Fix bugs preventing the objects from loading

src/PDF/Body.hs

@@ -4,11 +4,12 @@ module PDF.Body  where
 import Data.ByteString.Lazy.Char8 (ByteString)
 import qualified Data.ByteString.Lazy.Char8 as BS (drop, pack)
 import Data.Int (Int64)
+import Data.Map ((!))
 import qualified Data.Map as Map (insert, lookup)
 import PDF.Object (
       Content(..), DirectObject(..), IndirectObjCoordinates(..), Object(..)
     , Occurrence(..), Parser, XRefEntry(..), XRefSection, XRefSubSection(..)
-    , eol, eolCharset, dictionary, directObject, integer, line
+    , blank, eol, eolCharset, dictionary, directObject, integer, line
   )
 import Text.Parsec
 
@@ -55,17 +56,20 @@ getOffset objectId = do
       "obj " ++ show objectId ++ " is referenced but missing in XRef table"
     Just offset -> return offset
 
+on :: Monad m => ParsecT s u m a -> s -> ParsecT s u m a
+on parser input = do
+  originalInput <- getInput
+  setInput input >> parser <* setInput originalInput
+
 loadNumber :: Int -> SParser Float
 loadNumber objectId = do
   offset <- getOffset objectId
-  state <- getState
-  let objectStart = BS.drop offset (input state)
-  case runParser object state ("object@" ++ show offset) objectStart of
-    Left _ -> fail $ "Could not parse length object@" ++ show offset
-    Right number@(Direct (Number n)) ->
-      addObject objectId number >> return n
-    Right obj -> fail $
-      "Expected obj@" ++ show offset ++ " (" ++ show obj ++ ") to be a Number"
+  objectStart <- BS.drop offset . input <$> getState
+  indirectObjCoordinates `on` objectStart >> return ()
+  objectValue <- (!objectId) . objects . content <$> getState
+  case objectValue of
+    Direct (Number n) -> return n
+    obj -> fail $ "Expected obj@" ++ show offset ++ " (" ++ show obj ++ ") to be a Number"
 
 invalidValue :: Object -> String
 invalidValue v = "Invalid value " ++ show v
@@ -82,26 +86,28 @@ getSize (Just (Reference (IndirectObjCoordinates {objectId}))) = do
       invalidValue v ++ " for obj " ++ show objectId ++ "used as /Length"
 getSize (Just v) = fail $ invalidValue (Direct v) ++ " for /Length"
 
-object :: SParser Object
-object =
-    Direct <$> directObject
-  <|> do
-    header <- dictionary
-    size <- getSize (Map.lookup "Length" header)
-    streamContent <- BS.pack <$> stream (truncate size)
-    return $ Stream {header, streamContent}
+streamObject :: SParser Object
+streamObject = try $ do
+  header <- dictionary <* blank
+  size <- getSize (Map.lookup "Length" header)
+  streamContent <- BS.pack <$> stream (truncate size)
+  return $ Stream {header, streamContent}
   where
-    stream size = line "stream" *> count size anyChar <* eol <* line "endstream"
+    stream size = line "stream" *> count size anyChar <* blank <* line "endstream"
+
+object :: SParser Object
+object = streamObject <|> Direct <$> directObject
+
+indirectObjCoordinates :: SParser IndirectObjCoordinates
+indirectObjCoordinates = do
+  objectId <- integer
+  coordinates <- IndirectObjCoordinates objectId <$> integer
+  objectValue <- line "obj" *> object <* blank <* line "endobj"
+  addObject objectId objectValue
+  return coordinates
 
 occurrence :: SParser Occurrence
-occurrence = Comment <$> comment <|> indirectObj
-  where
-    indirectObj = do
-      objectId <- integer
-      coordinates <- IndirectObjCoordinates objectId <$> integer
-      objectValue <- line "obj" *> object <* eol <* line "endobj"
-      addObject objectId objectValue
-      return $ Indirect coordinates
+occurrence = Comment <$> comment <|> Indirect <$> indirectObjCoordinates
 
 populate :: ByteString -> Content -> Content
 populate input initialContent =

src/PDF/Object.hs

@@ -10,6 +10,7 @@ module PDF.Object (
     , XRefEntry(..)
     , XRefSection
     , XRefSubSection(..)
+    , blank
     , content
     , dictionary
     , directObject
@@ -108,11 +109,6 @@ blank = skipMany whiteSpace
 delimiterCharset :: String
 delimiterCharset = "()<>[]{}/%"
 
-{-
-delimiter :: Parser u Char
-delimiter = oneOf delimiterCharset
--}
-
 regular :: Parser u Char
 regular = noneOf $ eolCharset ++ whiteSpaceCharset ++ delimiterCharset
 
@@ -145,7 +141,7 @@ stringObj =
     Literal <$> (char '(' *> (concat <$> many literalStringBlock) <* char ')')
   <|> Hexadecimal <$> (char '<' *> many hexDigit <* char '>')
   where
-    literalStringBlock = many (noneOf "\\(") <|> matchingParenthesis <|> escapedChar
+    literalStringBlock = many1 (noneOf "\\()") <|> matchingParenthesis <|> escapedChar
     matchingParenthesis =
       (++) <$> ((:) <$> char '(' <*> literalStringBlock) <*> string ")"
     escapedChar = (:) <$> char '\\' <*> ((:[]) <$> oneOf "nrtbf()\\" <|> octalCode)