| 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 "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 | CALLOC_ARRAY(bitmap->words, word_alloc); |
| 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 | struct bitmap *bitmap_dup(const struct bitmap *src) |
| 39 | { |
| 40 | struct bitmap *dst = bitmap_word_alloc(src->word_alloc); |
| 41 | COPY_ARRAY(dst->words, src->words, src->word_alloc); |
| 42 | return dst; |
| 43 | } |
| 44 | |
| 45 | static void bitmap_grow(struct bitmap *self, size_t word_alloc) |
| 46 | { |
| 47 | size_t old_size = self->word_alloc; |
| 48 | ALLOC_GROW(self->words, word_alloc, self->word_alloc); |
| 49 | MEMZERO_ARRAY(self->words + old_size, self->word_alloc - old_size); |
| 50 | } |
| 51 | |
| 52 | void bitmap_set(struct bitmap *self, size_t pos) |
| 53 | { |
| 54 | size_t block = EWAH_BLOCK(pos); |
| 55 | |
| 56 | bitmap_grow(self, block + 1); |
| 57 | self->words[block] |= EWAH_MASK(pos); |
| 58 | } |
| 59 | |
| 60 | void bitmap_unset(struct bitmap *self, size_t pos) |
| 61 | { |
| 62 | size_t block = EWAH_BLOCK(pos); |
| 63 | |
| 64 | if (block < self->word_alloc) |
| 65 | self->words[block] &= ~EWAH_MASK(pos); |
| 66 | } |
| 67 | |
| 68 | int bitmap_get(struct bitmap *self, size_t pos) |
| 69 | { |
| 70 | size_t block = EWAH_BLOCK(pos); |
| 71 | return block < self->word_alloc && |
| 72 | (self->words[block] & EWAH_MASK(pos)) != 0; |
| 73 | } |
| 74 | |
| 75 | struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap) |
| 76 | { |
| 77 | struct ewah_bitmap *ewah = ewah_new(); |
| 78 | size_t i, running_empty_words = 0; |
| 79 | eword_t last_word = 0; |
| 80 | |
| 81 | for (i = 0; i < bitmap->word_alloc; ++i) { |
| 82 | if (bitmap->words[i] == 0) { |
| 83 | running_empty_words++; |
| 84 | continue; |
| 85 | } |
| 86 | |
| 87 | if (last_word != 0) |
| 88 | ewah_add(ewah, last_word); |
| 89 | |
| 90 | if (running_empty_words > 0) { |
| 91 | ewah_add_empty_words(ewah, 0, running_empty_words); |
| 92 | running_empty_words = 0; |
| 93 | } |
| 94 | |
| 95 | last_word = bitmap->words[i]; |
| 96 | } |
| 97 | |
| 98 | ewah_add(ewah, last_word); |
| 99 | return ewah; |
| 100 | } |
| 101 | |
| 102 | struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah) |
| 103 | { |
| 104 | struct bitmap *bitmap = bitmap_new(); |
| 105 | struct ewah_iterator it; |
| 106 | eword_t blowup; |
| 107 | size_t i = 0; |
| 108 | |
| 109 | ewah_iterator_init(&it, ewah); |
| 110 | |
| 111 | while (ewah_iterator_next(&blowup, &it)) { |
| 112 | ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc); |
| 113 | bitmap->words[i++] = blowup; |
| 114 | } |
| 115 | |
| 116 | bitmap->word_alloc = i; |
| 117 | return bitmap; |
| 118 | } |
| 119 | |
| 120 | void bitmap_and_not(struct bitmap *self, struct bitmap *other) |
| 121 | { |
| 122 | const size_t count = (self->word_alloc < other->word_alloc) ? |
| 123 | self->word_alloc : other->word_alloc; |
| 124 | |
| 125 | size_t i; |
| 126 | |
| 127 | for (i = 0; i < count; ++i) |
| 128 | self->words[i] &= ~other->words[i]; |
| 129 | } |
| 130 | |
| 131 | void bitmap_or(struct bitmap *self, const struct bitmap *other) |
| 132 | { |
| 133 | size_t i; |
| 134 | |
| 135 | bitmap_grow(self, other->word_alloc); |
| 136 | for (i = 0; i < other->word_alloc; i++) |
| 137 | self->words[i] |= other->words[i]; |
| 138 | } |
| 139 | |
| 140 | int ewah_bitmap_is_subset(struct ewah_bitmap *self, struct bitmap *other) |
| 141 | { |
| 142 | struct ewah_iterator it; |
| 143 | eword_t word; |
| 144 | size_t i; |
| 145 | |
| 146 | ewah_iterator_init(&it, self); |
| 147 | |
| 148 | for (i = 0; i < other->word_alloc; i++) { |
| 149 | if (!ewah_iterator_next(&word, &it)) { |
| 150 | /* |
| 151 | * If we reached the end of `self`, and haven't |
| 152 | * rejected `self` as a possible subset of |
| 153 | * `other` yet, then we are done and `self` is |
| 154 | * indeed a subset of `other`. |
| 155 | */ |
| 156 | return 1; |
| 157 | } |
| 158 | if (word & ~other->words[i]) { |
| 159 | /* |
| 160 | * Otherwise, compare the next two pairs of |
| 161 | * words. If the word from `self` has bit(s) not |
| 162 | * in the word from `other`, `self` is not a |
