vector-0.7.0.1: Efficient Arrays

Portabilitynon-portable
Stabilityexperimental
MaintainerRoman Leshchinskiy <rl@cse.unsw.edu.au>

Data.Vector.Storable.Mutable

Contents

Description

Mutable vectors based on Storable.

Synopsis

Mutable vectors of Storable types

data MVector s a Source

Mutable Storable-based vectors

Constructors

MVector !(Ptr a) !Int !(ForeignPtr a) 

class Storable a

The member functions of this class facilitate writing values of primitive types to raw memory (which may have been allocated with the above mentioned routines) and reading values from blocks of raw memory. The class, furthermore, includes support for computing the storage requirements and alignment restrictions of storable types.

Memory addresses are represented as values of type Ptr a, for some a which is an instance of class Storable. The type argument to Ptr helps provide some valuable type safety in FFI code (you can't mix pointers of different types without an explicit cast), while helping the Haskell type system figure out which marshalling method is needed for a given pointer.

All marshalling between Haskell and a foreign language ultimately boils down to translating Haskell data structures into the binary representation of a corresponding data structure of the foreign language and vice versa. To code this marshalling in Haskell, it is necessary to manipulate primitive data types stored in unstructured memory blocks. The class Storable facilitates this manipulation on all types for which it is instantiated, which are the standard basic types of Haskell, the fixed size Int types (Int8, Int16, Int32, Int64), the fixed size Word types (Word8, Word16, Word32, Word64), StablePtr, all types from Foreign.C.Types, as well as Ptr.

Minimal complete definition: sizeOf, alignment, one of peek, peekElemOff and peekByteOff, and one of poke, pokeElemOff and pokeByteOff.

Accessors

Length information

length :: Storable a => MVector s a -> IntSource

Length of the mutable vector.

null :: Storable a => MVector s a -> BoolSource

Check whether the vector is empty

Extracting subvectors

slice :: Storable a => Int -> Int -> MVector s a -> MVector s aSource

Yield a part of the mutable vector without copying it.

init :: Storable a => MVector s a -> MVector s aSource

tail :: Storable a => MVector s a -> MVector s aSource

take :: Storable a => Int -> MVector s a -> MVector s aSource

drop :: Storable a => Int -> MVector s a -> MVector s aSource

unsafeSliceSource

Arguments

:: Storable a 
=> Int

starting index

-> Int

length of the slice

-> MVector s a 
-> MVector s a 

Yield a part of the mutable vector without copying it. No bounds checks are performed.

Overlapping

Construction

Initialisation

new :: (PrimMonad m, Storable a) => Int -> m (MVector (PrimState m) a)Source

Create a mutable vector of the given length.

unsafeNew :: (PrimMonad m, Storable a) => Int -> m (MVector (PrimState m) a)Source

Create a mutable vector of the given length. The length is not checked.

replicate :: (PrimMonad m, Storable a) => Int -> a -> m (MVector (PrimState m) a)Source

Create a mutable vector of the given length (0 if the length is negative) and fill it with an initial value.

clone :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> m (MVector (PrimState m) a)Source

Create a copy of a mutable vector.

Growing

grow :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> m (MVector (PrimState m) a)Source

Grow a vector by the given number of elements. The number must be positive.

unsafeGrow :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> m (MVector (PrimState m) a)Source

Grow a vector by the given number of elements. The number must be positive but this is not checked.

Restricting memory usage

clear :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> m ()Source

Reset all elements of the vector to some undefined value, clearing all references to external objects. This is usually a noop for unboxed vectors.

Accessing individual elements

read :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> m aSource

Yield the element at the given position.

write :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> a -> m ()Source

Replace the element at the given position.

swap :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> Int -> m ()Source

Swap the elements at the given positions.

unsafeRead :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> m aSource

Yield the element at the given position. No bounds checks are performed.

unsafeWrite :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> a -> m ()Source

Replace the element at the given position. No bounds checks are performed.

unsafeSwap :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> Int -> Int -> m ()Source

Swap the elements at the given positions. No bounds checks are performed.

Modifying vectors

Filling and copying

set :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> a -> m ()Source

Set all elements of the vector to the given value.

copy :: (PrimMonad m, Storable a) => MVector (PrimState m) a -> MVector (PrimState m) a -> m ()Source

Copy a vector. The two vectors must have the same length and may not overlap.

unsafeCopySource

Arguments

:: (PrimMonad m, Storable a) 
=> MVector (PrimState m) a

target

-> MVector (PrimState m) a

source

-> m () 

Copy a vector. The two vectors must have the same length and may not overlap. This is not checked.

Raw pointers

unsafeFromForeignPtrSource

Arguments

:: Storable a 
=> ForeignPtr a

pointer

-> Int

offset

-> Int

length

-> MVector s a 

Create a mutable vector from a ForeignPtr with an offset and a length. Modifying data through the ForeignPtr afterwards is unsafe if the vector could have been frozen before the modification.

unsafeToForeignPtr :: Storable a => MVector s a -> (ForeignPtr a, Int, Int)Source

Yield the underlying ForeignPtr together with the offset to the data and its length. Modifying the data through the ForeignPtr is unsafe if the vector could have frozen before the modification.

unsafeWith :: Storable a => IOVector a -> (Ptr a -> IO b) -> IO bSource

Pass a pointer to the vector's data to the IO action. Modifying data through the pointer is unsafe if the vector could have been frozen before the modification.

Deprecated operations

newWith :: (PrimMonad m, Storable a) => Int -> a -> m (MVector (PrimState m) a)Source

DEPRECATED Use replicate instead

unsafeNewWith :: (PrimMonad m, Storable a) => Int -> a -> m (MVector (PrimState m) a)Source

DEPRECATED Use replicate instead