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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  */
  20 #include "cache.h"
  21 #include "ewok.h"
  22
  23 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
  24 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
  25
  26 struct bitmap *bitmap_new(void)
  27 {
  28         struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
  29         bitmap->words = xcalloc(32, sizeof(eword_t));
  30         bitmap->word_alloc = 32;
  31         return bitmap;
  32 }
  33
  34 void bitmap_set(struct bitmap *self, size_t pos)
  35 {
  36         size_t block = EWAH_BLOCK(pos);
  37
  38         if (block >= self->word_alloc) {
  39                 size_t old_size = self->word_alloc;
  40                 self->word_alloc = block * 2;
  41                 REALLOC_ARRAY(self->words, self->word_alloc);
  42                 memset(self->words + old_size, 0x0,
  43                         (self->word_alloc - old_size) * sizeof(eword_t));
  44         }
  45
  46         self->words[block] |= EWAH_MASK(pos);
  47 }
  48
  49 void bitmap_clear(struct bitmap *self, size_t pos)
  50 {
  51         size_t block = EWAH_BLOCK(pos);
  52
  53         if (block < self->word_alloc)
  54                 self->words[block] &= ~EWAH_MASK(pos);
  55 }
  56
  57 int bitmap_get(struct bitmap *self, size_t pos)
  58 {
  59         size_t block = EWAH_BLOCK(pos);
  60         return block < self->word_alloc &&
  61                 (self->words[block] & EWAH_MASK(pos)) != 0;
  62 }
  63
  64 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
  65 {
  66         struct ewah_bitmap *ewah = ewah_new();
  67         size_t i, running_empty_words = 0;
  68         eword_t last_word = 0;
  69
  70         for (i = 0; i < bitmap->word_alloc; ++i) {
  71                 if (bitmap->words[i] == 0) {
  72                         running_empty_words++;
  73                         continue;
  74                 }
  75
  76                 if (last_word != 0)
  77                         ewah_add(ewah, last_word);
  78
  79                 if (running_empty_words > 0) {
  80                         ewah_add_empty_words(ewah, 0, running_empty_words);
  81                         running_empty_words = 0;
  82                 }
  83
  84                 last_word = bitmap->words[i];
  85         }
  86
  87         ewah_add(ewah, last_word);
  88         return ewah;
  89 }
  90
  91 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
  92 {
  93         struct bitmap *bitmap = bitmap_new();
  94         struct ewah_iterator it;
  95         eword_t blowup;
  96         size_t i = 0;
  97
  98         ewah_iterator_init(&it, ewah);
  99
 100         while (ewah_iterator_next(&blowup, &it)) {
 101                 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
 102                 bitmap->words[i++] = blowup;
 103         }
 104
 105         bitmap->word_alloc = i;
 106         return bitmap;
 107 }
 108
 109 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
 110 {
 111         const size_t count = (self->word_alloc < other->word_alloc) ?
 112                 self->word_alloc : other->word_alloc;
 113
 114         size_t i;
 115
 116         for (i = 0; i < count; ++i)
 117                 self->words[i] &= ~other->words[i];
 118 }
 119
 120 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
 121 {
 122         size_t original_size = self->word_alloc;
 123         size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
 124         size_t i = 0;
 125         struct ewah_iterator it;
 126         eword_t word;
 127
 128         if (self->word_alloc < other_final) {
 129                 self->word_alloc = other_final;
 130                 REALLOC_ARRAY(self->words, self->word_alloc);
 131                 memset(self->words + original_size, 0x0,
 132                         (self->word_alloc - original_size) * sizeof(eword_t));
 133         }
 134
 135         ewah_iterator_init(&it, other);
 136
 137         while (ewah_iterator_next(&word, &it))
 138                 self->words[i++] |= word;
 139 }
 140
 141 void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data)
 142 {
 143         size_t pos = 0, i;
 144
 145         for (i = 0; i < self->word_alloc; ++i) {
 146                 eword_t word = self->words[i];
 147                 uint32_t offset;
 148
 149                 if (word == (eword_t)~0) {
 150                         for (offset = 0; offset < BITS_IN_EWORD; ++offset)
 151                                 callback(pos++, data);
 152                 } else {
 153                         for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 154                                 if ((word >> offset) == 0)
 155                                         break;
 156
 157                                 offset += ewah_bit_ctz64(word >> offset);
 158                                 callback(pos + offset, data);
 159                         }
 160                         pos += BITS_IN_EWORD;
 161                 }
 162         }
 163 }
 164
 165 size_t bitmap_popcount(struct bitmap *self)
 166 {
 167         size_t i, count = 0;
 168
 169         for (i = 0; i < self->word_alloc; ++i)
 170                 count += ewah_bit_popcount64(self->words[i]);
 171
 172         return count;
 173 }
 174
 175 int bitmap_equals(struct bitmap *self, struct bitmap *other)
 176 {
 177         struct bitmap *big, *small;
 178         size_t i;
 179
 180         if (self->word_alloc < other->word_alloc) {
 181                 small = self;
 182                 big = other;
 183         } else {
 184                 small = other;
 185                 big = self;
 186         }
 187
 188         for (i = 0; i < small->word_alloc; ++i) {
 189                 if (small->words[i] != big->words[i])
 190                         return 0;
 191         }
 192
 193         for (; i < big->word_alloc; ++i) {
 194                 if (big->words[i] != 0)
 195                         return 0;
 196         }
 197
 198         return 1;
 199 }
 200
 201 void bitmap_reset(struct bitmap *bitmap)
 202 {
 203         memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
 204 }
 205
 206 void bitmap_free(struct bitmap *bitmap)
 207 {
 208         if (bitmap == NULL)
 209                 return;
 210
 211         free(bitmap->words);
 212         free(bitmap);
 213 }