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If I create a #Zip file from .Net I get errors when reading it from Java using the Java.Utils.Zip library.

Examining the file created via AEX tool it seems there is an error of mismatch between compressed and uncompressed size in the local file entry, while the central file header is correct:

<<Local file entry
 Version 4.5
 Flags   0000   Normal compression
 Method  Deflated
 Date    9/2/2008 10:33:36 AM
 Name    'Connectors.config'
 Crc     68741CD4   Compressed size 128  Uncompressed size 140 
 Header mismatch - compressed size different
 Header mismatch - uncompressed sizes are different

<<Central file header
 Version                 made by 4.5   to extract 4.5
 OS                      MSDOS + OS/2,NT (FAT+VFAT+NTFS)
 Flags                   0000   Normal compression
 Method                  Deflated
 Name length             17
 Comment length          0
 Internal attributes     00
 External attributes     0000 MSDOS ------
 Name                    'Connectors.config'
 Disk number start       0
 Relative header offset  0
 Crc    68741CD4   Compressed size 128  Uncompressed size 140 

<<End of Central file header
 Disk number             0
 Start dir disk number   0
 Entries this disk       1
 Total entries           1
 Central directory size  83
 Offset                  195

EOF
Done

I've tried various options assigning compressed and uncompressed size to the zipentry but it fails every time, only way I've found to make it work is to store the file (so no compression happens) and assigning Size and CompressedSize to be the same as file length, but this makes compressing files useless:

FileInfo fileInfo = new FileInfo(FileFullPathName);using (FileStream fs = File.OpenRead(FileFullPathName))

{

byte[ buffer = new byte[fs.Length];

fs.Read(buffer, 0, buffer.Length);

 

ZipEntry entry = new ZipEntry(fileInfo.Name);entry.CompressionMethod = CompressionMethod.Stored;

entry.CompressedSize = fs.Length;

entry.Size = fs.Length;

entry.DateTime = DateTime.Now;

fs.Close();

 

Zipper.PutNextEntry(entry);

Zipper.Write(buffer, 0, buffer.Length);

Zipper.Flush();

Zipper.CloseEntry();

}

 This is instead the code I'm using that fails, if I set any kind of property to Size or CompressedSize the AEX tool fails also on the Central File Header part :

FileInfo fileInfo = new FileInfo(FileFullPathName);using (FileStream fs = File.OpenRead(FileFullPathName))

{

byte[ buffer = new byte[fs.Length];

fs.Read(buffer, 0, buffer.Length);

ZipEntry entry = new ZipEntry(fileInfo.Name);

entry.DateTime = DateTime.Now;

fs.Close();

Crc32 crc = new Crc32();

crc.Reset();

crc.Update(buffer);

entry.Crc = crc.Value;

Zipper.PutNextEntry(entry);

Zipper.Write(buffer, 0, buffer.Length);

Zipper.Flush();

Zipper.CloseEntry();

}

 

Suggestions???

Regards

Massimo

 

 

Hi,

Try not setting the sizes at all.  Its ok to set the uncompressed size and this works fine for me and helps with Zip64 issues. (What version of the library are you using?)

Cheers, -jr-

I'm using the latest version (0.85.5.452).

Current code do not set any size, because if I set any of them also the TestArchive function of #ZipLib fails when I test the created archive in the code following.

I've made some test trying to force the usage of Zip64, but the result remained the same, AEX gives an error and the file cannot be decompressed from the Java library.

 Regards

Massimo

 

 Hi,

You arent tracking the number of bytes read from the file but rather are adding the entire buffer which may the problem.

hth, -jr-

Could you post a quick code sample about how to track this info?

 Regards

Massimo

I've tried to place an Assert on the fs.Length and the number of bytes read from the buffer but, for all cases I have, the values are the same.

 My idea it's a problem in the library code, specifically in the Zip header write (that has also a TODO Refactor comment in it) that always assign -1 to the compressed size of the entry.

Regards

Massimo