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_new(void)
  26 {
  27         struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
  28         bitmap->words = xcalloc(32, sizeof(eword_t));
  29         bitmap->word_alloc = 32;
  30         return bitmap;
  31 }
  32
  33 void bitmap_set(struct bitmap *self, size_t pos)
  34 {
  35         size_t block = EWAH_BLOCK(pos);
  36
  37         if (block >= self->word_alloc) {
  38                 size_t old_size = self->word_alloc;
  39                 self->word_alloc = block * 2;
  40                 REALLOC_ARRAY(self->words, self->word_alloc);
  41                 memset(self->words + old_size, 0x0,
  42                         (self->word_alloc - old_size) * sizeof(eword_t));
  43         }
  44
  45         self->words[block] |= EWAH_MASK(pos);
  46 }
  47
  48 void bitmap_unset(struct bitmap *self, size_t pos)
  49 {
  50         size_t block = EWAH_BLOCK(pos);
  51
  52         if (block < self->word_alloc)
  53                 self->words[block] &= ~EWAH_MASK(pos);
  54 }
  55
  56 int bitmap_get(struct bitmap *self, size_t pos)
  57 {
  58         size_t block = EWAH_BLOCK(pos);
  59         return block < self->word_alloc &&
  60                 (self->words[block] & EWAH_MASK(pos)) != 0;
  61 }
  62
  63 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
  64 {
  65         struct ewah_bitmap *ewah = ewah_new();
  66         size_t i, running_empty_words = 0;
  67         eword_t last_word = 0;
  68
  69         for (i = 0; i < bitmap->word_alloc; ++i) {
  70                 if (bitmap->words[i] == 0) {
  71                         running_empty_words++;
  72                         continue;
  73                 }
  74
  75                 if (last_word != 0)
  76                         ewah_add(ewah, last_word);
  77
  78                 if (running_empty_words > 0) {
  79                         ewah_add_empty_words(ewah, 0, running_empty_words);
  80                         running_empty_words = 0;
  81                 }
  82
  83                 last_word = bitmap->words[i];
  84         }
  85
  86         ewah_add(ewah, last_word);
  87         return ewah;
  88 }
  89
  90 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
  91 {
  92         struct bitmap *bitmap = bitmap_new();
  93         struct ewah_iterator it;
  94         eword_t blowup;
  95         size_t i = 0;
  96
  97         ewah_iterator_init(&it, ewah);
  98
  99         while (ewah_iterator_next(&blowup, &it)) {
 100                 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
 101                 bitmap->words[i++] = blowup;
 102         }
 103
 104         bitmap->word_alloc = i;
 105         return bitmap;
 106 }
 107
 108 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
 109 {
 110         const size_t count = (self->word_alloc < other->word_alloc) ?
 111                 self->word_alloc : other->word_alloc;
 112
 113         size_t i;
 114
 115         for (i = 0; i < count; ++i)
 116                 self->words[i] &= ~other->words[i];
 117 }
 118
 119 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
 120 {
 121         size_t original_size = self->word_alloc;
 122         size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
 123         size_t i = 0;
 124         struct ewah_iterator it;
 125         eword_t word;
 126
 127         if (self->word_alloc < other_final) {
 128                 self->word_alloc = other_final;
 129                 REALLOC_ARRAY(self->words, self->word_alloc);
 130                 memset(self->words + original_size, 0x0,
 131                         (self->word_alloc - original_size) * sizeof(eword_t));
 132         }
 133
 134         ewah_iterator_init(&it, other);
 135
 136         while (ewah_iterator_next(&word, &it))
 137                 self->words[i++] |= word;
 138 }
 139
 140 size_t bitmap_popcount(struct bitmap *self)
 141 {
 142         size_t i, count = 0;
 143
 144         for (i = 0; i < self->word_alloc; ++i)
 145                 count += ewah_bit_popcount64(self->words[i]);
 146
 147         return count;
 148 }
 149
 150 int bitmap_equals(struct bitmap *self, struct bitmap *other)
 151 {
 152         struct bitmap *big, *small;
 153         size_t i;
 154
 155         if (self->word_alloc < other->word_alloc) {
 156                 small = self;
 157                 big = other;
 158         } else {
 159                 small = other;
 160                 big = self;
 161         }
 162
 163         for (i = 0; i < small->word_alloc; ++i) {
 164                 if (small->words[i] != big->words[i])
 165                         return 0;
 166         }
 167
 168         for (; i < big->word_alloc; ++i) {
 169                 if (big->words[i] != 0)
 170                         return 0;
 171         }
 172
 173         return 1;
 174 }
 175
 176 void bitmap_reset(struct bitmap *bitmap)
 177 {
 178         memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
 179 }
 180
 181 void bitmap_free(struct bitmap *bitmap)
 182 {
 183         if (bitmap == NULL)
 184                 return;
 185
 186         free(bitmap->words);
 187         free(bitmap);
 188 }