file/magic/Magdir/zip

#------------------------------------------------------------------------------
# $File: zip,v 1.8 2021/10/24 15:53:56 christos Exp $
# zip:  file(1) magic for zip files; this is not use
# Note the version of magic in archive is currently stronger, this is
# just an example until negative offsets are supported better
# Note:	All fields unless otherwise noted are unsigned!

# Zip Central Directory record
0	name		zipcd
>0	string		PK\001\002	Zip archive data
!:mime	application/zip
# no "made by" in local file header with PK\3\4 magic
>>4	leshort		x		\b, made by
>>4	use		zipversion
>>4	use		ziphost
# inside ./archive 1.151 called "at least" zipversion "to extract"
>>6	leshort		x		\b, extract using at least
>>6	use		zipversion
# This is DOS date like: ledate 21:00:48 19 Dec 2001 != DOS 00:00 1 Jan 2010 ~ 0000213C
>>12	ulelong		x		\b, last modified
>>14	lemsdosdate	x		\b, last modified %s
>>12	lemsdostime	x		%s
# uncompressed size of 1st entry; FFffFFff means real value stored in ZIP64 record
>>24	ulelong		!0xFFffFFff	\b, uncompressed size %u
# inside ./archive 1.151 called "compression method="zipcompression
>>10	leshort		x		\b, method=
>>10	use		zipcompression

# URL:		https://en.wikipedia.org/wiki/Zip_(file_format)
# reference:	https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT (Version: 6.3.9)
# Zip known compressions
0	name		zipcompression
>0	leshort		0		\bstore
>0	leshort		1		\bShrinking
>0	leshort		6		\bImploding
>0	leshort		7		\bTokenizing
>0	leshort		8		\bdeflate
>0	leshort		9		\bdeflate64
>0	leshort		10		\bLibrary imploding
#>0	leshort		11 		\bReserved by PKWARE
>0	leshort		12		\bbzip2
#>0	leshort		13 		\bReserved by PKWARE
>0	leshort		14		\blzma
#>0	leshort		15 		\bReserved by PKWARE
>0	leshort		16		\bCMPSC (IBM z/OS)
#>0	leshort		17 		\bReserved by PKWARE
>0	leshort		18		\bIBM TERSE
>0	leshort		19		\bIBM LZ77 (z/Architecture)
>0	leshort		20		\bZstd (deprecated)
>0	leshort		93		\bZstd
>0	leshort		94		\bMP3
>0	leshort		95		\bxz
>0	leshort		96		\bJpeg
>0	leshort		97		\bWavPack
>0	leshort		98		\bPPMd
>0	leshort		99		\bAES Encrypted
>0	default		x
>>0	leshort		x		\b[%#x]

# Zip known versions
0	name		zipversion
# The lower byte indicates the ZIP version of this file. The value/10 indicates
# the major version number, and the value mod 10 is the minor version number.
>0	ubyte/10	x		v%u
>0	ubyte%10	x		\b.%u
# >0	leshort		0x09		v0.9
# >0	leshort		0x0a		v1.0
# >0	leshort		0x0b		v1.1
# >0	leshort		0x14		v2.0
# >0	leshort		0x15		v2.1
# >0	leshort		0x19		v2.5
# >0	leshort		0x1b		v2.7
# >0	leshort		0x2d		v4.5
# >0	leshort		0x2e		v4.6
# >0	leshort		0x32		v5.0
# >0	leshort		0x33		v5.1
# >0	leshort		0x34		v5.2
# >0	leshort		0x3d		v6.1
# >0	leshort		0x3e		v6.2
# >0	leshort		0x3f		v6.3
# >0	default		x
# >>0	leshort		x		v?[%#x]

#	display compatible host system name of ZIP archive
0	name		ziphost
# The upper byte indicates the compatibility of the file attribute information.
# If the file is compatible with MS-DOS (v 2.04g) then this value will be zero.
#>1	ubyte		0		DOS
>1	ubyte		1 		Amiga
>1	ubyte		2		OpenVMS
>1	ubyte		3		UNIX
>1	ubyte		4		VM/CMS
>1	ubyte		6		OS/2
>1	ubyte		7		Macintosh
>1	ubyte		11		MVS
>1	ubyte		13		Acorn Risc
>1	ubyte		16		BeOS
>1	ubyte		17		Tandem
# 9 untested
>1	ubyte		5		Atari ST
>1	ubyte		8		Z-System
>1	ubyte		9		CP/M
>1	ubyte		10		Windows NTFS
>1	ubyte		12		VSE
>1	ubyte		14		VFAT
>1	ubyte		15		alternate MVS
>1	ubyte		18		OS/400
>1	ubyte		19		OS X
# unused
#>1	ubyte		>19		unused %#x

# Zip End Of Central Directory record
# GRR: wrong for ZIP with comment archive
-22	string		PK\005\006
#>4	uleshort	!0xFFff		\b, %u disks
#>6	uleshort	!0xFFff		\b, central directory disk %u
#>8	uleshort	!0xFFff		\b, %u central directories on this disk
#>10	uleshort	!0xFFff		\b, %u central directories
#>12	ulelong		!0xFFffFFff	\b, %u central directory bytes
# offset of central directory
#>16	ulelong		x		\b, central directory offset %#x
>(16.l)	use		zipcd
# archive comment length n
#>>20	uleshort	>0		\b, comment length %u
# archive comment
>>20	pstring/l	>0		\b, %s