1// SPDX-License-Identifier: MIT
2/*
3 * Stupid implementation of pointer -> pointer map.
4 *
5 * Copyright (c) 2017 Luc Van Oostenryck.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 * THE SOFTWARE.
24 */
25
26#include "ptrmap.h"
27#include "allocate.h"
28#include <stddef.h>
29
30#define	MAP_NR	7
31
32struct ptrpair {
33	void *key;
34	void *val;
35};
36struct ptrmap {
37	struct ptrmap *next;
38	int nr;
39	struct ptrpair pairs[MAP_NR];
40};
41
42DECLARE_ALLOCATOR(ptrmap);
43ALLOCATOR(ptrmap, "ptrmap");
44
45void __ptrmap_add(struct ptrmap **mapp, void *key, void *val)
46{
47	struct ptrmap *head = *mapp;
48	struct ptrmap *newmap;
49	struct ptrmap *map;
50	struct ptrpair *pair;
51	int nr;
52
53	if ((map = head)) {
54		struct ptrmap *next = map->next;
55		if (next)		// head is full
56			map = next;
57		if ((nr = map->nr) < MAP_NR)
58			goto oldmap;
59	}
60
61	// need a new block
62	newmap = __alloc_ptrmap(0);
63	if (!head) {
64		*mapp = newmap;
65	} else {
66		newmap->next = head->next;
67		head->next = newmap;
68	}
69	map = newmap;
70	nr = 0;
71
72oldmap:
73	pair = &map->pairs[nr];
74	pair->key = key;
75	pair->val = val;
76	map->nr = ++nr;
77}
78
79void *__ptrmap_lookup(struct ptrmap *map, void *key)
80{
81	for (; map; map = map->next) {
82		int i, n = map->nr;
83		for (i = 0; i < n; i++) {
84			struct ptrpair *pair = &map->pairs[i];
85			if (pair->key == key)
86				return pair->val;
87		}
88	}
89	return NULL;
90}
91
92void __ptrmap_update(struct ptrmap **mapp, void *key, void *val)
93{
94	struct ptrmap *map = *mapp;
95
96	for (; map; map = map->next) {
97		int i, n = map->nr;
98		for (i = 0; i < n; i++) {
99			struct ptrpair *pair = &map->pairs[i];
100			if (pair->key == key) {
101				if (pair->val != val)
102					pair->val = val;
103				return;
104			}
105		}
106	}
107
108	__ptrmap_add(mapp, key, val);
109}
110