2 * Copyright © 2012 Google, Inc.
4 * This is part of HarfBuzz, a text shaping library.
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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24 * Google Author(s): Behdad Esfahbod
27 #ifndef HB_SET_PRIVATE_HH
28 #define HB_SET_PRIVATE_HH
30 #include "hb-private.hh"
32 #include "hb-object-private.hh"
36 * The set digests here implement various "filters" that support
37 * "approximate member query". Conceptually these are like Bloom
38 * Filter and Quotient Filter, however, much smaller, faster, and
39 * designed to fit the requirements of our uses for glyph coverage
40 * queries. As a result, our filters have much higher.
43 template <typename mask_t, unsigned int shift>
44 struct hb_set_digest_lowest_bits_t
48 static const unsigned int mask_bytes = sizeof (mask_t);
49 static const unsigned int mask_bits = sizeof (mask_t) * 8;
50 static const unsigned int num_bits = 0
51 + (mask_bytes >= 1 ? 3 : 0)
52 + (mask_bytes >= 2 ? 1 : 0)
53 + (mask_bytes >= 4 ? 1 : 0)
54 + (mask_bytes >= 8 ? 1 : 0)
55 + (mask_bytes >= 16? 1 : 0)
58 ASSERT_STATIC (shift < sizeof (hb_codepoint_t) * 8);
59 ASSERT_STATIC (shift + num_bits <= sizeof (hb_codepoint_t) * 8);
61 inline void init (void) {
65 inline void add (hb_codepoint_t g) {
69 inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
70 if ((b >> shift) - (a >> shift) >= mask_bits - 1)
73 mask_t ma = mask_for (a);
74 mask_t mb = mask_for (b);
75 mask |= mb + (mb - ma) - (mb < ma);
79 inline bool may_have (hb_codepoint_t g) const {
80 return !!(mask & mask_for (g));
85 static inline mask_t mask_for (hb_codepoint_t g) {
86 return ((mask_t) 1) << ((g >> shift) & (mask_bits - 1));
91 template <typename head_t, typename tail_t>
92 struct hb_set_digest_combiner_t
96 inline void init (void) {
101 inline void add (hb_codepoint_t g) {
106 inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
107 head.add_range (a, b);
108 tail.add_range (a, b);
111 inline bool may_have (hb_codepoint_t g) const {
112 return head.may_have (g) && tail.may_have (g);
124 * This is a combination of digests that performs "best".
125 * There is not much science to this: it's a result of intuition
128 typedef hb_set_digest_combiner_t
130 hb_set_digest_lowest_bits_t<unsigned long, 4>,
131 hb_set_digest_combiner_t
133 hb_set_digest_lowest_bits_t<unsigned long, 0>,
134 hb_set_digest_lowest_bits_t<unsigned long, 9>
145 /* TODO Make this faster and memmory efficient. */
149 hb_object_header_t header;
153 inline void init (void) {
157 inline void fini (void) {
159 inline void clear (void) {
160 if (unlikely (hb_object_is_inert (this)))
163 memset (elts, 0, sizeof elts);
165 inline bool is_empty (void) const {
166 for (unsigned int i = 0; i < ARRAY_LENGTH (elts); i++)
171 inline void add (hb_codepoint_t g)
173 if (unlikely (in_error)) return;
174 if (unlikely (g == SENTINEL)) return;
175 if (unlikely (g > MAX_G)) return;
178 inline void add_range (hb_codepoint_t a, hb_codepoint_t b)
180 if (unlikely (in_error)) return;
182 for (unsigned int i = a; i < b + 1; i++)
185 inline void del (hb_codepoint_t g)
187 if (unlikely (in_error)) return;
188 if (unlikely (g > MAX_G)) return;
