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 27 #ifndef lint 28 static const char rcsid[] = 29 "$FreeBSD$"; 30 #endif /* not lint */ 31 32 #include <stdlib.h> 33 #include <string.h> 34 35 #include "bitmap.h" 36 37 struct bitmap 38 bm_alloc(int size) 39 { 40 struct bitmap bm; 41 int szmap = (size / 8) + !!(size % 8); 42 43 bm.size = size; 44 bm.map = malloc(szmap); 45 if (bm.map) 46 memset(bm.map, 0, szmap); 47 return bm; 48 } 49 50 void 51 bm_dealloc(struct bitmap * bm) 52 { 53 free(bm->map); 54 } 55 56 static void 57 bm_getmask(int *pos, unsigned char *bmask) 58 { 59 *bmask = (unsigned char) (1 << (*pos % 8)); 60 *pos /= 8; 61 } 62 63 void 64 bm_setbit(struct bitmap * bm, int pos) 65 { 66 unsigned char bmask; 67 68 bm_getmask(&pos, &bmask); 69 bm->map[pos] |= bmask; 70 } 71 72 void 73 bm_clrbit(struct bitmap * bm, int pos) 74 { 75 unsigned char bmask; 76 77 bm_getmask(&pos, &bmask); 78 bm->map[pos] &= ~bmask; 79 } 80 81 int 82 bm_isset(struct bitmap * bm, int pos) 83 { 84 unsigned char bmask; 85 86 bm_getmask(&pos, &bmask); 87 return !!(bm->map[pos] & bmask); 88 } 89 90 int 91 bm_firstunset(struct bitmap * bm) 92 { 93 int szmap = (bm->size / 8) + !!(bm->size % 8); 94 int at = 0; 95 int pos = 0; 96 97 while (pos < szmap) { 98 unsigned char bmv = bm->map[pos++]; 99 unsigned char bmask = 1; 100 101 while (bmask & 0xff) { 102 if ((bmv & bmask) == 0) 103 return at; 104 bmask <<= 1; 105 ++at; 106 } 107 } 108 return at; 109 } 110 111 int 112 bm_lastset(struct bitmap * bm) 113 { 114 int szmap = (bm->size / 8) + !!(bm->size % 8); 115 int at = 0; 116 int pos = 0; 117 int ofs = 0; 118 119 while (pos < szmap) { 120 unsigned char bmv = bm->map[pos++]; 121 unsigned char bmask = 1; 122 123 while (bmask & 0xff) { 124 if ((bmv & bmask) != 0) 125 ofs = at; 126 bmask <<= 1; 127 ++at; 128 } 129 } 130 return ofs; 131 } 132