Alignment manipulation

Aligned memory allocator

template <class T, size_t Align>
class xsimd::aligned_allocator

Allocator for aligned memory.

The aligned_allocator class template is an allocator that performs memory allocation aligned by the specified value.

Template Parameters

  • T: type of objects to allocate.

  • Align: alignment in bytes.

Public Functions

XSIMD_INLINE aligned_allocator()

Default constructor.

XSIMD_INLINE aligned_allocator(const aligned_allocator &rhs)

Copy constructor.

template <class U>
XSIMD_INLINE aligned_allocator(const aligned_allocator<U, Align> &rhs)

Extended copy constructor.

XSIMD_INLINE ~aligned_allocator()

Destructor.

XSIMD_INLINE auto xsimd::aligned_allocator::address(reference r)

Returns the actual address of r even in presence of overloaded operator&.

Return

the actual address of r.

Parameters

  • r: the object to acquire address of.

XSIMD_INLINE auto xsimd::aligned_allocator::address(const_reference r) const

Returns the actual address of r even in presence of overloaded operator&.

Return

the actual address of r.

Parameters

  • r: the object to acquire address of.

XSIMD_INLINE auto xsimd::aligned_allocator::allocate(size_type n, const void * hint = 0)

Allocates n * sizeof(T) bytes of uninitialized memory, aligned by A.

The alignment may require some extra memory allocation.

Return

a pointer to the first byte of a memory block suitably aligned and sufficient to hold an array of n objects of type T.

Parameters

  • n: the number of objects to allocate storage for.

  • hint: unused parameter provided for standard compliance.

XSIMD_INLINE void xsimd::aligned_allocator::deallocate(pointer p, size_type n)

Deallocates the storage referenced by the pointer p, which must be a pointer obtained by an earlier call to allocate().

The argument n must be equal to the first argument of the call to allocate() that originally produced p; otherwise, the behavior is undefined.

Parameters

XSIMD_INLINE auto xsimd::aligned_allocator::max_size() const

Returns the maximum theoretically possible value of n, for which the call allocate(n, 0) could succeed.

Return

the maximum supported allocated size.

XSIMD_INLINE auto xsimd::aligned_allocator::size_max() const

This method is deprecated, use max_size() instead.

template <class U, class… Args>
XSIMD_INLINE void xsimd::aligned_allocator::construct(U * p, Args &&... args)

Constructs an object of type T in allocated uninitialized memory pointed to by p, using placement-new.

Parameters

  • p: pointer to allocated uninitialized memory.

  • args: the constructor arguments to use.

template <class U>
XSIMD_INLINE void xsimd::aligned_allocator::destroy(U * p)

Calls the destructor of the object pointed to by p.

Parameters

  • p: pointer to the object that is going to be destroyed.

Alignement checker

template <class Arch = default_arch>
XSIMD_INLINE bool xsimd::is_aligned(void const * ptr)

Checks whether pointer ptr is aligned according the alignment requirements of Arch.

Return

true if the alignment requirements are met