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 #include <stdlib.h> 30 #include <string.h> 31 32 #include "bitmap.h" 33 34 struct bitmap 35 bm_alloc(int size) 36 { 37 struct bitmap bm; 38 int szmap = (size / 8) + !!(size % 8); 39 40 bm.size = size; 41 bm.map = malloc(szmap); 42 if (bm.map) 43 memset(bm.map, 0, szmap); 44 return bm; 45 } 46 47 void 48 bm_dealloc(struct bitmap * bm) 49 { 50 free(bm->map); 51 } 52 53 static void 54 bm_getmask(int *pos, unsigned char *bmask) 55 { 56 *bmask = (unsigned char) (1 << (*pos % 8)); 57 *pos /= 8; 58 } 59 60 void 61 bm_setbit(struct bitmap * bm, int pos) 62 { 63 unsigned char bmask; 64 65 bm_getmask(&pos, &bmask); 66 bm->map[pos] |= bmask; 67 } 68 69 void 70 bm_clrbit(struct bitmap * bm, int pos) 71 { 72 unsigned char bmask; 73 74 bm_getmask(&pos, &bmask); 75 bm->map[pos] &= ~bmask; 76 } 77 78 int 79 bm_isset(struct bitmap * bm, int pos) 80 { 81 unsigned char bmask; 82 83 bm_getmask(&pos, &bmask); 84 return !!(bm->map[pos] & bmask); 85 } 86 87 int 88 bm_firstunset(struct bitmap * bm) 89 { 90 int szmap = (bm->size / 8) + !!(bm->size % 8); 91 int at = 0; 92 int pos = 0; 93 94 while (pos < szmap) { 95 unsigned char bmv = bm->map[pos++]; 96 unsigned char bmask = 1; 97 98 while (bmask & 0xff) { 99 if ((bmv & bmask) == 0) 100 return at; 101 bmask <<= 1; 102 ++at; 103 } 104 } 105 return at; 106 } 107 108 int 109 bm_lastset(struct bitmap * bm) 110 { 111 int szmap = (bm->size / 8) + !!(bm->size % 8); 112 int at = 0; 113 int pos = 0; 114 int ofs = 0; 115 116 while (pos < szmap) { 117 unsigned char bmv = bm->map[pos++]; 118 unsigned char bmask = 1; 119 120 while (bmask & 0xff) { 121 if ((bmv & bmask) != 0) 122 ofs = at; 123 bmask <<= 1; 124 ++at; 125 } 126 } 127 return ofs; 128 } 129