Expose a toList function similar to Data.Map in module Id for IdMap and allow mapping over keys and values in a monadic construct like mapM

.gitignore

@@ -1,2 +1,3 @@
 dist*/
 .ghc.environment.*
+cabal.project.local

Hufflepdf.cabal

@@ -16,20 +16,40 @@ extra-source-files:  ChangeLog.md
 cabal-version:       >=1.10
 
 library
-  exposed-modules:     PDF
+  exposed-modules:     Data.OrderedMap
+                     , Data.Id
+                     , PDF
+                     , PDF.Box
+                     , PDF.CMap
+                     , PDF.Content
+                     , PDF.Content.Operator
+                     , PDF.Content.Operator.Color
+                     , PDF.Content.Operator.Common
+                     , PDF.Content.Operator.GraphicState
+                     , PDF.Content.Operator.Path
+                     , PDF.Content.Operator.Text
+                     , PDF.Content.Text
                      , PDF.EOL
+                     , PDF.Layer
                      , PDF.Object
+                     , PDF.Object.Navigation
                      , PDF.Output
-                     , PDF.Update
+                     , PDF.Parser
+                     , PDF.Pages
   other-modules:       Data.ByteString.Char8.Util
                      , PDF.Body
-                     , PDF.Parser
+                     , PDF.Encoding
+                     , PDF.Encoding.MacRoman
+                     , PDF.Font
   -- other-extensions:    
   build-depends:       attoparsec
                      , base >=4.9 && <4.13
                      , bytestring
                      , containers
                      , mtl
+                     , text
+                     , utf8-string
+                     , zlib
   hs-source-dirs:      src
   ghc-options:         -Wall
   default-language:    Haskell2010
@@ -39,7 +59,7 @@ executable             equivalent
   build-depends:       base
                      , bytestring
                      , Hufflepdf
-  ghc-options:         -Wall
+  ghc-options:         -Wall -rtsopts
   default-language:    Haskell2010
 
 executable             getObj
@@ -48,6 +68,63 @@ executable             getObj
                      , bytestring
                      , containers
                      , Hufflepdf
-                     , zlib
-  ghc-options:         -Wall
+                     , mtl
+  ghc-options:         -Wall -rtsopts
+  default-language:    Haskell2010
+
+executable             getText
+  main-is:             examples/getText.hs
+  build-depends:       base
+                     , bytestring
+                     , containers
+                     , ExceptIOH
+                     , Hufflepdf
+                     , mtl
+                     , text
+  ghc-options:         -Wall -rtsopts
+  default-language:    Haskell2010
+
+executable             pdfCut
+  main-is:             examples/pdfCut.hs
+  build-depends:       base
+                     , bytestring
+                     , containers
+                     , ExceptIOH
+                     , filepath
+                     , Hufflepdf
+                     , mtl
+                     , text
+  ghc-options:         -Wall -rtsopts
+  default-language:    Haskell2010
+
+executable             fixMermoz
+  main-is:             examples/fixMermoz.hs
+  build-depends:       base
+                     , bytestring
+                     , ExceptIOH
+                     , Hufflepdf
+                     , mtl
+  ghc-options:         -Wall -rtsopts
+  default-language:    Haskell2010
+
+Test-Suite unitTests
+  type:               exitcode-stdio-1.0
+  main-is:            Main.hs
+  other-modules:      Object
+                    , Data.ByteString.Char8.Util
+                    , Data.Id
+                    , PDF.EOL
+                    , PDF.Parser
+                    , PDF.Object
+                    , PDF.Output
+  hs-source-dirs:     test
+                    , src
+  build-depends:      attoparsec
+                    , base >=4.9 && <4.13
+                    , bytestring
+                    , containers
+                    , Hufflepdf
+                    , HUnit
+                    , mtl
+                    , text
   default-language:    Haskell2010

examples/getContent.hs

@@ -0,0 +1,11 @@
+main :: IO ()
+main = do
+  hSetBuffering stdout LineBuffering
+  args <- getArgs
+  case args of
+    --[inputFile] -> wholeDoc inputFile
+    [inputFile, pageNumber] -> do
+      content <- fmap (unify . updates) . parseDocument <$> BS.readFile inputFile
+      get content (read pageNumber)
+      singlePage inputFile (read pageNumber)
+    _ -> die "Syntax: getContent INPUT_FILE PAGE_NUMBER"

examples/getObj.hs

@@ -1,53 +1,52 @@
 {-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE FlexibleContexts #-}
 
-import Codec.Compression.Zlib (decompress)
+import Control.Monad.Reader (ReaderT, runReaderT)
 import Data.ByteString.Lazy.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as BS (readFile)
-import qualified Data.ByteString.Lazy.Char8 as Lazy (fromStrict, putStr, toStrict)
-import Data.Map ((!?))
-import qualified Data.Map as Map (keys, lookup)
+import qualified Data.ByteString.Lazy.Char8 as Lazy (putStrLn)
+import Data.Id (Id(..))
 import PDF (Document(..), parseDocument)
-import qualified PDF.EOL as EOL (Style)
-import PDF.Object (Content(..), DirectObject(..), Object(..), Name(..))
-import PDF.Output (ObjectId(..))
+import PDF.Box (Box(..))
+import PDF.Layer (Layer(..), unify)
+import PDF.Object (Object(..))
+import PDF.Object.Navigation (
+    Nav(..), PPath(..), StreamContent(..), (//), objectById, catalog
+  )
+import PDF.Output (Output)
 import qualified PDF.Output as Output (render)
-import PDF.Update (unify)
+import Prelude hiding (fail)
 import System.Environment (getArgs, getProgName)
 import System.Exit (die)
 import Text.Printf (printf)
+import Text.Read (readMaybe)
 
-display :: EOL.Style -> Object -> ByteString
-display eolStyle d@(Direct _) = Output.render eolStyle d
-display eolStyle s@(Stream {header, streamContent}) = Output.render eolStyle $
-  case Map.lookup (Name "Filter") header of
-    Just (NameObject (Name "FlateDecode")) -> Stream {
-          header
-        , streamContent = Lazy.toStrict . decompress $ Lazy.fromStrict streamContent
-      }
-    _ -> s
+decodedStream :: Object -> Object
+decodedStream object =
+  either (const object) id $ r Clear object >>= flip (w Raw) object
 
-extractObject :: ObjectId -> Document -> Either String ByteString
-extractObject objectId (Document {eolStyle, updates}) =
-  case objects content !? objectId of
-    Nothing -> Left $ "No object has ID " ++ show (getObjectId objectId)
-    Just o -> Right $ display eolStyle o
+display :: Functor m => Output a => ReaderT Layer m a -> Document -> m ByteString
+display getter (Document {eolStyle, layers}) =
+  Output.render eolStyle <$> runReaderT getter (unify layers)
+
+parse :: [String] -> IO (FilePath, Document -> Either String ByteString)
+parse [inputFile] = return (inputFile, display $ value <$> catalog)
+parse [inputFile, key] =
+  return (inputFile, clear . maybe (byPath key) byId $ readMaybe key)
   where
-    content = unify updates
-
-listObjectIds :: Document -> Either String [String]
-listObjectIds =
-  Right . prependTitle . toString . Map.keys . objects . unify . updates
-  where
-    toString = fmap (show . getObjectId)
-    prependTitle = ("ObjectIds defined in this PDF:":)
+    byId = objectById . Id
+    byPath path = (catalog // PPath (explode path))
+    explode "" = []
+    explode path =
+      case break (== '.') path of
+        (name, "") -> [name]
+        (name, rest) -> name : explode (drop 1 rest)
+    clear = display . fmap (decodedStream . value)
+parse _ =
+  die . printf "Syntax: %s inputFile [OBJECT_ID | PATH_TO_OBJ]\n" =<< getProgName
 
 main :: IO ()
 main = do
   (inputFile, getData) <- parse =<< getArgs
   input <- BS.readFile inputFile
-  either die id $ (parseDocument input >>= getData)
-  where
-    parse [inputFile] = return (inputFile, fmap (mapM_ putStrLn) . listObjectIds)
-    parse [inputFile, objectId] = return
-      (inputFile, fmap Lazy.putStr . extractObject (ObjectId (read objectId)))
-    parse _ = die . printf "Syntax: %s inputFile [OBJECT_ID]\n" =<< getProgName
+  either die Lazy.putStrLn $ (parseDocument input >>= getData)

examples/getText.hs

@@ -0,0 +1,54 @@
+{-# LANGUAGE FlexibleContexts #-}
+import Control.Monad ((>=>))
+import Control.Monad.Except (ExceptT(..))
+import Control.Monad.Except.IOH (handle)
+import Control.Monad.IO.Class (liftIO)
+import qualified Data.ByteString.Char8 as BS (readFile)
+import Data.Id (Id(..), mapWithKey)
+import qualified Data.Map as Map (mapWithKey)
+import Data.OrderedMap (mapi)
+import qualified Data.Text as Text (unpack)
+import PDF (UnifiedLayers(..), parseDocument)
+import PDF.Box (Box(..))
+import PDF.Content.Text (Chunks(..))
+import PDF.Layer (Layer, LayerReader)
+import PDF.Pages (
+      Contents(..), FontCache, Page(..), PageNumber(..), Pages(..), withFonts
+    , withResources
+  )
+import System.Environment (getArgs)
+import System.Exit (die)
+import System.IO (BufferMode(..), hSetBuffering, stdout)
+import Text.Printf (printf)
+
+displayPage :: Int -> Page -> FontCache (LayerReader (ExceptT String IO)) ()
+displayPage n = withResources (
+      r Contents
+    >=> sequence_ . mapi (\objectId ->
+            r Chunks >=> sequence_ . mapWithKey (display objectId)
+          )
+  )
+  where
+    display a b v =
+      liftIO . putStrLn $
+        printf "p#%d obj#%d instr#%d: %s" n (getId a) (getId b) (Text.unpack v)
+
+getAll :: Layer -> ExceptT String IO ()
+getAll = withFonts $ r Pages >=> sequence_ . Map.mapWithKey displayPage
+
+get :: Int -> Layer -> ExceptT String IO ()
+get n = withFonts $ r (P n) >=> displayPage n
+
+onDoc :: FilePath -> (Layer -> ExceptT String IO ()) -> ExceptT String IO ()
+onDoc inputFile f =
+  ExceptT (parseDocument <$> BS.readFile inputFile) >>= r UnifiedLayers >>= f
+
+main :: IO ()
+main = do
+  hSetBuffering stdout LineBuffering
+  args <- getArgs
+  case args of
+    [inputFile] -> onDoc inputFile getAll `handle` die
+    [inputFile, pageNumber] ->
+      onDoc inputFile (get $ read pageNumber) `handle` die
+    _ -> die "Syntax: getText INPUT_FILE [PAGE_NUMBER]"

examples/pdfCut.hs

@@ -0,0 +1,41 @@
+import Control.Monad.State (MonadState(..), evalStateT)
+import Control.Monad.Except.IOH (handle)
+import Control.Monad.Trans (lift)
+import qualified Data.ByteString.Char8 as BS (readFile)
+import qualified Data.ByteString.Lazy.Char8 as Lazy (writeFile)
+import Data.Map ((!), fromSet)
+import qualified Data.Set as Set (fromList)
+import PDF (Document, UnifiedLayers(..), parseDocument, render)
+import PDF.Box (at)
+import PDF.Pages (Pages(..))
+import System.Environment (getArgs)
+import System.Exit (die)
+import System.FilePath (replaceBaseName, takeBaseName)
+import Text.Read (readEither)
+
+parseRange :: String -> Either String (Int, Int)
+parseRange = evalStateT $ do
+  from <- lift . readEither =<< state (break (== '-'))
+  get >>= makeRange from
+  where
+    makeRange from "" = return (from, from)
+    makeRange from (_:to) = (,) from <$> lift (readEither to)
+
+cut :: (Int, Int) -> Document -> IO Document
+cut (p1, p2) doc = ((
+      at UnifiedLayers .at Pages $ \pages ->
+      return $ fromSet (pages!) $ Set.fromList [pMin .. pMax]
+    ) doc) `handle` die
+  where
+    (pMin, pMax) = (min p1 p2, max p1 p2)
+
+main :: IO ()
+main = do
+  [inputPath, inputRange] <- getArgs
+  range <- catchLeft $ parseRange inputRange
+  doc <- catchLeft =<< parseDocument <$> BS.readFile inputPath
+  Lazy.writeFile (outputPath inputPath inputRange) . render =<< cut range doc
+  where
+    catchLeft = either die return
+    outputPath fileName range =
+      replaceBaseName fileName (takeBaseName fileName ++ "_p" ++ range)

src/Data/ByteString/Char8/Util.hs

@@ -1,16 +1,91 @@
 module Data.ByteString.Char8.Util (
-      previous
+      B16Int(..)
+    , B256Int(..)
+    , b8ToInt
+    , b16ToBytes
+    , b16ToInt
+    , b256ToInt
+    , intToB256
+    , previous
     , subBS
+    , toBytes
+    , unescape
+    , utf16BEToutf8
   ) where
 
-import Data.ByteString.Char8 (ByteString)
-import qualified Data.ByteString.Char8 as BS (drop, index, take)
+import Data.ByteString (ByteString, snoc)
+import qualified Data.ByteString as BS (empty, foldl', length, pack, singleton, splitAt)
+import qualified Data.ByteString.Char8 as Char8 (
+    cons, drop, index, splitAt, take, uncons, unpack
+  )
+import Data.Text (Text)
+import Data.Text.Encoding (decodeUtf16BE)
 import Prelude hiding (length)
+import Text.Printf (printf)
+
+newtype B8Int = B8Int ByteString deriving (Eq, Show)
+newtype B16Int = B16Int ByteString deriving (Eq, Show)
+newtype B256Int = B256Int ByteString deriving (Eq, Show)
 
 previous :: Char -> Int -> ByteString -> Int
 previous char position byteString
-  | BS.index byteString position == char = position
+  | Char8.index byteString position == char = position
   | otherwise = previous char (position - 1) byteString
 
 subBS :: Int -> Int -> ByteString -> ByteString
-subBS offset length = BS.take length . BS.drop offset
+subBS offset length = Char8.take length . Char8.drop offset
+
+intToB256 :: Int -> B256Int
+intToB256 n
+  | n < 0x100 = B256Int . BS.singleton $ toEnum n
+  | otherwise =
+    let B256Int begining = intToB256 (n `div` 0x100) in
+    B256Int $ begining `snoc` (toEnum (n `mod` 0x100))
+
+b256ToInt :: B256Int -> Int
+b256ToInt (B256Int n) = BS.foldl' (\k w -> 0x100*k + fromEnum w) 0 n
+
+toBytes :: Int -> Int -> ByteString
+toBytes 0 _ = BS.empty
+toBytes size n =
+  (toBytes (size - 1) (n `div` 0x100)) `snoc` (toEnum (n `mod` 0x100))
+
+b16ToBytes :: B16Int -> ByteString
+b16ToBytes (B16Int n) = BS.pack . fmap b16ToInt $ pairDigits n
+  where
+    pairDigits s =
+      case BS.length s of
+        0 -> []
+        1 -> [B16Int s]
+        _ ->
+          let (twoHexDigits, rest) = BS.splitAt 2 s in
+          (B16Int $ twoHexDigits):(pairDigits rest)
+
+fromBase :: (Num a, Read a) => Char -> ByteString -> a
+fromBase b = read . printf "0%c%s" b . Char8.unpack
+
+b16ToInt :: (Num a, Read a) => B16Int -> a
+b16ToInt (B16Int n) = fromBase 'x' n
+
+b8ToInt :: (Num a, Read a) => B8Int -> a
+b8ToInt (B8Int n) = fromBase 'o' n
+
+unescape :: ByteString -> ByteString
+unescape escapedBS =
+  case Char8.uncons escapedBS of
+    Nothing -> BS.empty
+    Just ('\\', s) -> unescapeChar s
+    Just (c, s) -> Char8.cons c (unescape s)
+  where
+    unescapeChar s =
+      case Char8.uncons s of
+        Nothing -> BS.empty
+        Just (c, s')
+          | c `elem` "()" -> Char8.cons c (unescape s')
+          | c `elem` "nrtbf" -> Char8.cons (read (printf "'\\%c'" c)) (unescape s')
+          | c `elem` ['0'..'7'] -> fromOctal (Char8.splitAt 3 s)
+          | otherwise -> Char8.cons c (unescape s')
+    fromOctal (code, s) = Char8.cons (toEnum $ b8ToInt (B8Int code)) (unescape s)
+
+utf16BEToutf8 :: ByteString -> Text
+utf16BEToutf8 = decodeUtf16BE

