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| 1200 | jermar | 1 | /* |
| 2 | * Copyright (C) 2006 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 1248 | jermar | 29 | /** |
| 30 | * @file bitmap.c |
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| 31 | * @brief Implementation of bitmap ADT. |
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| 32 | * |
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| 33 | * This file implements bitmap ADT and provides functions for |
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| 34 | * setting and clearing ranges of bits. |
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| 35 | */ |
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| 36 | |||
| 1200 | jermar | 37 | #include <adt/bitmap.h> |
| 38 | #include <typedefs.h> |
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| 39 | #include <arch/types.h> |
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| 40 | #include <align.h> |
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| 41 | #include <debug.h> |
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| 1262 | jermar | 42 | #include <macros.h> |
| 1200 | jermar | 43 | |
| 44 | #define ALL_ONES 0xff |
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| 45 | #define ALL_ZEROES 0x00 |
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| 46 | |||
| 47 | /** Initialize bitmap. |
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| 48 | * |
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| 49 | * No portion of the bitmap is set or cleared by this function. |
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| 50 | * |
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| 51 | * @param bitmap Bitmap structure. |
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| 52 | * @param map Address of the memory used to hold the map. |
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| 53 | * @param bits Number of bits stored in bitmap. |
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| 54 | */ |
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| 55 | void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits) |
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| 56 | { |
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| 57 | bitmap->map = map; |
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| 58 | bitmap->bits = bits; |
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| 59 | } |
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| 60 | |||
| 61 | /** Set range of bits. |
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| 62 | * |
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| 63 | * @param bitmap Bitmap structure. |
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| 64 | * @param start Starting bit. |
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| 65 | * @param bits Number of bits to set. |
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| 66 | */ |
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| 67 | void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits) |
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| 68 | { |
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| 1549 | vana | 69 | index_t i=0; |
| 1200 | jermar | 70 | index_t aligned_start; |
| 71 | count_t lub; /* leading unaligned bits */ |
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| 1262 | jermar | 72 | count_t amb; /* aligned middle bits */ |
| 73 | count_t tab; /* trailing aligned bits */ |
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| 1200 | jermar | 74 | |
| 75 | ASSERT(start + bits <= bitmap->bits); |
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| 76 | |||
| 77 | aligned_start = ALIGN_UP(start, 8); |
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| 1262 | jermar | 78 | lub = min(aligned_start - start, bits); |
| 79 | amb = bits > lub ? bits - lub : 0; |
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| 80 | tab = amb % 8; |
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| 1200 | jermar | 81 | |
| 1549 | vana | 82 | if ( start + bits < aligned_start ) { |
| 83 | /* |
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| 84 | * Set bits in the middle of byte |
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| 85 | */ |
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| 86 | bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7); |
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| 87 | return; |
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| 88 | } |
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| 89 | |||
| 1200 | jermar | 90 | if (lub) { |
| 91 | /* |
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| 92 | * Make sure to set any leading unaligned bits. |
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| 93 | */ |
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| 94 | bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1); |
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| 95 | } |
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| 1262 | jermar | 96 | for (i = 0; i < amb / 8; i++) { |
| 1200 | jermar | 97 | /* |
| 98 | * The middle bits can be set byte by byte. |
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| 99 | */ |
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| 100 | bitmap->map[aligned_start / 8 + i] = ALL_ONES; |
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| 101 | } |
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| 1262 | jermar | 102 | if (tab) { |
| 1200 | jermar | 103 | /* |
| 1262 | jermar | 104 | * Make sure to set any trailing aligned bits. |
| 1200 | jermar | 105 | */ |
| 1262 | jermar | 106 | bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1; |
| 1200 | jermar | 107 | } |
| 108 | |||
| 109 | } |
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| 110 | |||
| 111 | /** Clear range of bits. |
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| 112 | * |
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| 113 | * @param bitmap Bitmap structure. |
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| 114 | * @param start Starting bit. |
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| 115 | * @param bits Number of bits to clear. |
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| 116 | */ |
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| 117 | void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits) |
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| 118 | { |
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| 1549 | vana | 119 | index_t i=0; |
| 1200 | jermar | 120 | index_t aligned_start; |
| 121 | count_t lub; /* leading unaligned bits */ |
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| 1262 | jermar | 122 | count_t amb; /* aligned middle bits */ |
| 123 | count_t tab; /* trailing aligned bits */ |
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| 1200 | jermar | 124 | |
| 125 | ASSERT(start + bits <= bitmap->bits); |
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| 126 | |||
| 127 | aligned_start = ALIGN_UP(start, 8); |
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| 1262 | jermar | 128 | lub = min(aligned_start - start, bits); |
| 129 | amb = bits > lub ? bits - lub : 0; |
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| 130 | tab = amb % 8; |
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| 131 | |||
| 1549 | vana | 132 | if ( start + bits < aligned_start ) |
| 133 | { |
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| 134 | /* |
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| 135 | * Set bits in the middle of byte |
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| 136 | */ |
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| 137 | bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7)); |
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| 138 | return; |
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| 139 | } |
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| 140 | |||
| 141 | |||
| 1200 | jermar | 142 | if (lub) { |
| 143 | /* |
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| 144 | * Make sure to clear any leading unaligned bits. |
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| 145 | */ |
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| 146 | bitmap->map[start / 8] &= (1 << (8 - lub)) - 1; |
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| 147 | } |
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| 1262 | jermar | 148 | for (i = 0; i < amb / 8; i++) { |
| 1200 | jermar | 149 | /* |
| 150 | * The middle bits can be cleared byte by byte. |
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| 151 | */ |
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| 152 | bitmap->map[aligned_start / 8 + i] = ALL_ZEROES; |
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| 153 | } |
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| 1262 | jermar | 154 | if (tab) { |
| 1200 | jermar | 155 | /* |
| 1262 | jermar | 156 | * Make sure to clear any trailing aligned bits. |
| 1200 | jermar | 157 | */ |
| 1262 | jermar | 158 | bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1); |
| 1200 | jermar | 159 | } |
| 1262 | jermar | 160 | |
| 1200 | jermar | 161 | } |
| 162 | |||
| 163 | /** Copy portion of one bitmap into another bitmap. |
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| 164 | * |
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| 165 | * @param dst Destination bitmap. |
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| 166 | * @param src Source bitmap. |
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| 167 | * @param bits Number of bits to copy. |
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| 168 | */ |
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| 169 | void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits) |
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| 170 | { |
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| 171 | index_t i; |
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| 172 | |||
| 173 | ASSERT(bits <= dst->bits); |
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| 174 | ASSERT(bits <= src->bits); |
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| 175 | |||
| 176 | for (i = 0; i < bits / 8; i++) |
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| 177 | dst->map[i] = src->map[i]; |
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| 178 | |||
| 179 | if (bits % 8) { |
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| 180 | bitmap_clear_range(dst, i * 8, bits % 8); |
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| 181 | dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1); |
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| 182 | } |
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| 183 | } |