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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.
*/
#ifndef __BLI_MAP_HH__
#define __BLI_MAP_HH__
/** \file
* \ingroup bli
*
* A `blender::Map<Key, Value>` is an unordered associative container that stores key-value pairs.
* The keys have to be unique. It is designed to be a more convenient and efficient replacement for
* `std::unordered_map`. All core operations (add, lookup, remove and contains) can be done in O(1)
* amortized expected time.
*
* Your default choice for a hash map in Blender should be `blender::Map`.
*
* blender::Map is implemented using open addressing in a slot array with a power-of-two size.
* Every slot is in one of three states: empty, occupied or removed. If a slot is occupied, it
* contains a Key and Value instance.
*
* Benchmarking and comparing hash tables is hard, because many factors influence the result. The
* performance of a hash table depends on the combination of the hash function, probing strategy,
* max load factor, data types, slot type and data distribution. This implementation is designed to
* be relatively fast by default in all cases. However, it also offers many customization points
* that allow it to be optimized for a specific use case.
*
* A rudimentary benchmark can be found in BLI_map_test.cc. The results of that benchmark are there
* as well. The numbers show that in this specific case blender::Map outperforms std::unordered_map
* consistently by a good amount.
*
* Some noteworthy information:
* - Key and Value must be movable types.
* - Pointers to keys and values might be invalidated when the map is changed or moved.
* - The hash function can be customized. See BLI_hash.hh for details.
* - The probing strategy can be customized. See BLI_probing_strategies.hh for details.
* - The slot type can be customized. See BLI_map_slots.hh for details.
* - Small buffer optimization is enabled by default, if Key and Value are not too large.
* - The methods `add_new` and `remove_contained` should be used instead of `add` and `remove`
* whenever appropriate. Assumptions and intention are described better this way.
* - There are multiple methods to add and lookup keys for different use cases.
* - You cannot use a range-for loop on the map directly. Instead use the keys(), values() and
* items() iterators. If your map is non-const, you can also change the values through those
* iterators (but not the keys).
* - Lookups can be performed using types other than Key without conversion. For that use the
* methods ending with `_as`. The template parameters Hash and IsEqual have to support the other
* key type. This can greatly improve performance when the map uses strings as keys.
* - The default constructor is cheap, even when a large InlineBufferCapacity is used. A large
* slot array will only be initialized when the first element is added.
* - The `print_stats` method can be used to get information about the distribution of keys and
* memory usage of the map.
* - The method names don't follow the std::unordered_map names in many cases. Searching for such
* names in this file will usually let you discover the new name.
* - There is a StdUnorderedMapWrapper class, that wraps std::unordered_map and gives it the same
* interface as blender::Map. This is useful for benchmarking.
*/
#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<
/**
* Type of the keys stored in the map. Keys have to be movable. Furthermore, the hash and
* is-equal functions have to support it.
*/
typename Key,
/**
* Type of the value that is stored per key. It has to be movable as well.
*/
typename Value,
/**
* The minimum number of elements that can be stored in this Map without doing a heap
* allocation. This is useful when you expect to have many small maps. However, keep in mind
* that (unlike vector) initializing a map has a O(n) cost in the number of slots.
*
* When Key or Value are large, the small buffer optimization is disabled by default to avoid
* large unexpected allocations on the stack. It can still be enabled explicitely though.
*/
uint32_t InlineBufferCapacity = (sizeof(Key) + sizeof(Value) < 100) ? 4 : 0,
/**
* The strategy used to deal with collistions. They are defined in BLI_probing_strategies.hh.
*/
typename ProbingStrategy = DefaultProbingStrategy,
/**
* The hash function used to hash the keys. There is a default for many types. See BLI_hash.hh
* for examples on how to define a custom hash function.
*/
typename Hash = DefaultHash<Key>,
/**
* The equality operator used to compare keys. By default it will simply compare keys using the
* `==` operator.
*/
typename IsEqual = DefaultEquality,
/**
* This is what will actually be stored in the hash table array. At a minimum a slot has to be
* able to hold a key, a value and information about whether the slot is empty, occupied or
* removed. Using a non-standard slot type can improve performance or reduce the memory
* footprint for some types. Slot types are defined in BLI_map_slots.hh
*/
typename Slot = typename DefaultMapSlot<Key, Value>::type,
/**
* The allocator used by this map. Should rarely be changed, except when you don't want that
* MEM_* is used internally.