src/Data/Id.hs

@@ -0,0 +1,95 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE DeriveTraversable #-}
+{-# LANGUAGE FlexibleContexts #-}
+module Data.Id (
+      Id(..)
+    , IdMap
+    , Indexed
+    , at
+    , delete
+    , empty
+    , filterWithKey
+    , fromList
+    , insert
+    , keysSet
+    , lookup
+    , mapWithKey
+    , member
+    , minViewWithKey
+    , register
+    , singleton
+    , size
+    , toList
+    , union
+  ) where
+
+import Control.Monad.State.Strict (MonadState, modify, gets)
+import Data.IntMap (IntMap, (!))
+import qualified Data.IntMap as IntMap (
+      delete, empty, filterWithKey, fromList, keysSet, insert, lookup, mapWithKey
+    , maxViewWithKey, member, minViewWithKey, size, toList, union
+  )
+import Data.IntSet (IntSet)
+import Prelude hiding (lookup)
+
+newtype Id a = Id {
+    getId :: Int
+  } deriving (Eq, Enum, Ord, Show)
+newtype IdMap a b = IdMap {
+    intMap :: IntMap b
+  } deriving (Show, Functor, Semigroup, Monoid, Foldable, Traversable)
+type Indexed a = IdMap a a
+
+at :: IdMap a b -> Id a -> b
+at (IdMap idMap) = (idMap !) . getId
+
+lookup :: Id a -> IdMap a b -> Maybe b
+lookup (Id a) (IdMap idMap) = IntMap.lookup a idMap
+
+size :: IdMap a b -> Int
+size = IntMap.size . intMap
+
+member :: Id a -> IdMap a b -> Bool
+member (Id a) (IdMap idMap) = IntMap.member a idMap
+
+empty :: IdMap a b
+empty = IdMap {intMap = IntMap.empty}
+
+singleton :: Id a -> b -> IdMap a b
+singleton a b = fromList [(a, b)]
+
+insert :: Id a -> b -> IdMap a b -> IdMap a b
+insert (Id a) b (IdMap idMap) = IdMap {intMap = IntMap.insert a b idMap}
+
+delete :: Id a -> IdMap a b -> IdMap a b
+delete (Id a) (IdMap idMap) = IdMap {intMap = IntMap.delete a idMap}
+
+minViewWithKey :: IdMap a b -> Maybe ((Id a, b), IdMap a b)
+minViewWithKey = fmap wrap . IntMap.minViewWithKey . intMap
+  where
+    wrap ((key, b), idMap) = ((Id key, b), IdMap idMap)
+
+union :: IdMap a b -> IdMap a b -> IdMap a b
+union (IdMap intMap1) (IdMap intMap2) =
+  IdMap {intMap = IntMap.union intMap1 intMap2}
+
+mapWithKey :: (Id a -> b -> c) -> IdMap a b -> IdMap a c
+mapWithKey f (IdMap idMap) = IdMap {intMap = IntMap.mapWithKey (f . Id) idMap}
+
+filterWithKey :: (Id a -> b -> Bool) -> IdMap a b -> IdMap a b
+filterWithKey f = IdMap . IntMap.filterWithKey (f . Id) . intMap
+
+fromList :: [(Id a, b)] -> IdMap a b
+fromList = IdMap . IntMap.fromList . fmap (\(key, b) -> (getId key, b))
+
+toList :: IdMap a b -> [(Id a, b)]
+toList = fmap (\(key, b) -> (Id key, b)) . IntMap.toList . intMap
+
+keysSet :: IdMap a b -> IntSet
+keysSet = IntMap.keysSet . intMap
+
+register :: MonadState (IdMap a b) m => b -> m (Id a)
+register b = do
+  newId <- gets (Id . maybe 0 ((+1) . fst . fst) . IntMap.maxViewWithKey . intMap)
+  modify (insert newId b)
+  return newId

src/Data/OrderedMap.hs

@@ -0,0 +1,79 @@
+{-# LANGUAGE NamedFieldPuns #-}
+module Data.OrderedMap (
+      OrderedMap
+    , build
+    , elems
+    , fromList
+    , get
+    , keys
+    , lookup
+    , mapi
+    , set
+    , toList
+  ) where
+
+import Data.Map (Map, (!), mapWithKey)
+import qualified Data.Map as Map (fromList, insert, lookup, member)
+import Prelude hiding (lookup)
+
+data OrderedMap k a = OrderedMap {
+      assoc :: Map k a
+    , keys :: [k]
+  } 
+
+instance (Ord k, Show k, Show a) => Show (OrderedMap k a) where
+  show = show . toList
+
+instance Functor (OrderedMap k) where
+  fmap f orderedMap = orderedMap {assoc = fmap f (assoc orderedMap)}
+
+instance Ord k => Foldable (OrderedMap k) where
+  foldMap f (OrderedMap {assoc, keys}) = foldMap f $ (assoc !) <$> keys
+
+instance Ord k => Traversable (OrderedMap k) where
+  sequenceA (OrderedMap {assoc, keys}) =
+    (flip OrderedMap keys) <$> sequenceA assoc 
+
+elems :: Ord k => OrderedMap k a -> [a]
+elems (OrderedMap {assoc, keys}) = (assoc !) <$> keys
+
+toList :: Ord k => OrderedMap k a -> [(k, a)]
+toList (OrderedMap {assoc, keys}) = (\k -> (k, assoc ! k)) <$> keys
+
+fromList :: Ord k => [(k, a)] -> OrderedMap k a
+fromList keyValueList = OrderedMap {
+      assoc = Map.fromList keyValueList
+    , keys = fst <$> keyValueList
+  }
+
+build :: Ord k => (k -> a) -> [k] -> OrderedMap k a
+build f keys = OrderedMap {
+      assoc = Map.fromList $ (\k -> (k, f k)) <$> keys
+    , keys
+  }
+
+get :: Ord k => k -> OrderedMap k a -> a
+get k = (! k) . assoc
+
+lookup :: Ord k => k -> OrderedMap k a -> Maybe a
+lookup k = (Map.lookup k) . assoc
+
+set :: Ord k => k -> a -> OrderedMap k a -> OrderedMap k a
+set k v orderedMap@(OrderedMap {assoc})
+  | Map.member k assoc = orderedMap {assoc = Map.insert k v assoc}
+  | otherwise = orderedMap
+
+mapi :: Ord k => (k -> a -> b) -> OrderedMap k a -> OrderedMap k b
+mapi f orderedMap = orderedMap {
+    assoc = mapWithKey f $ assoc orderedMap
+  }
+
+{-
+cons :: Ord k => k -> a -> OrderedMap k a -> OrderedMap k a
+cons k a orderedMap =
+
+snoc :: Ord k => k -> a -> OrderedMap k a -> OrderedMap k a
+
+alter :: Ord k => (Maybe a -> Maybe a) -> k -> OrderedMap k a -> OrderedMap k a
+alter 
+-}

src/PDF.hs

@@ -1,6 +1,11 @@
 {-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 module PDF (
       Document(..)
+    , EOLStyle(..)
+    , Layers(..)
+    , UnifiedLayers(..)
     , parseDocument
     , render
   ) where
@@ -13,27 +18,45 @@ import Data.ByteString.Char8.Util (previous, subBS)
 import qualified Data.ByteString.Lazy as Lazy (ByteString)
 import qualified Data.Map as Map (lookup)
 import PDF.Body (populate)
+import PDF.Box (Box(..))
 import qualified PDF.EOL as EOL (Style(..), charset, parser)
+import PDF.Layer (Layer, unify)
 import PDF.Object (
-      Content(..), DirectObject(..), InputStructure(..), Name(..), Number(..)
+      DirectObject(..), InputStructure(..), Name(..), Number(..)
     , Structure(..)
     , eofMarker, magicNumber, structure
   )
 import qualified PDF.Output as Output (render, line)
 import PDF.Output (Output(..))
-import PDF.Parser (Parser, runParser, string, takeAll)
+import PDF.Parser (Parser, evalParser, string, takeAll)
 import Text.Printf (printf)
 
 data Document = Document {
       pdfVersion :: String
     , eolStyle :: EOL.Style
-    , updates :: [Content]
+    , layers :: [Layer]
   } deriving Show
 
 instance Output Document where
-  output (Document {pdfVersion, updates}) =
+  output (Document {pdfVersion, layers}) =
       Output.line (printf "%%PDF-%s" pdfVersion)
-    `mappend` output updates
+    `mappend` output layers
+
+data EOLStyle = EOLStyle
+data Layers = Layers
+data UnifiedLayers = UnifiedLayers
+
+instance Monad m => Box m EOLStyle Document EOL.Style where
+  r EOLStyle = return . eolStyle
+  w EOLStyle eolStyle document = return $ document {eolStyle}
+
+instance Monad m => Box m UnifiedLayers Document Layer where
+  r UnifiedLayers = return . unify . layers
+  w UnifiedLayers layer = w Layers [layer]
+
+instance Monad m => Box m Layers Document [Layer] where
+  r Layers = return . layers
+  w Layers layers document = return $ document {layers = layers}
 
 render :: Document -> Lazy.ByteString
 render document@(Document {eolStyle}) = Output.render eolStyle document
@@ -83,7 +106,7 @@ findNextSection offset input =
 
 readStructures :: Int -> ByteString -> Either String [InputStructure]
 readStructures startXref input =
-  runParser structure () (BS.drop startXref input) >>= stopOrFollow
+  evalParser structure () (BS.drop startXref input) >>= stopOrFollow
   where
     stopOrFollow s@(Structure {trailer}) =
       case Map.lookup (Name "Prev") trailer of
@@ -96,8 +119,8 @@ readStructures startXref input =
 
 parseDocument :: ByteString -> Either String Document
 parseDocument input = do
-  (pdfVersion, eolStyle) <- runParser ((,) <$> version <*> EOL.parser) () input
+  (pdfVersion, eolStyle) <- evalParser ((,) <$> version <*> EOL.parser) () input
   startXref <- readStartXref eolStyle input
   structuresRead <- readStructures startXref input
-  let updates = populate input <$> structuresRead
-  return $ Document {pdfVersion, eolStyle, updates}
+  let layers = populate input <$> structuresRead
+  return $ Document {pdfVersion, eolStyle, layers}

src/PDF/Body.hs

@@ -6,19 +6,22 @@ module PDF.Body (
 
 import Control.Applicative ((<|>))
 import Control.Monad.State (get, gets, modify)
+import Data.Attoparsec.ByteString.Char8 (option)
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as BS (cons, drop, unpack)
-import Data.Map ((!))
-import qualified Data.Map as Map (empty, insert, lookup)
+import Data.Id (Id(..), at, empty)
+import qualified Data.Id as Id (insert, lookup)
+import qualified Data.Map as Map (lookup)
 import qualified PDF.EOL as EOL (charset, parser)
+import PDF.Layer (Layer(..))
 import PDF.Object (
-      Content(..), DirectObject(..), Flow(..), IndirectObjCoordinates(..)
+      DirectObject(..), Flow(..), IndirectObjCoordinates(..)
     , InputStructure(..), Name(..), Number(..), Object(..), Occurrence(..)
     , Structure(..), XRefEntry(..), XRefSection
     , blank, dictionary, directObject, integer, line
   )
-import PDF.Output (ObjectId(..), Offset(..))
-import PDF.Parser (Parser, (<?>), block, char, on, option, runParser, takeAll)
+import PDF.Output (Offset(..))
+import PDF.Parser (MonadParser(..), Parser, (<?>), evalParser, on)
 
 data UserState = UserState {
       input :: ByteString
@@ -31,9 +34,9 @@ type SParser = Parser UserState
 modifyFlow :: (Flow -> Flow) -> SParser ()
 modifyFlow f = modify $ \state -> state {flow = f $ flow state}
 
-addObject :: ObjectId -> Object -> SParser ()
+addObject :: (Id Object) -> Object -> SParser ()
 addObject objectId newObject = modifyFlow $ \flow -> flow {
-    tmpObjects = Map.insert objectId newObject $ tmpObjects flow
+    tmpObjects = Id.insert objectId newObject $ tmpObjects flow
   }
 
 pushOccurrence :: Occurrence -> SParser ()
@@ -46,10 +49,10 @@ comment = BS.unpack <$> (option "" afterPercent <* EOL.parser)
   where
     afterPercent = BS.cons <$> char '%' <*> takeAll (not . (`elem` EOL.charset))
 
-lookupOffset :: ObjectId -> SParser Offset
+lookupOffset :: (Id Object) -> SParser Offset
 lookupOffset objectId = do
   table <- gets xreferences
-  case Map.lookup objectId table >>= entryOffset of
+  case Id.lookup objectId table >>= entryOffset of
     Nothing -> fail $
       "obj " ++ show objectId ++ " is referenced but missing in XRef table"
     Just offset -> return offset
@@ -57,12 +60,12 @@ lookupOffset objectId = do
     entryOffset (InUse {offset}) = Just offset
     entryOffset _ = Nothing
 
-loadNumber :: ObjectId -> SParser Double
+loadNumber :: (Id Object) -> SParser Double
 loadNumber objectId = do
   offset <- getOffset <$> lookupOffset objectId
   objectStart <- BS.drop offset <$> gets input
   indirectObjCoordinates `on` (objectStart :: ByteString) >> return ()
-  objectValue <- (!objectId) . tmpObjects <$> gets flow
+  objectValue <- (`at` objectId) . tmpObjects <$> gets flow
   case objectValue of
     Direct (NumberObject (Number n)) -> return n
     obj -> fail $ "Expected obj@" ++ show offset ++ " (" ++ show obj ++ ") to be a Number"
@@ -75,7 +78,7 @@ getSize Nothing = fail "Missing '/Length' key on stream"
 getSize (Just (NumberObject (Number size))) = return size
 getSize (Just (Reference (IndirectObjCoordinates {objectId}))) = do
   Flow {tmpObjects} <- gets flow
-  case Map.lookup objectId tmpObjects of
+  case Id.lookup objectId tmpObjects of
     Nothing -> loadNumber objectId
     Just (Direct (NumberObject (Number size))) -> return size
     Just v -> fail $
@@ -96,7 +99,7 @@ object = streamObject <|> Direct <$> directObject
 
 indirectObjCoordinates :: SParser IndirectObjCoordinates
 indirectObjCoordinates = do
-  objectId <- ObjectId <$> integer
+  objectId <- Id <$> integer
   coordinates <- IndirectObjCoordinates objectId <$> integer
   objectValue <- line "obj" *> object <* blank <* line "endobj"
   addObject objectId objectValue
@@ -106,14 +109,14 @@ occurrence :: SParser Occurrence
 occurrence =
   Comment <$> comment <|> Indirect <$> indirectObjCoordinates <?> "comment or object"
 
