c34026b101
note: done using ```sh git grep -l "2010-2024 Google" | xargs sed -i 's/2010-2024 Google/2010-2025 Google/' ```
76 lines
2.0 KiB
C++
76 lines
2.0 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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#include "ortools/base/hash.h"
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namespace operations_research {
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// This is a copy of the code from https://github.com/ztanml/fast-hash
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// We include it here for build simplicity.
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//
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// We have made 2 modification:
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// - replace the #define with an inline method to fix compilation on windows.
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// - rename mix into mix_internal and hide inside a unnamed namespace.
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namespace {
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// Compression function for Merkle-Damgard construction.
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// This function is generated using the framework provided.
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inline uint64_t mix_internal(uint64_t h) {
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h ^= h >> 23;
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h *= 0x2127599bf4325c37ULL;
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h ^= h >> 47;
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return h;
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}
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} // namespace
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uint64_t fasthash64(const void* buf, size_t len, uint64_t seed) {
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const uint64_t m = 0x880355f21e6d1965ULL;
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const uint64_t* pos = (const uint64_t*)buf;
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const uint64_t* end = pos + (len / 8);
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const unsigned char* pos2;
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uint64_t h = seed ^ (len * m);
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uint64_t v;
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while (pos != end) {
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v = *pos++;
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h ^= mix_internal(v);
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h *= m;
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}
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pos2 = (const unsigned char*)pos;
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v = 0;
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switch (len & 7) {
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case 7:
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v ^= (uint64_t)pos2[6] << 48;
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case 6:
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v ^= (uint64_t)pos2[5] << 40;
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case 5:
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v ^= (uint64_t)pos2[4] << 32;
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case 4:
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v ^= (uint64_t)pos2[3] << 24;
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case 3:
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v ^= (uint64_t)pos2[2] << 16;
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case 2:
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v ^= (uint64_t)pos2[1] << 8;
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case 1:
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v ^= (uint64_t)pos2[0];
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h ^= mix_internal(v);
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h *= m;
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}
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return mix_internal(h);
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}
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} // namespace operations_research
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