Dec 092017
 
Complete file formats of archivers ARC PAK LZH ZOO DWC GIF SIT BQY etc. An excellent reference for archive programmers.
File ARCHIVES.ZIP from The Programmer’s Corner in
Category Tutorials + Patches
Complete file formats of archivers ARC PAK LZH ZOO DWC GIF SIT BQY etc. An excellent reference for archive programmers.
File Name File Size Zip Size Zip Type
ARCHIVES.ME 1907 644 deflated
ARCHIVES.TXT 45696 9937 deflated

Download File ARCHIVES.ZIP Here

Contents of the ARCHIVES.TXT file




[[[[[[[[[ ARCHIVE FORMATS AND DATA ]]]]]]]]]

(C) 1989 Raymond Clay
Permision to freely distribute and modify
is granted so long as credit is given
and all of the text through the disclaimer
is retained and unchanged

October 31, 1989

If you want to submit corrections, changes or source code (in plain ASCII),
you can reach me via:


CIS : 74730,1344
GEnie : R.CLAY1
AppleLink : Raymond6
StarText : 209287
DISCLAIMER:

I make no garuntees of any kind about the accuracy or adequacey of this
information for any purpose, nor am I responsible for the consequences of
using this information in any manner.

Oh, for a less litiginous world!


**************************************************


CONTENTS PAGE
--------------------------------------------------
ARC/PAK Format ................................ 2

Binary ][ Format .............................. 3

DWC Format .................................... 5

GIF Format .................................... 6

LZH Format .................................... 8

NuFX Format ................................... 9

PackIt Format ................................. 13

StuffIt ....................................... 13

ZIP Format .................................... 15

ZOO Format .................................... 19

Time Value Formats ............................ 20

Extended Files ................................ 20

Filenames ..................................... 20








ARC/PAK Page 2
=======

System of Origin : IBM


Original author : Thom Henderson

FILE FORMAT
-----------

file header 1
file 1
file header 2
file 2
.
.
file header n
file n
EOF


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 ARCID DB $1A
01 ARCMTD DB 00 ;Method
02 ARCFNT DS 12 ;filename
0E DB 00
0F ARCNSZ HEX 00000000 ;Compressed size
13 ARCDAT DW 0000 ;File date (MSDOS)
15 ARCTIM DW 0000 ;File time (MSDOS)
17 ARCCRC DW 0000
19 ARCOSZ HEX 00000000 ;Uncompressed size
1D ARCFIL DS ARCNSZ


COMPRESSION METHOD
------------------

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
Stored 0 No compression used
Packed 1 Repeated running length encoding (RLE)
Squeezed 2 Huffman encoding
Crunched 3 LZW with 4K buffer, 12 bits codes
Crunched 4 First packing, then LZW 4K buffer with 12 bits
Crunched 5 Packing, LZW, 4K buffer, vari len (9-12 bits)
Squashed 6 LZW, 8K buffer, variable length (9-13 bits)
Crushed 7 Packing, then LZW 8K buffer, 2-13 bits (PAK 1.0)
Distill 8 Dynamic Huffman with 8K buffer (PAK 2.0)


POSITIONING IN FILE
-------------------

Begining of File Data = Begining of File Header + $1D

Next File Header = Begining of File Header + $1D + ARCNSZ
or
= Begining of File Data + ARCNSZ

