1#include <stdlib.h>
2#include <assert.h>
3#include <inttypes.h>
4
5#include "memalign.h"
6
7#define PTR_ALIGN(ptr, mask)   \
8	(char *)((uintptr_t)((ptr) + (mask)) & ~(mask))
9
10struct align_footer {
11	unsigned int offset;
12};
13
14void *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 - 1);
24		f = ret + size;
25		f->offset = (uintptr_t) ret - (uintptr_t) ptr;
26	}
27
28	return ret;
29}
30
31void fio_memfree(void *ptr, size_t size)
32{
33	struct align_footer *f = ptr + size;
34
35	free(ptr - f->offset);
36}
37