compress revision 110949
150472Speter 233975Sjdp#------------------------------------------------------------------------------ 333975Sjdp# compress: file(1) magic for pure-compression formats (no archives) 433975Sjdp# 533975Sjdp# compress, gzip, pack, compact, huf, squeeze, crunch, freeze, yabba, etc. 633975Sjdp# 780019Sobrien# Formats for various forms of compressed data 884947Sobrien# Formats for "compress" proper have been moved into "compress.c", 954748Smarcel# because it tries to uncompress it to figure out what's inside. 1084902Sobrien 1144360Simp# standard unix compress 1233975Sjdp0 string \037\235 compress'd data 1333975Sjdp>2 byte&0x80 >0 block compressed 1433975Sjdp>2 byte&0x1f x %d bits 1584902Sobrien 1633975Sjdp# gzip (GNU zip, not to be confused with Info-ZIP or PKWARE zip archiver) 1784902Sobrien# Edited by Chris Chittleborough <cchittleborough@yahoo.com.au>, March 2002 1884902Sobrien# * Original filename is only at offset 10 if "extra field" absent 1933975Sjdp# * Produce shorter output - notably, only report compression methods 2084902Sobrien# other than 8 ("deflate", the only method defined in RFC 1952). 2133975Sjdp0 string \037\213 gzip compressed data 2233975Sjdp>2 byte <8 \b, reserved method 2333975Sjdp>2 byte >8 \b, unknown method 2484902Sobrien>3 byte &0x01 \b, ASCII 2544360Simp>3 byte &0x02 \b, continuation 2684902Sobrien>3 byte &0x04 \b, extra field 2734495Sjdp>3 byte&0xC =0x08 2884902Sobrien>>10 string x \b, was "%s" 2984902Sobrien>9 byte =0x00 \b, from MS-DOS 3084902Sobrien>9 byte =0x01 \b, from Amiga 3134495Sjdp>9 byte =0x02 \b, from VMS 3244360Simp>9 byte =0x03 \b, from Unix 3344360Simp>9 byte =0x05 \b, from Atari 3434495Sjdp>9 byte =0x06 \b, from OS/2 3534495Sjdp>9 byte =0x07 \b, from MacOS 3684902Sobrien>9 byte =0x0A \b, from Tops/20 3735709Sjb>9 byte =0x0B \b, from Win/32 3852927Sjb>3 byte &0x10 \b, comment 3952927Sjb>3 byte &0x20 \b, encrypted 4084902Sobrien### >4 ledate x last modified: %s, 4152927Sjb>8 byte 2 \b, max compression 4252927Sjb>8 byte 4 \b, max speed 4352927Sjb 4435709Sjb# packed data, Huffman (minimum redundancy) codes on a byte-by-byte basis 4535709Sjb0 string \037\036 packed data 4635709Sjb>2 belong >1 \b, %d characters originally 4734495Sjdp>2 belong =1 \b, %d character originally 4835709Sjb# 49# This magic number is byte-order-independent. XXX - Does that mean this 50# is big-endian, little-endian, either, or that you can't tell? 51# this short is valid for SunOS 520 short 017437 old packed data 53 54# XXX - why *two* entries for "compacted data", one of which is 55# byte-order independent, and one of which is byte-order dependent? 56# 570 short 0x1fff compacted data 58# This string is valid for SunOS (BE) and a matching "short" is listed 59# in the Ultrix (LE) magic file. 600 string \377\037 compacted data 610 short 0145405 huf output 62 63# bzip2 640 string BZh bzip2 compressed data 65>3 byte >47 \b, block size = %c00k 66 67# squeeze and crunch 68# Michael Haardt <michael@cantor.informatik.rwth-aachen.de> 690 beshort 0x76FF squeezed data, 70>4 string x original name %s 710 beshort 0x76FE crunched data, 72>2 string x original name %s 730 beshort 0x76FD LZH compressed data, 74>2 string x original name %s 75 76# Freeze 770 string \037\237 frozen file 2.1 780 string \037\236 frozen file 1.0 (or gzip 0.5) 79 80# SCO compress -H (LZH) 810 string \037\240 SCO compress -H (LZH) data 82 83# European GSM 06.10 is a provisional standard for full-rate speech 84# transcoding, prI-ETS 300 036, which uses RPE/LTP (residual pulse 85# excitation/long term prediction) coding at 13 kbit/s. 86# 87# There's only a magic nibble (4 bits); that nibble repeats every 33 88# bytes. This isn't suited for use, but maybe we can use it someday. 