readme.txt

完整的解压zip文件的源码。包含密码功能

Macintosh Port of Info-Zip's Zip
by Dirk Haase, [e-mail]
homepage:   www.sitec.net/maczip
13.November 1998
================================


Some notes about this port:
===========================

MacZip requires at least System 7 and a Macintosh with a minimum of a
Motorola 68020 or PowerPC 601 processor. Other configurations may work
but it is not tested at all.

The application is distributed as a fat binary with both regular 68K
and native PowerPC versions included.

Move the executable(s) somewhere--for example, drag it (or them) to your
Applications folder.  For easy access, make an alias in the Launcher Control
Panel or directly on your desktop.
The GUI is very simple. It was not my intention to make a full-blown GUI,
however I think it is comfortable enough to use it as regular tool.

This port supports also Apple-event.So you can install it in your
WWW-Browser as a helper-app.

For more Info about the contents of this package, take a look into
the "macos/Contents" (or :macos:Contents) file. Some notes on how to
rebuild the Macintosh applications can be found in INSTALL.



Usage:
------

To extract a Zip archive, just drop it on MacZip.
MacZip will start and extract all files in a separate folder.
Or
Start MacZip; choose the app you want in the menu "Current App".
Select "File->Command Line" execute your selected app with the
Unix-style command-line
Or select
"File->Start Zip/Unzip" to execute your app via dialog-box.
For more information about switches choose File->Get help on
Zip/Unzip. A short introduction is also available online:
http://www.sitec.net/maczip/How-To-Do/

It's possible to stop the run of Zip/Unzip with the well
known shortcut [Command] + [.].

There are some Mac-specific switches available.
Zip Module:
       -df    [MacOS   only]  Include  only  data-fork  of  files
              zipped into the archive.  Good for exporting  files
              to  foreign operating-systems.  Resource-forks will
              be ignored at all.

       -jj    [MacOS  only] record Fullpath (+ Volname). The com-
              plete  path  including  volume  will  be stored. By
              default the relative path will be stored.

       -S     Include system and hidden  files.  This  option  is
              effective  on  some  systems only; it is ignored on
              Unix.  On MacOS, this option includes finder invis-
              ible files, which are ignored otherwise.

Unzip Module:
       -E     [MacOS only] display contents of MacOS extra  field
              during restore operation.

       -i     [MacOS only] ignore filenames stored in MacOS extra
              fields.  Instead,  the  most  compatible   filename
              stored in the generic part of the entry's header is
              used.

       -J     [MacOS only] ignore MacOS extra fields.  All Macin-
              tosh  specific  info  is  skipped.  Data-fork   and
              resource-fork are restored as separate files.




Performance and Limitations:
----------------------------

I was curious about performance items. So I took one small test on my 200 PPC
under MacOS 8.1. To compare `Drop Stuff' with `MacZip' I archived my Netscape
folder:
143 Files in 21 folders about 15.6 Megabytes.

Compress:
Drop Stuff (4.0) needs 70 sec to compress and additional 20 sec to create
a HQX file.
Compression ratio: 2.01 times smaller
MacZip needs 45 sec to compress, so it's about 1.5 - 2 times faster.
Compression ratio: 2.06 times smaller

Expand:
Stuffit Expander (4.02) needs 35 sec to create a '.sit' file and
additional 35 sec to expand all files.
MacZip need 25 sec to expand all files so it's 1.7 - 3.5 times faster.


Limitations/Problems:

    - Aliases are not supported. I tried, but I got broken aliases
      This port will silently ignore all aliases.
      It's on my to-do list for future releases.

    - Zip needs much memory to compress many files:
      You may need to increase the 'Preferred Size' in 'Get Info'.
      Values of 12 Megabytes or more are possible

    - Unzip needs about 500 Kbyte of memory to unzip no matter
      how many files were compressed and expanded.

