WIP: still trying to figure things out, moved to a separate submodule for Navigation, proper naming is hell
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@ -21,6 +21,7 @@ library
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, PDF.Content
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, PDF.EOL
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, PDF.Object
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, PDF.Object.Navigation
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, PDF.Output
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, PDF.Parser
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, PDF.Pages
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@ -12,6 +12,7 @@ module PDF.CMap (
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) where
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import Control.Applicative ((<|>), many)
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import Control.Monad.Fail (MonadFail(..))
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import Control.Monad.State (modify)
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import Data.Attoparsec.ByteString.Char8 (count)
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import Data.ByteString (ByteString)
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@ -32,6 +33,7 @@ import PDF.Object (
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, blank, directObject, integer, line, stringObject
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)
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import PDF.Parser (MonadParser, Parser, runParser, takeAll)
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import Prelude hiding (fail)
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type CMappers = Map Name CMap
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type Mapping = Map ByteString Text
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@ -70,8 +72,8 @@ matches :: ByteString -> CRange -> Bool
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matches code (CRange {fromSequence, toSequence}) =
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fromSequence <= code && code <= toSequence
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cMap :: ByteString -> Either String Font
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cMap = fmap (toFont . snd) <$> runParser
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cMap :: MonadFail m => ByteString -> m Font
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cMap = either fail (return . toFont . snd) . runParser
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(many (codeRanges <|> cMapRange <|> cMapChar <|> ignoredLine))
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emptyCMap
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where
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@ -1,8 +1,6 @@
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE NamedFieldPuns #-}
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{-# LANGUAGE FlexibleInstances #-}
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{-# LANGUAGE ConstraintKinds #-}
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{-# LANGUAGE FlexibleContexts #-}
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module PDF.Object (
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Content(..)
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, Dictionary
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@ -19,7 +17,6 @@ module PDF.Object (
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, Structure(..)
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, XRefEntry(..)
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, XRefSection
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, (//)
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, array
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, blank
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, dictionary
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@ -37,8 +34,6 @@ module PDF.Object (
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) where
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import Control.Applicative ((<|>), many)
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import Control.Monad.Reader (MonadReader(..))
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import Control.Monad.Fail (MonadFail(..))
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import Data.Attoparsec.ByteString.Char8 (choice, count, option, sepBy)
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import Data.ByteString (ByteString)
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import qualified Data.ByteString as BS (concat)
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@ -56,7 +51,6 @@ import PDF.Output (
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, saveOffset
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)
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import PDF.Parser (MonadParser(..), Parser, (<?>), octDigit, oneOf)
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import Prelude hiding (fail)
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import Text.Printf (printf)
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line :: MonadParser m => String -> m ()
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@ -168,10 +162,10 @@ array =
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type Dictionary = Map Name DirectObject
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instance Output Dictionary where
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output dict =
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output aDictionary =
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"<<" `mappend` keyValues `mappend` ">>"
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where
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keyValues = join " " $ outputKeyVal <$> Map.toList dict
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keyValues = join " " $ outputKeyVal <$> Map.toList aDictionary
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outputKeyVal :: (Name, DirectObject) -> OBuilder
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outputKeyVal (key, val) = Output.concat [output key, " ", output val]
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@ -410,36 +404,3 @@ instance Output Content where
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]
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where
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Structure {xRef, trailer} = docStructure
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type PDFContent m = (MonadReader Content m, MonadFail m)
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--
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-- Navigation
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--
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key :: MonadFail m => String -> Dictionary -> m DirectObject
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key keyName dictionary =
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maybe (fail errorMessage) return (Map.lookup (Name keyName) dictionary)
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where
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errorMessage =
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printf "Key %s not found in dictionary %s" keyName (show dictionary)
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dict :: PDFContent m => Object -> m Dictionary
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dict (Direct (Dictionary aDict)) = return aDict
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dict obj = fail $ "Not a dictionary : " ++ show obj
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getObject :: PDFContent m => ObjectId -> m Object
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getObject objectId = do
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content <- ask
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return (objects content ! objectId)
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getResource :: PDFContent m => DirectObject -> m Dictionary
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getResource (Dictionary aDict) = return aDict
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getResource (Reference (IndirectObjCoordinates {objectId})) =
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getObject objectId >>= dict
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getResource directObject =
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fail $ "Not a resource (dictionary or reference) : " ++ show directObject
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(//) :: PDFContent m => Dictionary -> [String] -> m DirectObject
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(//) aDict [] = return $ Dictionary aDict
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(//) aDict [field] = key field aDict
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(//) aDict (field:fields) = key field aDict >>= getResource >>= (// fields)
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@ -0,0 +1,70 @@
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{-# LANGUAGE NamedFieldPuns #-}
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{-# LANGUAGE ConstraintKinds #-}
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{-# LANGUAGE FlexibleContexts #-}
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module PDF.Object.Navigation (
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(//)
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, getDictionary
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, getField
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, getObject
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, openStream
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, origin
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) where
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import Codec.Compression.Zlib (decompress)
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import Control.Monad.Reader (MonadReader(..))
