The Datafile PD-CD 5/DATAFILE_PDCD5.iso/utilities/g/gzip/!gzip/!Help

PGP Message | 1995-06-29 | 12.0 KB | 229 lines

-----BEGIN PGP SIGNED MESSAGE-----

!Gzip (0.40) 29-Jul-1993
- ------------------------
A front end for GNUzip, taken from "!Cruncher" .
Please read the docs.!help file first to understand how the
frontend (!Cruncher) originally worked.
Features:

* VERSION 0.20 *

- - Compression hardness factor selectable in menu (for gzip)

- - noDMA ,if selected ,turns off video DMA during de/compressing

- - Crunch / Decrunch / Reverse , this sets the mode for what's
  beeing done with the files dropped on the iconbar icon,
  (directory dropping works through the directory recursively)

- - Filetype for GZIP (generally the RISCOS variant of the .gz suffix of GNUzip)
  is 003 (Cruncher is 000) , 003 seemed free to me,never saw it anywhere.
  This might be replaced sooner or later if someone at Acorn realizes that
  there is a need for a gzip filetype.I dunno how to apply.

- - A copy of gzip is in the directory, LEAVE it there, but you can copy it
  elsewhere (into your library) and use it on the CLI as well.Note that
  this port of GZIP 1.0.7 does not support filetyping of the result in
  any form, this is what !gzip does.
  A new port of gzip 1.1.1 is about to roll out.

- - this port of gzip has problems with certain filenames/paths,namely with
  xxxx/yyy filenames, e.g. with a slash, that is interpreted as the
  separator character. This is due to the fact that gzip has been compiled
  under unixlib. I still search a way to turn that automatic file conversion
  off. This type of filename,that contains a '/' ANYWHERE IN IT'S ENTIRE
  FULL PATH is ignored,a beep is made upon hitting such a file,thus it will not
  stop the de/compressing of a selection of files.

- - !gzip uses the Wimp$Scrapdir to hold uncompressed/compressed files temporarily,
  which means that the device your !Scrap resides on,must have sufficient
  free space. !Cruncher uses RAM (always), with !gzip it all depends on which
  of your !Scrap 's you've double clicked last (or the filer has seen first),
  so to speed it all up and have it work like !Cruncher,you use a !Scrap in
  your RAM, if you run low on memory (or have bigger-than-memory files to
  comress) use a !Scrap on your harddisc,even a floppy will do.
  An attempt is made to verify that there is enough space on the !Scrap device
  as well as the final destination.

- - The front end does it's best not to ruin the precious file,but it might
  come up with an ugly error screen (if you have DMA off,press space once
  in a while,if you think an error has occured), then recover with an
  audible beep.

- - !gzip makes educated guesses about the free space on the filing systems used
  by !Scrap and the final result (un/gzipped file). There is a small chance
  that a file can get lost during ungzipping (because it's a guess) .This occurs
  when the ungzipped file is more than 4 times it's compressed counterpart AND
  the !Scrap device run's full during processing. I found no way to execute an
  external program (gzip) and not using WimpStartTask, and I cannot detect errors
  that occur during a run of the external program,at least not,when it
  produces some output; I can't know whether the output file is corrupted
  or too short (this is the case when the !Scrap device runs full). This problem
  will disappear with a new port of gzip,that recovers from errors like 'disc full'
  and deletes it's (certainly) too short output file.

* VERSION 0.21 *

*LAST minute changes, a few hours after release* so we have version 0.21 *grrrrr*

- - fixed stupid bug : gzip wouldn't accept '>' or '<' in a filename either - ignoring now.
  I really need to compile a gzip without name conversion.
- - gzip wants 480k of memory to run (that's the safe minimum), so it now CHECKS
  that it really can get these,anytime before the real gzip is called up.
  Sets Wimp_SlotSize to 480k before calling gzip.
- - fixed bad add_memory bug in (not mine!) library, now altering WimpSlot doesn't
  give the ram to the task forever,because the really-gained-length was never returned,
  so upon freeing it,a 'free 0 bytes' routine ran. !Crunch will benefit from this fix,
  too.
- - while gzip'ing I had a few fatal crashs, it looked like my HCCS podule fucked up gain,
  but nevertheless: these errors occurred with !Scrap being in RAM: . So be careful.
  I added the 480k memory check since then,so I am not sure if it was just low memory.

