freshlybakedca.ke
Git fork
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
25struct 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
33struct bitmap *bitmap_new(void)
34{
35 return bitmap_word_alloc(32);
36}
37
38struct 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
45static 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 memset(self->words + old_size, 0x0,
50 (self->word_alloc - old_size) * sizeof(eword_t));
51}
52
53void bitmap_set(struct bitmap *self, size_t pos)
54{
55 size_t block = EWAH_BLOCK(pos);
56
57 bitmap_grow(self, block + 1);
58 self->words[block] |= EWAH_MASK(pos);
59}
60
61void bitmap_unset(struct bitmap *self, size_t pos)
62{
63 size_t block = EWAH_BLOCK(pos);
64
65 if (block < self->word_alloc)
66 self->words[block] &= ~EWAH_MASK(pos);
67}
68
69int bitmap_get(struct bitmap *self, size_t pos)
70{
71 size_t block = EWAH_BLOCK(pos);
72 return block < self->word_alloc &&
73 (self->words[block] & EWAH_MASK(pos)) != 0;
74}
75
76struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
77{
78 struct ewah_bitmap *ewah = ewah_new();
79 size_t i, running_empty_words = 0;
80 eword_t last_word = 0;
81
82 for (i = 0; i < bitmap->word_alloc; ++i) {
83 if (bitmap->words[i] == 0) {
84 running_empty_words++;
85 continue;
86 }
87
88 if (last_word != 0)
89 ewah_add(ewah, last_word);
90
91 if (running_empty_words > 0) {
92 ewah_add_empty_words(ewah, 0, running_empty_words);
93 running_empty_words = 0;
94 }
95
96 last_word = bitmap->words[i];
97 }
98
99 ewah_add(ewah, last_word);
100 return ewah;
101}
102
103struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
104{
105 struct bitmap *bitmap = bitmap_new();
106 struct ewah_iterator it;
107 eword_t blowup;
108 size_t i = 0;
109
110 ewah_iterator_init(&it, ewah);
111
112 while (ewah_iterator_next(&blowup, &it)) {
113 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
114 bitmap->words[i++] = blowup;
115 }
116
117 bitmap->word_alloc = i;
118 return bitmap;
119}
120
121void bitmap_and_not(struct bitmap *self, struct bitmap *other)
122{
123 const size_t count = (self->word_alloc < other->word_alloc) ?
124 self->word_alloc : other->word_alloc;
125
126 size_t i;
127
128 for (i = 0; i < count; ++i)
129 self->words[i] &= ~other->words[i];
130}
131
132void bitmap_or(struct bitmap *self, const struct bitmap *other)
133{
134 size_t i;
135
136 bitmap_grow(self, other->word_alloc);
137 for (i = 0; i < other->word_alloc; i++)
138 self->words[i] |= other->words[i];
139}
140
141int ewah_bitmap_is_subset(struct ewah_bitmap *self, struct bitmap *other)
142{
143 struct ewah_iterator it;
144 eword_t word;
145 size_t i;
146
147 ewah_iterator_init(&it, self);
148
149 for (i = 0; i < other->word_alloc; i++) {
150 if (!ewah_iterator_next(&word, &it)) {
151 /*
152 * If we reached the end of `self`, and haven't
153 * rejected `self` as a possible subset of
154 * `other` yet, then we are done and `self` is
155 * indeed a subset of `other`.
156 */
157 return 1;
158 }
159 if (word & ~other->words[i]) {
160 /*
161 * Otherwise, compare the next two pairs of
162 * words. If the word from `self` has bit(s) not
163 * in the word from `other`, `self` is not a
164 * subset of `other`.
165 */
166 return 0;
167 }
168 }
169
170 /*
171 * If we got to this point, there may be zero or more words
172 * remaining in `self`, with no remaining words left in `other`.
173 * If there are any bits set in the remaining word(s) in `self`,
174 * then `self` is not a subset of `other`.
175 */
176 while (ewah_iterator_next(&word, &it))
177 if (word)
178 return 0;
179
180 /* `self` is definitely a subset of `other` */
181 return 1;
182}
183
184void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
185{
186 size_t original_size = self->word_alloc;
187 size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
188 size_t i = 0;
189 struct ewah_iterator it;
190 eword_t word;
191
192 if (self->word_alloc < other_final) {
193 self->word_alloc = other_final;
194 REALLOC_ARRAY(self->words, self->word_alloc);
195 memset(self->words + original_size, 0x0,
196 (self->word_alloc - original_size) * sizeof(eword_t));
197 }
198
199 ewah_iterator_init(&it, other);
200
201 while (ewah_iterator_next(&word, &it))
202 self->words[i++] |= word;
203}
204
205size_t bitmap_popcount(struct bitmap *self)
206{
207 size_t i, count = 0;
208
209 for (i = 0; i < self->word_alloc; ++i)
210 count += ewah_bit_popcount64(self->words[i]);
211
212 return count;
213}
214
215size_t ewah_bitmap_popcount(struct ewah_bitmap *self)
216{
217 struct ewah_iterator it;
218 eword_t word;
219 size_t count = 0;
220
221 ewah_iterator_init(&it, self);
222
223 while (ewah_iterator_next(&word, &it))
224 count += ewah_bit_popcount64(word);
225
226 return count;
227}
228
229int bitmap_is_empty(struct bitmap *self)
230{
231 size_t i;
232 for (i = 0; i < self->word_alloc; i++)
233 if (self->words[i])
234 return 0;
235 return 1;
236}
237
238int bitmap_equals(struct bitmap *self, struct bitmap *other)
239{
240 struct bitmap *big, *small;
241 size_t i;
242
243 if (self->word_alloc < other->word_alloc) {
244 small = self;
245 big = other;
246 } else {
247 small = other;
248 big = self;
249 }
250
251 for (i = 0; i < small->word_alloc; ++i) {
252 if (small->words[i] != big->words[i])
253 return 0;
254 }
255
256 for (; i < big->word_alloc; ++i) {
257 if (big->words[i] != 0)
258 return 0;
259 }
260
261 return 1;
262}
263
264int bitmap_equals_ewah(struct bitmap *self, struct ewah_bitmap *other)
265{
266 struct ewah_iterator it;
267 eword_t word;
268 size_t i = 0;
269
270 ewah_iterator_init(&it, other);
271
272 while (ewah_iterator_next(&word, &it))
273 if (word != (i < self->word_alloc ? self->words[i++] : 0))
274 return 0;
275
276 for (; i < self->word_alloc; i++)
277 if (self->words[i])
278 return 0;
279
280 return 1;
281}
282
283int bitmap_is_subset(struct bitmap *self, struct bitmap *other)
284{
285 size_t common_size, i;
286
287 if (self->word_alloc < other->word_alloc)
288 common_size = self->word_alloc;
289 else {
290 common_size = other->word_alloc;
291 for (i = common_size; i < self->word_alloc; i++) {
292 if (self->words[i])
293 return 1;
294 }
295 }
296
297 for (i = 0; i < common_size; i++) {
298 if (self->words[i] & ~other->words[i])
299 return 1;
300 }
301 return 0;
302}
303
304void bitmap_free(struct bitmap *bitmap)
305{
306 if (!bitmap)
307 return;
308
309 free(bitmap->words);
310 free(bitmap);
311}