480 lines
12 KiB
C++
480 lines
12 KiB
C++
/*
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* Copyright © 2018 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Behdad Esfahbod
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*/
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#ifndef HB_MAP_HH
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#define HB_MAP_HH
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#include "hb.hh"
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/*
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* hb_hashmap_t
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*/
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extern HB_INTERNAL const hb_codepoint_t minus_1;
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template <typename K, typename V,
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bool minus_one = false>
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struct hb_hashmap_t
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{
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hb_hashmap_t () { init (); }
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~hb_hashmap_t () { fini (); }
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hb_hashmap_t (const hb_hashmap_t& o) : hb_hashmap_t () { resize (population); hb_copy (o, *this); }
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hb_hashmap_t (hb_hashmap_t&& o) : hb_hashmap_t () { hb_swap (*this, o); }
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hb_hashmap_t& operator= (const hb_hashmap_t& o) { resize (population); hb_copy (o, *this); return *this; }
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hb_hashmap_t& operator= (hb_hashmap_t&& o) { hb_swap (*this, o); return *this; }
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hb_hashmap_t (std::initializer_list<hb_pair_t<K, V>> lst) : hb_hashmap_t ()
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{
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for (auto&& item : lst)
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set (item.first, item.second);
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}
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template <typename Iterable,
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hb_requires (hb_is_iterable (Iterable))>
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hb_hashmap_t (const Iterable &o) : hb_hashmap_t ()
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{
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auto iter = hb_iter (o);
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if (iter.is_random_access_iterator)
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resize (hb_len (iter));
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hb_copy (iter, *this);
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}
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struct item_t
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{
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K key;
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uint32_t hash : 30;
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uint32_t is_used_ : 1;
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uint32_t is_tombstone_ : 1;
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V value;
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bool is_used () const { return is_used_; }
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void set_used (bool is_used) { is_used_ = is_used; }
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bool is_tombstone () const { return is_tombstone_; }
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void set_tombstone (bool is_tombstone) { is_tombstone_ = is_tombstone; }
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bool is_real () const { return is_used_ && !is_tombstone_; }
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template <bool v = minus_one,
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hb_enable_if (v == false)>
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static inline const V& default_value () { return Null(V); };
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template <bool v = minus_one,
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hb_enable_if (v == true)>
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static inline const V& default_value ()
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{
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static_assert (hb_is_same (V, hb_codepoint_t), "");
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return minus_1;
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};
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void clear ()
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{
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new (std::addressof (key)) K ();
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new (std::addressof (value)) V ();
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hash = 0;
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is_used_ = false;
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is_tombstone_ = false;
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}
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bool operator == (const K &o) { return hb_deref (key) == hb_deref (o); }
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bool operator == (const item_t &o) { return *this == o.key; }
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hb_pair_t<K, V> get_pair() const { return hb_pair_t<K, V> (key, value); }
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hb_pair_t<const K &, const V &> get_pair_ref() const { return hb_pair_t<const K &, const V &> (key, value); }
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uint32_t total_hash () const
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{ return (hash * 31) + hb_hash (value); }
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};
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hb_object_header_t header;
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bool successful; /* Allocations successful */
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unsigned int population; /* Not including tombstones. */
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unsigned int occupancy; /* Including tombstones. */
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unsigned int mask;
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unsigned int prime;
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item_t *items;
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friend void swap (hb_hashmap_t& a, hb_hashmap_t& b)
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{
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if (unlikely (!a.successful || !b.successful))
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return;
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hb_swap (a.population, b.population);
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hb_swap (a.occupancy, b.occupancy);
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hb_swap (a.mask, b.mask);
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hb_swap (a.prime, b.prime);
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hb_swap (a.items, b.items);
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}
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void init ()
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{
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hb_object_init (this);
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successful = true;
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population = occupancy = 0;
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mask = 0;
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prime = 0;
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items = nullptr;
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}
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void fini ()
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{
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hb_object_fini (this);
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if (likely (items)) {
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unsigned size = mask + 1;
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for (unsigned i = 0; i < size; i++)
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items[i].~item_t ();
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hb_free (items);
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items = nullptr;
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}
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population = occupancy = 0;
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}
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void reset ()
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{
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successful = true;
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clear ();
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}
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bool in_error () const { return !successful; }
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bool resize (unsigned new_population = 0)
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{
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if (unlikely (!successful)) return false;
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unsigned int power = hb_bit_storage (hb_max (population, new_population) * 2 + 8);
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unsigned int new_size = 1u << power;
