Difference between pages "Talk:Foremost" and "Gzip"

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>Foremost's authors have recommended that practitioners use Scalpel instead of Foremost.  
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{{expand}}
I think this was in the past, but foremost is still being maintained and developed and may yield even better results than scalpel today. --[[User:Jr|Jr]] 14:58, 18 April 2009 (UTC)
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: As one of the original developers of Foremost I'm curious why you think it's better than [[Scalpel]]. The last update to Foremost was in October 2008. As far as I know [[Nick Mikus]] would be the only person maintaining it. Perhaps you should ask him what the status is. [[User:Jessek|Jessek]] 17:53, 20 April 2009 (UTC)
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== File format ==
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The gzip file (.gz) format consists of:
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* a file header
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* optional extra headers, such as the original file name,
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* a body, containing a DEFLATE-compressed payload
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* an 8-byte footer, containing a CRC-32 checksum and the length of the original uncompressed data.
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=== File header ===
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The file header is 10 bytes in size and contains:
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{| class="wikitable"
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! align="left"| Offset
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! Size
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! Value
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! Description
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|-
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| 0
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| 2
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| 0x1f 0x8b
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| Signature (or identification byte 1 and 2)
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|-
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| 2
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| 1
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|
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| Compression Method
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|-
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| 3
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| 1
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|
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| Flags
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|-
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| 4
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| 4
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|
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| Last modification time <br> Contains a POSIX timestamp.
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|-
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| 8
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| 1
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|
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| Extra flags
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|-
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| 9
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| 1
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|
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| Operating system <br> Value that indicates on which operating system the gzip file was created.
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|}
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==== Extra flags ====
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If compression method is 8 the following extra flags can be defined:
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* 0x02 - compressor used maximum compression, slowest algorithm
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* 0x04 - compressor used fastest algorithm
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== External Links ==
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* [http://www.gzip.org/format.txt The gzip file format], by the [http://www.gzip.org/ gzip project]
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* [http://www.gzip.org/algorithm.txt The gzip compression algorithm], by the [http://www.gzip.org/ gzip project]
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* [http://tools.ietf.org/html/rfc1952 RFC1952: GZIP file format specification version 4.3], by [[IETF]]
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* [http://en.wikipedia.org/wiki/Gzip Wikipedia: gzip]
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[[Category:File Formats]]

Revision as of 02:31, 28 November 2013

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Please help to improve this article by expanding it.
Further information might be found on the discussion page.

File format

The gzip file (.gz) format consists of:

  • a file header
  • optional extra headers, such as the original file name,
  • a body, containing a DEFLATE-compressed payload
  • an 8-byte footer, containing a CRC-32 checksum and the length of the original uncompressed data.

File header

The file header is 10 bytes in size and contains:

Offset Size Value Description
0 2 0x1f 0x8b Signature (or identification byte 1 and 2)
2 1 Compression Method
3 1 Flags
4 4 Last modification time
Contains a POSIX timestamp.
8 1 Extra flags
9 1 Operating system
Value that indicates on which operating system the gzip file was created.

Extra flags

If compression method is 8 the following extra flags can be defined:

  • 0x02 - compressor used maximum compression, slowest algorithm
  • 0x04 - compressor used fastest algorithm

External Links