*/
typename Allocator = GuardedAllocator>
class Map {
private:
/**
* Slots are either empty, occupied or removed. The number of occupied slots can be computed by
* subtracting the removed slots from the occupied-and-removed slots.
*/
uint32_t m_removed_slots;
uint32_t m_occupied_and_removed_slots;
/**
* The maximum number of slots that can be used (either occupied or removed) until the set has to
* grow. This is the total number of slots times the max load factor.
*/
uint32_t m_usable_slots;
/**
* The number of slots minus one. This is a bit mask that can be used to turn any integer into a
* valid slot index efficiently.
*/
uint32_t m_slot_mask;
/** This is called to hash incoming keys. */
Hash m_hash;
/** This is called to check equality of two keys. */
IsEqual m_is_equal;
/** The max load factor is 1/2 = 50% by default. */
#define LOAD_FACTOR 1, 2
LoadFactor m_max_load_factor = LoadFactor(LOAD_FACTOR);
using SlotArray =
Array<Slot, LoadFactor::compute_total_slots(InlineBufferCapacity, LOAD_FACTOR), Allocator>;
#undef LOAD_FACTOR
/**
* This is the array that contains the actual slots. There is always at least one empty slot and
* the size of the array is a power of two.
*/
SlotArray m_slots;
/** Iterate over a slot index sequence for a given hash. */
#define MAP_SLOT_PROBING_BEGIN(HASH, R_SLOT) \
SLOT_PROBING_BEGIN (ProbingStrategy, HASH, m_slot_mask, SLOT_INDEX) \
auto &R_SLOT = m_slots[SLOT_INDEX];
#define MAP_SLOT_PROBING_END() SLOT_PROBING_END()
public:
/**
* Initialize an empty map. This is a cheap operation no matter how large the inline buffer is.
* This is necessary to avoid a high cost when no elements are added at all. An optimized grow
* operation is performed on the first insertion.
*/
Map()
: m_removed_slots(0),
m_occupied_and_removed_slots(0),
m_usable_slots(0),
m_slot_mask(0),
m_hash(),
m_is_equal(),
m_slots(1)
{
}
~Map() = default;
Map(const Map &other) = default;
Map(Map &&other) noexcept
: m_removed_slots(other.m_removed_slots),
m_occupied_and_removed_slots(other.m_occupied_and_removed_slots),
m_usable_slots(other.m_usable_slots),
m_slot_mask(other.m_slot_mask),
m_hash(std::move(other.m_hash)),
m_is_equal(std::move(other.m_is_equal)),
m_slots(std::move(other.m_slots))
{
other.~Map();
new (&other) Map();
}
Map &operator=(const Map &other)
{
if (this == &other) {
return *this;
}
this->~Map();
new (this) Map(other);
return *this;
}
Map &operator=(Map &&other)
{
if (this == &other) {
return *this;
}
this->~Map();
new (this) Map(std::move(other));
return *this;
}
/**
* Insert a new key-value-pair into the map. This invokes undefined behavior when the key is in
* the map already.
*/
void add_new(const Key &key, const Value &value)
{
this->add_new__impl(key, value, m_hash(key));
}
void add_new(const Key &key, Value &&value)
{
this->add_new__impl(key, std::move(value), m_hash(key));
}
void add_new(Key &&key, const Value &value)
{
this->add_new__impl(std::move(key), value, m_hash(key));
}
void add_new(Key &&key, Value &&value)
{
this->add_new__impl(std::move(key), std::move(value), m_hash(key));
}
/**
* Add a key-value-pair to the map. If the map contains the key already, nothing is changed.
* If you want to replace the currently stored value, use `add_overwrite`.
* Returns true when the key has been newly added.
*
* This is similar to std::unordered_map::insert.
*/
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));
}
/**
* Same as `add`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey, typename ForwardValue>
bool add_as(ForwardKey &&key, ForwardValue &&value)
{
return this->add__impl(
std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), m_hash(key));
}
/**
* Adds a key-value-pair to the map. If the map contained the key already, the corresponding
* value will be replaced.
* Returns true when the key has been newly added.
*
* This is similar to std::unordered_map::insert_or_assign.
*/
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));
}
/**
* Same as `add_overwrite`, but accepts other key types that are supported by the hash function.
*/
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), m_hash(key));
}
/**
* Returns true if there is a key in the map that compares equal to the given key.
