src/tnef/file.hs

   1 --
   2 -- Copyright Michael Orlitzky
   3 --
   4 -- http://michael.orlitzky.com/
   5 --
   6 -- This program is free software: you can redistribute it and/or modify
   7 -- it under the terms of the GNU General Public License as published by
   8 -- the Free Software Foundation, either version 3 of the License, or
   9 -- (at your option) any later version.
  10 --
  11 -- This program is distributed in the hope that it will be useful,
  12 -- but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 -- GNU General Public License for more details.
  15 --
  16 -- http://www.fsf.org/licensing/licenses/gpl.html
  17 --
  18
  19 module Tnef.File where
  20
  21 import Data.Binary
  22 import qualified Data.Binary.Get as BinaryGet
  23 import qualified Data.Binary.Put as BinaryPut
  24 import Data.Int (Int64)
  25 import Tnef.Attachment
  26 import Tnef.Object
  27
  28
  29 -- A TNEF "file" has a signature at the top which should be the same
  30 -- for all TNEF files. There's also a "key," which probably does
  31 -- something, and looks to be unique. After that, there's a variable
  32 -- number of objects (whose structure can be seen in TnefObject). The
  33 -- "total bytes" thing is not part of the file. I'm just using it to
  34 -- keep track of the bytes read for now (to make sure it equals the
  35 -- size of the file when we're done).
  36 data TnefFile = TnefFile { signature    :: Word32,
  37                            key          :: Word16,
  38                            first_object :: TnefObject,
  39                            total_bytes  :: Int64 }
  40
  41
  42 -- Magicest of numbers
  43 -- Important: Int doesn't guarantee 32 bits, so we
  44 -- need to use the Integer type here.
  45 tnef_signature :: Integer
  46 tnef_signature = 0x223e9f78
  47
  48
  49
  50 instance Show TnefFile where
  51     show x = "Signature: " ++ (show (signature x)) ++ " (Correct: " ++ (show tnef_signature) ++ ")\n" ++
  52              "Key: " ++ (show (key x)) ++ "\n" ++
  53              concat (map show (get_object_list x)) -- Show the objects, one at a time
  54
  55
  56 -- Recursively collect an array of objects. It dies
  57 -- on the last one, which has no next_object property.
  58 -- Help?
  59 get_object_list :: TnefFile -> [TnefObject]
  60 get_object_list x = get_successive_objects (first_object x)
  61
  62
  63 get_successive_objects :: TnefObject -> [TnefObject]
  64 get_successive_objects Nil = [Nil]
  65 get_successive_objects x = (x : (get_successive_objects (next_object x)))
  66
  67
  68 instance Binary TnefFile where
  69     put _ = do BinaryPut.putWord8 0
  70     get = do
  71       signature_word    <- BinaryGet.getWord32host
  72       key_word          <- BinaryGet.getWord16host
  73       first_object_word <- get :: Get TnefObject
  74       total_bytes_word  <- BinaryGet.bytesRead
  75       return (TnefFile { signature      = signature_word,
  76                          key            = key_word,
  77                          first_object   = first_object_word,
  78                          total_bytes    = total_bytes_word })
  79
  80
  81 write_tnef_file :: TnefFile -> [IO ()]
  82 write_tnef_file x = do
  83   let objects = get_object_list x
  84   let attachments = get_attachment_list objects
  85   map write_attachment attachments