Flat.Decoder.Prim

Strict Decoder Primitives

Documentation

dBool :: Get Bool

Decode a boolean

dWord8 :: Get Word8

Return the 8 most significant bits (same as dBE8)

dBE8 :: Get Word8

Return the 8 most significant bits

dBE16 :: Get Word16

Return the 16 most significant bits

dBE32 :: Get Word32

Return the 32 most significant bits

dBE64 :: Get Word64

Return the 64 most significant bits

dBEBits8 :: Int -> Get Word8

Return the n most significant bits (up to maximum of 8)

The bits are returned right shifted:

>>> unflatWith (dBEBits8 3) [0b11100001::Word8] == Right 0b00000111
True

>>> unflatWith (dBEBits8 9) [0b11100001::Word8,0b11111111]
Left (BadOp "read8: cannot read 9 bits")

dBEBits16 :: Int -> Get Word16

Return the n most significant bits (up to maximum of 16)

The bits are returned right shifted:

>>> pPrint . asBits <$> unflatWith (dBEBits16 11) [0b10110111::Word8,0b11100001]
Right 00000101 10111111

If more than 16 bits are requested, only the last 16 are returned:

>>> pPrint . asBits <$> unflatWith (dBEBits16 19) [0b00000000::Word8,0b11111111,0b11100001]
Right 00000111 11111111

dBEBits32 :: Int -> Get Word32

Return the n most significant bits (up to maximum of 32) The bits are returned right shifted.

dBEBits64 :: Int -> Get Word64

Return the n most significant bits (up to maximum of 64) The bits are returned right shifted.

dropBits :: Int -> Get ()

Drop the specified number of bits

dFloat :: Get Float

Decode a Float

dDouble :: Get Double

Decode a Double

getChunksInfo :: Get (Ptr Word8, [Int])

Decode an Array (a list of chunks up to 255 bytes long) returning the pointer to the first data byte and a list of chunk sizes

dByteString_ :: Get ByteString

Decode a ByteString

dLazyByteString_ :: Get ByteString

Decode a Lazy ByteString

dByteArray_ :: Get (ByteArray, Int)

Decode a ByteArray and its length

data ConsState

A special state, optimised for constructor decoding.

It consists of:

• The bits to parse, the top bit being the first to parse (could use a Word16 instead, no difference in performance)
• The number of decoded bits

Supports up to 512 constructors (9 bits).

Constructors

ConsState !Word !Int

consOpen :: Get ConsState

Switch to constructor decoding {-# INLINE consOpen #-}

consClose :: Int -> Get ()

Switch back to normal decoding {-# NOINLINE consClose #-}

consBool :: ConsState -> (ConsState, Bool)

Decode a single bit

consBits :: ConsState -> Int -> (ConsState, Word)

Decode from 1 to 3 bits

It could read more bits that are available, but it doesn't matter, errors will be checked in consClose.

sizeOf :: Get a -> Get Int

Given a value's decoder, returns the size in bits of the encoded value

Since: 0.6

binOf :: Get a -> Get (ByteString, Int)

Given a value's decoder, returns the value's bit encoding.

The encoding starts at the returned bit position in the return bytestring's first byte and ends in an unspecified bit position in its final byte

Since: 0.6