40 lines
1.0 KiB
C++
40 lines
1.0 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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#include "murmur1.hpp"
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#include "common.hpp"
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#include "../../endian.hpp"
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using cruft::hash::murmur1;
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///////////////////////////////////////////////////////////////////////////////
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uint32_t
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murmur1::operator() (cruft::view<const uint8_t*> data) const noexcept
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{
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static const uint32_t m = 0xc6a4a793;
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uint32_t h = m_seed ^ ((data.size () & 0xffffffff) * m);
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// mix the body
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auto cursor = data.begin ();
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for (auto last = data.end () - data.size () % sizeof (uint32_t); cursor < last; cursor += 4)
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h = mix (h, cruft::readhe<uint32_t> (cursor));
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// mix the tail
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if (data.size () % sizeof (uint32_t))
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h = mix (h, murmur::tail<uint32_t> (cursor, data.size ()));
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// finalise
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h *= m; h ^= h >> 10;
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h *= m; h ^= h >> 17;
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return h;
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}
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