BLI_map.hh

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/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
 
#pragma once
 
#include <optional>
#include <unordered_map>
 
#include "BLI_array.hh"
#include "BLI_hash.hh"
#include "BLI_hash_tables.hh"
#include "BLI_map_slots.hh"
#include "BLI_probing_strategies.hh"
 
namespace blender {
 
template<
    typename Key,
    typename Value,
    int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(Key) + sizeof(Value)),
    typename ProbingStrategy = DefaultProbingStrategy,
    typename Hash = DefaultHash<Key>,
    typename IsEqual = DefaultEquality,
    typename Slot = typename DefaultMapSlot<Key, Value>::type,
    typename Allocator = GuardedAllocator>
class Map {
 public:
  using size_type = int64_t;
 
 private:
  int64_t removed_slots_;
  int64_t occupied_and_removed_slots_;
 
  int64_t usable_slots_;
 
  uint64_t slot_mask_;
 
  Hash hash_;
 
  IsEqual is_equal_;
 
#define LOAD_FACTOR 1, 2
  LoadFactor max_load_factor_ = LoadFactor(LOAD_FACTOR);
  using SlotArray =
      Array<Slot, LoadFactor::compute_total_slots(InlineBufferCapacity, LOAD_FACTOR), Allocator>;
#undef LOAD_FACTOR
 
  SlotArray slots_;
 
#define MAP_SLOT_PROBING_BEGIN(HASH, R_SLOT) \
  SLOT_PROBING_BEGIN (ProbingStrategy, HASH, slot_mask_, SLOT_INDEX) \
    auto &R_SLOT = slots_[SLOT_INDEX];
#define MAP_SLOT_PROBING_END() SLOT_PROBING_END()
 
 public:
  Map(Allocator allocator = {}) noexcept
      : removed_slots_(0),
        occupied_and_removed_slots_(0),
        usable_slots_(0),
        slot_mask_(0),
        hash_(),
        is_equal_(),
        slots_(1, allocator)
  {
  }
 
  Map(NoExceptConstructor, Allocator allocator = {}) noexcept : Map(allocator)
  {
  }
 
  ~Map() = default;
 
  Map(const Map &other) = default;
 
  Map(Map &&other) noexcept(std::is_nothrow_move_constructible_v<SlotArray>)
      : Map(NoExceptConstructor(), other.slots_.allocator())
  {
    if constexpr (std::is_nothrow_move_constructible_v<SlotArray>) {
      slots_ = std::move(other.slots_);
    }
    else {
      try {
        slots_ = std::move(other.slots_);
      }
      catch (...) {
        other.noexcept_reset();
        throw;
      }
    }
    removed_slots_ = other.removed_slots_;
    occupied_and_removed_slots_ = other.occupied_and_removed_slots_;
    usable_slots_ = other.usable_slots_;
    slot_mask_ = other.slot_mask_;
    hash_ = std::move(other.hash_);
    is_equal_ = std::move(other.is_equal_);
    other.noexcept_reset();
  }
 
  Map &operator=(const Map &other)
  {
    return copy_assign_container(*this, other);
  }
 
  Map &operator=(Map &&other)
  {
    return move_assign_container(*this, std::move(other));
  }
 
  void add_new(const Key &key, const Value &value)
  {
    this->add_new_as(key, value);
  }
  void add_new(const Key &key, Value &&value)
  {
    this->add_new_as(key, std::move(value));
  }
  void add_new(Key &&key, const Value &value)
  {
    this->add_new_as(std::move(key), value);
  }
  void add_new(Key &&key, Value &&value)
  {
    this->add_new_as(std::move(key), std::move(value));
  }
  template<typename ForwardKey, typename ForwardValue>
  void add_new_as(ForwardKey &&key, ForwardValue &&value)
  {
    this->add_new__impl(
        std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash_(key));
  }
 
