1 /* Hash table for sequential list, set, and map data type.
2 Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2006.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program 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
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* Common code of
19 gl_linkedhash_list.c, gl_avltreehash_list.c, gl_rbtreehash_list.c,
20 gl_linkedhash_set.c, gl_hash_set.c,
21 gl_linkedhash_map.c, gl_hash_map.c. */
22
23 #include "gl_anyhash_primes.h"
24
25 /* Resizes the hash table with a new estimated size. */
26 static void
hash_resize(CONTAINER_T container,size_t estimate)27 hash_resize (CONTAINER_T container, size_t estimate)
28 {
29 size_t new_size = next_prime (estimate);
30
31 if (new_size > container->table_size)
32 {
33 gl_hash_entry_t *old_table = container->table;
34 /* Allocate the new table. */
35 gl_hash_entry_t *new_table;
36 size_t i;
37
38 if (size_overflow_p (xtimes (new_size, sizeof (gl_hash_entry_t))))
39 goto fail;
40 new_table =
41 (gl_hash_entry_t *) calloc (new_size, sizeof (gl_hash_entry_t));
42 if (new_table == NULL)
43 goto fail;
44
45 /* Iterate through the entries of the old table. */
46 for (i = container->table_size; i > 0; )
47 {
48 gl_hash_entry_t node = old_table[--i];
49
50 while (node != NULL)
51 {
52 gl_hash_entry_t next = node->hash_next;
53 /* Add the entry to the new table. */
54 size_t bucket = node->hashcode % new_size;
55 node->hash_next = new_table[bucket];
56 new_table[bucket] = node;
57
58 node = next;
59 }
60 }
61
62 container->table = new_table;
63 container->table_size = new_size;
64 free (old_table);
65 }
66 return;
67
68 fail:
69 /* Just continue without resizing the table. */
70 return;
71 }
72
73 /* Resizes the hash table if needed, after CONTAINER_COUNT (container) was
74 incremented. */
75 static void
hash_resize_after_add(CONTAINER_T container)76 hash_resize_after_add (CONTAINER_T container)
77 {
78 size_t count = CONTAINER_COUNT (container);
79 size_t estimate = xsum (count, count / 2); /* 1.5 * count */
80 if (estimate > container->table_size)
81 hash_resize (container, estimate);
82 }
83