*
* This is similar to std::unordered_map::contains.
*/
bool contains(const Key &key) const
{
return this->contains_as(key);
}
/**
* Same as `contains`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey> bool contains_as(const ForwardKey &key) const
{
return this->contains__impl(key, m_hash(key));
}
/**
* Deletes the key-value-pair with the given key. Returns true when the key was contained and is
* now removed, otherwise false.
*
* This is similar to std::unordered_map::erase.
*/
bool remove(const Key &key)
{
return this->remove_as(key);
}
/**
* Same as `remove`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey> bool remove_as(const ForwardKey &key)
{
return this->remove__impl(key, m_hash(key));
}
/**
* Deletes the key-value-pair with the given key. This invokes undefined behavior when the key is
* not in the map.
*/
void remove_contained(const Key &key)
{
this->remove_contained_as(key);
}
/**
* Same as `remove_contained`, but accepts other key types that are supported by the hash
* function.
*/
template<typename ForwardKey> void remove_contained_as(const ForwardKey &key)
{
this->remove_contained__impl(key, m_hash(key));
}
/**
* Get the value that is stored for the given key and remove it from the map. This invokes
* undefined behavior when the key is not in the map.
*/
Value pop(const Key &key)
{
return this->pop_as(key);
}
/**
* Same as `pop`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey> Value pop_as(const ForwardKey &key)
{
return this->pop__impl(key, m_hash(key));
}
/**
* This method can be used to implement more complex custom behavior without having to do
* multiple lookups
*
* When the key did not yet exist in the map, the create_value function is called. Otherwise the
* modify_value function is called.
*
* Both functions are expected to take a single parameter of type `Value *`. In create_value,
* this pointer will point to uninitialized memory that has to be initialized by the function. In
* modify_value, it will point to an already initialized value.
*
* The function returns whatever is returned from the create_value or modify_value callback.
* Therefore, both callbacks have to have the same return type.
*
* In this example an integer is stored for every key. The initial value is five and we want to
* increase it every time the same key is used.
* map.add_or_modify(key,
* [](int *value) { *value = 5; },
* [](int *value) { (*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);
}
/**
* Same as `add_or_modify`, but accepts other key types that are supported by the hash function.
*/
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<Key>(key), create_value, modify_value, m_hash(key));
}
/**
* Returns a pointer to the value that corresponds to the given key. If the key is not in the
* map, nullptr is returned.
*
* This is similar to std::unordered_map::find.
*/
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);
}
/**
* Same as `lookup_ptr`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey> const Value *lookup_ptr_as(const ForwardKey &key) const
{
return this->lookup_ptr__impl(key, m_hash(key));
}
template<typename ForwardKey> Value *lookup_ptr_as(const ForwardKey &key)
{
return const_cast<Value *>(this->lookup_ptr__impl(key, m_hash(key)));
}
/**
* Returns a reference to the value that corresponds to the given key. This invokes undefined
* behavior when the key is not in the map.
*/
const Value &lookup(const Key &key) const
{
return this->lookup_as(key);
}
Value &lookup(const Key &key)
{
return this->lookup_as(key);
}
/**
* Same as `lookup`, but accepts other key types that are supported by the hash function.
*/
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;
}
/**
* Returns a copy of the value that corresponds to the given key. If the key is not in the
* map, the provided default_value is returned.
*/
Value lookup_default(const Key &key, const Value &default_value) const
{
return this->lookup_default_as(key, default_value);
}
/**
* Same as `lookup_default`, but accepts other key types that are supported by the hash function.
*/
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);
}
}
/**
* Returns a reference to the value that corresponds to the given key. If the key is not yet in
* the map, it will be newly added.
*
* The create_value callback is only called when the key did not exist yet. It is expected to
* take no parameters and return the value to be inserted.
*/
template<typename CreateValueF>
Value &lookup_or_add(const Key &key, const CreateValueF &create_value)
{
return this->lookup_or_add_as(key, create_value);
}
template<typename CreateValueF> Value &lookup_or_add(Key &&key, const CreateValueF &create_value)
{
return this->lookup_or_add_as(std::move(key), create_value);
}
/**
* Same as `lookup_or_add`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey, typename CreateValueF>
Value &lookup_or_add_as(ForwardKey &&key, const CreateValueF &create_value)
{
return this->lookup_or_add__impl(std::forward<ForwardKey>(key), create_value, m_hash(key));
}
/**
* Returns a reference to the value that corresponds to the given key. If the key is not yet in
* the map, it will be newly added. The newly added value will be default constructed.
