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