Safe Haskell	None
Language	Haskell2010

Capnp.Pointer

Description

This module provides support for parsing and serializing capnproto pointers. This is a low-level module; most users will not need to call it directly.

Synopsis

data Ptr
- = StructPtr !Int32 !Word16 !Word16
- | ListPtr !Int32 !EltSpec
- | FarPtr !Bool !Word32 !Word32
- | CapPtr !Word32
data ElementSize
- = Sz0
- | Sz1
- | Sz8
- | Sz16
- | Sz32
- | Sz64
- | SzPtr
data EltSpec
- = EltNormal !ElementSize !Word32
- | EltComposite !Int32
parsePtr :: Word64 -> Maybe Ptr
parsePtr' :: Word64 -> Ptr
serializePtr :: Maybe Ptr -> Word64
serializePtr' :: Ptr -> Word64
parseEltSpec :: Word64 -> EltSpec
serializeEltSpec :: EltSpec -> Word64

Documentation

data Ptr Source #

A Ptr represents the information in a capnproto pointer.

Constructors

StructPtr !Int32 !Word16 !Word16	`StructPtr off dataSz ptrSz` is a pointer to a struct at offset `off` in words from the end of the pointer, with a data section of size `dataSz` words, and a pointer section of size `ptrSz` words. Note that the value `StructPtr 0 0 0` is illegal, since its encoding is reserved for the "null" pointer.
ListPtr !Int32 !EltSpec	`ListPtr off eltSpec` is a pointer to a list starting at offset `off` in words from the end of the pointer. `eltSpec` encodes the C and D fields in the encoding spec; see `EltSpec` for details
FarPtr !Bool !Word32 !Word32	`FarPtr twoWords off segment` is a far pointer, whose landing pad is: two words iff `twoWords`, `off` words from the start of the target segment, and in segment id `segment`.
CapPtr !Word32	`CapPtr id` is a pointer to the capability with the id `id`.

Instances

Instances details

Eq Ptr Source #
Instance details Defined in Capnp.Pointer Methods (==) :: Ptr -> Ptr -> Bool # (/=) :: Ptr -> Ptr -> Bool #
Show Ptr Source #
Instance details Defined in Capnp.Pointer Methods showsPrec :: Int -> Ptr -> ShowS # show :: Ptr -> String # showList :: [Ptr] -> ShowS #

data ElementSize Source #

The element size field in a list pointer.

Constructors

Sz0
Sz1
Sz8
Sz16
Sz32
Sz64
SzPtr

Instances

Instances details

Enum ElementSize Source #
Instance details Defined in Capnp.Pointer Methods succ :: ElementSize -> ElementSize # pred :: ElementSize -> ElementSize # toEnum :: Int -> ElementSize # fromEnum :: ElementSize -> Int # enumFrom :: ElementSize -> [ElementSize] # enumFromThen :: ElementSize -> ElementSize -> [ElementSize] # enumFromTo :: ElementSize -> ElementSize -> [ElementSize] # enumFromThenTo :: ElementSize -> ElementSize -> ElementSize -> [ElementSize] #
Eq ElementSize Source #
Instance details Defined in Capnp.Pointer Methods (==) :: ElementSize -> ElementSize -> Bool # (/=) :: ElementSize -> ElementSize -> Bool #
Show ElementSize Source #
Instance details Defined in Capnp.Pointer Methods showsPrec :: Int -> ElementSize -> ShowS # show :: ElementSize -> String # showList :: [ElementSize] -> ShowS #

data EltSpec Source #

A combination of the C and D fields in a list pointer, i.e. the element size, and either the number of elements in the list, or the total number of words in the list (if size is composite).

Constructors

EltNormal !ElementSize !Word32	`EltNormal size len` is a normal (non-composite) element type (C /= 7). `size` is the size of the elements, and `len` is the number of elements in the list.
EltComposite !Int32	`EltComposite len` is a composite element (C == 7). `len` is the length of the list in words.

Instances

Instances details

Eq EltSpec Source #
Instance details Defined in Capnp.Pointer Methods (==) :: EltSpec -> EltSpec -> Bool # (/=) :: EltSpec -> EltSpec -> Bool #
Show EltSpec Source #
Instance details Defined in Capnp.Pointer Methods showsPrec :: Int -> EltSpec -> ShowS # show :: EltSpec -> String # showList :: [EltSpec] -> ShowS #

parsePtr :: Word64 -> Maybe Ptr Source #

parsePtr word parses word as a capnproto pointer. A null pointer is parsed as Nothing.

parsePtr' :: Word64 -> Ptr Source #

parsePtr' word parses word as a capnproto pointer. It ignores nulls, returning them the same as (StructPtr 0 0 0).

serializePtr :: Maybe Ptr -> Word64 Source #

serializePtr ptr serializes the pointer as a Word64, translating Nothing to a null pointer.

This also changes the offset of zero-sized struct pointers to -1, to avoid them being interpreted as null.

serializePtr' :: Ptr -> Word64 Source #

serializePtr' ptr serializes the pointer as a Word64.

Unlike serializePtr, this results in a null pointer on the input (StructPtr 0 0 0), rather than adjusting the offset.

parseEltSpec :: Word64 -> EltSpec Source #

parseEltSpec word reads the EltSpec from word, which must be the encoding of a list pointer (this is not verified).

serializeEltSpec :: EltSpec -> Word64 Source #

serializeEltSpec eltSpec serializes eltSpec as a Word64. all bits which are not determined by the EltSpec are zero.