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 General Public
7 License as published by the Free Software Foundation; either
8 version 3 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 General Public License for more details.
14
15 You should have received a copy of the GNU 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
__libc_dynarray_emplace_enlarge(struct dynarray_header * list,void * scratch,size_t element_size)30 __libc_dynarray_emplace_enlarge (struct dynarray_header *list,
31 void *scratch, size_t element_size)
32 {
33 size_t new_allocated;
34 if (list->allocated == 0)
35 {
36 /* No scratch buffer provided. Choose a reasonable default
37 size. */
38 if (element_size < 4)
39 new_allocated = 16;
40 else if (element_size < 8)
41 new_allocated = 8;
42 else
43 new_allocated = 4;
44 }
45 else
46 /* Increase the allocated size, using an exponential growth
47 policy. */
48 {
49 new_allocated = list->allocated + list->allocated / 2 + 1;
50 if (new_allocated <= list->allocated)
51 {
52 /* Overflow. */
53 __set_errno (ENOMEM);
54 return false;
55 }
56 }
57
58 size_t new_size;
59 if (INT_MULTIPLY_WRAPV (new_allocated, element_size, &new_size))
60 return false;
61 void *new_array;
62 if (list->array == scratch)
63 {
64 /* The previous array was not heap-allocated. */
65 new_array = malloc (new_size);
66 if (new_array != NULL && list->array != NULL)
67 memcpy (new_array, list->array, list->used * element_size);
68 }
69 else
70 new_array = realloc (list->array, new_size);
71 if (new_array == NULL)
72 return false;
73 list->array = new_array;
74 list->allocated = new_allocated;
75 return true;
76 }
77 libc_hidden_def (__libc_dynarray_emplace_enlarge)
78