libcruft-util/hash/murmur/murmur1.hpp
Danny Robson f6056153e3 rename root namespace from util to cruft
This places, at long last, the core library code into the same namespace
as the extended library code.
2018-08-05 14:42:02 +10:00

47 lines
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C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2015 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_HASH_MURMUR_MURMUR1_HPP
#define __UTIL_HASH_MURMUR_MURMUR1_HPP
#include "../../view.hpp"
#include <cstdint>
#include <cstddef>
// Austin Appleby's MumurHash1
namespace cruft::hash {
class murmur1 {
public:
using digest_t = uint32_t;
using seed_t = uint32_t;
murmur1 (seed_t _seed):
m_seed (_seed)
{ ; }
static constexpr uint32_t mix (uint32_t h, uint32_t k)
{
constexpr uint32_t m = 0xc6a4a793;
h += k;
h *= m;
h ^= h >> 16;
return h;
}
digest_t operator() (cruft::view<const uint8_t*> data) const noexcept;
private:
seed_t m_seed;
};
}
#endif