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 * $Id$ 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 if (bm->map) 51 free(bm->map); 52 } 53 54 static void 55 bm_getmask(int *pos, unsigned char *bmask) 56 { 57 *bmask = (unsigned char) (1 << (*pos % 8)); 58 *pos /= 8; 59 } 60 61 void 62 bm_setbit(struct bitmap * bm, int pos) 63 { 64 unsigned char bmask; 65 66 bm_getmask(&pos, &bmask); 67 bm->map[pos] |= bmask; 68 } 69 70 void 71 bm_clrbit(struct bitmap * bm, int pos) 72 { 73 unsigned char bmask; 74 75 bm_getmask(&pos, &bmask); 76 bm->map[pos] &= ~bmask; 77 } 78 79 int 80 bm_isset(struct bitmap * bm, int pos) 81 { 82 unsigned char bmask; 83 84 bm_getmask(&pos, &bmask); 85 return !!(bm->map[pos] & bmask); 86 } 87 88 int 89 bm_firstunset(struct bitmap * bm) 90 { 91 int szmap = (bm->size / 8) + !!(bm->size % 8); 92 int at = 0; 93 int pos = 0; 94 95 while (pos < szmap) { 96 unsigned char bmv = bm->map[pos++]; 97 unsigned char bmask = 1; 98 99 while (bmask & 0xff) { 100 if ((bmv & bmask) == 0) 101 return at; 102 bmask <<= 1; 103 ++at; 104 } 105 } 106 return at; 107 } 108 109 int 110 bm_lastset(struct bitmap * bm) 111 { 112 int szmap = (bm->size / 8) + !!(bm->size % 8); 113 int at = 0; 114 int pos = 0; 115 int ofs = 0; 116 117 while (pos < szmap) { 118 unsigned char bmv = bm->map[pos++]; 119 unsigned char bmask = 1; 120 121 while (bmask & 0xff) { 122 if ((bmv & bmask) != 0) 123 ofs = at; 124 bmask <<= 1; 125 ++at; 126 } 127 } 128 return ofs; 129 } 130