1/* Increase the size of a dynamic array in preparation of an emplace operation.
2 Copyright (C) 2017-2021 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_emplace_enlarge (struct dynarray_header *list,
26 void *scratch, size_t element_size)
27{
28 size_t new_allocated;
29 if (list->allocated == 0)
30 {
31 /* No scratch buffer provided. Choose a reasonable default
32 size. */
33 if (element_size < 4)
34 new_allocated = 16;
35 else if (element_size < 8)
36 new_allocated = 8;
37 else
38 new_allocated = 4;
39 }
40 else
41 /* Increase the allocated size, using an exponential growth
42 policy. */
43 {
44 new_allocated = list->allocated + list->allocated / 2 + 1;
45 if (new_allocated <= list->allocated)
46 {
47 /* Overflow. */
48 __set_errno (ENOMEM);
49 return false;
50 }
51 }
52
53 size_t new_size;
54 if (__builtin_mul_overflow (new_allocated, element_size, &new_size))
55 return false;
56 void *new_array;
57 if (list->array == scratch)
58 {
59 /* The previous array was not heap-allocated. */
60 new_array = malloc (new_size);
61 if (new_array != NULL && list->array != NULL)
62 memcpy (new_array, list->array, list->used * element_size);
63 }
64 else
65 new_array = realloc (list->array, new_size);
66 if (new_array == NULL)
67 return false;
68 list->array = new_array;
69 list->allocated = new_allocated;
70 return true;
71}
72libc_hidden_def (__libc_dynarray_emplace_enlarge)
73