-populate :: ByteString -> InputStructure -> Content
+populate :: ByteString -> InputStructure -> Layer
 populate input structure =
   let bodyInput = BS.drop (startOffset structure) input in
-  case runParser recurseOnOccurrences initialState bodyInput of
-    Left _ -> Content {occurrences = [], objects = Map.empty, docStructure}
+  case evalParser recurseOnOccurrences initialState bodyInput of
+    Left _ -> Layer {occurrences = [], objects = empty, docStructure}
     Right finalState ->
       let Flow {occurrencesStack, tmpObjects} = flow finalState in
-      Content {
+      Layer {
           occurrences = reverse occurrencesStack, objects = tmpObjects, docStructure
         }
   where
@@ -121,7 +124,7 @@ populate input structure =
     xreferences = xRef docStructure
     initialState = UserState {
         input, xreferences, flow = Flow {
-            occurrencesStack = [], tmpObjects = Map.empty
+            occurrencesStack = [], tmpObjects = empty
           }
       }
 

src/PDF/Box.hs

@@ -0,0 +1,80 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+module PDF.Box (
+      Box(..)
+    , Index(..)
+    , Maybe_(..)
+    , Either_(..)
+    , at
+    , atAll
+    , edit
+    , runRO
+  ) where
+
+import Control.Monad.Except (ExceptT(..), runExceptT)
+import Control.Monad.Fail (MonadFail(..))
+import Control.Monad.Reader (ReaderT, runReaderT)
+import Control.Monad.State (MonadState(..))
+import Data.Id (Id, IdMap)
+import qualified Data.Id as Id (insert, lookup)
+import Data.Map (Map)
+import qualified Data.Map as Map (insert, lookup)
+import Data.OrderedMap (OrderedMap)
+import qualified Data.OrderedMap as OrderedMap (lookup, set)
+import Prelude hiding (fail)
+
+runRO :: MonadState s m => ReaderT s m a -> m a
+runRO ro = get >>= runReaderT ro
+
+newtype Index = Index Int
+newtype Maybe_ x = Maybe_ x
+newtype Either_ b x = Either_ x
+
+class Monad m => Box m i a b | m a i -> b where
+  r :: i -> a -> m b
+  w :: i -> b -> a -> m a
+
+at :: Box m i a b => i -> (b -> m b) -> a -> m a
+at i f a = r i a >>= f >>= flip (w i) a
+
+atAll :: (Traversable t, Monad m, Box m i a (t b)) => i -> (b -> m b) -> a -> m a
+atAll i f = at i $ (mapM f)
+
+edit :: MonadState a m => (a -> m a) -> m ()
+edit f = get >>= f >>= put
+
+instance MonadFail m => Box m Index [a] a where
+  r (Index i) [] = fail $ "Index out of bounds " ++ show i
+  r (Index 0) (x:_) = return x
+  r (Index i) (_:xs) = r (Index (i-1)) xs
+
+  w (Index i) _ [] = fail $ "Index out of bounds " ++ show i
+  w (Index 0) newX (_:xs) = return (newX:xs)
+  w (Index i) newX (x:xs) = (x:) <$> w (Index (i-1)) newX xs
+
+instance (Ord k, MonadFail m) => Box m k (Map k a) a where
+  r k = maybe (fail "Unknown key") return . Map.lookup k
+  w k a = return . Map.insert k a
+
+instance (Ord k, MonadFail m) => Box m k (OrderedMap k a) a where
+  r k = maybe (fail "Unknown key") return . OrderedMap.lookup k
+  w k a orderedMap = r k orderedMap >> return (OrderedMap.set k a orderedMap)
+
+instance MonadFail m => Box m (Id k) (IdMap k a) a where
+  r k = maybe (fail "Unknown key") return . Id.lookup k
+  w k a = return . Id.insert k a
+
+instance (Monad m, Box Maybe i a b) => Box m (Maybe_ i) a (Maybe b) where
+  r (Maybe_ i) = return . r i
+  w (Maybe_ i) (Just b) a =
+    return . maybe a id $ w i b a
+  w _ _ obj = return obj
+
+instance (Monad m, Box (ExceptT e m) i a b) => Box m (Either_ e i) a (Either e b) where
+  r (Either_ i) a = runExceptT (r i a)
+  w (Either_ i) (Right b) a =
+    either (const a) id <$> runExceptT (w i b a :: ExceptT e m a)
+  w _ _ a = return a

src/PDF/CMap.hs

@@ -0,0 +1,196 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE FlexibleContexts #-}
+module PDF.CMap (
+      CMap
+    , CMappers
+    , CRange(..)
+    , matches
+    , parse
+  ) where
+
+import Control.Applicative ((<|>), many)
+import Control.Monad.Except (MonadError(..))
+import Control.Monad.Fail (fail)
+import Control.Monad.State (modify)
+import Data.Attoparsec.ByteString.Char8 (count)
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS (drop, length, null, take)
+import Data.ByteString.Char8 (unpack)
+import Data.ByteString.Char8.Util (
+    B16Int(..), b16ToBytes, b16ToInt, toBytes, utf16BEToutf8
+  )
+import Data.Foldable (foldl', foldr')
+import Data.Map (Map, mapWithKey, union)
+import qualified Data.Map as Map (
+    adjust, empty, fromList, insert, insertWith, lookup, toList
+  )
+import Data.Text (Text)
+import qualified Data.Text as Text (length, null, splitAt)
+import qualified PDF.EOL as EOL (charset, parser)
+import PDF.Font (Decoder, Encoder, Font(..))
+import PDF.Object (
+      DirectObject(..), Name, StringObject(..)
+    , blank, directObject, integer, line, stringObject
+  )
+import PDF.Parser (MonadParser, Parser, runParser, takeAll)
+import Prelude hiding (fail)
+
+type CMappers = Map Name CMap
+type ToUnicode = Map ByteString Text
+type FromUnicode = Map Text ByteString
+data CRange = CRange {
+      fromSequence :: ByteString
+    , toSequence :: ByteString
+    , toUnicode :: ToUnicode
+  } deriving Show
+type Size = Int
+data CMap = CMap {
+      toUnicodeBySize :: Map Size [CRange]
+    , fromUnicodeBySize :: Map Size FromUnicode
+  }
+
+toFont :: CMap -> Font
+toFont (CMap {toUnicodeBySize, fromUnicodeBySize})  =
+  Font {decode = decoder toUnicodeBySize, encode = encoder fromUnicodeBySize}
+
+decoder :: Map Size [CRange] -> Decoder
+decoder rangesBySize input
+  | BS.null input = Right ""
+  | otherwise = do
+    (output, remainingInput) <- trySizes input $ Map.toList rangesBySize
+    mappend output <$> decoder rangesBySize remainingInput
+  where
+    trySizes s [] = Left $ "No matching code found in font for " ++ unpack s
+    trySizes s ((size, cRanges):others) =
+      let prefix = BS.take size s in
+      case tryRanges prefix cRanges of
+        Nothing -> trySizes s others
+        Just outputSequence -> Right (outputSequence, BS.drop size s)
+    tryRanges :: ByteString -> [CRange] -> Maybe Text
+    tryRanges _ [] = Nothing
+    tryRanges prefix ((CRange {toUnicode}):cRanges) =
+      case Map.lookup prefix toUnicode of
+        Nothing -> tryRanges prefix cRanges
+        outputSequence -> outputSequence
+
+encoder :: Map Size FromUnicode -> Encoder
+encoder fromUnicodes input
+  | Text.null input = Right ""
+  | otherwise =
+    foldr' (<>) (Left "No encoding found") $ mapWithKey tryOn fromUnicodes
+    where
+      tryOn size fromUnicode =
+        let (prefix, end) = Text.splitAt size input in
+        case Map.lookup prefix fromUnicode of
+          Nothing -> Left ""
+          Just code -> (code <>) <$> encoder fromUnicodes end
+
+matches :: ByteString -> CRange -> Bool
+matches code (CRange {fromSequence, toSequence}) =
+  fromSequence <= code && code <= toSequence
+
+parse :: MonadError String m => ByteString -> m Font
+parse = either throwError (return . toFont . snd) . runParser
+  (many (codeRanges <|> cMapRange <|> cMapChar <|> ignoredLine))
+  emptyCMap
+  where
+    ignoredLine =
+      takeAll (not . (`elem` EOL.charset)) *> EOL.parser *> return ()
+    emptyCMap = CMap {toUnicodeBySize = Map.empty, fromUnicodeBySize = Map.empty}
+
+codeRanges :: Parser CMap ()
+codeRanges = do
+  size <- integer <* line "begincodespacerange"
+  mapM_ createMapping =<< count size codeRange
+  line "endcodespacerange"
+  where
+    codeRange =
+      (,) <$> stringObject <* blank <*> stringObject <* EOL.parser
+
+createMapping :: (StringObject, StringObject) -> Parser CMap ()
+createMapping (Hexadecimal from, Hexadecimal to) = modify $ \cmap -> cmap {
+      toUnicodeBySize = Map.insertWith (++) size [cRange] (toUnicodeBySize cmap)
+    }
+  where
+    fromSequence = b16ToBytes from
+    size = BS.length fromSequence
+    toSequence = b16ToBytes to
+    cRange = CRange {fromSequence, toSequence, toUnicode = Map.empty}
+createMapping _ = return ()
+
+cMapRange :: Parser CMap ()
+cMapRange = do
+  size <- integer <* line "beginbfrange"
+  mapM_ saveMapping =<< count size rangeMapping
+  line "endbfrange"
+  where
+    rangeMapping = do
+      from <- (stringObject <* blank)
+      to <- (stringObject <* blank)
+      mapFromTo from to =<< directObject <* EOL.parser
+
+saveMapping :: [(ByteString, Text)] -> Parser CMap ()
+saveMapping assoc =
+  modify $ \(CMap {toUnicodeBySize, fromUnicodeBySize}) -> CMap {
+        toUnicodeBySize = saveToUnicodeBySize assoc toUnicodeBySize
+      , fromUnicodeBySize = saveFromUnicodeBySize reversed fromUnicodeBySize
+    }
+    where
+      reversed = (\(a, b) -> (b, a)) <$> assoc
+
+saveToUnicodeBySize :: [(ByteString, Text)] -> Map Size [CRange] -> Map Size [CRange]
+saveToUnicodeBySize [] = id
+saveToUnicodeBySize assoc@((code, _):_) = Map.adjust insertCRange (BS.length code)
+  where
+    newMapping = Map.fromList assoc
+    appendMapping cRange =
+      cRange {toUnicode = toUnicode cRange `union` newMapping}
+    insertCRange = fmap (\cRange ->
+        if code `matches` cRange then appendMapping cRange else cRange
+      )
+
+saveFromUnicodeBySize :: [(Text, ByteString)] -> Map Size FromUnicode -> Map Size FromUnicode
+saveFromUnicodeBySize = flip (foldl' insertFromUnicode)
+  where
+    insertFromUnicode :: Map Size FromUnicode -> (Text, ByteString) -> Map Size FromUnicode
+    insertFromUnicode tmpFromUnicodeBySize (unicodeSequence, code) =
+      let size = Text.length unicodeSequence in
+      Map.adjust (Map.insert unicodeSequence code) size tmpFromUnicodeBySize
+
+cMapChar :: Parser CMap ()
+cMapChar = do
+  size <- integer <* line "beginbfchar"
+  saveMapping =<< count size charMapping <* line "endbfchar"
+  where
+    charMapping = do
+      from <- stringObject <* blank
+      pairMapping from =<< stringObject <* EOL.parser
+
+between :: B16Int -> B16Int -> [ByteString]
+between from@(B16Int s) to =
+  let size = BS.length s `div` 2 in
+  toBytes size <$> [b16ToInt from .. b16ToInt to]
+
+startFrom :: B16Int -> [ByteString]
+startFrom from@(B16Int s) =
+  let size = BS.length s `div` 2 in
+  toBytes size <$> [b16ToInt from .. ]
+
+mapFromTo :: MonadParser m => StringObject -> StringObject -> DirectObject -> m [(ByteString, Text)]
+mapFromTo (Hexadecimal from) (Hexadecimal to) (StringObject (Hexadecimal dstFrom)) =
+  return $ zip (between from to) (utf16BEToutf8 <$> startFrom dstFrom)
+
+mapFromTo (Hexadecimal from) (Hexadecimal to) (Array dstPoints) =
+  zip (between from to) <$> (mapM dstByteString dstPoints)
+  where
+    dstByteString (StringObject (Hexadecimal dst)) =
+      return . utf16BEToutf8 $ b16ToBytes dst
+    dstByteString _ = fail "Invalid for a replacement string"
+
+mapFromTo _ _ _ = fail "invalid range mapping found"
+
+pairMapping :: MonadParser m => StringObject -> StringObject -> m (ByteString, Text)
+pairMapping (Hexadecimal from) (Hexadecimal to) =
+  return (b16ToBytes  from, utf16BEToutf8 $ b16ToBytes  to)
+pairMapping _ _ = fail "invalid pair mapping found"

src/PDF/Content.hs

@@ -0,0 +1,117 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+module PDF.Content (
+      Content(..)
+    , ContentUnit(..)
+    , GraphicContextUnit(..)
+    , IdContentUnit
+    , IdGraphicContextUnit
+    , IdTextContext
+    , Instructions(..)
+    , TextContext
+    , parse
+  ) where
+
+import Control.Applicative ((<|>))
+import Control.Monad.Reader (asks, runReader)
+import Control.Monad.State.Strict (runState, evalStateT, modify)
+import Data.Attoparsec.ByteString.Char8 (sepBy)
+import qualified Data.Attoparsec.ByteString.Char8 as Atto (Parser, parseOnly)
+import Data.ByteString (ByteString)
+import Data.Id (Id(..), Indexed, at, empty, register)
+import PDF.Box (Box(..))
+import PDF.Content.Operator (Instruction, operator)
+import PDF.Object (blank, directObject)
+import PDF.Output (Output(..), line)
+import PDF.Parser (string)
+
+data Instructions = Instructions
+
+data GraphicContextUnit a =
+    GraphicInstruction a
+  | ContentUnit (ContentUnit a)
+  deriving Show
+type TextContext a = [a]
+data ContentUnit a =
+    GraphicContext [GraphicContextUnit a]
+  | TextContext (TextContext a)
+  deriving Show
+data Content = Content {
+      contentUnits :: [IdContentUnit]
+    , indexedInstructions :: Indexed Instruction
+    , firstError :: Maybe String
+  } deriving Show
+
+type TmpContentUnit = ContentUnit Instruction
+type TmpGraphicContextUnit = GraphicContextUnit Instruction
+type TmpTextContext = TextContext Instruction
+
+type IdContentUnit = ContentUnit (Id Instruction)
+type IdGraphicContextUnit = GraphicContextUnit (Id Instruction)
+type IdTextContext = TextContext (Id Instruction)
+
+instance Monad m => Box m Instructions Content (Indexed Instruction) where
+  r Instructions = return . indexedInstructions
+  w Instructions indexedInstructions someContent =
+    return $ someContent {indexedInstructions}
+
+parse :: ByteString -> Content
+parse input =
+  let result = Atto.parseOnly (contentUnit `sepBy` blank) input in
+  let (contentUnits, indexedInstructions) = either (const ([], empty)) buildContent result in
+  let firstError = either Just (const Nothing) result in
+  Content {contentUnits, indexedInstructions, firstError}
+
+buildContent :: [TmpContentUnit] -> ([IdContentUnit], Indexed Instruction)
+buildContent instructionContentUnits =
+  runState (mapM registerContentUnit instructionContentUnits) empty
+  where
+    registerContentUnit (GraphicContext gc) =
+      GraphicContext <$> (mapM registerGraphicContext gc)
+    registerContentUnit (TextContext tc) = TextContext <$> (mapM register tc)
+    registerGraphicContext (GraphicInstruction gi) =
+      GraphicInstruction <$> (register gi)
+    registerGraphicContext (ContentUnit cu) =
+      ContentUnit <$> (registerContentUnit cu)
+
+contentUnit :: Atto.Parser TmpContentUnit
+contentUnit =
+    (GraphicContext <$> graphicContext)
+  <|> (TextContext <$> textContext)
+  where
+    graphicContext =
+      string "q" *> blank *> graphicContextUnit `sepBy` blank <* blank <* string "Q"
+
+graphicContextUnit :: Atto.Parser TmpGraphicContextUnit
+graphicContextUnit =
+    (GraphicInstruction <$> instruction)
+  <|> (ContentUnit <$> contentUnit)
+
+instruction :: Atto.Parser Instruction
+instruction = evalStateT stackParser []
+  where
+    stackParser = ((directObject <* blank) >>= push) <|> operator
+    push arg = modify (arg:) *> stackParser
+
+textContext :: Atto.Parser TmpTextContext
+textContext =
+  string "BT" *> blank *> instruction `sepBy` blank <* blank <* string "ET"
+
+instance Output Content where
+  output (Content {contentUnits, indexedInstructions}) =
+    runReader (mconcat <$> mapM outputCU contentUnits) indexedInstructions
+    where
+      outputCU (GraphicContext gc) = do
+        inside <- mconcat <$> mapM outputGCU gc
+        return (line "q" `mappend` inside `mappend` line "Q")
+      outputCU (TextContext tc) = do
+        inside <- mconcat <$> mapM outputIId tc
+        return (line "BT" `mappend` inside `mappend` line "ET")
+      outputGCU (GraphicInstruction gi) = outputIId gi
+      outputGCU (ContentUnit cu) = outputCU cu
+      outputIId instructionId = asks (output . (`at` instructionId))

