61 lines
1.6 KiB
C++
61 lines
1.6 KiB
C++
/* SPDX-FileCopyrightText: 2024 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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/** \file
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* \ingroup bli
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*/
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#include <cstdint>
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#include <memory>
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#include "BLI_assert.h"
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namespace blender {
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/**
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* A #GenericKey allows different kinds of keys to be used in the same data-structure like a #Set
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* or #Map.
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*
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* Typically, the key is stored as `std::reference_wrapper<const GenericKey>` in the
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* data-structure. That implies that one has to make sure that the key is not destructed while it's
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* still in use.
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*/
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class GenericKey {
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public:
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virtual ~GenericKey() = default;
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/** The hash function has to be implemented by the non-abstract subclass. */
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virtual uint64_t hash() const = 0;
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/**
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* Check if the other key is equal to this one. Usually that involves a dynamic_cast to check if
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* it has the same type.
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*/
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virtual bool equal_to(const GenericKey &other) const = 0;
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/**
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* For efficiency, it can be good to not always allocate the key if it's just used for lookup.
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* This method allows the key to be converted into a heap-allocated version that can be stored
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* safely if necessary.
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*/
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virtual std::unique_ptr<GenericKey> to_storable() const = 0;
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friend bool operator==(const GenericKey &a, const GenericKey &b)
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{
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const bool are_equal = a.equal_to(b);
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/* Ensure that equality check is symmetric. */
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BLI_assert(are_equal == b.equal_to(a));
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return are_equal;
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}
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friend bool operator!=(const GenericKey &a, const GenericKey &b)
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{
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return !(a == b);
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}
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};
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} // namespace blender
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