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Padding Files

Padding files are used within a multi-file torrent to align the normal files to begin on piece boundaries.  This is generally not needed, and can add overhead in torrents that have many small files.

A padding file will have a name that starts with _____padding_file_.  Or it could have any name and be placed in the _pad directory at the root of the torrent.  Or it could have any name, and have a p in the attributes string when it is read from the torrent info.

A padding file must be all zeros.  This way, there is no need to save or track an actual file.  It will always be read as zeros and this will allow piece hashes to be correctly calculated at the tail end of normal files.