1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (C) 1996
5 *	David L. Nugent.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef lint
30static const char rcsid[] =
31  "$FreeBSD: stable/11/usr.sbin/pw/bitmap.c 330449 2018-03-05 07:26:05Z eadler $";
32#endif /* not lint */
33
34#include <stdlib.h>
35#include <string.h>
36
37#include "bitmap.h"
38
39struct bitmap
40bm_alloc(int size)
41{
42	struct bitmap   bm;
43	int             szmap = (size / 8) + !!(size % 8);
44
45	bm.size = size;
46	bm.map = malloc(szmap);
47	if (bm.map)
48		memset(bm.map, 0, szmap);
49	return bm;
50}
51
52void
53bm_dealloc(struct bitmap * bm)
54{
55	free(bm->map);
56}
57
58static void
59bm_getmask(int *pos, unsigned char *bmask)
60{
61	*bmask = (unsigned char) (1 << (*pos % 8));
62	*pos /= 8;
63}
64
65void
66bm_setbit(struct bitmap * bm, int pos)
67{
68	unsigned char   bmask;
69
70	bm_getmask(&pos, &bmask);
71	bm->map[pos] |= bmask;
72}
73
74void
75bm_clrbit(struct bitmap * bm, int pos)
76{
77	unsigned char   bmask;
78
79	bm_getmask(&pos, &bmask);
80	bm->map[pos] &= ~bmask;
81}
82
83int
84bm_isset(struct bitmap * bm, int pos)
85{
86	unsigned char   bmask;
87
88	bm_getmask(&pos, &bmask);
89	return !!(bm->map[pos] & bmask);
90}
91
92int
93bm_firstunset(struct bitmap * bm)
94{
95	int             szmap = (bm->size / 8) + !!(bm->size % 8);
96	int             at = 0;
97	int             pos = 0;
98
99	while (pos < szmap) {
100		unsigned char   bmv = bm->map[pos++];
101		unsigned char   bmask = 1;
102
103		while (bmask & 0xff) {
104			if ((bmv & bmask) == 0)
105				return at;
106			bmask <<= 1;
107			++at;
108		}
109	}
110	return at;
111}
112
113int
114bm_lastset(struct bitmap * bm)
115{
116	int             szmap = (bm->size / 8) + !!(bm->size % 8);
117	int             at = 0;
118	int             pos = 0;
119	int             ofs = 0;
120
121	while (pos < szmap) {
122		unsigned char   bmv = bm->map[pos++];
123		unsigned char   bmask = 1;
124
125		while (bmask & 0xff) {
126			if ((bmv & bmask) != 0)
127				ofs = at;
128			bmask <<= 1;
129			++at;
130		}
131	}
132	return ofs;
133}
134