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/* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
/** \file
* \ingroup bli
*
* A `blender::MultiValueMap<Key, Value>` is an unordered associative container that stores
* key-value pairs. It is different from `blender::Map` in that it can store multiple values for
* the same key. The list of values that corresponds to a specific key can contain duplicates
* and their order is maintained.
*
* This data structure is different from a `std::multi_map`, because multi_map can store the same
* key more than once and MultiValueMap can't.
*
* Currently, this class exists mainly for convenience. There are no performance benefits over
* using Map<Key, Vector<Value>>. In the future, a better implementation for this data structure
* can be developed.
*/
#include "BLI_map.hh"
#include "BLI_vector.hh"
namespace blender {
template<typename Key, typename Value> class MultiValueMap {
public:
using size_type = int64_t;
private:
using MapType = Map<Key, Vector<Value>>;
MapType map_;
public:
/**
* Add a new value for the given key. If the map contains the key already, the value will be
* appended to the list of corresponding values.
*/
void add(const Key &key, const Value &value)
{
this->add_as(key, value);
}
void add(const Key &key, Value &&value)
{
this->add_as(key, std::move(value));
}
void add(Key &&key, const Value &value)
{
this->add_as(std::move(key), value);
}
void add(Key &&key, Value &&value)
{
this->add_as(std::move(key), std::move(value));
}
template<typename ForwardKey, typename ForwardValue>
void add_as(ForwardKey &&key, ForwardValue &&value)
{
Vector<Value> &vector = map_.lookup_or_add_default_as(std::forward<ForwardKey>(key));
vector.append(std::forward<ForwardValue>(value));
}
void add_non_duplicates(const Key &key, const Value &value)
{
Vector<Value> &vector = map_.lookup_or_add_default_as(key);
vector.append_non_duplicates(value);
}
/**
* Add all given values to the key.
*/
void add_multiple(const Key &key, Span<Value> values)
{
this->add_multiple_as(key, values);
}
void add_multiple(Key &&key, Span<Value> values)
{
this->add_multiple_as(std::move(key), values);
}
template<typename ForwardKey> void add_multiple_as(ForwardKey &&key, Span<Value> values)
{
Vector<Value> &vector = map_.lookup_or_add_default_as(std::forward<ForwardKey>(key));
vector.extend(values);
}
/**
* Get a span to all the values that are stored for the given key.
*/
Span<Value> lookup(const Key &key) const
{
return this->lookup_as(key);
}
template<typename ForwardKey> Span<Value> lookup_as(const ForwardKey &key) const
{
const Vector<Value> *vector = map_.lookup_ptr_as(key);
if (vector != nullptr) {
return vector->as_span();
}
return {};
}
/**
* Get a mutable span to all the values that are stored for the given key.
*/
MutableSpan<Value> lookup(const Key &key)
{
return this->lookup_as(key);
}
template<typename ForwardKey> MutableSpan<Value> lookup_as(const ForwardKey &key)
{
Vector<Value> *vector = map_.lookup_ptr_as(key);
if (vector != nullptr) {
return vector->as_mutable_span();
}
return {};
}
/**
* NOTE: This signature will change when the implementation changes.
*/
typename MapType::ItemIterator items() const
{
return map_.items();
}
/**
* NOTE: This signature will change when the implementation changes.
*/
typename MapType::KeyIterator keys() const
{
return map_.keys();
}
/**
* NOTE: This signature will change when the implementation changes.
*/
typename MapType::ValueIterator values() const
{
return map_.values();
}
void clear()
{
map_.clear();
}
};
} // namespace blender
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