320 lines
12 KiB
Haskell
320 lines
12 KiB
Haskell
{-# LANGUAGE NamedFieldPuns #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE ConstraintKinds #-}
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{-# LANGUAGE FlexibleContexts #-}
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module PDF.Text {-(
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pageContents
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)-} where
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import Control.Applicative ((<|>))
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import Control.Monad (foldM)
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import Control.Monad.Fail (MonadFail)
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import Control.Monad.Reader (ReaderT, runReaderT, asks)
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import Control.Monad.State (MonadState, evalStateT, get, modify, put)
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import Data.Attoparsec.ByteString.Char8 (choice, sepBy)
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import Data.ByteString (ByteString)
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import Data.ByteString.Char8 (pack, unpack)
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import Data.Char (toLower)
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import Data.Map ((!), (!?), Map)
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import qualified Data.Map as Map (fromList)
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import Data.Text (Text)
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import PDF.Font (Font, FontSet, emptyFont)
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import PDF.Object (
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DirectObject(..), StringObject(..)
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, array, blank, name, regular, stringObject, toByteString
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)
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import PDF.Parser (MonadParser(..), (<?>), Parser, evalParser)
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data StateOperator =
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C_m | W_ | J | J_ | M | D_ | R_i | I_ | G_s -- general graphic state
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deriving (Bounded, Enum, Show)
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data PathOperator =
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M_ | L_ | C_ | V_ | Y_ | H_ | R_e -- path construction
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| S | S_ | F_ | F | Fstar | B | Bstar | B_ | B_star | N_ -- path painting
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| W | Wstar -- clipping path
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deriving (Bounded, Enum, Show)
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data ColorOperator =
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CS | C_s | SC | SCN | S_c | S_cn | G | G_ | RG | R_g | K | K_
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deriving (Bounded, Enum, Show)
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data TextOperator =
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Td | TD | Tm | Tstar -- text positioning
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| TJ | Tj | Quote | DQuote -- text showing
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| Tc | Tw | Tz | TL | Tf | Tr | Ts -- text state
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deriving (Bounded, Enum, Show)
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data Argument = Raw ByteString | Typed DirectObject deriving Show
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type Call a = (a, [Argument])
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type Operator a = (Bounded a, Enum a, Show a)
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code :: Operator a => a -> ByteString
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code = pack . expand . show
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where
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expand "" = ""
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expand (c:'_':s) = toLower c : expand s
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expand ('s':'t':'a':'r':s) = '*' : expand s
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expand ('Q':'u':'o':'t':'e':s) = '\'' : expand s
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expand ('D':'Q':'u':'o':'t':'e':s) = '"' : expand s
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expand (c:s) = c : expand s
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{-
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instance Show StateOperator where
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show Cm = "cm"
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show W_ = "w"
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show J = "J"
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show J_ = "j"
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show M = "M"
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show D = "d"
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show Ri = "ri"
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show I = "i"
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show Gs = "gs"
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instance Show PathOperator where
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show M_ = "m"
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show L_ = "l"
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show C_ = "c"
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show V_ = "v"
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show Y_ = "y"
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show H_
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("m", (M_, \l -> case l of [Raw _, Raw _] -> True ; _ -> False))
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, ("l", (L_, \l -> case l of [Raw _, Raw _] -> True ; _ -> False))
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, ("c", (L_, \l -> case l of [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False))
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, ("v", (L_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False))
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, ("y", (L_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False))
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, ("h", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("re", (L_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False))
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, ("S", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("s", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("f", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("F", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("F*", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("B", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("B*", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("b", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("b*", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("n", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("W", (L_, \l -> case l of [] -> True ; _ -> False))
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, ("W*", (L_, \l -> case l of [] -> True ; _ -> False))
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instance Show ColorOperator where
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instance Show TextOperator where
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show Td = "Td"
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show TD = "TD"
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show Tm = "Tm"
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show Tstar = "T*"
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show TJ = "TJ"
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show Tj = "Tj"
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show Quote = "'"
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show DQuote = "\""
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show Tc = "Tc"
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show Tw = "Tw"
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show Tz = "Tz"
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show TL = "TL"