* VERSION 0.30 *

- - new gzip 1.1.1 is used now. No more problems with path/filenames and
  separators, so you can use path/filenames that contain < > and / ,too,now!
- - enhanced 'enough space free on device?' testing,for both RiscOS 2 and 3,
  as well as for MemFS (this one is not perfect,yet,somehow).
- - increased Wimpslot to 64k ,which I am still not sure about. Was having
  'nested procedures/functions' when using a WimpSlot of 32k.
- - a double click on a gzip-filetyped file now gunzips that file !!!
  (!gzip must be loaded)
- - files under 128 byte length are no longer tried for comression,it just doesn't
  make any sense,because it doesn't save you any diskspace !
- - compression ratios must archive at least 95% (5% gain),or the file will be left
  uncompressed. Otherwise you end up compressing several MB with very high
  effort (time/cpupower) and it gains you nearly nothing. ZIP files that are
  gzipped with a -9 factor fall in that 5% range (!),so virtually every other file
  type except compressed .Z or .ARJ are compressed better than just 5% gain.
- - Brushed code up a bit,made ready for future enhancements.
- - corrected usage of HourGlass ; discovered that the WIMP sometimes does SOMETHING
  after a file has been de-/compressed (turns on Hourglass,updates filer window(s)),
  I didn't yet find out why,but it is related to the number of open windows/shown
  sprites/Apps.
- - bug fix: couldn't open menu for more than 64 times (orignal bug from !Cruncher !)
  (no kill_window upon iconbar_mouse_click, kept filling up window list)
  Searched 3 hours for this sucker.
- - Had to change filetype for gzip'ed files from 003 to 020hex . 003 was already used
  in !ArmSI (benchmarks) as the result save file.
- - If !Scrap and the processed file reside on the same disk, *rename is used instead of
  *copy to move the resulting file to it's place.Speeds up things considerably,so
  if you do ALOT of g/un/zipping,you better copy a !scrap onto the device (harddisc
  only,I say) and doubleclick it.

* VERSION 0.40 *

- - bugfix: double click on gzip'ed file wouldn't gunzip it,if option 'Crunch' was set,
  rather than 'DeCrunch' or 'Reverse'. As always: the bug was spotted 5 mins after
  release of version 0.30 on the Stuttgart server.
- - re-org of menu structure. Crunch/Decrunch/Reverse is no Action->pack/unpack/reverse
  chosing the desired packer happens with the Method->gzip/compress/cruncher menu.
- - Factor->1 fast ... 9 best choses the goodness factor for gzip (only) now.
- - There seems to be a bad bug in Wimp_lib: it seems impossible to do nested menu's,
  otherwise ,I would have put the Factor-> menu behind the Method->Gzip entry.
  No ambition to hunt this one down,right now.
- - we do !Crunched files again. Yeah.
  BUT:double click on a filetype 000 (cruncher) file produces a strange reaction with DDE
  tools,by inserting that file as an icon entry. No cure yet.So double click on Crunched
  (type 000) files will not have the desired effect,when you run a DDE tool.
- - we do unix compressed files. Yeah!
  But: compress handles stdin/out for itself,so fucks up on < and > in filenames.
  An attempt is made to use !Scrap to compensate this.The medium where !Scrap resides
  must have enough space to hold the original file twice,and must itself have a full
  path without any < or > .Otherwise the file is skipped/ignored.
- - when data_load is received, program checks if that file/dir really exists, suppressing
  the mysterious filetype 000 data_load request,that happens sometimes on my machine
- - turn off ESC while doing vital operations. That won't stop gunzip receiving/reacting
  to a SIG_INT signal,though.Maybe recompile gzip with all trap handlers doing zilch()
  At least no files get mangled anymore,when pressing ESC, maybe an open file here or
  there (courtesy of gzip) ,but who said you couldn't enter *close ?


* NEXT VERSION (:-) *

- - Hmm. UnArj ? not enough. Na...I begged Robert Jung for so long already....
- - Acorn's squash ? I heard a few bad stories about it,but basically !Squash is nothing
  but Acorn's version of !Cruncher (hehe).
- - I guess bugfixes will be enough for the next version.
- - fix the bug in Wimp_lib to have nested menus
- - protect the OSCLI commands from diskerrors,like stupid users trashing their files by
  removing the disk during operation,or occasional errors during read/write on my HD.
- - Version 1.00 . We have arrived,we have arrived!