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import Control.Monad.Fail (MonadFail(..))
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import Data.ByteString (ByteString)
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import qualified Data.ByteString.Lazy as Lazy (fromStrict, toStrict)
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import Data.Map ((!))
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import qualified Data.Map as Map (lookup)
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import PDF.Object (
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Content(..), Dictionary, DirectObject(..), IndirectObjCoordinates(..)
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, Name(..), Object(..), Structure(..)
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)
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import PDF.Output (ObjectId)
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import Prelude hiding (fail)
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import Text.Printf (printf)
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type PDFContent m = (MonadReader Content m, MonadFail m)
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expected :: (PDFContent m, Show a) => String -> a -> m b
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expected name = fail . printf "Not a %s: %s" name . show
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getField :: MonadFail m => String -> Dictionary -> m DirectObject
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getField key aDictionary =
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maybe (fail errorMessage) return (Map.lookup (Name key) aDictionary)
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where
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errorMessage =
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printf "Key %s not found in dictionary %s" key (show aDictionary)
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castDictionary :: PDFContent m => Object -> m Dictionary
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castDictionary (Direct (Dictionary aDict)) = return aDict
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castDictionary obj = expected "dictionary : " obj
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getObject :: PDFContent m => ObjectId -> m Object
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getObject objectId = do
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content <- ask
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return (objects content ! objectId)
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getDictionary :: PDFContent m => DirectObject -> m Dictionary
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getDictionary (Dictionary aDictionary) = return aDictionary
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getDictionary (Reference (IndirectObjCoordinates {objectId})) =
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getObject objectId >>= castDictionary
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getDictionary aDirectObject =
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expected "resource (dictionary or reference)" aDirectObject
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(//) :: PDFContent m => Dictionary -> [String] -> m DirectObject
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(//) aDict [] = return $ Dictionary aDict
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(//) aDict [key] = getField key aDict
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(//) aDict (key:keys) = getField key aDict >>= getDictionary >>= (// keys)
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origin :: PDFContent m => m Dictionary
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origin = trailer . docStructure <$> ask
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openStream :: PDFContent m => Object -> m ByteString
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openStream (Stream {header, streamContent}) = return $
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case Map.lookup (Name "Filter") header of
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Just (NameObject (Name "FlateDecode")) ->
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Lazy.toStrict . decompress . Lazy.fromStrict $ streamContent
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_ -> streamContent
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openStream obj = expected "stream" obj
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@ -5,13 +5,13 @@ module PDF.Pages (
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, getAll
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) where
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import Codec.Compression.Zlib (decompress)
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import Control.Applicative ((<|>))
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import Control.Monad (foldM)
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import Control.Monad.Except (Except, runExcept)
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import Control.Monad.Fail (MonadFail(..))
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import Control.Monad.RWS (RWST(..), ask, evalRWST, lift, modify)
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import qualified Control.Monad.RWS as RWS (get)
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import Data.ByteString (ByteString)
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import qualified Data.ByteString.Lazy as Lazy (fromStrict, toStrict)
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import Data.Map (Map, (!))