  bool add(const Key &key, const Value &value)
  {
    return this->add_as(key, value);
  }
  bool add(const Key &key, Value &&value)
  {
    return this->add_as(key, std::move(value));
  }
  bool add(Key &&key, const Value &value)
  {
    return this->add_as(std::move(key), value);
  }
  bool add(Key &&key, Value &&value)
  {
    return this->add_as(std::move(key), std::move(value));
  }
  template<typename ForwardKey, typename ForwardValue>
  bool add_as(ForwardKey &&key, ForwardValue &&value)
  {
    return this->add__impl(
        std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash_(key));
  }
 
  bool add_overwrite(const Key &key, const Value &value)
  {
    return this->add_overwrite_as(key, value);
  }
  bool add_overwrite(const Key &key, Value &&value)
  {
    return this->add_overwrite_as(key, std::move(value));
  }
  bool add_overwrite(Key &&key, const Value &value)
  {
    return this->add_overwrite_as(std::move(key), value);
  }
  bool add_overwrite(Key &&key, Value &&value)
  {
    return this->add_overwrite_as(std::move(key), std::move(value));
  }
  template<typename ForwardKey, typename ForwardValue>
  bool add_overwrite_as(ForwardKey &&key, ForwardValue &&value)
  {
    return this->add_overwrite__impl(
        std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash_(key));
  }
 
  bool contains(const Key &key) const
  {
    return this->contains_as(key);
  }
  template<typename ForwardKey> bool contains_as(const ForwardKey &key) const
  {
    return this->lookup_slot_ptr(key, hash_(key)) != nullptr;
  }
 
  bool remove(const Key &key)
  {
    return this->remove_as(key);
  }
  template<typename ForwardKey> bool remove_as(const ForwardKey &key)
  {
    Slot *slot = this->lookup_slot_ptr(key, hash_(key));
    if (slot == nullptr) {
      return false;
    }
    slot->remove();
    removed_slots_++;
    return true;
  }
 
  void remove_contained(const Key &key)
  {
    this->remove_contained_as(key);
  }
  template<typename ForwardKey> void remove_contained_as(const ForwardKey &key)
  {
    Slot &slot = this->lookup_slot(key, hash_(key));
    slot.remove();
    removed_slots_++;
  }
 
  Value pop(const Key &key)
  {
    return this->pop_as(key);
  }
  template<typename ForwardKey> Value pop_as(const ForwardKey &key)
  {
    Slot &slot = this->lookup_slot(key, hash_(key));
    Value value = std::move(*slot.value());
    slot.remove();
    removed_slots_++;
    return value;
  }
 
  std::optional<Value> pop_try(const Key &key)
  {
    return this->pop_try_as(key);
  }
  template<typename ForwardKey> std::optional<Value> pop_try_as(const ForwardKey &key)
  {
    Slot *slot = this->lookup_slot_ptr(key, hash_(key));
    if (slot == nullptr) {
      return {};
    }
    std::optional<Value> value = std::move(*slot->value());
    slot->remove();
    removed_slots_++;
    return value;
  }
 
  Value pop_default(const Key &key, const Value &default_value)
  {
    return this->pop_default_as(key, default_value);
  }
  Value pop_default(const Key &key, Value &&default_value)
  {
    return this->pop_default_as(key, std::move(default_value));
  }
  template<typename ForwardKey, typename ForwardValue>
  Value pop_default_as(const ForwardKey &key, ForwardValue &&default_value)
  {
    Slot *slot = this->lookup_slot_ptr(key, hash_(key));
    if (slot == nullptr) {
      return std::forward<ForwardValue>(default_value);
    }
    Value value = std::move(*slot->value());
    slot->remove();
    removed_slots_++;
    return value;
  }
 
