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Diffstat (limited to 'gfx/harfbuzz/src/hb-set-private.hh')
| -rw-r--r-- | gfx/harfbuzz/src/hb-set-private.hh | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-set-private.hh b/gfx/harfbuzz/src/hb-set-private.hh new file mode 100644 index 000000000..e2010d762 --- /dev/null +++ b/gfx/harfbuzz/src/hb-set-private.hh @@ -0,0 +1,402 @@ +/* + * Copyright © 2012 Google, Inc. + * + * This is part of HarfBuzz, a text shaping library. + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and its documentation for any purpose, provided that the + * above copyright notice and the following two paragraphs appear in + * all copies of this software. + * + * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES + * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN + * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, + * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS + * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + * Google Author(s): Behdad Esfahbod + */ + +#ifndef HB_SET_PRIVATE_HH +#define HB_SET_PRIVATE_HH + +#include "hb-private.hh" +#include "hb-object-private.hh" + + +/* + * The set digests here implement various "filters" that support + * "approximate member query". Conceptually these are like Bloom + * Filter and Quotient Filter, however, much smaller, faster, and + * designed to fit the requirements of our uses for glyph coverage + * queries. + * + * Our filters are highly accurate if the lookup covers fairly local + * set of glyphs, but fully flooded and ineffective if coverage is + * all over the place. + * + * The frozen-set can be used instead of a digest, to trade more + * memory for 100% accuracy, but in practice, that doesn't look like + * an attractive trade-off. + */ + +template <typename mask_t, unsigned int shift> +struct hb_set_digest_lowest_bits_t +{ + ASSERT_POD (); + + static const unsigned int mask_bytes = sizeof (mask_t); + static const unsigned int mask_bits = sizeof (mask_t) * 8; + static const unsigned int num_bits = 0 + + (mask_bytes >= 1 ? 3 : 0) + + (mask_bytes >= 2 ? 1 : 0) + + (mask_bytes >= 4 ? 1 : 0) + + (mask_bytes >= 8 ? 1 : 0) + + (mask_bytes >= 16? 1 : 0) + + 0; + + ASSERT_STATIC (shift < sizeof (hb_codepoint_t) * 8); + ASSERT_STATIC (shift + num_bits <= sizeof (hb_codepoint_t) * 8); + + inline void init (void) { + mask = 0; + } + + inline void add (hb_codepoint_t g) { + mask |= mask_for (g); + } + + inline void add_range (hb_codepoint_t a, hb_codepoint_t b) { + if ((b >> shift) - (a >> shift) >= mask_bits - 1) + mask = (mask_t) -1; + else { + mask_t ma = mask_for (a); + mask_t mb = mask_for (b); + mask |= mb + (mb - ma) - (mb < ma); + } + } + + inline bool may_have (hb_codepoint_t g) const { + return !!(mask & mask_for (g)); + } + + private: + + static inline mask_t mask_for (hb_codepoint_t g) { + return ((mask_t) 1) << ((g >> shift) & (mask_bits - 1)); + } + mask_t mask; +}; + +template <typename head_t, typename tail_t> +struct hb_set_digest_combiner_t +{ + ASSERT_POD (); + + inline void init (void) { + head.init (); + tail.init (); + } + + inline void add (hb_codepoint_t g) { + head.add (g); + tail.add (g); + } + + inline void add_range (hb_codepoint_t a, hb_codepoint_t b) { + head.add_range (a, b); + tail.add_range (a, b); + } + + inline bool may_have (hb_codepoint_t g) const { + return head.may_have (g) && tail.may_have (g); + } + + private: + head_t head; + tail_t tail; +}; + + +/* + * hb_set_digest_t + * + * This is a combination of digests that performs "best". + * There is not much science to this: it's a result of intuition + * and testing. + */ +typedef hb_set_digest_combiner_t +< + hb_set_digest_lowest_bits_t<unsigned long, 4>, + hb_set_digest_combiner_t + < + hb_set_digest_lowest_bits_t<unsigned long, 0>, + hb_set_digest_lowest_bits_t<unsigned long, 9> + > +> hb_set_digest_t; + + + +/* + * hb_set_t + */ + + +/* TODO Make this faster and memmory efficient. */ + +struct hb_set_t +{ + friend struct hb_frozen_set_t; + + hb_object_header_t header; + ASSERT_POD (); + bool in_error; + + inline void init (void) { + hb_object_init (this); + clear (); + } + inline void fini (void) { + } + inline void clear (void) { + if (unlikely (hb_object_is_inert (this))) + return; + in_error = false; + memset (elts, 0, sizeof elts); + } + inline bool is_empty (void) const { + for (unsigned int i = 0; i < ARRAY_LENGTH (elts); i++) + if (elts[i]) + return false; + return true; + } + inline void add (hb_codepoint_t g) + { + if (unlikely (in_error)) return; + if (unlikely (g == INVALID)) return; + if (unlikely (g > MAX_G)) return; + elt (g) |= mask (g); + } + inline void add_range (hb_codepoint_t a, hb_codepoint_t b) + { + if (unlikely (in_error)) return; + /* TODO Speedup */ + for (unsigned int i = a; i < b + 1; i++) + add (i); + } + inline void del (hb_codepoint_t g) + { + if (unlikely (in_error)) return; + if (unlikely (g > MAX_G)) return; + elt (g) &= ~mask (g); + } + inline void del_range (hb_codepoint_t a, hb_codepoint_t b) + { + if (unlikely (in_error)) return; + /* TODO Speedup */ + for (unsigned int i = a; i < b + 1; i++) + del (i); + } + inline bool has (hb_codepoint_t g) const + { + if (unlikely (g > MAX_G)) return false; + return !!