65 lines
1.8 KiB
C++
65 lines
1.8 KiB
C++
// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef GOOGLE_PROTOBUF_RAW_PTR_H__
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#define GOOGLE_PROTOBUF_RAW_PTR_H__
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#include <algorithm>
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#include "absl/base/optimization.h"
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// Must be included last.
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#include "google/protobuf/port_def.inc"
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namespace google {
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namespace protobuf {
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namespace internal {
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PROTOBUF_EXPORT ABSL_CACHELINE_ALIGNED extern const char
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kZeroBuffer[std::max(ABSL_CACHELINE_SIZE, 64)];
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// This class is trivially copyable/trivially destructible and constexpr
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// constructible. The class allows for storing a raw pointer to a non-trivial
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// object in a constexpr context.
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template <typename T>
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class RawPtr {
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public:
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constexpr RawPtr() : RawPtr(kZeroBuffer) {
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static_assert(sizeof(T) <= sizeof(kZeroBuffer), "");
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static_assert(alignof(T) <= ABSL_CACHELINE_SIZE, "");
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}
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explicit constexpr RawPtr(const void* p) : p_(const_cast<void*>(p)) {}
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bool IsDefault() const { return p_ == kZeroBuffer; }
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void DeleteIfNotDefault() {
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if (!IsDefault()) delete Get();
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}
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void ClearIfNotDefault() {
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if (!IsDefault()) Get()->Clear();
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}
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void Set(const void* p) { p_ = const_cast<void*>(p); }
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T* Get() const { return reinterpret_cast<T*>(p_); }
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T* operator->() const { return Get(); }
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T& operator*() const { return *Get(); }
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private:
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void* p_;
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};
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constexpr void* DefaultRawPtr() {
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return const_cast<void*>(static_cast<const void*>(kZeroBuffer));
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}
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} // namespace internal
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} // namespace protobuf
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} // namespace google
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#include "google/protobuf/port_undef.inc"
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#endif // GOOGLE_PROTOBUF_RAW_PTR_H__
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