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-- Copyright (c) 2016-present, Facebook, Inc.
-- All rights reserved.
--
-- This source code is licensed under the BSD-style license found in
-- the LICENSE file in the root directory of this source tree. An
-- additional grant of patent rights can be found in the PATENTS file
-- in the same directory.
-- |
-- Module : Codec.Compression.Zstd
-- Copyright : (c) 2016-present, Facebook, Inc. All rights reserved.
--
-- License : BSD3
-- Maintainer : bryano@fb.com
-- Stability : experimental
-- Portability : GHC
--
-- A fast lossless compression algorithm, targeting real-time
-- compression scenarios at zlib-level and better compression ratios.
module Codec.Compression.Zstd
(
-- * Basic pure API
compress
, Decompress(..)
, decompressedSize
, decompress
, C.maxCLevel
-- * Dictionary-based compression
, Dict
, mkDict
, fromDict
, trainFromSamples
, getDictID
-- ** Basic pure API
, compressUsingDict
, decompressUsingDict
) where
import Codec.Compression.Zstd.Internal
import Codec.Compression.Zstd.Types (Decompress(..), Dict(..), mkDict)
import Data.ByteString.Internal (ByteString(..))
import System.IO.Unsafe (unsafePerformIO)
import qualified Codec.Compression.Zstd.FFI as C
-- | Compress the given data as a single zstd compressed frame.
compress :: Int
-- ^ Compression level. Must be >= 1 and <= 'C.maxCLevel'.
-> ByteString
-- ^ Payload to compress.
-> ByteString
compress level bs = unsafePerformIO $
compressWith "compress" C.compress level bs
-- | Decompress a single-frame payload of known size. Typically this
-- will be a payload that was compressed with 'compress'.
--
-- /Note:/ This function is not capable of decompressing a payload
-- generated by the streaming or lazy compression APIs.
decompress :: ByteString -> Decompress
decompress bs = unsafePerformIO $ decompressWith C.decompress bs
-- | Compress the given data as a single zstd compressed frame, using
-- a prebuilt dictionary.
compressUsingDict :: Dict
-- ^ Compression dictionary.
-> Int
-- ^ Compression level. Must be >= 1 and <= 'C.maxCLevel'.
-> ByteString
-- ^ Payload to compress.
-> ByteString
compressUsingDict dict level bs =
unsafePerformIO . withCCtx $ \(CCtx ctx) ->
withDict dict $ \dictPtr dictLen ->
let compressor dp dl sp sl l =
C.compressUsingDict ctx dp dl sp sl dictPtr dictLen l
in compressWith "compressUsingDict" compressor level bs
-- | Decompress a single-frame payload of known size, using a prebuilt
-- dictionary. Typically this will be a payload that was compressed
-- with 'compressUsingDict'.
--
-- /Note:/ This function is not capable of decompressing a payload
-- generated by the streaming or lazy compression APIs.
decompressUsingDict :: Dict
-- ^ Dictionary.
-> ByteString
-- ^ Payload to decompress.
-> Decompress
decompressUsingDict dict bs =
unsafePerformIO . withDCtx $ \(DCtx ctx) ->
withDict dict $ \dictPtr dictLen ->
let decompressor dp dl sp sl =
C.decompressUsingDict ctx dp dl sp sl dictPtr dictLen
in decompressWith decompressor bs
|
