42 lines
1.1 KiB
C++
42 lines
1.1 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 2010 Danny Robson <danny@nerdcruft.net>
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*/
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#include "fletcher.hpp"
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using cruft::hash::fletcher;
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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fletcher<T>::fletcher (part_t _modulus, part_t _a, part_t _b):
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m_modulus { _modulus },
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m_initial { _a, _b }
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{ ; }
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///////////////////////////////////////////////////////////////////////////////
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template <typename DigestT>
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typename fletcher<DigestT>::digest_t
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fletcher<DigestT>::operator() (cruft::view<const std::uint8_t*> data) const noexcept
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{
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state_t accum = m_initial;
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for (const auto i: data) {
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accum.a = (accum.a + i) % m_modulus;
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accum.b = (accum.a + accum.b) % m_modulus;
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}
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return accum.b << (sizeof(part_t) * 8u) | accum.a;
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}
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///////////////////////////////////////////////////////////////////////////////
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template class cruft::hash::fletcher<uint32_t>;
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