DotNetZip Creates corrupt archives (bad CRC)
c#, checksum, dotnetzip, zip
Solution
`GetBuffer` is certainly wrong. It returns the internal buffer of the `MemoryStream`, which is often bigger than the actual content.
To return an array that only contains the actual content, use `ToArray()`.
Or you could carefully handle the incompletely filled buffer in the consuming code. This would reduce GC pressure, since you don't need to allocate a whole new array for the return value.
If the zip-archive is large, I'd also consider saving to a file directly, instead of assembling the archive in-memory.
Problem
There's a strange problem with DotNetZip that I can't seem to find a solution to. I've searched for a few hours now and I just can't find anything on this, so here goes. ``` var ms = new MemoryStream(); using (var archive = new Ionic.Zip.ZipFile()) { foreach (var file in files) { // string byte[] var entry = archive.AddEntry(file.Name, file.Data); entry.ModifiedTime = DateTime.Now.AddYears(10); // Just for testing } archive.Save(ms); } return ms.GetBuffer(); ``` I need to add the modified time, which is rather crucial, but right now I just have a dummy timestamp. When I open the file with WinRAR, it says "Unexpected end of archive". Each individual file has checksum 00000000, and WinRAR says "The archive is either in unknown format or damaged". I can repair it, which brings it down 20% in size and makes everything OK. But that's not really useful.. When I make a breakpoint after adding all the entries, I can see in `zip.Entries` that all the entries have that same bad CRC, but all the data seems to be there. So it shouldn't be the way I save the archive that's the problem. I use my file collection elsewhere without problems, which adds to DotNetZip being weird. Well either that or I misunderstand something :)