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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
#include "util/random.h"
#include <stdint.h>
#include <string.h>
#include <thread>
#include <utility>
#include "port/likely.h"
#include "util/thread_local.h"
#ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
#define STORAGE_DECL static __thread
#else
#define STORAGE_DECL static
#endif
namespace ROCKSDB_NAMESPACE {
Random* Random::GetTLSInstance() {
STORAGE_DECL Random* tls_instance;
STORAGE_DECL std::aligned_storage<sizeof(Random)>::type tls_instance_bytes;
auto rv = tls_instance;
if (UNLIKELY(rv == nullptr)) {
size_t seed = std::hash<std::thread::id>()(std::this_thread::get_id());
rv = new (&tls_instance_bytes) Random((uint32_t)seed);
tls_instance = rv;
}
return rv;
}
} // namespace ROCKSDB_NAMESPACE
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