ewah/ewok.h

   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 #ifndef __EWOK_BITMAP_H__
  20 #define __EWOK_BITMAP_H__
  21
  22 struct strbuf;
  23 typedef uint64_t eword_t;
  24 #define BITS_IN_EWORD (sizeof(eword_t) * 8)
  25
  26 /**
  27  * Do not use __builtin_popcountll. The GCC implementation
  28  * is notoriously slow on all platforms.
  29  *
  30  * See: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36041
  31  */
  32 static inline uint32_t ewah_bit_popcount64(uint64_t x)
  33 {
  34         x = (x & 0x5555555555555555ULL) + ((x >>  1) & 0x5555555555555555ULL);
  35         x = (x & 0x3333333333333333ULL) + ((x >>  2) & 0x3333333333333333ULL);
  36         x = (x & 0x0F0F0F0F0F0F0F0FULL) + ((x >>  4) & 0x0F0F0F0F0F0F0F0FULL);
  37         return (x * 0x0101010101010101ULL) >> 56;
  38 }
  39
  40 /* __builtin_ctzll was not available until 3.4.0 */
  41 #if defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3  && __GNUC_MINOR > 3))
  42 #define ewah_bit_ctz64(x) __builtin_ctzll(x)
  43 #else
  44 static inline int ewah_bit_ctz64(uint64_t x)
  45 {
  46         int n = 0;
  47         if ((x & 0xffffffff) == 0) { x >>= 32; n += 32; }
  48         if ((x &     0xffff) == 0) { x >>= 16; n += 16; }
  49         if ((x &       0xff) == 0) { x >>=  8; n +=  8; }
  50         if ((x &        0xf) == 0) { x >>=  4; n +=  4; }
  51         if ((x &        0x3) == 0) { x >>=  2; n +=  2; }
  52         if ((x &        0x1) == 0) { x >>=  1; n +=  1; }
  53         return n + !x;
  54 }
  55 #endif
  56
  57 struct ewah_bitmap {
  58         eword_t *buffer;
  59         size_t buffer_size;
  60         size_t alloc_size;
  61         size_t bit_size;
  62         eword_t *rlw;
  63 };
  64
  65 typedef void (*ewah_callback)(size_t pos, void *);
  66
  67 struct ewah_bitmap *ewah_pool_new(void);
  68 void ewah_pool_free(struct ewah_bitmap *self);
  69
  70 /**
  71  * Allocate a new EWAH Compressed bitmap
  72  */
  73 struct ewah_bitmap *ewah_new(void);
  74
  75 /**
  76  * Clear all the bits in the bitmap. Does not free or resize
  77  * memory.
  78  */
  79 void ewah_clear(struct ewah_bitmap *self);
  80
  81 /**
  82  * Free all the memory of the bitmap
  83  */
  84 void ewah_free(struct ewah_bitmap *self);
  85
  86 int ewah_serialize_to(struct ewah_bitmap *self,
  87                       int (*write_fun)(void *out, const void *buf, size_t len),
  88                       void *out);
  89 int ewah_serialize(struct ewah_bitmap *self, int fd);
  90 int ewah_serialize_native(struct ewah_bitmap *self, int fd);
  91 int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *);
  92
  93 int ewah_deserialize(struct ewah_bitmap *self, int fd);
  94 int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len);
  95
  96 uint32_t ewah_checksum(struct ewah_bitmap *self);
  97
  98 /**
  99  * Logical not (bitwise negation) in-place on the bitmap
 100  *
 101  * This operation is linear time based on the size of the bitmap.
 102  */
 103 void ewah_not(struct ewah_bitmap *self);
 104
 105 /**
 106  * Call the given callback with the position of every single bit
 107  * that has been set on the bitmap.
 108  *
 109  * This is an efficient operation that does not fully decompress
 110  * the bitmap.
 111  */
 112 void ewah_each_bit(struct ewah_bitmap *self, ewah_callback callback, void *payload);
 113
 114 /**
 115  * Set a given bit on the bitmap.
 116  *
 117  * The bit at position `pos` will be set to true. Because of the
 118  * way that the bitmap is compressed, a set bit cannot be unset
 119  * later on.
