kicad/include/hash_eda.h

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2017 CERN
* Copyright (C) 2020 KiCad Developers, see AUTHORS.txt for contributors.
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* @author Maciej Suminski <maciej.suminski@cern.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#ifndef HASH_EDA_H_
#define HASH_EDA_H_
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/**
* @brief Hashing functions for EDA_ITEMs.
*/
#include <cstdlib>
#include <functional>
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class EDA_ITEM;
///> Enables/disables properties that will be used for calculating the hash.
///> The properties might be combined using the bitwise 'or' operator.
enum HASH_FLAGS
{
HASH_POS = 0x01,
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///> use coordinates relative to the parent object
REL_COORD = 0x02,
HASH_ROT = 0x04,
HASH_LAYER = 0x08,
HASH_NET = 0x10,
HASH_REF = 0x20,
HASH_VALUE = 0x40,
HASH_ALL = 0xff
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};
/**
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* Calculates hash of an EDA_ITEM.
* @param aItem is the item for which the hash will be computed.
* @return Hash value.
*/
std::size_t hash_eda( const EDA_ITEM* aItem, int aFlags = HASH_FLAGS::HASH_ALL );
/**
* This is a dummy function to take the final case of hash_combine below
* @param seed
*/
static inline void hash_combine( std::size_t &seed ) {}
/**
* @brief Combine multiple hashes utilizing previous hash result
* @tparam T A hashable type
* @param seed A seed value input and output for the result.
* @param val A hashable object of type T
*/
template< typename T, typename ... Types >
static inline void hash_combine( std::size_t &seed, const T &val, const Types &... args )
{
seed ^= std::hash<T>()( val ) + 0x9e3779b9 + ( seed << 6 ) + ( seed >> 2 );
hash_combine( seed, args... );
}
template <typename... Types>
static inline std::size_t hash_val( const Types &... args )
{
std::size_t seed = 0xa82de1c0;
hash_combine( seed, args... );
return seed;
}
#endif