**************************************************


BINARY ][ Page 3
=========

System of Origin : Apple ][

Original Author : Gary Little

FILE FORMAT
-----------


file header 1
file 1
file header 2
file 2
.
.
file header n
file n
EOF


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 B2ID1 DB $A ;ID bytes
01 B2ID2 ASC 'GL' ;authors initials - Gary Little
03 B2ACS DB 00 ;access code
04 B2FTYP DB 00 ;file type
05 B2AUX DW 0000 ;auxiliary type
07 B2STYP DB 00 ;storage type
08 B2FSIZ DW 0000 ;size of file in 512-byte blocks
0A B2MODDAT DW 0000 ;date of modification
0C B2MODTIM DW 0000 ;time of modification
0E B2CRDAT DW 0000 ;date of creation
10 B2CRTIM DW 0000 ;time of creation
12 B2ID3 DB 2 ;ID byte
13 DS 1 ;reserved
14 B2EOF HEX 000000 ;end-of-file (EOF) position
17 B2FLN DB 00 ;length of filename or partial pathname
18 B2FNAM DS 15 ;ASCII filename or partial pathname
;If the filename is a partial pathname
;it will overwrite the following
;2 segments for native filename
27 B2NFLN DB 00 ;length of native filename]
28 B2NFNAM DS 48 ;ASCII native filename
58 DS 23 ;reserved, must be zero
6F B2GSACS DB 00 ;GS/OS access code (high byte)
70 B2GSFTYP DB 00 ;GS/OS file type code (high byte)
71 B2GSSTYP DB 00 ;GS/OS storage type code (high byte)
72 B2GSSIZ DW 0000 ;GS/OS size of file in blocks (high word)
74 B2GSEOF DB 00 ;GS/OS EOF position (high byte)
75 B2DSKSPC HEX 00000000 ;disk space needed (512 byte Blocks)
79 B2OS DB 00 ;operating system type












Page 4


OPERATING SYSTEM TYPE

VALUE DESCRIPTION VALUE DESCRIPTION
----- -------------------------- ----- ------------------------
00 ProDOS or SOS 07 Macintosh XL
01 DOS 3 08 Apple CP/M
02 reserved 09 reserved
03 DOS 3.2 or DOS 3.1 0A MS-DOS
04 Apple II Pascal 0B High Sierra(CD-ROM)
05 Macintosh MFS 0C ISO 9660 (CD-ROM)
06 Macintosh HFS

7A B2NFTYP DW 0000 ;native file type code
7C B2PHANTOM DB 00 ;phantom file flag

PHANTOM FILE S/W DESIGNATIONS

VALUE DESCRIPTION VALUE DESCRIPTION
----- -------------------------- ----- ------------------------
00 [generic] 04 Modem MGR
01 Point-to-Point 05 CommWorks
02 Tele-Master Comm Sys 06 MouseTalk
03 ProTERM

7D B2FLAGS DB 00 ;data flags

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
B2FLAGS 7 data is compressed (SQUeezed)
6 data is encrypted
0 file is sparse/packed


NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
SQUEEZED Huffman Squeeze. The filename will have '.QQ'
appended. The first 16 bytes of the file are
the original filename length and filename, the
next 14 bytes are identical in form and content
to the Apple GetInfo results and the bytes $3 -
$10 of the Binary ][ header. The rest of the
file is squeezed with packing.

7E B2VERSION DB 00 ;Binary II version number
7F B2NUMFOL DB 00 ;number of files to follow


NOTE : Many GS/OS file attributes are stored in 2 places (this is a result
of the differences between ProDOS 8/16 and GS/OS).

POSITIONING IN FILE
-------------------

Begining of File Data = Begining of File Header + $80

Next File Header = Begining of File Header + $80 + B2FSIZ
or
= Begining of File Data + B2FSIZ

**************************************************


DWC Page 5
===

System of Origin : IBM

FILE FORMAT
-----------

file 1
file 2
.
.
file n
file header 1
file header 2
.
.
file header n
end header
EOF


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 DWCFNT DS 12 ;filename
0C DB 00
0D DWCOSZ HEX 00000000 ;Uncompressed size
11 DWCTIM DW 0000 ;File time ala MSDOS
13 DWCDAT DW 0000 ;File date ala MSDOS
15 DWZNSZ HEX 00000000 ;Compressed size
19 DWCFTP HEX 00000000 ;File offset from SOF
1D DWCMTD DB 00 ;Method
1E DW 0000 ;???
20 DWCCRC DW 0000 ;CRC


END HEADER
----------

ORG DWCEND-27

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 DS 20 ;?
14 DW 0000 ;Number of files
16 DW 0000
18 ASC 'DWC' ;ID
1B DWCEND


COMPRESSION METHOD
------------------

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
Stored No compression used
Crunched Packing, LZW, 4K buffer, var len (9-12 bits)

**************************************************




GIF Page 6
---

Created by Compuserve, Inc.

