| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Data.Vector.Compact.Blob
Contents
Description
Blobs are raw data in continuous regions of memory.
This library provides a type for blobs consisting 64 bit words which is optimized for small sizes. They take:
- only 1 extra word up for blobs of size up to 48 bytes (that is, up to 6
Word64-s); - but (unfortunataly) 4 extra words above that.
(This particular tradeoff was chosen so that pointer tagging still works on 64 bit architectures: there are 7 constructors of the data type.)
The Blob data type is useful if you want to store large amounts of small,
serialized data. Some example use cases:
- small vectors of small nonnegative integers (for example: partitions, permutations, monomials)
- cryptographic hashes
- tables indexed by such things
Synopsis
- data Blob
- blobTag :: Blob -> Int
- blobSizeInWords :: Blob -> Int
- blobSizeInBytes :: Blob -> Int
- blobSizeInBits :: Blob -> Int
- blobFromWordList :: [Word64] -> Blob
- blobFromWordListN :: Int -> [Word64] -> Blob
- blobToWordList :: Blob -> [Word64]
- blobFromByteArray :: ByteArray -> Blob
- blobToByteArray :: Blob -> ByteArray
- eqBlob :: Blob -> Blob -> Bool
- newtype Hex = Hex Word64
- hexWord64 :: Word64 -> String
- hexWord64_ :: Word64 -> String
- peekWord :: Blob -> Int -> Word64
- peekByte :: Blob -> Int -> Word8
- blobHead :: Blob -> Word64
- extractSmallWord :: Integral a => Int -> Blob -> Int -> a
- extractSmallWord64 :: Int -> Blob -> Int -> Word64
- extractSmallWord64_naive :: Int -> Blob -> Int -> Word64
- extendToSize :: Int -> Blob -> Blob
- cutToSize :: Int -> Blob -> Blob
- forceToSize :: Int -> Blob -> Blob
- mapBlob :: (Word64 -> Word64) -> Blob -> Blob
- shortZipWith :: (Word64 -> Word64 -> Word64) -> Blob -> Blob -> Blob
- longZipWith :: (Word64 -> Word64 -> Word64) -> Blob -> Blob -> Blob
- unsafeZipWith :: (Word64 -> Word64 -> Word64) -> Blob -> Blob -> Blob
the Blob type
A Blob is a nonempty array of Word64-s.
For arrays of length at most 6 (that is, at most 48 bytes), there is only a single
machine word overhead in memory consumption. For larger arrays, there is 4 words of overhead.
Constructors
| Blob1 !Word64 | |
| Blob2 !Word64 !Word64 | |
| Blob3 !Word64 !Word64 !Word64 | |
| Blob4 !Word64 !Word64 !Word64 !Word64 | |
| Blob5 !Word64 !Word64 !Word64 !Word64 !Word64 | |
| Blob6 !Word64 !Word64 !Word64 !Word64 !Word64 !Word64 | |
| BlobN !ByteArray# |
Instances
| Eq Blob Source # | |
| Show Blob Source # | |
| Bits Blob Source # | |
Defined in Data.Vector.Compact.Blob Methods (.&.) :: Blob -> Blob -> Blob # (.|.) :: Blob -> Blob -> Blob # complement :: Blob -> Blob # shift :: Blob -> Int -> Blob # rotate :: Blob -> Int -> Blob # setBit :: Blob -> Int -> Blob # clearBit :: Blob -> Int -> Blob # complementBit :: Blob -> Int -> Blob # testBit :: Blob -> Int -> Bool # bitSizeMaybe :: Blob -> Maybe Int # shiftL :: Blob -> Int -> Blob # unsafeShiftL :: Blob -> Int -> Blob # shiftR :: Blob -> Int -> Blob # unsafeShiftR :: Blob -> Int -> Blob # rotateL :: Blob -> Int -> Blob # | |
| FiniteBits Blob Source # | |
Defined in Data.Vector.Compact.Blob Methods finiteBitSize :: Blob -> Int # countLeadingZeros :: Blob -> Int # countTrailingZeros :: Blob -> Int # | |
blobSizeInBytes :: Blob -> Int Source #
blobSizeInBits :: Blob -> Int Source #
Conversion to/from lists
blobFromWordList :: [Word64] -> Blob Source #
blobToWordList :: Blob -> [Word64] Source #
Conversion to/from ByteArray-s
blobFromByteArray :: ByteArray -> Blob Source #
Note: we pad the input with zero bytes, assuming little-endian architecture.
blobToByteArray :: Blob -> ByteArray Source #
Hexadecimal
hexWord64_ :: Word64 -> String Source #
Peek
peekByte :: Blob -> Int -> Word8 Source #
NOTE: We assume a little-endian architecture here. Though it seems that since GHC does not gives us direct access to the closure, it doesn't matter after all...
extractSmallWord :: Integral a => Int -> Blob -> Int -> a Source #
extractSmallWord n blob ofs extracts a small word of n bits starting from the
ofs-th bit. This should satisfy
testBit (extractSmallWord n blob ofs) i == testBit blob (ofs+i)
NOTE: we assume that n is at most the bits in Word, and that ofs+n is less
than the size (in bits) of the blob.
extractSmallWord64_naive :: Int -> Blob -> Int -> Word64 Source #
An alternate implementation using testBit, for testing purposes only