ClickHouse/base/poco/Foundation/include/Poco/Dynamic/VarIterator.h

153 lines
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C++

//
// VarIterator.h
//
// Library: Foundation
// Package: Dynamic
// Module: VarIterator
//
// Definition of the VarIterator class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_VarIterator_INCLUDED
#define Foundation_VarIterator_INCLUDED
#include <algorithm>
#include <iterator>
#include "Poco/Exception.h"
namespace Poco
{
namespace Dynamic
{
class Var;
class Foundation_API VarIterator
/// VarIterator class.
{
public:
typedef std::bidirectional_iterator_tag iterator_category;
typedef Var value_type;
typedef std::ptrdiff_t difference_type;
typedef Var * pointer;
typedef Var & reference;
static const std::size_t POSITION_END;
/// End position indicator.
VarIterator(Var * pVar, bool positionEnd);
/// Creates the VarIterator and positions it at the end of
/// the recordset if positionEnd is true. Otherwise, it is
/// positioned at the beginning.
VarIterator(const VarIterator & other);
/// Creates a copy of other VarIterator.
~VarIterator();
/// Destroys the VarIterator.
VarIterator & operator=(const VarIterator & other);
/// Assigns the other VarIterator.
bool operator==(const VarIterator & other) const;
/// Equality operator.
bool operator!=(const VarIterator & other) const;
/// Inequality operator.
Var & operator*() const;
/// Returns value at the current position.
Var * operator->() const;
/// Returns pointer to the value at current position.
const VarIterator & operator++() const;
/// Advances by one position and returns current position.
VarIterator operator++(int) const;
/// Advances by one position and returns copy of the iterator with
/// previous current position.
const VarIterator & operator--() const;
/// Goes back by one position and returns copy of the iterator with
/// previous current position.
VarIterator operator--(int) const;
/// Goes back by one position and returns previous current position.
VarIterator operator+(std::size_t diff) const;
/// Returns a copy the VarIterator advanced by diff positions.
VarIterator operator-(std::size_t diff) const;
/// Returns a copy the VarIterator backed by diff positions.
/// Throws RangeException if diff is larger than current position.
void swap(VarIterator & other);
/// Swaps the VarIterator with another one.
private:
VarIterator();
void increment() const;
/// Increments the iterator position by one.
/// Throws RangeException if position is out of range.
void decrement() const;
/// Decrements the iterator position by one.
/// Throws RangeException if position is out of range.
void setPosition(std::size_t pos) const;
/// Sets the iterator position.
/// Throws RangeException if position is out of range.
Var * _pVar;
mutable std::size_t _position;
friend class Var;
};
///
/// inlines
///
inline bool VarIterator::operator==(const VarIterator & other) const
{
return _pVar == other._pVar && _position == other._position;
}
inline bool VarIterator::operator!=(const VarIterator & other) const
{
return _pVar != other._pVar || _position != other._position;
}
}
} // namespace Poco::Dynamic
namespace std
{
template <>
inline void swap<Poco::Dynamic::VarIterator>(Poco::Dynamic::VarIterator & s1, Poco::Dynamic::VarIterator & s2)
/// Full template specialization of std:::swap for VarIterator
{
s1.swap(s2);
}
}
#endif // Foundation_VarIterator_INCLUDED