src/PDF/Content/Operator.hs

@@ -0,0 +1,76 @@
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
+module PDF.Content.Operator (
+      Instruction
+    , Operator(..)
+    , operator
+  ) where
+
+import Control.Monad.Fail (MonadFail(..))
+import Control.Monad.State (MonadState(..))
+import Data.ByteString.Char8 (ByteString, pack, unpack)
+import Data.Char (toLower)
+import Data.Map (Map)
+import qualified Data.Map as Map (fromList, lookup)
+import qualified PDF.Content.Operator.Color as Color (Operator, signature)
+import PDF.Content.Operator.Common (Signature)
+import qualified PDF.Content.Operator.GraphicState as GraphicState (Operator, signature)
+import qualified PDF.Content.Operator.Path as Path (Operator, signature)
+import qualified PDF.Content.Operator.Text as Text (Operator, signature)
+import PDF.Object (DirectObject, blank, regular)
+import PDF.Output (Output(..), join, line)
+import PDF.Parser (MonadParser, takeAll1)
+import Prelude hiding (fail)
+import Text.Printf (printf)
+
+data Operator =
+    GraphicState GraphicState.Operator
+  | Path Path.Operator
+  | Color Color.Operator
+  | Text Text.Operator 
+
+instance Show Operator where
+  show (GraphicState gcOp) = code gcOp
+  show (Path pOp) = code pOp
+  show (Color cOp) = code cOp
+  show (Text tOp) = code tOp
+
+type Instruction = (Operator, [DirectObject])
+
+instance Output Instruction where
+  output (op, args) = join " " ((output <$> args) ++ [line (show op)])
+
+operatorsTable :: Map ByteString (Signature Operator)
+operatorsTable = Map.fromList (
+      (prepare GraphicState <$> GraphicState.signature)
+    ++ (prepare Path <$> Path.signature)
+    ++ (prepare Color <$> Color.signature)
+    ++ (prepare Text <$> Text.signature)
+  )
+  where
+    prepare constructor (op, sig) = (pack $ code op, (constructor op, sig))
+
+code :: Show a => a -> String
+code = expand . show
+  where
+    expand "" = ""
+    expand (c:'_':s) = toLower c : expand s
+    expand ('s':'t':'a':'r':s) = '*' : expand s
+    expand ('Q':'u':'o':'t':'e':s) = '\'' : expand s
+    expand ('D':'Q':'u':'o':'t':'e':s) = '"' : expand s
+    expand (c:s) = c : expand s
+
+type StackParser m = (MonadState [DirectObject] m, MonadParser m)
+
+operator :: StackParser m => m Instruction
+operator = do
+  chunk <- takeAll1 regular <* blank
+  args <- reverse <$> get
+  case Map.lookup chunk operatorsTable of
+    Just (op, sig)
+      | sig args -> return (op, args)
+      | otherwise -> 
+        get >>= fail . printf "Operator %s with stack %s" (show op) . show
+    _ -> fail ("Unknown chunk " ++ unpack chunk)

src/PDF/Content/Operator/Color.hs

@@ -0,0 +1,27 @@
+module PDF.Content.Operator.Color (
+      Operator(..)
+    , signature
+  ) where
+
+import PDF.Content.Operator.Common (Signature)
+import PDF.Object (DirectObject(..))
+
+data Operator =
+    CS | C_s | SC | SCN | S_c | S_cn | G | G_ | RG | R_g | K | K_
+  deriving (Bounded, Enum, Show)
+
+signature :: [Signature Operator]
+signature = [
+      (CS, \l -> case l of [NameObject _] -> True ; _ -> False)
+    , (C_s, \l -> case l of [NameObject _] -> True ; _ -> False)
+    , (SC, \_ -> True)
+    , (SCN, \_ -> True)
+    , (S_c, \_ -> True)
+    , (S_cn, \_ -> True)
+    , (G, \l -> case l of [_] -> True ; _ -> False)
+    , (G_, \l -> case l of [_] -> True ; _ -> False)
+    , (RG, \l -> case l of [_, _, _] -> True ; _ -> False)
+    , (R_g, \l -> case l of [_, _, _] -> True ; _ -> False)
+    , (K, \l -> case l of [_, _, _, _] -> True ; _ -> False)
+    , (K_, \l -> case l of [_, _, _, _] -> True ; _ -> False)
+  ]

src/PDF/Content/Operator/Common.hs

@@ -0,0 +1,7 @@
+module PDF.Content.Operator.Common (
+    Signature
+  ) where
+
+import PDF.Object (DirectObject)
+
+type Signature a = (a, [DirectObject] -> Bool)

src/PDF/Content/Operator/GraphicState.hs

@@ -0,0 +1,24 @@
+module PDF.Content.Operator.GraphicState (
+      Operator(..)
+    , signature
+  ) where
+
+import PDF.Content.Operator.Common (Signature)
+import PDF.Object (DirectObject(..))
+
+data Operator =
+  C_m | W_ | J | J_ | M | D_ | R_i | I_ | G_s -- general graphic state
+  deriving (Bounded, Enum, Show)
+
+signature :: [Signature Operator]
+signature = [
+      (C_m, \l -> case l of [_, _, _, _, _, _] -> True ; _ -> False)
+    , (W_, \l -> case l of [_] -> True ; _ -> False)
+    , (J, \l -> case l of [_] -> True ; _ -> False)
+    , (J_, \l -> case l of [_] -> True ; _ -> False)
+    , (M, \l -> case l of [_] -> True ; _ -> False)
+    , (D_, \l -> case l of [_, _] -> True ; _ -> False)
+    , (R_i, \l -> case l of [_] -> True ; _ -> False)
+    , (I_, \l -> case l of [_] -> True ; _ -> False)
+    , (G_s, \l -> case l of [NameObject _] -> True ; _ -> False)
+  ]

src/PDF/Content/Operator/Path.hs

@@ -0,0 +1,35 @@
+module PDF.Content.Operator.Path (
+      Operator(..)
+    , signature
+  ) where
+
+import PDF.Content.Operator.Common (Signature)
+
+data Operator =
+    M_ | L_ | C_ | V_ | Y_ | H_ | R_e -- path construction
+  | S | S_ | F_ | F | Fstar | B | Bstar | B_ | B_star | N_ -- path painting
+  | W | Wstar -- clipping path
+  deriving (Bounded, Enum, Show)
+
+signature :: [Signature Operator]
+signature = [
+      (M_, \l -> case l of [_, _] -> True ; _ -> False)
+    , (L_, \l -> case l of [_, _] -> True ; _ -> False)
+    , (C_, \l -> case l of [_, _, _, _, _, _] -> True ; _ -> False)
+    , (V_, \l -> case l of [_, _, _, _] -> True ; _ -> False)
+    , (Y_, \l -> case l of [_, _, _, _] -> True ; _ -> False)
+    , (H_, \l -> case l of [] -> True ; _ -> False)
+    , (R_e, \l -> case l of [_, _, _, _] -> True ; _ -> False)
+    , (S, \l -> case l of [] -> True ; _ -> False)
+    , (S_, \l -> case l of [] -> True ; _ -> False)
+    , (F_, \l -> case l of [] -> True ; _ -> False)
+    , (F, \l -> case l of [] -> True ; _ -> False)
+    , (Fstar, \l -> case l of [] -> True ; _ -> False)
+    , (B, \l -> case l of [] -> True ; _ -> False)
+    , (Bstar, \l -> case l of [] -> True ; _ -> False)
+    , (B_, \l -> case l of [] -> True ; _ -> False)
+    , (B_star, \l -> case l of [] -> True ; _ -> False)
+    , (N_, \l -> case l of [] -> True ; _ -> False)
+    , (W, \l -> case l of [] -> True ; _ -> False)
+    , (Wstar, \l -> case l of [] -> True ; _ -> False)
+  ]

src/PDF/Content/Operator/Text.hs

@@ -0,0 +1,32 @@
+module PDF.Content.Operator.Text (
+      Operator(..)
+    , signature
+  ) where
+
+import PDF.Content.Operator.Common (Signature)
+import PDF.Object (DirectObject(..))
+
+data Operator =
+    Td | TD | Tm | Tstar -- text positioning
+  | TJ | Tj | Quote | DQuote -- text showing
+  | Tc | Tw | Tz | TL | Tf | Tr | Ts -- text state
+  deriving (Bounded, Enum, Show)
+
+signature :: [Signature Operator]
+signature = [
+      (Td, \l -> case l of [_, _] -> True ; _ -> False)
+    , (TD, \l -> case l of [_, _] -> True ; _ -> False)
+    , (Tm, \l -> case l of [_, _, _, _, _, _] -> True ; _ -> False)
+    , (Tstar, \l -> case l of [] -> True ; _ -> False)
+    , (TJ, \l -> case l of [Array _] -> True ; _ -> False)
+    , (Tj, \l -> case l of [StringObject _] -> True ; _ -> False)
+    , (Quote, \l -> case l of [StringObject _] -> True ; _ -> False)
+    , (DQuote, \l -> case l of [_, _, StringObject _] -> True ; _ -> False)
+    , (Tc, \l -> case l of [_] -> True ; _ -> False)
+    , (Tw, \l -> case l of [_] -> True ; _ -> False)
+    , (Tz, \l -> case l of [_] -> True ; _ -> False)
+    , (TL, \l -> case l of [_] -> True ; _ -> False)
+    , (Tf, \l -> case l of [NameObject _, _] -> True ; _ -> False)
+    , (Tr, \l -> case l of [_] -> True ; _ -> False)
+    , (Ts, \l -> case l of [_] -> True ; _ -> False)
+  ]

src/PDF/Content/Text.hs

@@ -0,0 +1,151 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+module PDF.Content.Text (
+      Chunks(..)
+    , chunk
+    , format
+  ) where
+
+import Control.Monad (foldM)
+import Control.Monad.Fail (MonadFail(..))
+import Control.Monad.Reader (ReaderT, asks, runReaderT)
+import Control.Monad.State (
+    MonadState(..), StateT, evalStateT, gets, modify, runStateT
+  )
+import Control.Monad.Trans (lift)
+import qualified Data.ByteString.Char8 as BS (concatMap, singleton)
+import Data.Id (Id(..), Indexed, at, empty, singleton)
+import qualified Data.Id as Id (delete, lookup, register)
+import Data.Map ((!))
+import Data.Text (Text, breakOn)
+import qualified Data.Text as Text (drop)
+import PDF.Box (Box(..))
+import PDF.Content (
+      Content(..), ContentUnit(..), GraphicContextUnit(..), IdContentUnit
+    , IdGraphicContextUnit
+  )
+import PDF.Content.Operator (Instruction, Operator(..))
+import PDF.Content.Operator.Text (Operator(..))
+import PDF.Font (Font(..), FontSet, emptyFont)
+import PDF.Object (DirectObject(..), StringObject(..), toByteString)
+import Prelude hiding (fail)
+
+type TmpFont = StateT Font
+type Renderer m = ReaderT (Indexed Instruction) (ReaderT FontSet m)
+type Updater m = StateT (Indexed Instruction) (ReaderT (Indexed Text) (ReaderT FontSet m))
+
+decodeString :: MonadFail m => StringObject -> TmpFont (Renderer m) Text
+decodeString input = do
+  Font {decode} <- get
+  either fail return . decode $ toByteString input
+
+data Chunks = Chunks
+
+chunk :: Int -> Id Text
+chunk = Id
+
+instance MonadFail m => Box (ReaderT FontSet m) Chunks Content (Indexed Text) where
+  r Chunks content =
+    runReaderT (mconcat <$> renderer) $ indexedInstructions content
+    where
+      renderer = mapM renderContentUnit (contentUnits content)
+
+  w Chunks indexedText content = do
+    (contentUnits, indexedInstructions) <- runReaderT readerUpdate indexedText
+    return $ content {contentUnits, indexedInstructions}
+    where
+      stateUpdate = mapM updateContentUnit (contentUnits content)
+      readerUpdate = runStateT stateUpdate (indexedInstructions content)
+
+renderContentUnit :: MonadFail m => IdContentUnit -> Renderer m (Indexed Text)
+renderContentUnit (GraphicContext graphicContextUnits) =
+  mconcat <$> mapM renderGraphicContextUnit graphicContextUnits
+renderContentUnit (TextContext instructionIds) =
+  evalStateT (mconcat <$> mapM renderInstructionId instructionIds) emptyFont
+
+updateContentUnit :: MonadFail m => IdContentUnit -> Updater m IdContentUnit
+updateContentUnit (GraphicContext graphicContextUnits) = GraphicContext <$>
+  mapM updateGraphicContextUnit graphicContextUnits
+updateContentUnit (TextContext instructionIds) = TextContext . concat <$>
+  evalStateT (mapM updateInstructionId instructionIds) emptyFont
+
+renderGraphicContextUnit :: MonadFail m => IdGraphicContextUnit -> Renderer m (Indexed Text)
+renderGraphicContextUnit (GraphicInstruction _) = return empty
+renderGraphicContextUnit (ContentUnit contentUnit) =
+  renderContentUnit contentUnit
+
+updateGraphicContextUnit :: MonadFail m => IdGraphicContextUnit -> Updater m IdGraphicContextUnit
+updateGraphicContextUnit gI@(GraphicInstruction _) = return gI
+updateGraphicContextUnit (ContentUnit contentUnit) =
+  ContentUnit <$> updateContentUnit contentUnit
+
+renderInstructionId :: MonadFail m => Id Instruction -> TmpFont (Renderer m) (Indexed Text)
+renderInstructionId instructionId@(Id n) = toMap <$>
+  (asks ((`at` instructionId)) >>= renderInstruction)
+  where
+    toMap = maybe empty (singleton (Id n))
+
+updateInstructionId :: MonadFail m => Id Instruction -> TmpFont (Updater m) [Id Instruction]
+updateInstructionId instructionId =
+  lift (gets (`at` instructionId)) >>= updateInstruction instructionId
+
+renderInstruction :: MonadFail m => Instruction -> TmpFont (Renderer m) (Maybe Text)
+renderInstruction (Text Tf, [NameObject fontName, _]) =
+  lift (lift $ asks (! fontName)) >>= put >> return Nothing
+
+renderInstruction (Text Tstar, []) = return $ Just "\n"
+
+renderInstruction (Text TJ, [Array arrayObject]) =
+  Just <$> foldM appendText "" arrayObject
+  where
+    appendText t (StringObject outputString) =
+      mappend t <$> decodeString outputString
+    appendText t _ = return t
+
+renderInstruction (Text Tj, [StringObject outputString]) =
+  Just <$> decodeString outputString
+
+renderInstruction (Text Quote, [StringObject outputString]) =
+  (Just . mappend "\n") <$> decodeString outputString
+
+renderInstruction (Text DQuote, [_, _, StringObject outputString]) =
+  (Just . mappend "\n") <$> decodeString outputString
+
+renderInstruction _ = return Nothing
+
+updateInstruction :: MonadFail m => Id Instruction -> Instruction -> TmpFont (Updater m) [Id Instruction]
+updateInstruction instructionId (Text Tf, [NameObject fontName, _]) =
+  (lift . lift . lift $ asks (!fontName)) >>= put >> return [instructionId]
+
+updateInstruction instructionId@(Id n) instruction = do
+  if emitsText $ fst instruction
+  then asks (Id.lookup (Id n)) >>= replaceText
+  else return [instructionId]
+  where
+    emitsText (Text Tstar) = True
+    emitsText (Text TJ) = True
+    emitsText (Text Tj) = True
+    emitsText (Text Quote) = True
+    emitsText (Text DQuote) = True
+    emitsText _ = False
+    replaceText = maybe (return []) $ \text -> do
+      lift $ modify (Id.delete instructionId)
+      format text >>= mapM (lift . Id.register)
+
+format :: MonadFail m => Text -> StateT Font m [Instruction]
+format input = do
+  case breakOn "\n" input of
+    ("", "") -> return []
+    ("", left) -> ((Text Tstar, []) :) <$> format (Text.drop 1 left)
+    (line, left) -> (:) <$> tj line <*> format left
+  where
+    tj t = do
+      encoded <- either fail return =<< gets (($t) . encode)
+      return (Text Tj, [StringObject . Literal $ BS.concatMap escape encoded])
+    escape '\\' = "\\\\"
+    escape '(' = "\\("
+    escape ')' = "\\)"
+    escape c = BS.singleton c

src/PDF/EOL.hs

@@ -6,14 +6,14 @@ module PDF.EOL (
   ) where
 
 import Control.Applicative ((<|>))
-import PDF.Parser (Parser, string)
+import PDF.Parser (MonadParser, string)
 
 data Style = CR | LF | CRLF deriving Show
 
 charset :: String
 charset = "\r\n"
 
