readme.txt

一个delphi中压缩的组件VCLZip

VCLZip Native Delphi Zip/UnZip Component! (Version 2.23 April 14th, 2002)

IMPORTANT:  Please be sure to always re-install/rebuild the components (VCLZip and VCLUnZip) to the component pallette (or rebuild the design time package) so that the ThisVersion property and any other new properties will be properly updated.

***IMPORTANT: Please remember do not install these components into a package by the name of either VCLZip or VCLUnZip.  You will receive an error if you do.

PLEASE TAKE A LOOK AT THE "WHAT's NEW IN THIS VERSION" LINK IN THE HELP FILE AS IT HAS CONVENIENT LINKS TO ALL OF THE NEW TOPICS.

============
Version 2.23

Added the OEMConvert property.  Filenames stored in a PKZip compatible archive normally go through an OEM conversion to make them ascii compatible.  When opening the zip file the conversion is undone.  If you do not plan on having other zip utilities opening up your archives this conversion process is not really necessary.  Setting this property to False will eliminate this process.  The default value for this property is True for normal PKZip compatability.

Added OnEncrypt and OnDecrypt events.  These allow you to replace the standard pkzip encryption with your own.  Data is passed to these events a buffer at a time.  Use this with care as this is still somewhat experimental and I'm not sure how useful it is yet.  You must make all changes within the buffer sent in to you.  Treat the entire file as a stream.  Byte for byte replacement only.  No additional keys can be saved.

Added OnRecursingFile event.  Sometimes when using wildcards and recursing directories, there was no reporting of progress.  This will be fired each time a file matches as the file list is being built while recursing directories.

Added the EncryptBeforeCompress boolean property.  The default for this property is False and if left like this VCLZip will behave like normal.  If set to True, VCLZip will encrypt each buffer prior to compressing it instead of afterwards.  This will cause files to not be decryptable by normal zip utilities thereby adding a bit of extra security.

Bugs Fixed:

IMPORTANT!!!  Behavior of freeing the ArchiveStream (compressed stream) has been modified.  VCLZip will now no longer try to free ArchiveStream, you must free it yourself.  This was due to a problem where it would be freed automatically if there was a problem with the ArchiveStream when trying to open it as a zip file (possibly corrupt).  Best practice is that ArchiveStream should always point toward a TMemoryStream that you create anyway.

Modified the SFX code (the code used to create the SFX stub distributed with VCLZip) so that it handles filenames that have been run through an OEM Conversion.  The SFX was losing accented characters.  This modification means that if you are creating zip files to be used as SFX's you will want to leave the OEMConvert property mentioned above, set to it's default value of True.

Modified so that when cursor is changed to hourglass by VCLZip, previous cursor is saved correctly instead of just changing it back to default cursor.

Now saves Central Directory Extra Fields correctly.

Fixed the SFX code so that it works properly if you use Copy /B to concatenate a zip file to the stub.

Due to a Delphi strange behavior sometimes path names for directory only entries would become corrupted.

Removed reference to QConsts, replaced with RTLConsts.

Sometimes a GPF would result if a corrupt zip file was opened.

Using a wildcard in pathname added to FilesList did not work.

Using '*.*' as a wildcard in files added to FilesList now is the same as using '*'.

VCLZip will now check for CancelTheOperation during initial building of the fileslist instead of just during compression processing.

Added a final call to OnTotalPercentDone with 100% because this didn't always happen.

Attributes were not getting set correctly for directory-only entries.

Fixed a problem that was not allowing ZipComment's to be added correctly to spanned or blocked zip files.  Not the same fix as in 2.22.

Directories (directory-only entries) were not being restored properly unless DoAll was True.

You were unable to delete a directory from which files were recursively zipped until exiting your application.


============
Version 2.22

Now Delphi 6 compatible.

New event called {link=93,OnRecursingFile} which gets called as VCLZip recurses directories searching for files that match a wildcard that is entered in the FilesList.  This gets called each time a file matches the wildcard.

Fixed a bug which kept diskettes from being labeled when creating spanned zip files on WIN31.

Fixed a bug which sometimes did not allow zip comments to be added to blocked zip sets.

Fixed a bug which caused VCLZip to not properly handle the IncompleteZip exception on spanned zip sets unless you called ReadZip prior to calling UnZip.


Version 2.21 (Changes are shown in the build stages as they were implemented)

Pre-Release Build 5:

When working with temporary files, VCLZip will now rename, instead of copy, the temp file if the destination is on the same drive.  This will speed up the adding of files to an existing zip file when the resulting zip file is very large.

Pre-Release Build 4:

New event called OnPrepareNextDisk which is an event that will allow you, when creating spanned zip files across diskettes, to do things like format a diskette that has just been inserted, or to add or delete files from the diskette before continuing with the zipping process.