FILE FORMAT
-----------

GIF Header
Global Color Map
Image Descriptor 1
Local Color Map
Raster Data
Image Descriptor 2
Local Color Map
Raster Data
.
.
.
Image Descriptor n
Local Color Map
Raster Data
GIF Terminator
EOF


HEADER FORMAT
-------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 GIFSIG ASC 'GIF87a' ;Gif signature and version (87a)
06 GIFWDTH DW 0000 ;Screen Width - Raster width in pixels
08 GIFHGHT DW 0000 ;Screen Height - Raster height in pixels
0A GIFCOLR DB 00 ;Colorbyte

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
GCMFLG 7 if set - Global color map follows Descriptor
GCMRES 6-4 # bits of color resolution + 1
3 reserved
GCMPSIZ 2-0 # bits/pixel in image +1, range of values 1
to 8 bits. This gives a range of 2 (B & W) to
256 colors

0B GIFBKGRND DB 00 ;Color index of screen background,
;color is defined from the Global
;color map or default map.
GIFEXTN ;Currently undefined GIF extension
;block

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ---------- ----------------------------
00 GIFEXTSIG DB $21 ;Extension Block signature
01 EXTCODE DB 00 ;Extension Function Code
02 EXTCNT0 DB 00 ;Count of function bytes
03 EXTFUNC0 DS up to 255
.
. repeat EXTCNT0 and EXTFUNC0 as many times as required
.
EXTTERM DB 00 ;Termination of Extension Block

0C GIFHEND DB 00 ;end of GIF header



Page 7


GLOBAL COLOR MAP FORMAT
-----------------------

GCMNUM = 2 ^ (GCMPSIZ)

GCMLEN = GCMNUM * 3

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 GCMCOLR0 HEX 000000 ;definition for color 0

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ---------- ----------------------------
00 REDINTNS DB 00 ;Red intensity value for this
;color
01 GRNINTNS DB 00 ;Green intensity value for
;this color
02 BLUINTNS DB 00 ;Blue intensity value for this
;color

03 GCMCOLR1 HEX 000000 ;definition for color 1
.
.
.
xx GCMCOLRn HEX 000000 ;definition for color n


IMAGE DESCRIPTOR
----------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 IMGSEP DB $2C ;Image separator character
01 IMGLFT DW 0000 ;Start of image in pixels from the
;left side of the screen
03 IMGTOP DW 0000 ;Start of image in pixels from the
;top of the screen
05 IMGWID DW 0000 ;Width of the image in pixels
07 IMGHGT DW 0000 ;Height of the image in pixels
09 IMGFLGS DB 00 ;GIF flags for this image

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
MAPFLG 7 If set, use pixel and Local color map
following, use pixel; otherwise use Global
Color Map
RASTFLG 6 If clear, Image formatted in Sequential order,
if set then Image in Interlaced order
5-3 unused
IMGPSIZ 2-0 bits per pixel for this image

0A LOCOLMAP DS [IMGPSIZ^2]*3 ;Same format and size computation
;as Global Color Map
RASTDAT ;Raster Data - compressed image
GIFTERM DB $3B ;Termination of GIF data

COMPRESSION METHOD
------------------
LZW, 4k BuffER, variable length (3-12 bits)

**************************************************


LZH Page 8
===

System of Origin : IBM

FILE FORMAT
-----------

file header 1
file 1
file header 2
file 2
.
.
file header n
file n
EOF


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 LZHHSZ DB 0 ;Header size
01 LZHCKS DB 0 ;Cksum of remaining bytes
02 LZHMTD ASC '-lh0-' ;Method
07 LZHNSZ HEX 00000000 ;Compressed size
0B LZHOSZ HEX 00000000 ;Uncompressed size
0F LZHTIM DW 0000 ;File time (MSDOS)
11 LZHDAT DW 0000 ;File date (MSDOS)
13 LZHATR DW 0000 ;File attribute
15 LZHFNL DB 00 ;filename/path length
16 LZHFNT DS LZHFNL ;filename/path
2B LZHCRC DW 0000 ;CRC-16


COMPRESSION METHOD
------------------

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
STORED -lh0- No compression used
LZHUF -lh1- LZW, 4K buffer, Huffman for upper 6 bits of pos
LZARI -lz4- LZW, Arithmetic Encoding
LZARI -lz5- LZW, Arithmetic Encoding


