33 lines
935 B
C
33 lines
935 B
C
|
// Copyright 2021 the V8 project authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style license that can be
|
||
|
|
// found in the LICENSE file.
|
||
|
|
|
||
|
|
#ifndef INCLUDE_CPPGC_SENTINEL_POINTER_H_
|
||
|
|
#define INCLUDE_CPPGC_SENTINEL_POINTER_H_
|
||
|
|
|
||
|
|
#include <cstdint>
|
||
|
|
|
||
|
|
namespace cppgc {
|
||
|
|
namespace internal {
|
||
|
|
|
||
|
|
// Special tag type used to denote some sentinel member. The semantics of the
|
||
|
|
// sentinel is defined by the embedder.
|
||
|
|
struct SentinelPointer {
|
||
|
|
static constexpr intptr_t kSentinelValue = 0b10;
|
||
|
|
template <typename T>
|
||
|
|
operator T*() const {
|
||
|
|
return reinterpret_cast<T*>(kSentinelValue);
|
||
|
|
}
|
||
|
|
// Hidden friends.
|
||
|
|
friend bool operator==(SentinelPointer, SentinelPointer) { return true; }
|
||
|
|
friend bool operator!=(SentinelPointer, SentinelPointer) { return false; }
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace internal
|
||
|
|
|
||
|
|
constexpr internal::SentinelPointer kSentinelPointer;
|
||
|
|
|
||
|
|
} // namespace cppgc
|
||
|
|
|
||
|
|
#endif // INCLUDE_CPPGC_SENTINEL_POINTER_H_
|