52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include "../../view.hpp"
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#include <array>
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#include <cstddef>
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#include <cstdint>
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// Austin Appleby's MurmurHash3
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namespace cruft::hash {
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namespace detail::murmur3 {
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template <size_t DigestBits, size_t ArchBits>
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struct digest_type { };
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template <> struct digest_type< 32,32> { using type = uint32_t; };
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template <> struct digest_type<128,32> { using type = std::array<uint32_t,4>; };
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template <> struct digest_type<128,64> { using type = std::array<uint64_t,2>; };
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};
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template <size_t DigestBits, size_t ArchBits>
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class murmur3 {
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public:
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murmur3 (uint32_t _seed):
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m_seed (_seed)
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{ ; }
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static_assert (DigestBits % 8 == 0);
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using digest_t = typename detail::murmur3::digest_type<DigestBits,ArchBits>::type;
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static uint32_t mix (uint32_t);
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static uint64_t mix (uint64_t);
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digest_t
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operator() (cruft::view<const uint8_t*> data) const noexcept;
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private:
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uint32_t m_seed;
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};
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using murmur3_32 = murmur3< 32,32>;
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using murmur3_128_x86 = murmur3<128,32>;
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using murmur3_128_x64 = murmur3<128,64>;
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} |