Writing empty files into ZipOutputStream triggers CRC32 error

Steps to reproduce

1. Create a 0-byte file on the disk.
2. Try to zip it using code like this:

FileStream ostream = File.OpenRead(file);
obuffer = new byte[ostream.Length];
ostream.Read(obuffer, 0, obuffer.Length);
zipOutputStream.Write(obuffer, 0, obuffer.Length);

Expected behavior

The file should be added successfully to the zip stream.

Actual behavior

A CRC32 error is thrown ("not a valid index into buffer").

Workaround

Prevent writing into the archive stream the empty file, e.g.

if (obuffer.Length > 0)
    zipOutputStream.Write(obuffer, 0, obuffer.Length);

Version of SharpZipLib

Obtained from (place an x between the brackets for all that apply)

• Compiled from source
  • branch: master
  • commit: 00c3c91
• Downloaded DLL from GitHub
• Downloaded DLL from SourceForge
• Downloaded DLL from _______
• DLL included as part of
• Package installed using:
  • NuGet
  • MyGet
  • Chocolatey

[Numpsy]

Think this one is already fixed, but extra unit test for the issue @ #469 in case it's useful.

[piksel]

Now we can close this with good conscience!