The old implementation calculates download/upload statistics for a
RequestGroup by summing up all PeerStat objects. For global
statistics, those are summed together. This clearly incurs runtime
penalty and we introduced some kind of caching which updates
statistics every 250ms but it did not work right.
This change removes all these aggregation code, and instead makes
RequestGroup and RequestGroupMan objects hold NetStat object and
download/upload bytes are directly calculated by thier own NetStat.
This is far more simplar than the old way and less runtime penalty and
brings more accuracy.
Using off_t, at least, in DiskAdaptor layer is problematic because
torrent can contain under 2GiB files but total sum of those files may
exceed 2GiB limit, which makes off_t overflow in 32 bit system without
large file support. So we use int64_t in API. We'll check the file
length before download so that it does not exceed max off_t.
Added .cc file for classes/structs that only provided by header
file. Defined non-POD classes' ctor, dtor in .cc file. Moved
implementation code in header file to .cc file for major
classes/strucsts.
Tatsuhiro Tsujikawa