Fix error on Next() when skipping files.

[ajnavarro]

With this change, we discard remaining bytes for the actual file to
avoid errors on partial reads or skipping files calling Next()
without reading.

Several optimizations are possible, like directly Seek to the next file
without reading the previous one, if the underlying reader supports it.

Signed-off-by: Antonio Navarro Perez [email protected]

[saracen]

Thank you for this @ajnavarro!

I don't have much time at the moment, but I'll take a look at this, try it and refamiliarise myself with the codebase at the weekend.

Several optimizations are possible, like directly Seek to the next file
without reading the previous one, if the underlying reader supports it.

I think the reason we're not directly seeking here is because we actually need to read and decompress the previous content in the "folder". Reading and discarding causes the underlying reader to decompress for us.