rspamd/src/libutil/cxx/hash_util.hxx

/*
 * Copyright 2023 Vsevolod Stakhov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef RSPAMD_HASH_UTIL_HXX
#define RSPAMD_HASH_UTIL_HXX

#pragma once

#include <string_view>
#include <string>
#include "contrib/ankerl/unordered_dense.h"


namespace rspamd {
/*
 * Transparent smart pointers hashing
 */
template<typename T>
struct smart_ptr_equal {
	using is_transparent = void; /* We want to find values in a set of shared_ptr by reference */
	auto operator()(const std::shared_ptr<T> &a, const std::shared_ptr<T> &b) const
	{
		return (*a) == (*b);
	}
	auto operator()(const std::shared_ptr<T> &a, const T &b) const
	{
		return (*a) == b;
	}
	auto operator()(const T &a, const std::shared_ptr<T> &b) const
	{
		return a == (*b);
	}
	auto operator()(const std::unique_ptr<T> &a, const std::unique_ptr<T> &b) const
	{
		return (*a) == (*b);
	}
	auto operator()(const std::unique_ptr<T> &a, const T &b) const
	{
		return (*a) == b;
	}
	auto operator()(const T &a, const std::unique_ptr<T> &b) const
	{
		return a == (*b);
	}
};

template<typename T>
struct smart_ptr_hash {
	using is_transparent = void; /* We want to find values in a set of shared_ptr by reference */
	using is_avalanching = void;
	auto operator()(const std::shared_ptr<T> &a) const
	{
		return std::hash<T>()(*a);
	}
	auto operator()(const std::unique_ptr<T> &a) const
	{
		return std::hash<T>()(*a);
	}
	auto operator()(const T &a) const
	{
		return std::hash<T>()(a);
	}
};

/* Enable lookup by string view */
struct smart_str_equal {
	using is_transparent = void;
	auto operator()(const std::string &a, const std::string &b) const
	{
		return a == b;
	}
	auto operator()(const std::string_view &a, const std::string &b) const
	{
		return a == b;
	}
	auto operator()(const std::string &a, const std::string_view &b) const
	{
		return a == b;
	}
};

struct smart_str_hash {
	using is_transparent = void;
	using is_avalanching = void;
	auto operator()(const std::string &a) const
	{
		return ankerl::unordered_dense::hash<std::string>()(a);
	}
	auto operator()(const std::string_view &a) const
	{
		return ankerl::unordered_dense::hash<std::string_view>()(a);
	}
};

}// namespace rspamd

#endif//RSPAMD_HASH_UTIL_HXX