Data.Digest.Adler32

An implementation of the Adler-32 checksum algorithm. There are two ways to use this module:

• adler32 and adler32Update which use Word32 for checksums,
• adler32' and adler32Update' which use the abstract type Adler32 for checksums. This mode is slightly more low-level (extractAdler32 has to be used to obtain a Word32 for the checksum), but it supports some additional operations such rolling checksum and compounding.

Documentation

class Adler32Src a where

Types of messages for which the Adler-32 checksum can be computed.

Minimal complete definition

adler32Update'

Methods

adler32 :: a -> Word32

Compute the Adler-32 checksum of a ByteString.

adler32Update :: Word32 -> a -> Word32

Update the checksum of a message by providing a ByteString to be appended to the original message.

adler32' :: a -> Adler32

Similar to adler32 except that an Adler32 value is returned.

adler32Update' :: Adler32 -> a -> Adler32

Similar to adler32update except that it operates on Adler32 values. An Adler32 value can also be updated with adler32' in conjunction with the Monoid instance of that type.

Instances

Adler32Src ByteString

Methods

adler32 :: ByteString -> Word32

adler32Update :: Word32 -> ByteString -> Word32

adler32' :: ByteString -> Adler32

adler32Update' :: Adler32 -> ByteString -> Adler32

Adler32Src ByteString

Methods

adler32 :: ByteString -> Word32

adler32Update :: Word32 -> ByteString -> Word32

adler32' :: ByteString -> Adler32

adler32Update' :: Adler32 -> ByteString -> Adler32

data Adler32

An abstract representation of an Adler-32 checksum. Forcing a value of this type to whnf will cause it to be evaluated completely.

Instances

Eq Adler32

Methods

(==) :: Adler32 -> Adler32 -> Bool

(/=) :: Adler32 -> Adler32 -> Bool

Ord Adler32

Methods

compare :: Adler32 -> Adler32 -> Ordering

(<) :: Adler32 -> Adler32 -> Bool

(<=) :: Adler32 -> Adler32 -> Bool

(>) :: Adler32 -> Adler32 -> Bool

(>=) :: Adler32 -> Adler32 -> Bool

max :: Adler32 -> Adler32 -> Adler32

min :: Adler32 -> Adler32 -> Adler32

Show Adler32

Methods

showsPrec :: Int -> Adler32 -> ShowS

show :: Adler32 -> String

showList :: [Adler32] -> ShowS

Semigroup Adler32

Methods

(<>) :: Adler32 -> Adler32 -> Adler32

sconcat :: NonEmpty Adler32 -> Adler32

stimes :: Integral b => b -> Adler32 -> Adler32

Monoid Adler32

mempty is the checksum of the empty message and <> computes the checksum of the concatenation of two messages. <> is an O(1) operation.

Methods

mempty :: Adler32

mappend :: Adler32 -> Adler32 -> Adler32

mconcat :: [Adler32] -> Adler32

extractAdler32 :: Adler32 -> Word32

Extract the actual Adler-32 checksum from a Adler32 object.

makeAdler32 :: Integral a => Word32 -> a -> Adler32

makeAdler32 c l will create an Adler32 object that corresponds to a message whose checksum is c and length is l.

adler32SlideL :: Word8 -> Adler32 -> Word8 -> Adler32

O(1). If c is the checksum of a message that starts with the byte d1 then adler32SlideL d1 c d2 is the checksum of the message that is obtained by removing the first byte and appending the byte d2 at the end of the original message. It is the caller's responsibility to ensure that the original message starts with the byte d1.

adler32SlideR :: Word8 -> Adler32 -> Word8 -> Adler32

O(1). Similar to adler32SlideL except that it slides the checksum window to the other direction, i.e. in adler32SlideR d1 c d2 the byte d2 will be removed from the end of the original message and the byte d1 will be prepended to its beginning. It is the caller's responsibility to ensure that the original message ends with the byte d2.

adler32AppendByte :: Adler32 -> Word8 -> Adler32

O(1). Given the checksum of a message, this function returns the checksum of that message with a byte appended to it.

adler32UnAppendByte :: Adler32 -> Word8 -> Adler32

O(1). Given the checksum of a message, this function returns the checksum of that message its last byte removed from it. The value of that byte has to be provided by the caller and the behavior of the function is unspecified if that value is incorrect.

adler32PrependByte :: Word8 -> Adler32 -> Adler32

O(1). Given the checksum of a message, this function returns the checksum of that message with a byte prepended to it.

adler32UnPrependByte :: Word8 -> Adler32 -> Adler32

O(1). Given the checksum of a message, this function returns the checksum of that message its first byte removed from it. The value of that byte has to be provided by the caller and the behavior of the function is unspecified if that value is incorrect.

adler32UnAppend :: Adler32 -> Adler32 -> Adler32

O(1). If s1 and s2 are two messages then adler32UnAppend c c2 returns the checksum of s1 where c is the checksum of s1 <> s2 and c2 is the checksum of s2.

adler32UnPrepend :: Adler32 -> Adler32 -> Adler32

O(1). If s1 and s2 are two messages then adler32UnAppend c1 c returns the checksum of s2 where c is the checksum of s1 <> s2 and c1 is the checksum of s1.