When I pack a zip using WinRar for example and select the "store" method for an uncompressed archive, the algorithm used is reported as "store" and the file size is only a few hundred bytes larger than the compressed data.

But using rubyzip, even when I select Zlib::NO_COMPRESSION something weird happens:

• the file indeed has no compression (I can see parts of the original data readable inside), but the resulting zip size is larger, it gains about 8 KB on a 60 MB file
• the file being zipped is not stored as a raw blog inside the zip but it's chunked with some kind of checksums mixed in
• the algorithm reported is "deflate" instead of "store"

This is a problem for situation where a truly uncompressed zip is needed, with a raw binary version of the original file inside.

Am I doing something wrong? Is there a way to force the gem to work this way, or is this a bug?