54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
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/*
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* This file is part of libgim.
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*
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* Waif is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* Waif is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2010 Danny Robson <danny@blubinc.net>
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*/
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#include "hash.hpp"
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// Thomas Wang's 32 bit mixing function
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uint32_t
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hash (uint32_t key) {
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uint32_t c2 = 0x27d4eb2d; // a prime or an odd constant
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key = (key ^ 61) ^ (key >> 16);
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key = key + (key << 3);
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key = key ^ (key >> 4);
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key = key * c2;
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key = key ^ (key >> 15);
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return key;
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}
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// Thomas Wang's 64 bit mixing function
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uint64_t
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hash (uint64_t key) {
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key = (~key) + (key << 21); // key = (key << 21) - key - 1;
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key = key ^ (key >> 24);
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key = (key + (key << 3)) + (key << 8); // key * 265
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key = key ^ (key >> 14);
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key = (key + (key << 2)) + (key << 4); // key * 21
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key = key ^ (key >> 28);
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key = key + (key << 31);
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return key;
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}
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uintptr_t
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hash (void *const key)
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{ return hash ((uintptr_t)key); }
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