  template<typename CreateValueF, typename ModifyValueF>
  auto add_or_modify(const Key &key,
                     const CreateValueF &create_value,
                     const ModifyValueF &modify_value) -> decltype(create_value(nullptr))
  {
    return this->add_or_modify_as(key, create_value, modify_value);
  }
  template<typename CreateValueF, typename ModifyValueF>
  auto add_or_modify(Key &&key, const CreateValueF &create_value, const ModifyValueF &modify_value)
      -> decltype(create_value(nullptr))
  {
    return this->add_or_modify_as(std::move(key), create_value, modify_value);
  }
  template<typename ForwardKey, typename CreateValueF, typename ModifyValueF>
  auto add_or_modify_as(ForwardKey &&key,
                        const CreateValueF &create_value,
                        const ModifyValueF &modify_value) -> decltype(create_value(nullptr))
  {
    return this->add_or_modify__impl(
        std::forward<ForwardKey>(key), create_value, modify_value, hash_(key));
  }
 
  const Value *lookup_ptr(const Key &key) const
  {
    return this->lookup_ptr_as(key);
  }
  Value *lookup_ptr(const Key &key)
  {
    return this->lookup_ptr_as(key);
  }
  template<typename ForwardKey> const Value *lookup_ptr_as(const ForwardKey &key) const
  {
    const Slot *slot = this->lookup_slot_ptr(key, hash_(key));
    return (slot != nullptr) ? slot->value() : nullptr;
  }
  template<typename ForwardKey> Value *lookup_ptr_as(const ForwardKey &key)
  {
    return const_cast<Value *>(const_cast<const Map *>(this)->lookup_ptr_as(key));
  }
 
  const Value &lookup(const Key &key) const
  {
    return this->lookup_as(key);
  }
  Value &lookup(const Key &key)
  {
    return this->lookup_as(key);
  }
  template<typename ForwardKey> const Value &lookup_as(const ForwardKey &key) const
  {
    const Value *ptr = this->lookup_ptr_as(key);
    BLI_assert(ptr != nullptr);
    return *ptr;
  }
  template<typename ForwardKey> Value &lookup_as(const ForwardKey &key)
  {
    Value *ptr = this->lookup_ptr_as(key);
    BLI_assert(ptr != nullptr);
    return *ptr;
  }
 
  Value lookup_default(const Key &key, const Value &default_value) const
  {
    return this->lookup_default_as(key, default_value);
  }
  template<typename ForwardKey, typename ForwardValue>
  Value lookup_default_as(const ForwardKey &key, ForwardValue &&default_value) const
  {
    const Value *ptr = this->lookup_ptr_as(key);
    if (ptr != nullptr) {
      return *ptr;
    }
    else {
      return std::forward<ForwardValue>(default_value);
    }
  }
 
  Value &lookup_or_add(const Key &key, const Value &value)
  {
    return this->lookup_or_add_as(key, value);
  }
  Value &lookup_or_add(const Key &key, Value &&value)
  {
    return this->lookup_or_add_as(key, std::move(value));
  }
  Value &lookup_or_add(Key &&key, const Value &value)
  {
    return this->lookup_or_add_as(std::move(key), value);
  }
  Value &lookup_or_add(Key &&key, Value &&value)
  {
    return this->lookup_or_add_as(std::move(key), std::move(value));
  }
  template<typename ForwardKey, typename ForwardValue>
  Value &lookup_or_add_as(ForwardKey &&key, ForwardValue &&value)
  {
    return this->lookup_or_add__impl(
        std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash_(key));
  }
 
  template<typename CreateValueF>
  Value &lookup_or_add_cb(const Key &key, const CreateValueF &create_value)
  {
    return this->lookup_or_add_cb_as(key, create_value);
  }
  template<typename CreateValueF>
  Value &lookup_or_add_cb(Key &&key, const CreateValueF &create_value)
  {
    return this->lookup_or_add_cb_as(std::move(key), create_value);
  }
  template<typename ForwardKey, typename CreateValueF>
  Value &lookup_or_add_cb_as(ForwardKey &&key, const CreateValueF &create_value)
  {
    return this->lookup_or_add_cb__impl(std::forward<ForwardKey>(key), create_value, hash_(key));
  }
 
