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Diffstat (limited to 'src/hb-map-private.hh')
| -rw-r--r-- | src/hb-map-private.hh | 255 |
1 files changed, 0 insertions, 255 deletions
diff --git a/src/hb-map-private.hh b/src/hb-map-private.hh deleted file mode 100644 index d3d4dde..0000000 --- a/src/hb-map-private.hh +++ /dev/null @@ -1,255 +0,0 @@ -/* - * Copyright © 2018 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_MAP_PRIVATE_HH -#define HB_MAP_PRIVATE_HH - -#include "hb-private.hh" -#include "hb-object-private.hh" - - -template <typename T> -inline uint32_t Hash (const T &v) -{ - /* Knuth's multiplicative method: */ - return (uint32_t) v * 2654435761u; -} - - -/* - * hb_map_t - */ - -struct hb_map_t -{ - struct item_t - { - hb_codepoint_t key; - hb_codepoint_t value; - - inline bool is_unused (void) const { return key == INVALID; } - inline bool is_tombstone (void) const { return key != INVALID && value == INVALID; } - }; - - hb_object_header_t header; - bool successful; /* Allocations successful */ - unsigned int population; /* Not including tombstones. */ - unsigned int occupancy; /* Including tombstones. */ - unsigned int mask; - unsigned int prime; - item_t *items; - - inline void init_shallow (void) - { - successful = true; - population = occupancy = 0; - mask = 0; - prime = 0; - items = nullptr; - } - inline void init (void) - { - hb_object_init (this); - init_shallow (); - } - inline void fini_shallow (void) - { - free (items); - } - inline void fini (void) - { - hb_object_fini (this); - fini_shallow (); - } - - inline bool resize (void) - { - if (unlikely (!successful)) return false; - - unsigned int power = _hb_bit_storage (population * 2 + 8); - unsigned int new_size = 1u << power; - item_t *new_items = (item_t *) malloc ((size_t) new_size * sizeof (item_t)); - if (unlikely (!new_items)) - { - successful = false; - return false; - } - memset (new_items, 0xFF, (size_t) new_size * sizeof (item_t)); - - unsigned int old_size = mask + 1; - item_t *old_items = items; - - /* Switch to new, empty, array. */ - population = occupancy = 0; - mask = new_size - 1; - prime = prime_for (power); - items = new_items; - - /* Insert back old items. */ - if (old_items) - for (unsigned int i = 0; i < old_size; i++) - if (old_items[i].key != INVALID && old_items[i].value != INVALID) - set (old_items[i].key, old_items[i].value); - - free (old_items); - - return true; - } - - inline void set (hb_codepoint_t key, hb_codepoint_t value) - { - if (unlikely (!successful)) return; - if (unlikely (key == INVALID)) return; - if ((occupancy + occupancy / 2) >= mask && !resize ()) return; - unsigned int i = bucket_for (key); - - if (value == INVALID && items[i].key != key) - return; /* Trying to delete non-existent key. */ - - if (!items[i].is_unused ()) - { - occupancy--; - if (items[i].is_tombstone ()) - population--; - } - - items[i].key = key; - items[i].value = value; - - occupancy++; - if (!items[i].is_tombstone ()) - population++; - - } - inline hb_codepoint_t get (hb_codepoint_t key) const - { - if (unlikely (!items)) return INVALID; - unsigned int i = bucket_for (key); - return items[i].key == key ? items[i].value : INVALID; - } - - inline void del (hb_codepoint_t key) - { - set (key, INVALID); - } - inline bool has (hb_codepoint_t key) const - { - return get (key) != INVALID; - } - - inline hb_codepoint_t operator [] (unsigned int key) const - { return get (key); } - - static const hb_codepoint_t INVALID = HB_MAP_VALUE_INVALID; - - inline void clear (void) - { - memset (items, 0xFF, ((size_t) mask + 1) * sizeof (item_t)); - population = occupancy = 0; - } - - inline bool is_empty (void) const - { - return population != 0; - } - - inline unsigned int get_population () const - { - return population; - } - - protected: - - inline unsigned int bucket_for (hb_codepoint_t key) const - { - unsigned int i = Hash (key) % prime; - unsigned int step = 0; - unsigned int tombstone = INVALID; - while (!items[i].is_unused ()) - { - if (items[i].key == key) - return i; - if (tombstone == INVALID && items[i].is_tombstone ()) - tombstone = i; - i = (i + ++step) & mask; - } - return tombstone == INVALID ? i : tombstone; - } - - static inline unsigned int prime_for (unsigned int shift) - { - /* Following comment and table copied from glib. */ - /* Each table size has an associated prime modulo (the first prime - * lower than the table size) used to find the initial bucket. Probing - * then works modulo 2^n. The prime modulo is necessary to get a - * good distribution with poor hash functions. - */ - /* Not declaring static to make all kinds of compilers happy... */ - /*static*/ const unsigned int prime_mod [32] = - { - 1, /* For 1 << 0 */ - 2, - 3, - 7, - 13, - 31, - 61, - 127, - 251, - 509, - 1021, - 2039, - 4093, - 8191, - 16381, - 32749, - 65521, /* For 1 << 16 */ - 131071, - 262139, - 524287, - 1048573, - 2097143, - 4194301, - 8388593, - 16777213, - 33554393, - 67108859, - 134217689, - 268435399, - 536870909, - 1073741789, - 2147483647 /* For 1 << 31 */ - }; - - if (unlikely (shift >= ARRAY_LENGTH (prime_mod))) - return prime_mod[ARRAY_LENGTH (prime_mod) - 1]; - - return prime_mod[shift]; - } -}; - - -#endif /* HB_MAP_PRIVATE_HH */ |