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import qualified Data.Map as Map (empty, fromList, insert, lookup, toList)
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import Data.Text (Text)
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@ -24,11 +24,13 @@ import PDF.Object (
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Content(..), Dictionary, DirectObject(..), IndirectObjCoordinates(..)
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, Object(..), Name(..), Structure(..)
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,)
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import PDF.Object.Navigation ((//), getDictionary, origin, stream)
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import PDF.Output (ObjectId(..))
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import Prelude hiding (fail)
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import Text.Printf (printf)
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type CachedFonts = Map ObjectId Font
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type T = RWST Content () CachedFonts (Either String)
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type T = RWST Content () CachedFonts (Except String)
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data Page = Page {
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contents :: [Text]
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, source :: ObjectId
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@ -42,17 +44,6 @@ infixl 1 //=
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(//=) :: Either String a -> (a -> T b) -> T b
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x //= f = lift x >>= f
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expected :: Show a => String -> a -> Either String b
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expected name = Left . printf "Not a %s: %s" name . show
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stream :: Object -> Either String ByteString
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stream (Stream {header, streamContent}) = Right $
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case Map.lookup (Name "Filter") header of
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Just (NameObject (Name "FlateDecode")) ->
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Lazy.toStrict . decompress . Lazy.fromStrict $ streamContent
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_ -> streamContent
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stream obj = expected "stream" obj
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getResource :: DirectObject -> T Dictionary
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getResource (Dictionary dictionary) = return dictionary
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getResource (Reference (IndirectObjCoordinates {objectId})) =
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@ -81,10 +72,10 @@ loadFont objectId = getObject objectId \\= dict >>= tryMappings
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tryMappings dictionary =
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loadCMap dictionary
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<|> lift (key "Encoding" dictionary >>= loadEncoding)
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<|> lift (Left $ unknownFormat (show objectId) (show dictionary))
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<|> (fail $ unknownFormat (show objectId) (show dictionary))
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unknownFormat = printf "Unknown font format for object #%s : %s"
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loadCMap dictionary =
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key "ToUnicode" dictionary //= follow \\= stream \\= cMap
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getField "ToUnicode" dictionary >>= follow \\= stream >>= cMap
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loadEncoding (NameObject (Name name)) = encoding name
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loadEncoding directObject =
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Left . printf "Encoding must be a name, not that : %s" $ show directObject
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@ -129,8 +120,7 @@ dictObject keyName dictionary = key keyName dictionary //= follow \\= dict
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pagesList :: T [ObjectId]
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pagesList = do
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root <- dictObject "Root" . trailer . docStructure =<< ask
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pages <- dictObject "Pages" root
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pages <- origin >>= (// ["Root", "Pages"]) >>= getDictionary
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case Map.lookup (Name "Kids") pages of
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Just (Array kids) -> return $ getReferences kids
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_ -> return []
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@ -158,7 +148,7 @@ loadPage source =
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(\contents -> Page {contents, source}) <$> (extractText =<< getObject source)
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getAll :: Content -> Either String (Map Int Page)
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getAll content = fst <$> evalRWST getPages content Map.empty
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getAll content = runExcept $ fst <$> evalRWST getPages content Map.empty
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where
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numbered = Map.fromList . zip [1..]
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getPages = numbered <$> (mapM loadPage =<< pagesList)
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@ -166,8 +156,8 @@ getAll content = fst <$> evalRWST getPages content Map.empty
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get :: Content -> Int -> Either String Page
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get content pageNumber
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| pageNumber < 1 = Left "Pages start at 1"
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| otherwise = fst <$> evalRWST getPage content Map.empty
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| otherwise = runExcept $ fst <$> evalRWST getPage content Map.empty
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where
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firstPage [] = lift $ Left "Page is out of bounds"
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firstPage [] = fail "Page is out of bounds"
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firstPage (p:_) = loadPage p
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getPage = drop (pageNumber - 1) <$> pagesList >>= firstPage
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