How to get size of packed file in 7-zip archive

Question

I'm using SevenZipSharp and it has Size property in ArchiveFileInfo struct, that "Gets or sets size of the file (unpacked)".

How can I get size of packed file in archive?

Answer 1

Unfortunately it seems that SevenZipSharp doesn't fill this info. Here's for example how it fills unpacked size in ArchiveFileInfo:

var fileInfo = new ArchiveFileInfo { Index = (int)i };
...
_archive.GetProperty(i, ItemPropId.Size, ref data);
fileInfo.Size = NativeMethods.SafeCast<ulong>(data, 0);

ItemPropId enum has PackedSize property which is not used though, I suppose due to the fact it may be absent (according to the comment):

/// <summary>
/// Item packed sise; usually absent
/// </summary>
PackedSize,

So I guess the only way to get it is to fork SevenZipSharp and try to fix it yourself (or search for an already existing fork). If it's possible at all.