| /* |
| * 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 ArrayStorage_h |
| #define ArrayStorage_h |
| |
| #include "ArrayConventions.h" |
| #include "Butterfly.h" |
| #include "IndexingHeader.h" |
| #include "SparseArrayValueMap.h" |
| #include "WriteBarrier.h" |
| #include <wtf/Noncopyable.h> |
| #include <wtf/Platform.h> |
| |
| namespace JSC { |
| |
| // This struct holds the actual data values of an array. A JSArray object points to its contained ArrayStorage |
| // struct by pointing to m_vector. To access the contained ArrayStorage struct, use the getStorage() and |
| // setStorage() methods. It is important to note that there may be space before the ArrayStorage that |
| // is used to quick unshift / shift operation. The actual allocated pointer is available by using: |
| // getStorage() - m_indexBias * sizeof(JSValue) |
| // All slots in ArrayStorage (slots from 0 to vectorLength) are expected to be initialized to a JSValue or, |
| // for hole slots, JSValue(). |
| struct ArrayStorage { |
| WTF_MAKE_NONCOPYABLE(ArrayStorage); |
| private: |
| ArrayStorage() { } // Not directly instantiable. Can only be created as part of a Butterfly. |
| public: |
| |
| static ArrayStorage* from(Butterfly* butterfly) { return reinterpret_cast<ArrayStorage*>(butterfly); } |
| static ArrayStorage* from(IndexingHeader* indexingHeader) { return indexingHeader->arrayStorage(); } |
| |
| Butterfly* butterfly() { return reinterpret_cast<Butterfly*>(this); } |
| IndexingHeader* indexingHeader() { return IndexingHeader::from(this); } |
| |
| // We steal two fields from the indexing header: vectorLength and length. |
| unsigned length() { return indexingHeader()->publicLength(); } |
| void setLength(unsigned length) { indexingHeader()->setPublicLength(length); } |
| unsigned vectorLength() { return indexingHeader()->vectorLength(); } |
| void setVectorLength(unsigned length) { indexingHeader()->setVectorLength(length); } |
| |
| ALWAYS_INLINE void copyHeaderFromDuringGC(const ArrayStorage& other) |
| { |
| m_sparseMap.copyFrom(other.m_sparseMap); |
| m_indexBias = other.m_indexBias; |
| m_numValuesInVector = other.m_numValuesInVector; |
| } |
| |
| bool inSparseMode() |
| { |
| return m_sparseMap && m_sparseMap->sparseMode(); |
| } |
| |
| WriteBarrier<SparseArrayValueMap> m_sparseMap; |
| unsigned m_indexBias; |
| unsigned m_numValuesInVector; |
| #if USE(JSVALUE32_64) |
| uintptr_t m_padding; |
| #endif |
| WriteBarrier<Unknown> m_vector[1]; |
| |
| static ptrdiff_t lengthOffset() { return Butterfly::offsetOfPublicLength(); } |
| static ptrdiff_t vectorLengthOffset() { return Butterfly::offsetOfVectorLength(); } |
| static ptrdiff_t numValuesInVectorOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector); } |
| static ptrdiff_t vectorOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_vector); } |
| static ptrdiff_t indexBiasOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_indexBias); } |
| static ptrdiff_t sparseMapOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_sparseMap); } |
| |
| static size_t sizeFor(unsigned vectorLength) |
| { |
| return ArrayStorage::vectorOffset() + vectorLength * sizeof(WriteBarrier<Unknown>); |
| } |
| }; |
| |
| } // namespace JSC |
| |
| #endif // ArrayStorage_h |
| |