*/
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));
}
/**
* Same as `lookup_or_add_default`, but accepts other key types that are supported by the hash
* function.
*/
template<typename ForwardKey> Value &lookup_or_add_default_as(ForwardKey &&key)
{
return this->lookup_or_add(std::forward<ForwardKey>(key), []() { return Value(); });
}
/**
* Calls the provided callback for every key-value-pair in the map. The callback is expected
* to take a `const Key &` as first and a `const Value &` as second parameter.
*/
template<typename FuncT> void foreach_item(const FuncT &func) const
{
uint32_t size = this->size();
for (uint32_t i = 0; i < size; i++) {
const Slot &slot = m_slots[i];
if (slot.is_occupied()) {
const Key &key = *slot.key();
const Value &value = *slot.value();
func(key, value);
}
}
}
/**
* A utility iterator that reduces the amount of code when implementing the actual iterators.
* This uses the "curiously recurring template pattern" (CRTP).
*/
template<typename SubIterator> struct BaseIterator {
Slot *m_slots;
uint32_t m_total_slots;
uint32_t m_current_slot;
BaseIterator(const Slot *slots, uint32_t total_slots, uint32_t current_slot)
: m_slots(const_cast<Slot *>(slots)),
m_total_slots(total_slots),
m_current_slot(current_slot)
{
}
BaseIterator &operator++()
{
while (++m_current_slot < m_total_slots) {
if (m_slots[m_current_slot].is_occupied()) {
break;
}
}
return *this;
}
friend bool operator!=(const BaseIterator &a, const BaseIterator &b)
{
BLI_assert(a.m_slots == b.m_slots);
BLI_assert(a.m_total_slots == b.m_total_slots);
return a.m_current_slot != b.m_current_slot;
}
SubIterator begin() const
{
for (uint32_t i = 0; i < m_total_slots; i++) {
if (m_slots[i].is_occupied()) {
return SubIterator(m_slots, m_total_slots, i);
}
}
return this->end();
}
SubIterator end() const
{
return SubIterator(m_slots, m_total_slots, m_total_slots);
}
Slot ¤t_slot() const
{
return m_slots[m_current_slot];
}
};
class KeyIterator final : public BaseIterator<KeyIterator> {
public:
KeyIterator(const Slot *slots, uint32_t total_slots, uint32_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:
ValueIterator(const Slot *slots, uint32_t total_slots, uint32_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:
MutableValueIterator(const Slot *slots, uint32_t total_slots, uint32_t current_slot)
: BaseIterator<MutableValueIterator>(slots, total_slots, current_slot)
{
}
Value &operator*()
{
return *this->current_slot().value();
}
};
class ItemIterator final : public BaseIterator<ItemIterator> {
public:
ItemIterator(const Slot *slots, uint32_t total_slots, uint32_t current_slot)
: BaseIterator<ItemIterator>(slots, total_slots, current_slot)
{
}
struct Item {
const Key &key;
const Value &value;
};
Item operator*() const
{
const Slot &slot = this->current_slot();
return {*slot.key(), *slot.value()};
}
};
class MutableItemIterator final : public BaseIterator<MutableItemIterator> {
public:
MutableItemIterator(const Slot *slots, uint32_t total_slots, uint32_t current_slot)
: BaseIterator<MutableItemIterator>(slots, total_slots, current_slot)
{
}
struct Item {
const Key &key;
Value &value;
};
Item operator*() const
{
Slot &slot = this->current_slot();
return {*slot.key(), *slot.value()};
}
};
/**
* Allows writing a range-for loop that iterates over all keys. The iterator is invalidated, when
* the map is changed.
*/
KeyIterator keys() const
{
return KeyIterator(m_slots.data(), m_slots.size(), 0);
}
/**
* Returns an iterator over all values in the map. The iterator is invalidated, when the map is
* changed.
*/
ValueIterator values() const
{
return ValueIterator(m_slots.data(), m_slots.size(), 0);
}
/**
* Returns an iterator over all values in the map and allows you to change the values. The
* iterator is invalidated, when the map is changed.
*/
MutableValueIterator values()
{
return MutableValueIterator(m_slots.data(), m_slots.size(), 0);
}
/**
* Returns an iterator over all key-value-pairs in the map. The key-value-pairs are stored in
* a temporary struct with a .key and a .value field.The iterator is invalidated, when the map is
* changed.
