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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  */
  20 #ifndef __EWOK_BITMAP_H__
  21 #define __EWOK_BITMAP_H__
  22
  23 struct strbuf;
  24 typedef uint64_t eword_t;
  25 #define BITS_IN_EWORD (sizeof(eword_t) * 8)
  26
  27 /**
  28  * Do not use __builtin_popcountll. The GCC implementation
  29  * is notoriously slow on all platforms.
  30  *
  31  * See: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36041
  32  */
  33 static inline uint32_t ewah_bit_popcount64(uint64_t x)
  34 {
  35         x = (x & 0x5555555555555555ULL) + ((x >>  1) & 0x5555555555555555ULL);
  36         x = (x & 0x3333333333333333ULL) + ((x >>  2) & 0x3333333333333333ULL);
  37         x = (x & 0x0F0F0F0F0F0F0F0FULL) + ((x >>  4) & 0x0F0F0F0F0F0F0F0FULL);
  38         return (x * 0x0101010101010101ULL) >> 56;
  39 }
  40
  41 /* __builtin_ctzll was not available until 3.4.0 */
  42 #if defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3  && __GNUC_MINOR > 3))
  43 #define ewah_bit_ctz64(x) __builtin_ctzll(x)
  44 #else
  45 static inline int ewah_bit_ctz64(uint64_t x)
  46 {
  47         int n = 0;
  48         if ((x & 0xffffffff) == 0) { x >>= 32; n += 32; }
  49         if ((x &     0xffff) == 0) { x >>= 16; n += 16; }
  50         if ((x &       0xff) == 0) { x >>=  8; n +=  8; }
  51         if ((x &        0xf) == 0) { x >>=  4; n +=  4; }
  52         if ((x &        0x3) == 0) { x >>=  2; n +=  2; }
  53         if ((x &        0x1) == 0) { x >>=  1; n +=  1; }
  54         return n + !x;
  55 }
  56 #endif
  57
  58 struct ewah_bitmap {
  59         eword_t *buffer;
  60         size_t buffer_size;
  61         size_t alloc_size;
  62         size_t bit_size;
  63         eword_t *rlw;
  64 };
  65
  66 typedef void (*ewah_callback)(size_t pos, void *);
  67
  68 struct ewah_bitmap *ewah_pool_new(void);
  69 void ewah_pool_free(struct ewah_bitmap *self);
  70
  71 /**
  72  * Allocate a new EWAH Compressed bitmap
  73  */
  74 struct ewah_bitmap *ewah_new(void);
  75
  76 /**
  77  * Clear all the bits in the bitmap. Does not free or resize
  78  * memory.
  79  */
  80 void ewah_clear(struct ewah_bitmap *self);
  81
  82 /**
  83  * Free all the memory of the bitmap
  84  */
  85 void ewah_free(struct ewah_bitmap *self);
  86
  87 int ewah_serialize_to(struct ewah_bitmap *self,
  88                       int (*write_fun)(void *out, const void *buf, size_t len),
  89                       void *out);
  90 int ewah_serialize(struct ewah_bitmap *self, int fd);
  91 int ewah_serialize_native(struct ewah_bitmap *self, int fd);
  92 int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *);
  93
  94 int ewah_deserialize(struct ewah_bitmap *self, int fd);
  95 int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len);
  96
  97 uint32_t ewah_checksum(struct ewah_bitmap *self);
  98
  99 /**
 100  * Logical not (bitwise negation) in-place on the bitmap
 101  *
 102  * This operation is linear time based on the size of the bitmap.
 103  */
 104 void ewah_not(struct ewah_bitmap *self);
 105
 106 /**
 107  * Call the given callback with the position of every single bit
 108  * that has been set on the bitmap.
 109  *
 110  * This is an efficient operation that does not fully decompress
 111  * the bitmap.
 112  */
 113 void ewah_each_bit(struct ewah_bitmap *self, ewah_callback callback, void *payload);
 114
 115 /**
 116  * Set a given bit on the bitmap.
 117  *
 118  * The bit at position `pos` will be set to true. Because of the
 119  * way that the bitmap is compressed, a set bit cannot be unset
 120  * later on.
