-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | Cross-platform structure serialisation -- -- This package parses and generates Haskell code for serialising and -- deserialising the tagging format in libevent 1.4. @package codec-libevent @version 0.1.2 module Codec.Libevent.Class class TaggedStructure a empty :: TaggedStructure a => a serialise :: TaggedStructure a => a -> ByteString deserialise :: TaggedStructure a => ByteString -> Either String a -- | This module parses libevent http://monkey.org/~provos/libevent -- tagged data structures as implimented in libevent-1.4.0-beta. These -- data structures are described in a .rpc file. module Codec.Libevent.Parse -- | This is a libevent .rpc file - just a list of the structures within data RPCFile RPCFile :: [RPCStruct] -> RPCFile rpcstructs :: RPCFile -> [RPCStruct] -- | An RPC structure has a name and a list of elements data RPCStruct RPCStruct :: String -> [RPCElem] -> RPCStruct structname :: RPCStruct -> String structelems :: RPCStruct -> [RPCElem] -- | An RPC element is a tagged member data RPCElem RPCElem :: Presence -> Type -> String -> Integer -> RPCElem elempresence :: RPCElem -> Presence elemtype :: RPCElem -> Type elemname :: RPCElem -> String elemtag :: RPCElem -> Integer data Presence Required :: Presence Optional :: Presence Repeated :: Presence data Type Bytes :: Int -> Type VarBytes :: Type String :: Type Int :: Type Struct :: String -> Type -- | Parse the given filename parseRPCFile :: FilePath -> IO (Either ParseError RPCFile) -- | Parse the given string as an RPC file parseRPC :: String -> Either ParseError RPCFile instance Eq Type instance Show Type instance Show Presence instance Show RPCElem instance Show RPCStruct instance Show RPCFile -- | This module generates Haskell code for serialising and deserialising -- libevent tagged data structures, as implemented in -- libevent-1.4.0-beta. -- -- A single .rpc file (containing one or more structures) is mapped to a -- single Haskell file. Take this example: -- -- 
--   struct test {
--     required int a = 1;
--     optional string b = 2;
--     repeated struct[test2] c = 3;
--   }
--
-- -- This will result in a data decl for Test, having named -- members: test_a, test_b and test_c. Required elements are simple, -- optional elements are wrapped in a Maybe and repeated elements in a -- list. -- -- Types are mapped thus: -- -- -- -- In the example above, test2 is required to be in the same -- .rpc file. -- -- For a structure named test, the following would also be -- generated: -- -- -- -- Each structure will also be an instance of the -- TaggedStructure class that you can find in -- Codec.Libevent.Class module Codec.Libevent.Generate -- | Generate the Haskell code for the given RPC file and write to standard -- out. The generated module will export everything and takes the given -- name generate :: String -> RPCFile -> IO () -- | Tagged data structures are an extensible way of serialising data in a -- platform independent way for transmission across a network etc. This -- package implements the tagged structures from libevent 1.4.0-beta. -- -- A tagged structure is described in a text file and might look like -- this: -- -- 
--   struct foo {
--     required int count = 1;
--     optional struct[bar] names = 2;
--   }
--   
--   struct bar {
--     repeated string s = 1;
--   }
--
-- -- The numbers after the equals signs are the tag numbers for each -- element of a structure. The tag numbers must be unique within a -- structure and should be sequenctial (but are not required to be). -- -- The tag numbers must also be fixed for all time. When deserialising, -- unknown tags are ignored. Thus one can add a new (non-required) -- element to foo in the future and still interoperate with -- older code which knows nothing of the new element. -- -- Each element in the description looks like: -- -- 
--   <presence> <type> <name> = <tag number> ;
--
-- -- The possible presence values are: required, optional -- and repeated. The types are (currently): int, -- string, struct[NAME] and bytes. -- -- Other modules in this package parse these descriptions and -- automatically generate Haskell code for them. You should have a binary -- called codec-libevent-generate which does this. See the -- documentation for Codec.Libevent.Generate about the structure -- of the generated code. -- -- Once you have generated the code, you can import it as a regular -- Haskell module and serialise/deserialise these structures. You can -- also use the libevent library to process them in C. -- -- This module contains helper functions and is imported by the code -- generated by Codec.Libevent.Generate. Apart from the -- TaggedStructure class, there's probably not anything -- generally useful here. module Codec.Libevent -- | Decode a base128 encoded integer. This is a variable length encoded -- int where the last byte has the MSB set to 0. getBase128 :: Get Word32 -- | Encode a integer in Base128 form putBase128 :: Word32 -> Put -- | Decode a number where the first nibble of the first byte is the number -- of nibbles in the number. The remaining nibbles appear in -- little-endian order following, with 0 padding to the nearest byte. getLengthPrefixed :: Get Word32 -- | Return the number of nibbles, n, required to encode a given number. n -- >= 1 nibbleLength :: Word32 -> Int -- | Encode a Word32 by prefixing the number of nibbles and following with -- the nibbles of the number in little-endian order putLengthPrefixed :: Word32 -> Put -- | Return the length of the length-prefixed representation of a Word32 lengthPrefixedLength :: Word32 -> Int putTaggedWord32 :: Word32 -> Word32 -> Put putTaggedString :: Word32 -> String -> Put putTaggedVarBytes :: Word32 -> ByteString -> Put decodeString :: ByteString -> String