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item_t *new_items = (item_t *) hb_malloc ((size_t) new_size * sizeof (item_t));
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if (unlikely (!new_items))
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{
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successful = false;
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return false;
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}
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for (auto &_ : hb_iter (new_items, new_size))
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_.clear ();
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unsigned int old_size = mask + 1;
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item_t *old_items = items;
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/* Switch to new, empty, array. */
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population = occupancy = 0;
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mask = new_size - 1;
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prime = prime_for (power);
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items = new_items;
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/* Insert back old items. */
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if (old_items)
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for (unsigned int i = 0; i < old_size; i++)
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{
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if (old_items[i].is_real ())
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{
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set_with_hash (old_items[i].key,
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old_items[i].hash,
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std::move (old_items[i].value));
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}
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old_items[i].~item_t ();
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}
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hb_free (old_items);
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return true;
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}
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template <typename VV>
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bool set (K key, VV&& value) { return set_with_hash (key, hb_hash (key), std::forward<VV> (value)); }
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const V& get (K key) const
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{
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if (unlikely (!items)) return item_t::default_value ();
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unsigned int i = bucket_for (key);
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return items[i].is_real () && items[i] == key ? items[i].value : item_t::default_value ();
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}
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void del (K key) { set_with_hash (key, hb_hash (key), item_t::default_value (), true); }
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/* Has interface. */
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typedef const V& value_t;
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value_t operator [] (K k) const { return get (k); }
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template <typename VV=V>
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bool has (K key, VV **vp = nullptr) const
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{
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if (unlikely (!items))
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return false;
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unsigned int i = bucket_for (key);
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if (items[i].is_real () && items[i] == key)
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{
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if (vp) *vp = &items[i].value;
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return true;
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}
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else
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return false;
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}
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/* Projection. */
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V operator () (K k) const { return get (k); }
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void clear ()
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{
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if (unlikely (!successful)) return;
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if (items)
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for (auto &_ : hb_iter (items, mask + 1))
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_.clear ();
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population = occupancy = 0;
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}
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bool is_empty () const { return population == 0; }
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explicit operator bool () const { return !is_empty (); }
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uint32_t hash () const
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{
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uint32_t h = 0;
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for (const auto &item : + hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real))
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h ^= item.total_hash ();
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return h;
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}
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bool is_equal (const hb_hashmap_t &other) const
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{
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if (population != other.population) return false;
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for (auto pair : iter ())
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if (get (pair.first) != pair.second)
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return false;
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return true;
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}
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bool operator == (const hb_hashmap_t &other) const { return is_equal (other); }
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bool operator != (const hb_hashmap_t &other) const { return !is_equal (other); }
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unsigned int get_population () const { return population; }
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/*
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* Iterator
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*/
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auto iter () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::get_pair)
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)
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auto iter_ref () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::get_pair_ref)
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)
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auto keys () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::key)
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| hb_map (hb_ridentity)
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)
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auto keys_ref () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::key)
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)
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auto values () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::value)
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| hb_map (hb_ridentity)
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)
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auto values_ref () const HB_AUTO_RETURN
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(
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+ hb_array (items, mask ? mask + 1 : 0)
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| hb_filter (&item_t::is_real)
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| hb_map (&item_t::value)
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)
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/* Sink interface. */
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hb_hashmap_t& operator << (const hb_pair_t<K, V>& v)
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{ set (v.first, v.second); return *this; }
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protected:
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template <typename VV>
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bool set_with_hash (K key, uint32_t hash, VV&& value, bool is_delete=false)
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{
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if (unlikely (!successful)) return false;
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if (unlikely ((occupancy + occupancy / 2) >= mask && !resize ())) return false;
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unsigned int i = bucket_for_hash (key, hash);
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if (is_delete && items[i].key != key)
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return true; /* Trying to delete non-existent key. */
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if (items[i].is_used ())
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{
