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/* This file is part of KDevelop
Copyright 2012 Olivier de Gaalon <olivier.jg@gmail.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License version 2 as published by the Free Software Foundation.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifndef KDEVPLATFORM_KDEVHASH_H
#define KDEVPLATFORM_KDEVHASH_H
#include <QHash>
/**
* A helper class to implement hashing for aggregate types.
*
* @code
* class MyType {
* ...
* uint hash() const
* {
* KDevHash hash;
* return hash << m_1 << m_2 << ...;
* }
* };
* @endcode
*/
class KDevHash
{
public:
enum {
DEFAULT_SEED = 2166136261u
};
explicit KDevHash(uint hash = DEFAULT_SEED)
: m_hash(hash)
{}
KDevHash(const KDevHash&) = delete;
KDevHash& operator=(const KDevHash&) = delete;
inline operator uint() const
{
return m_hash;
}
template <typename T>
inline KDevHash& operator<<(T value)
{
m_hash = hash_combine(m_hash, qHash(value));
return *this;
}
static inline uint hash_combine(uint seed, uint hash)
{
// this is copied from boost::hash_combine
return seed ^ (hash + 0x9e3779b9 + (seed << 6) + (seed >> 2));
}
private:
uint m_hash;
};
#endif //KDEVPLATFORM_KDEVHASH_H
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