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 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