Fixed a problem that was causing the CancelTheOperation Method to not work properly.


Pre-Release Build 3:

Fixed bug which caused VCLZip to miscalculate space needed for zfc file if wildcards are put into the FilesList.

Fixed bug so you could have FilePercentDone without needing TotalPercentDone when creating spanned zip files

Fixed so relative_offset set correctly for spanned zips.  Side effect of removing needless write of header.

Added code to read local fileheaders if exception thrown when reading a central fileheader.

Fixed problem where directories couldn't be created from directory entries because the fullpath wasn't known yet.  Result of having moved this code to earlier.

Fixed typo in creation of LOC header values which could cause error if reading local headers.

Changed so Zip Comment starting position is calculated based on end of central record instead of end of file.


Pre-Release Build 2:

IMPORTANT: Changed default for FileOpenMode back to fmShareDenyNone as it had been for all but version 2.20.

Fixed a problem where drivepart (i.e. C:\) was not being stripped when saving relative paths.

Added a BufferedStreamSize property which can increase the speed of creating zips to floppy (and other slow media) dramatically.  The new default for this should increase the speed by as much as 3 times, but you can now tweak this especially for your application!

Added an ImproperZip property which gets set when VCLZip detects an inconsistency with the zip.  This can be useful for detecting when VCLZip was able to open the zip in spite of an inconsistency found.  There was no way to know this in the past.

Fixed a problem where zip comments in zfc files were not being read correctly.

Added a setZipSignatures procedure which allows you to modify the signatures of your zip file.  This will cause other zip utilities to not be able to recognize or read your zip files created with VCLZip.  Useful if you want to add further security to your zip files.

Pre-Release Build 1:

Some zip files would not open correctly, throwing an incomplete zip file exception due to an erroneous "extra field length" identifier in headers of some compressed files. These zip files are rare, but a very few people seemed to have several of them. This problem would not affect zip files created by VCLZip, and this problem should only occur in VCLZip 2.20, not in any previous version. 

If you had Range Checking turned on, VCLZip would get a range check error when using a wildcard that ended with a * as in 'somefile.*'. 

Under certain circumstances, drive information would not be stripped from path information if zipping recursively (including subdirectories) 

"Retrying" to zip a file that could not be opened using the OnSkippingFile event would not always work correctly. 

Creating spanned zip set to floppy should be faster now due to removing a needless header write to disk for each file. 

VCLZip would not compile correctly with MAKESMALL defined. 

Added code to make VCLZip work with BCB5. Haven't tested this yet though since I don't have BCB5 myself yet. 

Added readonly boolean ImproperZip property which will be set to True when some sort of problem is found when opening the zip file, even if recoverable. This property will be enhanced and refined in the future. 

If KeepZipOpen is set to True, when putting in the wrong disk in a spanned zip set, VCLZip would not always properly close the file on the old diskette before trying to open the file on the next diskette. 

Added ECantWriteUCF exception which will be thrown if VCLZip runs out of room to write the uncompressed file when unzipping. 

Timestamp was not being set properly when unzipping readonly files. Moved setting of the timestamp to before the attributes get set. 

============
Version 2.20

Changes have been made in the following areas:

--Performance

There are a few code optimizations that should speed up the zipping process slightly.

--Spanned Zip Files

A new feature, turned on with the SaveZipInfoOnFirstDisk allows VCLZip to create and read spanned zip files starting with the first disk instead of the normally required last disk of the spanned disk set by saving a Zip Configuration File on the first disk.  This feature can be used even if creating the spanned zip file directly to your hard drive.

A new property, SaveOnFirstDisk, allows you to save room on the first disk when creating a spanned zip file, to allow room for other files, such as setup programs, data files, or a Zip Configuration File.

Spanned zip files can now be directed toward disks greater than 2 gig in size as long as you are using Delphi 5 or BCB 4.

--UnZipping

The new Selected indexed property offers another way to flag files to be unzipped.  Files that have the Selected property set to True can be unzipped using the UnZipSelected method.  The Selected property will be cleared (set to False) for each file as it is unzipped, but you can also call the ClearSelected method to clear them all.  At anytime the NumSelected property can be checked to see how many files have been selected.

Also, the UnZipToBufferByIndex and UnZipToStreamByIndex methods allow you to unzip files specified by their index instead of by name or wildcard.

The BufferLength property allows buffered output (buffer smaller than the total uncompressed filesize) when unzipping directly to memory (see UnZipToBuffer and UnZipToBufferByIndex).  This will cause the OnGetNextBuffer Event to be called everytime BufferLength bytes have been output by VCLZip.

Modified to work in all ways with zip files that have "extra fields" in their headers. These tend to be quite rare, but they do show up from time to time.

--Zipping

Added a property called FileOpenMode which allows you to define the file open mode for files when they are opened to be zipped.