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show Tf = "Tf"
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show Tr = "Tr"
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show Ts = "Ts"
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-}
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stateOperator :: OperatorTable StateOperator
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stateOperator = Map.fromList $ (\(op, checker) -> (code op, (op, checker))) <$> [
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(C_m, \l -> case l of [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (W_, \l -> case l of [Raw _] -> True ; _ -> False)
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, (J, \l -> case l of [Raw _] -> True ; _ -> False)
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, (J_, \l -> case l of [Raw _] -> True ; _ -> False)
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, (M, \l -> case l of [Raw _] -> True ; _ -> False)
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, (D_, \l -> case l of [Raw _, Raw _] -> True ; _ -> False)
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, (R_i, \l -> case l of [Raw _] -> True ; _ -> False)
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, (I_, \l -> case l of [Raw _] -> True ; _ -> False)
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, (G_s, \l -> case l of [Typed (NameObject _)] -> True ; _ -> False)
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]
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pathOperator :: OperatorTable PathOperator
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pathOperator = Map.fromList $ (\(op, checker) -> (code op, (op, checker))) <$> [
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(M_, \l -> case l of [Raw _, Raw _] -> True ; _ -> False)
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, (L_, \l -> case l of [Raw _, Raw _] -> True ; _ -> False)
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, (C_, \l -> case l of [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (V_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (Y_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (H_, \l -> case l of [] -> True ; _ -> False)
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, (R_e, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (S, \l -> case l of [] -> True ; _ -> False)
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, (S_, \l -> case l of [] -> True ; _ -> False)
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, (F_, \l -> case l of [] -> True ; _ -> False)
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, (F, \l -> case l of [] -> True ; _ -> False)
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, (Fstar, \l -> case l of [] -> True ; _ -> False)
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, (B, \l -> case l of [] -> True ; _ -> False)
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, (Bstar, \l -> case l of [] -> True ; _ -> False)
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, (B_, \l -> case l of [] -> True ; _ -> False)
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, (B_star, \l -> case l of [] -> True ; _ -> False)
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, (N_, \l -> case l of [] -> True ; _ -> False)
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, (W, \l -> case l of [] -> True ; _ -> False)
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, (Wstar, \l -> case l of [] -> True ; _ -> False)
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]
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colorOperator :: OperatorTable ColorOperator
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colorOperator = Map.fromList $ (\(op, checker) -> (code op, (op, checker))) <$> [
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(CS, \l -> case l of [Typed (NameObject _)] -> True ; _ -> False)
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, (C_s, \l -> case l of [Typed (NameObject _)] -> True ; _ -> False)
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, (SC, \_ -> True)
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, (SCN, \_ -> True)
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, (S_c, \_ -> True)
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, (S_cn, \_ -> True)
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, (G, \l -> case l of [Raw _] -> True ; _ -> False)
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, (G_, \l -> case l of [Raw _] -> True ; _ -> False)
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, (RG, \l -> case l of [Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (R_g, \l -> case l of [Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (K, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (K_, \l -> case l of [Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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]
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{-
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stateOperator (Cm, [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _]) = True
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stateOperator (W, [Raw _]) = True
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stateOperator (J, [Raw _]) = True
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stateOperator (J_, [Raw _]) = True
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stateOperator (M, [Raw _]) = True
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stateOperator (D, [Raw _, Raw _]) = True
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stateOperator (Ri, [Raw _]) = True
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stateOperator (I, [Raw _]) = True
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stateOperator (Gs, [Typed (NameObject _)]) = True
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stateOperator _ = False
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-}
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textOperator :: OperatorTable TextOperator
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textOperator = Map.fromList $ (\(op, checker) -> (code op, (op, checker))) <$> [
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(Td, \l -> case l of [Raw _, Raw _] -> True ; _ -> False)
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, (TD, \l -> case l of [Raw _, Raw _] -> True ; _ -> False)
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, (Tm, \l -> case l of [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _] -> True ; _ -> False)
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, (Tstar, \l -> case l of [] -> True ; _ -> False)
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, (TJ, \l -> case l of [Typed (Array _)] -> True ; _ -> False)
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, (Tj, \l -> case l of [Typed (StringObject _)] -> True ; _ -> False)
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, (Quote, \l -> case l of [Typed (StringObject _)] -> True ; _ -> False)
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, (DQuote, \l -> case l of [Typed (StringObject _)] -> True ; _ -> False)
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, (Tc, \l -> case l of [Raw _] -> True ; _ -> False)
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, (Tw, \l -> case l of [Raw _] -> True ; _ -> False)
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, (Tz, \l -> case l of [Raw _] -> True ; _ -> False)
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, (TL, \l -> case l of [Raw _] -> True ; _ -> False)
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, (Tf, \l -> case l of [Typed (NameObject _), Raw _] -> True ; _ -> False)
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, (Tr, \l -> case l of [Raw _] -> True ; _ -> False)
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, (Ts, \l -> case l of [Raw _] -> True ; _ -> False)
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]
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{-
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textOperator (Td, [Raw _, Raw _]) = True
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textOperator (TD, [Raw _, Raw _]) = True
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textOperator (Tm, [Raw _, Raw _, Raw _, Raw _, Raw _, Raw _]) = True
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textOperator (Tstar, []) = True
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textOperator (TJ, [Typed (Array _)]) = True