| 163 | * subset of `other`. |
| 164 | */ |
| 165 | return 0; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * If we got to this point, there may be zero or more words |
| 171 | * remaining in `self`, with no remaining words left in `other`. |
| 172 | * If there are any bits set in the remaining word(s) in `self`, |
| 173 | * then `self` is not a subset of `other`. |
| 174 | */ |
| 175 | while (ewah_iterator_next(&word, &it)) |
| 176 | if (word) |
| 177 | return 0; |
| 178 | |
| 179 | /* `self` is definitely a subset of `other` */ |
| 180 | return 1; |
| 181 | } |
| 182 | |
| 183 | void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other) |
| 184 | { |
| 185 | size_t original_size = self->word_alloc; |
| 186 | size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1; |
| 187 | size_t i = 0; |
| 188 | struct ewah_iterator it; |
| 189 | eword_t word; |
| 190 | |
| 191 | if (self->word_alloc < other_final) { |
| 192 | self->word_alloc = other_final; |
| 193 | REALLOC_ARRAY(self->words, self->word_alloc); |
| 194 | MEMZERO_ARRAY(self->words + original_size, |
| 195 | self->word_alloc - original_size); |
| 196 | } |
| 197 | |
| 198 | ewah_iterator_init(&it, other); |
| 199 | |
| 200 | while (ewah_iterator_next(&word, &it)) |
| 201 | self->words[i++] |= word; |
| 202 | } |
| 203 | |
| 204 | size_t bitmap_popcount(struct bitmap *self) |
| 205 | { |
| 206 | size_t i, count = 0; |
| 207 | |
| 208 | for (i = 0; i < self->word_alloc; ++i) |
| 209 | count += ewah_bit_popcount64(self->words[i]); |
| 210 | |
| 211 | return count; |
| 212 | } |
| 213 | |
| 214 | size_t ewah_bitmap_popcount(struct ewah_bitmap *self) |
| 215 | { |
| 216 | struct ewah_iterator it; |
| 217 | eword_t word; |
| 218 | size_t count = 0; |
| 219 | |
| 220 | ewah_iterator_init(&it, self); |
| 221 | |
| 222 | while (ewah_iterator_next(&word, &it)) |
| 223 | count += ewah_bit_popcount64(word); |
| 224 | |
| 225 | return count; |
| 226 | } |
| 227 | |
| 228 | int bitmap_is_empty(struct bitmap *self) |
| 229 | { |
| 230 | size_t i; |
| 231 | for (i = 0; i < self->word_alloc; i++) |
| 232 | if (self->words[i]) |
| 233 | return 0; |
| 234 | return 1; |
| 235 | } |
| 236 | |
| 237 | int bitmap_equals(struct bitmap *self, struct bitmap *other) |
| 238 | { |
| 239 | struct bitmap *big, *small; |
| 240 | size_t i; |
| 241 | |
| 242 | if (self->word_alloc < other->word_alloc) { |
| 243 | small = self; |
| 244 | big = other; |
| 245 | } else { |
| 246 | small = other; |
| 247 | big = self; |
| 248 | } |
| 249 | |
| 250 | for (i = 0; i < small->word_alloc; ++i) { |
| 251 | if (small->words[i] != big->words[i]) |
| 252 | return 0; |
| 253 | } |
| 254 | |
| 255 | for (; i < big->word_alloc; ++i) { |
| 256 | if (big->words[i] != 0) |
| 257 | return 0; |
| 258 | } |
| 259 | |
| 260 | return 1; |
| 261 | } |
| 262 | |
| 263 | int bitmap_equals_ewah(struct bitmap *self, struct ewah_bitmap *other) |
| 264 | { |
| 265 | struct ewah_iterator it; |
| 266 | eword_t word; |
| 267 | size_t i = 0; |
| 268 | |
| 269 | ewah_iterator_init(&it, other); |
| 270 | |
| 271 | while (ewah_iterator_next(&word, &it)) |
| 272 | if (word != (i < self->word_alloc ? self->words[i++] : 0)) |
| 273 | return 0; |
| 274 | |
| 275 | for (; i < self->word_alloc; i++) |
| 276 | if (self->words[i]) |
| 277 | return 0; |
| 278 | |
| 279 | return 1; |
| 280 | } |
| 281 | |
| 282 | int bitmap_is_subset(struct bitmap *self, struct bitmap *other) |
| 283 | { |
| 284 | size_t common_size, i; |
| 285 | |
| 286 | if (self->word_alloc < other->word_alloc) |
| 287 | common_size = self->word_alloc; |
| 288 | else { |
| 289 | common_size = other->word_alloc; |
| 290 | for (i = common_size; i < self->word_alloc; i++) { |
| 291 | if (self->words[i]) |
| 292 | return 1; |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | for (i = 0; i < common_size; i++) { |
| 297 | if (self->words[i] & ~other->words[i]) |
| 298 | return 1; |
| 299 | } |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | void bitmap_free(struct bitmap *bitmap) |
| 304 | { |
| 305 | if (!bitmap) |
| 306 | return; |
| 307 | |
| 308 | free(bitmap->words); |
| 309 | free(bitmap); |
| 310 | } |