Codec.CBOR.Decoding

cborg-0.2.10.0: Concise Binary Object Representation (CBOR)

Copyright | (c) Duncan Coutts 2015-2017
License | BSD3-style (see LICENSE.txt)
Maintainer | duncan@community.haskell.org
Stability | experimental
Portability | non-portable (GHC extensions)
Safe Haskell | None
Language | Haskell2010

Codec.CBOR.Decoding

Contents

- Decode primitive operations
  - Read input tokens
  - Specialised Read input token operations
  - Branching operations
  - Inspecting the token type
  - Special operations
  - Canonical CBOR
- Sequence operations

Description

High level API for decoding values that were encoded with the Codec.CBOR.Encoding module, using a `Monad` based interface.

Synopsis

- data Decoder s a
- data DecodeAction s a
  - = ConsumeWord (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord8 (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord16 (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord32 (Word# -> ST s (DecodeAction s a))
  - | ConsumeNegWord (Word# -> ST s (DecodeAction s a))
  - | ConsumeInt (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt8 (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt16 (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt32 (Int# -> ST s (DecodeAction s a))
  - | ConsumeListLen (Int# -> ST s (DecodeAction s a))
  - | ConsumeMapLen (Int# -> ST s (DecodeAction s a))
  - | ConsumeTag (Word# -> ST s (DecodeAction s a))
  - | ConsumeInteger (Integer -> ST s (DecodeAction s a))
  - | ConsumeFloat (Float# -> ST s (DecodeAction s a))
  - | ConsumeDouble (Double# -> ST s (DecodeAction s a))
  - | ConsumeBytes (ByteString -> ST s (DecodeAction s a))
  - | ConsumeByteArray (ByteArray -> ST s (DecodeAction s a))
  - | ConsumeString (Text -> ST s (DecodeAction s a))
  - | ConsumeUtf8ByteArray (ByteArray -> ST s (DecodeAction s a))
  - | ConsumeBool (Bool -> ST s (DecodeAction s a))
  - | ConsumeSimple (Word# -> ST s (DecodeAction s a))
  - | ConsumeBytesIndef (ST s (DecodeAction s a))
  - | ConsumeStringIndef (ST s (DecodeAction s a))
  - | ConsumeListLenIndef (ST s (DecodeAction s a))
  - | ConsumeMapLenIndef (ST s (DecodeAction s a))
  - | ConsumeNull (ST s (DecodeAction s a))
  - | ConsumeListLenOrIndef (Int# -> ST s (DecodeAction s a))
  - | ConsumeMapLenOrIndef (Int# -> ST s (DecodeAction s a))
  - | ConsumeBreakOr (Bool -> ST s (DecodeAction s a))
  - | PeekTokenType (TokenType -> ST s (DecodeAction s a))
  - | PeekAvailable (Int# -> ST s (DecodeAction s a))
  - | PeekByteOffset (Int# -> ST s (DecodeAction s a))
  - | ConsumeWordCanonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord8Canonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord16Canonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeWord32Canonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeNegWordCanonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeIntCanonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt8Canonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt16Canonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeInt32Canonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeListLenCanonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeMapLenCanonical (Int# -> ST s (DecodeAction s a))
  - | ConsumeTagCanonical (Word# -> ST s (DecodeAction s a))
  - | ConsumeIntegerCanonical (Integer -> ST s (DecodeAction s a))
  - | ConsumeFloat16Canonical (Float# -> ST s (DecodeAction s a))
  - | ConsumeFloatCanonical (Float# -> ST s (DecodeAction s a))
  - | ConsumeDoubleCanonical (Double# -> ST s (DecodeAction s a))
  - | ConsumeBytesCanonical (ByteString -> ST s (DecodeAction s a))
  - | ConsumeByteArrayCanonical (ByteArray -> ST s (DecodeAction s a))
  - | ConsumeStringCanonical (Text -> ST s (DecodeAction s a))
  - | ConsumeUtf8ByteArrayCanonical (ByteArray -> ST s (DecodeAction s a))
