What happens if you use `getRemainingLazyByteString' in your error branch instead of `getLazyByteString'?
On Tue, Jun 2, 2009 at 4:31 PM, David Leimbach <[email protected]> wrote: > > > On Tue, Jun 2, 2009 at 1:28 PM, John Van Enk <[email protected]> wrote: >> >> I think Thomas' point was that some other branch in `getSpecific' is >> running. Is there a chance we can see the rest of `getSpecific'? > > Sure: (In the meantime, I'll try the suggested code from before) > get = do s <- getWord32le > mtype <- getWord8 > getSpecific s mtype > where > getSpecific s mt > | mt == mtRversion = do t <- getWord16le > ms <- getWord32le > ss <- getWord16le > v <- > getRemainingLazyByteString > return $ MessageClient $ > Rversion {size=s, > > mtype=mt, > > tag=t, > > msize=ms, > > ssize=ss, > > version=v} > | mt == mtRerror = do t <- getWord16le > ss <- getWord16le > e <- getLazyByteString $ > fromIntegral ss > return $ MessageClient $ Rerror > {size=s, > > mtype=mt, > > tag=t, > > ssize=ss, > > ename=e} > >> >> On Tue, Jun 2, 2009 at 4:20 PM, David Leimbach <[email protected]> wrote: >> > The thing is I have 19 bytes in the hex string I provided: >> > 1300000065ffff000400000600395032303030 >> > That's 38 characters or 19 bytes. >> > The last 4 are 9P2000 >> > 13000000 = 4 bytes for 32bit message payload, This is little endian >> > for 19 >> > bytes total. >> > 65 = 1 byte for message type. 65 is "Rversion" or the response type for >> > a >> > Tversion request >> > ffff = 2 bytes for 16bit message "tag". >> > >> > 00040000 = 4 bytes for the 32 bit maximum message payload size I'm >> > negotiating with the 9P server. This is little endian for 1024 >> > 0600 = 2 bytes for 16 bit value for the length of the "string" I'm >> > sending. >> > The strings are *NOT* null terminated in 9p, and this is little endian >> > for >> > 6 bytes remaining. >> > 5032303030 = 6 bytes the ASCII or UTF-8 string "9P2000" which is 6 bytes >> > 4 + 1 + 2 + 4 + 2 + 6 = 19 bytes. >> > As far as I can see, my "get" code does NOT ask for a 20th byte, so why >> > am I >> > getting that error? >> > get = do s <- getWord32le -- 4 >> > mtype <- getWord8 -- 1 >> > getSpecific s mtype >> > where >> > getSpecific s mt >> > | mt == mtRversion = do t <- getWord16le -- 2 >> > ms <- getWord32le -- 4 >> > ss <- getWord16le -- 2 >> > v <- >> > getRemainingLazyByteString -- remaining should be 6 bytes. >> > return $ MessageClient $ >> > Rversion {size=s, >> > >> > mtype=mt, >> > >> > tag=t, >> > >> > msize=ms, >> > >> > ssize=ss, >> > >> > version=v} >> > Should I file a bug? I don't believe I should be seeing an error >> > message >> > claiming a failure at the 20th byte when I've never asked for one. >> > Dave >> > >> > On Tue, Jun 2, 2009 at 10:51 AM, John Van Enk <[email protected]> wrote: >> >> >> >> Thomas, >> >> >> >> You're correct. For some reason, I based my advice on the thought that >> >> 19 was the minimum size instead of 13. >> >> >> >> On Tue, Jun 2, 2009 at 1:24 PM, Thomas DuBuisson >> >> <[email protected]> wrote: >> >> >> I think getRemainingLazyByteString expects at least one byte >> >> > No, it works with an empty bytestring. Or, my tests do with binary >> >> > 0.5.0.1. >> >> > >> >> > The specific error means you are requiring more data than providing. >> >> > First check the length of the bytestring you pass in to the to level >> >> > decode (or 'get') routine and walk though that to figure out how much >> >> > it should be consuming. I notice you have a guard on the >> >> > 'getSpecific' function, hopefully you're sure the case you gave us is >> >> > the branch being taken. >> >> > >> >> > I think the issue isn't with the code provided. I cleaned up the >> >> > code >> >> > (which did change behavior due to the guard and data declarations >> >> > that >> >> > weren't in the mailling) and it works fine all the way down to the >> >> > expected minimum of 13 bytes. >> >> > >> >> > >> >> >> import Data.ByteString.Lazy >> >> >> import Data.Binary >> >> >> import Data.Binary.Get >> >> >> >> >> >> data RV = >> >> >> Rversion { size :: Word32, >> >> >> mtype :: Word8, >> >> >> tag :: Word16, >> >> >> msize :: Word32, >> >> >> ssize :: Word16, >> >> >> version :: ByteString} >> >> >> deriving (Eq, Ord, Show) >> >> > >> >> >> instance Binary RV where >> >> >> get = do s <- getWord32le >> >> >> mtype <- getWord8 >> >> >> getSpecific s mtype >> >> >> where >> >> >> getSpecific s mt = do t <- getWord16le >> >> >> ms <- getWord32le >> >> >> ss <- getWord16le >> >> >> v <- getRemainingLazyByteString >> >> >> return $ Rversion {size=s, >> >> >> mtype=mt, >> >> >> tag=t, >> >> >> msize=ms, >> >> >> ssize=ss, >> >> >> version=v } >> >> >> put _ = undefined >> >> > >> >> >> >> >> >> >> >> -- >> >> /jve >> > >> > >> > _______________________________________________ >> > Haskell-Cafe mailing list >> > [email protected] >> > http://www.haskell.org/mailman/listinfo/haskell-cafe >> > >> > >> >> >> >> -- >> /jve > > -- /jve _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
