text: /*
   * 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
  