-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/
-- | Efficient in memory indexed database
--
-- Please see the README on GitHub at
-- https://github.com/pkamenarsky/memdb#readme
@package memdb
@version 1.0.0.2
module Multimap.ByteString
new :: IO Multimap
insert :: Multimap -> ByteString -> Word32 -> IO ()
lookup :: Multimap -> ByteString -> IO [Word32]
data Multimap
module Multimap.Word32
new :: IO Multimap
insert :: Multimap -> Word32 -> Word32 -> IO ()
lookup :: Multimap -> Word32 -> IO [Word32]
data Multimap
module Database.Immutable.Write
-- | Offset into the database.
newtype Id a
Id :: Word32 -> Id a
[getId] :: Id a -> Word32
-- | Limit the number of elements read after an Id.
newtype Limit a
Limit :: Word32 -> Limit a
[getLimit] :: Limit a -> Word32
-- | Increment Id.
incId :: Id a -> Id a
-- | Subtract two indexes, returning a Limit.
subIds :: Id a -> Id a -> Limit a
-- | Write data sequentially to a database file. Database files can be read
-- back using readDB.
--
-- An additional file path.meta is produced holding the number
-- of written elements.
writeDB :: Serialize a => FilePath -> ((a -> IO ()) -> IO r) -> IO r
-- | Creata a database from a list. Databases can be created back using
-- createDB.
fromList :: Serialize a => [a] -> ByteString
module Database.Immutable.Read
-- | Create a database from a ByteString and build up in-memory
-- indexes according to the Indexes description.
createDB :: forall indexes a. Serialize a => InsertIndex indexes a => ByteString -> Int -> Maybe (Int -> Int -> IO ()) -> Indexes indexes a -> IO (Either String (DB indexes a))
-- | Read a database from a file path and build up in-memory indexes
-- according to the Indexes description.
readDB :: forall indexes a. Serialize a => InsertIndex indexes a => FilePath -> Maybe (Int -> Int -> IO ()) -> Indexes indexes a -> IO (Either String (DB indexes a))
-- | Type tying a typelevel Symbol to a value.
--
-- Name has an IsLabel instance and can thus be created by
-- using the overloaded labels syntax (i.e. #someName) when the
-- OverloadedLabels GHC extension is enabled.
data Name (a :: Symbol)
-- | Indexes description. Currently, there are two supported index
-- types: Word32 and ByteString. Both can be specified
-- using the utility functions word32Index and
-- byteStringIndex, respectively.
--
-- For example, one might define indexes over a datatype in the following
-- way:
--
--
-- data Person = Person
-- { name :: String
-- , age :: Int
-- } deriving (Generic, Serialize)
--
-- personIndexes
-- = byteStringIndex #nameIndex (pack . name)
-- $ word32Index #ageIndex (fromIntegral . age)
-- unindexed
--
--
-- Composite or computed indexes can be built by supplying an appropriate
-- function to byteStringIndex or word32Index, e.g:
--
--
-- personIndexes
-- = byteStringIndex #nameAndAgePlusOneIndex
-- (\p -> pack (name p <> show (age p + 1)))
-- unindexed
--
data Indexes (indexes :: [(Symbol, *)]) a
-- | Default Indexes description, specifying an unindexed database.
unindexed :: Indexes '[] a
-- | Add a ByteString index to an Indexes description to be
-- built when reading a database.
byteStringIndex :: KnownSymbol s => Name s -> (a -> b) -> (b -> ByteString) -> Indexes indexes a -> Indexes ('(s, ByteStringIndex b) : indexes) a
-- | Add a Word32 index to an Indexes description to be built
-- when reading a database.
word32Index :: KnownSymbol s => Name s -> (a -> b) -> (b -> Word32) -> Indexes indexes a -> Indexes ('(s, Word32Index b) : indexes) a
-- | This package contains a thin wrapper over a continous memory region
-- combined with an efficient reverse index implementation for fast and
-- type-safe indexed lookups.
--
-- It is aimed at storing, loading and querying big immutable datasets.
-- Once written, a database can not be modified further.
--
-- The underlying storage is pinned and thus ensures efficient garbage
-- collection without ever reading the structure contents, since no
-- pointers live inside the dataset that point outside it.
module Database.Immutable
-- | An immutable database containing elements of type a, each one
-- indexed according to an Indexes description.
--
-- Import Database.Immutable.Read for reading boxed values and
-- Database.Immutable.Read.Unboxed for the unboxed variant.
data DB (indexes :: [(Symbol, *)]) a
data ByteStringIndex a
data Word32Index a
-- | Offset into the database.
newtype Id a
Id :: Word32 -> Id a
-- | Limit the number of elements read after an Id.
newtype Limit a
Limit :: Word32 -> Limit a
-- | O(1) Return number of records contained in the database.
length :: DB indexes a -> Limit a
-- | Zero Id.
zeroId :: Id a
-- | Increment Id.
incId :: Id a -> Id a
-- | Add a Limit to an Id.
addLimit :: Id a -> Limit a -> Id a
-- | Subtract two indexes, returning a Limit.
subIds :: Id a -> Id a -> Limit a
-- | O(1) Return the database element at the specified position.
(!) :: Serialize a => DB indexes a -> Id a -> Maybe a
-- | O(n) Return a slice of the database. The database must contain
-- at least i+n elements.
slice :: Serialize a => Id a -> Limit a -> DB indexes a -> [a]
-- | O(n) Lookup by index, n being the count of returned
-- elements.
--
-- Example:
--
--
-- lookup personsDB #nameIndex "Phil" -- Return all elements named "Phil"
--
lookup :: forall indexes s v a. Serialize a => LookupIndex indexes s v a => Name s -> v -> DB indexes a -> [a]