*/
ItemIterator items() const
{
return ItemIterator(m_slots.data(), m_slots.size(), 0);
}
/**
* Returns an iterator over all key-value-pairs in the map. The key-value-pairs are stored in
* a temporary struct with a .key and a .value field. The iterator is invalidated, when the map
* is changed.
*
* This iterator also allows you to modify the value (but not the key).
*/
MutableItemIterator items()
{
return MutableItemIterator(m_slots.data(), m_slots.size(), 0);
}
/**
* Print common statistics like size and collision count. This is useful for debugging purposes.
*/
void print_stats(StringRef name = "") const
{
HashTableStats stats(*this, this->keys());
stats.print();
}
/**
* Return the number of key-value-pairs that are stored in the map.
*/
uint32_t size() const
{
return m_occupied_and_removed_slots - m_removed_slots;
}
/**
* Returns true if there are no elements in the map.
*
* This is similar to std::unordered_map::empty.
*/
bool is_empty() const
{
return m_occupied_and_removed_slots == m_removed_slots;
}
/**
* Returns the number of available slots. This is mostly for debugging purposes.
*/
uint32_t capacity() const
{
return m_slots.size();
}
/**
* Returns the amount of removed slots in the set. This is mostly for debugging purposes.
*/
uint32_t removed_amount() const
{
return m_removed_slots;
}
/**
* Returns the bytes required per element. This is mostly for debugging purposes.
*/
uint32_t size_per_element() const
{
return sizeof(Slot);
}
/**
* Returns the approximate memory requirements of the map in bytes. This becomes more exact the
* larger the map becomes.
*/
uint32_t size_in_bytes() const
{
return sizeof(Slot) * m_slots.size();
}
/**
* Potentially resize the map such that the specified number of elements can be added without
* another grow operation.
*/
void reserve(uint32_t n)
{
if (m_usable_slots < n) {
this->realloc_and_reinsert(n);
}
}
/**
* Removes all key-value-pairs from the map.
*/
void clear()
{
this->~Map();
new (this) Map();
}
/**
* Get the number of collisions that the probing strategy has to go through to find the key or
* determine that it is not in the map.
*/
uint32_t count_collisions(const Key &key) const
{
return this->count_collisions__impl(key, m_hash(key));
}
private:
BLI_NOINLINE void realloc_and_reinsert(uint32_t min_usable_slots)
{
uint32_t total_slots, usable_slots;
m_max_load_factor.compute_total_and_usable_slots(
SlotArray::inline_buffer_capacity(), min_usable_slots, &total_slots, &usable_slots);
uint32_t new_slot_mask = total_slots - 1;
/**
* Optimize the case when the map was empty beforehand. We can avoid some copies here.
*/
if (this->size() == 0) {
m_slots.~Array();
new (&m_slots) SlotArray(total_slots);
m_removed_slots = 0;
m_occupied_and_removed_slots = 0;
m_usable_slots = usable_slots;
m_slot_mask = new_slot_mask;
return;
}
SlotArray new_slots(total_slots);
for (Slot &slot : m_slots) {
if (slot.is_occupied()) {
this->add_after_grow_and_destruct_old(slot, new_slots, new_slot_mask);
}
}
/* All occupied slots have been destructed already and empty/removed slots are assumed to be
* trivially destructible. */
m_slots.clear_without_destruct();
m_slots = std::move(new_slots);
m_occupied_and_removed_slots -= m_removed_slots;
m_usable_slots = usable_slots;
m_removed_slots = 0;
m_slot_mask = new_slot_mask;
}
void add_after_grow_and_destruct_old(Slot &old_slot,
SlotArray &new_slots,
uint32_t new_slot_mask)
{
uint32_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.relocate_occupied_here(old_slot, hash);
return;
}
}
SLOT_PROBING_END();
}
template<typename ForwardKey> bool contains__impl(const ForwardKey &key, uint32_t hash) const
{
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.is_empty()) {
return false;
}
if (slot.contains(key, m_is_equal, hash)) {
return true;
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey, typename ForwardValue>
void add_new__impl(ForwardKey &&key, ForwardValue &&value, uint32_t hash)
{
BLI_assert(!this->contains_as(key));
this->ensure_can_add();
m_occupied_and_removed_slots++;
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.is_empty()) {
slot.occupy(std::forward<ForwardKey>(key), std::forward<ForwardValue>(value), hash);
return;
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey, typename ForwardValue>
