90 lines
2.3 KiB
C++
90 lines
2.3 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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#include "./fletcher.hpp"
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#include "../debug.hpp"
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using util::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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m_state { m_initial }
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{ ; }
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//-----------------------------------------------------------------------------
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template <typename T>
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void
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fletcher<T>::reset (void)
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{
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m_state = m_initial;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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void
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fletcher<T>::update (const void *restrict data, size_t size) noexcept
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{
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CHECK (data);
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auto first = static_cast<const uint8_t *restrict> (data);
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update (first, first + size);
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}
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//-----------------------------------------------------------------------------
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template <typename T>
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void
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fletcher<T>::update (const uint8_t *restrict first, const uint8_t *restrict last) noexcept
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{
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CHECK (first);
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CHECK (last);
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CHECK_LE (first, last);
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for (auto cursor = first; cursor < last; ++cursor) {
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m_state.a = (m_state.a + *cursor ) % m_modulus;
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m_state.b = (m_state.a + m_state.b) % m_modulus;
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}
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}
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//-----------------------------------------------------------------------------
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template <typename T>
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void
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fletcher<T>::finish (void)
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{ ; }
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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typename fletcher<T>::digest_t
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fletcher<T>::digest (void) const
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{
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return (m_state.b << (sizeof (part_t) * 8)) + m_state.a;
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}
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///////////////////////////////////////////////////////////////////////////////
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template class util::hash::fletcher<uint32_t>;
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