  - | ConsumeSimpleCanonical (Word# -> ST s (DecodeAction s a))
  - | Fail String
  - | Done a
- liftST :: ST s a -> Decoder s a
- getDecodeAction :: Decoder s a -> ST s (DecodeAction s a)
- decodeWord :: Decoder s Word
- decodeWord8 :: Decoder s Word8
- decodeWord16 :: Decoder s Word16
- decodeWord32 :: Decoder s Word32
- decodeWord64 :: Decoder s Word64
- decodeNegWord :: Decoder s Word
- decodeNegWord64 :: Decoder s Word64
- decodeInt :: Decoder s Int
- decodeInt8 :: Decoder s Int8
- decodeInt16 :: Decoder s Int16
- decodeInt32 :: Decoder s Int32
- decodeInt64 :: Decoder s Int64
- decodeInteger :: Decoder s Integer
- decodeFloat :: Decoder s Float
- decodeDouble :: Decoder s Double
- decodeBytes :: Decoder s ByteString
- decodeBytesIndef :: Decoder s ()
- decodeByteArray :: Decoder s ByteArray
- decodeString :: Decoder s Text
- decodeStringIndef :: Decoder s ()
- decodeUtf8ByteArray :: Decoder s ByteArray
- decodeListLen :: Decoder s Int
- decodeListLenIndef :: Decoder s ()
- decodeMapLen :: Decoder s Int
- decodeMapLenIndef :: Decoder s ()
- decodeTag :: Decoder s Word
- decodeTag64 :: Decoder s Word64
- decodeBool :: Decoder s Bool
- decodeNull :: Decoder s ()
- decodeSimple :: Decoder s Word8
- decodeWordOf :: Word -> Decoder s ()
- decodeListLenOf :: Int -> Decoder s ()
- decodeListLenOrIndef :: Decoder s (Maybe Int)
- decodeMapLenOrIndef :: Decoder s (Maybe Int)
- decodeBreakOr :: Decoder s Bool
- peekTokenType :: Decoder s TokenType
- data TokenType
  - = TypeUInt
  - | TypeUInt64
  - | TypeNInt
  - | TypeNInt64
  - | TypeInteger
  - | TypeFloat16
  - | TypeFloat32
  - | TypeFloat64
  - | TypeBytes
  - | TypeBytesIndef
  - | TypeString
  - | TypeStringIndef
  - | TypeListLen
  - | TypeListLen64
  - | TypeListLenIndef
  - | TypeMapLen
  - | TypeMapLen64
  - | TypeMapLenIndef
  - | TypeTag
  - | TypeTag64
  - | TypeBool
  - | TypeNull
  - | TypeSimple
  - | TypeBreak
  - | TypeInvalid
- peekAvailable :: Decoder s Int
- type ByteOffset = Int64
- peekByteOffset :: Decoder s ByteOffset
- decodeWithByteSpan :: Decoder s a -> Decoder s (a, ByteOffset, ByteOffset)
- decodeWordCanonical :: Decoder s Word
- decodeWord8Canonical :: Decoder s Word8
- decodeWord16Canonical :: Decoder s Word16
- decodeWord32Canonical :: Decoder s Word32
- decodeWord64Canonical :: Decoder s Word64
- decodeNegWordCanonical :: Decoder s Word
- decodeNegWord64Canonical :: Decoder s Word64
- decodeIntCanonical :: Decoder s Int
- decodeInt8Canonical :: Decoder s Int8
- decodeInt16Canonical :: Decoder s Int16
- decodeInt32Canonical :: Decoder s Int32
- decodeInt64Canonical :: Decoder s Int64
- decodeBytesCanonical :: Decoder s ByteString
- decodeByteArrayCanonical :: Decoder s ByteArray
- decodeStringCanonical :: Decoder s Text
- decodeUtf8ByteArrayCanonical :: Decoder s ByteArray
- decodeListLenCanonical :: Decoder s Int
- decodeMapLenCanonical :: Decoder s Int
- decodeTagCanonical :: Decoder s Word
- decodeTag64Canonical :: Decoder s Word64
- decodeIntegerCanonical :: Decoder s Integer
- decodeFloat16Canonical :: Decoder s Float
- decodeFloatCanonical :: Decoder s Float
- decodeDoubleCanonical :: Decoder s Double
- decodeSimpleCanonical :: Decoder s Word8
- decodeWordCanonicalOf :: Word -> Decoder s ()
- decodeListLenCanonicalOf :: Int -> Decoder s ()
- decodeSequenceLenIndef :: (r -> a -> r) -> r -> (r -> r') -> Decoder s a -> Decoder s r'
- decodeSequenceLenN :: (r -> a -> r) -> r -> (r -> r') -> Int -> Decoder s a -> Decoder s r'

# Decode primitive operations

data Decoder s a #

A continuation-based decoder, used for decoding values that were previously encoded using the Codec.CBOR.Encoding module. As `Decoder` has a `Monad` instance, you can easily write `Decoder`s monadically for building your deserialisation logic.

