libtorrent is a C++ library that aims to be a good alternative to all the other bittorrent implementations around. libtorrent is a library and not a full featured client, although it comes with a working example client.
The main goals of libtorrent are:
· to be cpu efficient
· to be memory efficient
· o be very easy to use
libtorrent is portable at least among Windows, MacOS X and other UNIX-systems. It uses Boost.Thread, Boost.Filesystem, Boost.Date_time and various other boost libraries as well as zlib (shipped) and asio (shipped). At least version 1.33.1 of boost is required.
Since libtorrent uses asio, it will take full advantage of high performance network APIs on the most popular platforms. I/O completion ports on windows, epoll on linux and kqueue on MacOS X and BSD.
libtorrent has been successfully compiled and tested on:
· Windows 2000 vc7.1, vc8
· Linux x86 GCC 3.3, GCC 3.4.2
· MacOS X (darwin), (Apple's) GCC 3.3, (Apple's) GCC 4.0
· SunOS 5.8 GCC 3.1
· Cygwin GCC 3.3.3
· GCC 2.95.4
Here are some key features of "libtorrent":
· Trackerless torrents (using a kademlia DHT)
· multitracker extension support (as specified by John Hoffman)
· serves multiple torrents on a single port and in a single thread
· gzipped tracker-responses
· HTTP seeding, as specified by Michael Burford of GetRight.
· piece picking on block-level (as opposed to piece-level). This means it can download parts of the same piece from different peers. It will also prefer to download whole pieces from single peers if the download speed is high enough from that particular peer.
· queues torrents for file check, instead of checking all of them in parallel.
· supports http proxies and proxy authentication
· uses separate threads for checking files and for main downloader, with a fool-proof thread-safe library interface. (i.e. There's no way for the user to cause a deadlock). (see threads)
· can limit the upload and download bandwidth usage and the maximum number of unchoked peers
· piece-wise, unordered, incremental file allocation
· implements fair trade. User settable trade-ratio, must at least be 1:1, but one can choose to trade 1 for 2 or any other ratio that isn't unfair to the other party.
· fast resume support, a way to get rid of the costly piece check at the start of a resumed torrent. Saves the storage state, piece_picker state as well as all local peers in a separate fast-resume file.
· supports an extension protocol. See extensions.
· supports files > 2 gigabytes.
· supports the no_peer_id=1 extension that will ease the load off trackers.
· supports the udp-tracker protocol by Olaf van der Spek.
· possibility to limit the number of connections.
· delays have messages if there's no other outgoing traffic to the peer, and doesn't send have messages to peers that already has the piece. This saves bandwidth.
· does not have any requirements on the piece order in a torrent that it resumes. This means it can resume a torrent downloaded by any client.
· adjusts the length of the request queue depending on download rate.
· supports the compact=1 tracker parameter.
· selective downloading. The ability to select which parts of a torrent you want to download.
· ip filter
What's New in This Release: [ read full changelog ]
· fixed https crash
· added some functions missing from the python binding
· fixed rare piece picker bug
· fixed invalid torrent_status::finished_time
· fixed bugs in dont-have and upload-only extension messages
· don't open files in random-access mode (speeds up hashing)