Flat.Instances.ByteString

Flat instances for the bytestring library

Orphan instances

Flat ShortByteString

>>> tst ((False,True,False,SBS.pack [11,22,33]))
(True,51,[65,3,11,22,33,0])

Methods

encode :: ShortByteString -> Encoding

decode :: Get ShortByteString

size :: ShortByteString -> NumBits -> NumBits

Flat ByteString

>>> tst ((False,True,False,L.pack [11,22,33]))
(True,51,[65,3,11,22,33,0])

Methods

encode :: ByteString -> Encoding

decode :: Get ByteString

size :: ByteString -> NumBits -> NumBits

Flat ByteString

ByteString, ByteString.Lazy and ByteString.Short are all encoded as Prealigned Arrays:

PreAligned a ≡ PreAligned {preFiller :: Filler, preValue :: a}

Filler ≡   FillerBit Filler
          | FillerEnd

Array v = A0
        | A1 v (Array v)
        | A2 v v (Array v)
        ...
        | A255 ... (Array v)

That's to say as a byte-aligned sequence of blocks of up to 255 elements, with every block preceded by the count of the elements in the block and a final 0-length block.

>>> tst (B.pack [11,22,33])
(True,48,[1,3,11,22,33,0])

where:

1= PreAlignment (takes a byte if we are already on a byte boundary)

3= Number of bytes in ByteString

11,22,33= Bytes

0= End of Array

>>> tst (B.pack [])
(True,16,[1,0])

Pre-alignment ensures that a ByteString always starts at a byte boundary:

>>> tst ((False,True,False,B.pack [11,22,33]))
(True,51,[65,3,11,22,33,0])

All ByteStrings are encoded in the same way:

>>> all (tst (B.pack [55]) ==) [tst (L.pack [55]),tst (SBS.pack [55])]
True

Methods

encode :: ByteString -> Encoding

decode :: Get ByteString

size :: ByteString -> NumBits -> NumBits