Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : #ifndef LIBMESH_HASHING_H
      19             : #define LIBMESH_HASHING_H
      20             : 
      21             : #include <functional>
      22             : 
      23             : namespace libMesh
      24             : {
      25             : namespace boostcopy
      26             : {
      27             : 
      28    12107909 : inline void hash_combine_impl(std::size_t & seed, std::size_t value)
      29             : {
      30   116449068 :   seed ^= value + 0x9e3779b9 + (seed<<6) + (seed>>2);
      31    12107909 : }
      32             : 
      33             : template <typename T>
      34    12107907 : inline void hash_combine(std::size_t & seed, const T & value)
      35             : {
      36             :   using std::hash;
      37   113619484 :   hash_combine_impl(seed, hash<T>{}(value));
      38    12107907 : }
      39             : 
      40             : }
      41             : 
      42             : 
      43             : // Fix for STL laziness
      44             : struct hash {
      45             : public:
      46             :   template <typename T1, typename T2>
      47    11971590 :   std::size_t operator()(const std::pair<T1, T2> & x) const
      48             :   {
      49             :     // Hopefully argument-based lookup lets us recurse with this
      50             :     using std::hash;
      51             : 
      52   120262080 :     std::size_t returnval = hash<T1>()(x.first);
      53    18838559 :     boostcopy::hash_combine(returnval, x.second);
      54             : 
      55    11971590 :     return returnval;
      56             :   }
      57             : 
      58             :   template <typename T, std::size_t N>
      59       32260 :   std::size_t operator()(const std::array<T, N> & x) const
      60             :   {
      61             :     // Hopefully argument-based lookup lets us recurse with this
      62             :     using std::hash;
      63             : 
      64        2908 :     std::size_t returnval = 0;
      65      140672 :     for (std::size_t i = 0; i != N; ++i)
      66       17448 :       boostcopy::hash_combine(returnval, x[i]);
      67             : 
      68       32260 :     return returnval;
      69             :   }
      70             : };
      71             : 
      72             : 
      73             : }
      74             : 
      75             : #endif // LIBMESH_HASHING_H