fq/format/zip/zip.md

Supports ZIP64.

## Timestamp and time zones

The timestamp accessed via `.local_files[].last_modification` is encoded in ZIP files using [MS-DOS representation](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-dosdatetimetovarianttime) which lacks a known time zone. Probably the local time/date was used at creation. The `unix_guess` field in `last_modification` is a guess assuming the local time zone was UTC at creation.

### References
- https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
- https://opensource.apple.com/source/zip/zip-6/unzip/unzip/proginfo/extra.fld
- https://formats.kaitai.io/dos_datetime/
- https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-dosdatetimetovarianttime
help,doc: Use markdown for format documentation again Markdown is used as is in online documentation and in cli the markdown decoder is used to decode and the some jq code massages it into something cli friendly. Was just too much of a mess to have doc in jq. 2022-09-10 19:28:54 +03:00			`Supports ZIP64.`

zip: Fix incorrect time/date, add extended timestamp and refactor MSDOS time/date was read in wrong order and also did not take into account that the bit ranges in the shortis are in little-endian. Remodel modification_time/date to be one struct with fat_time, fat_date LE shorts and then synthetic values for day, hours, minute etc and also a unix field with the timestamp as unix time. Also refactor and clenaup extra fields/extended code a bit. Fixes #792 2023-10-21 19:11:56 +03:00			`## Timestamp and time zones`

			The timestamp accessed via `.local_files[].last_modification` is encoded in ZIP files using [MS-DOS representation](https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-dosdatetimetovarianttime) which lacks a known time zone. Probably the local time/date was used at creation. The `unix_guess` field in `last_modification` is a guess assuming the local time zone was UTC at creation.

doc: Fix format sections a bit 2022-09-11 10:55:30 +03:00			`### References`
help,doc: Use markdown for format documentation again Markdown is used as is in online documentation and in cli the markdown decoder is used to decode and the some jq code massages it into something cli friendly. Was just too much of a mess to have doc in jq. 2022-09-10 19:28:54 +03:00			`- https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT`
			`- https://opensource.apple.com/source/zip/zip-6/unzip/unzip/proginfo/extra.fld`
zip: Fix incorrect time/date, add extended timestamp and refactor MSDOS time/date was read in wrong order and also did not take into account that the bit ranges in the shortis are in little-endian. Remodel modification_time/date to be one struct with fat_time, fat_date LE shorts and then synthetic values for day, hours, minute etc and also a unix field with the timestamp as unix time. Also refactor and clenaup extra fields/extended code a bit. Fixes #792 2023-10-21 19:11:56 +03:00			`- https://formats.kaitai.io/dos_datetime/`
			`- https://learn.microsoft.com/en-us/windows/win32/api/oleauto/nf-oleauto-dosdatetimetovarianttime`