At Thu, 25 May 2006 13:42:11 +0400, Bulat Ziganshin wrote:
Hello Jeremy,
Monday, May 22, 2006, 12:20:54 AM, you wrote:
For my own needs, I cabalized and debianized the Streams library. It generates binary debs for ghc6 and hugs -- but I think the hugs version is broken. In any case, it is a start, you can download the packaging at:
can i include your work in the library itself?
Absolutely.
is it better to include 'debian' directory to my archive or left this to the debian packagers?
If someone volunteers to maintain the package -- then it is probably better to not keep a copy of the debian directory in your archive -- because it will often be out of date and confuse people -- and debian users will be able to get the debianized source easily by typing, 'apt-get source haskell-streams'. On the other hand -- if there is no one officially maintaing it -- it would be useful to provide the debian directory (with a disclaimer) so that debian users can easily build and install the .deb, since subverting the debian package system tends to lead to long-term complications.
can you say how you are use my library? it's both interesting for me and can be helpful in deciding how it should be further developed
I am using it to serialize/deserialize haskell data structures so I can store them in a Berkeley database. To get them into BDB I need to convert the haskell data structure into a C structure that looks like this: struct __db_dbt { void *data; /* Key/data */ u_int32_t size; /* key/data length */ }; Currently I am doing it like this -- but this will clearly fail if the serialized data structure is longer than 512 bytes... withDBT :: (Binary a) => a -> (Ptr DBT -> IO b) -> IO b withDBT thedata f = allocaBytes #{size DBT} $ \dbtPtr -> allocaBytes 512 $ \dataPtr -> do h <- openMemBuf dataPtr 512 withByteAlignedLE h $ flip put_ thedata wrote <- vTell h vClose h #{poke DBT, data} dbtPtr (castPtr dataPtr) #{poke DBT, size} dbtPtr ((fromIntegral wrote) :: Int) f dbtPtr I don't really need the file-system interface for this project -- what would be nice is something like 'withCStringLen' and 'peekCString' for the encode/decode functions: type PtrLen a = (Ptr a, Int) encodePtrLen :: (Binary a) => a -> (PtrLen a -> IO b) -> IO b decodePtr :: (Binary a) => Ptr a -> IO a I could simulate this by using 'encode' to convert the data structure to a String and then use 'withCStringLen' to get the pointer and length -- but having the intermediate String seems like it could be a big performance hit. Two alternative ideas are: (1) accurately pre-calculate the size of the serialized structure and allocate the correct amount of memory from the start (2) start with a 'guess' and realloc the memory if the initial guess is too small. Both of those alternatives have their own problems -- so I think only testing will tell what works best... I have not looked at the library exhaustively, so if there is already a good way to do this, let me know. Thanks! j.