Database.TokyoCabinet.HDB

Contents

Basic API (tokyocabinet.idl compliant)

Description

Interface to Hash based DBM. See also, http://tokyocabinet.sourceforge.net/spex-en.html#tchdbapi for details

Synopsis

Documentation

Example

    import Control.Monad
    import Database.TokyoCabinet.HDB

    main = do hdb <- new
              -- open the database
              open hdb "casket.tch" [OWRITER, OCREAT] >>= err hdb
              -- store records
              puts hdb [("foo", "hop"), ("bar", "step"), ("baz", "jump")] >>=
                       err hdb . (all id)
              -- retrieve records
              get_print hdb "foo"
              -- traverse records
              iterinit hdb
              iter hdb >>= mapM_ (k -> putStr (k++":") >> get_print hdb k)
              -- close the database
              close hdb >>= err hdb
        where
          puts :: HDB -> [(String, String)] -> IO [Bool]
          puts hdb = mapM (uncurry $ put hdb)

          get_print :: HDB -> String -> IO ()
          get_print hdb key = get hdb key >>=
                              maybe (error "something goes wrong") putStrLn

  
          err :: HDB -> Bool -> IO ()
          err hdb = flip unless $ ecode hdb >>= error . show

    
          iter :: HDB -> IO [String]
          iter hdb = iternext hdb >>=
                     maybe (return []) (x -> return . (x:) =<< iter hdb)

data HDB Source

Instances

TCDB HDB

data ECODE Source

Represents error

Constructors

ESUCCESS	success
ETHREAD	threading error
EINVALID	invalid operation
ENOFILE	file not found
ENOPERM	no permission
EMETA	invalid meta data
ERHEAD	invalid record header
EOPEN	open error
ECLOSE	close error
ETRUNC	trunc error
ESYNC	sync error
ESTAT	stat error
ESEEK	seek error
EREAD	read error
EWRITE	write error
EMMAP	mmap error
ELOCK	lock error
EUNLINK	unlink error
ERENAME	rename error
EMKDIR	mkdir error
ERMDIR	rmdir error
EKEEP	existing record
ENOREC	no record found
EMISC	miscellaneous error

Instances

Eq ECODE
Ord ECODE
Show ECODE

data OpenMode Source

Constructors

OREADER
OWRITER
OCREAT
OTRUNC
ONOLCK
OLCKNB
OTSYNC

Instances

Eq OpenMode
Ord OpenMode
Show OpenMode

data TuningOption Source

Constructors

TLARGE
TDEFLATE
TBZIP
TTCBS
TEXCODEC

Instances

Eq TuningOption
Ord TuningOption
Show TuningOption

Basic API (tokyocabinet.idl compliant)

new :: IO HDB Source

Create a Hash database object.

delete :: HDB -> IO ()Source

Free HDB resource forcibly. HDB is kept by ForeignPtr, so Haskell runtime GC cleans up memory for almost situation. Most always, you don't need to call this. After call this, you must not touch HDB object. Its behavior is undefined.

ecode :: HDB -> IO ECODE Source

Return the last happened error code.

errmsg :: ECODE -> String Source

Convert error code to message string.

tune Source

Arguments

:: HDB	HDB object
-> Int64	the number of elements of the bucket array.
-> Int8	the size of record alignment by power of 2.
-> Int8	the maximum number of elements of the free block pool by power of 2.
-> [TuningOption]	tuning options.
-> IO Bool	if successful, the return value is True.

Set the tuning parameters.

setcache Source

Arguments

:: HDB	HDB object.
-> Int32	the maximum number of records to be cached.
-> IO Bool	if successful, the return value is True.

Set the caching parameters.

setxmsiz :: HDB -> Int64 -> IO Bool Source

Set the size of extra mapped memory.

open :: HDB -> String -> [OpenMode] -> IO Bool Source

Open a database file.

close :: HDB -> IO Bool Source

Close the database file.

put :: (Storable k, Storable v) => HDB -> k -> v -> IO Bool Source

Stora a record (key-value pair) on HDB. Key and value type must be instance of Storable class. Usually, we can use String, ByteString for key, String, ByteString, Int, Double for value.

putkeep :: (Storable k, Storable v) => HDB -> k -> v -> IO Bool Source

Store a new record. If a record with the same key exists in the database, this function has no effect.

putcat :: (Storable k, Storable v) => HDB -> k -> v -> IO Bool Source

Concatenate a value at the end of the existing record.

putasync :: (Storable k, Storable v) => HDB -> k -> v -> IO Bool Source

Store a record into a hash database object in asynchronous fashion.

out :: Storable k => HDB -> k -> IO Bool Source

Delete a record.

get :: (Storable k, Storable v) => HDB -> k -> IO (Maybe v)Source

Return the value of record.

vsiz :: Storable k => HDB -> k -> IO (Maybe Int)Source

Return the byte size of value in a record.

iterinit :: HDB -> IO Bool Source

Initialize the iterator of a HDB object.

iternext :: Storable k => HDB -> IO (Maybe k)Source

Return the next key of the iterator of a HDB object.

fwmkeys :: (Storable k1, Storable k2, Sequence q) => HDB -> k1 -> Int -> IO (q k2)Source

Return list of forward matched keys.

addint :: Storable k => HDB -> k -> Int -> IO (Maybe Int)Source

Increment the corresponding value. (The value specified by a key is treated as integer.)

adddouble :: Storable k => HDB -> k -> Double -> IO (Maybe Double)Source

Increment the corresponding value. (The value specified by a key is treated as double.)

sync :: HDB -> IO Bool Source

Synchronize updated contents of a database object with the file and the device.

optimize Source

Arguments

:: HDB	HDB object
-> Int64	the number of elements of the bucket array.
-> Int8	the size of record alignment by power of 2.
-> Int8	the maximum number of elements of the free block pool by power of 2.
-> [TuningOption]	tuning options.
-> IO Bool	if successful, the return value is True.

Optimize the file of a Hash database object.

vanish :: HDB -> IO Bool Source

Delete all records.

copy :: HDB -> String -> IO Bool Source

Copy the database file.

tranbegin :: HDB -> IO Bool Source

Begin the transaction.

trancommit :: HDB -> IO Bool Source

Commit the transaction.

tranabort :: HDB -> IO Bool Source

Abort the transaction.

path :: HDB -> IO (Maybe String)Source

Return the file path of currentry opened database.

rnum :: HDB -> IO Word64 Source

Return the number of records in the database.

fsiz :: HDB -> IO Word64 Source

Return the size of the database file.