Safe Haskell	Safe-Inferred
Language	GHC2021

Binrep.Type.Magic

Description

Magic numbers (also just magic): short constant bytestrings usually found at the top of a file, often used as an early sanity check.

There are two main flavors of magics:

byte magics e.g. Zstandard: 28 B5 2F FD
printable magics e.g. Ogg: 4F 67 67 53 -> OggS (in ASCII)

For byte magics, use type-level Natural lists. For printable magics, use Symbols (type-level strings).

Synopsis

data Magic (a :: k) = Magic
class Magical (a :: k) where
- type MagicBytes a :: [Natural]
type family Length (a :: [k]) :: Natural where ...

Documentation

data Magic (a :: k) Source #

A singleton data type representing a "magic number" via a phantom type.

The phantom type variable unambiguously defines a constant bytestring. A handful of types are supported for using magics conveniently, e.g. for pure ASCII magics, you may use a Symbol type-level string.

Constructors

Magic

Instances

Instances details

IsCBLen (Magic a :: Type) Source #	The byte length of a magic is known at compile time.
Instance details Defined in Binrep.Type.Magic Associated Types type CBLen (Magic a) :: Natural Source #
(Typeable a, Typeable k) => Data (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Magic a -> c (Magic a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Magic a) # toConstr :: Magic a -> Constr # dataTypeOf :: Magic a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Magic a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Magic a)) # gmapT :: (forall b. Data b => b -> b) -> Magic a -> Magic a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Magic a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Magic a -> r # gmapQ :: (forall d. Data d => d -> u) -> Magic a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Magic a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Magic a -> m (Magic a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Magic a -> m (Magic a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Magic a -> m (Magic a) #
Generic (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Associated Types type Rep (Magic a) :: Type -> Type # Methods from :: Magic a -> Rep (Magic a) x # to :: Rep (Magic a) x -> Magic a #
Show (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods showsPrec :: Int -> Magic a -> ShowS # show :: Magic a -> String # showList :: [Magic a] -> ShowS #
KnownNat (Length (MagicBytes a)) => BLen (Magic a) Source #	The byte length of a magic is obtained via reifying.
Instance details Defined in Binrep.Type.Magic Methods blen :: Magic a -> Int Source #
(bs ~ MagicBytes a, ParseReifyBytesW64 bs, ReifyBytesW64 bs, KnownNat (Length bs)) => Get (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods get :: Getter (Magic a) Source #
(bs ~ MagicBytes a, ParseReifyBytesW64 bs, ReifyBytesW64 bs, KnownNat (Length bs)) => GetC (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods getC :: GetterC (Magic a) Source #
(bs ~ MagicBytes a, ReifyBytesW64 bs, KnownNat (Length bs)) => Put (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods put :: Magic a -> Putter Source #
(bs ~ MagicBytes a, ReifyBytesW64 bs) => PutC (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods putC :: Magic a -> PutterC Source #
Eq (Magic a) Source #
Instance details Defined in Binrep.Type.Magic Methods (==) :: Magic a -> Magic a -> Bool # (/=) :: Magic a -> Magic a -> Bool #
Strengthen (Magic a) Source #	Strengthen the unit to some `Magic a`.
Instance details Defined in Binrep.Type.Magic Methods strengthen :: Weak (Magic a) -> Result (Magic a) #
Weaken (Magic a) Source #	Weaken a `Magic a` to the unit.
Instance details Defined in Binrep.Type.Magic Associated Types type Weak (Magic a) # Methods weaken :: Magic a -> Weak (Magic a) #
type CBLen (Magic a :: Type) Source #
Instance details Defined in Binrep.Type.Magic type CBLen (Magic a :: Type) = Length (MagicBytes a)
type Rep (Magic a) Source #
Instance details Defined in Binrep.Type.Magic type Rep (Magic a) = D1 ('MetaData "Magic" "Binrep.Type.Magic" "binrep-0.8.0-inplace" 'False) (C1 ('MetaCons "Magic" 'PrefixI 'False) (U1 :: Type -> Type))
type Weak (Magic a) Source #
Instance details Defined in Binrep.Type.Magic type Weak (Magic a) = ()

class Magical (a :: k) Source #

Types which define a magic value.

Associated Types

type MagicBytes a :: [Natural] Source #

How to turn the type into a list of bytes.

Instances

Instances details

Magical (sym :: Symbol) Source #	Type-level symbols are converted to UTF-8.
Instance details Defined in Binrep.Type.Magic Associated Types type MagicBytes sym :: [Natural] Source #
Magical (ns :: [Natural]) Source #	Type-level naturals go as-is. (Make sure you don't go over 255, though!)
Instance details Defined in Binrep.Type.Magic Associated Types type MagicBytes ns :: [Natural] Source #

type family Length (a :: [k]) :: Natural where ... Source #

The length of a type-level list.

Equations

Length '[] = 0
Length (a ': as) = 1 + Length as