| Portability | non-portable (uses Data.Array.MArray) |
|---|---|
| Stability | experimental |
| Maintainer | libraries@haskell.org |
| Safe Haskell | None |
Data.Array.Unsafe
Contents
Description
Contains the various unsafe operations that can be performed on arrays.
- castSTUArray :: STUArray s ix a -> ST s (STUArray s ix b)
- castIOUArray :: IOUArray ix a -> IO (IOUArray ix b)
- unsafeFreeze :: (Ix i, MArray a e m, IArray b e) => a i e -> m (b i e)
- unsafeThaw :: (Ix i, IArray a e, MArray b e m) => a i e -> m (b i e)
- unsafeForeignPtrToStorableArray :: Ix i => ForeignPtr e -> (i, i) -> IO (StorableArray i e)
Unsafe operations
castSTUArray :: STUArray s ix a -> ST s (STUArray s ix b)Source
Casts an STUArray with one element type into one with a
different element type. All the elements of the resulting array
are undefined (unless you know what you're doing...).
castIOUArray :: IOUArray ix a -> IO (IOUArray ix b)Source
Casts an IOUArray with one element type into one with a
different element type. All the elements of the resulting array
are undefined (unless you know what you're doing...).
unsafeFreeze :: (Ix i, MArray a e m, IArray b e) => a i e -> m (b i e)Source
Converts an mutable array into an immutable array. The implementation may either simply cast the array from one type to the other without copying the array, or it may take a full copy of the array.
Note that because the array is possibly not copied, any subsequent modifications made to the mutable version of the array may be shared with the immutable version. It is safe to use, therefore, if the mutable version is never modified after the freeze operation.
The non-copying implementation is supported between certain pairs
of array types only; one constraint is that the array types must
have identical representations. In GHC, The following pairs of
array types have a non-copying O(1) implementation of
unsafeFreeze. Because the optimised versions are enabled by
specialisations, you will need to compile with optimisation (-O) to
get them.
unsafeThaw :: (Ix i, IArray a e, MArray b e m) => a i e -> m (b i e)Source
Converts an immutable array into a mutable array. The implementation may either simply cast the array from one type to the other without copying the array, or it may take a full copy of the array.
Note that because the array is possibly not copied, any subsequent modifications made to the mutable version of the array may be shared with the immutable version. It is only safe to use, therefore, if the immutable array is never referenced again in this thread, and there is no possibility that it can be also referenced in another thread. If you use an unsafeThawwriteunsafeFreeze sequence in a multi-threaded setting, then you must ensure that this sequence is atomic with respect to other threads, or a garbage collector crash may result (because the write may be writing to a frozen array).
The non-copying implementation is supported between certain pairs
of array types only; one constraint is that the array types must
have identical representations. In GHC, The following pairs of
array types have a non-copying O(1) implementation of
unsafeThaw. Because the optimised versions are enabled by
specialisations, you will need to compile with optimisation (-O) to
get them.
unsafeForeignPtrToStorableArray :: Ix i => ForeignPtr e -> (i, i) -> IO (StorableArray i e)Source
Construct a StorableArray from an arbitrary ForeignPtr. It is
the caller's responsibility to ensure that the ForeignPtr points to
an area of memory sufficient for the specified bounds.