malloc/dynarray_finalize.c

   1 /* Copy the dynamically-allocated area to an explicitly-sized heap allocation.
   2    Copyright (C) 2017-2023 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 <stdlib.h>
  21 #include <string.h>
  22
  23 bool
  24 __libc_dynarray_finalize (struct dynarray_header *list,
  25                           void *scratch, size_t element_size,
  26                           struct dynarray_finalize_result *result)
  27 {
  28   if (__dynarray_error (list))
  29     /* The caller will reported the deferred error.  */
  30     return false;
  31
  32   size_t used = list->used;
  33
  34   /* Empty list.  */
  35   if (used == 0)
  36     {
  37       /* An empty list could still be backed by a heap-allocated
  38          array.  Free it if necessary.  */
  39       if (list->array != scratch)
  40         free (list->array);
  41       *result = (struct dynarray_finalize_result) { NULL, 0 };
  42       return true;
  43     }
  44
  45   size_t allocation_size = used * element_size;
  46   void *heap_array = malloc (allocation_size);
  47   if (heap_array != NULL)
  48     {
  49       /* The new array takes ownership of the strings.  */
  50       if (list->array != NULL)
  51         memcpy (heap_array, list->array, allocation_size);
  52       if (list->array != scratch)
  53         free (list->array);
  54       *result = (struct dynarray_finalize_result)
  55         { .array = heap_array, .length = used };
  56       return true;
  57     }
  58   else
  59     /* The caller will perform the freeing operation.  */
  60     return false;
  61 }
  62 libc_hidden_def (__libc_dynarray_finalize)