Since: 0.2.0.0

#### Instances

Instances details

Applicative (Decoder s) # | Since: 0.2.0.0
Instance details Defined in Codec.CBOR.Decoding Methods pure :: a -> Decoder s a # (<*>) :: Decoder s (a -> b) -> Decoder s a -> Decoder s b # liftA2 :: (a -> b -> c) -> Decoder s a -> Decoder s b -> Decoder s c # (*>) :: Decoder s a -> Decoder s b -> Decoder s b # (<*) :: Decoder s a -> Decoder s b -> Decoder s a #
Functor (Decoder s) # | Since: 0.2.0.0
Instance details Defined in Codec.CBOR.Decoding Methods fmap :: (a -> b) -> Decoder s a -> Decoder s b # (<$) :: a -> Decoder s b -> Decoder s a #
Monad (Decoder s) # | Since: 0.2.0.0
Instance details Defined in Codec.CBOR.Decoding Methods (>>=) :: Decoder s a -> (a -> Decoder s b) -> Decoder s b # (>>) :: Decoder s a -> Decoder s b -> Decoder s b # return :: a -> Decoder s a #
MonadFail (Decoder s) # | Since: 0.2.0.0
Instance details Defined in Codec.CBOR.Decoding Methods fail :: String -> Decoder s a #

data DecodeAction s a #

An action, representing a step for a decoder to taken and a continuation to invoke with the expected value.

Since: 0.2.0.0

Constructors

ConsumeWord (Word# -> ST s (DecodeAction s a)) |
ConsumeWord8 (Word# -> ST s (DecodeAction s a)) |
ConsumeWord16 (Word# -> ST s (DecodeAction s a)) |
ConsumeWord32 (Word# -> ST s (DecodeAction s a)) |
ConsumeNegWord (Word# -> ST s (DecodeAction s a)) |
ConsumeInt (Int# -> ST s (DecodeAction s a)) |
ConsumeInt8 (Int# -> ST s (DecodeAction s a)) |
ConsumeInt16 (Int# -> ST s (DecodeAction s a)) |
ConsumeInt32 (Int# -> ST s (DecodeAction s a)) |
ConsumeListLen (Int# -> ST s (DecodeAction s a)) |
ConsumeMapLen (Int# -> ST s (DecodeAction s a)) |
ConsumeTag (Word# -> ST s (DecodeAction s a)) |
ConsumeInteger (Integer -> ST s (DecodeAction s a)) |
ConsumeFloat (Float# -> ST s (DecodeAction s a)) |
ConsumeDouble (Double# -> ST s (DecodeAction s a)) |
ConsumeBytes (ByteString -> ST s (DecodeAction s a)) |
ConsumeByteArray (ByteArray -> ST s (DecodeAction s a)) |
ConsumeString (Text -> ST s (DecodeAction s a)) |
ConsumeUtf8ByteArray (ByteArray -> ST s (DecodeAction s a)) |
ConsumeBool (Bool -> ST s (DecodeAction s a)) |
ConsumeSimple (Word# -> ST s (DecodeAction s a)) |
ConsumeBytesIndef (ST s (DecodeAction s a)) |
ConsumeStringIndef (ST s (DecodeAction s a)) |
ConsumeListLenIndef (ST s (DecodeAction s a)) |
ConsumeMapLenIndef (ST s (DecodeAction s a)) |
ConsumeNull (ST s (DecodeAction s a)) |
ConsumeListLenOrIndef (Int# -> ST s (DecodeAction s a)) |
ConsumeMapLenOrIndef (Int# -> ST s (DecodeAction s a)) |
ConsumeBreakOr (Bool -> ST s (DecodeAction s a)) |
PeekTokenType (TokenType -> ST s (DecodeAction s a)) |
PeekAvailable (Int# -> ST s (DecodeAction s a)) |
PeekByteOffset (Int# -> ST s (DecodeAction s a)) |
ConsumeWordCanonical (Word# -> ST s (DecodeAction s a)) |
ConsumeWord8Canonical (Word# -> ST s (DecodeAction s a)) |
ConsumeWord16Canonical (Word# -> ST s (DecodeAction s a)) |
ConsumeWord32Canonical (Word# -> ST s (DecodeAction s a)) |
ConsumeNegWordCanonical (Word# -> ST s (DecodeAction s a)) |
ConsumeIntCanonical (Int# -> ST s (DecodeAction s a)) |
ConsumeInt8Canonical (Int# -> ST s (DecodeAction s a)) |
ConsumeInt16Canonical (Int# -> ST s (DecodeAction s a)) |
ConsumeInt32Canonical (Int# -> ST s (DecodeAction s a)) |
ConsumeListLenCanonical (Int# -> ST s (DecodeAction s a)) |
ConsumeMapLenCanonical (Int# -> ST s (DecodeAction s a)) |
ConsumeTagCanonical (Word# -> ST s (DecodeAction s a)) |
ConsumeIntegerCanonical (Integer -> ST s (DecodeAction s a)) |
ConsumeFloat16Canonical (Float# -> ST s (DecodeAction s a)) |
ConsumeFloatCanonical (Float# -> ST s (DecodeAction s a)) |
ConsumeDoubleCanonical (Double# -> ST s (DecodeAction s a)) |
ConsumeBytesCanonical (ByteString -> ST s (DecodeAction s a)) |
ConsumeByteArrayCanonical (ByteArray -> ST s (DecodeAction s a)) |
ConsumeStringCanonical (Text -> ST s (DecodeAction s a)) |
ConsumeUtf8ByteArrayCanonical (ByteArray -> ST s (DecodeAction s a)) |
ConsumeSimpleCanonical (Word# -> ST s (DecodeAction s a)) |
Fail String |
Done a |

