225 lines
7.5 KiB
C++
225 lines
7.5 KiB
C++
// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// A common header that is included across all protobuf headers. We do our best
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// to avoid #defining any macros here; instead we generally put macros in
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// port_def.inc and port_undef.inc so they are not visible from outside of
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// protobuf.
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#ifndef GOOGLE_PROTOBUF_PORT_H__
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#define GOOGLE_PROTOBUF_PORT_H__
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#include <cassert>
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#include <cstddef>
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#include <cstdint>
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#include <new>
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#include <string>
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#include <type_traits>
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#include <typeinfo>
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#include "absl/meta/type_traits.h"
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#include "absl/strings/string_view.h"
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#include "absl/types/optional.h"
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// must be 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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class MessageLite;
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namespace internal {
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// See comments on `AllocateAtLeast` for information on size returning new.
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struct SizedPtr {
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void* p;
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size_t n;
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};
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// Debug hook allowing setting up test scenarios for AllocateAtLeast usage.
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using AllocateAtLeastHookFn = SizedPtr (*)(size_t, void*);
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// `AllocAtLeastHook` API
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constexpr bool HaveAllocateAtLeastHook();
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void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context = nullptr);
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#if !defined(NDEBUG) && defined(ABSL_HAVE_THREAD_LOCAL) && \
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defined(__cpp_inline_variables)
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// Hook data for current thread. These vars must not be accessed directly, use
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// the 'HaveAllocateAtLeastHook()` and `SetAllocateAtLeastHook()` API instead.
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inline thread_local AllocateAtLeastHookFn allocate_at_least_hook = nullptr;
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inline thread_local void* allocate_at_least_hook_context = nullptr;
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constexpr bool HaveAllocateAtLeastHook() { return true; }
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inline void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context) {
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allocate_at_least_hook = fn;
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allocate_at_least_hook_context = context;
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}
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#else // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables
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constexpr bool HaveAllocateAtLeastHook() { return false; }
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inline void SetAllocateAtLeastHook(AllocateAtLeastHookFn fn, void* context) {}
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#endif // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables
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// Allocates at least `size` bytes. This function follows the c++ language
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// proposal from D0901R10 (http://wg21.link/D0901R10) and will be implemented
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// in terms of the new operator new semantics when available. The allocated
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// memory should be released by a call to `SizedDelete` or `::operator delete`.
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inline SizedPtr AllocateAtLeast(size_t size) {
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#if !defined(NDEBUG) && defined(ABSL_HAVE_THREAD_LOCAL) && \
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defined(__cpp_inline_variables)
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if (allocate_at_least_hook != nullptr) {
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return allocate_at_least_hook(size, allocate_at_least_hook_context);
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}
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#endif // !NDEBUG && ABSL_HAVE_THREAD_LOCAL && __cpp_inline_variables
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return {::operator new(size), size};
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}
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inline void SizedDelete(void* p, size_t size) {
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#if defined(__cpp_sized_deallocation)
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::operator delete(p, size);
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#else
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// Avoid -Wunused-parameter
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(void)size;
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::operator delete(p);
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#endif
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}
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inline void SizedArrayDelete(void* p, size_t size) {
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#if defined(__cpp_sized_deallocation)
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::operator delete[](p, size);
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#else
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// Avoid -Wunused-parameter
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(void)size;
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::operator delete[](p);
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#endif
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}
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// Tag type used to invoke the constinit constructor overload of classes
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// such as ArenaStringPtr and MapFieldBase. Such constructors are internal
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// implementation details of the library.
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struct ConstantInitialized {
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explicit ConstantInitialized() = default;
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};
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// Tag type used to invoke the arena constructor overload of classes such
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// as ExtensionSet and MapFieldLite in aggregate initialization. These
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// classes typically don't have move/copy constructors, which rules out
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// explicit initialization in pre-C++17.
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struct ArenaInitialized {
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explicit ArenaInitialized() = default;
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};
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template <typename To, typename From>
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inline To DownCast(From* f) {
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static_assert(
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std::is_base_of<From, typename std::remove_pointer<To>::type>::value,
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"illegal DownCast");
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#if PROTOBUF_RTTI
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// RTTI: debug mode only!
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assert(f == nullptr || dynamic_cast<To>(f) != nullptr);
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#endif
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return static_cast<To>(f);
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}
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template <typename ToRef, typename From>
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inline ToRef DownCast(From& f) {
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using To = typename std::remove_reference<ToRef>::type;
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static_assert(std::is_base_of<From, To>::value, "illegal DownCast");
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#if PROTOBUF_RTTI
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// RTTI: debug mode only!
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assert(dynamic_cast<To*>(&f) != nullptr);
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#endif
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return *static_cast<To*>(&f);
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}
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// Looks up the name of `T` via RTTI, if RTTI is available.
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template <typename T>
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inline absl::optional<absl::string_view> RttiTypeName() {
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#if PROTOBUF_RTTI
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return typeid(T).name();
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#else
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return absl::nullopt;
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#endif
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}
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// Helpers for identifying our supported types.
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template <typename T>
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struct is_supported_integral_type
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: absl::disjunction<std::is_same<T, int32_t>, std::is_same<T, uint32_t>,
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std::is_same<T, int64_t>, std::is_same<T, uint64_t>,
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std::is_same<T, bool>> {};
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template <typename T>
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struct is_supported_floating_point_type
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: absl::disjunction<std::is_same<T, float>, std::is_same<T, double>> {};
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template <typename T>
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struct is_supported_string_type
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: absl::disjunction<std::is_same<T, std::string>> {};
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template <typename T>
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struct is_supported_scalar_type
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: absl::disjunction<is_supported_integral_type<T>,
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is_supported_floating_point_type<T>,
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is_supported_string_type<T>> {};
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template <typename T>
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struct is_supported_message_type
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: absl::disjunction<std::is_base_of<MessageLite, T>> {
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static constexpr auto force_complete_type = sizeof(T);
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};
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// To prevent sharing cache lines between threads
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#ifdef __cpp_aligned_new
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enum { kCacheAlignment = 64 };
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#else
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enum { kCacheAlignment = alignof(max_align_t) }; // do the best we can
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#endif
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// The maximum byte alignment we support.
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enum { kMaxMessageAlignment = 8 };
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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_PORT_H__
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