[BusyBox] Unarchive applets; new code overview

[Glenn McGrath]

Adam Heath wrote:
> 
> On Mon, 11 Jun 2001, Glenn McGrath,,, wrote:
> 
> > I discovered that problem when i modified gunzip, to do a second pass i
> > close the pipes and reopen them from the start, then loop calling
> > getchar() to seek forwards
> 
> I hope we don't have tons of loop calling getchar() code all over the place.
> If we need to do skips, we should have some generic code.  In fact, if you
> look at cat,  you might find something similiar.
> 
> In dpkg code, I actually implemented something like this.  When I need to
> seek, I call lseek().  If that fails with an invalid argument(ie, ISPIPE), I
> then fall back on a buffer_copy, to /dev/null.
> 

There is one loop in extract_archive, the purpose of this function is to
be generic and usable by any of the unarchiving applet. I do see your
point about lseeking when possible to increase performance, i will look
into it.


Glenn