OS_Memory.h File Reference

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Classes
class	ACE_bad_alloc_class
Functions
Efficiently compute aligned pointers to powers of 2 boundaries.
unsigned int	ACE_align_binary (unsigned int ptr, unsigned int alignment)
	Return the next integer aligned to a required boundary.
uintptr_t	ACE_align_binary (uintptr_t ptr, uintptr_t alignment)
	Return the next integer aligned to a required boundary.
char *	ACE_ptr_align_binary (char const *ptr, unsigned int alignment)
	Return the next address aligned to a required boundary.
char *	ACE_ptr_align_binary (unsigned char const *ptr, unsigned int alignment)
	Return the next address aligned to a required boundary.
char *	ACE_ptr_align_binary (char const *ptr, uintptr_t alignment)
	Return the next address aligned to a required boundary.
char *	ACE_ptr_align_binary (unsigned char const *ptr, uintptr_t alignment)
	Return the next address aligned to a required boundary.
Variables
ACE_BEGIN_VERSIONED_NAMESPACE_DECL typedef char *	ACE_MALLOC_T

---

Detailed Description

Id

OS_Memory.h 86400 2009-08-06 13:52:28Z schmidt

Author:

Doug Schmidt <schmidt@cs.wustl.edu>

Jesper S. M|ller<stophph@diku.dk>

and a cast of thousands...

Definition in file OS_Memory.h.

---

Function Documentation

uintptr_t ACE_align_binary	(	uintptr_t	ptr,
		uintptr_t	alignment
	)			[inline]

Return the next integer aligned to a required boundary.

Efficiently align "value" up to "alignment", knowing that all such boundaries are binary powers and that we're using two's complement arithmetic.

Since the alignment is a power of two its binary representation is:

alignment = 0...010...0

hence

alignment - 1 = 0...001...1 = T1

so the complement is:

~(alignment - 1) = 1...110...0 = T2

Notice that there is a multiple of alignment in the range [

,

+ T1], also notice that if

X = (

+ T1 ) & T2

then

<= X <=

+ T1

because the & operator only changes the last bits, and since X is a multiple of alignment (its last bits are zero) we have found the multiple we wanted.

Parameters:

	ptr	the base pointer
	alignment	the required alignment

Definition at line 296 of file OS_Memory.h.

{
  uintptr_t const tmp = alignment - 1;
  return (ptr + tmp) & (~tmp);
}

unsigned int ACE_align_binary	(	unsigned int	ptr,
		unsigned int	alignment
	)			[inline]

Return the next integer aligned to a required boundary.

Efficiently align "value" up to "alignment", knowing that all such boundaries are binary powers and that we're using two's complement arithmetic.

Since the alignment is a power of two its binary representation is:

alignment = 0...010...0

hence

alignment - 1 = 0...001...1 = T1

so the complement is:

~(alignment - 1) = 1...110...0 = T2

Notice that there is a multiple of alignment in the range [

,

+ T1], also notice that if

X = (

+ T1 ) & T2

then

<= X <=

+ T1

because the & operator only changes the last bits, and since X is a multiple of alignment (its last bits are zero) we have found the multiple we wanted.

Parameters:

	ptr	the base pointer
	alignment	the required alignment

Definition at line 289 of file OS_Memory.h.

{
  unsigned int const tmp = alignment - 1;
  return (ptr + tmp) & (~tmp);
}

char* ACE_ptr_align_binary	(	unsigned char const *	ptr,
		uintptr_t	alignment
	)			[inline]

Return the next address aligned to a required boundary.

Definition at line 332 of file OS_Memory.h.

{
  return
    ACE_ptr_align_binary (reinterpret_cast<char const *> (ptr), alignment);
}

char* ACE_ptr_align_binary	(	char const *	ptr,
		uintptr_t	alignment
	)			[inline]

Return the next address aligned to a required boundary.

Definition at line 323 of file OS_Memory.h.

{
  return
    reinterpret_cast<char *> (
      ACE_align_binary (reinterpret_cast<uintptr_t> (ptr), alignment));
}

char* ACE_ptr_align_binary	(	unsigned char const *	ptr,
		unsigned int	alignment
	)			[inline]

Return the next address aligned to a required boundary.

Definition at line 315 of file OS_Memory.h.

{
  return
    ACE_ptr_align_binary (reinterpret_cast<char const *> (ptr), alignment);
}

char* ACE_ptr_align_binary	(	char const *	ptr,
		unsigned int	alignment
	)			[inline]

Return the next address aligned to a required boundary.

Definition at line 306 of file OS_Memory.h.

{
  return
    reinterpret_cast<char *> (
      ACE_align_binary (reinterpret_cast<unsigned int> (ptr), alignment));
}

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Variable Documentation

typedef void * ACE_MALLOC_T

Definition at line 62 of file OS_Memory.h.