-parser :: Parser s Style
+parser :: MonadParser m => m Style
 parser =
     (string "\r\n" >> return CRLF)
   <|> (string "\r" >> return CR)

src/PDF/Encoding.hs

@@ -0,0 +1,13 @@
+{-# LANGUAGE FlexibleContexts #-}
+module PDF.Encoding (
+    encoding
+  ) where
+
+import Control.Monad.Except (MonadError(..))
+import PDF.Encoding.MacRoman (macRomanEncoding)
+import PDF.Font (Font)
+import Prelude hiding (fail)
+
+encoding :: MonadError String m => String -> m Font
+encoding "MacRomanEncoding" = return macRomanEncoding
+encoding s = throwError $ "Unknown encoding " ++ s

src/PDF/Encoding/MacRoman.hs

@@ -0,0 +1,162 @@
+module PDF.Encoding.MacRoman (
+    macRomanEncoding
+  ) where
+
+import qualified Data.ByteString.Char8 as BS (pack, unpack)
+import Data.Foldable (foldl')
+import Data.Map (Map)
+import qualified Data.Map as Map (empty, insert, lookup)
+import qualified Data.Text as Text (pack, unpack)
+import PDF.Font (Font(..))
+
+type Mapper = Map Char Char
+macRomanEncoding :: Font
+macRomanEncoding = Font {
+      decode = Right . Text.pack . fmap decodeChar . BS.unpack
+    , encode = fmap BS.pack . mapM encodeChar . Text.unpack
+  }
+  where
+    decodeChar k = maybe k id $ Map.lookup k (fst mappers)
+    encodeChar k =
+      case Map.lookup k (snd mappers) of
+        Just v -> Right v
+        Nothing
+          | k < '\x80' -> Right k
+          | otherwise -> Left ("Character '" ++ k :"' unavailable in MacRoman")
+
+mappers :: (Mapper, Mapper)
+mappers = foldl' generateMapers (Map.empty, Map.empty) [
+      ('\x80', '\x00C4') -- LATIN CAPITAL LETTER A WITH DIAERESIS
+    , ('\x81', '\x00C5') -- LATIN CAPITAL LETTER A WITH RING ABOVE
+    , ('\x82', '\x00C7') -- LATIN CAPITAL LETTER C WITH CEDILLA
+    , ('\x83', '\x00C9') -- LATIN CAPITAL LETTER E WITH ACUTE
+    , ('\x84', '\x00D1') -- LATIN CAPITAL LETTER N WITH TILDE
+    , ('\x85', '\x00D6') -- LATIN CAPITAL LETTER O WITH DIAERESIS
+    , ('\x86', '\x00DC') -- LATIN CAPITAL LETTER U WITH DIAERESIS
+    , ('\x87', '\x00E1') -- LATIN SMALL LETTER A WITH ACUTE
+    , ('\x88', '\x00E0') -- LATIN SMALL LETTER A WITH GRAVE
+    , ('\x89', '\x00E2') -- LATIN SMALL LETTER A WITH CIRCUMFLEX
+    , ('\x8A', '\x00E4') -- LATIN SMALL LETTER A WITH DIAERESIS
+    , ('\x8B', '\x00E3') -- LATIN SMALL LETTER A WITH TILDE
+    , ('\x8C', '\x00E5') -- LATIN SMALL LETTER A WITH RING ABOVE
+    , ('\x8D', '\x00E7') -- LATIN SMALL LETTER C WITH CEDILLA
+    , ('\x8E', '\x00E9') -- LATIN SMALL LETTER E WITH ACUTE
+    , ('\x8F', '\x00E8') -- LATIN SMALL LETTER E WITH GRAVE
+    , ('\x90', '\x00EA') -- LATIN SMALL LETTER E WITH CIRCUMFLEX
+    , ('\x91', '\x00EB') -- LATIN SMALL LETTER E WITH DIAERESIS
+    , ('\x92', '\x00ED') -- LATIN SMALL LETTER I WITH ACUTE
+    , ('\x93', '\x00EC') -- LATIN SMALL LETTER I WITH GRAVE
+    , ('\x94', '\x00EE') -- LATIN SMALL LETTER I WITH CIRCUMFLEX
+    , ('\x95', '\x00EF') -- LATIN SMALL LETTER I WITH DIAERESIS
+    , ('\x96', '\x00F1') -- LATIN SMALL LETTER N WITH TILDE
+    , ('\x97', '\x00F3') -- LATIN SMALL LETTER O WITH ACUTE
+    , ('\x98', '\x00F2') -- LATIN SMALL LETTER O WITH GRAVE
+    , ('\x99', '\x00F4') -- LATIN SMALL LETTER O WITH CIRCUMFLEX
+    , ('\x9A', '\x00F6') -- LATIN SMALL LETTER O WITH DIAERESIS
+    , ('\x9B', '\x00F5') -- LATIN SMALL LETTER O WITH TILDE
+    , ('\x9C', '\x00FA') -- LATIN SMALL LETTER U WITH ACUTE
+    , ('\x9D', '\x00F9') -- LATIN SMALL LETTER U WITH GRAVE
+    , ('\x9E', '\x00FB') -- LATIN SMALL LETTER U WITH CIRCUMFLEX
+    , ('\x9F', '\x00FC') -- LATIN SMALL LETTER U WITH DIAERESIS
+    , ('\xA0', '\x2020') -- DAGGER
+    , ('\xA1', '\x00B0') -- DEGREE SIGN
+    , ('\xA2', '\x00A2') -- CENT SIGN
+    , ('\xA3', '\x00A3') -- POUND SIGN
+    , ('\xA4', '\x00A7') -- SECTION SIGN
+    , ('\xA5', '\x2022') -- BULLET
+    , ('\xA6', '\x00B6') -- PILCROW SIGN
+    , ('\xA7', '\x00DF') -- LATIN SMALL LETTER SHARP S
+    , ('\xA8', '\x00AE') -- REGISTERED SIGN
+    , ('\xA9', '\x00A9') -- COPYRIGHT SIGN
+    , ('\xAA', '\x2122') -- TRADE MARK SIGN
+    , ('\xAB', '\x00B4') -- ACUTE ACCENT
+    , ('\xAC', '\x00A8') -- DIAERESIS
+    , ('\xAD', '\x2260') -- NOT EQUAL TO
+    , ('\xAE', '\x00C6') -- LATIN CAPITAL LETTER AE
+    , ('\xAF', '\x00D8') -- LATIN CAPITAL LETTER O WITH STROKE
+    , ('\xB0', '\x221E') -- INFINITY
+    , ('\xB1', '\x00B1') -- PLUS-MINUS SIGN
+    , ('\xB2', '\x2264') -- LESS-THAN OR EQUAL TO
+    , ('\xB3', '\x2265') -- GREATER-THAN OR EQUAL TO
+    , ('\xB4', '\x00A5') -- YEN SIGN
+    , ('\xB5', '\x00B5') -- MICRO SIGN
+    , ('\xB6', '\x2202') -- PARTIAL DIFFERENTIAL
+    , ('\xB7', '\x2211') -- N-ARY SUMMATION
+    , ('\xB8', '\x220F') -- N-ARY PRODUCT
+    , ('\xB9', '\x03C0') -- GREEK SMALL LETTER PI
+    , ('\xBA', '\x222B') -- INTEGRAL
+    , ('\xBB', '\x00AA') -- FEMININE ORDINAL INDICATOR
+    , ('\xBC', '\x00BA') -- MASCULINE ORDINAL INDICATOR
+    , ('\xBD', '\x03A9') -- GREEK CAPITAL LETTER OMEGA
+    , ('\xBE', '\x00E6') -- LATIN SMALL LETTER AE
+    , ('\xBF', '\x00F8') -- LATIN SMALL LETTER O WITH STROKE
+    , ('\xC0', '\x00BF') -- INVERTED QUESTION MARK
+    , ('\xC1', '\x00A1') -- INVERTED EXCLAMATION MARK
+    , ('\xC2', '\x00AC') -- NOT SIGN
+    , ('\xC3', '\x221A') -- SQUARE ROOT
+    , ('\xC4', '\x0192') -- LATIN SMALL LETTER F WITH HOOK
+    , ('\xC5', '\x2248') -- ALMOST EQUAL TO
+    , ('\xC6', '\x2206') -- INCREMENT
+    , ('\xC7', '\x00AB') -- LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
+    , ('\xC8', '\x00BB') -- RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
+    , ('\xC9', '\x2026') -- HORIZONTAL ELLIPSIS
+    , ('\xCA', '\x00A0') -- NO-BREAK SPACE
+    , ('\xCB', '\x00C0') -- LATIN CAPITAL LETTER A WITH GRAVE
+    , ('\xCC', '\x00C3') -- LATIN CAPITAL LETTER A WITH TILDE
+    , ('\xCD', '\x00D5') -- LATIN CAPITAL LETTER O WITH TILDE
+    , ('\xCE', '\x0152') -- LATIN CAPITAL LIGATURE OE
+    , ('\xCF', '\x0153') -- LATIN SMALL LIGATURE OE
+    , ('\xD0', '\x2013') -- EN DASH
+    , ('\xD1', '\x2014') -- EM DASH
+    , ('\xD2', '\x201C') -- LEFT DOUBLE QUOTATION MARK
+    , ('\xD3', '\x201D') -- RIGHT DOUBLE QUOTATION MARK
+    , ('\xD4', '\x2018') -- LEFT SINGLE QUOTATION MARK
+    , ('\xD5', '\x2019') -- RIGHT SINGLE QUOTATION MARK
+    , ('\xD6', '\x00F7') -- DIVISION SIGN
+    , ('\xD7', '\x25CA') -- LOZENGE
+    , ('\xD8', '\x00FF') -- LATIN SMALL LETTER Y WITH DIAERESIS
+    , ('\xD9', '\x0178') -- LATIN CAPITAL LETTER Y WITH DIAERESIS
+    , ('\xDA', '\x2044') -- FRACTION SLASH
+    , ('\xDB', '\x20AC') -- EURO SIGN
+    , ('\xDC', '\x2039') -- SINGLE LEFT-POINTING ANGLE QUOTATION MARK
+    , ('\xDD', '\x203A') -- SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
+    , ('\xDE', '\xFB01') -- LATIN SMALL LIGATURE FI
+    , ('\xDF', '\xFB02') -- LATIN SMALL LIGATURE FL
+    , ('\xE0', '\x2021') -- DOUBLE DAGGER
+    , ('\xE1', '\x00B7') -- MIDDLE DOT
+    , ('\xE2', '\x201A') -- SINGLE LOW-9 QUOTATION MARK
+    , ('\xE3', '\x201E') -- DOUBLE LOW-9 QUOTATION MARK
+    , ('\xE4', '\x2030') -- PER MILLE SIGN
+    , ('\xE5', '\x00C2') -- LATIN CAPITAL LETTER A WITH CIRCUMFLEX
+    , ('\xE6', '\x00CA') -- LATIN CAPITAL LETTER E WITH CIRCUMFLEX
+    , ('\xE7', '\x00C1') -- LATIN CAPITAL LETTER A WITH ACUTE
+    , ('\xE8', '\x00CB') -- LATIN CAPITAL LETTER E WITH DIAERESIS
+    , ('\xE9', '\x00C8') -- LATIN CAPITAL LETTER E WITH GRAVE
+    , ('\xEA', '\x00CD') -- LATIN CAPITAL LETTER I WITH ACUTE
+    , ('\xEB', '\x00CE') -- LATIN CAPITAL LETTER I WITH CIRCUMFLEX
+    , ('\xEC', '\x00CF') -- LATIN CAPITAL LETTER I WITH DIAERESIS
+    , ('\xED', '\x00CC') -- LATIN CAPITAL LETTER I WITH GRAVE
+    , ('\xEE', '\x00D3') -- LATIN CAPITAL LETTER O WITH ACUTE
+    , ('\xEF', '\x00D4') -- LATIN CAPITAL LETTER O WITH CIRCUMFLEX
+    , ('\xF0', '\xF8FF') -- Apple logo
+    , ('\xF1', '\x00D2') -- LATIN CAPITAL LETTER O WITH GRAVE
+    , ('\xF2', '\x00DA') -- LATIN CAPITAL LETTER U WITH ACUTE
+    , ('\xF3', '\x00DB') -- LATIN CAPITAL LETTER U WITH CIRCUMFLEX
+    , ('\xF4', '\x00D9') -- LATIN CAPITAL LETTER U WITH GRAVE
+    , ('\xF5', '\x0131') -- LATIN SMALL LETTER DOTLESS I
+    , ('\xF6', '\x02C6') -- MODIFIER LETTER CIRCUMFLEX ACCENT
+    , ('\xF7', '\x02DC') -- SMALL TILDE
+    , ('\xF8', '\x00AF') -- MACRON
+    , ('\xF9', '\x02D8') -- BREVE
+    , ('\xFA', '\x02D9') -- DOT ABOVE
+    , ('\xFB', '\x02DA') -- RING ABOVE
+    , ('\xFC', '\x00B8') -- CEDILLA
+    , ('\xFD', '\x02DD') -- DOUBLE ACUTE ACCENT
+    , ('\xFE', '\x02DB') -- OGONEK
+    , ('\xFF', '\x02C7') -- CARON
+  ]
+  where
+    generateMapers (tmpDecoder, tmpEncoder) (macChar, utf8Char) = (
+          Map.insert macChar utf8Char tmpDecoder
+        , Map.insert utf8Char macChar tmpEncoder
+      )

src/PDF/Font.hs

@@ -0,0 +1,27 @@
+module PDF.Font (
+      Decoder
+    , Encoder
+    , Font(..)
+    , FontSet
+    , emptyFont
+  ) where
+
+import Data.ByteString (ByteString)
+import Data.Map (Map)
+import Data.Text (Text)
+import PDF.Object (Name)
+
+type Decoder = ByteString -> Either String Text
+type Encoder = Text -> Either String ByteString
+data Font = Font {
+      decode :: Decoder
+    , encode :: Encoder
+  }
+
+type FontSet = Map Name Font
+
+emptyFont :: Font
+emptyFont = Font {
+      decode = \_ -> Left "No fond loaded"
+    , encode = \_ -> Left "No fond loaded"
+  }

src/PDF/Layer.hs

@@ -0,0 +1,129 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleContexts #-}
+module PDF.Layer (
+      Layer(..)
+    , LayerReader
+    , Objects(..)
+    , unify
+  ) where
+
+import Control.Monad.Except (MonadError(..))
+import Control.Monad.Reader (ReaderT)
+import Data.Foldable (foldl')
+import Data.Id (Id(..), Indexed, keysSet, mapWithKey, member)
+import qualified Data.Id as Id (empty, insert, lookup, union)
+import Data.Map (Map, (!))
+import qualified Data.Map as Map (empty, lookup, union)
+import qualified Data.IntSet as IntSet (delete, toList)
+import PDF.Box (Box(..))
+import PDF.Object (
+      IndirectObjCoordinates(..), Object, Occurrence(..), Structure(..)
+    , XRefEntry(..), XRefSection, eofMarker, outputBody
+  )
+import qualified PDF.Output as Output (line)
+import PDF.Output (
+      Offset(..), Output(..), Resource(..), byteString, getOffset
+    , getOffsets, newLine
+  )
+import Text.Printf (printf)
+
+data Layer = Layer {
+      occurrences :: [Occurrence]
+    , objects :: Indexed Object
+    , docStructure :: Structure
+  } deriving Show
+type LayerReader m = ReaderT Layer m
+
+updateXRefs :: XRefSection -> Map Resource Offset -> (XRefSection, Offset)
+updateXRefs xRef offsets = (mapWithKey updateEntry xRef, offsets ! StartXRef)
+  where
+    updateEntry objectId e@(InUse {offset}) =
+      case Map.lookup (ObjectId $ getId objectId) offsets of
+        Nothing -> Free {nextFree = Id $ getOffset offset, generation = 65535}
+        Just newOffset -> e {offset = newOffset}
+    updateEntry _ e = e
+
+instance Output Layer where
+  output (Layer {occurrences, objects, docStructure}) = do
+    (body, savedOffsets) <- getOffsets (outputBody (occurrences, objects))
+    let (newXRef, startXRef) = updateXRefs xRef savedOffsets
+    mconcat [
+          return body
+        , Output.line "xref"
+        , output newXRef
+        , Output.line "trailer"
+        , output trailer, newLine
+        , Output.line "startxref"
+        , Output.line (printf "%d" (getOffset startXRef))
+        , byteString eofMarker
+      ]
+    where
+      Structure {xRef, trailer} = docStructure
+
+data Objects = Objects
+
+instance Monad m => Box m Objects Layer (Indexed Object) where
+  r Objects = return . objects
+  w Objects newObjects layer@(Layer {occurrences, docStructure}) =
+    return $ layer {
+          occurrences = keptOccurrences ++ newOccurrences
+        , objects = newObjects
+        , docStructure = docStructure {
+              xRef = (const $ InUse (Offset 0) 0) <$> newObjects
+            }
+      }
+    where
+      filterOccurrences c@(Comment _) (occ, newObjIds) = (c:occ, newObjIds)
+      filterOccurrences i@(Indirect (IndirectObjCoordinates {objectId})) (occ, newObjIds)
+        | member objectId newObjects = (i:occ, IntSet.delete (getId objectId) newObjIds)
+        | otherwise = (occ, newObjIds)
+      (keptOccurrences, newObjectIds) =
+        foldr filterOccurrences ([], keysSet newObjects) occurrences
+      makeOccurrence objectId =
+        Indirect (IndirectObjCoordinates {objectId, versionNumber = 0})
+      newOccurrences = (makeOccurrence . Id) <$> IntSet.toList newObjectIds
+
+instance MonadError String m => Box m (Id Object) Layer Object where
+  r objectId =
+    maybe (throwError "Unknown key") return . Id.lookup objectId . objects
+  w objectId a layer@(Layer {objects})
+    | member objectId objects = return $
+      layer {objects = Id.insert objectId a objects}
+    | otherwise = throwError "Unknown key"
+
+emptyLayer :: Layer
+emptyLayer = Layer {
+      docStructure = Structure {xRef = Id.empty, trailer = Map.empty}
+    , objects = Id.empty
+    , occurrences = []
+  }
+
+unify :: [Layer] -> Layer
+unify = foldl' complete emptyLayer
+  where
+    complete tmpLayer older =
+      let mergedObjects = Id.union (objects tmpLayer) (objects older) in
+      Layer {
+          docStructure =
+            unifyDocStructure (docStructure tmpLayer) (docStructure older)
+        , objects = mergedObjects
+        , occurrences =
+            unifyOccurrences mergedObjects (occurrences tmpLayer) (occurrences older)
+      }
+
+unifyDocStructure :: Structure -> Structure -> Structure
+unifyDocStructure new old = Structure {
+      xRef = Id.union (xRef new) (xRef old)
+    , trailer = Map.union (trailer new) (trailer old)
+  }
+
+unifyOccurrences :: (Indexed Object) -> [Occurrence] -> [Occurrence] -> [Occurrence]
+unifyOccurrences objects new = foldr addOlder new
+  where
+    addOlder occurrence@(Comment _) existing = occurrence : existing
+    addOlder occurrence@(Indirect indirect) existing =
+      if objectId indirect `member` objects
+      then occurrence : existing
+      else existing

