54 lines
2.0 KiB
Haskell
54 lines
2.0 KiB
Haskell
{-# LANGUAGE NamedFieldPuns #-}
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import Codec.Compression.Zlib (decompress)
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import Data.ByteString.Lazy.Char8 (ByteString)
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import qualified Data.ByteString.Char8 as BS (readFile)
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import qualified Data.ByteString.Lazy.Char8 as Lazy (fromStrict, putStr, toStrict)
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import Data.Map ((!?))
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import qualified Data.Map as Map (keys, lookup)
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import PDF (Document(..), parseDocument)
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import qualified PDF.EOL as EOL (Style)
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import PDF.Object (Content(..), DirectObject(..), Object(..), Name(..))
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import PDF.Output (ObjectId(..))
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import qualified PDF.Output as Output (render)
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import PDF.Update (unify)
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import System.Environment (getArgs, getProgName)
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import System.Exit (die)
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import Text.Printf (printf)
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display :: EOL.Style -> Object -> ByteString
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display eolStyle d@(Direct _) = Output.render eolStyle d
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display eolStyle s@(Stream {header, streamContent}) = Output.render eolStyle $
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case Map.lookup (Name "Filter") header of
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Just (NameObject (Name "FlateDecode")) -> Stream {
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header
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, streamContent = Lazy.toStrict . decompress $ Lazy.fromStrict streamContent
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}
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_ -> s
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extractObject :: ObjectId -> Document -> Either String ByteString
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extractObject objectId (Document {eolStyle, updates}) =
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case objects content !? objectId of
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Nothing -> Left $ "No object has ID " ++ show (getObjectId objectId)
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Just o -> Right $ display eolStyle o
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where
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content = unify updates
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listObjectIds :: Document -> Either String [String]
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listObjectIds =
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Right . prependTitle . toString . Map.keys . objects . unify . updates
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where
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toString = fmap (show . getObjectId)
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prependTitle = ("ObjectIds defined in this PDF:":)
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main :: IO ()
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main = do
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(inputFile, getData) <- parse =<< getArgs
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input <- BS.readFile inputFile
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either die id $ (parseDocument input >>= getData)
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where
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parse [inputFile] = return (inputFile, fmap (mapM_ putStrLn) . listObjectIds)
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parse [inputFile, objectId] = return
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(inputFile, fmap Lazy.putStr . extractObject (ObjectId (read objectId)))
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parse _ = die . printf "Syntax: %s inputFile [OBJECT_ID]\n" =<< getProgName
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