POSITIONING IN FILE
-------------------

Begining of File Data = Begining of Header + LZHHSZ

Begining of Next File Header = Begining of File Data + LZHNSZ

**************************************************










NuFX - SHRINKIT Page 9
===============

System of Origin: Apple ][

Original author: Andrew Nicholas

FILE FORMAT
-----------

Master Header
File 1 Header
Attribute Section
Filename Section
Thread Section
Thread 1
. File data is contained in a thread
.
Thread n
File 2 Header
Attribute Section
Filename Section
Thread Section
Thread 1
.
.
Thread n
File 3 Header
.
.
.
EOF


MASTER HEADER
-------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 NUID1 HEX 4EF546E96CE5 ;Master signature spells "NuFile"
;in alternating high and low ASCII
06 NUCRC DW 0000 ;CRC of bytes $08 - $2F in this block
08 NURECS HEX 00000000 ;Total number of files in this archive
0C NUCRTIM HEX 000000 ;archive creation time and date
0F NUCRDAT HEX 0000000000
14 NUMDTIM HEX 000000 ;time and date archive last modified
17 NUMDDAT HEX 0000000000
1C DS 19 ;reserved
2F ;end master header

















Page 10

TIME FORMAT
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ---------- ----------------------------
00 GSSEC DB 00 ;second - 0 through 59
01 GSMIN DB 00 ;minute - 0 through 59
02 GSHR DB 00 ;hour - 0 through 23
03 GSYR DB 00 ;current Year minus 1900
04 GSDAY DB 00 ;day - 0 through 30
05 GSMNTH DB 00 ;month - 0 through 11, with
;0=January
06 DB 00 ;filler byte - reserved = 00
07 GSWDAY DB 00 ;weekday - 1 through 7, with
;1=Sunday

The format of this field is identical to that described in the
_ReadTimeHex ($0D03) call described on page 14-14 of the
Apple_IIgs_Toolbox_Reference:_Volume_1.


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 NXID1 HEX 4EF546D8 ;Header signature spells "NuFX" in
;alternating high and low ASCII
04 NXCRC DW 0000 ;CRC of bytes $06 - NXATRBCNT+1


ATTRIBUTE SECTION
-----------------

06 NXATRBCNT DW 0000 ;length of the attribute section of
;each header. The distance from NXID1
;to and including NXFNL
08 NXVERS DW 0000 ;Minimum version needed for extraction
0A NXNUMTHR HEX 00000000 ;The number of threads following NXFNAM
0E NXSYSID DW 0000 ;Native file system identifier

SYSTEM IDENTIFIERS

VALUE DESCRIPTION VALUE DESCRIPTION
----- -------------------------- ----- ------------------------
0000 File is an Archived Disk 0008 Apple CP/M
0001 ProDOS/SOS 0009 reserved, do not use
0002 DOS 3.3 000A MS-DOS
0003 DOS 3.2 000B High-Sierra/ISO 9660
0004 Apple II Pascal 000C
0005 Macintosh(tm) (HFS) . reserved
0006 Macintosh (MFS) FFFF
0007 LISA(tm) file system


10 NXSYSSEP ASC '/' ;Native file system seperator
;ProDOS = '/' ($2F)
;HFS = ':' ($3A)
;MS-DOS = '\' ($5C)
11 NXSPARSE DB 00 ;sparse file indicated if = $01
12 NXACCESS HEX 00000000 ;



Page 11


LABEL BIT DESCRIPTION if set
----------- --------- -----------------------------------------
NXACCESS 31-8 reserved, must be zero
7 destroy enabled
6 rename enabled
5 backup needed
4-3 reserved, must be zero
2 file is invisible
1 write enabled
0 read enabled

16 NXFTYP HEX 00000000 ;file type, Disk = 0
1A NXEXTYP HEX 00000000 ;extra type, ProDOS aux_type or HFS
;creator_type, Disk: total number
;of blocks on the device
1E NXSTRTYP DW 0000 ;storage type, if a disk this should
;contain the block size of the O/S

STORAGE TYPE

TYPE IF FILE SIZE IS: O/S BLOCK SIZE
---- ------------------------- --------- ---------------
$1 < 512 bytes ProDOS 512
$2 > 511 bytes, < 128k DOS 3.3 256
$3 > 129k HFS 524
$5 extended file
$D subdirectory

20 NXCRTIM HEX 000000 ;file creation time and date
23 NXCRDAT HEX 0000000000
28 NXMDTIM HEX 000000 ;time and date file last modified
2B NXMDDAT HEX 0000000000
30 NXARCTIM HEX 000000 ;time and date file archived
33 NXARCDAT HEX 0000000000
.
.

