1 /*- 2 * Copyright (C) 1996 3 * David L. Nugent. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/usr.sbin/pw/bitmap.c,v 1.5 1999/08/28 01:19:15 peter Exp $ 27 * $DragonFly: src/usr.sbin/pw/bitmap.c,v 1.2 2003/06/17 04:30:01 dillon Exp $ 28 */ 29 30 #include <stdlib.h> 31 #include <string.h> 32 33 #include "bitmap.h" 34 35 struct bitmap 36 bm_alloc(int size) 37 { 38 struct bitmap bm; 39 int szmap = (size / 8) + !!(size % 8); 40 41 bm.size = size; 42 bm.map = malloc(szmap); 43 if (bm.map) 44 memset(bm.map, 0, szmap); 45 return bm; 46 } 47 48 void 49 bm_dealloc(struct bitmap * bm) 50 { 51 if (bm->map) 52 free(bm->map); 53 } 54 55 static void 56 bm_getmask(int *pos, unsigned char *bmask) 57 { 58 *bmask = (unsigned char) (1 << (*pos % 8)); 59 *pos /= 8; 60 } 61 62 void 63 bm_setbit(struct bitmap * bm, int pos) 64 { 65 unsigned char bmask; 66 67 bm_getmask(&pos, &bmask); 68 bm->map[pos] |= bmask; 69 } 70 71 void 72 bm_clrbit(struct bitmap * bm, int pos) 73 { 74 unsigned char bmask; 75 76 bm_getmask(&pos, &bmask); 77 bm->map[pos] &= ~bmask; 78 } 79 80 int 81 bm_isset(struct bitmap * bm, int pos) 82 { 83 unsigned char bmask; 84 85 bm_getmask(&pos, &bmask); 86 return !!(bm->map[pos] & bmask); 87 } 88 89 int 90 bm_firstunset(struct bitmap * bm) 91 { 92 int szmap = (bm->size / 8) + !!(bm->size % 8); 93 int at = 0; 94 int pos = 0; 95 96 while (pos < szmap) { 97 unsigned char bmv = bm->map[pos++]; 98 unsigned char bmask = 1; 99 100 while (bmask & 0xff) { 101 if ((bmv & bmask) == 0) 102 return at; 103 bmask <<= 1; 104 ++at; 105 } 106 } 107 return at; 108 } 109 110 int 111 bm_lastset(struct bitmap * bm) 112 { 113 int szmap = (bm->size / 8) + !!(bm->size % 8); 114 int at = 0; 115 int pos = 0; 116 int ofs = 0; 117 118 while (pos < szmap) { 119 unsigned char bmv = bm->map[pos++]; 120 unsigned char bmask = 1; 121 122 while (bmask & 0xff) { 123 if ((bmv & bmask) != 0) 124 ofs = at; 125 bmask <<= 1; 126 ++at; 127 } 128 } 129 return ofs; 130 } 131