BLI_vector_set_slots.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once

 
#include <cstdint>
#include <type_traits>
 
namespace blender {

template<typename Key, typename IndexT = int64_t> class SimpleVectorSetSlot {
  static_assert(std::is_integral_v<IndexT> && std::is_signed_v<IndexT>);
 
 private:
#define s_is_empty -1
#define s_is_removed -2

  IndexT state_ = s_is_empty;
 
 public:
  bool is_occupied() const
  {
    return state_ >= 0;
  }

  bool is_empty() const
  {
    return state_ == s_is_empty;
  }

  IndexT index() const
  {
    BLI_assert(this->is_occupied());
    return state_;
  }

  template<typename ForwardKey, typename IsEqual>
  bool contains(const ForwardKey &key,
                const IsEqual &is_equal,
                uint64_t /*hash*/,
                const Key *keys) const
  {
    if (state_ >= 0) {
      return is_equal(key, keys[state_]);
    }
    return false;
  }

  void occupy(IndexT index, uint64_t /*hash*/)
  {
    BLI_assert(!this->is_occupied());
    state_ = index;
  }

  void update_index(IndexT index)
  {
    BLI_assert(this->is_occupied());
    state_ = index;
  }

  void remove()
  {
    BLI_assert(this->is_occupied());
    state_ = s_is_removed;
  }

  bool has_index(IndexT index) const
  {
    return state_ == index;
  }

  template<typename Hash> uint64_t get_hash(const Key &key, const Hash &hash) const
  {
    BLI_assert(this->is_occupied());
    return hash(key);
  }
 
#undef s_is_empty
#undef s_is_removed
};
 
template<typename Key> struct DefaultVectorSetSlot;
 
template<typename Key> struct DefaultVectorSetSlot {
  using type = SimpleVectorSetSlot<Key>;
};
 
}  // namespace blender