    - and finally one big macintosh-related problem:
      This port has one weak point: It's based on pathnames.
      As you may be already know: Pathnames are not unique on a Mac !
      The main reason is that an attempt to implement support exact saving of
      the MacOS specific internal file-structures would require a throughout
      rewrite of major parts of shared code, probably sacrifying compatibility
      with other systems.
      I have no solution at the moment. The port will just warn you if you try
      zip from / to a volume which has a duplicate name.
      MacZip has problems to find the archive or the files.
      My (Big) recommendation: Name all your volumes with a unique name and
      MacZip will run without any problem.


Known Bugs:

    - Display of comments stored in the zip-file is in a mess.

    - crypted files in a zip archive are sometimes corrupt:
      I get an error message: invalid compressed data to inflate.
      Appearance of this error is purly be change:
      I did a small test: Unzipping an archive containing 3589 files
      56 files fails to unzip, so about 1.5%

I strongly recommend to test your archive (eg. unzip -t archive).




Zip-Programs / Macintosh Extra-Data:
-----------------------------------------
A brief overview:
Currently, as far as I know, there are 4 Zip-Programs available
for the Macintosh platform.
These programs build (of cause) different variants of Zip-Files:

    - Info-Zip's first Port of Zip. Ported by Johnny Lee
      This Port is rather outdated and no longer supported (since 1992).
      68K only. Only minimal Mac-info is stored (Creator/Type,
      Finderattributes).
      Until now, Only Unzip 5.32 survived.

    - ZipIt by Tom Brown. This is Shareware and still supported I think.
      ZipIt has a nice GUI, but I found it can't handle large Zipfiles
      quite well. ZipIt compresses Macintosh files using the MacBinary
      format. So, transfering files to other platforms is not so easy.
      Only minimal Mac-info is stored (Creator/Type, Finderattributes).
      Macfilenames are changed to a most compatible filename.

    - PKZIP/mac v2.03/210d. This is Shareware.
      This Zip implementation for the Mac can be found on ASI's website
      (http://www.asizip.com/products/products.htm).  The name of this
      program is misleading, it is NOT a product from PKWARE.  ASI last
      release version is v2.03, and they also offer a newer beta version
      PKZIP/mac 210d. But even the Beta version is rather outdated (1995).
      Only minimal Mac-info is stored (Creator/Type, Finderattributes).
      The Zipfile format looks like incompatible to other platforms.
      (More details about the compatibility issue can be found in
      proginfo/3rdparty.bug!)
      Macfilenames are restored without any change.

and finally:
    - Info-Zip's latest Port of Zip. MacZip 1.0. Ported by me :-)
      It is supported (of cause) and up to date. Fullset of macintosh
      info is stored: Creator/Type, Finderattributes, Findercomments,
      MacOS 8.0 Foldersettings, Icon/Folder-Positions ...
      Macfilenames are restored without any change.

Compatibility of my port; Extraction:
   - Archives from Info-Zip's first port (by Johnny Lee) are still compatible.
   - Archives from ZipIt can be extracted, but some files will still
     remain in a MacBinaryformat, no Finderinfo will be restored.
   - PKZiP/mac archives-files are extracted without resource-forks
     and without any Finderinfo. I have no information about that zip-format.

Compatibility of my port; Compression:
   - My port supports only the new Info-Zip format
     (introduced with this port). Therefore archives created by MacZip 1.0
     (1998) must be extracted with this version or later releases of Info-ZIP's
     UnZip to restore the complete set of Macintosh attributes.

Note: This port is complete unrelated to the shareware ZipIt. Even more,
handling of special Macintosh attributes is incompatible with ZipIt.
This port (MacZip) may be used to extract archives created by ZipIt,
but the Resource fork and the extra field of ZipIt will be ignored.
Make sure that you get the result as you expected.



Macintosh Files; File Forks:
----------------------------

All Macintosh files comprise two forks, known as the data fork and the
resource fork.  Unlike the bytes stored in the resource fork, the bytes in
the data fork do not have to exhibit any particular internal structure.