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