77 lines
1.8 KiB
C++
77 lines
1.8 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2024
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include <cstdint>
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#include <functional>
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namespace td {
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template <class KeyT>
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bool is_hash_table_key_empty(const KeyT &key) {
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return key == KeyT();
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}
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inline uint32 randomize_hash(uint32 h) {
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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template <class Type>
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struct Hash {
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uint32 operator()(const Type &value) const;
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};
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template <class Type>
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struct Hash<Type *> {
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uint32 operator()(Type *pointer) const {
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return Hash<uint64>()(reinterpret_cast<std::uintptr_t>(pointer));
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}
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};
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template <>
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inline uint32 Hash<char>::operator()(const char &value) const {
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return randomize_hash(static_cast<uint32>(value));
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}
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template <>
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inline uint32 Hash<int32>::operator()(const int32 &value) const {
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return randomize_hash(static_cast<uint32>(value));
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}
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template <>
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inline uint32 Hash<uint32>::operator()(const uint32 &value) const {
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return randomize_hash(value);
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}
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template <>
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inline uint32 Hash<int64>::operator()(const int64 &value) const {
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return randomize_hash(static_cast<uint32>(value + (value >> 32)));
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}
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template <>
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inline uint32 Hash<uint64>::operator()(const uint64 &value) const {
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return randomize_hash(static_cast<uint32>(value + (value >> 32)));
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}
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template <>
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inline uint32 Hash<string>::operator()(const string &value) const {
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return static_cast<uint32>(std::hash<string>()(value));
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}
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inline uint32 combine_hashes(uint32 first_hash, uint32 second_hash) {
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return first_hash * 2023654985u + second_hash;
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}
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} // namespace td
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