1/* Increase the size of a dynamic array.
2 Copyright (C) 2017-2020 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 <errno.h>
21#include <stdlib.h>
22#include <string.h>
23
24bool
25__libc_dynarray_resize (struct dynarray_header *list, size_t size,
26 void *scratch, size_t element_size)
27{
28 /* The existing allocation provides sufficient room. */
29 if (size <= list->allocated)
30 {
31 list->used = size;
32 return true;
33 }
34
35 /* Otherwise, use size as the new allocation size. The caller is
36 expected to provide the final size of the array, so there is no
37 over-allocation here. */
38
39 size_t new_size_bytes;
40 if (__builtin_mul_overflow (size, element_size, &new_size_bytes))
41 {
42 /* Overflow. */
43 __set_errno (ENOMEM);
44 return false;
45 }
46 void *new_array;
47 if (list->array == scratch)
48 {
49 /* The previous array was not heap-allocated. */
50 new_array = malloc (new_size_bytes);
51 if (new_array != NULL && list->array != NULL)
52 memcpy (new_array, list->array, list->used * element_size);
53 }
54 else
55 new_array = realloc (list->array, new_size_bytes);
56 if (new_array == NULL)
57 return false;
58 list->array = new_array;
59 list->allocated = size;
60 list->used = size;
61 return true;
62}
63libc_hidden_def (__libc_dynarray_resize)
64