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// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_BASE_INTERNAL_HIDE_PTR_H_
#define ABSL_BASE_INTERNAL_HIDE_PTR_H_
#include <cstdint>
namespace absl {
namespace base_internal {
// Arbitrary value with high bits set. Xor'ing with it is unlikely
// to map one valid pointer to another valid pointer.
constexpr uintptr_t HideMask() {
static_assert(sizeof(uintptr_t) == 4 || sizeof(uintptr_t) == 8,
"uintptr_t must be 32 or 64 bits");
return sizeof(uintptr_t) == 8 ? 0xF03A5F7BF03A5F7BULL : 0xF03A5F7BUL;
}
// Hide a pointer from the leak checker. For internal use only.
// Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr
// and all objects reachable from ptr to be ignored by the leak checker.
template <class T>
inline uintptr_t HidePtr(T* ptr) {
return reinterpret_cast<uintptr_t>(ptr) ^ HideMask();
}
// Return a pointer that has been hidden from the leak checker.
// For internal use only.
template <class T>
inline T* UnhidePtr(uintptr_t hidden) {
return reinterpret_cast<T*>(hidden ^ HideMask());
}
} // namespace base_internal
} // namespace absl
#endif // ABSL_BASE_INTERNAL_HIDE_PTR_H_
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