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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).
#pragma once
#include <type_traits>
#include "rocksdb/rocksdb_namespace.h"
namespace ROCKSDB_NAMESPACE {
// The helper function to assert the move from dynamic_cast<> to
// static_cast<> is correct. This function is to deal with legacy code.
// It is not recommended to add new code to issue class casting. The preferred
// solution is to implement the functionality without a need of casting.
template <class DestClass, class SrcClass>
inline DestClass* static_cast_with_check(SrcClass* x) {
DestClass* ret = static_cast<DestClass*>(x);
#ifdef ROCKSDB_USE_RTTI
assert(ret == dynamic_cast<DestClass*>(x));
#endif
return ret;
}
// A wrapper around static_cast for lossless conversion between integral
// types, including enum types. For example, this can be used for converting
// between signed/unsigned or enum type and underlying type without fear of
// stripping away data, now or in the future.
template <typename To, typename From>
inline To lossless_cast(From x) {
using FromValue = typename std::remove_reference<From>::type;
static_assert(
std::is_integral<FromValue>::value || std::is_enum<FromValue>::value,
"Only works on integral types");
static_assert(std::is_integral<To>::value || std::is_enum<To>::value,
"Only works on integral types");
static_assert(sizeof(To) >= sizeof(FromValue), "Must be lossless");
return static_cast<To>(x);
}
} // namespace ROCKSDB_NAMESPACE
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