#327 Store OS information according to ZIP spec (and ISO-21320-1:2015)

[tom235]

According to official ZIP spec's chapter 4.4.3 version needed to extract (2 bytes) shall not contain any HostOS specifics.

There is no value in this information. It only leads to warnings or errors in other unzip applications as the relevant OS information is already stored in 4.4.2.2 version made by / current mappings

[Igor Pavlov]

Why do you think, that it's problem?
Did you check that value for all another zip programs?

[tom235]

Hi Igor

libzip uses 16bit field for version needed to extract, thus provides no
host os information in this field:
https://github.com/nih-at/libzip/blob/master/lib/zip_dirent.c#L1085

libarchive also uses 16bit field for version needed, thus no host os
information in this field:
https://github.com/libarchive/libarchive/blob/master/libarchive/archive_write_set_format_zip.c#L775
https://github.com/libarchive/libarchive/blob/master/libarchive/archive_write_set_format_zip.c#L814

same with info-zip

neither do zip files from windows contain such information.

That's why I ask you to drop this behaviour, because to me it seems odd.

I simply stumbled upon while comparing zips resulting from different
programs.

Best regards
Thomas

On Tue, Aug 7, 2018 at 9:29 AM Igor Pavlov ipavlov@users.sourceforge.net
wrote:

Why do you think, that it's problem?
Did you check that value for all another zip programs?

---

• [patches:#327] https://sourceforge.net/p/sevenzip/patches/327/ Store
  OS information according to ZIP spec (and ISO-21320-1:2015)*

Status: open
Group:
Created: Mon Aug 06, 2018 11:24 PM UTC by tom235
Last Updated: Mon Aug 06, 2018 11:24 PM UTC
Owner: nobody
Attachments:

• no_hostos_needed_to_extract.patch
  https://sourceforge.net/p/sevenzip/patches/327/attachment/no_hostos_needed_to_extract.patch
  (522 Bytes; text/x-patch)

According to official ZIP spec
https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT's chapter 4.4.3
version needed to extract (2 bytes) shall not contain any HostOS
specifics.

There is no value in this information. It only leads to warnings or errors
in other unzip applications as the relevant OS information is already
stored in 4.4.2.2 version made by / current mappings

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