Any other attributes are added here. NXATRBCNT points to the NXFNL, which
is always the last attribute.

.
.
NXATRBCNT-2
NXFNL DW 0000 ;filename length


FILENAME SECTION
----------------

NXFNL+2
NXFILE DS NXFNL ;Filename, partial pathname or disk
;volume name. Names ported across
;systems may have illegal characters
;or characteristics.









Page 12


THREAD SECTION
--------------

Thread records are 16 byte records which immediately follow the filename and
describe the types of data structures which are included with a given record.
The number of threads is in the attribute section under NXNUMTHR.


A thread record can be represented as follows:

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 THRCLASS DW 0000 ;describes the class of the thread

0000 CLS_MSG
0001 CLS__CNTRL
0002 CLS_DATA
0003 CLS_SPRSE

02 THRFRMT DW 0000 ;format of the data within the thread

0000 ;Uncompressed
0001 ;SQueezed (SQ/USQ)
0002 ;Dynamic LZW [ShrinkIt]
0003
. ;RESERVED, contact the author
FFFF

04 THRKIND DW 0000 ;describes data in thread

if THRCLS = and THRKIND = THEN THE THREAD CONTAINS:
---------------- -------------- ---------------------------
CLS_MSG 0000 ASCII text
all others undefined

CLS_CNTRL 0000 create directory
all others undefined

CLS_DATA 0000 data_fork of file
0001 disk image
0002 resource_fork of file
all others undefined

06 DS 2
08 THREOF HEX 00000000 ;length of the uncompressed thread
0C THRCMPEOF HEX 00000000 ;length of the compressed thread

POSITIONING IN FILE
-------------------

Start of the thread list = (beginning of header) + NXATRBCNT + NXFNL

End of the thread list = (beginning of header) + NXATRBCNT + NXFNL +
(16 * NXNUMTHR)

Start of a data_thread = (beginning of header) + NXATRBCNT + NXFNL +
(16 * NXNUMTHR) + (THRCMPEOF of all threads
in the thread list which are not data prior
to finding a CLS_DATA = 0000)




Page 13


Start of a resource_thread = (beginning of header) + NXATRBCNT + NXFNL +
(16 * NXNUMTHR) + (THRCMPEOF of all the
threads in the thread list which are not
resources prior to finding a
CLS_DATA = 0002)

Next record = (beginning of header) + NXATRBCNT + NXFNL +
(16 * NXNUMTHR) + (THRCMPEOF of each thread)

**************************************************


PACKIT
======

System of Origin : Macintosh

FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 PITFLN HEX 00 ;filename length
01 PITFNAM DS 63 ;filename
40 PITTYP HEX 00000000 ;file type
44 PITCRT HEX 00000000 ;Creator
48 PITFFLG DW 0000 ;Finder flags
4C PITLOK DW 0000 ;locked?
4E PITDSIZ HEX 00000000 ;data fork uncompressed size
52 PITRSIZ HEX 00000000 ;resource fork uncompressed size
56 PITCDSIZ HEX 00000000 ;data fork compressed size
5A PITCRSIZ HEX 00000000 ;resource fork compressed size
5E PITCRC DW 0000 ;CRC

**************************************************


STUFFIT
=======

System of Origin : Macintosh

Original author : Raymond Lau

FILE FORMAT
-----------

Master Header
file header 1
file 1 resource fork
file 1 data fork
file header 2
file 2 resource fork
file 2 data fork
.
.
file header n
file n resource fork
file n data fork
EOF



Page 14


MASTER HEADER
-------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 SITHSIG ASC 'SIT!' ;STUFFIT archive signature
04 SITHNUM DW 0000 ;number of files in archive
06 SITHLEN HEX 00000000 ;length of entire archive incl hdr
0A SITHID2 ASC 'rLau' ;authors name - R. Lau
0E SITHVER DB 00 ;version number
0F DS 7 ;reserved