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occupancy--;
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if (!items[i].is_tombstone ())
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population--;
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}
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items[i].key = key;
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items[i].value = std::forward<VV> (value);
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items[i].hash = hash;
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items[i].set_used (true);
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items[i].set_tombstone (is_delete);
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occupancy++;
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if (!is_delete)
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population++;
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return true;
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}
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unsigned int bucket_for (const K &key) const
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{
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return bucket_for_hash (key, hb_hash (key));
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}
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unsigned int bucket_for_hash (const K &key, uint32_t hash) const
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{
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hash &= 0x3FFFFFFF; // We only store lower 30bit of hash
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unsigned int i = hash % prime;
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unsigned int step = 0;
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unsigned int tombstone = (unsigned) -1;
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while (items[i].is_used ())
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{
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if (items[i].hash == hash && items[i] == key)
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return i;
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if (tombstone == (unsigned) -1 && items[i].is_tombstone ())
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tombstone = i;
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i = (i + ++step) & mask;
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}
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return tombstone == (unsigned) -1 ? i : tombstone;
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}
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static unsigned int prime_for (unsigned int shift)
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{
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/* Following comment and table copied from glib. */
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/* Each table size has an associated prime modulo (the first prime
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* lower than the table size) used to find the initial bucket. Probing
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* then works modulo 2^n. The prime modulo is necessary to get a
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* good distribution with poor hash functions.
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*/
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/* Not declaring static to make all kinds of compilers happy... */
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/*static*/ const unsigned int prime_mod [32] =
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{
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1, /* For 1 << 0 */
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2,
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3,
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7,
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13,
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31,
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61,
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127,
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251,
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509,
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1021,
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2039,
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4093,
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8191,
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16381,
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32749,
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65521, /* For 1 << 16 */
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131071,
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262139,
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524287,
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1048573,
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2097143,
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4194301,
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8388593,
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16777213,
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33554393,
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67108859,
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134217689,
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268435399,
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536870909,
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1073741789,
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2147483647 /* For 1 << 31 */
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};
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if (unlikely (shift >= ARRAY_LENGTH (prime_mod)))
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return prime_mod[ARRAY_LENGTH (prime_mod) - 1];
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return prime_mod[shift];
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}
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};
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/*
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* hb_map_t
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*/
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struct hb_map_t : hb_hashmap_t<hb_codepoint_t,
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hb_codepoint_t,
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true>
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{
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using hashmap = hb_hashmap_t<hb_codepoint_t,
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hb_codepoint_t,
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true>;
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~hb_map_t () = default;
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hb_map_t () : hashmap () {}
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hb_map_t (const hb_map_t &o) : hashmap ((hashmap &) o) {}
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hb_map_t (hb_map_t &&o) : hashmap (std::move ((hashmap &) o)) {}
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hb_map_t& operator= (const hb_map_t&) = default;
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hb_map_t& operator= (hb_map_t&&) = default;
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hb_map_t (std::initializer_list<hb_pair_t<hb_codepoint_t, hb_codepoint_t>> lst) : hashmap (lst) {}
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template <typename Iterable,
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hb_requires (hb_is_iterable (Iterable))>
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hb_map_t (const Iterable &o) : hashmap (o) {}
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};
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template <typename K, typename V>
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static inline
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hb_hashmap_t<K, V>* hb_hashmap_create ()
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{
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using hashmap = hb_hashmap_t<K, V>;
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hashmap* map;
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if (!(map = hb_object_create<hashmap> ()))
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return nullptr;
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return map;
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}
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template <typename K, typename V>
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static inline
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void hb_hashmap_destroy (hb_hashmap_t<K, V>* map)
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{
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if (!hb_object_destroy (map))
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return;
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hb_free (map);
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}
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namespace hb {
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template <typename K, typename V>
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struct vtable<hb_hashmap_t<K, V>>
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{
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static constexpr auto destroy = hb_hashmap_destroy<K,V>;
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};
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}
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#endif /* HB_MAP_HH */
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