ClickHouse/contrib/libpoco/Foundation/include/Poco/HashMap.h

231 lines
3.9 KiB
C++

//
// HashMap.h
//
// $Id: //poco/1.4/Foundation/include/Poco/HashMap.h#1 $
//
// Library: Foundation
// Package: Hashing
// Module: HashMap
//
// Definition of the HashMap class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_HashMap_INCLUDED
#define Foundation_HashMap_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/LinearHashTable.h"
#include "Poco/Exception.h"
#include <utility>
namespace Poco {
template <class Key, class Value>
struct HashMapEntry
/// This class template is used internally by HashMap.
{
Key first;
Value second;
HashMapEntry():
first(),
second()
{
}
HashMapEntry(const Key& key):
first(key),
second()
{
}
HashMapEntry(const Key& key, const Value& value):
first(key),
second(value)
{
}
bool operator == (const HashMapEntry& entry) const
{
return first == entry.first;
}
bool operator != (const HashMapEntry& entry) const
{
return first != entry.first;
}
};
template <class HME, class KeyHashFunc>
struct HashMapEntryHash
/// This class template is used internally by HashMap.
{
std::size_t operator () (const HME& entry) const
{
return _func(entry.first);
}
private:
KeyHashFunc _func;
};
template <class Key, class Mapped, class HashFunc = Hash<Key> >
class HashMap
/// This class implements a map using a LinearHashTable.
///
/// A HashMap can be used just like a std::map.
{
public:
typedef Key KeyType;
typedef Mapped MappedType;
typedef Mapped& Reference;
typedef const Mapped& ConstReference;
typedef Mapped* Pointer;
typedef const Mapped* ConstPointer;
typedef HashMapEntry<Key, Mapped> ValueType;
typedef std::pair<KeyType, MappedType> PairType;
typedef HashMapEntryHash<ValueType, HashFunc> HashType;
typedef LinearHashTable<ValueType, HashType> HashTable;
typedef typename HashTable::Iterator Iterator;
typedef typename HashTable::ConstIterator ConstIterator;
HashMap()
/// Creates an empty HashMap.
{
}
HashMap(std::size_t initialReserve):
_table(initialReserve)
/// Creates the HashMap with room for initialReserve entries.
{
}
HashMap& operator = (const HashMap& map)
/// Assigns another HashMap.
{
HashMap tmp(map);
swap(tmp);
return *this;
}
void swap(HashMap& map)
/// Swaps the HashMap with another one.
{
_table.swap(map._table);
}
ConstIterator begin() const
{
return _table.begin();
}
ConstIterator end() const
{
return _table.end();
}
Iterator begin()
{
return _table.begin();
}
Iterator end()
{
return _table.end();
}
ConstIterator find(const KeyType& key) const
{
ValueType value(key);
return _table.find(value);
}
Iterator find(const KeyType& key)
{
ValueType value(key);
return _table.find(value);
}
std::size_t count(const KeyType& key) const
{
ValueType value(key);
return _table.find(value) != _table.end() ? 1 : 0;
}
std::pair<Iterator, bool> insert(const PairType& pair)
{
ValueType value(pair.first, pair.second);
return _table.insert(value);
}
std::pair<Iterator, bool> insert(const ValueType& value)
{
return _table.insert(value);
}
void erase(Iterator it)
{
_table.erase(it);
}
void erase(const KeyType& key)
{
Iterator it = find(key);
_table.erase(it);
}
void clear()
{
_table.clear();
}
std::size_t size() const
{
return _table.size();
}
bool empty() const
{
return _table.empty();
}
ConstReference operator [] (const KeyType& key) const
{
ConstIterator it = _table.find(key);
if (it != _table.end())
return it->second;
else
throw NotFoundException();
}
Reference operator [] (const KeyType& key)
{
ValueType value(key);
std::pair<Iterator, bool> res = _table.insert(value);
return res.first->second;
}
private:
HashTable _table;
};
} // namespace Poco
#endif // Foundation_HashMap_INCLUDED