Codec.Compression.Snappy.Framing

Exported Types

type Checksum = Word32

data Chunk

Constructors

StreamIdentifier

Compressed !Checksum !ByteString

Uncompressed !Checksum !ByteString

Skippable !Word8

Unskippable !Word8

Instances

Eq Chunk

Show Chunk

Binary Chunk

type DecodeError = (ByteOffset, String)

Encoding and Decoding

encode :: ByteString -> (Chunk, Maybe ByteString)

Encode a lazy ByteString into a Chunk

If the input is longer than minCompressible bytes, the resulting chunk is Compressed otherwise Uncompressed. If the input size exceeds maxUncompressed bytes, the leftover input is returned in a Just.

encode' :: ByteString -> (Chunk, Maybe ByteString)

Encode a strict ByteString into a Chunk

If the input is longer than minCompressible bytes, the resulting chunk is Compressed otherwise Uncompressed. If the input size exceeds maxUncompressed bytes, the leftover input is returned in a Just.

decode :: ByteString -> (Either DecodeError Chunk, Maybe ByteString)

Decode a lazy ByteString into a Chunk

decode' :: ByteString -> (Either DecodeError Chunk, Maybe ByteString)

Decode a strict ByteString into a Chunk

decodeVerify :: ByteString -> (Either DecodeError Chunk, Maybe ByteString)

Decode a lazy ByteString into a Chunk and verify the result

decodeVerify' :: ByteString -> (Either DecodeError Chunk, Maybe ByteString)

Decode a strict ByteString into a Chunk and verify the result

decodeM

Arguments

:: Monad m

=> m (Maybe ByteString)

And action that will be run to provide input. If it returns Nothing it is assumed no more input is available.

-> m (Either DecodeError Chunk, Maybe ByteString)

Either a parse error or a Chunk, along with leftovers if any.

Decode drawing input from the given monadic action as needed

decodeVerifyM :: Monad m => m (Maybe ByteString) -> m (Either DecodeError Chunk, Maybe ByteString)

Like decodeM, but verify the result

Utility functions

checksum :: ByteString -> Checksum

Compute a masked CRC32C checksum of the input

streamIdentifier :: ByteString

Yield a stream identifier (start-of-stream marker)

verify :: Chunk -> Maybe Chunk

Verify a Chunk

Returns Nothing if the input is an Unskippable chunk, or the checksum verification fails (if the input is a Compressed or Uncompressed chunk). Otherwise, the input Chunk is returned in a Just. Note that Compressed chunks are decompressed into Uncompressed chunks on the fly.