ewah/bitmap.c

   1 /**
   2  * Copyright 2013, GitHub, Inc
   3  * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
   4  *      David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include "cache.h"
  20 #include "ewok.h"
  21
  22 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
  23 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
  24
  25 struct bitmap *bitmap_word_alloc(size_t word_alloc)
  26 {
  27         struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
  28         bitmap->words = xcalloc(word_alloc, sizeof(eword_t));
  29         bitmap->word_alloc = word_alloc;
  30         return bitmap;
  31 }
  32
  33 struct bitmap *bitmap_new(void)
  34 {
  35         return bitmap_word_alloc(32);
  36 }
  37
  38 void bitmap_set(struct bitmap *self, size_t pos)
  39 {
  40         size_t block = EWAH_BLOCK(pos);
  41
  42         if (block >= self->word_alloc) {
  43                 size_t old_size = self->word_alloc;
  44                 self->word_alloc = block ? block * 2 : 1;
  45                 REALLOC_ARRAY(self->words, self->word_alloc);
  46                 memset(self->words + old_size, 0x0,
  47                         (self->word_alloc - old_size) * sizeof(eword_t));
  48         }
  49
  50         self->words[block] |= EWAH_MASK(pos);
  51 }
  52
  53 void bitmap_unset(struct bitmap *self, size_t pos)
  54 {
  55         size_t block = EWAH_BLOCK(pos);
  56
  57         if (block < self->word_alloc)
  58                 self->words[block] &= ~EWAH_MASK(pos);
  59 }
  60
  61 int bitmap_get(struct bitmap *self, size_t pos)
  62 {
  63         size_t block = EWAH_BLOCK(pos);
  64         return block < self->word_alloc &&
  65                 (self->words[block] & EWAH_MASK(pos)) != 0;
  66 }
  67
  68 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
  69 {
  70         struct ewah_bitmap *ewah = ewah_new();
  71         size_t i, running_empty_words = 0;
  72         eword_t last_word = 0;
  73
  74         for (i = 0; i < bitmap->word_alloc; ++i) {
  75                 if (bitmap->words[i] == 0) {
  76                         running_empty_words++;
  77                         continue;
  78                 }
  79
  80                 if (last_word != 0)
  81                         ewah_add(ewah, last_word);
  82
  83                 if (running_empty_words > 0) {
  84                         ewah_add_empty_words(ewah, 0, running_empty_words);
  85                         running_empty_words = 0;
  86                 }
  87
  88                 last_word = bitmap->words[i];
  89         }
  90
  91         ewah_add(ewah, last_word);
  92         return ewah;
  93 }
  94
  95 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
  96 {
  97         struct bitmap *bitmap = bitmap_new();
  98         struct ewah_iterator it;
  99         eword_t blowup;
 100         size_t i = 0;
 101
 102         ewah_iterator_init(&it, ewah);
 103
 104         while (ewah_iterator_next(&blowup, &it)) {
 105                 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
 106                 bitmap->words[i++] = blowup;
 107         }
 108
 109         bitmap->word_alloc = i;
 110         return bitmap;
 111 }
 112
 113 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
 114 {
 115         const size_t count = (self->word_alloc < other->word_alloc) ?
 116                 self->word_alloc : other->word_alloc;
 117
 118         size_t i;
 119
 120         for (i = 0; i < count; ++i)
 121                 self->words[i] &= ~other->words[i];
 122 }
 123
 124 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
 125 {
 126         size_t original_size = self->word_alloc;
 127         size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
 128         size_t i = 0;
 129         struct ewah_iterator it;
 130         eword_t word;
 131
 132         if (self->word_alloc < other_final) {
 133                 self->word_alloc = other_final;
 134                 REALLOC_ARRAY(self->words, self->word_alloc);
 135                 memset(self->words + original_size, 0x0,
 136                         (self->word_alloc - original_size) * sizeof(eword_t));
 137         }
 138
 139         ewah_iterator_init(&it, other);
 140
 141         while (ewah_iterator_next(&word, &it))
 142                 self->words[i++] |= word;
 143 }
 144
 145 size_t bitmap_popcount(struct bitmap *self)
 146 {
 147         size_t i, count = 0;
 148
 149         for (i = 0; i < self->word_alloc; ++i)
 150                 count += ewah_bit_popcount64(self->words[i]);
 151
 152         return count;
 153 }
 154
 155 int bitmap_equals(struct bitmap *self, struct bitmap *other)
 156 {
 157         struct bitmap *big, *small;
 158         size_t i;
 159
 160         if (self->word_alloc < other->word_alloc) {
 161                 small = self;
 162                 big = other;
 163         } else {
 164                 small = other;
 165                 big = self;
 166         }
 167
 168         for (i = 0; i < small->word_alloc; ++i) {
 169                 if (small->words[i] != big->words[i])
 170                         return 0;
 171         }
 172
 173         for (; i < big->word_alloc; ++i) {
 174                 if (big->words[i] != 0)
 175                         return 0;
 176         }
 177
 178         return 1;
 179 }
 180
 181 void bitmap_reset(struct bitmap *bitmap)
 182 {
 183         memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
 184 }
 185
 186 void bitmap_free(struct bitmap *bitmap)
 187 {
 188         if (bitmap == NULL)
 189                 return;
 190
 191         free(bitmap->words);
 192         free(bitmap);
 193 }