malloc/dynarray_resize_clear.c

   1 /* Increase the size of a dynamic array and clear the new part.
   2    Copyright (C) 2017-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <dynarray.h>
  20 #include <string.h>
  21
  22 bool
  23 __libc_dynarray_resize_clear (struct dynarray_header *list, size_t size,
  24                               void *scratch, size_t element_size)
  25 {
  26   size_t old_size = list->used;
  27   if (!__libc_dynarray_resize (list, size, scratch, element_size))
  28     return false;
  29   /* __libc_dynarray_resize already checked for overflow.  */
  30   char *array = list->array;
  31   memset (array + (old_size * element_size), 0,
  32           (size - old_size) * element_size);
  33   return true;
  34 }
  35 libc_hidden_def (__libc_dynarray_resize_clear)