[fio.git] / memalign.c

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

#include "memalign.h"

struct align_footer {
	unsigned int offset;
};

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

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

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

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

	return ret;
}

void fio_memfree(void *ptr, size_t size)
{
	struct align_footer *f = ptr + size;

	free(ptr - f->offset);
}
Commit	Line	Data
	1	#include <stdlib.h>
	2	#include <assert.h>
	3	#include <inttypes.h>
	4
	5	#include "memalign.h"
	6
	7	struct align_footer {
	8	unsigned int offset;
	9	};
	10
	11	#define PTR_ALIGN(ptr, mask) \
	12	(char *) (((uintptr_t) ((ptr) + (mask)) & ~(mask)))
	13
	14	void *fio_memalign(size_t alignment, size_t size)
	15	{
	16	struct align_footer *f;
	17	void ptr, ret = NULL;
	18
	19	assert(!(alignment & (alignment - 1)));
	20
	21	ptr = malloc(size + alignment + size + sizeof(*f) - 1);
	22	if (ptr) {
	23	ret = PTR_ALIGN(ptr, alignment);
	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)
	32	{
	33	struct align_footer *f = ptr + size;
	34
	35	free(ptr - f->offset);
	36	}