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 "git-compat-util.h"
  21 #include "ewok.h"
  22
  23 #define MASK(x) ((eword_t)1 << (x % BITS_IN_WORD))
  24 #define BLOCK(x) (x / BITS_IN_WORD)
  25
  26 struct bitmap *bitmap_new(void)
  27 {
  28         struct bitmap *bitmap = ewah_malloc(sizeof(struct bitmap));
  29         bitmap->words = ewah_calloc(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 = BLOCK(pos);
  37
  38         if (block >= self->word_alloc) {
  39                 size_t old_size = self->word_alloc;
  40                 self->word_alloc = block * 2;
  41                 self->words = ewah_realloc(self->words,
  42                         self->word_alloc * sizeof(eword_t));
  43
  44                 memset(self->words + old_size, 0x0,
  45                         (self->word_alloc - old_size) * sizeof(eword_t));
  46         }
  47
  48         self->words[block] |= MASK(pos);
  49 }
  50
  51 void bitmap_clear(struct bitmap *self, size_t pos)
  52 {
  53         size_t block = BLOCK(pos);
  54
  55         if (block < self->word_alloc)
  56                 self->words[block] &= ~MASK(pos);
  57 }
  58
  59 int bitmap_get(struct bitmap *self, size_t pos)
  60 {
  61         size_t block = BLOCK(pos);
  62         return block < self->word_alloc &&
  63                 (self->words[block] & MASK(pos)) != 0;
  64 }
  65
  66 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
  67 {
  68         struct ewah_bitmap *ewah = ewah_new();
  69         size_t i, running_empty_words = 0;
  70         eword_t last_word = 0;
  71
  72         for (i = 0; i < bitmap->word_alloc; ++i) {
  73                 if (bitmap->words[i] == 0) {
  74                         running_empty_words++;
  75                         continue;
  76                 }
  77
  78                 if (last_word != 0)
  79                         ewah_add(ewah, last_word);
  80
  81                 if (running_empty_words > 0) {
  82                         ewah_add_empty_words(ewah, 0, running_empty_words);
  83                         running_empty_words = 0;
  84                 }
  85
  86                 last_word = bitmap->words[i];
  87         }
  88
  89         ewah_add(ewah, last_word);
  90         return ewah;
  91 }
  92
  93 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
  94 {
  95         struct bitmap *bitmap = bitmap_new();
  96         struct ewah_iterator it;
  97         eword_t blowup;
  98         size_t i = 0;
  99
 100         ewah_iterator_init(&it, ewah);
 101
 102         while (ewah_iterator_next(&blowup, &it)) {
 103                 if (i >= bitmap->word_alloc) {
 104                         bitmap->word_alloc *= 1.5;
 105                         bitmap->words = ewah_realloc(
 106                                 bitmap->words, bitmap->word_alloc * sizeof(eword_t));
 107                 }
 108
 109                 bitmap->words[i++] = blowup;
 110         }
 111
 112         bitmap->word_alloc = i;
 113         return bitmap;
 114 }
 115
 116 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
 117 {
 118         const size_t count = (self->word_alloc < other->word_alloc) ?
 119                 self->word_alloc : other->word_alloc;
 120
 121         size_t i;
 122
 123         for (i = 0; i < count; ++i)
 124                 self->words[i] &= ~other->words[i];
 125 }
 126
 127 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
 128 {
 129         size_t original_size = self->word_alloc;
 130         size_t other_final = (other->bit_size / BITS_IN_WORD) + 1;
 131         size_t i = 0;
 132         struct ewah_iterator it;
 133         eword_t word;
 134
 135         if (self->word_alloc < other_final) {
 136                 self->word_alloc = other_final;
 137                 self->words = ewah_realloc(self->words,
 138                         self->word_alloc * sizeof(eword_t));
 139                 memset(self->words + original_size, 0x0,
 140                         (self->word_alloc - original_size) * sizeof(eword_t));
 141         }
 142
 143         ewah_iterator_init(&it, other);
 144
 145         while (ewah_iterator_next(&word, &it))
 146                 self->words[i++] |= word;
 147 }
 148
 149 void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data)
 150 {
 151         size_t pos = 0, i;
 152
 153         for (i = 0; i < self->word_alloc; ++i) {
 154                 eword_t word = self->words[i];
 155                 uint32_t offset;
 156
 157                 if (word == (eword_t)~0) {
 158                         for (offset = 0; offset < BITS_IN_WORD; ++offset)
 159                                 callback(pos++, data);
 160                 } else {
 161                         for (offset = 0; offset < BITS_IN_WORD; ++offset) {
 162                                 if ((word >> offset) == 0)
 163                                         break;
 164
 165                                 offset += ewah_bit_ctz64(word >> offset);
 166                                 callback(pos + offset, data);
 167                         }
 168                         pos += BITS_IN_WORD;
 169                 }
 170         }
 171 }
 172
 173 size_t bitmap_popcount(struct bitmap *self)
 174 {
 175         size_t i, count = 0;
 176
 177         for (i = 0; i < self->word_alloc; ++i)
 178                 count += ewah_bit_popcount64(self->words[i]);
 179
 180         return count;
 181 }
 182
 183 int bitmap_equals(struct bitmap *self, struct bitmap *other)
 184 {
 185         struct bitmap *big, *small;
 186         size_t i;
 187
 188         if (self->word_alloc < other->word_alloc) {
 189                 small = self;
 190                 big = other;
 191         } else {
 192                 small = other;
 193                 big = self;
 194         }
 195
 196         for (i = 0; i < small->word_alloc; ++i) {
 197                 if (small->words[i] != big->words[i])
 198                         return 0;
 199         }
 200
 201         for (; i < big->word_alloc; ++i) {
 202                 if (big->words[i] != 0)
 203                         return 0;
 204         }
 205
 206         return 1;
 207 }
 208
 209 void bitmap_reset(struct bitmap *bitmap)
 210 {
 211         memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
 212 }
 213
 214 void bitmap_free(struct bitmap *bitmap)
 215 {
 216         if (bitmap == NULL)
 217                 return;
 218
 219         free(bitmap->words);
 220         free(bitmap);
 221 }