Break into pieces

Accomplished some advances for the torrent client… oh people we come closer to a release.

First I implemented the checking of Hash, when a piece is finished. To make sure there was no error in the network or so.

As next point on my list was the state machine for the Bittorrent network, which needs some simplification… so i made a little drawing of the states and transitions, its not very complicated, rather linear and implemented this behaviour. Works fine.

The next point is a big point on my list, a little bit complicated, multiple files. The pieces in the torrent stream are not stopping at a file border or so… just like a stream. On the first sight its not a big deal, if you have the pieces in an order.. but if they arrive randomly you have to calculate the position in the file and in the piece you recieved. For the sha1 calculation I have to keep the piece together, or I would just adjust the blocks inside a piece to get the file border. But I think I got it… downloaded just now a torrent file with 5 files in 3 different folders.. and it worked fine. Still needs a little bit finetuning for the recognition at start, if the file is already there and the sha1 check. Also I have to think about how to check if a file is finished (but not the whole torrent download) that I can rename it already and set free for the user.
I have one more point on my list before i would make a first alpha release…. tracker communication, multiple trackers, tracker reannounce, refresh peerlist, maybe also write an own communication with the tracker (non blocking you remember ;), the TfpHTTPClient is blocking of course)