* COPYLEFT *

- - This program is (c)1993 by me, released under the GNU public license,
  and for all those who can't read or never read it: The NO WARRANTY terms do appply.
  (This sentence (until the first comma) is probably the shortest
   no-responsibility-for-anything-disclaimer that any author for Archimedes software
   ever came up with (:-))

- - other (C)left:
 -ACE- ArcAngels didn't have any phrases on (c)right,so I assumed PD under the terms
  of the GNU public licens- how convenient, thanks for the front end, d00ds !
 -Thanks go to John Kortink for the LZW/LZWD modules,as the modules are finally
  included in this release (:-).

Have fun,because packers are only best with a front end,on the Arc !

Kai Schlichting
[e-mail] [The Mindvox system 1-212-989-1550 v32bis, telnet phantom.com]
[e-mail] [acorn ftp admin] (talk accepted)
[e-mail] [University] (talk accepted)

Phone number: those whom I want to know,know it anyway
Address: You kidding ? I am _living_ virtually !


* CREDITS * * DISCREDITS *

Useful tools during work - credits go to:
 !Zap 0.90 by Dominic Symes, a great editor
 !StrongEd 1.20 - Guttorm, I hate your BASIC functions ,but love your ListOfFunction !
 !PRM_Index - Martin Wuertner's front end for a PRM index
 !PGP/wimp - I sign with those...
 Jolanta - my dearest gf , never distracts me from work (:-)  _
 Phantom Access Inc. - NYC,NY - without you guys from the 3|_1|3 |_0|> |-|a[|<3R
                       Unification Church little would be possible, r00l tha w0r|_|> .

 Compu$pend ,Fraudigy and America Offline : Civil Liberties and free speech ? No !
                         Censorship - YES !
 Kolja and Jo - at the other end of the long line. Thanks for the 4.5m SCSI cable,d00d!
 Torsten - for 'intel outside' stickers, and being a cool d00d for 7 straight years.
 The old boyz club - you know who you are. Flensburg,April 91 party !
 Erik B - you hold the axe now, use it. And no mercy.
 Kim Clancy - for her courage. I'll never buy a Washington Post again.
 Valencia - for making great frozen orange juice that serves well at 4 am (:-)
 Chesapeake and Potomac Telephone co.- for making the right connection into the
                         Internet,up to 20 hours a day (:-) !
 Safeway food stores Inc. for the endless supply of marshmellows and donuts
      and fungy laden pizza and bread.
 The local mail advertisement business - for the constant flood of junk into my mailbox.
 VA Power for their great outages every few weeks. I love lost files.
 CompUSA for the UPS/protector, soon to be bought.
         Microsoft distributes their new NT warez _officially_ over pirate BBS's,because
         everywhere-availability sets them somewhat ahead of IBM. Think about it.
         They are the richest software company in the world, why you ask....?

- -----BEGIN PGP PUBLIC KEY BLOCK-----
Version: 2.2

mQCNAi55t9cAAAEEALPB2u263I3AiYfu8nrg4rKEzC9eilcXvTzkIA+a2w6PDgZs
JstPYbWL7qXRGRnOhUGwYTenbfocRDopxoPDP63W3+FV495ZV77eSodDETNjStun
0y673DD6iqxJDZmHVktcfGPa+VoVkJJsJyNfXR0he6j+7wFPZ83MR/tcZHbHAAUR
tCRLYWkgSC4gU2NobGljaHRpbmcgPGthaUBwaGFudG9tLmNvbT4=
=km8k
- -----END PGP PUBLIC KEY BLOCK-----

-----BEGIN PGP SIGNATURE-----
Version: 2.2

iQCVAgUBLunHfs3MR/tcZHbHAQF/DAQAgUuHIYWfpZeDbY2G6pwYkY/jR4Lzl3Ln
X+SiJXxH+lA/p7vAZTB9kiNQ4Wss+dzCcxOCKnfQri748kuvSjknhjlSBNoNIEVK
PsxM6c/pUnsJzUHjcQUlF/ggjZluwvPDPmbcbpTdXhZz5EUJNTWCDPbjskQYHDPx
fMGvWteKgAg=
=MmMc
-----END PGP SIGNATURE-----