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textOperator (Tj, [Typed (StringObject _)]) = True
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textOperator (Quote, [Typed (StringObject _)]) = True
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textOperator (DQuote, [Typed (StringObject _)]) = True
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textOperator (Tc, [Raw _]) = True
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textOperator (Tw, [Raw _]) = True
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textOperator (Tz, [Raw _]) = True
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textOperator (TL, [Raw _]) = True
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textOperator (Tf, [Typed (NameObject _), Raw _]) = True
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textOperator (Tr, [Raw _]) = True
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textOperator (Ts, [Raw _]) = True
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textOperator _ = False
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-}
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type ArgumentStackParser m = (MonadState [Argument] m, MonadParser m)
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--type Operator a = (Bounded a, Enum a, Show a)
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type OperatorTable a = Map ByteString (TypeChecker a)
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type TypeChecker a = (a, [Argument] -> Bool)
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parseShowable :: (Show a, MonadParser m) => a -> m a
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parseShowable textOp = string (pack $ show textOp) *> return textOp
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callChunk :: MonadParser m => OperatorTable a -> m (Either (TypeChecker a) Argument)
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callChunk table =
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(Right <$> choice [stringArg, nameArg, arrayArg])
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<|> operatorOrRawArg
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<?> "call chunk"
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where
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operatorOrRawArg = do
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chunk <- takeAll1 regular <* blank
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case table !? chunk of
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Nothing -> return . Right $ Raw chunk
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Just typeChecker -> return $ Left typeChecker
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stackParser :: (ArgumentStackParser m, Operator a) => OperatorTable a -> m (Call a)
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stackParser table = either popCall push =<< (callChunk table)
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where
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push arg = modify (arg:) >> stackParser table
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popCall (operator, predicate) = do
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arguments <- reverse <$> get
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let call = (operator, arguments)
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if predicate arguments then return call else fail (unpack $ code operator)
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a :: (Operator a, MonadParser m) => OperatorTable a -> m (Call a)
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a table = evalStateT (stackParser table) []
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argument :: MonadParser m => m Argument
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argument = Raw <$> takeAll1 regular <* blank
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arrayArg :: MonadParser m => m Argument
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arrayArg = Typed . Array <$> array <* blank
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nameArg :: MonadParser m => m Argument
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nameArg = Typed . NameObject <$> name <* blank
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stringArg :: MonadParser m => m Argument
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stringArg = Typed . StringObject <$> stringObject <* blank
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type ParserWithFont = ReaderT FontSet (Parser Font)
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pageContents :: FontSet -> ByteString -> Either String [Text]
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pageContents fontSet input =
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evalParser (runReaderT (page) fontSet) emptyFont input
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several :: MonadParser m => m [a] -> m [a]
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several p = concat <$> (p `sepBy` blank)
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page :: ParserWithFont [Text]
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page = several (graphicState <|> text) <* blank <* endOfInput <?> "Text page contents"
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graphicState :: ParserWithFont [Text]
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graphicState =
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string "q" *> blank *> insideQ <* blank <* string "Q" <?> "Graphic state"
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where
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insideQ = several (command <|> graphicState <|> text)
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ignore x = a x *> return []
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command =
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ignore stateOperator <|> ignore pathOperator <|> ignore colorOperator
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text :: ParserWithFont [Text]
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text =
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string "BT" *> blank *> commands <* blank <* string "ET" <?> "Text operators"
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where
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commands = several (a textOperator >>= runOperator)
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runOperator :: Call TextOperator -> ParserWithFont [Text]
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runOperator (Tf, [Typed (NameObject fontName), _]) =
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asks (! fontName) >>= put >> return []
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runOperator (Tstar, []) = return ["\n"]
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runOperator (TJ, [Typed (Array arrayObject)]) =
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replicate 1 <$> foldM appendText "" arrayObject
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where
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appendText bs (StringObject outputString) =
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mappend bs <$> decodeString outputString
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appendText bs _ = return bs
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runOperator (Tj, [Typed (StringObject outputString)]) =
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replicate 1 <$> decodeString outputString
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runOperator (Quote, [Typed (StringObject outputString)]) =
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(\bs -> ["\n", bs]) <$> decodeString outputString
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runOperator (DQuote, [Typed (StringObject outputString)]) =
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(\bs -> ["\n", bs]) <$> decodeString outputString
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runOperator _ = return []
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decodeString :: (MonadFail m, MonadState Font m) => StringObject -> m Text
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decodeString input = do
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font <- get
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either fail return . font $ toByteString input
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