1  /* Increase the size of a dynamic array.
       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  #ifndef _LIBC
      20  # include <libc-config.h>
      21  #endif
      22  
      23  #include <dynarray.h>
      24  #include <errno.h>
      25  #include <stdckdint.h>
      26  #include <stdlib.h>
      27  #include <string.h>
      28  
      29  bool
      30  __libc_dynarray_resize (struct dynarray_header *list, size_t size,
      31                          void *scratch, size_t element_size)
      32  {
      33    /* The existing allocation provides sufficient room.  */
      34    if (size <= list->allocated)
      35      {
      36        list->used = size;
      37        return true;
      38      }
      39  
      40    /* Otherwise, use size as the new allocation size.  The caller is
      41       expected to provide the final size of the array, so there is no
      42       over-allocation here.  */
      43  
      44    size_t new_size_bytes;
      45    if (ckd_mul (&new_size_bytes, size, element_size))
      46      {
      47        /* Overflow.  */
      48        __set_errno (ENOMEM);
      49        return false;
      50      }
      51    void *new_array;
      52    if (list->array == scratch)
      53      {
      54        /* The previous array was not heap-allocated.  */
      55        new_array = malloc (new_size_bytes);
      56        if (new_array != NULL && list->array != NULL)
      57          memcpy (new_array, list->array, list->used * element_size);
      58      }
      59    else
      60      new_array = realloc (list->array, new_size_bytes);
      61    if (new_array == NULL)
      62      return false;
      63    list->array = new_array;
      64    list->allocated = size;
      65    list->used = size;
      66    return true;
      67  }
      68  libc_hidden_def (__libc_dynarray_resize)