|Portability||portable (H98 + FFI)|
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 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
Control amount of compression. This is a trade-off between the amount of compression and the time and memory required to do the compression.
The default compression level is 6 (that is, biased towards high compression at expense of speed).
No compression, just a block copy.
The fastest compression method (less compression)
The slowest compression method (best compression).
A specific compression level between 1 and 9.
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:
- if the stream does not start with a valid gzip header
- if the compressed stream is corrupted
- if the compressed stream ends permaturely
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.