src/Metainfo.hs

   1 module Metainfo where
   2
   3 import Prelude hiding (lookup)
   4 import Bencode (BVal(..))
   5 import Data.ByteString.Char8 (ByteString, pack, unpack)
   6 import Data.Map as M ((!), lookup)
   7
   8 -- only single file mode supported for the time being.
   9 data Info = Info { pieceLength :: !Integer
  10                  , pieces :: !ByteString
  11                  , private :: !(Maybe Integer)
  12                  , name :: !String
  13                  , lengthInBytes :: !Integer
  14                  , md5sum :: !(Maybe String)
  15                  } deriving (Eq, Show)
  16
  17 data Metainfo = Metainfo { info :: !Info
  18                          , announce :: !String
  19                          , announceList :: !(Maybe [[String]])
  20                          , creationDate :: !(Maybe String)
  21                          , comment :: !(Maybe String)
  22                          , createdBy :: !(Maybe String)
  23                          , encoding :: !(Maybe String)
  24                          } deriving (Eq, Show)
  25
  26 mkInfo :: BVal -> Maybe Info
  27 mkInfo (Bdict m) = let (Bint pieceLength') = m ! Bstr (pack "piece length")
  28                        (Bstr pieces') = m ! Bstr (pack "pieces")
  29                        private' = Nothing
  30                        (Bstr name') = m ! Bstr (pack "name")
  31                        (Bint length') = m ! Bstr (pack "length")
  32                        md5sum' = Nothing
  33                    in Just Info { pieceLength = pieceLength'
  34                                 , pieces = pieces'
  35                                 , private = private'
  36                                 , name = unpack name'
  37                                 , lengthInBytes = length'
  38                                 , md5sum = md5sum'}
  39 mkInfo _ = Nothing
  40
  41 maybeBstrToString :: Maybe BVal -> Maybe String
  42 maybeBstrToString Nothing = Nothing
  43 maybeBstrToString (Just s) = let (Bstr bs) = s
  44                              in Just (unpack bs)
  45
  46 mkMetaInfo :: BVal -> Maybe Metainfo
  47 mkMetaInfo (Bdict m) = let (Just info') = mkInfo (m ! Bstr (pack "info"))
  48                            (Bstr announce') = m ! Bstr (pack "announce")
  49                            -- announceList = lookup (Bstr (pack "announce list"))
  50                            announceList' = Nothing
  51                            -- creationDate = lookup (Bstr (pack "creation date")) m
  52                            creationDate' = Nothing
  53                            comment' = lookup (Bstr (pack "comment")) m
  54                            createdBy' = lookup (Bstr (pack "created by")) m
  55                            encoding' = lookup (Bstr (pack "encoding")) m
  56                        in Just Metainfo { info = info'
  57                                         , announce = unpack announce'
  58                                         , announceList = announceList'
  59                                         , creationDate = creationDate'
  60                                         , comment = maybeBstrToString comment'
  61                                         , createdBy = maybeBstrToString createdBy'
  62                                         , encoding = maybeBstrToString encoding'
  63                                         }
  64 mkMetaInfo _ = Nothing