83 lines
2.8 KiB
C++
83 lines
2.8 KiB
C++
// metrohash128.h
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//
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// Copyright 2015-2018 J. Andrew Rogers
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//
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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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#ifndef METROHASH_METROHASH_128_H
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#define METROHASH_METROHASH_128_H
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#include <stdint.h>
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#include <utility>
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typedef std::pair<uint64_t, uint64_t> _uint128_t;
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class MetroHash128
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{
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public:
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static const uint32_t bits = 128;
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// Constructor initializes the same as Initialize()
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MetroHash128(const uint64_t seed=0);
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// Initializes internal state for new hash with optional seed
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void Initialize(const uint64_t seed=0);
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// Update the hash state with a string of bytes. If the length
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// is sufficiently long, the implementation switches to a bulk
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// hashing algorithm directly on the argument buffer for speed.
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void Update(const void* buffer, const uint64_t length) {
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Update(reinterpret_cast<const uint8_t*>(buffer), length);
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}
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void Update(const uint8_t* buffer, const uint64_t length);
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template <class T>
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void Update(const T& x) {
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Update(&x, sizeof(x));
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}
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// Constructs the final hash and writes it to the argument buffer.
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// After a hash is finalized, this instance must be Initialized()-ed
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// again or the behavior of Update() and Finalize() is undefined.
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void Finalize(uint8_t * const hash);
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// A non-incremental function implementation. This can be significantly
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// faster than the incremental implementation for some usage patterns.
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static void Hash(const uint8_t * buffer, const uint64_t length, uint8_t * const hash, const uint64_t seed=0);
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// Does implementation correctly execute test vectors?
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static bool ImplementationVerified();
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// test vectors -- Hash(test_string, seed=0) => test_seed_0
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static const char * test_string;
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static const uint8_t test_seed_0[16];
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static const uint8_t test_seed_1[16];
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private:
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static const uint64_t k0 = 0xC83A91E1;
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static const uint64_t k1 = 0x8648DBDB;
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static const uint64_t k2 = 0x7BDEC03B;
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static const uint64_t k3 = 0x2F5870A5;
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struct { uint64_t v[4]; } state;
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struct { uint8_t b[32]; } input;
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uint64_t bytes;
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};
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// Legacy 128-bit hash functions -- do not use
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void metrohash128_1(const uint8_t * key, uint64_t len, uint32_t seed, uint8_t * out);
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void metrohash128_2(const uint8_t * key, uint64_t len, uint32_t seed, uint8_t * out);
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#endif // #ifndef METROHASH_METROHASH_128_H
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