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/*
* Copyright (C) 2010 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. AND ITS CONTRIBUTORS ``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 ITS 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 AtomicStringKeyedMRUCache_h
#define AtomicStringKeyedMRUCache_h
#include <wtf/text/AtomicString.h>
namespace WebCore {
template<typename T, size_t capacity = 4>
class AtomicStringKeyedMRUCache {
public:
T get(const AtomicString& key)
{
if (key.isNull()) {
DEFINE_STATIC_LOCAL(T, valueForNull, (createValueForNullKey()));
return valueForNull;
}
for (size_t i = 0; i < m_cache.size(); ++i) {
if (m_cache[i].first == key) {
size_t foundIndex = i;
if (foundIndex + 1 < m_cache.size()) {
Entry entry = m_cache[foundIndex];
m_cache.remove(foundIndex);
foundIndex = m_cache.size();
m_cache.append(entry);
}
return m_cache[foundIndex].second;
}
}
if (m_cache.size() == capacity)
m_cache.remove(0);
m_cache.append(std::make_pair(key, createValueForKey(key)));
return m_cache.last().second;
}
private:
T createValueForNullKey();
T createValueForKey(const AtomicString&);
typedef pair<AtomicString, T> Entry;
typedef Vector<Entry, capacity> Cache;
Cache m_cache;
};
}
#endif // AtomicStringKeyedMRUCache_h
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