[fio.git] / lib / memalign.c

#include <assert.h>
#include <stdlib.h>

#include "memalign.h"
#include "smalloc.h"

#define PTR_ALIGN(ptr, mask)   \
	(char *)((uintptr_t)((ptr) + (mask)) & ~(mask))

struct align_footer {
	unsigned int offset;
};

void *__fio_memalign(size_t alignment, size_t size, malloc_fn fn)
{
	struct align_footer *f;
	void *ptr, *ret = NULL;

	assert(!(alignment & (alignment - 1)));

	ptr = fn(size + alignment + sizeof(*f) - 1);
	if (ptr) {
		ret = PTR_ALIGN(ptr, alignment - 1);
		f = ret + size;
		f->offset = (uintptr_t) ret - (uintptr_t) ptr;
	}

	return ret;
}

void __fio_memfree(void *ptr, size_t size, free_fn fn)
{
	struct align_footer *f = ptr + size;

	fn(ptr - f->offset);
}
Commit	Line	Data
	1	#include <assert.h>
	2	#include <stdlib.h>
	3
	4	#include "memalign.h"
	5	#include "smalloc.h"
	6
	7	#define PTR_ALIGN(ptr, mask) \
	8	(char *)((uintptr_t)((ptr) + (mask)) & ~(mask))
	9
	10	struct align_footer {
	11	unsigned int offset;
	12	};
	13
	14	void *__fio_memalign(size_t alignment, size_t size, malloc_fn fn)
	15	{
	16	struct align_footer *f;
	17	void ptr, ret = NULL;
	18
	19	assert(!(alignment & (alignment - 1)));
	20
	21	ptr = fn(size + alignment + sizeof(*f) - 1);
	22	if (ptr) {
	23	ret = PTR_ALIGN(ptr, alignment - 1);
	24	f = ret + size;
	25	f->offset = (uintptr_t) ret - (uintptr_t) ptr;
	26	}
	27
	28	return ret;
	29	}
	30
	31	void __fio_memfree(void *ptr, size_t size, free_fn fn)
	32	{
	33	struct align_footer *f = ptr + size;
	34
	35	fn(ptr - f->offset);
	36	}