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  * Free all the memory of the bitmap
  77  */
  78 void ewah_free(struct ewah_bitmap *self);
  79
  80 int ewah_serialize_to(struct ewah_bitmap *self,
  81                       int (*write_fun)(void *out, const void *buf, size_t len),
  82                       void *out);
  83 int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *);
  84
  85 ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len);
  86
  87 uint32_t ewah_checksum(struct ewah_bitmap *self);
  88
  89 /**
  90  * Call the given callback with the position of every single bit
  91  * that has been set on the bitmap.
  92  *
  93  * This is an efficient operation that does not fully decompress
  94  * the bitmap.
  95  */
  96 void ewah_each_bit(struct ewah_bitmap *self, ewah_callback callback, void *payload);
  97
  98 /**
  99  * Set a given bit on the bitmap.
 100  *
 101  * The bit at position `pos` will be set to true. Because of the
 102  * way that the bitmap is compressed, a set bit cannot be unset
 103  * later on.
 104  *
 105  * Furthermore, since the bitmap uses streaming compression, bits
 106  * can only set incrementally.
 107  *
 108  * E.g.
 109  *              ewah_set(bitmap, 1); // ok
 110  *              ewah_set(bitmap, 76); // ok
 111  *              ewah_set(bitmap, 77); // ok
 112  *              ewah_set(bitmap, 8712800127); // ok
 113  *              ewah_set(bitmap, 25); // failed, assert raised
 114  */
 115 void ewah_set(struct ewah_bitmap *self, size_t i);
 116
 117 struct ewah_iterator {
 118         const eword_t *buffer;
 119         size_t buffer_size;
 120
 121         size_t pointer;
 122         eword_t compressed, literals;
 123         eword_t rl, lw;
 124         int b;
 125 };
 126
 127 /**
 128  * Initialize a new iterator to run through the bitmap in uncompressed form.
 129  *
 130  * The iterator can be stack allocated. The underlying bitmap must not be freed
 131  * before the iteration is over.
 132  *
 133  * E.g.
 134  *
 135  *              struct ewah_bitmap *bitmap = ewah_new();
 136  *              struct ewah_iterator it;
 137  *
 138  *              ewah_iterator_init(&it, bitmap);
 139  */
 140 void ewah_iterator_init(struct ewah_iterator *it, struct ewah_bitmap *parent);
 141
 142 /**
 143  * Yield every single word in the bitmap in uncompressed form. This is:
 144  * yield single words (32-64 bits) where each bit represents an actual
 145  * bit from the bitmap.
 146  *
 147  * Return: true if a word was yield, false if there are no words left
 148  */
 149 int ewah_iterator_next(eword_t *next, struct ewah_iterator *it);
 150
 151 void ewah_xor(
 152         struct ewah_bitmap *ewah_i,
 153         struct ewah_bitmap *ewah_j,
 154         struct ewah_bitmap *out);
 155
 156 /**
 157  * Direct word access
 158  */
 159 size_t ewah_add_empty_words(struct ewah_bitmap *self, int v, size_t number);
 160 void ewah_add_dirty_words(
 161         struct ewah_bitmap *self, const eword_t *buffer, size_t number, int negate);
 162 size_t ewah_add(struct ewah_bitmap *self, eword_t word);
 163
 164
 165 /**
 166  * Uncompressed, old-school bitmap that can be efficiently compressed
 167  * into an `ewah_bitmap`.
 168  */
 169 struct bitmap {
 170         eword_t *words;
 171         size_t word_alloc;
 172 };
 173
 174 struct bitmap *bitmap_new(void);
 175 struct bitmap *bitmap_word_alloc(size_t word_alloc);
 176 void bitmap_set(struct bitmap *self, size_t pos);
 177 void bitmap_unset(struct bitmap *self, size_t pos);
 178 int bitmap_get(struct bitmap *self, size_t pos);
 179 void bitmap_reset(struct bitmap *self);
 180 void bitmap_free(struct bitmap *self);
 181 int bitmap_equals(struct bitmap *self, struct bitmap *other);
 182 int bitmap_is_subset(struct bitmap *self, struct bitmap *super);
 183
 184 struct ewah_bitmap * bitmap_to_ewah(struct bitmap *bitmap);
 185 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah);
 186
 187 void bitmap_and_not(struct bitmap *self, struct bitmap *other);
 188 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other);
 189 void bitmap_or(struct bitmap *self, const struct bitmap *other);
 190
 191 size_t bitmap_popcount(struct bitmap *self);
 192
 193 #endif