(elt (g) & mask (g)); + } + inline bool intersects (hb_codepoint_t first, + hb_codepoint_t last) const + { + if (unlikely (first > MAX_G)) return false; + if (unlikely (last > MAX_G)) last = MAX_G; + unsigned int end = last + 1; + for (hb_codepoint_t i = first; i < end; i++) + if (has (i)) + return true; + return false; + } + inline bool is_equal (const hb_set_t *other) const + { + for (unsigned int i = 0; i < ELTS; i++) + if (elts[i] != other->elts[i]) + return false; + return true; + } + inline void set (const hb_set_t *other) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] = other->elts[i]; + } + inline void union_ (const hb_set_t *other) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] |= other->elts[i]; + } + inline void intersect (const hb_set_t *other) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] &= other->elts[i]; + } + inline void subtract (const hb_set_t *other) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] &= ~other->elts[i]; + } + inline void symmetric_difference (const hb_set_t *other) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] ^= other->elts[i]; + } + inline void invert (void) + { + if (unlikely (in_error)) return; + for (unsigned int i = 0; i < ELTS; i++) + elts[i] = ~elts[i]; + } + inline bool next (hb_codepoint_t *codepoint) const + { + if (unlikely (*codepoint == INVALID)) { + hb_codepoint_t i = get_min (); + if (i != INVALID) { + *codepoint = i; + return true; + } else { + *codepoint = INVALID; + return false; + } + } + for (hb_codepoint_t i = *codepoint + 1; i < MAX_G + 1; i++) + if (has (i)) { + *codepoint = i; + return true; + } + *codepoint = INVALID; + return false; + } + inline bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const + { + hb_codepoint_t i; + + i = *last; + if (!next (&i)) + { + *last = *first = INVALID; + return false; + } + + *last = *first = i; + while (next (&i) && i == *last + 1) + (*last)++; + + return true; + } + + inline unsigned int get_population (void) const + { + unsigned int count = 0; + for (unsigned int i = 0; i < ELTS; i++) + count += _hb_popcount32 (elts[i]); + return count; + } + inline hb_codepoint_t get_min (void) const + { + for (unsigned int i = 0; i < ELTS; i++) + if (elts[i]) + for (unsigned int j = 0; j < BITS; j++) + if (elts[i] & (1u << j)) + return i * BITS + j; + return INVALID; + } + inline hb_codepoint_t get_max (void) const + { + for (unsigned int i = ELTS; i; i--) + if (elts[i - 1]) + for (unsigned int j = BITS; j; j--) + if (elts[i - 1] & (1u << (j - 1))) + return (i - 1) * BITS + (j - 1); + return INVALID; + } + + typedef uint32_t elt_t; + static const unsigned int MAX_G = 65536 - 1; /* XXX Fix this... */ + static const unsigned int SHIFT = 5; + static const unsigned int BITS = (1 << SHIFT); + static const unsigned int MASK = BITS - 1; + static const unsigned int ELTS = (MAX_G + 1 + (BITS - 1)) / BITS; + static const hb_codepoint_t INVALID = HB_SET_VALUE_INVALID; + + elt_t &elt (hb_codepoint_t g) { return elts[g >> SHIFT]; } + elt_t const &elt (hb_codepoint_t g) const { return elts[g >> SHIFT]; } + elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & MASK); } + + elt_t elts[ELTS]; /* XXX 8kb */ + + ASSERT_STATIC (sizeof (elt_t) * 8 == BITS); + ASSERT_STATIC (sizeof (elt_t) * 8 * ELTS > MAX_G); +}; + +struct hb_frozen_set_t +{ + static const unsigned int SHIFT = hb_set_t::SHIFT; + static const unsigned int BITS = hb_set_t::BITS; + static const unsigned int MASK = hb_set_t::MASK; + typedef hb_set_t::elt_t elt_t; + + inline void init (const hb_set_t &set) + { + start = count = 0; + elts = NULL; + + unsigned int max = set.get_max (); + if (max == set.INVALID) + return; + unsigned int min = set.get_min (); + const elt_t &min_elt = set.elt (min); + + start = min & ~MASK; + count = max - start + 1; + unsigned int num_elts = (count + BITS - 1) / BITS; + unsigned int elts_size = num_elts * sizeof (elt_t); + elts = (elt_t *) malloc (elts_size); + if (unlikely (!elts)) + { + start = count = 0; + return; + } + memcpy (elts, &min_elt, elts_size); + } + + inline void fini (void) + { + if (elts) + free (elts); + } + + inline bool has (hb_codepoint_t g) const + { + /* hb_codepoint_t is unsigned. */ + g -= start; + if (unlikely (g > count)) return false; + return !!(elt (g) & mask (g)); + } + + elt_t const &elt (hb_codepoint_t g) const { return elts[g >> SHIFT]; } + elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & MASK); } + + private: + hb_codepoint_t start, count; + elt_t *elts; +}; + + +#endif /* HB_SET_PRIVATE_HH */ |