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/****************************************************************************** |
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* Top contributors (to current version): |
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* Morgan Deters, Andres Noetzli, Mathias Preiner |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* [[ Add one-line brief description here ]] |
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* |
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* [[ Add lengthier description here ]] |
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* \todo document this file |
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*/ |
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#include "cvc5_public.h" |
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#ifndef CVC5__HASH_H |
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#define CVC5__HASH_H |
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#include <functional> |
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#include <string> |
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namespace std { |
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#ifdef CVC5_NEED_HASH_UINT64_T |
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// on some versions and architectures of GNU C++, we need a |
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// specialization of hash for 64-bit values |
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template <> |
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struct hash<uint64_t> { |
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size_t operator()(uint64_t v) const { |
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return v; |
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} |
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};/* struct hash<uint64_t> */ |
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#endif /* CVC5_NEED_HASH_UINT64_T */ |
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}/* std namespace */ |
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namespace cvc5 { |
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namespace fnv1a { |
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/** |
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* FNV-1a hash algorithm for 64-bit numbers. |
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* |
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* More details here: http://www.isthe.com/chongo/tech/comp/fnv/index.html |
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*/ |
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inline uint64_t fnv1a_64(uint64_t v, uint64_t hash = 14695981039346656037U) { |
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hash ^= v; |
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// Compute (hash * 1099511628211) |
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return hash + (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) + |
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(hash << 8) + (hash << 40); |
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} |
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} // namespace fnv1a |
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template <class T, class U, class HashT = std::hash<T>, class HashU = std::hash<U> > |
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struct PairHashFunction { |
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size_t operator()(const std::pair<T, U>& pr) const { |
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uint64_t hash = fnv1a::fnv1a_64(HashT()(pr.first)); |
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return static_cast<size_t>(fnv1a::fnv1a_64(HashU()(pr.second), hash)); |
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} |
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};/* struct PairHashFunction */ |
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} // namespace cvc5 |
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#endif /* CVC5__HASH_H */ |