mirror of
https://github.com/darlinghq/darling-WTF.git
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120 lines
4.1 KiB
C++
120 lines
4.1 KiB
C++
/*
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* Copyright (C) 2018-2019 Apple Inc. All rights reserved.
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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
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* are met:
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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* 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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*/
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#pragma once
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#include <wtf/HashTraits.h>
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#include <wtf/PtrTag.h>
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#include <wtf/StdLibExtras.h>
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namespace WTF {
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template<PtrTag tag>
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class MetaAllocatorPtr {
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public:
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MetaAllocatorPtr() = default;
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MetaAllocatorPtr(std::nullptr_t) { }
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explicit MetaAllocatorPtr(void* ptr)
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: m_ptr(tagCodePtr<tag>(ptr))
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{
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assertIsNotTagged(ptr);
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}
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explicit MetaAllocatorPtr(uintptr_t ptrAsInt)
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: MetaAllocatorPtr(reinterpret_cast<void*>(ptrAsInt))
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{ }
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template<typename T = void*>
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T untaggedPtr() const { return bitwise_cast<T>(untagCodePtr<tag>(m_ptr)); }
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template<PtrTag newTag, typename T = void*>
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T retaggedPtr() const { return bitwise_cast<T>(retagCodePtr<tag, newTag>(m_ptr)); }
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// Disallow any casting operations (except for booleans).
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template<typename T, typename = std::enable_if_t<!std::is_same<T, bool>::value>>
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operator T() = delete;
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explicit operator bool() const { return !!m_ptr; }
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bool operator!() const { return !m_ptr; }
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bool operator==(MetaAllocatorPtr other) const { return m_ptr == other.m_ptr; }
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bool operator!=(MetaAllocatorPtr other) const { return m_ptr != other.m_ptr; }
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MetaAllocatorPtr operator+(size_t sizeInBytes) const { return MetaAllocatorPtr(untaggedPtr<uint8_t*>() + sizeInBytes); }
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MetaAllocatorPtr operator-(size_t sizeInBytes) const { return MetaAllocatorPtr(untaggedPtr<uint8_t*>() - sizeInBytes); }
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MetaAllocatorPtr& operator+=(size_t sizeInBytes)
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{
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return *this = *this + sizeInBytes;
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}
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MetaAllocatorPtr& operator-=(size_t sizeInBytes)
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{
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return *this = *this - sizeInBytes;
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}
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enum EmptyValueTag { EmptyValue };
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enum DeletedValueTag { DeletedValue };
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MetaAllocatorPtr(EmptyValueTag)
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: m_ptr(emptyValue())
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{ }
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MetaAllocatorPtr(DeletedValueTag)
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: m_ptr(deletedValue())
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{ }
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bool isEmptyValue() const { return m_ptr == emptyValue(); }
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bool isDeletedValue() const { return m_ptr == deletedValue(); }
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unsigned hash() const { return PtrHash<void*>::hash(m_ptr); }
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private:
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static void* emptyValue() { return reinterpret_cast<void*>(1); }
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static void* deletedValue() { return reinterpret_cast<void*>(2); }
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void* m_ptr { nullptr };
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};
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template<PtrTag tag>
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struct MetaAllocatorPtrHash {
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static unsigned hash(const MetaAllocatorPtr<tag>& ptr) { return ptr.hash(); }
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static bool equal(const MetaAllocatorPtr<tag>& a, const MetaAllocatorPtr<tag>& b)
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{
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return a == b;
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}
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static constexpr bool safeToCompareToEmptyOrDeleted = true;
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};
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template<typename> struct DefaultHash;
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template<PtrTag tag> struct DefaultHash<MetaAllocatorPtr<tag>> : MetaAllocatorPtrHash<tag> { };
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template<PtrTag tag> struct HashTraits<MetaAllocatorPtr<tag>> : public CustomHashTraits<MetaAllocatorPtr<tag>> { };
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} // namespace WTF
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using WTF::MetaAllocatorPtr;
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