src/PDF/Object.hs

@@ -2,19 +2,20 @@
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE FlexibleInstances #-}
 module PDF.Object (
-      Content(..)
+      Dictionary
     , DirectObject(..)
     , Flow(..)
-    , IndexedObjects
     , IndirectObjCoordinates(..)
     , InputStructure(..)
     , Name(..)
     , Number(..)
     , Object(..)
     , Occurrence(..)
+    , StringObject(..)
     , Structure(..)
     , XRefEntry(..)
     , XRefSection
+    , array
     , blank
     , dictionary
     , directObject
@@ -22,34 +23,43 @@ module PDF.Object (
     , integer
     , line
     , magicNumber
+    , name
+    , number
+    , object
+    , outputBody
+    , regular
+    , stringObject
     , structure
+    , toByteString
   ) where
 
-import Control.Applicative ((<|>))
-import Data.ByteString.Char8 (ByteString)
-import qualified Data.ByteString.Char8 as BS (
-    concat, cons, pack, singleton, unpack
+import Control.Applicative ((<|>), many)
+import Control.Monad.Reader (asks)
+import Data.Attoparsec.ByteString.Char8 (choice, count, option, sepBy)
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS (concat)
+import qualified Data.ByteString.Char8 as Char8 (
+    cons, length, pack, singleton, snoc, unpack
   )
-import Data.Map (Map, (!), mapWithKey)
-import qualified Data.Map as Map (
-    delete, empty, fromList, lookup, minViewWithKey, toList, union
+import Data.ByteString.Char8.Util (B16Int(..), b16ToBytes, unescape)
+import Data.Id (Id(..), IdMap, Indexed)
+import qualified Data.Id as Id (
+    at, delete, empty, fromList, lookup, minViewWithKey, union
   )
-import qualified PDF.EOL as EOL (charset, parser)
-import qualified PDF.Output as Output (concat, line, string)
+import Data.Map (Map)
+import qualified Data.Map as Map (fromList, toList)
+import qualified Data.Set as Set (fromList, member)
+import qualified PDF.EOL as EOL (Style(..), charset, parser)
+import qualified PDF.Output as Output (line, string)
 import PDF.Output (
-      OBuilder, ObjectId(..), Offset(..), Output(..), Resource(..)
-    , byteString, getObjectId, getOffset, getOffsets, join, newLine
-    , saveOffset
-  )
-import PDF.Parser (
-      Parser, (<?>)
-    , char, choice, count, decNumber, hexNumber, many, octDigit, oneOf, option
-    , sepBy, string, takeAll, takeAll1
+      OBuilder, OContext(..), Offset(..), Output(..), Resource(..), byteString
+    , getOffset, join, newLine, saveOffset
   )
+import PDF.Parser (MonadParser(..), Parser, (<?>), octDigit, oneOf)
 import Text.Printf (printf)
 
-line :: String -> Parser u ()
-line l = (string (BS.pack l) *> blank *> return ()) <?> printf "line «%s»" l
+line :: MonadParser m => String -> m ()
+line l = (string (Char8.pack l) *> blank *> return ()) <?> printf "line «%s»" l
 
 magicNumber :: ByteString
 magicNumber = "%PDF-"
@@ -60,8 +70,8 @@ eofMarker = "%%EOF"
 whiteSpaceCharset :: String
 whiteSpaceCharset = "\0\t\12 "
 
-blank :: Parser u ()
-blank = takeAll (`elem` (EOL.charset ++ whiteSpaceCharset)) *> return ()
+blank :: MonadParser m => m ()
+blank = takeAll (`elem` (EOL.charset ++ whiteSpaceCharset)) *> pure ()
 
 delimiterCharset :: String
 delimiterCharset = "()<>[]{}/%"
@@ -69,26 +79,24 @@ delimiterCharset = "()<>[]{}/%"
 regular :: Char -> Bool
 regular = not . (`elem` (EOL.charset ++ whiteSpaceCharset ++ delimiterCharset))
 
-integer :: (Read a, Num a) => Parser u a
-integer = read . BS.unpack <$> decNumber <* blank <?> "decimal integer"
+integer :: MonadParser m => m Int
+integer = decNumber <* blank <?> "decimal integer"
 
 -------------------------------------
 --          OBJECTS
 -------------------------------------
 
-type IndexedObjects = Map ObjectId Object
-
 --
 -- Boolean
 --
-boolean :: Parser u Bool
+boolean :: MonadParser m => m Bool
 boolean =
   (string "true" *> return True) <|> (string "false" *> return False) <?> "boolean"
 
 --
 -- Number
 --
-newtype Number = Number Double deriving Show
+newtype Number = Number Double deriving (Eq, Show)
 
 instance Output Number where
   output (Number f) = Output.string $
@@ -96,38 +104,44 @@ instance Output Number where
       (n, 0) -> printf "%d" (n :: Int)
       _ -> printf "%f" f
 
-number :: Parser u Number
-number = Number . read . BS.unpack <$>
-  (mappend <$> sign <*> (integerPart <|> BS.cons '0' <$> floatPart))
-  <?> "number"
+number :: MonadParser m => m Number
+number = Number <$> (sign <*> value) <?> "number"
   where
-    sign = string "-" <|> option "" (char '+' >> return "")
-    integerPart = mappend <$> decNumber <*> option "" floatPart
-    floatPart = BS.cons <$> char '.' <*> (option "0" $ decNumber)
+    sign = (string "-" *> return negate) <|> option id (char '+' >> return id)
+    value = floatNumber <|> (char '.' *> afterPoint)
+    afterPoint = read . ("0." ++) . Char8.unpack <$> takeAll (`Set.member` digits)
+    digits = Set.fromList ['0' .. '9']
 
 --
 -- StringObject
 --
-data StringObject = Literal String | Hexadecimal String deriving Show
+data StringObject = Literal ByteString | Hexadecimal B16Int deriving (Eq, Show)
 
 instance Output StringObject where
-  output (Literal s) = Output.string (printf "(%s)" s)
-  output (Hexadecimal s) = Output.string (printf "<%s>" s)
+  output (Literal s) = Output.string (printf "(%s)" (Char8.unpack s))
+  output (Hexadecimal (B16Int n)) = Output.string (printf "<%s>" (Char8.unpack n))
 
-stringObject :: Parser u StringObject
+stringObject :: MonadParser m => m StringObject
 stringObject =
-    Literal . BS.unpack <$> (char '(' *> (BS.concat <$> literalString) <* char ')')
-  <|> Hexadecimal . BS.unpack <$> (char '<' *> hexNumber <* char '>')
+    Literal <$> (char '(' *> (BS.concat <$> literalString) <* char ')')
+  <|> Hexadecimal . roundBytes <$> (char '<' *> hexNumber <* char '>')
   <?> "string object (literal or hexadecimal)"
   where
     literalString = many literalStringBlock
     literalStringBlock = takeAll1 normalChar <|> matchingParenthesis <|> escapedChar
     normalChar = not . (`elem` ("\\()" :: String))
     matchingParenthesis =
-      mappend <$> (BS.cons <$> char '(' <*> literalStringBlock) <*> string ")"
+      mappend <$> (Char8.cons <$> char '(' <*> literalStringBlock) <*> string ")"
     escapedChar =
-      BS.cons <$> char '\\' <*> (BS.singleton <$> oneOf "nrtbf()\\" <|> octalCode)
-    octalCode = choice $ (\n -> BS.pack <$> count n octDigit) <$> [1..3]
+      Char8.cons <$> char '\\' <*> (Char8.singleton <$> oneOf "nrtbf()\\\n" <|> octalCode)
+    octalCode = choice $ (\n -> Char8.pack <$> count n octDigit) <$> [1..3]
+    roundBytes (B16Int bs)
+      | Char8.length bs `mod` 2 == 1 = B16Int (bs `Char8.snoc` '0')
+      | otherwise = B16Int bs
+
+toByteString :: StringObject -> ByteString
+toByteString (Hexadecimal h) = b16ToBytes h
+toByteString (Literal s) = unescape s
 
 --
 -- Name
@@ -137,13 +151,13 @@ newtype Name = Name String deriving (Eq, Ord, Show)
 instance Output Name where
   output (Name n) = Output.string ('/':n)
 
-name :: Parser u Name
-name = Name . BS.unpack <$> (char '/' *> takeAll regular) <?> "name"
+name :: MonadParser m => m Name
+name = Name . Char8.unpack <$> (char '/' *> takeAll regular) <?> "name"
 
 --
 -- Array
 --
-array :: Parser u [DirectObject]
+array :: MonadParser m => m [DirectObject]
 array =
   char '[' *> blank *> directObject `sepBy` blank <* blank <* char ']' <?> "array"
 
@@ -153,14 +167,14 @@ array =
 type Dictionary = Map Name DirectObject
 
 instance Output Dictionary where
-  output dict =
+  output aDictionary =
     "<<" `mappend` keyValues `mappend` ">>"
     where
-      keyValues = join " " $ outputKeyVal <$> Map.toList dict
+      keyValues = join " " $ outputKeyVal <$> Map.toList aDictionary
       outputKeyVal :: (Name, DirectObject) -> OBuilder
-      outputKeyVal (key, val) = Output.concat [output key, " ", output val]
+      outputKeyVal (key, val) = mconcat [output key, " ", output val]
 
-dictionary :: Parser u Dictionary
+dictionary :: MonadParser m => m Dictionary
 dictionary =
   string "<<" *> blank *> keyValPairs <* string ">>" <?> "dictionary"
   where
@@ -170,33 +184,33 @@ dictionary =
 --
 -- Null
 --
-nullObject :: Parser u ()
+nullObject :: MonadParser m => m ()
 nullObject = string "null" *> return () <?> "null object"
 
 --
 -- Reference
 --
 data IndirectObjCoordinates = IndirectObjCoordinates {
-      objectId :: ObjectId
-    , versionNumber :: Int
+      objectId :: {-# UNPACK #-} !(Id Object)
+    , versionNumber :: {-# UNPACK #-} !Int
   } deriving Show
 
-reference :: Parser u IndirectObjCoordinates
+reference :: MonadParser m => m IndirectObjCoordinates
 reference = IndirectObjCoordinates
-  <$> (fmap ObjectId integer) <*> integer <* char 'R' <?> "reference to an object"
+  <$> (fmap Id integer) <*> integer <* char 'R' <?> "reference to an object"
 
 --
 -- DirectObject
 --
 data DirectObject =
-    Boolean Bool
-  | NumberObject Number
-  | StringObject StringObject
-  | NameObject Name
-  | Array [DirectObject]
-  | Dictionary Dictionary
+    Boolean !Bool
+  | NumberObject !Number
+  | StringObject !StringObject
+  | NameObject !Name
+  | Array ![DirectObject]
+  | Dictionary !Dictionary
   | Null
-  | Reference IndirectObjCoordinates
+  | Reference !IndirectObjCoordinates
   deriving Show
 
 instance Output DirectObject where
@@ -204,23 +218,25 @@ instance Output DirectObject where
   output (NumberObject n) = output n
   output (StringObject s) = output s
   output (NameObject n) = output n
-  output (Array a) = Output.concat ["[", join " " a, "]"]
+  output (Array a) = mconcat ["[", join " " a, "]"]
   output (Dictionary d) = output d
   output (Null) = "null"
   output (Reference (IndirectObjCoordinates {objectId, versionNumber})) =
-    Output.string (printf "%d %d R" (getObjectId objectId) versionNumber)
+    Output.string (printf "%d %d R" (getId objectId) versionNumber)
 
-directObject :: Parser u DirectObject
-directObject =
-    Boolean <$> boolean
-  <|> Reference <$> reference {- defined before Number because Number is a prefix of it -}
+directObject :: MonadParser m => m DirectObject
+directObject = (peek >>= dispatch) <?> "direct object"
+  where
+    dispatch 't' = Boolean <$> boolean
+    dispatch 'f' = Boolean <$> boolean
+    dispatch '(' = StringObject <$> stringObject
+    dispatch '<' = StringObject <$> stringObject <|> Dictionary <$> dictionary
+    dispatch '/' = NameObject <$> name
+    dispatch '[' = Array <$> array
+    dispatch 'n' = nullObject *> return Null
+    dispatch _ =
+        Reference <$> reference {- defined before Number because Number is a prefix of it -}
       <|> NumberObject <$> number
-  <|> StringObject <$> stringObject
-  <|> NameObject <$> name
-  <|> Array <$> array
-  <|> Dictionary <$> dictionary
-  <|> const Null <$> nullObject
-  <?> "direct object"
 
 --
 -- Object
@@ -235,27 +251,34 @@ data Object =
 
 instance Output Object where
   output (Direct d) = output d
-  output (Stream {header, streamContent}) = Output.concat [
+  output (Stream {header, streamContent}) = mconcat [
         output header, newLine
       , Output.line "stream"
       , byteString streamContent
       , "endstream"
     ]
 
+object :: Int -> Id Object
+object = Id
+
 --
 -- Occurrence
 --
 data Occurrence = Comment String | Indirect IndirectObjCoordinates deriving Show
 
-outputOccurrence :: IndexedObjects -> Occurrence -> OBuilder
+outputOccurrence :: (Indexed Object) -> Occurrence -> OBuilder
 outputOccurrence _ (Comment c) = Output.line c
 outputOccurrence objects (Indirect (IndirectObjCoordinates {objectId, versionNumber})) =
-  saveOffset (Object objectId) >> Output.concat [
-        Output.line (printf "%d %d obj" (getObjectId objectId) versionNumber)
-      , output (objects ! objectId), newLine
+  saveOffset (ObjectId $ getId objectId) >> mconcat [
+        Output.line (printf "%d %d obj" (getId objectId) versionNumber)
+      , output (objects `Id.at` objectId), newLine
       , Output.line "endobj"
     ]
 