liftST :: ST s a -> Decoder s a #

Lift an `ST` action into a `Decoder`. Useful for, e.g., leveraging in-place mutation to efficiently build a deserialised value.

Since: 0.2.0.0

getDecodeAction :: Decoder s a -> ST s (DecodeAction s a) #

Given a `Decoder`, give us the `DecodeAction`

Since: 0.2.0.0

## Read input tokens

decodeWord :: Decoder s Word #

Decode a `Word`.

Since: 0.2.0.0

decodeWord8 :: Decoder s Word8 #

Decode a `Word8`.

Since: 0.2.0.0

decodeWord16 :: Decoder s Word16 #

Decode a `Word16`.

Since: 0.2.0.0

decodeWord32 :: Decoder s Word32 #

Decode a `Word32`.

Since: 0.2.0.0

decodeWord64 :: Decoder s Word64 #

Decode a `Word64`.

Since: 0.2.0.0

decodeNegWord :: Decoder s Word #

Decode a negative `Word`.

Since: 0.2.0.0

decodeNegWord64 :: Decoder s Word64 #

Decode a negative `Word64`.

Since: 0.2.0.0

decodeInt :: Decoder s Int #

Decode an `Int`.

Since: 0.2.0.0

decodeInt8 :: Decoder s Int8 #

Decode an `Int8`.

Since: 0.2.0.0

decodeInt16 :: Decoder s Int16 #

Decode an `Int16`.

Since: 0.2.0.0

decodeInt32 :: Decoder s Int32 #

Decode an `Int32`.

Since: 0.2.0.0

decodeInt64 :: Decoder s Int64 #

Decode an `Int64`.

Since: 0.2.0.0

decodeInteger :: Decoder s Integer #

Decode an `Integer`.

Since: 0.2.0.0

decodeFloat :: Decoder s Float #

Decode a `Float`.

Since: 0.2.0.0

decodeDouble :: Decoder s Double #

Decode a `Double`.

Since: 0.2.0.0

decodeBytes :: Decoder s ByteString #

Decode a string of bytes as a `ByteString`.

Since: 0.2.0.0

decodeBytesIndef :: Decoder s () #

Decode a token marking the beginning of an indefinite length set of bytes.