89# 90# This will cause very short GSM files to be declared as data and 91# mismatches to be declared as data too! 92#0 byte&0xF0 0xd0 data 93#>33 byte&0xF0 0xd0 94#>66 byte&0xF0 0xd0 95#>99 byte&0xF0 0xd0 96#>132 byte&0xF0 0xd0 GSM 06.10 compressed audio 97 98# bzip a block-sorting file compressor 99# by Julian Seward <sewardj@cs.man.ac.uk> and others 100# 1010 string BZ bzip compressed data 102>2 byte x \b, version: %c 103>3 string =1 \b, compression block size 100k 104>3 string =2 \b, compression block size 200k 105>3 string =3 \b, compression block size 300k 106>3 string =4 \b, compression block size 400k 107>3 string =5 \b, compression block size 500k 108>3 string =6 \b, compression block size 600k 109>3 string =7 \b, compression block size 700k 110>3 string =8 \b, compression block size 800k 111>3 string =9 \b, compression block size 900k 112 113# lzop from <markus.oberhumer@jk.uni-linz.ac.at> 1140 string \x89\x4c\x5a\x4f\x00\x0d\x0a\x1a\x0a lzop compressed data 115>9 beshort <0x0940 116>>9 byte&0xf0 =0x00 - version 0. 117>>9 beshort&0x0fff x \b%03x, 118>>13 byte 1 LZO1X-1, 119>>13 byte 2 LZO1X-1(15), 120>>13 byte 3 LZO1X-999, 121## >>22 bedate >0 last modified: %s, 122>>14 byte =0x00 os: MS-DOS 123>>14 byte =0x01 os: Amiga 124>>14 byte =0x02 os: VMS 125>>14 byte =0x03 os: Unix 126>>14 byte =0x05 os: Atari 127>>14 byte =0x06 os: OS/2 128>>14 byte =0x07 os: MacOS 129>>14 byte =0x0A os: Tops/20 130>>14 byte =0x0B os: WinNT 131>>14 byte =0x0E os: Win32 132>9 beshort >0x0939 133>>9 byte&0xf0 =0x00 - version 0. 134>>9 byte&0xf0 =0x10 - version 1. 135>>9 byte&0xf0 =0x20 - version 2. 136>>9 beshort&0x0fff x \b%03x, 137>>15 byte 1 LZO1X-1, 138>>15 byte 2 LZO1X-1(15), 139>>15 byte 3 LZO1X-999, 140## >>25 bedate >0 last modified: %s, 141>>17 byte =0x00 os: MS-DOS 142>>17 byte =0x01 os: Amiga 143>>17 byte =0x02 os: VMS 144>>17 byte =0x03 os: Unix 145>>17 byte =0x05 os: Atari 146>>17 byte =0x06 os: OS/2 147>>17 byte =0x07 os: MacOS 148>>17 byte =0x0A os: Tops/20 149>>17 byte =0x0B os: WinNT 150>>17 byte =0x0E os: Win32 151 152# 4.3BSD-Quasijarus Strong Compression 153# http://minnie.tuhs.org/Quasijarus/compress.html 1540 string \037\241 Quasijarus strong compressed data 155 156# From: Cory Dikkers <cdikkers@swbell.net> 1570 string XPKF Amiga xpkf.library compressed data 1580 string PP11 Power Packer 1.1 compressed data 1590 string PP20 Power Packer 2.0 compressed data, 160>4 belong 0x09090909 fast compression 161>4 belong 0x090A0A0A mediocre compression 162>4 belong 0x090A0B0B good compression 163>4 belong 0x090A0C0C very good compression 164>4 belong 0x090A0C0D best compression 165 166# 7z archiver, from Thomas Klausner (wiz@danbala.tuwien.ac.at) 167# http://www.7-zip.org or DOC/7zFormat.txt 168# 1690 string 7z\274\257\047\034 7z archive data, 170>6 byte x version %d 171>7 byte x \b.%d 172