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{-| Provides interface to the 'zlib' library.

-}

{-

Copyright (C) 2014 Google Inc.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301, USA.

-}

module Ganeti.Codec

  ( compressZlib

  , decompressZlib

  ) where

import Codec.Compression.Zlib (compress)

import qualified Codec.Compression.Zlib.Internal as I

import Control.Monad.Error

import qualified Data.ByteString.Lazy as BL

import qualified Data.ByteString.Lazy.Internal as BL

import Data.Monoid (mempty)

-- | Compresses a lazy bytestring.

compressZlib :: BL.ByteString -> BL.ByteString

compressZlib = compress

-- | Decompresses a lazy bytestring, throwing decoding errors using

-- 'throwError'.

decompressZlib :: (MonadError e m, Error e) => BL.ByteString -> m BL.ByteString

decompressZlib = I.foldDecompressStream

                     (liftM . BL.chunk)

                     (return mempty)

                     (const $ throwError . strMsg . ("Zlib: " ++))

                 . I.decompressWithErrors

                     I.zlibFormat

                     I.defaultDecompressParams