Since: 0.2.0.0

decodeByteArray :: Decoder s ByteArray #

Decode a string of bytes as a `ByteArray`.

Also note that this will eagerly copy the content out of the input to ensure that the input does not leak in the event that the `ByteArray` is live but not forced.

Since: 0.2.0.0

decodeString :: Decoder s Text #

Decode a textual string as a piece of `Text`.

Since: 0.2.0.0

decodeStringIndef :: Decoder s () #

Decode a token marking the beginning of an indefinite length string.

Since: 0.2.0.0

decodeUtf8ByteArray :: Decoder s ByteArray #

Decode a textual string as UTF-8 encoded `ByteArray`. Note that the result is not validated to be well-formed UTF-8.

Also note that this will eagerly copy the content out of the input to ensure that the input does not leak in the event that the `ByteArray` is live but not forced.

Since: 0.2.0.0

decodeListLen :: Decoder s Int #

Decode the length of a list.

Since: 0.2.0.0

decodeListLenIndef :: Decoder s () #

Decode a token marking the beginning of a list of indefinite length.

Since: 0.2.0.0

decodeMapLen :: Decoder s Int #

Decode the length of a map.

Since: 0.2.0.0

decodeMapLenIndef :: Decoder s () #

Decode a token marking the beginning of a map of indefinite length.

Since: 0.2.0.0

decodeTag :: Decoder s Word #

Decode an arbitrary tag and return it as a `Word`.

Since: 0.2.0.0

decodeTag64 :: Decoder s Word64 #

Decode an arbitrary 64-bit tag and return it as a `Word64`.

Since: 0.2.0.0

decodeBool :: Decoder s Bool #

Decode a bool.

Since: 0.2.0.0

decodeNull :: Decoder s () #

Decode a nullary value, and return a unit value.

Since: 0.2.0.0

decodeSimple :: Decoder s Word8 #

Decode a `simple` CBOR value and give back a `Word8`. You probably don't ever need to use this.

Since: 0.2.0.0

## Specialised Read input token operations

decodeWordOf #

Arguments

:: Word | Expected value of the decoded word
-> Decoder s () |

Attempt to decode a word with `decodeWord`, and ensure the word is exactly as expected, or fail.

Since: 0.2.0.0

decodeListLenOf :: Int -> Decoder s () #

Attempt to decode a list length using `decodeListLen`, and ensure it is exactly the specified length, or fail.

Since: 0.2.0.0

## Branching operations

decodeListLenOrIndef :: Decoder s (Maybe Int) #

Attempt to decode a token for the length of a finite, known list, or an indefinite list. If `Nothing` is returned, then an indefinite length list occurs afterwords. If ``Just` x` is returned, then a list of length `x` is encoded.

Since: 0.2.0.0

decodeMapLenOrIndef :: Decoder s (Maybe Int) #

Attempt to decode a token for the length of a finite, known map, or an indefinite map. If `Nothing` is returned, then an indefinite length map occurs afterwords. If ``Just` x` is returned, then a map of length `x` is encoded.

Since: 0.2.0.0

decodeBreakOr :: Decoder s Bool #

Attempt to decode a `Break` token, and if that was successful, return `True`. If the token was of any other type, return `False`.

Since: 0.2.0.0

## Inspecting the token type

peekTokenType :: Decoder s TokenType #

Peek at the current token we're about to decode, and return a `TokenType` specifying what it is.

Since: 0.2.0.0

data TokenType #

The type of a token, which a decoder can ask for at an arbitrary time.

Since: 0.2.0.0

Constructors

TypeUInt |
TypeUInt64 |
TypeNInt |
TypeNInt64 |
TypeInteger |
TypeFloat16 |
TypeFloat32 |
TypeFloat64 |
TypeBytes |
TypeBytesIndef |
TypeString |
TypeStringIndef |
TypeListLen |
TypeListLen64 |
TypeListLenIndef |
TypeMapLen |
TypeMapLen64 |
TypeMapLenIndef |
TypeTag |
TypeTag64 |
TypeBool |
TypeNull |
TypeSimple |
TypeBreak |
TypeInvalid |

