87 lines
1.8 KiB
C++
87 lines
1.8 KiB
C++
// Copyright 2010-2025 Google LLC
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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 OR_TOOLS_BASE_HASH_H_
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#define OR_TOOLS_BASE_HASH_H_
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#include <array>
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#include <cstdint>
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#include <string>
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#include <utility>
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// In SWIG mode, we don't want anything besides these top-level includes.
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#if !defined(SWIG)
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namespace operations_research {
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uint64_t fasthash64(const void* buf, size_t len, uint64_t seed);
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// 64 bit version.
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static inline void mix(uint64_t& a, uint64_t& b, uint64_t& c) { // NOLINT
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a -= b;
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a -= c;
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a ^= (c >> 43);
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b -= c;
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b -= a;
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b ^= (a << 9);
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c -= a;
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c -= b;
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c ^= (b >> 8);
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a -= b;
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a -= c;
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a ^= (c >> 38);
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b -= c;
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b -= a;
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b ^= (a << 23);
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c -= a;
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c -= b;
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c ^= (b >> 5);
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a -= b;
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a -= c;
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a ^= (c >> 35);
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b -= c;
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b -= a;
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b ^= (a << 49);
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c -= a;
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c -= b;
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c ^= (b >> 11);
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a -= b;
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a -= c;
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a ^= (c >> 12);
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b -= c;
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b -= a;
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b ^= (a << 18);
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c -= a;
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c -= b;
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c ^= (b >> 22);
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}
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} // namespace operations_research
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#endif // SWIG
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namespace util_hash {
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inline uint64_t Hash(uint64_t num, uint64_t c) {
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uint64_t b = uint64_t{0xe08c1d668b756f82}; // More of the golden ratio.
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operations_research::mix(num, b, c);
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return c;
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}
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inline uint64_t Hash(uint64_t a, uint64_t b, uint64_t c) {
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operations_research::mix(a, b, c);
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return c;
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}
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} // namespace util_hash
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#endif // OR_TOOLS_BASE_HASH_H_
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