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 <intprops.h>
22#include <stdlib.h>
23#include <string.h>
24
25bool
26__libc_dynarray_emplace_enlarge (struct dynarray_header *list,
27 void *scratch, size_t element_size)
28{
29 size_t new_allocated;
30 if (list->allocated == 0)
31 {
32 /* No scratch buffer provided. Choose a reasonable default
33 size. */
34 if (element_size < 4)
35 new_allocated = 16;
36 else if (element_size < 8)
37 new_allocated = 8;
38 else
39 new_allocated = 4;
40 }
41 else
42 /* Increase the allocated size, using an exponential growth
43 policy. */
44 {
45 new_allocated = list->allocated + list->allocated / 2 + 1;
46 if (new_allocated <= list->allocated)
47 {
48 /* Overflow. */
49 __set_errno (ENOMEM);
50 return false;
51 }
52 }
53
54 size_t new_size;
55 if (INT_MULTIPLY_WRAPV (new_allocated, element_size, &new_size))
56 return false;
57 void *new_array;
58 if (list->array == scratch)
59 {
60 /* The previous array was not heap-allocated. */
61 new_array = malloc (new_size);
62 if (new_array != NULL && list->array != NULL)
63 memcpy (new_array, list->array, list->used * element_size);
64 }
65 else
66 new_array = realloc (list->array, new_size);
67 if (new_array == NULL)
68 return false;
69 list->array = new_array;
70 list->allocated = new_allocated;
71 return true;
72}
73libc_hidden_def (__libc_dynarray_emplace_enlarge)
74