Compression and decompression of data streams in the gzip format.
The format is described in detail in RFC #1952: http://www.ietf.org/rfc/rfc1952.txt
See also the zlib home page: http://zlib.net/
This module provides pure functions for compressing and decompressing streams of data represented by lazy ByteStrings. This makes it easy to use either in memory or with disk or network IO.
For example a simple gzip compression program is just:
import qualified Data.ByteString.Lazy as ByteString import qualified Codec.Compression.GZip as GZip main = ByteString.interact GZip.compress
Or you could lazily read in and decompress a .gz file using:
content <- fmap GZip.decompress (readFile file)
|compress :: ByteString -> ByteString|
Compress a stream of data into the gzip format.
This uses the default compression level which favours a higher compression ratio over compression speed. Use compressWith to adjust the compression level.
|compressWith :: CompressionLevel -> ByteString -> ByteString|
Like compress but with an extra parameter to specify the compression level.
There are a number of additional compression parameters which are rarely necessary to change but if you need to you can do so using compressFull.
|decompress :: ByteString -> ByteString|
Decompress a stream of data in the gzip format.
There are a number of errors that can occur. In each case an exception will be thrown. The possible error conditions are:
Note that the decompression is performed lazily. Errors in the data stream may not be detected until the end of the stream is demanded (since it is only at the end that the final checksum can be checked). If this is important to you, you must make sure to consume the whole decompressed stream before doing any IO action that depends on it.
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