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 "git-compat-util.h"
  20 #include "alloc.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_word_alloc(size_t word_alloc)
  27 {
  28         struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
  29         CALLOC_ARRAY(bitmap->words, word_alloc);
  30         bitmap->word_alloc = word_alloc;
  31         return bitmap;
  32 }
  33
  34 struct bitmap *bitmap_new(void)
  35 {
  36         return bitmap_word_alloc(32);
  37 }
  38
  39 struct bitmap *bitmap_dup(const struct bitmap *src)
  40 {
  41         struct bitmap *dst = bitmap_word_alloc(src->word_alloc);
  42         COPY_ARRAY(dst->words, src->words, src->word_alloc);
  43         return dst;
  44 }
  45
  46 static void bitmap_grow(struct bitmap *self, size_t word_alloc)
  47 {
  48         size_t old_size = self->word_alloc;
  49         ALLOC_GROW(self->words, word_alloc, self->word_alloc);
  50         memset(self->words + old_size, 0x0,
  51                (self->word_alloc - old_size) * sizeof(eword_t));
  52 }
  53
  54 void bitmap_set(struct bitmap *self, size_t pos)
  55 {
  56         size_t block = EWAH_BLOCK(pos);
  57
  58         bitmap_grow(self, block + 1);
  59         self->words[block] |= EWAH_MASK(pos);
  60 }
  61
  62 void bitmap_unset(struct bitmap *self, size_t pos)
  63 {
  64         size_t block = EWAH_BLOCK(pos);
  65
  66         if (block < self->word_alloc)
  67                 self->words[block] &= ~EWAH_MASK(pos);
  68 }
  69
  70 int bitmap_get(struct bitmap *self, size_t pos)
  71 {
  72         size_t block = EWAH_BLOCK(pos);
  73         return block < self->word_alloc &&
  74                 (self->words[block] & EWAH_MASK(pos)) != 0;
  75 }
  76
  77 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
  78 {
  79         struct ewah_bitmap *ewah = ewah_new();
  80         size_t i, running_empty_words = 0;
  81         eword_t last_word = 0;
  82
  83         for (i = 0; i < bitmap->word_alloc; ++i) {
  84                 if (bitmap->words[i] == 0) {
  85                         running_empty_words++;
  86                         continue;
  87                 }
  88
  89                 if (last_word != 0)
  90                         ewah_add(ewah, last_word);
  91
  92                 if (running_empty_words > 0) {
  93                         ewah_add_empty_words(ewah, 0, running_empty_words);
  94                         running_empty_words = 0;
  95                 }
  96
  97                 last_word = bitmap->words[i];
  98         }
  99
 100         ewah_add(ewah, last_word);
 101         return ewah;
 102 }
 103
 104 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
 105 {
 106         struct bitmap *bitmap = bitmap_new();
 107         struct ewah_iterator it;
 108         eword_t blowup;
 109         size_t i = 0;
 110
 111         ewah_iterator_init(&it, ewah);
 112
 113         while (ewah_iterator_next(&blowup, &it)) {
 114                 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
 115                 bitmap->words[i++] = blowup;
 116         }
 117
 118         bitmap->word_alloc = i;
 119         return bitmap;
 120 }
 121
 122 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
 123 {
 124         const size_t count = (self->word_alloc < other->word_alloc) ?
 125                 self->word_alloc : other->word_alloc;
 126
 127         size_t i;
 128
 129         for (i = 0; i < count; ++i)
 130                 self->words[i] &= ~other->words[i];
 131 }
 132
 133 void bitmap_or(struct bitmap *self, const struct bitmap *other)
 134 {
 135         size_t i;
 136
 137         bitmap_grow(self, other->word_alloc);
 138         for (i = 0; i < other->word_alloc; i++)
 139                 self->words[i] |= other->words[i];
 140 }
 141
 142 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
 143 {
 144         size_t original_size = self->word_alloc;
 145         size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
 146         size_t i = 0;
 147         struct ewah_iterator it;
 148         eword_t word;
 149
 150         if (self->word_alloc < other_final) {
 151                 self->word_alloc = other_final;
 152                 REALLOC_ARRAY(self->words, self->word_alloc);
 153                 memset(self->words + original_size, 0x0,
 154                         (self->word_alloc - original_size) * sizeof(eword_t));
 155         }
 156
 157         ewah_iterator_init(&it, other);
 158
 159         while (ewah_iterator_next(&word, &it))
 160                 self->words[i++] |= word;
 161 }
 162
 163 size_t bitmap_popcount(struct bitmap *self)
 164 {
 165         size_t i, count = 0;
 166
 167         for (i = 0; i < self->word_alloc; ++i)
 168                 count += ewah_bit_popcount64(self->words[i]);
 169
 170         return count;
 171 }
 172
 173 int bitmap_equals(struct bitmap *self, struct bitmap *other)
 174 {
 175         struct bitmap *big, *small;
 176         size_t i;
 177
 178         if (self->word_alloc < other->word_alloc) {
 179                 small = self;
 180                 big = other;
 181         } else {
 182                 small = other;
 183                 big = self;
 184         }
 185
 186         for (i = 0; i < small->word_alloc; ++i) {
 187                 if (small->words[i] != big->words[i])
 188                         return 0;
 189         }
 190
 191         for (; i < big->word_alloc; ++i) {
 192                 if (big->words[i] != 0)
 193                         return 0;
 194         }
 195
 196         return 1;
 197 }
 198
 199 int bitmap_is_subset(struct bitmap *self, struct bitmap *other)
 200 {
 201         size_t common_size, i;
 202
 203         if (self->word_alloc < other->word_alloc)
 204                 common_size = self->word_alloc;
 205         else {
 206                 common_size = other->word_alloc;
 207                 for (i = common_size; i < self->word_alloc; i++) {
 208                         if (self->words[i])
 209                                 return 1;
 210                 }
 211         }
 212
 213         for (i = 0; i < common_size; i++) {
 214                 if (self->words[i] & ~other->words[i])
 215                         return 1;
 216         }
 217         return 0;
 218 }
 219
 220 void bitmap_free(struct bitmap *bitmap)
 221 {
 222         if (!bitmap)
 223                 return;
 224
 225         free(bitmap->words);
 226         free(bitmap);
 227 }