189 elt (g) &= ~mask (g);
191 inline void del_range (hb_codepoint_t a, hb_codepoint_t b)
193 if (unlikely (in_error)) return;
195 for (unsigned int i = a; i < b + 1; i++)
198 inline bool has (hb_codepoint_t g) const
200 if (unlikely (g > MAX_G)) return false;
201 return !!(elt (g) & mask (g));
203 inline bool intersects (hb_codepoint_t first,
204 hb_codepoint_t last) const
206 if (unlikely (first > MAX_G)) return false;
207 if (unlikely (last > MAX_G)) last = MAX_G;
208 unsigned int end = last + 1;
209 for (hb_codepoint_t i = first; i < end; i++)
214 inline bool is_equal (const hb_set_t *other) const
216 for (unsigned int i = 0; i < ELTS; i++)
217 if (elts[i] != other->elts[i])
221 inline void set (const hb_set_t *other)
223 if (unlikely (in_error)) return;
224 for (unsigned int i = 0; i < ELTS; i++)
225 elts[i] = other->elts[i];
227 inline void union_ (const hb_set_t *other)
229 if (unlikely (in_error)) return;
230 for (unsigned int i = 0; i < ELTS; i++)
231 elts[i] |= other->elts[i];
233 inline void intersect (const hb_set_t *other)
235 if (unlikely (in_error)) return;
236 for (unsigned int i = 0; i < ELTS; i++)
237 elts[i] &= other->elts[i];
239 inline void subtract (const hb_set_t *other)
241 if (unlikely (in_error)) return;
242 for (unsigned int i = 0; i < ELTS; i++)
243 elts[i] &= ~other->elts[i];
245 inline void symmetric_difference (const hb_set_t *other)
247 if (unlikely (in_error)) return;
248 for (unsigned int i = 0; i < ELTS; i++)
249 elts[i] ^= other->elts[i];
251 inline void invert (void)
253 if (unlikely (in_error)) return;
254 for (unsigned int i = 0; i < ELTS; i++)
257 inline bool next (hb_codepoint_t *codepoint) const
259 if (unlikely (*codepoint == SENTINEL)) {
260 hb_codepoint_t i = get_min ();
267 for (hb_codepoint_t i = *codepoint + 1; i < MAX_G + 1; i++)
274 inline bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const
283 while (next (&i) && i == *last + 1)
289 inline unsigned int get_population (void) const
291 unsigned int count = 0;
292 for (unsigned int i = 0; i < ELTS; i++)
293 count += _hb_popcount32 (elts[i]);
296 inline hb_codepoint_t get_min (void) const
298 for (unsigned int i = 0; i < ELTS; i++)
300 for (unsigned int j = 0; j < BITS; j++)
301 if (elts[i] & (1 << j))
305 inline hb_codepoint_t get_max (void) const
307 for (unsigned int i = ELTS; i; i--)
309 for (unsigned int j = BITS; j; j--)
310 if (elts[i - 1] & (1 << (j - 1)))
311 return (i - 1) * BITS + (j - 1);
315 typedef uint32_t elt_t;
316 static const unsigned int MAX_G = 65536 - 1; /* XXX Fix this... */
317 static const unsigned int SHIFT = 5;
318 static const unsigned int BITS = (1 << SHIFT);
319 static const unsigned int MASK = BITS - 1;
320 static const unsigned int ELTS = (MAX_G + 1 + (BITS - 1)) / BITS;
321 static const hb_codepoint_t SENTINEL = (hb_codepoint_t) -1;
323 elt_t &elt (hb_codepoint_t g) { return elts[g >> SHIFT]; }
324 elt_t elt (hb_codepoint_t g) const { return elts[g >> SHIFT]; }
325 elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & MASK); }
327 elt_t elts[ELTS]; /* XXX 8kb */
329 ASSERT_STATIC (sizeof (elt_t) * 8 == BITS);
330 ASSERT_STATIC (sizeof (elt_t) * 8 * ELTS > MAX_G);
335 #endif /* HB_SET_PRIVATE_HH */