50 lines
1.7 KiB
C++
50 lines
1.7 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2010 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_HASH_HPP
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#define __UTIL_HASH_HPP
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#include <cstdint>
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#include <cstdlib>
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// All hashes are unsuitable for cryptographic operations nnless noted.
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namespace util {
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// Fast integer mixing operations by Thomas Wang.
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uint32_t wang32 (uint32_t key);
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uint64_t wang64 (uint64_t key);
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// Fast and general hashing using FNV-1a
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uint32_t fnv1a32 (const void *, size_t);
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uint64_t fnv1a64 (const void *, size_t);
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// General hashes for when you really just don't care about implementation
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inline uint32_t hash (uint32_t key) { return wang32 (key); }
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inline int32_t hash ( int32_t key) { return (int32_t) hash ((uint32_t)key); }
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inline uint64_t hash (uint64_t key) { return wang64 (key); }
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inline int64_t hash ( int64_t key) { return (int64_t) hash ((uint64_t)key); }
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inline uintptr_t hash (const void *key) {
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return sizeof (uintptr_t) == 32 ? wang32 (reinterpret_cast<uintptr_t> (key)) :
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wang64 (reinterpret_cast<uintptr_t> (key));
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}
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}
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#endif
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