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 SITFRCMP DB 00 ;rsrc fork compression method
01 SITFDCMP DB 00 ;data fork compression method
02 SITFNL DB 00 ;file name length
03 SITFNAM DS $3F ;filename
41 SITFTYP HEX 00000000 ;filetype
45 SITFCR HEX 00000000 ;file creator
49 SITFFFL DW 0000 ;Finder flags
4B SITFCRD HEX 00000000 ;creation date
4F SITFMDD HEX 00000000 ;modification date
53 SITFRLN HEX 00000000 ;uncompressed resource fork length
57 SITFDLN HEX 00000000 ;uncompressed data fork length
5B SITFCRLN HEX 00000000 ;compressed resource fork length
5F SITFCDLN HEX 00000000 ;compressed data fork length
61 SITFRCRC DW 0000 ;resource fork CRC
63 SITFDCRC DW 0000 ;data fork CRC
65 SITFRPAD DB 00 ;pad bytes for encrypted files,
66 SITFDPAD DB 00 ;resource and data forks
6A DS 4 ;reserved
6E SITFHCRC DW 0000 ;CRC of file header


STUFFIT METHODS

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
noComp 0 uncompressed
rleComp 1 RLE compression
lzwComp 2 LZW compression, 18k buffer, 14 bit code size
hufComp 3 Huffman compression
encrypted 16 bit set if encrypted. ex: encrypted+lzwComp
startFolder 32 marks start of a new folder
endFolder 33 marks end of the last folder started













Page 15


POSITIONING IN FILE
-------------------

First File Header = SITHSIG + $15

Begining of Resource Fork = SITFRCMP + $6F

Begining of Data Fork = Begining of Resource Fork + SITFCRLN

Next File Header = Begining of previous Data Fork + SITFCDLN
or
= Previous File Header + $6F + SITFCRLN + SITCDLN

**************************************************


ZIP
===

System of Origin : IBM

Original author : Phil Katz

FILE FORMAT
-----------


Files stored in arbitrary order. Large zipfiles can span multiple
diskette media.

Local File Header 1
file 1 extra field
file 1 comment
file data 1
Local File Header 2
file 2 extra field
file 2 comment
file data 2
.
.
.
Local File Header n
file n extra field
file n comment
file data n
Central Directory
central extra field
central comment
End of Central Directory
end comment
EOF












Page 16


LOCAL FILE HEADER
-----------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 ZIPLOCSIG HEX 04034B50 ;Local File Header Signature
04 ZIPVER DW 0000 ;Version needed to extract
06 ZIPGENFLG DW 0000 ;General purpose bit flag
08 ZIPMTHD DW 0000 ;Compression method
0A ZIPTIME DW 0000 ;Last mod file time (MS-DOS)
0C ZIPDATE DW 0000 ;Last mod file date (MS-DOS)
0E ZIPCRC HEX 00000000 ;CRC-32
12 ZIPSIZE HEX 00000000 ;Compressed size
16 ZIPUNCMP HEX 00000000 ;Uncompressed size
1A ZIPFNLN DW 0000 ;Filename length
1C ZIPXTRALN DW 0000 ;Extra field length
1E ZIPNAME DS ZIPFNLN ;filename
-- ZIPXTRA DS ZIPXTRALN ;extra field

CENTRAL DIRECTORY STRUCTURE
---------------------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 ZIPCENSIG HEX 02014B50 ;Central file header signature
04 ZIPCVER DB 00 ;Version made by
05 ZIPCOS DB 00 ;Host operating system
06 ZIPCVXT DB 00 ;Version needed to extract
07 ZIPCEXOS DB 00 ;O/S of version needed for extraction
08 ZIPCFLG DW 0000 ;General purpose bit flag
0A ZIPCMTHD DW 0000 ;Compression method
0C ZIPCTIM DW 0000 ;Last mod file time (MS-DOS)
0E ZIPCDAT DW 0000 ;Last mod file date (MS-DOS)
10 ZIPCCRC HEX 00000000 ;CRC-32
14 ZIPCSIZ HEX 00000000 ;Compressed size
18 ZIPCUNC HEX 00000000 ;Uncompressed size
1C ZIPCFNL DW 0000 ;Filename length
1E ZIPCXTL DW 0000 ;Extra field length
20 ZIPCCML DW 0000 ;File comment length
22 ZIPDSK DW 0000 ;Disk number start
24 ZIPINT DW 0000 ;Internal file attributes

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
ZIPINT 0 if = 1, file is apparently an ASCII or
text file
0 if = 0, file apparently contains binary
data
1-7 unused in version 1.0.

