60 lines
2.0 KiB
Haskell
60 lines
2.0 KiB
Haskell
{-# LANGUAGE NamedFieldPuns #-}
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{-# LANGUAGE OverloadedStrings #-}
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module Main where
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import Codec.Compression.Zlib (compress, decompress)
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import Data.ByteString.Char8 (ByteString)
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import qualified Data.ByteString.Char8 as BS (
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length, readFile
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)
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import qualified Data.ByteString.Lazy.Char8 as Lazy (
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fromStrict, intercalate, split, toStrict, writeFile
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)
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import qualified Data.Map as Map (insert, lookup)
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import PDF (Document(..), parseDocument, render)
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import PDF.Object (Content(..), DirectObject(..), Object(..), Name(..), Number(..))
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import PDF.TextRendering (TextRendering(..), update)
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import Prelude hiding (lines, unlines)
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import System.Environment (getArgs)
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import System.IO (hPutStrLn, stderr)
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revealFlateEncodedText :: ByteString -> ByteString
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revealFlateEncodedText =
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Lazy.toStrict . compress . revealText . decompress . Lazy.fromStrict
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where
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lines = Lazy.split '\n'
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unlines = Lazy.intercalate "\n"
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revealText = unlines . fmap fill . lines
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fill = update $ const Fill
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revealObject :: Object -> Object
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revealObject obj@(Stream {header, streamContent}) =
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case Map.lookup (Name "Filter") header of
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Just (NameObject (Name "FlateDecode")) ->
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let newStreamContent = revealFlateEncodedText streamContent in
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let newLength = Number . fromIntegral $ BS.length newStreamContent in
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Stream {
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header = Map.insert (Name "Length") (NumberObject newLength) header
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, streamContent = newStreamContent
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}
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_ -> obj
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revealObject obj = obj
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revealContent :: Content -> Content
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revealContent content = content {
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objects = revealObject <$> (objects content)
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}
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reveal :: Document -> Document
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reveal document = document {
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updates = revealContent <$> (updates document)
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}
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main :: IO ()
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main = do
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[inputPath, outputPath] <- getArgs
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result <- parseDocument <$> BS.readFile inputPath
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case result of
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Left parseError -> hPutStrLn stderr $ show parseError
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Right doc -> Lazy.writeFile outputPath . render $ reveal doc
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