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// Copyright 2018 The Abseil Authors.
//
// 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
//
//
// 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.
#include "absl/hash/internal/hash.h"
#include <cstddef>
#include <cstdint>
#include <type_traits>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/hash/internal/low_level_hash.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace hash_internal {
uint64_t MixingHashState::CombineLargeContiguousImpl32(
uint64_t state, const unsigned char* first, size_t len) {
while (len >= PiecewiseChunkSize()) {
state = Mix(
state ^ hash_internal::CityHash32(reinterpret_cast<const char*>(first),
PiecewiseChunkSize()),
kMul);
len -= PiecewiseChunkSize();
first += PiecewiseChunkSize();
}
// Handle the remainder.
return CombineContiguousImpl(state, first, len,
std::integral_constant<int, 4>{});
}
uint64_t MixingHashState::CombineLargeContiguousImpl64(
uint64_t state, const unsigned char* first, size_t len) {
while (len >= PiecewiseChunkSize()) {
state = Mix(state ^ Hash64(first, PiecewiseChunkSize()), kMul);
len -= PiecewiseChunkSize();
first += PiecewiseChunkSize();
}
// Handle the remainder.
return CombineContiguousImpl(state, first, len,
std::integral_constant<int, 8>{});
}
ABSL_CONST_INIT const void* const MixingHashState::kSeed = &kSeed;
uint64_t MixingHashState::LowLevelHashImpl(const unsigned char* data,
size_t len) {
return LowLevelHashLenGt32(data, len, Seed(), &kStaticRandomData[0]);
}
} // namespace hash_internal
ABSL_NAMESPACE_END
} // namespace absl