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/*
* Copyright (C) 2012, 2013 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.
*
*/
#include "config.h"
#include "DocumentSharedObjectPool.h"
#include "Element.h"
#include "ElementData.h"
#include <wtf/UnalignedAccess.h>
namespace WebCore {
// Do comparisons 8 bytes-at-a-time on architectures where it's safe.
#if (CPU(X86_64) || CPU(ARM64)) && !ASAN_ENABLED
ALWAYS_INLINE bool equalAttributes(const uint8_t* a, const uint8_t* b, unsigned bytes)
{
unsigned length = bytes >> 3;
for (unsigned i = 0; i != length; ++i) {
if (WTF::unalignedLoad<uint64_t>(a) != WTF::unalignedLoad<uint64_t>(b))
return false;
a += sizeof(uint64_t);
b += sizeof(uint64_t);
}
ASSERT(!(bytes & 4));
ASSERT(!(bytes & 2));
ASSERT(!(bytes & 1));
return true;
}
#else
ALWAYS_INLINE bool equalAttributes(const uint8_t* a, const uint8_t* b, unsigned bytes)
{
return !memcmp(a, b, bytes);
}
#endif
struct DocumentSharedObjectPool::ShareableElementDataHash {
static unsigned hash(const Ref<ShareableElementData>& data)
{
return computeHash(std::span<const Attribute> { data->m_attributeArray, data->length() });
}
static bool equal(const Ref<ShareableElementData>& a, const Ref<ShareableElementData>& b)
{
if (a->length() != b->length())
return false;
return equalAttributes(reinterpret_cast<const uint8_t*>(a->m_attributeArray), reinterpret_cast<const uint8_t*>(b->m_attributeArray), a->length() * sizeof(Attribute));
}
static constexpr bool safeToCompareToEmptyOrDeleted = false;
};
struct AttributeSpanTranslator {
static unsigned hash(std::span<const Attribute> attributes)
{
return computeHash(attributes);
}
static bool equal(const Ref<ShareableElementData>& a, std::span<const Attribute> b)
{
if (a->length() != b.size())
return false;
return equalAttributes(reinterpret_cast<const uint8_t*>(a->m_attributeArray), reinterpret_cast<const uint8_t*>(b.data()), b.size() * sizeof(Attribute));
}
static void translate(Ref<ShareableElementData>& location, std::span<const Attribute> attributes, unsigned /*hash*/)
{
location = ShareableElementData::createWithAttributes(attributes);
}
};
Ref<ShareableElementData> DocumentSharedObjectPool::cachedShareableElementDataWithAttributes(std::span<const Attribute> attributes)
{
ASSERT(!attributes.empty());
return m_shareableElementDataCache.add<AttributeSpanTranslator>(attributes).iterator->get();
}
} // namespace WebCore
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