26 ZIPEXT HEX 00000000 ;External file attributes, host
;system dependent
2A ZIPOFST HEX 00000000 ;Relative offset of local header
;from the start of the first disk
;on which this file appears
2E ZIPCFN DS ZIPCFNL ;Filename or path - should not
;contain a drive or device letter,
;or a leading slash. All slashes
;should be forward slashes '/'
-- ZIPCXTR DS ZIPCXTL ;extra field
-- ZIPCOM DS ZIPCCML ;file comment


Page 17


END OF CENTRAL DIR STRUCTURE
----------------------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 ZIPESIG HEX 06064B50 ;End of central dir signature
04 ZIPEDSK DW 0000 ;Number of this disk
06 ZIPECEN DW 0000 ;Number of disk with start central dir
08 ZIPENUM DW 0000 ;Total number of entries in central dir
;on this disk
0A ZIPECENN DW 0000 ;total number entries in central dir
0C ZIPECSZ HEX 00000000 ;Size of the central directory
10 ZIPEOFST HEX 00000000 ;Offset of start of central directory
;with respect to the starting disk
;number
14 ZIPECOML DW 0000 ;zipfile comment length
16 ZIPECOM DS ZIPECOML ;zipfile comment


ZIP VALUES LEGEND
-----------------

HOST O/S

VALUE DESCRIPTION VALUE DESCRIPTION
----- -------------------------- ----- ------------------------
0 MS-DOS and OS/2 (FAT) 5 Atari ST
1 Amiga 6 OS/2 1.2 extended file sys
2 VMS 7 Macintosh
3 *nix 8 thru
4 VM/CMS 255 unused


GENERAL PURPOSE BIT FLAG

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
ZIPGENFLG 0 If set, file is encrypted
or 1 If file Imploded and this bit is set, 8K
ZIPCFLG sliding dictionary was used. If clear, 4K
sliding dictionary was used.
2 If file Imploded and this bit is set, 3
Shannon-Fano trees were used. If clear, 2
Shannon-Fano trees were used.
3-4 unused
5-7 used internaly by ZIP

Note: Bits 1 and 2 are undefined if the compression method is
other than type 6 (Imploding).














Page 18


COMPRESSION METHOD

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
Stored 0 No compression used
Shrunk 1 LZW, 8K buffer, 9-13 bits with partial clearing
Reduced-1 2 Probalistic compression, L(X) = lower 7 bits
Reduced-2 3 Probalistic compression, L(X) = lower 6 bits
Reduced-3 4 Probalistic compression, L(X) = lower 5 bits
Reduced-4 5 Probalistic compression, L(X) = lower 4 bits
Imploded 6 2 Shanno-Fano trees, 4K sliding dictionary
Imploded 7 3 Shanno-Fano trees, 4K sliding dictionary
Imploded 8 2 Shanno-Fano trees, 8K sliding dictionary
Imploded 9 3 Shanno-Fano trees, 8K sliding dictionary


EXTRA FIELD

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ---------- ----------------------------
00 EX1ID DW 0000 ;0-31 reserved by PKWARE
02 EX1LN DW 0000
04 EX1DAT DS EX1LN ;Specific data for individual
. ;files. Data field should begin
. ;with a s/w specific unique ID
EX1LN+4
EXnID DW 0000
EXnLN DW 0000
EXnDAT DS EXnLN ;entire header may not exceed 64k

**************************************************


ZOO
===

System of Origin : IBM

Original author : Rahul Dhesi

FILE FORMAT
-----------

Master Header
file 1 header
file 1
file 2 header
file 2
.
.
file n header
file n
EOF