  Value &lookup_or_add_default(const Key &key)
  {
    return this->lookup_or_add_default_as(key);
  }
  Value &lookup_or_add_default(Key &&key)
  {
    return this->lookup_or_add_default_as(std::move(key));
  }
  template<typename ForwardKey> Value &lookup_or_add_default_as(ForwardKey &&key)
  {
    return this->lookup_or_add_cb_as(std::forward<ForwardKey>(key), []() { return Value(); });
  }
 
  template<typename FuncT> void foreach_item(const FuncT &func) const
  {
    int64_t size = slots_.size();
    for (int64_t i = 0; i < size; i++) {
      const Slot &slot = slots_[i];
      if (slot.is_occupied()) {
        const Key &key = *slot.key();
        const Value &value = *slot.value();
        func(key, value);
      }
    }
  }
 
  template<typename SubIterator> struct BaseIterator {
    using iterator_category = std::forward_iterator_tag;
    using difference_type = std::ptrdiff_t;
 
    Slot *slots_;
    int64_t total_slots_;
    int64_t current_slot_;
 
    BaseIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : slots_(const_cast<Slot *>(slots)), total_slots_(total_slots), current_slot_(current_slot)
    {
    }
 
    BaseIterator &operator++()
    {
      while (++current_slot_ < total_slots_) {
        if (slots_[current_slot_].is_occupied()) {
          break;
        }
      }
      return *this;
    }
 
    BaseIterator operator++(int) const
    {
      BaseIterator copied_iterator = *this;
      ++copied_iterator;
      return copied_iterator;
    }
 
    friend bool operator!=(const BaseIterator &a, const BaseIterator &b)
    {
      BLI_assert(a.slots_ == b.slots_);
      BLI_assert(a.total_slots_ == b.total_slots_);
      return a.current_slot_ != b.current_slot_;
    }
 
    friend bool operator==(const BaseIterator &a, const BaseIterator &b)
    {
      return !(a != b);
    }
 
    SubIterator begin() const
    {
      for (int64_t i = 0; i < total_slots_; i++) {
        if (slots_[i].is_occupied()) {
          return SubIterator(slots_, total_slots_, i);
        }
      }
      return this->end();
    }
 
    SubIterator end() const
    {
      return SubIterator(slots_, total_slots_, total_slots_);
    }
 
    Slot &current_slot() const
    {
      return slots_[current_slot_];
    }
  };
 
  class KeyIterator final : public BaseIterator<KeyIterator> {
   public:
    using value_type = Key;
    using pointer = const Key *;
    using reference = const Key &;
 
    KeyIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : BaseIterator<KeyIterator>(slots, total_slots, current_slot)
    {
    }
 
    const Key &operator*() const
    {
      return *this->current_slot().key();
    }
  };
 
  class ValueIterator final : public BaseIterator<ValueIterator> {
   public:
    using value_type = Value;
    using pointer = const Value *;
    using reference = const Value &;
 
    ValueIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : BaseIterator<ValueIterator>(slots, total_slots, current_slot)
    {
    }
 
    const Value &operator*() const
    {
      return *this->current_slot().value();
    }
  };
 
  class MutableValueIterator final : public BaseIterator<MutableValueIterator> {
   public:
    using value_type = Value;
    using pointer = Value *;
    using reference = Value &;
 
    MutableValueIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : BaseIterator<MutableValueIterator>(slots, total_slots, current_slot)
    {
    }
 
    Value &operator*()
    {
      return *this->current_slot().value();
    }
  };
 
  struct Item {
    const Key &key;
    const Value &value;
  };
 
  struct MutableItem {
    const Key &key;
    Value &value;
 
    operator Item() const
    {
      return Item{key, value};
    }
  };
 
  class ItemIterator final : public BaseIterator<ItemIterator> {
   public:
    using value_type = Item;
    using pointer = Item *;
    using reference = Item &;
 
    ItemIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : BaseIterator<ItemIterator>(slots, total_slots, current_slot)
    {
    }
 
    Item operator*() const
    {
      const Slot &slot = this->current_slot();
      return {*slot.key(), *slot.value()};
    }
  };
 
  class MutableItemIterator final : public BaseIterator<MutableItemIterator> {
   public:
    using value_type = MutableItem;
    using pointer = MutableItem *;
    using reference = MutableItem &;
 
    MutableItemIterator(const Slot *slots, int64_t total_slots, int64_t current_slot)
        : BaseIterator<MutableItemIterator>(slots, total_slots, current_slot)
    {
    }
 
    MutableItem operator*() const
    {
      Slot &slot = this->current_slot();
      return {*slot.key(), *slot.value()};
    }
  };
 
  KeyIterator keys() const
  {
    return KeyIterator(slots_.data(), slots_.size(), 0);
  }
 
  ValueIterator values() const
  {
    return ValueIterator(slots_.data(), slots_.size(), 0);
  }
 
  MutableValueIterator values()
  {
    return MutableValueIterator(slots_.data(), slots_.size(), 0);
  }
 
  ItemIterator items() const
  {
    return ItemIterator(slots_.data(), slots_.size(), 0);
  }
 
  MutableItemIterator items()
  {
    return MutableItemIterator(slots_.data(), slots_.size(), 0);
  }
 
  void print_stats(StringRef name = "") const
  {
    HashTableStats stats(*this, this->keys());
    stats.print(name);
  }
 
  int64_t size() const
  {
    return occupied_and_removed_slots_ - removed_slots_;
  }
 
  bool is_empty() const
  {
    return occupied_and_removed_slots_ == removed_slots_;
  }
 
  int64_t capacity() const
  {
    return slots_.size();
  }
 
  int64_t removed_amount() const
  {
    return removed_slots_;
  }
 
  int64_t size_per_element() const
  {
    return sizeof(Slot);
  }
 
  int64_t size_in_bytes() const
  {
    return static_cast<int64_t>(sizeof(Slot) * slots_.size());
  }
 
  void reserve(int64_t n)
  {
    if (usable_slots_ < n) {
      this->realloc_and_reinsert(n);
    }
  }
 
  void clear()
  {
    this->noexcept_reset();
  }
 
  int64_t count_collisions(const Key &key) const
  {
    return this->count_collisions__impl(key, hash_(key));
  }
 
 private:
  BLI_NOINLINE void realloc_and_reinsert(int64_t min_usable_slots)
  {
    int64_t total_slots, usable_slots;
    max_load_factor_.compute_total_and_usable_slots(
        SlotArray::inline_buffer_capacity(), min_usable_slots, &total_slots, &usable_slots);
    BLI_assert(total_slots >= 1);
    const uint64_t new_slot_mask = static_cast<uint64_t>(total_slots) - 1;
 
    if (this->size() == 0) {
      try {
        slots_.reinitialize(total_slots);
      }
      catch (...) {
        this->noexcept_reset();
        throw;
      }
      removed_slots_ = 0;
      occupied_and_removed_slots_ = 0;
      usable_slots_ = usable_slots;
      slot_mask_ = new_slot_mask;
      return;
    }
 