bool add__impl(ForwardKey &&key, ForwardValue &&value, uint32_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);
m_occupied_and_removed_slots++;
return true;
}
if (slot.contains(key, m_is_equal, hash)) {
return false;
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey> bool remove__impl(const ForwardKey &key, uint32_t hash)
{
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.contains(key, m_is_equal, hash)) {
slot.remove();
m_removed_slots++;
return true;
}
if (slot.is_empty()) {
return false;
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey> void remove_contained__impl(const ForwardKey &key, uint32_t hash)
{
BLI_assert(this->contains_as(key));
m_removed_slots++;
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.contains(key, m_is_equal, hash)) {
slot.remove();
return;
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey> Value pop__impl(const ForwardKey &key, uint32_t hash)
{
BLI_assert(this->contains_as(key));
m_removed_slots++;
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.contains(key, m_is_equal, hash)) {
Value value = *slot.value();
slot.remove();
return value;
}
}
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,
uint32_t hash) -> decltype(create_value(nullptr))
{
using CreateReturnT = decltype(create_value(nullptr));
using ModifyReturnT = decltype(modify_value(nullptr));
BLI_STATIC_ASSERT((std::is_same<CreateReturnT, ModifyReturnT>::value),
"Both callbacks should return the same type.");
this->ensure_can_add();
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.is_empty()) {
m_occupied_and_removed_slots++;
slot.occupy_without_value(std::forward<ForwardKey>(key), hash);
Value *value_ptr = slot.value();
return create_value(value_ptr);
}
if (slot.contains(key, m_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__impl(ForwardKey &&key, const CreateValueF &create_value, uint32_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);
m_occupied_and_removed_slots++;
return *slot.value();
}
if (slot.contains(key, m_is_equal, hash)) {
return *slot.value();
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey, typename ForwardValue>
bool add_overwrite__impl(ForwardKey &&key, ForwardValue &&value, uint32_t hash)
{
auto create_func = [&](Value *ptr) {
new (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 Value *lookup_ptr__impl(const ForwardKey &key, uint32_t hash) const
{
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.is_empty()) {
return nullptr;
}
if (slot.contains(key, m_is_equal, hash)) {
return slot.value();
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey>
uint32_t count_collisions__impl(const ForwardKey &key, uint32_t hash) const
{
uint32_t collisions = 0;
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.contains(key, m_is_equal, hash)) {
return collisions;
}
if (slot.is_empty()) {
return collisions;
}
collisions++;
}
MAP_SLOT_PROBING_END();
}
void ensure_can_add()
{
if (m_occupied_and_removed_slots >= m_usable_slots) {
this->realloc_and_reinsert(this->size() + 1);
BLI_assert(m_occupied_and_removed_slots < m_usable_slots);
}
}
};
/**
* A wrapper for std::unordered_map with the API of blender::Map. This can be used for
* benchmarking.
*/
template<typename Key, typename Value> class StdUnorderedMapWrapper {
private:
using MapType = std::unordered_map<Key, Value, blender::DefaultHash<Key>>;
MapType m_map;
public:
uint32_t size() const
{
return (uint32_t)m_map.size();
}
bool is_empty() const
{
return m_map.empty();
}
void reserve(uint32_t n)
{
m_map.reserve(n);
}
template<typename ForwardKey, typename ForwardValue>
void add_new(ForwardKey &&key, ForwardValue &&value)
{
m_map.insert({std::forward<ForwardKey>(key), std::forward<ForwardValue>(value)});
}
template<typename ForwardKey, typename ForwardValue>
bool add(ForwardKey &&key, ForwardValue &&value)
{
return m_map.insert({std::forward<ForwardKey>(key), std::forward<ForwardValue>(value)}).second;
}
bool contains(const Key &key) const
{
return m_map.find(key) != m_map.end();
}
bool remove(const Key &key)
{
return (bool)m_map.erase(key);
}
Value &lookup(const Key &key)
{
return m_map.find(key)->second;
}
const Value &lookup(const Key &key) const
{
return m_map.find(key)->second;
}
void clear()
{
m_map.clear();
}
void print_stats(StringRef UNUSED(name) = "") const
{
}
};
} // namespace blender
#endif /* __BLI_MAP_HH__ */
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