+outputBody :: ([Occurrence], (Indexed Object)) -> OBuilder
+outputBody (occurrences, objects) =
+  output (outputOccurrence objects <$> occurrences) <* saveOffset StartXRef
+
 -------------------------------------
 --          XREF TABLE
 -------------------------------------
@@ -267,15 +290,20 @@ data XRefEntry = InUse {
       offset :: Offset
     , generation :: Int
   } | Free {
-      nextFree :: ObjectId
+      nextFree :: (Id Object)
     , generation :: Int
   } deriving Show
 
 instance Output XRefEntry where
-  output (InUse {offset, generation}) =
-      Output.line (printf "%010d %05d n " (getOffset offset) generation)
-  output (Free {nextFree, generation}) =
-      Output.line (printf "%010d %05d f " (getObjectId nextFree) generation)
+  output xRefEntry = Output.string (build xRefEntry) `mappend` endXRefEntryLine
+    where
+      build (InUse {offset, generation}) =
+        printf "%010d %05d n" (getOffset offset) generation
+      build (Free {nextFree, generation}) =
+        printf "%010d %05d f" (getId nextFree) generation
+      endXRefEntryLine = OContext (asks padEOLToTwoBytes) >>= Output.line
+      padEOLToTwoBytes EOL.CRLF = ("" :: String)
+      padEOLToTwoBytes _ = " "
 
 entry :: Parser u XRefEntry
 entry = do
@@ -287,52 +315,51 @@ entry = do
       char 'n' *> return (InUse {offset = Offset big, generation})
     free :: Int -> Int -> Parser u XRefEntry
     free big generation =
-      char 'f' *> return (Free {nextFree = ObjectId big, generation})
+      char 'f' *> return (Free {nextFree = Id big, generation})
 
 --
 -- XRefSubSection
 --
 data XRefSubSection = XRefSubSection {
-      firstObjectId :: ObjectId
+      firstObjectId :: (Id Object)
     , entries :: [XRefEntry]
   } deriving Show
 
 instance Output XRefSubSection where
   output (XRefSubSection {firstObjectId, entries}) =
-      Output.line (printf "%d %d" (getObjectId firstObjectId) (length entries))
+      Output.line (printf "%d %d" (getId firstObjectId) (length entries))
     `mappend` output entries
 
 xRefSubSection :: Parser u XRefSubSection
 xRefSubSection = do
   (firstId, entriesNumber) <- (,) <$> integer <*> integer <?> "XRef subsection"
   entries <- count entriesNumber entry
-  return $ XRefSubSection {firstObjectId = ObjectId firstId, entries}
+  return $ XRefSubSection {firstObjectId = Id firstId, entries}
 
-type XRefSection = Map ObjectId XRefEntry
+type XRefSection = IdMap Object XRefEntry
 
 instance Output XRefSection where
   output = output . sections
     where
       sections tmp =
-        case Map.minViewWithKey tmp of
+        case Id.minViewWithKey tmp of
           Nothing -> []
-          Just ((objectId@(ObjectId value), firstEntry), rest) ->
+          Just ((objectId@(Id value), firstEntry), rest) ->
             let (subSection, sndRest) = section objectId [firstEntry] (value + 1) rest in
             subSection : sections sndRest
       section firstObjectId stack nextValue tmp =
-        let nextId = ObjectId nextValue in
-        case Map.lookup nextId tmp of
+        let nextId = (Id nextValue :: Id Object) in
+        case Id.lookup nextId tmp of
           Nothing -> (XRefSubSection {firstObjectId, entries = reverse stack}, tmp)
           Just nextEntry ->
-            section firstObjectId (nextEntry:stack) (nextValue + 1) (Map.delete nextId tmp)
-
+            section firstObjectId (nextEntry:stack) (nextValue + 1) (Id.delete nextId tmp)
 
 xRefSection :: Parser u XRefSection
-xRefSection = foldr addSubsection Map.empty <$>
+xRefSection = foldr addSubsection Id.empty <$>
   (line "xref" *> xRefSubSection `sepBy` many EOL.parser)
   where
     addSubsection (XRefSubSection {firstObjectId, entries}) =
-      Map.union . Map.fromList $ zip ([firstObjectId..]) entries
+      Id.union . Id.fromList $ zip ([firstObjectId..]) entries
 
 --
 -- Structure
@@ -353,45 +380,10 @@ structure =
   <$> xRefSection
   <*> (string "trailer" *> blank *> dictionary <* EOL.parser)
 
-updateXrefs :: XRefSection -> Map Resource Offset -> (XRefSection, Offset)
-updateXrefs xRef offsets = (mapWithKey updateEntry xRef, offsets ! StartXRef)
-  where
-    updateEntry objectId e@(InUse {}) = e {offset = offsets ! (Object objectId)}
-    updateEntry _ e = e
-
 --
 -- Flow
 --
 data Flow = Flow {
       occurrencesStack :: [Occurrence]
-    , tmpObjects :: IndexedObjects
+    , tmpObjects :: (Indexed Object)
   } deriving Show
-
---
--- Content
---
-data Content = Content {
-      occurrences :: [Occurrence]
-    , objects :: IndexedObjects
-    , docStructure :: Structure
-  } deriving Show
-
-outputBody :: ([Occurrence], IndexedObjects) -> OBuilder
-outputBody (occurrences, objects) =
-  output (outputOccurrence objects <$> occurrences) <* saveOffset StartXRef
-
-instance Output Content where
-  output (Content {occurrences, objects, docStructure}) =
-    fmap (updateXrefs xRef) <$> getOffsets (outputBody (occurrences, objects))
-    >>= \(body, (xref, startXRef)) -> Output.concat [
-          body
-        , Output.line "xref"
-        , output xref
-        , Output.line "trailer"
-        , output trailer, newLine
-        , Output.line "startxref"
-        , Output.line (printf "%d" (getOffset startXRef))
-        , byteString eofMarker
-      ]
-    where
-      Structure {xRef, trailer} = docStructure

src/PDF/Object/Navigation.hs

@@ -0,0 +1,180 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE DeriveFunctor #-}
+module PDF.Object.Navigation (
+      Nav(..)
+    , PPath(..)
+    , ROLayer
+    , RWLayer
+    , StreamContent(..)
+    , (./)
+    , (//)
+    , (>./)
+    , (>//)
+    , castObject
+    , catalog
+    , getDictionary
+    , getKey
+    , objectById
+    , save
+  ) where
+
+import Codec.Compression.Zlib (compress, decompress)
+import Control.Monad.Except (MonadError(..))
+import Control.Monad.Reader (MonadReader(..))
+import Control.Monad.State (MonadState)
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS (length)
+import qualified Data.ByteString.Lazy as Lazy (ByteString, fromStrict, toStrict)
+import Data.Id (Id)
+import qualified Data.Id as Id (at)
+import qualified Data.Map as Map (adjust, insert, lookup)
+import PDF.Box (Box(..), at, edit{-, runRO-})
+import PDF.Layer (Layer(..))
+import PDF.Object (
+      Dictionary, DirectObject(..), IndirectObjCoordinates(..)
+    , Name(..), Number(..), Object(..), Structure(..)
+  )
+import Prelude hiding (fail)
+import Text.Printf (printf)
+
+newtype PPath = PPath [Component]
+data DPath = DPath {
+      root :: Id Object
+    , offset :: [Component]
+  } deriving Show
+
+push :: Component -> DPath -> DPath
+push component dPath = dPath {offset = (offset dPath) ++ [component]}
+
+data Nav a = Nav {
+      dPath :: DPath
+    , value :: a
+  } deriving (Functor)
+
+instance Show a => Show (Nav a) where
+  show (Nav {dPath, value}) = "Nav {dPath = " ++ show dPath ++ ", value = " ++ show value ++ "}"
+
+type ROLayer m = (MonadReader Layer m, MonadError String m)
+type RWLayer m = (MonadState Layer m, MonadError String m)
+type Component = String
+
+getDictionary :: ROLayer m => Nav Object -> m (Nav Dictionary)
+getDictionary (Nav {dPath, value}) =
+  case value of
+    (Direct (Dictionary aDict)) -> return $ Nav {dPath, value = aDict}
+    (Direct (Reference ref)) -> objectById (objectId ref) >>= getDictionary
+    (Stream {header}) -> return $ Nav {dPath, value = header}
+    obj -> expected "dictionary : " obj
+
+expected :: (MonadError String m, Show a) => String -> a -> m b
+expected name = throwError . printf "Not a %s: %s" name . show
+
+getKey :: ROLayer m => String -> Nav Object -> m (Nav DirectObject)
+getKey key navObject = getDictionary navObject >>= f
+  where
+    errorMessage =
+      printf "Key %s not found in object %s" key (show navObject)
+    f (Nav {dPath, value}) =
+      case Map.lookup (Name key) value of
+        Nothing -> throwError errorMessage
+        Just dObj -> return $ Nav {dPath = push key dPath, value = dObj}
+
+objectById :: ROLayer m => (Id Object) -> m (Nav Object)
+objectById objectId = do
+  layer <- ask
+  return $ Nav {
+        dPath = DPath {root = objectId, offset = []}
+      , value = objects layer `Id.at` objectId
+    }
+
+castObject :: ROLayer m => Nav DirectObject -> m (Nav Object)
+castObject (Nav {value = !(Reference (IndirectObjCoordinates {objectId}))}) =
+  objectById objectId
+castObject (Nav {dPath, value}) = return $ Nav {dPath, value = Direct value}
+
+(./) :: ROLayer m => m (Nav Object) -> Component -> m (Nav Object)
+(./) navObject key = (navObject >>= getKey key >>= castObject)
+
+(//) :: ROLayer m => m (Nav Object) -> PPath -> m (Nav Object)
+(//) navObject (PPath []) = navObject
+(//) navObject (PPath (key:keys)) = navObject ./ key // (PPath keys)
+
+(>./) :: ROLayer m => Nav Object -> Component -> m (Nav Object)
+(>./) navObject = (return navObject ./)
+
+(>//) :: ROLayer m => Nav Object -> PPath -> m (Nav Object)
+(>//) navObject = (return navObject //)
+
+catalog :: ROLayer m => m (Nav Object)
+catalog = do
+  value <- Direct . Dictionary . trailer . docStructure <$> ask
+  return $ Nav {dPath = undefined, value}
+
+setAt :: [Component] -> DirectObject -> Dictionary -> Dictionary
+setAt [] _ dict = dict
+setAt [component] directObject dict =
+  Map.insert (Name component) directObject dict
+setAt (component:components) directObject dict =
+  Map.adjust setDirObj (Name component) dict
+  where
+    setDirObj (Dictionary subDict) =
+      Dictionary $ setAt components directObject subDict
+    setDirObj x = x
+
+save :: RWLayer m => Nav Object -> m ()
+save nav@(Nav {dPath, value = Direct dObj}) =
+  edit .at (root dPath) $ return . setObj
+  where
+    setObj obj@(Stream {header}) =
+      obj {header = setAt (offset dPath) dObj header}
+    setObj (Direct (Dictionary dict)) =
+      Direct . Dictionary $ setAt (offset dPath) dObj dict
+    setObj _ = value nav
+save (Nav {dPath = DPath {root, offset = []}, value}) = edit $ w root value
+save _ = throwError "Streams can't be properties of PDF objects"
+
+data StreamContent = Clear | Raw
+
+onLazy :: (Lazy.ByteString -> Lazy.ByteString) -> ByteString -> ByteString
+onLazy f = Lazy.toStrict . f . Lazy.fromStrict
+
+contains :: String -> DirectObject -> Bool
+contains needle !(NameObject (Name n)) = needle == n
+contains needle !(Array directObjects) = oneOf directObjects (contains needle)
+  where
+    oneOf [] _ = False
+    oneOf (x:xs) p = p x || oneOf xs p
+contains _ _ = False
+
+instance MonadError String m => Box m StreamContent (Nav Object) ByteString where
+  r sc = r sc . value
+  w sc newStreamContent nav = setValue <$> w sc newStreamContent (value nav)
+    where
+      setValue value = nav {value}
+
+instance MonadError String m => Box m StreamContent Object ByteString where
+  r Raw (Stream {streamContent}) = return streamContent
+  r Clear (Stream {header, streamContent}) = return $
+    case Map.lookup (Name "Filter") header of
+      Just directObject
+        | contains "FlateDecode" directObject -> onLazy decompress streamContent
+      _ -> streamContent
+  r _ obj = expected "stream" obj
+
+  w Raw streamContent obj@(Stream {}) = return $ obj {streamContent}
+  w Clear newStreamContent (Stream {header}) =
+    let streamContent = getStreamContent (Map.lookup (Name "Filter") header) in
+    return $ Stream {header = fixLength streamContent, streamContent}
+    where
+      getStreamContent (Just directObject)
+        | contains "FlateDecode" directObject = onLazy compress newStreamContent
+      getStreamContent _ = newStreamContent
+      fixLength sc =
+        let newLength = NumberObject . Number . fromIntegral $ BS.length sc in
+        Map.insert (Name "Length") newLength header
+  w _ _ obj = expected "stream" obj

src/PDF/Output.hs

@@ -5,14 +5,12 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 module PDF.Output (
       OBuilder
-    , ObjectId(..)
     , OContext(..)
     , Offset(..)
     , Output(..)
     , Resource(..)
     , byteString
     , char
-    , concat
     , getOffsets
     , join
     , line
@@ -32,12 +30,10 @@ import qualified Data.Map as Map (singleton)
 import Data.String (IsString(..))
 import Control.Monad.RWS (RWS, runRWS, ask, get, listen, modify, tell)
 import qualified PDF.EOL as EOL (Style(..))
-import Prelude hiding (concat)
 
-newtype ObjectId = ObjectId {getObjectId :: Int} deriving (Enum, Eq, Ord, Show)
 newtype Offset = Offset {getOffset :: Int} deriving (Show)
 
-data Resource = StartXRef | Object ObjectId deriving (Eq, Ord)
+data Resource = StartXRef | ObjectId Int deriving (Eq, Ord)
 
 newtype OContext a = OContext (RWS EOL.Style (Map Resource Offset) Offset a)
 type OBuilder = OContext Builder
@@ -59,16 +55,12 @@ saveOffset resource = OContext $
 lift :: (a -> Builder) -> a -> OBuilder
 lift f a = return (f a)
 
-getOffsets :: OBuilder -> OContext (OBuilder, Map Resource Offset)
-getOffsets (OContext builder) =
-  OContext (listen builder >>= \(a, w) -> return (return a, w))
+getOffsets :: OBuilder -> OContext (Builder, Map Resource Offset)
+getOffsets (OContext builder) = OContext $ listen builder
 
 append :: OBuilder -> OBuilder -> OBuilder
 append (OContext a) (OContext b) = OContext (mappend <$> a <*> b)
 
