ClickHouse/dbms/include/DB/Common/HashTable/HashMap.h

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#pragma once
#include <DB/Common/HashTable/Hash.h>
#include <DB/Common/HashTable/HashTable.h>
#include <DB/Common/HashTable/HashTableAllocator.h>
template <typename Key, typename TMapped, typename Hash, typename TState = HashTableNoState>
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struct HashMapCell
{
typedef TMapped Mapped;
typedef TState State;
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typedef std::pair<Key, Mapped> value_type;
value_type value;
HashMapCell() {}
HashMapCell(const Key & key_, const State & state) : value(key_, Mapped()) {}
HashMapCell(const value_type & value_, const State & state) : value(value_) {}
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value_type & getValue() { return value; }
const value_type & getValue() const { return value; }
static Key & getKey(value_type & value) { return value.first; }
static const Key & getKey(const value_type & value) { return value.first; }
bool keyEquals(const Key & key_) const { return value.first == key_; }
bool keyEquals(const HashMapCell & other) const { return value.first == other.value.first; }
void setHash(size_t hash_value) {}
size_t getHash(const Hash & hash) const { return hash(value.first); }
bool isZero(const State & state) const { return isZero(value.first, state); }
static bool isZero(const Key & key, const State & state) { return ZeroTraits::check(key); }
/// Установить значение ключа в ноль.
void setZero() { ZeroTraits::set(value.first); }
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/// Нужно ли хранить нулевой ключ отдельно (то есть, могут ли в хэш-таблицу вставить нулевой ключ).
static constexpr bool need_zero_value_storage = true;
/// Является ли ячейка удалённой.
bool isDeleted() const { return false; }
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void setMapped(const value_type & value_) { value.second = value_.second; }
/// Сериализация, в бинарном и текстовом виде.
void write(DB::WriteBuffer & wb) const
{
DB::writeBinary(value.first, wb);
DB::writeBinary(value.second, wb);
}
void writeText(DB::WriteBuffer & wb) const
{
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DB::writeDoubleQuoted(value.first, wb);
DB::writeChar(',', wb);
DB::writeDoubleQuoted(value.second, wb);
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}
/// Десериализация, в бинарном и текстовом виде.
void read(DB::ReadBuffer & rb)
{
DB::readBinary(value.first, rb);
DB::readBinary(value.second, rb);
}
void readText(DB::ReadBuffer & rb)
{
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DB::readDoubleQuoted(value.first, rb);
DB::assertString(",", rb);
DB::readDoubleQuoted(value.second, rb);
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}
};
template
<
typename Key,
typename Cell,
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typename Hash = DefaultHash<Key>,
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typename Grower = HashTableGrower<>,
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typename Allocator = HashTableAllocator
>
class HashMapTable : public HashTable<Key, Cell, Hash, Grower, Allocator>
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{
public:
typedef Key key_type;
typedef typename Cell::Mapped mapped_type;
typedef typename Cell::value_type value_type;
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mapped_type & operator[](Key x)
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{
typename HashMapTable::iterator it;
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bool inserted;
this->emplace(x, it, inserted);
if (inserted)
new(&it->second) mapped_type();
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return it->second;
}
};
template
<
typename Key,
typename Mapped,
typename Hash = DefaultHash<Key>,
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typename Grower = HashTableGrower<>,
typename Allocator = HashTableAllocator
>
using HashMap = HashMapTable<Key, HashMapCell<Key, Mapped, Hash>, Hash, Grower, Allocator>;