memory.h File Reference

Types and functions for memory manipulation. More...

#include <geogram/basic/common.h>
#include <geogram/basic/assert.h>
#include <geogram/basic/numeric.h>
#include <geogram/basic/argused.h>
#include <vector>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

Go to the source code of this file.

Classes
struct	GEO::Memory::PointAlignment< DIM >
	Defines the memory alignment of points in a vector. More...
struct	GEO::Memory::PointAlignment< 2 >
	PointAlignment specialization for points of dimension 2. More...
struct	GEO::Memory::PointAlignment< 3 >
	PointAlignment specialization for points of dimension 3. More...
struct	GEO::Memory::PointAlignment< 4 >
	PointAlignment specialization for points of dimension 4. More...
struct	GEO::Memory::PointAlignment< 6 >
	PointAlignment specialization for points of dimension 6. More...
struct	GEO::Memory::PointAlignment< 8 >
	PointAlignment specialization for points of dimension 8. More...
class	GEO::Memory::aligned_allocator< T, ALIGN >
	An allocator that performs aligned memory allocations. More...
struct	GEO::Memory::aligned_allocator< T, ALIGN >::rebind< U >
	Defines the same allocator for other types. More...
class	GEO::vector< T >
	Vector with aligned memory allocation. More...
class	GEO::vector< bool >
	Specialization of vector for elements of type bool. More...

Namespaces
namespace	GEO
	Global Vorpaline namespace.
namespace	GEO::Memory
	Utilities for memory management.

Macros
#define	GEO_HAS_BIG_STACK
#define	GEO_MEMORY_ALIGNMENT   64
	Default memory alignment for efficient vector operations.
#define	geo_dim_alignment(dim)   GEO::Memory::PointAlignment<dim>::value
	Gets a point alignment.
#define	geo_assume_aligned(var, alignment)    *(void**) (&var) = __builtin_assume_aligned(var, alignment)
	Informs the compiler that a given pointer is memory-aligned.
#define	geo_aligned_alloca(size)    GEO::Memory::align(alloca(size + GEO_MEMORY_ALIGNMENT - 1))
	Allocates aligned memory on the stack.

Typedefs
typedef unsigned char	GEO::Memory::byte
	Unsigned byte type.
typedef unsigned char	GEO::Memory::word8
	Unsigned 8 bits integer.
typedef unsigned short	GEO::Memory::word16
	Unsigned 16 bits integer.
typedef unsigned int	GEO::Memory::word32
	Unsigned 32 bits integer.
typedef byte *	GEO::Memory::pointer
	Pointer to unsigned byte(s)
typedef void(*	GEO::Memory::function_pointer) ()
	Generic function pointer.

Functions
void	GEO::Memory::clear (void *addr, size_t size)
	Clears a memory block.
void	GEO::Memory::copy (void *to, const void *from, size_t size)
	Copies a memory block.
pointer	GEO::Memory::function_pointer_to_generic_pointer (function_pointer fptr)
	Converts a function pointer to a generic pointer.
function_pointer	GEO::Memory::generic_pointer_to_function_pointer (pointer ptr)
	Converts a generic pointer to a function pointer.
function_pointer	GEO::Memory::generic_pointer_to_function_pointer (void *ptr)
	Converts a generic pointer to a function pointer.
void *	GEO::Memory::aligned_malloc (size_t size, size_t alignment=GEO_MEMORY_ALIGNMENT)
	Allocates aligned memory.
void	GEO::Memory::aligned_free (void *p)
	Deallocates aligned memory.
bool	GEO::Memory::is_aligned (void *p, size_t alignment=GEO_MEMORY_ALIGNMENT)
	Checks whether a pointer is aligned.
void *	GEO::Memory::align (void *p)
	Returns the smallest aligned memory address from p.
template<typename T1 , int A1, typename T2 , int A2>
bool	GEO::Memory::operator== (const aligned_allocator< T1, A1 > &, const aligned_allocator< T2, A2 > &)
	Tests whether two aligned_allocators are equal.
template<typename T1 , int A1, typename T2 , int A2>
bool	GEO::Memory::operator!= (const aligned_allocator< T1, A1 > &, const aligned_allocator< T2, A2 > &)
	Tests whether two aligned_allocators are different.

Detailed Description

Types and functions for memory manipulation.

Definition in file memory.h.

Macro Definition Documentation

geo_aligned_alloca

#define geo_aligned_alloca

(

size

)

GEO::Memory::align(alloca(size + GEO_MEMORY_ALIGNMENT - 1))

Allocates aligned memory on the stack.

Allocates size bytes on the stack. The returned address is guaranteed to be aligned on GEO_MEMORY_ALIGNMENT bytes. To guarantee the memory alignment, the function may allocate more than size, but not more than GEO_MEMORY_ALIGNMENT - 1.

Parameters

[in]

size

Number of bytes to allocate.

Returns

An aligned pointer to a memory block of size bytes.

Definition at line 446 of file memory.h.

geo_assume_aligned

#define geo_assume_aligned	(		var,
			alignment
	)		*(void**) (&var) = __builtin_assume_aligned(var, alignment)

Informs the compiler that a given pointer is memory-aligned.

It helps the compiler vectorizing loops, i.e. generating SSE/AVX/... code.

Parameters

[in]	var	a pointer variable in the current scope
[in]	alignment	the memory alignment (must be a power of 2)

Example

double* p = ...;
geo_assume_aligned(p,alignment);

Note

Memory alignment is not supported under Android.

C++20 has std::assume_aligned()

Definition at line 375 of file memory.h.

geo_dim_alignment

#define geo_dim_alignment

(

dim

)

GEO::Memory::PointAlignment<dim>::value

Gets a point alignment.

This gives the alignment of a point of dimension dim within an array of points aligned on GEO_MEMORY_ALIGNMENT bytes

Parameters

[in]

dim

the dimension of the point

See also

GEO::Memory::PointAlignment

GEO_MEMORY_ALIGNMENT

Definition at line 270 of file memory.h.

GEO_HAS_BIG_STACK

#define GEO_HAS_BIG_STACK

Definition at line 77 of file memory.h.

GEO_MEMORY_ALIGNMENT

#define GEO_MEMORY_ALIGNMENT   64

Default memory alignment for efficient vector operations.

The memory alignment is given in bytes. Here is a list of commonly used alignment values for various architectures:

• SSE: 16
• AVX: 32
• AVX-512: 64

Definition at line 196 of file memory.h.