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: src/usr.sbin/pw/bitmap.c,v 1.5 1999/08/28 01:19:15 peter Exp $"; 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 if (bm->map) 54 free(bm->map); 55 } 56 57 static void 58 bm_getmask(int *pos, unsigned char *bmask) 59 { 60 *bmask = (unsigned char) (1 << (*pos % 8)); 61 *pos /= 8; 62 } 63 64 void 65 bm_setbit(struct bitmap * bm, int pos) 66 { 67 unsigned char bmask; 68 69 bm_getmask(&pos, &bmask); 70 bm->map[pos] |= bmask; 71 } 72 73 void 74 bm_clrbit(struct bitmap * bm, int pos) 75 { 76 unsigned char bmask; 77 78 bm_getmask(&pos, &bmask); 79 bm->map[pos] &= ~bmask; 80 } 81 82 int 83 bm_isset(struct bitmap * bm, int pos) 84 { 85 unsigned char bmask; 86 87 bm_getmask(&pos, &bmask); 88 return !!(bm->map[pos] & bmask); 89 } 90 91 int 92 bm_firstunset(struct bitmap * bm) 93 { 94 int szmap = (bm->size / 8) + !!(bm->size % 8); 95 int at = 0; 96 int pos = 0; 97 98 while (pos < szmap) { 99 unsigned char bmv = bm->map[pos++]; 100 unsigned char bmask = 1; 101 102 while (bmask & 0xff) { 103 if ((bmv & bmask) == 0) 104 return at; 105 bmask <<= 1; 106 ++at; 107 } 108 } 109 return at; 110 } 111 112 int 113 bm_lastset(struct bitmap * bm) 114 { 115 int szmap = (bm->size / 8) + !!(bm->size % 8); 116 int at = 0; 117 int pos = 0; 118 int ofs = 0; 119 120 while (pos < szmap) { 121 unsigned char bmv = bm->map[pos++]; 122 unsigned char bmask = 1; 123 124 while (bmask & 0xff) { 125 if ((bmv & bmask) != 0) 126 ofs = at; 127 bmask <<= 1; 128 ++at; 129 } 130 } 131 return ofs; 132 } 133