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 <intprops.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 (INT_MULTIPLY_WRAPV (size, element_size, &new_size_bytes))
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)