.html</name>
</file>
</file>
</file>
</file>
</file>
</toc>
</xar>
References
- ^ a b "application/x-xar". Retrieved 2019-03-19.
- ^ Nabble – xar in Mac OS X Archived February 7, 2007, at the Wayback Machine
- ^ RPM 5 package manager
- ^ a b "Xarformat · mackyle/Xar Wiki". GitHub.
- ^ a b Braun, Rob; Fuller, Landon; Leimbach, David; Van Vechten, Kevin (2015-06-04). "xar - eXtensible ARchiver mojave man page". Retrieved 2019-03-26.
- ^ "Google Code Archive - Long-term storage for Google Code Project Hosting".
External links
- Original Xar project (unmaintained)
- fork from original project (unmaintained)
- Apple xar on GitHub
| Archiving only | |
|---|---|
| Compression only | |
| Archiving and compression | |
| Software packaging and distribution | |
| Document packaging and distribution | |
 | This computer data storage-related software article is a stub. You can help Wikipedia by expanding it. |