 121  *
 122  * Furthermore, since the bitmap uses streaming compression, bits
 123  * can only set incrementally.
 124  *
 125  * E.g.
 126  *              ewah_set(bitmap, 1); // ok
 127  *              ewah_set(bitmap, 76); // ok
 128  *              ewah_set(bitmap, 77); // ok
 129  *              ewah_set(bitmap, 8712800127); // ok
 130  *              ewah_set(bitmap, 25); // failed, assert raised
 131  */
 132 void ewah_set(struct ewah_bitmap *self, size_t i);
 133
 134 struct ewah_iterator {
 135         const eword_t *buffer;
 136         size_t buffer_size;
 137
 138         size_t pointer;
 139         eword_t compressed, literals;
 140         eword_t rl, lw;
 141         int b;
 142 };
 143
 144 /**
 145  * Initialize a new iterator to run through the bitmap in uncompressed form.
 146  *
 147  * The iterator can be stack allocated. The underlying bitmap must not be freed
 148  * before the iteration is over.
 149  *
 150  * E.g.
 151  *
 152  *              struct ewah_bitmap *bitmap = ewah_new();
 153  *              struct ewah_iterator it;
 154  *
 155  *              ewah_iterator_init(&it, bitmap);
 156  */
 157 void ewah_iterator_init(struct ewah_iterator *it, struct ewah_bitmap *parent);
 158
 159 /**
 160  * Yield every single word in the bitmap in uncompressed form. This is:
 161  * yield single words (32-64 bits) where each bit represents an actual
 162  * bit from the bitmap.
 163  *
 164  * Return: true if a word was yield, false if there are no words left
 165  */
 166 int ewah_iterator_next(eword_t *next, struct ewah_iterator *it);
 167
 168 void ewah_or(
 169         struct ewah_bitmap *ewah_i,
 170         struct ewah_bitmap *ewah_j,
 171         struct ewah_bitmap *out);
 172
 173 void ewah_and_not(
 174         struct ewah_bitmap *ewah_i,
 175         struct ewah_bitmap *ewah_j,
 176         struct ewah_bitmap *out);
 177
 178 void ewah_xor(
 179         struct ewah_bitmap *ewah_i,
 180         struct ewah_bitmap *ewah_j,
 181         struct ewah_bitmap *out);
 182
 183 void ewah_and(
 184         struct ewah_bitmap *ewah_i,
 185         struct ewah_bitmap *ewah_j,
 186         struct ewah_bitmap *out);
 187
 188 /**
 189  * Direct word access
 190  */
 191 size_t ewah_add_empty_words(struct ewah_bitmap *self, int v, size_t number);
 192 void ewah_add_dirty_words(
 193         struct ewah_bitmap *self, const eword_t *buffer, size_t number, int negate);
 194 size_t ewah_add(struct ewah_bitmap *self, eword_t word);
 195
 196
 197 /**
 198  * Uncompressed, old-school bitmap that can be efficiently compressed
 199  * into an `ewah_bitmap`.
 200  */
 201 struct bitmap {
 202         eword_t *words;
 203         size_t word_alloc;
 204 };
 205
 206 struct bitmap *bitmap_new(void);
 207 void bitmap_set(struct bitmap *self, size_t pos);
 208 void bitmap_clear(struct bitmap *self, size_t pos);
 209 int bitmap_get(struct bitmap *self, size_t pos);
 210 void bitmap_reset(struct bitmap *self);
 211 void bitmap_free(struct bitmap *self);
 212 int bitmap_equals(struct bitmap *self, struct bitmap *other);
 213 int bitmap_is_subset(struct bitmap *self, struct bitmap *super);
 214
 215 struct ewah_bitmap * bitmap_to_ewah(struct bitmap *bitmap);
 216 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah);
 217
 218 void bitmap_and_not(struct bitmap *self, struct bitmap *other);
 219 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other);
 220 void bitmap_or(struct bitmap *self, const struct bitmap *other);
 221
 222 void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data);
 223 size_t bitmap_popcount(struct bitmap *self);
 224
 225 #endif