libcruft-util/hash/fletcher.hpp

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/*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
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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
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2010-2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_HASH_FLETCHER_HPP
#define __UTIL_HASH_FLETCHER_HPP
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#include "../types/bits.hpp"
#include "../view.hpp"
#include <cstdint>
#include <cstdlib>
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///////////////////////////////////////////////////////////////////////////////
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namespace util::hash {
template <typename DigestT>
class fletcher {
public:
using digest_t = DigestT;
using part_t = typename bytes_type<sizeof (digest_t) / 2>::uint;
fletcher (part_t modulus, part_t a, part_t b);
digest_t
operator() (util::view<const std::uint8_t*>) const noexcept;
private:
struct state_t {
part_t a, b;
};
const digest_t m_modulus;
const state_t m_initial;
};
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}
#endif