/* Increase the size of a dynamic array in preparation of an emplace operation.

   Copyright (C) 2017-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <dynarray.h>

#include <errno.h>

#include <malloc-internal.h>

#include <stdlib.h>

#include <string.h>

bool

__libc_dynarray_emplace_enlarge (struct dynarray_header *list,

                                 void *scratch, size_t element_size)

{

  size_t new_allocated;

  if (list->allocated == 0)

    {

      /* No scratch buffer provided.  Choose a reasonable default

         size.  */

      if (element_size < 4)

        new_allocated = 16;

      else if (element_size < 8)

        new_allocated = 8;

      else

        new_allocated = 4;

    }

  else

    /* Increase the allocated size, using an exponential growth

       policy.  */

    {

      new_allocated = list->allocated + list->allocated / 2 + 1;

      if (new_allocated <= list->allocated)

        {

          /* Overflow.  */

          __set_errno (ENOMEM);

          return false;

        }

    }

  size_t new_size;

  if (check_mul_overflow_size_t (new_allocated, element_size, &new_size))

    return false;

  void *new_array;

  if (list->array == scratch)

    {

      /* The previous array was not heap-allocated.  */

      new_array = malloc (new_size);

      if (new_array != NULL && list->array != NULL)

        memcpy (new_array, list->array, list->used * element_size);

    }

  else

    new_array = realloc (list->array, new_size);

  if (new_array == NULL)

    return false;

  list->array = new_array;

  list->allocated = new_allocated;

  return true;

}

libc_hidden_def (__libc_dynarray_emplace_enlarge)