Optimized big-num serialization.

1 files changed, 8 insertions, 6 deletions

diff --git a/Data/OpenPGP.hs b/Data/OpenPGP.hs
index 0e1150f..74223b2 100644
--- a/Data/OpenPGP.hs
+++ b/Data/OpenPGP.hs
@@ -69,6 +69,7 @@ import Numeric
 import Control.Monad
 import Control.Arrow
 import Control.Applicative
+import Data.Function
 import Data.Monoid
 import Data.Bits
 import Data.Word
@@ -287,7 +288,7 @@ instance BINARY_CLASS Packet where
         get = do
                 tag <- get
                 let (t, l) =
-                        if (tag .&. 64) /= 0 then
+                        if testBit tag 6 then
                                 (tag .&. 63, parse_new_length)
                         else
                                 ((tag `shiftR` 2) .&. 15, (,) <$> parse_old_length tag <*> pure False)
@@ -1004,7 +1005,9 @@ instance BINARY_CLASS MPI where
         put (MPI i)
                 | i >= 0 = do
                         put (bitl :: Word16)
-                        putSomeByteString bytes
+                        flip fix (B.length bytes - 1) $ \loop j -> do
+                                put (B.index bytes j)
+                                when (j /= 0) $ loop (j - 1)
                 | otherwise = fail $ "MPI is less than 0: " ++ show i
                 where
                 (bytes, bitl)
@@ -1013,16 +1016,15 @@ instance BINARY_CLASS MPI where
                                 (bytes', (fromIntegral (B.length bytes') - 1) * 8 + sigBit)
 
                 sigBit = fst $ until ((==0) . snd)
-                        (first (+1) . second (`shiftR` 1)) (0,B.index bytes 0)
-                bytes' = B.reverse $ B.unfoldr (\x ->
+                        (first (+1) . second (`shiftR` 1)) (0,B.last bytes)
+                bytes' = B.unfoldr (\x ->
                                 if x == 0 then Nothing else
                                         Just (fromIntegral x, x `shiftR` 8)
                         ) i
         get = do
                 length <- fmap fromIntegral (get :: Get Word16)
                 bytes <- getSomeByteString =<< assertProp (>0) ((length + 7) `div` 8)
-                return (MPI (B.foldl (\a b ->
-                        a `shiftL` 8 .|. fromIntegral b) 0 bytes))
+                return $ MPI $ B.foldl (\a b -> (a `shiftL` 8) + fromIntegral b) 0 bytes
 
 listUntilEnd :: (BINARY_CLASS a) => Get [a]
 listUntilEnd = do