Add hints to random access availability to archives

Following #707

I’ve noticed you really don’t know if you need to read sequentially or you can access randomly until you have opened the archive… correct me if I’m wrong:

Plain .TAR files can actually be read randomly… but tar archives inside a gzip archive can’t

So, if that’s the case, the SupportsRandomAccess property should go into the IArchive, not in the IArchiveFactory interface, right?

Also, wouldn’t the IsSolid property would be enough for this? (in that case, IsSolid should be true for .tar.gz files, I’ve checked and currently it’s false)

If IsSolid serves a different purpose, then, IArchive definitely needs a SupportsRandomAccess

Any thoughts?

[adamhathcock]

So, SevenZip doesn’t have an implementation in the readers factory? is there a reason for it?

This is because 7Zip requires random access to a file from my memory. The streams need to seek around to properly find headers and decompress the streams in the format. Readers only work for non-seekable streams.

[adamhathcock]

You’ll have to implement that yourself if you can’t guarantee Reader. It’s beyond the scope of the library.

I’ve been away for personal reasons.