 120  *
 121  * Furthermore, since the bitmap uses streaming compression, bits
 122  * can only set incrementally.
 123  *
 124  * E.g.
 125  *              ewah_set(bitmap, 1); // ok
 126  *              ewah_set(bitmap, 76); // ok
 127  *              ewah_set(bitmap, 77); // ok
 128  *              ewah_set(bitmap, 8712800127); // ok
 129  *              ewah_set(bitmap, 25); // failed, assert raised
 130  */
 131 void ewah_set(struct ewah_bitmap *self, size_t i);
 132
 133 struct ewah_iterator {
 134         const eword_t *buffer;
 135         size_t buffer_size;
 136
 137         size_t pointer;
 138         eword_t compressed, literals;
 139         eword_t rl, lw;
 140         int b;
 141 };
 142
 143 /**
 144  * Initialize a new iterator to run through the bitmap in uncompressed form.
 145  *
 146  * The iterator can be stack allocated. The underlying bitmap must not be freed
 147  * before the iteration is over.
 148  *
 149  * E.g.
 150  *
 151  *              struct ewah_bitmap *bitmap = ewah_new();
 152  *              struct ewah_iterator it;
 153  *
 154  *              ewah_iterator_init(&it, bitmap);
 155  */
 156 void ewah_iterator_init(struct ewah_iterator *it, struct ewah_bitmap *parent);
 157
 158 /**
 159  * Yield every single word in the bitmap in uncompressed form. This is:
 160  * yield single words (32-64 bits) where each bit represents an actual
 161  * bit from the bitmap.
 162  *
 163  * Return: true if a word was yield, false if there are no words left
 164  */
 165 int ewah_iterator_next(eword_t *next, struct ewah_iterator *it);
 166
 167 void ewah_or(
 168         struct ewah_bitmap *ewah_i,
 169         struct ewah_bitmap *ewah_j,
 170         struct ewah_bitmap *out);
 171
 172 void ewah_and_not(
 173         struct ewah_bitmap *ewah_i,
 174         struct ewah_bitmap *ewah_j,
 175         struct ewah_bitmap *out);
 176
 177 void ewah_xor(
 178         struct ewah_bitmap *ewah_i,
 179         struct ewah_bitmap *ewah_j,
 180         struct ewah_bitmap *out);
 181
 182 void ewah_and(
 183         struct ewah_bitmap *ewah_i,
 184         struct ewah_bitmap *ewah_j,
 185         struct ewah_bitmap *out);
 186
 187 /**
 188  * Direct word access
 189  */
 190 size_t ewah_add_empty_words(struct ewah_bitmap *self, int v, size_t number);
 191 void ewah_add_dirty_words(
 192         struct ewah_bitmap *self, const eword_t *buffer, size_t number, int negate);
 193 size_t ewah_add(struct ewah_bitmap *self, eword_t word);
 194
 195
 196 /**
 197  * Uncompressed, old-school bitmap that can be efficiently compressed
 198  * into an `ewah_bitmap`.
 199  */
 200 struct bitmap {
 201         eword_t *words;
 202         size_t word_alloc;
 203 };
 204
 205 struct bitmap *bitmap_new(void);
 206 void bitmap_set(struct bitmap *self, size_t pos);
 207 void bitmap_clear(struct bitmap *self, size_t pos);
 208 int bitmap_get(struct bitmap *self, size_t pos);
 209 void bitmap_reset(struct bitmap *self);
 210 void bitmap_free(struct bitmap *self);
 211 int bitmap_equals(struct bitmap *self, struct bitmap *other);
 212 int bitmap_is_subset(struct bitmap *self, struct bitmap *super);
 213
 214 struct ewah_bitmap * bitmap_to_ewah(struct bitmap *bitmap);
 215 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah);
 216
 217 void bitmap_and_not(struct bitmap *self, struct bitmap *other);
 218 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other);
 219 void bitmap_or(struct bitmap *self, const struct bitmap *other);
 220
 221 void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data);
 222 size_t bitmap_popcount(struct bitmap *self);
 223
 224 #endif