    SlotArray new_slots(total_slots);
 
    try {
      for (Slot &slot : slots_) {
        if (slot.is_occupied()) {
          this->add_after_grow(slot, new_slots, new_slot_mask);
          slot.remove();
        }
      }
      slots_ = std::move(new_slots);
    }
    catch (...) {
      this->noexcept_reset();
      throw;
    }
 
    occupied_and_removed_slots_ -= removed_slots_;
    usable_slots_ = usable_slots;
    removed_slots_ = 0;
    slot_mask_ = new_slot_mask;
  }
 
  void add_after_grow(Slot &old_slot, SlotArray &new_slots, uint64_t new_slot_mask)
  {
    uint64_t hash = old_slot.get_hash(Hash());
    SLOT_PROBING_BEGIN (ProbingStrategy, hash, new_slot_mask, slot_index) {
      Slot &slot = new_slots[slot_index];
      if (slot.is_empty()) {
        slot.occupy(std::move(*old_slot.key()), std::move(*old_slot.value()), hash);
        return;
      }
    }
    SLOT_PROBING_END();
  }
 
  void noexcept_reset() noexcept
  {
    Allocator allocator = slots_.allocator();
    this->~Map();
    new (this) Map(NoExceptConstructor(), allocator);
  }
 
  template<typename ForwardKey, typename ForwardValue>
  void add_new__impl(ForwardKey &&key, ForwardValue &&value, uint64_t hash)
  {
    BLI_assert(!this->contains_as(key));
 
    this->ensure_can_add();
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.is_empty()) {
        slot.occupy(std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash);
        occupied_and_removed_slots_++;
        return;
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey, typename ForwardValue>
  bool add__impl(ForwardKey &&key, ForwardValue &&value, uint64_t hash)
  {
    this->ensure_can_add();
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.is_empty()) {
        slot.occupy(std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash);
        occupied_and_removed_slots_++;
        return true;
      }
      if (slot.contains(key, is_equal_, hash)) {
        return false;
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey, typename CreateValueF, typename ModifyValueF>
  auto add_or_modify__impl(ForwardKey &&key,
                           const CreateValueF &create_value,
                           const ModifyValueF &modify_value,
                           uint64_t hash) -> decltype(create_value(nullptr))
  {
    using CreateReturnT = decltype(create_value(nullptr));
    using ModifyReturnT = decltype(modify_value(nullptr));
    BLI_STATIC_ASSERT((std::is_same_v<CreateReturnT, ModifyReturnT>),
                      "Both callbacks should return the same type.");
 
    this->ensure_can_add();
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.is_empty()) {
        Value *value_ptr = slot.value();
        if constexpr (std::is_void_v<CreateReturnT>) {
          create_value(value_ptr);
          slot.occupy_no_value(std::forward<ForwardKey>(key), hash);
          occupied_and_removed_slots_++;
          return;
        }
        else {
          auto &&return_value = create_value(value_ptr);
          slot.occupy_no_value(std::forward<ForwardKey>(key), hash);
          occupied_and_removed_slots_++;
          return return_value;
        }
      }
      if (slot.contains(key, is_equal_, hash)) {
        Value *value_ptr = slot.value();
        return modify_value(value_ptr);
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey, typename CreateValueF>
  Value &lookup_or_add_cb__impl(ForwardKey &&key, const CreateValueF &create_value, uint64_t hash)
  {
    this->ensure_can_add();
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.is_empty()) {
        slot.occupy(std::forward<ForwardKey>(key), create_value(), hash);
        occupied_and_removed_slots_++;
        return *slot.value();
      }
      if (slot.contains(key, is_equal_, hash)) {
        return *slot.value();
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey, typename ForwardValue>
  Value &lookup_or_add__impl(ForwardKey &&key, ForwardValue &&value, uint64_t hash)
  {
    this->ensure_can_add();
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.is_empty()) {
        slot.occupy(std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash);
        occupied_and_removed_slots_++;
        return *slot.value();
      }
      if (slot.contains(key, is_equal_, hash)) {
        return *slot.value();
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey, typename ForwardValue>
  bool add_overwrite__impl(ForwardKey &&key, ForwardValue &&value, uint64_t hash)
  {
    auto create_func = [&](Value *ptr) {
      new (static_cast<void *>(ptr)) Value(std::forward<ForwardValue>(value));
      return true;
    };
    auto modify_func = [&](Value *ptr) {
      *ptr = std::forward<ForwardValue>(value);
      return false;
    };
    return this->add_or_modify__impl(
        std::forward<ForwardKey>(key), create_func, modify_func, hash);
  }
 
