lib/aligned_alloc.c

   1 /* An aligned_alloc() function that works around platform bugs.
   2    Copyright (C) 2020-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <stdlib.h>
  21
  22 #include <errno.h>
  23
  24 void *
  25 aligned_alloc (size_t alignment, size_t size)
  26 #undef aligned_alloc
  27 {
  28   if (alignment != 0 && (alignment & (alignment - 1)) == 0)
  29     {
  30       /* alignment is a power of 2.  */
  31       if (size == 0)
  32         size = 1;
  33       if (alignment >= sizeof (void *))
  34         {
  35           /* Make size a multiple of alignment.  */
  36           size = (size + (alignment - 1)) & -alignment;
  37           if (size > 0)
  38             return aligned_alloc (alignment, size);
  39           else
  40             {
  41               errno = ENOMEM;
  42               return NULL;
  43             }
  44         }
  45       else
  46         return malloc (size);
  47     }
  48   else
  49     {
  50       errno = EINVAL;
  51       return NULL;
  52     }
  53 }