Page 19


MASTER HEADER
-------------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 DS 20
14 ZOOSIG HEX A7DCFDC4 ;File signature
18 ZOO1PTR HEX 00000000 ;pointer to 1st header
1C ZOO? HEX 00000000 ;?
20 ZOOMVER DB 00 ;version making archive
21 ZOOMIN DB 00 ;minimum version needed to extract


FILE HEADER
-----------

OFFSET LABEL TYP VALUE DESCRIPTION
------ ----------- ---- ----------- ----------------------------------
00 ZOOFSIG HEX A7DCFDC4 ;signature
04 ZOOFTYP DB 00 ;?
06 ZOOFCMP DB 00 ;Compression method
08 ZOOFNXH HEX 00000000 ;Nxt hdr ofst frm Start of ZOO file
0A ZOOFCUR HEX 00000000 ;Offset of this hdr
0E ZOOFDAT DW 0000 ;Last mod file date (MS-DOS)
10 ZOOFTIM DW 0000 ;Last mod file time (MS-DOS)
12 ZOOFCRC DW 0000 ;CRC-16
14 ZOOFOSZ HEX 00000000 ;Uncompressed size
18 ZOOFNSZ HEX 00000000 ;Compressed size
1C ZOOFMVER DB 00 ;version that made this file
1D ZOOFMIN DB 00 ;minimum version needed to extract
1E Z00FDEL DB 00 ;1 if file deleted from archive
1F ZOOFCMTP HEX 00000000 ;pointer to comment, 0 if none
23 ZOOFCMTL DW 0000 ;length of comment
25 ZOOFNAM DS 13 ;filename


ZOO METHOD
----------

NAME METHOD DESCRIPTION
----------- ------ --------------------------------------------
Stored No compression used
Crunched Packing, LZW, 4K buffer, var len (9-12 bits)

POSITIONING IN FILE
-------------------

Begining of 1st File header = Begining of File + ZOO1PTR
or
= Begining of File + $21

Begining of File Data = Begining of File Header + $31

Begining of Next File = Begining of File + ZOOFNXH

Begining of File Comment = Begining of File Header + ZOOFCMTP

**************************************************





Page 20


TIME VALUES
===========

MS-DOS TIME FORMAT
------------------

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
DATE 15-9 Year
8-5 Month
4-0 Day (all zeroes means no date)

TIME 15-11 Hours (military)
10-5 Minutes
4-0 Seconds


ProDOS/SOS TIME FORMAT (APPLE)
------------------------------

LABEL BIT DESCRIPTION
----------- --------- -----------------------------------------
DATE 15-9 Year (0-99)
8-5 Month
4-0 Day

TIME 15-8 Hour (military time)
7-0 Minutes

**************************************************


EXTENDED FILES
--------------

Extended files are a storage format used by a variety of operating
systems. The filename information points to a file that points to 2 other
files known as the DATA FORK and the RESOURCE FORK.

The resource fork contains information about, and/or for the use of, the
data fork. In porting amongst systems the resource fork is probably of
no use.

The data fork contains the actual file.

**************************************************


FILENAMES
---------

File name lengths, legal characters and format vary amongst the various
operating systems. MS-DOS allows a wider variety of characters while the
Apple operating systems allow longer names with no set format (no
extensions). Any program must be ready to convert a filename into the
current operating system format as well as handle any paths (either by
creating or ignoring them).






Page 21


A suggestion would be to use a more universal standard for the filenames
of files that are likely to be ported (ie; Text, ASCII Source, GIF, ASCII
data files, etc) while making no special effort with executable code
(including tokenized BASIC) filenames.

Such a standard might be:

a filename of no more than 13 or less than 6 characters
legal characters A-Z (all uppercase) the '.' and 0-9
periods to be used only once in a file to make an MS-DOS
type extension (ie; .TXT, .DOC, etc)
the filename MUST start with an alphabetic character (A-Z)

**********************************************************************


Information taken from files by Alex Bamdad, Rahul Dhesi, Jim Dorsey, Don
Elton, Colin James, Phil Katz, Raymond Lau, Gary Little, Andrew Nicholas,
Haruhiko Okumura, Martin Peckham, Mike Sax, Tim Swihart and probably
others.




 December 9, 2017  Add comments

Leave a Reply