#### Instances

Instances details

Bounded TokenType # |
Instance details Defined in Codec.CBOR.Decoding Methods minBound :: TokenType # maxBound :: TokenType #
Enum TokenType # |
Instance details Defined in Codec.CBOR.Decoding Methods succ :: TokenType -> TokenType # pred :: TokenType -> TokenType # toEnum :: Int -> TokenType # fromEnum :: TokenType -> Int # enumFrom :: TokenType -> [TokenType] # enumFromThen :: TokenType -> TokenType -> [TokenType] # enumFromTo :: TokenType -> TokenType -> [TokenType] # enumFromThenTo :: TokenType -> TokenType -> TokenType -> [TokenType] #
Show TokenType # |
Instance details Defined in Codec.CBOR.Decoding Methods showsPrec :: Int -> TokenType -> ShowS # show :: TokenType -> String # showList :: [TokenType] -> ShowS #
Eq TokenType # |
Instance details Defined in Codec.CBOR.Decoding Methods (==) :: TokenType -> TokenType -> Bool # (/=) :: TokenType -> TokenType -> Bool #
Ord TokenType # |
Instance details Defined in Codec.CBOR.Decoding Methods compare :: TokenType -> TokenType -> Ordering # (<) :: TokenType -> TokenType -> Bool # (<=) :: TokenType -> TokenType -> Bool # (>) :: TokenType -> TokenType -> Bool # (>=) :: TokenType -> TokenType -> Bool # max :: TokenType -> TokenType -> TokenType # min :: TokenType -> TokenType -> TokenType #

## Special operations

peekAvailable :: Decoder s Int #

Peek and return the length of the current buffer that we're running our decoder on.

Since: 0.2.0.0

type ByteOffset = Int64 #

A 0-based offset within the overall byte sequence that makes up the input to the `Decoder`.

This is an `Int64` since `Decoder` is incremental and can decode more data than fits in memory at once. This is also compatible with the result type of `length`.

peekByteOffset :: Decoder s ByteOffset #

Get the current `ByteOffset` in the input byte sequence of the `Decoder`.

The `Decoder` does not provide any facility to get at the input data directly (since that is tricky with an incremental decoder). The next best is this primitive which can be used to keep track of the offset within the input bytes that makes up the encoded form of a term.

By keeping track of the byte offsets before and after decoding a subterm (a pattern captured by `decodeWithByteSpan`) and if the overall input data is retained then this is enables later retrieving the span of bytes for the subterm.

Since: 0.2.2.0

decodeWithByteSpan :: Decoder s a -> Decoder s (a, ByteOffset, ByteOffset) #

This captures the pattern of getting the byte offsets before and after decoding a subterm.

    !before <- peekByteOffset
    x <- decode
    !after  <- peekByteOffset

## Canonical CBOR

https://tools.ietf.org/html/rfc7049#section-3.9

In general in CBOR there can be multiple representations for the same value, for example the integer `0` can be represented in 8, 16, 32 or 64 bits. This library always encoded values in the shortest representation but on decoding allows any valid encoding. For some applications it is useful or important to only decode the canonical encoding. The decoder primitives here are to allow applications to implement canonical decoding.

It is important to note that achieving a canonical representation is not simply about using these primitives. For example consider a typical CBOR encoding of a Haskell `Set` data type. This will be encoded as a CBOR list of the set elements. A typical implementation might be:

    encodeSet = encodeList . Set.toList
    decodeSet = fmap Set.fromList . decodeList

This does not enforce a canonical encoding. The decoder above will allow set elements in any order. The use of `Set.fromList` forgets the order. To enforce that the decoder only accepts the canonical encoding it will have to check that the elements in the list are strictly increasing. Similar issues arise in many other data types, wherever there is redundancy in the external representation.

The decoder primitives in this section are not much more expensive than their normal counterparts. If checking the canonical encoding property is critical then a technique that is more expensive but easier to implement and test is to decode normally, re-encode and check the serialised bytes are the same.

decodeWordCanonical :: Decoder s Word #

Decode canonical representation of a `Word`.

Since: 0.2.0.0

decodeWord8Canonical :: Decoder s Word8 #

Decode canonical representation of a `Word8`.

Since: 0.2.0.0

decodeWord16Canonical :: Decoder s Word16 #

Decode canonical representation of a `Word16`.

Since: 0.2.0.0

decodeWord32Canonical :: Decoder s Word32 #

Decode canonical representation of a `Word32`.

