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