libcruft-util/hash/xxhash.hpp

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2016-11-17 18:35:06 +11:00
/*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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 2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef CRUFT_UTIL_HASH_XXHASH_HPP
#define CRUFT_UTIL_HASH_XXHASH_HPP
#include <cstdint>
#include <type_traits>
namespace util::hash {
template <typename T>
class xxhash {
public:
static_assert (std::is_same<T,uint32_t>::value || std::is_same<T,uint64_t>::value);
using digest_t = T;
xxhash (void);
xxhash (uint32_t seed);
void update (const uint8_t *restrict first, const uint8_t *restrict last);
void finish (void);
digest_t digest (void) const;
void reset (void);
private:
uint32_t m_seed;
struct {
uint32_t total_len_32;
uint32_t large_len;
T v1, v2, v3, v4;
uint32_t mem32[4];
uint32_t memsize;
uint32_t reserved;
//uint64_t length;
//T v[4];
//T mem[4];
//unsigned memsize;
} m_state;
};
using xxhash32 = xxhash<uint32_t>;
using xxhash64 = xxhash<uint64_t>;
}
#endif