  template<typename ForwardKey>
  const Slot &lookup_slot(const ForwardKey &key, const uint64_t hash) const
  {
    BLI_assert(this->contains_as(key));
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.contains(key, is_equal_, hash)) {
        return slot;
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey> Slot &lookup_slot(const ForwardKey &key, const uint64_t hash)
  {
    return const_cast<Slot &>(const_cast<const Map *>(this)->lookup_slot(key, hash));
  }
 
  template<typename ForwardKey>
  const Slot *lookup_slot_ptr(const ForwardKey &key, const uint64_t hash) const
  {
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.contains(key, is_equal_, hash)) {
        return &slot;
      }
      if (slot.is_empty()) {
        return nullptr;
      }
    }
    MAP_SLOT_PROBING_END();
  }
 
  template<typename ForwardKey> Slot *lookup_slot_ptr(const ForwardKey &key, const uint64_t hash)
  {
    return const_cast<Slot *>(const_cast<const Map *>(this)->lookup_slot_ptr(key, hash));
  }
 
  template<typename ForwardKey>
  int64_t count_collisions__impl(const ForwardKey &key, uint64_t hash) const
  {
    int64_t collisions = 0;
 
    MAP_SLOT_PROBING_BEGIN (hash, slot) {
      if (slot.contains(key, is_equal_, hash)) {
        return collisions;
      }
      if (slot.is_empty()) {
        return collisions;
      }
      collisions++;
    }
    MAP_SLOT_PROBING_END();
  }
 
  void ensure_can_add()
  {
    if (occupied_and_removed_slots_ >= usable_slots_) {
      this->realloc_and_reinsert(this->size() + 1);
      BLI_assert(occupied_and_removed_slots_ < usable_slots_);
    }
  }
};
 
template<typename Key,
         typename Value,
         int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(Key) +
                                                                       sizeof(Value)),
         typename ProbingStrategy = DefaultProbingStrategy,
         typename Hash = DefaultHash<Key>,
         typename IsEqual = DefaultEquality,
         typename Slot = typename DefaultMapSlot<Key, Value>::type>
using RawMap =
    Map<Key, Value, InlineBufferCapacity, ProbingStrategy, Hash, IsEqual, Slot, RawAllocator>;
 
template<typename Key, typename Value> class StdUnorderedMapWrapper {
 private:
  using MapType = std::unordered_map<Key, Value, blender::DefaultHash<Key>>;
  MapType map_;
 
 public:
  int64_t size() const
  {
    return static_cast<int64_t>(map_.size());
  }
 
  bool is_empty() const
  {
    return map_.empty();
  }
 
  void reserve(int64_t n)
  {
    map_.reserve(n);
  }
 
  template<typename ForwardKey, typename ForwardValue>
  void add_new(ForwardKey &&key, ForwardValue &&value)
  {
    map_.insert({std::forward<ForwardKey>(key), std::forward<ForwardValue>(value)});
  }
 
  template<typename ForwardKey, typename ForwardValue>
  bool add(ForwardKey &&key, ForwardValue &&value)
  {
    return map_.insert({std::forward<ForwardKey>(key), std::forward<ForwardValue>(value)}).second;
  }
 
  bool contains(const Key &key) const
  {
    return map_.find(key) != map_.end();
  }
 
  bool remove(const Key &key)
  {
    return (bool)map_.erase(key);
  }
 
  Value &lookup(const Key &key)
  {
    return map_.find(key)->second;
  }
 
  const Value &lookup(const Key &key) const
  {
    return map_.find(key)->second;
  }
 
  void clear()
  {
    map_.clear();
  }
 
  void print_stats(StringRef UNUSED(name) = "") const
  {
  }
};
 
}  // namespace blender