folly/folly/hash/MurmurHash.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */

#pragma once

#include <cstdint>

#include <folly/CPortability.h>
#include <folly/lang/Bits.h>
#include <folly/portability/Constexpr.h>

namespace folly {
namespace hash {

namespace detail {

FOLLY_ALWAYS_INLINE constexpr std::uint64_t shiftMix(std::uint64_t v) { … }

FOLLY_ALWAYS_INLINE constexpr std::uint64_t constexprLoad64(
    const char* s, std::size_t l) { … }

} // namespace detail

/*
 * Implementation of MurmurHash2 hashing algorithm for 64-bit
 * platforms.
 *
 * https://en.wikipedia.org/wiki/MurmurHash
 */
constexpr std::uint64_t murmurHash64(
    const char* key, std::size_t len, std::uint64_t seed) noexcept { … }

} // namespace hash
} // namespace folly