# $OpenBSD: compress,v 1.4 2004/06/03 03:14:19 tedu Exp $ #------------------------------------------------------------------------------ # compress: file(1) magic for pure-compression formats (no archives) # # compress, gzip, pack, compact, huf, squeeze, crunch, freeze, yabba, etc. # # Formats for various forms of compressed data # Formats for "compress" proper have been moved into "compress.c", # because it tries to uncompress it to figure out what's inside. # standard unix compress 0 string \037\235 compress'd data >2 byte&0x80 >0 block compressed >2 byte&0x1f x %d bits # gzip (GNU zip, not to be confused with Info-ZIP or PKWARE zip archiver) # Edited by Chris Chittleborough , March 2002 # * Original filename is only at offset 10 if "extra field" absent # * Produce shorter output - notably, only report compression methods # other than 8 ("deflate", the only method defined in RFC 1952). 0 string \037\213 gzip compressed data >2 byte <8 \b, reserved method >2 byte >8 \b, unknown method >3 byte &0x01 \b, ASCII >3 byte &0x02 \b, continuation >3 byte &0x04 \b, extra field >3 byte&0xC =0x08 >>10 string x \b, was "%s" >9 byte =0x00 \b, from MS-DOS >9 byte =0x01 \b, from Amiga >9 byte =0x02 \b, from VMS >9 byte =0x03 \b, from Unix >9 byte =0x05 \b, from Atari >9 byte =0x06 \b, from OS/2 >9 byte =0x07 \b, from MacOS >9 byte =0x0A \b, from Tops/20 >9 byte =0x0B \b, from Win/32 >3 byte &0x10 \b, comment >3 byte &0x20 \b, encrypted ### >4 ledate x last modified: %s, >8 byte 2 \b, max compression >8 byte 4 \b, max speed # packed data, Huffman (minimum redundancy) codes on a byte-by-byte basis 0 string \037\036 packed data >2 belong >1 \b, %d characters originally >2 belong =1 \b, %d character originally # # This magic number is byte-order-independent. 0 short 0x1f1f old packed data # XXX - why *two* entries for "compacted data", one of which is # byte-order independent, and one of which is byte-order dependent? # 0 short 0x1fff compacted data # This string is valid for SunOS (BE) and a matching "short" is listed # in the Ultrix (LE) magic file. 0 string \377\037 compacted data 0 short 0145405 huf output # bzip2 0 string BZh bzip2 compressed data >3 byte >47 \b, block size = %c00k # squeeze and crunch # Michael Haardt 0 beshort 0x76FF squeezed data, >4 string x original name %s 0 beshort 0x76FE crunched data, >2 string x original name %s 0 beshort 0x76FD LZH compressed data, >2 string x original name %s # Freeze 0 string \037\237 frozen file 2.1 0 string \037\236 frozen file 1.0 (or gzip 0.5) # SCO compress -H (LZH) 0 string \037\240 SCO compress -H (LZH) data # European GSM 06.10 is a provisional standard for full-rate speech # transcoding, prI-ETS 300 036, which uses RPE/LTP (residual pulse # excitation/long term prediction) coding at 13 kbit/s. # # There's only a magic nibble (4 bits); that nibble repeats every 33 # bytes. This isn't suited for use, but maybe we can use it someday. # # This will cause very short GSM files to be declared as data and # mismatches to be declared as data too! #0 byte&0xF0 0xd0 data #>33 byte&0xF0 0xd0 #>66 byte&0xF0 0xd0 #>99 byte&0xF0 0xd0 #>132 byte&0xF0 0xd0 GSM 06.10 compressed audio # bzip a block-sorting file compressor # by Julian Seward and others # 0 string BZ bzip compressed data >2 byte x \b, version: %c >3 string =1 \b, compression block size 100k >3 string =2 \b, compression block size 200k >3 string =3 \b, compression block size 300k >3 string =4 \b, compression block size 400k >3 string =5 \b, compression block size 500k >3 string =6 \b, compression block size 600k >3 string =7 \b, compression block size 700k >3 string =8 \b, compression block size 800k >3 string =9 \b, compression block size 900k # lzop from 0 string \x89\x4c\x5a\x4f\x00\x0d\x0a\x1a\x0a lzop compressed data >9 beshort <0x0940 >>9 byte&0xf0 =0x00 - version 0. >>9 beshort&0x0fff x \b%03x, >>13 byte 1 LZO1X-1, >>13 byte 2 LZO1X-1(15), >>13 byte 3 LZO1X-999, ## >>22 bedate >0 last modified: %s, >>14 byte =0x00 os: MS-DOS >>14 byte =0x01 os: Amiga >>14 byte =0x02 os: VMS >>14 byte =0x03 os: Unix >>14 byte =0x05 os: Atari >>14 byte =0x06 os: OS/2 >>14 byte =0x07 os: MacOS >>14 byte =0x0A os: Tops/20 >>14 byte =0x0B os: WinNT >>14 byte =0x0E os: Win32 >9 beshort >0x0939 >>9 byte&0xf0 =0x00 - version 0. >>9 byte&0xf0 =0x10 - version 1. >>9 byte&0xf0 =0x20 - version 2. >>9 beshort&0x0fff x \b%03x, >>15 byte 1 LZO1X-1, >>15 byte 2 LZO1X-1(15), >>15 byte 3 LZO1X-999, ## >>25 bedate >0 last modified: %s, >>17 byte =0x00 os: MS-DOS >>17 byte =0x01 os: Amiga >>17 byte =0x02 os: VMS >>17 byte =0x03 os: Unix >>17 byte =0x05 os: Atari >>17 byte =0x06 os: OS/2 >>17 byte =0x07 os: MacOS >>17 byte =0x0A os: Tops/20 >>17 byte =0x0B os: WinNT >>17 byte =0x0E os: Win32 # 4.3BSD-Quasijarus Strong Compression # http://minnie.tuhs.org/Quasijarus/compress.html 0 string \037\241 Quasijarus strong compressed data # From: Cory Dikkers 0 string XPKF Amiga xpkf.library compressed data 0 string PP11 Power Packer 1.1 compressed data 0 string PP20 Power Packer 2.0 compressed data, >4 belong 0x09090909 fast compression >4 belong 0x090A0A0A mediocre compression >4 belong 0x090A0B0B good compression >4 belong 0x090A0C0C very good compression >4 belong 0x090A0C0D best compression # 7z archiver, from Thomas Klausner (wiz@danbala.tuwien.ac.at) # http://www.7-zip.org or DOC/7zFormat.txt # 0 string 7z\274\257\047\034 7z archive data, >6 byte x version %d >7 byte x \b.%d # AFX compressed files (Wolfram Kleff) 2 string -afx- AFX compressed file data