Since: 0.2.0.0

decodeWord64Canonical :: Decoder s Word64 #

Decode canonical representation of a `Word64`.

Since: 0.2.0.0

decodeNegWordCanonical :: Decoder s Word #

Decode canonical representation of a negative `Word`.

Since: 0.2.0.0

decodeNegWord64Canonical :: Decoder s Word64 #

Decode canonical representation of a negative `Word64`.

Since: 0.2.0.0

decodeIntCanonical :: Decoder s Int #

Decode canonical representation of an `Int`.

Since: 0.2.0.0

decodeInt8Canonical :: Decoder s Int8 #

Decode canonical representation of an `Int8`.

Since: 0.2.0.0

decodeInt16Canonical :: Decoder s Int16 #

Decode canonical representation of an `Int16`.

Since: 0.2.0.0

decodeInt32Canonical :: Decoder s Int32 #

Decode canonical representation of an `Int32`.

Since: 0.2.0.0

decodeInt64Canonical :: Decoder s Int64 #

Decode canonical representation of an `Int64`.

Since: 0.2.0.0

decodeBytesCanonical :: Decoder s ByteString #

Decode canonical representation of a string of bytes as a `ByteString`.

Since: 0.2.1.0

decodeByteArrayCanonical :: Decoder s ByteArray #

Decode canonical representation of a string of bytes as a `ByteArray`.

Also note that this will eagerly copy the content out of the input to ensure that the input does not leak in the event that the `ByteArray` is live but not forced.

Since: 0.2.1.0

decodeStringCanonical :: Decoder s Text #

Decode canonical representation of a textual string as a piece of `Text`.

Since: 0.2.1.0

decodeUtf8ByteArrayCanonical :: Decoder s ByteArray #

Decode canonical representation of a textual string as UTF-8 encoded `ByteArray`. Note that the result is not validated to be well-formed UTF-8.

Also note that this will eagerly copy the content out of the input to ensure that the input does not leak in the event that the `ByteArray` is live but not forced.

Since: 0.2.1.0

decodeListLenCanonical :: Decoder s Int #

Decode canonical representation of the length of a list.

Since: 0.2.0.0

decodeMapLenCanonical :: Decoder s Int #

Decode canonical representation of the length of a map.

Since: 0.2.0.0

decodeTagCanonical :: Decoder s Word #

Decode canonical representation of an arbitrary tag and return it as a `Word`.

Since: 0.2.0.0

decodeTag64Canonical :: Decoder s Word64 #

Decode canonical representation of an arbitrary 64-bit tag and return it as a `Word64`.

Since: 0.2.0.0

decodeIntegerCanonical :: Decoder s Integer #

Decode canonical representation of an `Integer`.

Since: 0.2.0.0

decodeFloat16Canonical :: Decoder s Float #

Decode canonical representation of a half-precision `Float`.

Since: 0.2.0.0

decodeFloatCanonical :: Decoder s Float #

Decode canonical representation of a `Float`.

Since: 0.2.0.0

decodeDoubleCanonical :: Decoder s Double #

Decode canonical representation of a `Double`.

Since: 0.2.0.0

decodeSimpleCanonical :: Decoder s Word8 #

Decode canonical representation of a `simple` CBOR value and give back a `Word8`. You probably don't ever need to use this.

Since: 0.2.0.0

decodeWordCanonicalOf #

Arguments

:: Word | Expected value of the decoded word
-> Decoder s () |

Attempt to decode canonical representation of a word with `decodeWordCanonical`, and ensure the word is exactly as expected, or fail.

Since: 0.2.0.0

decodeListLenCanonicalOf :: Int -> Decoder s () #

Attempt to decode canonical representation of a list length using `decodeListLenCanonical`, and ensure it is exactly the specified length, or fail.

Since: 0.2.0.0

# Sequence operations

decodeSequenceLenIndef :: (r -> a -> r) -> r -> (r -> r') -> Decoder s a -> Decoder s r' #

Decode an indefinite sequence length.

Since: 0.2.0.0

decodeSequenceLenN :: (r -> a -> r) -> r -> (r -> r') -> Int -> Decoder s a -> Decoder s r' #

Decode a sequence length.

Since: 0.2.0.0