1 /* $NetBSD: memalign.c,v 1.1.1.1 2016/01/13 21:42:18 christos Exp $ */
2
3 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; see the file COPYING.LIB. If
17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
18 Cambridge, MA 02139, USA. */
19
20 #ifndef _MALLOC_INTERNAL
21 #define _MALLOC_INTERNAL
22 #include <malloc.h>
23 #endif
24
25 __ptr_t (*__memalign_hook) __P ((size_t __size, size_t __alignment));
26
27 __ptr_t
memalign(alignment,size)28 memalign (alignment, size)
29 __malloc_size_t alignment;
30 __malloc_size_t size;
31 {
32 __ptr_t result;
33 unsigned long int adj;
34
35 if (__memalign_hook)
36 return (*__memalign_hook) (alignment, size);
37
38 size = ((size + alignment - 1) / alignment) * alignment;
39
40 result = malloc (size);
41 if (result == NULL)
42 return NULL;
43 adj = (unsigned long int) ((unsigned long int) ((char *) result -
44 (char *) NULL)) % alignment;
45 if (adj != 0)
46 {
47 struct alignlist *l;
48 for (l = _aligned_blocks; l != NULL; l = l->next)
49 if (l->aligned == NULL)
50 /* This slot is free. Use it. */
51 break;
52 if (l == NULL)
53 {
54 l = (struct alignlist *) malloc (sizeof (struct alignlist));
55 if (l == NULL)
56 {
57 free (result);
58 return NULL;
59 }
60 l->next = _aligned_blocks;
61 _aligned_blocks = l;
62 }
63 l->exact = result;
64 result = l->aligned = (char *) result + alignment - adj;
65 }
66
67 return result;
68 }
69