1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 30 static const char rcsid[] = 31 "$FreeBSD$"; 32 #endif /* not lint */ 33 34 #include <stdlib.h> 35 #include <string.h> 36 37 #include "bitmap.h" 38 39 struct bitmap 40 bm_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 52 void 53 bm_dealloc(struct bitmap * bm) 54 { 55 free(bm->map); 56 } 57 58 static void 59 bm_getmask(int *pos, unsigned char *bmask) 60 { 61 *bmask = (unsigned char) (1 << (*pos % 8)); 62 *pos /= 8; 63 } 64 65 void 66 bm_setbit(struct bitmap * bm, int pos) 67 { 68 unsigned char bmask; 69 70 bm_getmask(&pos, &bmask); 71 bm->map[pos] |= bmask; 72 } 73 74 void 75 bm_clrbit(struct bitmap * bm, int pos) 76 { 77 unsigned char bmask; 78 79 bm_getmask(&pos, &bmask); 80 bm->map[pos] &= ~bmask; 81 } 82 83 int 84 bm_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 92 int 93 bm_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 } 112 113 int 114 bm_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