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/*
* Copyright (C) 2012 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef Butterfly_h
#define Butterfly_h
#include "IndexingHeader.h"
#include "PropertyOffset.h"
#include "PropertyStorage.h"
#include <wtf/Noncopyable.h>
#include <wtf/Platform.h>
namespace JSC {
class JSGlobalData;
class SlotVisitor;
struct ArrayStorage;
class Butterfly {
WTF_MAKE_NONCOPYABLE(Butterfly);
private:
Butterfly() { } // Not instantiable.
public:
static size_t totalSize(size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes)
{
ASSERT(indexingPayloadSizeInBytes ? hasIndexingHeader : true);
ASSERT(sizeof(EncodedJSValue) == sizeof(IndexingHeader));
return (preCapacity + propertyCapacity) * sizeof(EncodedJSValue) + (hasIndexingHeader ? sizeof(IndexingHeader) : 0) + indexingPayloadSizeInBytes;
}
static Butterfly* fromBase(void* base, size_t preCapacity, size_t propertyCapacity)
{
return reinterpret_cast<Butterfly*>(static_cast<EncodedJSValue*>(base) + preCapacity + propertyCapacity + 1);
}
static ptrdiff_t offsetOfIndexingHeader() { return IndexingHeader::offsetOfIndexingHeader(); }
static ptrdiff_t offsetOfPublicLength() { return offsetOfIndexingHeader() + IndexingHeader::offsetOfPublicLength(); }
static ptrdiff_t offsetOfVectorLength() { return offsetOfIndexingHeader() + IndexingHeader::offsetOfVectorLength(); }
static Butterfly* createUninitialized(JSGlobalData&, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes);
static Butterfly* create(JSGlobalData&, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, const IndexingHeader&, size_t indexingPayloadSizeInBytes);
static Butterfly* create(JSGlobalData&, Structure*);
static Butterfly* createUninitializedDuringCollection(SlotVisitor&, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes);
IndexingHeader* indexingHeader() { return IndexingHeader::from(this); }
const IndexingHeader* indexingHeader() const { return IndexingHeader::from(this); }
PropertyStorage propertyStorage() { return indexingHeader()->propertyStorage(); }
ConstPropertyStorage propertyStorage() const { return indexingHeader()->propertyStorage(); }
template<typename T>
T* indexingPayload() { return reinterpret_cast<T*>(this); }
ArrayStorage* arrayStorage() { return indexingPayload<ArrayStorage>(); }
static ptrdiff_t offsetOfPropertyStorage() { return -static_cast<ptrdiff_t>(sizeof(IndexingHeader)); }
static int indexOfPropertyStorage()
{
ASSERT(sizeof(IndexingHeader) == sizeof(EncodedJSValue));
return -1;
}
void* base(size_t preCapacity, size_t propertyCapacity) { return propertyStorage() - propertyCapacity - preCapacity; }
void* base(Structure*);
// The butterfly reallocation methods perform the reallocation itself but do not change any
// of the meta-data to reflect that the reallocation occurred. Note that this set of
// methods is not exhaustive and is not intended to encapsulate all possible allocation
// modes of butterflies - there are code paths that allocate butterflies by calling
// directly into Heap::tryAllocateStorage.
Butterfly* growPropertyStorage(JSGlobalData&, size_t preCapacity, size_t oldPropertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes, size_t newPropertyCapacity);
Butterfly* growPropertyStorage(JSGlobalData&, Structure* oldStructure, size_t oldPropertyCapacity, size_t newPropertyCapacity);
Butterfly* growPropertyStorage(JSGlobalData&, Structure* oldStructure, size_t newPropertyCapacity);
Butterfly* growArrayRight(JSGlobalData&, Structure* oldStructure, size_t propertyCapacity, bool hadIndexingHeader, size_t oldIndexingPayloadSizeInBytes, size_t newIndexingPayloadSizeInBytes); // Assumes that preCapacity is zero, and asserts as much.
Butterfly* growArrayRight(JSGlobalData&, Structure*, size_t newIndexingPayloadSizeInBytes);
Butterfly* resizeArray(JSGlobalData&, size_t propertyCapacity, bool oldHasIndexingHeader, size_t oldIndexingPayloadSizeInBytes, size_t newPreCapacity, bool newHasIndexingHeader, size_t newIndexingPayloadSizeInBytes);
Butterfly* resizeArray(JSGlobalData&, Structure*, size_t newPreCapacity, size_t newIndexingPayloadSizeInBytes); // Assumes that you're not changing whether or not the object has an indexing header.
Butterfly* unshift(Structure*, size_t numberOfSlots);
Butterfly* shift(Structure*, size_t numberOfSlots);
};
} // namespace JSC
#endif // Butterfly_h
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