-concat :: [OBuilder] -> OBuilder
-concat = foldl mappend mempty
-
 #if MIN_VERSION_base(4,11,0)
 instance Semigroup OBuilder where
   (<>) = append
@@ -94,7 +86,7 @@ instance Output Bool where
   output True = string "true"
 
 instance Output a => Output [a] where
-  output = concat . fmap output
+  output = mconcat . fmap output
 
 join :: Output a => String -> [a] -> OBuilder
 join _ [] = mempty
@@ -116,7 +108,7 @@ char :: Char -> OBuilder
 char c = lift char8 c <* offset (+1)
 
 string :: String -> OBuilder
-string s = lift string8 s <* offset (+ toEnum (length s))
+string s = lift string8 s <* offset (+ length s)
 
 line :: String -> OBuilder
 line l = string l `mappend` newLine

src/PDF/Pages.hs

@@ -0,0 +1,181 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+module PDF.Pages (
+      Contents(..)
+    , FontCache
+    , Page(..)
+    , PageNumber(..)
+    , Pages(..)
+    , withFonts
+    , withResources
+  ) where
+
+import Control.Applicative (Alternative)
+import Control.Applicative ((<|>))
+import Control.Monad (foldM)
+import Control.Monad.Except (MonadError(..))
+import Control.Monad.Reader (ReaderT, runReaderT)
+import Control.Monad.State (StateT(..), evalStateT, execStateT, gets, modify)
+import Control.Monad.Trans (lift)
+import Data.ByteString (ByteString)
+import Data.ByteString.Lazy (toStrict)
+import Data.Id (Id(..), IdMap)
+import qualified Data.Id as Id (empty, insert, lookup)
+import Data.Map (Map)
+import qualified Data.Map as Map (empty, elems, fromList, insert, toList)
+import Data.Maybe (listToMaybe)
+import Data.OrderedMap (OrderedMap, build, mapi)
+import PDF.Box (Box(..), at, edit, runRO)
+import qualified PDF.CMap as CMap (parse)
+import PDF.Content (Content(..))
+import qualified PDF.Content as Content (parse)
+import PDF.Encoding (encoding)
+import PDF.EOL (Style(..))
+import PDF.Font (Font, FontSet)
+import PDF.Layer (Layer(..), LayerReader)
+import PDF.Object (
+      Dictionary, DirectObject(..), IndirectObjCoordinates(..)
+    , Name(..), Number(..), Object(..)
+  ,)
+import PDF.Object.Navigation (
+      Nav(..), PPath(..), ROLayer, RWLayer, StreamContent(..), (//), (>./)
+    , (>//), catalog, getDictionary, getKey, objectById, save
+  )
+import PDF.Output (render)
+import Text.Printf (printf)
+
+type CachedFonts = IdMap Object Font
+type FontCache m = StateT CachedFonts m
+data Page = Page {
+      byteContents :: OrderedMap (Id Object) ByteString
+    , resources :: Dictionary
+    , source :: (Id Object)
+  }
+
+loadByteContents :: ROLayer m => DirectObject -> m (OrderedMap (Id Object) ByteString)
+loadByteContents directObject = do
+  objs <- sequence . build objectById $ objectIds directObject
+  mapM (r Clear) objs
+  where
+    objectIds (Array l) = l >>= getReference
+    objectIds dirObj = getReference dirObj
+
+getFontDictionary :: (Alternative m, ROLayer m) => Nav Object -> m Dictionary
+getFontDictionary pageObj =
+    (pageObj >// PPath ["Resources", "Font"] >>= fmap value . getDictionary)
+  <|> return Map.empty
+
+cache :: ROLayer m => (Id Object -> FontCache m Font) -> Id Object -> FontCache m Font
+cache loader objectId =
+  gets (Id.lookup objectId) >>= maybe load return
+  where
+    load = do
+      value <- loader objectId
+      modify $ Id.insert objectId value
+      return value
+
+loadFont :: (Alternative m, ROLayer m) => Id Object -> FontCache m Font
+loadFont objectId = lift $ objectById objectId >>= tryMappings
+  where
+    tryMappings object =
+        (object >./ "ToUnicode" >>= r Clear >>= CMap.parse)
+      <|> (object >./ "Encoding" >>= loadEncoding . value)
+      <|> (throwError $ unknownFormat (show objectId) (show object))
+    unknownFormat = printf "Unknown font format for object #%s : %s"
+    loadEncoding :: MonadError String m => Object -> m Font
+    loadEncoding (Direct (NameObject (Name name))) = encoding name
+    loadEncoding object =
+      throwError $ printf "Encoding must be a name, not that : %s" $ show object
+
+loadResources :: (Alternative m, ROLayer m) => Dictionary -> FontCache m FontSet
+loadResources = foldM addFont Map.empty . Map.toList
+  where
+    addFont output (name, Reference (IndirectObjCoordinates {objectId})) =
+      flip (Map.insert name) output <$> cache loadFont objectId
+    addFont output _ = return output
+
+getReference :: DirectObject -> [Id Object]
+getReference (Reference (IndirectObjCoordinates {objectId})) = [objectId]
+getReference _ = []
+
+loadPage :: (Alternative m, ROLayer m) => Id Object -> m Page
+loadPage source = do
+  page <- objectById source
+  byteContents <- loadByteContents . value =<< getKey "Contents" page
+  resources <- getFontDictionary page
+  return $ Page {byteContents, resources, source}
+
+pagesList :: (Alternative m, ROLayer m) => m [Id Object]
+pagesList =
+    (catalog // PPath ["Root", "Pages", "Kids"] >>= getReferences . value)
+  <|> return []
+  where
+    getReferences (Direct (Array kids)) = return $ getReference =<< kids
+    getReferences _ = throwError "Not a pages array"
+
+editPagesList :: RWLayer m => ([DirectObject] -> [DirectObject]) -> m ()
+editPagesList f = do
+  pages <- runRO (catalog // PPath ["Root", "Pages"])
+  kids <- runRO (pages >./ "Kids")
+  count <- runRO (pages >./ "Count")
+  (newSize, newKids) <- editKids (value kids)
+  save $ kids {value = newKids}
+  save $ count {value = Direct $ NumberObject newSize}
+  where
+    editKids (Direct (Array pageRefs)) =
+      let result = f pageRefs in
+      return (Number . fromIntegral $ length result, Direct $ Array result)
+    editKids _ = throwError "Invalid format for Root.Pages.Kids (not an array)"
+
+updatePage :: RWLayer m => Page -> m ()
+updatePage (Page {byteContents}) = sequence_ $ mapi updateByteContent byteContents
+  where
+    updateByteContent source byteContent =
+      edit .at source .at Clear $ \_ -> return byteContent
+
+data Pages = Pages
+newtype PageNumber = P Int
+data Contents = Contents
+
+instance (Alternative m, MonadError String m) => Box m Pages Layer (Map Int Page) where
+  r Pages = runReaderT (numbered <$> pagesList >>= mapM loadPage)
+    where
+      numbered :: [Id Object] -> Map Int (Id Object)
+      numbered = Map.fromList . zip [1..]
+
+  w Pages pages = execStateT $ do
+    mapM_ updatePage pages
+    setPagesList $ Map.elems (source <$> pages)
+    where
+      setPagesList =
+        editPagesList . const . fmap (Reference . flip IndirectObjCoordinates 0)
+
+instance (Alternative m, MonadError String m) => Box m PageNumber Layer Page where
+  r (P p) layer
+    | p < 1 = throwError "Pages start at 1"
+    | otherwise = runReaderT (drop (p - 1) <$> pagesList >>= firstPage) layer
+      where
+        firstPage =
+          maybe (throwError "Page is out of bounds") loadPage . listToMaybe
+
+  w (P p) page = execStateT $ do
+    updatePage page
+    editPagesList $ setPage (Reference $ IndirectObjCoordinates (source page) 0)
+    where
+      setPage ref l = take (p-1) l ++ ref : drop p l
+
+instance Monad m => Box m Contents Page (OrderedMap (Id Object) Content) where
+  r Contents = return . fmap Content.parse . byteContents
+  w Contents contents page = return $ page {byteContents}
+    where
+      byteContents = toStrict . render LF <$> contents
+
+withFonts :: MonadError String m => (Layer -> FontCache (LayerReader m) a) -> Layer -> m a
+withFonts f layer = runReaderT (evalStateT (f layer) Id.empty) layer
+
+withResources :: (Alternative m, MonadError String m) => (Page -> ReaderT FontSet m b) -> Page -> FontCache (LayerReader m) b
+withResources f p =
+  loadResources (resources p) >>= lift . lift . runReaderT (f p)

src/PDF/Parser.hs

@@ -1,56 +1,78 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE UndecidableInstances #-}
 module PDF.Parser (
-      Parser
+      MonadParser(..)
+    , Parser
     , (<?>)
-    , block
-    , char
-    , choice
-    , count
-    , decNumber
-    , hexNumber
-    , many
     , octDigit
     , on
-    , oneOf
-    , option
     , runParser
-    , sepBy
-    , string
-    , takeAll
-    , takeAll1
+    , evalParser
   ) where
 
-import Control.Applicative ((<|>), empty)
+import Control.Applicative (Alternative, (<|>))
+import Control.Monad (MonadPlus)
+import Control.Monad.Fail (MonadFail(..))
 import Control.Monad.State (StateT(..), evalStateT)
-import Control.Monad.Trans (lift)
+import Control.Monad.Trans (MonadTrans(..))
 import qualified Data.Attoparsec.ByteString.Char8 as Atto (
-    Parser, char, parseOnly, satisfy, string, take, takeWhile, takeWhile1
+      Parser, char, decimal, double, endOfInput, parseOnly, peekChar', satisfy, string, take
+    , takeWhile, takeWhile1
   )
 import Data.ByteString (ByteString)
+import Data.ByteString.Char8.Util (B16Int(..))
 import Data.Char (toLower)
 import Data.Set (Set)
 import qualified Data.Set as Set (fromList, member, unions)
+import Prelude hiding (fail)
+
+type MonadDeps m = (MonadFail m, MonadPlus m)
+
+class MonadDeps m => MonadParser m where
+  block :: Int -> m ByteString
+  char :: Char -> m Char
+  decNumber :: m Int
+  floatNumber :: m Double
+  endOfInput :: m ()
+  hexNumber :: m B16Int
+  oneOf :: String -> m Char
+  peek :: m Char
+  string :: ByteString -> m ByteString
+  takeAll :: (Char -> Bool) -> m ByteString
+  takeAll1 :: (Char -> Bool) -> m ByteString
+
+instance MonadParser Atto.Parser where
+  block = Atto.take
+  char = Atto.char
+  endOfInput = Atto.endOfInput
+  decNumber = Atto.decimal
+  floatNumber = Atto.double
+  hexNumber = B16Int <$> Atto.takeWhile1 (`Set.member` hexDigits)
+  oneOf charSet = Atto.satisfy (`elem` charSet)
+  peek = Atto.peekChar'
+  string s = Atto.string s <?> show s
+  takeAll = Atto.takeWhile
+  takeAll1 = Atto.takeWhile1
+
+instance (MonadParser m, MonadTrans t, MonadDeps (t m)) => MonadParser (t m) where
+  block = lift . block
+  char = lift . char
+  endOfInput = lift $ endOfInput
+  decNumber = lift $ decNumber
+  floatNumber = lift $ floatNumber
+  hexNumber = lift $ hexNumber
+  oneOf = lift . oneOf
+  peek = lift $ peek
+  string = lift . string
+  takeAll = lift . takeAll
+  takeAll1 = lift . takeAll1
 
 type Parser s = StateT s Atto.Parser
 
-(<?>) :: Parser s a -> String -> Parser s a
+(<?>) :: (Alternative m, MonadFail m) => m a -> String -> m a
 (<?>) parser debugMessage = parser <|> fail debugMessage
 
-block :: Int -> Parser s ByteString
-block = lift . Atto.take
-
-char :: Char -> Parser s Char
-char = lift . Atto.char
-
-choice :: [Parser s a] -> Parser s a
-choice = foldr (<|>) empty
-
-count :: Int -> Parser s a -> Parser s [a]
-count 0 _ = return []
-count n p = (:) <$> p <*> count (n-1) p
-
-decNumber :: Parser s ByteString
-decNumber = lift $ Atto.takeWhile1 (`Set.member` digits)
-
 digits :: Set Char
 digits = Set.fromList ['0'..'9']
 
@@ -59,13 +81,7 @@ hexDigits = Set.unions [digits, Set.fromList af, Set.fromList $ toLower <$> af]
   where
     af = ['A'..'F']
 
-hexNumber :: Parser s ByteString
-hexNumber = lift $ Atto.takeWhile1 (`Set.member` hexDigits)
-
-many :: Parser s a -> Parser s [a]
-many parser = (:) <$> parser <*> many parser <|> return []
-
-octDigit :: Parser s Char
+octDigit :: MonadParser m => m Char
 octDigit = oneOf ['0'..'7']
 
 on :: Parser s a -> ByteString -> Parser s (Either String a)
@@ -74,25 +90,8 @@ on (StateT parserF) input = StateT $ \state ->
     Left errorMsg -> return (Left errorMsg, state)
     Right (result, newState) -> return (Right result, newState)
 
-oneOf :: String -> Parser s Char
-oneOf charSet = lift $ Atto.satisfy (`elem` charSet)
+runParser :: Parser s a -> s -> ByteString -> Either String (a, s)
+runParser parser initState = Atto.parseOnly (runStateT parser initState)
 
-option :: a -> Parser s a -> Parser s a
-option defaultValue p = p <|> pure defaultValue
-
-runParser :: Parser s a -> s -> ByteString -> Either String a
-runParser parser initState =
-  Atto.parseOnly (evalStateT parser initState)
-
-sepBy :: Parser s a -> Parser s b -> Parser s [a]
-sepBy parser separator =
-  option [] $ (:) <$> parser <*> many (separator *> parser)
-
-string :: ByteString -> Parser s ByteString
-string = lift . Atto.string
-
-takeAll :: (Char -> Bool) -> Parser s ByteString
-takeAll = lift . Atto.takeWhile
-
-takeAll1 :: (Char -> Bool) -> Parser s ByteString
-takeAll1 = lift . Atto.takeWhile1
+evalParser :: Parser s a -> s -> ByteString -> Either String a
+evalParser parser initState = Atto.parseOnly (evalStateT parser initState)

src/PDF/Update.hs

@@ -1,47 +0,0 @@
-{-# LANGUAGE NamedFieldPuns #-}
-module PDF.Update (
-    unify
-  ) where
-
-import Data.Map (member)
-import qualified Data.Map as Map (empty, union)
-import PDF.Object (
-      Content(..), IndexedObjects, IndirectObjCoordinates(..), Occurrence(..)
-    , Structure(..)
-  )
-
-emptyContent :: Content
-emptyContent = Content {
-      docStructure = Structure {xRef = Map.empty, trailer = Map.empty}
-    , objects = Map.empty
-    , occurrences = []
-  }
-
-unify :: [Content] -> Content
-unify = foldl complete emptyContent
-  where
-    complete tmpContent older =
-      let mergedObjects = Map.union (objects tmpContent) (objects older) in
-      Content {
-          docStructure =
-            unifyDocStructure (docStructure tmpContent) (docStructure older)
-        , objects = mergedObjects
-        , occurrences = 
-            unifyOccurrences mergedObjects (occurrences tmpContent) (occurrences older)
-      }
-
-unifyDocStructure :: Structure -> Structure -> Structure
-unifyDocStructure update original = Structure {
-      xRef = Map.union (xRef update) (xRef original)
-    , trailer = Map.union (trailer update) (trailer original)
-  }
-
-unifyOccurrences :: IndexedObjects -> [Occurrence] -> [Occurrence] -> [Occurrence]
-unifyOccurrences objects update = foldr addOlder update
-  where
-    addOlder occurrence@(Comment _) existing = occurrence : existing
-    addOlder occurrence@(Indirect indirect) existing =
-      if objectId indirect `member` objects
-      then occurrence : existing
-      else existing
-  

test/Main.hs

@@ -0,0 +1,9 @@
+{-# LANGUAGE OverloadedStrings #-}
+import Test.HUnit
+import Object (testNumber, testString)
+
+main :: IO ()
+main = runTestTT (TestList [
+      testNumber
+    , testString
+  ]) *> return ()

test/Object.hs

@@ -0,0 +1,50 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Object (
+      testNumber
+    , testString
+  ) where
+
+import Data.ByteString.Char8 (pack)
+import Data.ByteString.Char8.Util (B16Int(..))
+import PDF.Object (Number(..), StringObject(..), name, number, stringObject)
+import PDF.Parser (MonadParser, Parser, evalParser)
+import Test.HUnit
+
+check :: (Eq a, Show a) => Parser () a -> (a, String) -> Test
+check parser (aim, input) =
+  TestCase $ assertEqual message (Right aim) (parse input)
+  where
+    message = "parse: " ++ input
+    parse = evalParser parser () . pack
+
+testName :: Test
+testName = TestLabel "Name" . TestList $ check name <$> [
+  ]
+
+testNumber :: Test
+testNumber = TestLabel "Number" . TestList $ check number <$> [
+      (Number 123, "123")
+    , (Number 43445, "43445")
+    , (Number 17, "+17")
+    , (Number (-98), "-98")
+    , (Number 0, "0")
+    , (Number 34.5, "34.5")
+    , (Number (-3.62), "-3.62")
+    , (Number 123.6, "+123.6")
+    , (Number 4, "4.")
+    , (Number (-0.002), "-.002")
+    , (Number 0, "0.0")
+  ]
+
+testString :: Test
+testString = TestLabel "StringObject" . TestList $ check stringObject <$> [
+      (Literal "This is a string", "(This is a string)")
+    , (Literal "Strings may contain newlines\nand such .", "(Strings may contain newlines\nand such .)")
+    , (Literal "Strings may contain balanced parentheses ( ) and\nspecial characters ( * ! & } ^ % and so on ) .", "(Strings may contain balanced parentheses ( ) and\nspecial characters ( * ! & } ^ % and so on ) .)")
+    , (Literal "The following is an empty string .", "(The following is an empty string .)")
+    , (Literal "", "()")
+    , (Literal "It has zero ( 0 ) length .", "(It has zero ( 0 ) length .)")
+    , (Hexadecimal $ B16Int "4E6F762073686D6F7A206B6120706F702E", "<4E6F762073686D6F7A206B6120706F702E>")
+    , (Hexadecimal $ B16Int "901FA3", "<901FA3>")
+    , (Hexadecimal $ B16Int "901FA0", "<901FA>")
+  ]